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HomeMy WebLinkAbout52 Development Permit 284 Summit Four PlexesDEVELOPMENT PERMIT PERMIT NO. #284 FOR AREAS OUTSIDE THE SPECIAL FLOOD HAZARD AREA RE: CHAPTER 13 OF THE COLLEGE STATION CITY CODE SITE LEGAL DESCRIPTION: SITE ADDRESS: 1401 -1407 Summit Street OWNER: Tony Jones DRAINAGE BASIN: Bee Creek Tributary ''B" TYPE OF DEVELOPMENT: This permit is valid for clearing, grading, and all site work, extension of existing water line and sewer line, and construction of all buildings and drainage structures on site as per the submitted plans for Summit Fourplexes. The Contractor shall take all necessary precautions to prevent silt and debris from leaving the immediate construction site in accordance with the approved erosion control plan as well as the City of College Station Drainage Policy and Design Criteria. Contractor shall assure that all disturbed areas are sodden and establishment of vegetation occurs prior to removal of any silt fencing of hay bales used for temporary erosion control. Contractor shall also insure that any disturbed vegetation be returned to its original condition, placement and state. Contractor shall be responsible for any damage to adjacent properties, city streets or infrastructure due to heavy machinery and/or equipment as well as erosion, siltation or sedimentation resulting from the permitted work. This permit expires six months from the date of issuance. In accordance with Chapter 13 of the Code of Ordinances of the City of College Station, measures shall be taken to insure that debris from construction, erosion, and sedimentation shall not be deposited in city streets, or existing drainage facilities. I hereby grant this permit for development of an area outside the special flood hazard area. All development shall be in accordance with the plans and specifications submitted to and approved by the City Engineer in the development permit application for the above named project and all of the codes and ordinances of the City of College Station that apply . Date ~k Date Owner/ Agent Date I I I I ' I I I I I I I ' ENGINEERING REPORT to accompany the repl a t of Block 14A, Southwood Valley -Section 19 College Station, BRAZOS COUNTY, TEXAS Block 14A of Southwood Valley -Section 19 is situated adjacent to Summit Street, between Southwood Drive and Hilltop Drive in Southwood Valley, College Station, Brazos County, Texas. Block 14A consists of 4 lots, established within the bounds of a 1.64 acre tract. Additionally, the project is partially surrounded by developed property. but future expansion of the proposed facilities will likely not be necessary. Soils within the area have shown historically to be quite stable. No faults exist within the project area, and no stability problems are foreseen, other than those caused by the expansive clays typical of Brazos County. Sanitary sewer needs are met by two separate 6" diameter P.V.C. SDR. 26-3034 sanitary sewer lines that run parallel to Summit Street, 8 feet off of the back of curb. Sanitary sewer line "A" (on sheet S 1). begins at the existing manhole (near the lot line between Lots 2R and 3R) and runs southwest from station 0+00 to station 1+25.73, at a grade of 0.60%. Sanitary sewer line "B" (on sheet Sl) begins at the existing manhole and runs northeast from station O+OO to station 1+50.73, at a grade of 0.60%. The pipe loading was calculated to be 0 .023 cubic feet per second (cfs). This loading is calculated by considering a 4-plex on each lot, with each single unit having 3 bedrooms. One resident was a ssumed for each bedroom, totaling 12 residents per lot. A loading of 100 gallons per day (gpd) was assum~d for each resident to get the daily loading factor. The daily loading is multiplied by 3 to get the peak loading and 10% of the daily loading accounts for infiltration. The infiltration is added to the peak loading to calculate the total loading. These calculations are shown below: Daily loading = 4 lots * 12 residents per lot * 100 gpd per resident = 4800 gpd L Oc;7 l 1-1 :~f' EX;~,(,"/ l5 F /; vtf!_ Peak loading= Daily loading* 3 = 4800 gpd * 3 = 14400 gpd Infiltration = Daily loading * 0. 10 = 4800 gpd * 0 .10 = 480 gpd Total loading= Peak loading+ Infiltration = 14400 gpd + 480 gpd = 14880 gpd ~:/"=ZIJ' 1 I ' / '? c:;VYYI yn (/-)hu/:- Engineer's Estimate For Sidewalk, Water, & Sanitary Sewer Improvements To Block 14A Southwood Valley -Section 19 College Station, Brazos County, Texas May, 1995 w ater mprovements: Item .:-'-•t~--·« -· .!, Estimated Unit I Q•{~c Unit .<·~··, ¥:·~: -No. "-·" _ _,.!.,, •• ,..;:.~~ .... .... ,_, -·' Quantity Price 1. 2" Diameter Type "K" Copper Service 45 L.F . $14 .00 Line (0-5 feet) 2. 2" Diameter Type "K" Copper Service 5 L.F. $15 .00 Line (5-7 feet) 3. 1 1/2" Diameter Type "K" Copper 60 L.F . $14 .00 Service Line (0-5 feet) 4 . 6"X2" Bronze Service Saddle w/2" 3 Ea. $250.00 Corp . Stop @ End 5. 4" Diameter Machine Boring w/4" 90 L.F . $10.00 Diameter Steel Casing (3/8 " Min. Wall Thickness) 6. Removal of Existing Sidewalk 32 S.F. $3.50 7. Reinforced Concrete Sidewalk 32 S.F . $2.50 8. Trench Safety 1 L.S. $5.00 Total Amount of Cost For Water Improvements: : 4 -f {c'!C~ Amount ;,i~J,-":-;:-, '"''' .•• ,.,,::'.;i't' ··; $630 .00 $75.00 $840 .00 $750.00 ' $900.00 $112 .00 $80 .00 $5.00 $3,392.00 I J j v 1. 2 . 3 . 4 . Engineer's Estimate For Sidewalk, Water, & Sanitary Sewer Improvements To Block 14A Southwood Valley -Section 19 College Station , Brazos County, Texas May, 1995 (Continued) Estimated Quant it Unit Price 6" Diameter SOR. 26-3034 P.V.C . 159 L.F . $15 .00 San . Swr. Line 0-5 feet 6" Diameter SOR. 26-3034 P.V.C . 118 L.F . $16.00 San . Swr. Line 5-7 feet Standard Manhole 0 - 8 feet 2 Ea . $1 ,000.00 Trench Safet L.S . $118.00 Total Amount Of Cost For Sanitary Sewer Improvements: 1 ewa lk I t mprovemen s: Item Description Estimated Unit Unit No. -. ~ Quantity Price 1. 4" Reinforced Concrete Sidewalk w/#6 2392 S.F. $2 .50 -6"X6" Welded Wire Mesh (3000 p .s .i., 28-day strength concrete), Provide 2" Thick Sand Leveling Cushion Total Amount Of Cost For Sidewalk Improvements: $2 ,385.00 $1 ,888 .00 $2 ,000.00 $118 .00 $6,391 .00 Amount $5,980.00 $5,980 .00 Engineer's Estimate For Sidewalk, Water, & Sanitary Sewer Improvements To Block 14A Southwood Valley -Section 19 College Station, Brazos County, Texas May, 1995 (Continued) Summary Water Improvements : Sanitary S ewer Improvements: Sidewalk Improvem ent s: Total Estimated Cost: $3 ,392.00 $6 ,391 .00 $5 ,980 .00 $15,763.00 • U@{f: '-" /f!it/~~~/ V1 ~;~} ~I ~.&J--~. STAFFPRCREPORT ~o-;f ~ IO~ Summit Fourplexes { ~ ,e; J '11 ,..,....,...,. I Case #95-500 iscretionaiy Items: o/ ~ X If the site plan is approved , it is with the assumption that the proposed drainage plan is · I correct. If there is a substantial change to the site plan due to changes in the drainage of the site , staff has the discretion to require the revised site plan to be r 7Yiewed bJ. !he /J Project Review Committee . ~tfCJ--~ ~~ ~ . ~ Sidewalks are required on all four treets boundin ~ the property except for Summit Street that has an existing sidewalk. VJ~ a..k'e-r-o-.;),</, 11 1 ?(~flt . Ordinance Requirements : ~ ~ I 7 I Tabulate the total density of the project and p the number of dwelling units per acre . Tabulate the gross square footage of the proposed buildings. Show the minimum , maximum and average water, sewer and irrigation demands for the proposed development so that the meter sizes can be established . Note that there is no floodplain on the subject property . Show the ~th driveways along Summit Street where the driveway meets the first parking space. Provide curbing around the entire perimeter of the parking lot including at the ends of the parking stalls . Comments/Concerns : If the Summit Street right-of-way is abandoned , fire lanes will be required for the proposed fourplexes to provide adequate coverage to the site . Cno d. 06--F~ . The landscape plan exceeds the minimum point requirements by 170 points per lot. In detail #3 on the site plan, do not allow the apron at the street to toe under. ~.9--'ij't1•~~ • Extensive off site conduit will need to be installed along tttllwood Drive from a power ~/ pole to the sou o roperty and to a comer o mmit and Southwood . Southwood will need to be bored and con · ded al the south property line to an appropriate pad location. From the pad location, co 'llneedJQ be installed to each of the buildings . The developer is ~e.sp~· e for approximatefY2U3ofthe total cost of service . Coordinate details with Ele~1 Line Designer Don Lusk at (409) 764-3660 . Conduit is required from the proposed buildings to the existing telephone cable along F .M . 2818 . Coordinate details with G.T .E . Representative Laverne Akin at (409) 821-4723 . ( ' . : . • I I I I I I I I I I 1 DRAINAGE COMPUTATIONS for Summit Four-Plexes being LOTS 1R-4R of a REPLAT of BLOCK 14A Southwood Valley -Section 19 College Station, Brazos County, Texas Prepared for Tony Jones 4475 Hicks Lane College Station, Texas 77845 Prepared by.· ........ Garrett Engineering I 4444 Carter Creek Parkway -Suite 108 ... , ...... "~' Bryan, Texas 77802 ---~~.~-~. /1 ~' 1 Telephone: (409) 846-2688 /1-..~---~M ·:. :}~1l ~ ~.:" ~ . x_\\_~~ * March, 1995 * ' ' I ........ -/ clj /z; _1 l l l I f 1.,'t l /-- , ' ")/ 'I l 1,1<: L1c,l /._1t. (l l~-/~('J / 5 ,;;; )J Jpc a t 0&L /f /c?t-J. I DRAINAGE COMPUTATIONS for A Re plat of Block 14A Southwood Valley -Section 19 ·college Station, Brazos County, Texas *April, 1995 * SUMMARY The project is situated off F.M . 2818 between Southwood and Hilltop drives in the Southwood Valley Subdivision, College Station, Brazos County, Texas. Block 14A of Southwood Valley -Section 19 consists of 4 lots being established within the bounds of the 1.94 acre tract The total drainage area tributary to the project is 1.94 acres. The pre-development run-off coefficient was estimated to be 0.40, while taking into account typical residential site improvements would result in a post-d eve lopment run-off coefficient of 0.63. Detention facilities will be constructed at various locations of the property to ensure the collection of necessary runoff volumes and make use of practical drainage patterns. Three detention ponds are des igned with capacity to facilitate up to and including the 100-year storm event, and discharge at a rate less than the current pre-development peak discharge rate. The detention ponds will intercept, store and meter run-off from 1.20 acres of the project. The run-off generated on U1e remaining 0.74 acres will "free- flow " across the project site umnetered off the property. These report calculations are summarized according to the following methodology . (The report is divided into 3 secti ons corres ponding to Ponds A through C .) Beginning on page 1 of each section, based on the total tributary drainage area of the project (being 1.94 acres for the whole tract, but reflecting the specific drain age area for the corresponding pond in that section), the pre-development run-off coefficient (being assumed at 0.40), and a minimum time of concentration of 10 minutes, the relative pre-development peak di scharge rate ("Q") was determined. The Rational Method was utilized to compute the estimated peak pre-develo pment discharge rates. The equation that represents the Rational Method is as follows: Q = CIA. "Q" is the peak discharge rate in cubic feet per second, "C" is the run-off coefficient, assumed to be 0.40 in U1e pre-development condition, "I" is the storm intensity in inches per hour, and "A" is the area of the drain age basin in acres. Computations on page 2 are based on the relative tributary area, the post-development run-off coefficient of 0 .63 (being weighted according to the relative amounts of pervio us and impe rvious surface area), a minimum time of concentration of 10 minutes, to yield the relative pre-development peak discharge rate ("Q") (assuming the same minimum time of concentration of 10 minutes). The Rational Method was again utilized to compute the estimated peak post-development discharge rates. The equation that represents the Rational Method is as follows: Q = CIA, where; "Q" is the peak discharge rate in cubic feet per second. The "C" variable is the run-off coefficient (In the pos t-development condition "C" is assumed to be 0.63 .) "I" represents the rainfall intensity in inches pe r hour, and similarly "A" is the area of t11 e bas in in acres . Comparison of the peak pre-development discharge rate to the post-development discharge rate is included in the report to aid the designer in establishing a preliminary "target" of detention volume requ ired . This preliminary estimate is determined as th e volwne difference generated between the pre- development and pos t-development hydrographs. (See pages 9-11 for pre-d evelopment and post- dcvelopment bydrographs.) Please note that the po s t-development hydrograph shown on these same graphs ass umes no detention and refl ects the "worst-case" scenario that all run-off is allowed to free-flow. I I I I I I ' ENGINEERING REPORT for water improvements to Block 14A, Southwood Valley -Section 19 College Station, BRAZOS COUNTY, TEXAS Biock 14A of Southwood Valley -s ·ection 19 is situated adjacent to Summit Street. between Southwood Drive and Hilltop Drive in Southwood Valley, College Station, Brazos County, Texas. Block 14A consists of 4 lots, established within the bounds of a 1.64 acre tract. Additionally, the project is partially surrounded by developed property, but future expansion of the proposed facilities will likely not be necessary. Soils within the area have shown historically to be quite stable. No faults exist within the project area, and no stability problems are foreseen, other than those caused by the expansive clays typical of Brazos County. Water needs are met with a combination of 2" diameter and 1 1 /2'~ diameter Type "K" copper service line. Water line "A" is a 2" diameter line that ties into the 6" diameter line that runs parallel to Summit Street, and crossed under Summit Street (55.0 ft.) to the lot line between Lot 2R and Lot 3R (sheet W-1). Water line "B" is a 1 1 /2" diameter line that ties into the 6" diameter water line and crosses (55.0 ft.) under Summit Street to Lot 4R (sheet W-1). Water service to Lot 1 R comes from a 5 ft. long, 1 1 /2" diameter Type "K" copper service line that ties into the existing 8" water line that runs parallel to Southwood Drive. The meter loading was calculated to be 0.625 gallons per minute (gpm). This loading is calculated by considering a 4-plex on each lot, with each single unit having 3 bedrooms. One resident is assumed for each bedroom, with 100 gallons per day (gpd) assumed for each resident to get the daily loading factor. The daily loading is multiplied by 3 to the maximum loading per meter. These calculations are shown below: Total loading = Peak loading = 0.625 gpm fiv er 1-'lMl 1/1 . e.; /Q 'b < JJ:d>:Yf/p-JJ o/ fa-C' ·z-. ~:)J)J ·' lf £{fr r:J ft2 ·z z.~ J7):>n F_J CJ 4wc__ 4 ,, ?;, p oQfV ~ f2{ --1c(1V17 }!_) UO ~UD :1 4f . - 1L 9,9 ~ )wYJkf fZDJjffl{J !flJ J)l/lJMjZJ • I : ~ Q ! 9Jm 9 Jfl ~'dci.o/r:i ;; p1 g , fl<(f 1 'jJJJ 'P J-9/ld U :pv~ U.! Lfi~ · CjO/ ~J?<{ UJ wp ucx:L oN · c y-'7 /°! j°7fl'~ /VIN l/uy.1X 7 ,, \W/d 7J~. '"/ • {)('l.or;0 :t1'{f ;x/_PfJ ft! .:PJ9 ;()v -de nrv · ·~121&"5 llJ/VJ(} g Engineering Report For Sanitary Sewer Improvements To Block 14A, Southwood Valley -Section 19 College Station, Brazos County, Texas Prepared For: Tony Jones 4475 Hicks Lane College Station, Texas 77845 Prepared By: GARRETT· ENGINEERING . *May, 1995 * Engineering Report For Sanitary Sewer Improvements To Block 14A, Southwood Valley -Section 19 College Station, Brazos County, Texas Prepared For: Tony Jones 4475 Hicks Lane College Station, Texas 77845 Prepared By: GARRETT ENGINEERING . CONSUL TING BIGI MilG & LAND SURV!\'lllG ...... CAR1Dl Cll!Bt PAllllCWAY, SUITE 1a • mlYAll, 1!XAS 17112 • (.., ~ • (_, l•~DM *May, 1995 * ENGINEERING REPORT to accompany the replat of Block 14A, Southwood Valley -Section 19 College Station, BRAZOS COUNTY, TEXAS Block I 4A of Southwood Valley -Section I 9 is situated adjacent to Summit Street, between Southwood Drive and Hilltop Drive in Southwood Valley, College Station, Brazos County, Texas. Block I4A consists of 4 lots, established within the bounds of a I .64 acre tract. Additionally, the project is partially surrounded by developed property, but future expansion of the proposed facilities will likely not be necessary. Soils within the area have shown historically to be quite stable. No faults exist within the project area, and no stability problems are foreseen, other than those caused by the expansive clays typical of Brazos County. Sanitary sewer needs are met by two separate 6" diameter P.V.C. SDR. 26-3034 sanitary sewer lines that run parallel to Summit Street, 8 feet off of the back of curb. Sanitary sewer line "A" (on sheet SI), begins at the existing manhole (near the lot line between Lots 2R and 3R) and runs southwest from station 0+00 to station I +25. 73, at a grade of 0.60%. Sanitary sewer line "B" (on sheet SI) begins at the existing manhole and runs northeast from station O+OO to station I+50.73, at a grade of 0.60%. The pipe loading was calculated to be 0.023 cubic feet per second (cfs). This loading is calculated by considering a 4-plex on each lot, with each single unit having 3 bedrooms. One resident was assumed for each bedroom, totaling I2 residents per lot. A loading of I 00 gallons per day (gpd) was assumed for each resident to get the daily loading factor. The daily loading is multiplied by 3 to get the peak loading and I 0% of the daily loading accounts for infiltration. The infiltration is added to the peak lo ading to calculate the total loading. These calculations are shown below: Daily loading= 4 lots * I2 residents per lot* IOO gpd per resident = 4800 gpd Peak loading = Daily loading * 3 = 4800 gpd * 3 = I4400 gpd Infiltration = Daily lo ading * O. I 0 = 4800 gpd * 0.10 = 480 gpd Total loading= Peak loading+ Infiltration = I4400 gpd + 480 gp d = I4880 gpd Flow in cubic feet per second =flow in gallons per day* A* B Where: A= 0.13368 cubic feet per gallon B = 0.00001157 days per second Flow in cubic feet per second (cfs) = 14880 gpd * 0.13368 * 0.00001157 = 0.0230 cfs According to Manning Pipe Theory, an 6" line graded at 0.6% can carry 0.436 cfs. where: Q = (1.49 / n) *A* R 2/3 * 5 0.5 Q =flow in cubic feet per second (cfs) n = Manning's roughness coefficient n = 0.013 for cast iron pipe A = area of pipe in square feet A= nd2 /4 A= n * (0.5)2 I 4 = 0.19635 R = hydraulic radius = A I P where: A = area of pipe in square feet P = wetted perimeter = n * diameter p = 1t * 0.5 = 1.5708 R= 0.19635 I I.5708 = 0.125 S = slope of pipe = 0.006 Q = (1.49 I 0.013) * 0.19635 * 0.1252 13 * 0.006°·5 Q = 0.436 cfs Since the ratio of loading to capacity is 0.0230/0.4360 = 0.053, the resulting velocity (from design tables) will be 0.513 of full flow velocity. Full flow velocity is calculated as follows: V =QI A fu ll Where: v fu ll = full flow velocity Q = full flow capacity in cfs = 0.436 cfs A= area of pipe in square feet= 0.19635 ft2 v,u11 = 0.436 I 0.19635 = 2.22 ft/ sec The resulting velocity for a pipe flowing at 0.053 full, being 0.513 of full flow velocity, is thus: v 0.053full = 0 .513 * 2.22 ft/sec= 1.139 ft/sec The two 6" diameter sewer lines flow into an existing 8" diameter line at the existing manhole (on sheet Sl). A total of two manholes are required, and a standard distance of 500 feet or less between manholes is maintained throughout this project. Referenc e Design and Construction of Sanitary and Storm Sewers. Prepared by a joint committee of the American Society of Civil Engineers (ASCE) and the Water Pollution Control Federation (WPCF): 1969. ASCE -Manuals and Reports on Engineering Practice No. 37. WPCF -Manual of Practice No. 9. Engineering Report For \Vaterlrnprovernents To Block 14A, Southwood Valley -Section 19 College Station, Brazos County, Texas Prepared For: Tony Jones 44 75 Hicks Lane College Station, Texas 77845 Prepared By: GARRETT ENGINEERING *May, Engineering Report For \VaterlITiproveITients To Block 14A, Southwood Valley -Section 19 College Station, Brazos County, Texas Prepared For: Tony Jones 44 75 Hicks Lane College Station, Texas 77845 Prepared By: GARRETT ENGINEERING CONSUL DIG EMGINEBlllG & UUIO SlRVEYlllC 4444CARTERCREBCPAl«WAY, SUITE111-8RYAN, nxAS ma.(..,~ -c..,••~1114 *May, 1995 * ENGINEERING REPORT for WATER IMPROVEMENTS to Block 14A, Southwood Valley -Section 19 College Station, BRAZOS COUNTY, TEXAS Block 14A of Southwood Valley -Section 19 is situated adjacent to Summit Street, between Southwood Drive and Hilltop Drive in Southwood Valley, College Station, Brazos County, Texas. Block 14A consists of 4 lots, established within the bounds of a 1.64 acre tract. Additionally, the project is partially surrounded by developed property, but future expansion of the proposed facilities will likely not be necessary. Soils within the area have shown historically to be quite stable. No faults exist within the project area, and no stability problems are foreseen, other than those caused by the expansive clays typical of Brazos County. Water needs are met with a combination of 2" diameter and 1 1 /2" diameter Type "K" copper service line. Water line "A" is a 2" diameter line that ties into the 6" diameter line that runs parallel to Summit Street, and crossed under Summit Street (55.0 ft.) to the lot line between Lot 2R and Lot 3R (sheet W-1). Water line "B'' is a 1 1 /2" diameter line that ties into the 6" diameter water line and crosses (55.0 ft.) under Summit Street to Lot 4R (sheet W-1). Water service to Lot 1 R comes from a 5 ft. long, 1 1 /2" diameter Type "K" copper service line that ties into the existing 8" water line that runs parallel to Southwood Drive. The meter loading was calculated to be 0.625 gallons per minute (gpm). This loading is calculated by considering a 4-plex on each lot, with each single unit having 3 bedrooms. One resident is assumed for each bedroom, with 100 gallons per day (gpd) assumed for each resident to get the daily loading factor. The daily loading is multiplied by 3 to the maximum loading per meter. These calculations are shown below: Daily loading = 3 residents per unit * 100 gpd per resident = 300 gpd = 0.208 gpm Peak loading = Daily loading * 3 = 300 gpd * 3 = 900 gpd = 0.625 gpm Total loading = Peak loading = 0.625 gpm Engineering Report For Sanitary Sewer Improvements To Block 14A, Southwood Valley -Section 19 College Station, Brazos County, Texas Prepared For: Tony Jones 44 75 Hicks Lane College Station, Texas 77845 Prepared By: GARRETT ENGINEERING CONSUL TDIG EHGINEERIHG & LAND SURVEYING 4444CARTER CREEK PAAJ<WAV, SUITE 1DI. BRYAN, TEXAS nao2. (409) 141-2111 . (4119) 84'-3094 *March, 1995 * ENGINEERING REPORT to accompany the replat of Block 14A, Southwood Valley -Secti on 19 College Station, BRAZOS COUNTY, TEXAS Block 14A of Southwood Valley -Section 19 is situated adjacent to Summit Street, between Southwood Drive and Hilltop Drive in Southwood Valley, College Station, Brazos County, Texas. Block 14A c onsists of 4 lots, established within the bounds of a 1.64 acre tract. Additionally, the project is partially surrounded by developed property, but future expansion of the proposed facilities will likely not be necessary. Soils within the area have shown historically to be quite stable. No faults exist within the project area, and no stability problems are foreseen, other than those caused by the expansive clays typical of Brazos County. Sanitary sewer needs are met by two separate 6" diameter P.V.C. SOR. 26-3034 sanitary sewer lines that run parallel to Summit Street, 8 feet off of the back of curb. Sanitary sewer line "A" (on sheet Sl). begins at the existing manhole (near the lot line between Lots 2R and 3R) and runs southwest from station O+OO to station 1+25.73, at a grade of 0.60%. Sanitary sewer line "B'' (on sheet Sl) begins at the existing manhole and runs northeast from station 0+00 to station 1+50.73 , at a grade of 0.60%. The pipe loading was calculated to be 0.023 cubic feet per second (cfs). This loading is calculated by considering a 4-plex on each lot, with each single unit having 3 bedrooms. One resident was assumed for each bedroom, totaling 12 residents per lot. A loading of 100 gallons per day (gpd) was assumed for each resident to get the daily loading factor. The daily loading is multiplied by 3 to get the peak loading and 10% of the daily loading accounts for infiltration. The infiltration is added to the peak loading to calculate the total loading. These calculations are shown below: Daily loading = 4 lots* 12 residents per lot* 100 gpd per resident = 4800 gpd Peak loading = Daily loading * 3 = 4800 gpd * 3 = 14400 gpd D,r);'.Y o~ /t six oi' /-l. (Jn/f~ Cf }'11Dte. COIA ;;e,.,,..tve ( (> r~5iltvik/uni) //J vwi to-er 0\ Infiltration = Daily loading* 0.10 he "'ear t/ or 5 5J-1ce = 4800 gpd * 0.10 rYlClj J, I 3 ~ 480 gpd '1 r~ k /wc11"'j ,f,;d,,r 0: Total loading = Peak loading + Infiltration l,,v-l'l 5 v5t) q "'j /l b /vte = 14400 gpd + 480 gpd 1/ 1 J r = 14880 gpd OttY: //Ylore.. ft1eiYl qaer<Pife i 0 t / f/0 ., 1 -/-l/5 5 £oJJ be ;pr1 Lo0)1AJ ~" __-t, .g" /,,~ {al7/,~ Flow in cubic feet per second = flow in gallons per day * A * B Where: A = 0.13368 cubic feet per gallon B = 0.00001157 days per second Flow in cubic feet per second (cfs) 148 ~ * 0.13368 * 0.00001157?\ = 0.0230 cfs 1; . / _....-1 1 ( nl n J' 6J /t-t 0 1 /1-l/iCf11/f s v Ot-<1 "\--{o(;{,I cjo ~( f[ ii V O :; I According to Manning Pipe Theory, an m l!ne graded at 0.6% can carry 0.436 cTu. ~ Q = (1.49 I n) *A* R 2 /3 * s o.5 where: Q =flow in cubic feet per second (cfs) .-/'..} n = Manning's roughness coefficient ~1 oZ 3 ~ C ~fif~' Z e.-p n = 0.013 for cast iron pipe l/• ~ A= area of pipe in square feet ~~ ~I) ~: :d:;i5l' I 4 = 0.19635 /?' ed!: (1 11 t,A'l.e.. R = hydraulic radius = A I P ~ ~ ;"\ where: l .,..lf lf,'''{S") ( A = area of pipe in square feet p = wette erimeter = 7t * diameter /;e fl A (, P = n * . -1. Cl I I S'1 / /vte tof' /'f b ~ R = 0.19635 / 1.5708 = 0.125 /tfou/O. / _ , ::::- S =slope of pipe= 0.006 U•Jer sf""'~ ~1Wil'1 r re-. L Q = (1.49; 0.013) • 0.19635 • 0 .1252 13 • 0.006°·5 f2tJ. l 1"1.e i / --, Q = 0.436 cfs (/ t>fi.'-'t '> 0 Since the ratio of loading to capacity is 0.0230/0.4360 = 0.053, the resulting velocity (from design tables) will be 0.513 of full flow velocity. Full flow velocity is calculated as follows: V =QI A fu ll Where: vfull = full flow velocity Q = full flow capacity in cfs = 0.436 cfs A = area of pipe in square feet = 0.19635 ft 2 Vruu = 0.436 I 0.19635 = 2.22 ft/ sec The resulting velocity for a pipe flowing at 0.053 full, being 0.513 of full flow velocity, is thus: v0.053full = 0.513 * 2.22 ft/sec= 1.139 ft/sec The two 6" diameter sewer lines flow into an existing 8" diameter line at the existing manhole (on sheet Sl). A total of two manholes are required, and a standard distance of 500 feet or less between manholes is maintained throughout this project. Reference D esign and Construction of Sanitary and Storm Sewers. Prepared by a joint committee of the American Society of Civil Engineers (ASCE) and the Water Pollution Control Federation (WPCF): 1969. ASCE -Manuals and Reports on Engineering Practice No. 37. WPCF -Manual of Practice No. 9. Engineering Report For \Vater!Inproveinents To Block 14A, Southwood Valley -Section 19 College Station, Brazos County, Texas ,, . \ . ' ' \ Prepared For: / Tony Jones 44 75 Hicks Lane College Station, Texas 77845 ,, Prepared By: GARRETT ENGINEERING CONSUi.. TINC BICLIWOG & LAllD llRVEYalc "'4CARml Cll!BC PAMWAY, SUITf 'la· IRYAll, 1IXAS 11182 • (411) M&.2111 • (411) 141-DM *April, 1995 * Engineering Report For \Vaterlrnprovernents To Block 14A, Southwood Valley -Section 19 College Station, Brazos County, Texas Prepared For: Tony Jones 44 75 Hicks Lane College Station, Texas 77845 Prepared By: GARRETT ENGINEERING *April, 1995 * ENGINEERING REPORT for water improvements to Block 14A, Southwood Valley -Section 19 College Station , BRAZOS COUNTY , TEXAS Block 14A of Southwood Valley -Section 19 is situated adjacent to Summit Street, between Southwood Drive and Hilltop Drive in Southwood Valley, College Station , Brazos County, Texas. Block 14A consists of 4 lots, established within the bounds of a 1.64 acre tract. Additionally, the project is partially surrounded by developed property, but future expansion of the propo sed facilities will likely not be necessary. Soils within the area have shown historically to be quite stable. No faults exist within the project area, and no stability problems are foreseen, other than those caused by the expansive clays typical of Brazos County. Water needs are met with a combination of 2" diameter and 1 1 /2" diameter Type "K" copper service line. Water line "A" is a 2" diameter line that ties into the 6" diameter line that runs parallel to Summit Street, and crossed under Summit Street (55.0 ft.) to the lot line between Lot 2R and Lot 3R (sheet W-1). Water line "B'' is a 1 1 /2" diameter line that ties into the 6" diameter water line and crosses (55 .0 ft.) under Summit Street to Lot 4R (sheet W-1). Water service to Lot 1 R comes from a 5 ft. long, 1 1 /2" diameter Type "K" copper service line that ties into the existing 8" water line that runs parallel to Southwood Drive . The meter loading was calculated to be 0.625 gallons per minute (gpm). This loading is calculated by considering a 4-plex on each lot, with each single unit having 3 bedrooms. One resident is assumed for each bedroom, with 100 gallons per day (gpd) assumed for each resident to get the daily loading factor. The daily loading is multiplied by 3 to the maximum loading per meter. These calculations are shown below: Daily loading = 3 residents per unit * 100 gpd per resident = 300 gpd = 0.208 gpm I >A Jl ~ Peak loading = Daily loading * 3 Dr?iJe"'-CYf M-°7 Ov· Ive = 300 gpd * 3 r / COVt 5etl/6'-+, = 900 gpd = 0.625 gpm o{' Ufl 1l1 a ~t>~ I / -/-woJd b 1 o-\ ~ /Cfe1Ats ;v~11 I Total loading = Peak loading Y1vyV/ e r-. 510cc "' pe~ /:-= 0.625 gpm J. Lj tl)f "J , I I fd,t I l , l Vl j 11\A~ accov~ f ~ote · P 1(¥;1J;,7 fc o; J ,<.;+ YJP•r j (le_ ti Setv!~ c,e_ tulhf I I r,e t1( ('vf,t t* / / J, uer- tN1 CA. -f ../-ht 7 ~i o0d'1 k. cross if" or pviorC:_ ~ 207pi4'' J , JI /;e a Je7tfa -fli 6 5"eiMt-"'1a1111 · I tt'.J,9'1 ~I ca. &I/ / DRAINAGE CO UTATIONS for Summit Four-Plexes being LOTS 1R-4R of a REPLAT of BLOCK 14A Southwood Valley -Section 19 College Station, Brazos Coun ty, Texas Prepared for Tony Jones 4475 Hicks Lane College Station, Texas 77845 Prepared bv: ·'-· Garrett Engineering I 4444 Carter Creek Parkway -Suite 108 ~ "'""'' ' \ Bryan, Texas 77802 ---~~ ~-~· .~ ' 1 Telephone: (409) 846-2688 j'1...~···~"· ·:. ~...'',. ,,"f: c.-<:\ •'~ ,,_. _,;_\ .. ~ *March, 1995 * ®~ ~ ().. dv~IWA-fl'.tltf_ ~ ~J.gr Q ~ J. ~ it~ ,__..,..--7h c r~t e>pmc.-A- DRAINAGE COMP for ~AReplatof Bio V-Southwood Vall ey - College Station, Brazos * April , 199: SUMMAR The proj ect is situated off F.M. 2818 between Southwoo Subdivision, College Station , Brazos County, Texas. B consists of 4 lots being established wiU1in th e bound s of tl1( ({Q ~ m~p (S nef 1-f) ctvJ e..J fVI fh,·s ~86' '/£--/pv f-I VJ {YI e,, 1)c Vtrr 7v ~; tbJ · The total drainage area tributary to th e project is 1.94 acres. The pre-development run-off coefficient was estimated to be 0.40, while taking into account typical residentia l s ite improvements would resu lt in a post-development run-off coefficient of 0.63. Detention facilities will be constructed at various locations of th e property to ensure th e collection of n ecessary runoff volumes and make use of practical drainage patterns. Three detention ponds are designed witll capacity to facilitate up to and includin g tlle 100-year stonn event, and discharge at a rate less tl rnn tll e current pre-development peak di sc harge rate. The detention ponds will intercept, store and m eter run-off from 1.20 acres of tl1 e proj ect. The run -off generated on U1e remaining 0.74 acres will "free- tlow" across tl1e project site unm e te red off tll e property . These report calculations are summarized according to tlle following methodology . (The report is divided into 3 sections corresponding to Ponds A through C.) Beginning on page 1 of each section, based on the total tributary drainage area of the proj ect (being 1.94 acres for th e whole tract, but re flecting tlle specific drainage area for th e corresponding pond in tllat section), tlle pre-development run-off coefficient (being assumed a t 0.40), and a minimum time of concentration of 10 minutes, tlle relative pre-development peak di scharge rate ("Q") was detennined. The Rational Method was utilized to compute the estimated peak pre-development discharge rates. The e quation tllat re presents the Rational Method is as follows: Q = CIA. "Q" is tlle peak discharge rate in cubic feet pe r second, "C" is the run-off coefficient, assumed to be 0.40 in tl1e pre-development condition, "I" is tl1e storm intensity in inches p e r hour, and "A" is tlle area of tl1 e drainage basi n in acres. Computations on page 2 are based on tl1 e re lative tributary ru-ea, tlle post-development run-off coefficient of 0.63 (being weighted according to tl1 e re lative amounts of pervio us and impervious surface area), a minimum time of concentration of 10 minutes, to yield tl1e relative pre-development peak di scharge rate ("Q") (ass uming tlle same minimum time of concentration of 10 minutes). The Rational Method was again utilized to compute tl1e es timated p eak post-development discharge rates. The equation that represents the Rational Method is as follows: Q = CIA, where; "Q" is the peak di schru-ge rate in cubic feet per second. The "C" variable is tl1 e run-off coefficient. (In tlle post-developme nt condition "C" is ass umed to be 0.63.) "I" represe nts tl1 e rainfall inten s ity in inches p e r hour, and similarly "A" is tlle area of tlrn basin in acres. Comparison of tl1 e peak pre-development discharge rate to tll e post-development discharge rate is include d in tll e report to aid tll e designer in estab li s hing a preliminary "target" of detention volume required. This preliminary estimate is determined as the volume difference gene rated between th e pre - deve lopment and post-development hydrographs. (See p ages 9-11 for pre-development and post- development hydrograp hs.) Please n ote tll at tl1e post-deve lopme nt hydrograph shown on tlles e smne graphs ass umes no detention and re fl ects tl1e "worst-case " scenario that all run-off is allowed to free-flow. Pa ges 3 and 4 prov ide infonn a ti on co ncernin g th e pos t-d e velopm ent run-off th at is n o t routed th ro ugh th e d ete nt io n fa cility ("free-fl o w") as well as th e pos t-devel opm ent run -off that is ro uted throu g h th e de tention faci lit y and re ta in ed o n s ite . Page 5 a nd page 6 are ta bulation s of th e pre-d e velopm ent and th e pos t-d e ve lopm ent hydro g raph s based on th e co mputation s perfo nned on page 1 and page 2 . The pos t-d e velopment hydrograph ass um es no de tenti on to facili tate direct compariso n in th e pre -and post-de velo pment condition s. Page 7 and page 8 are tabulation s of th e pos t-d evelopm ent hydrograph for run -off directed through th e d etentio n fa cility and th e po s t-d evelopment hydro graph fo r "free-flow" from th e proj ect s ite . Compu ta ti o ns on p age 4 de termin e th e actual peak pos t-d eve lopment "infl ow" rate suppli ed to th e proposed de tention faci lity . From thi s "inflow" rate and the tim e of concentra ti o n (10 minutes minimum), a h yd rograph as tabul a ted on p age 8 is d eri ve d . The h ydro graph is tri angular in sha pe and is based o n the stan dard SCS unit h ydro g raph with tim e to peak se t eq ual to th e tim e of concentr ation and th e total tim e base set at 3.00 tim es th e tim e of co ncentra tion . Pl ease note th a t a 30 minute to tal s torm event duration was util ized exclu s ively throu g hout U1i s report du e to th e relati ve s mall size o f th e proj ect. Hav in g derived th e preliminary volum e requireme nts and "all owabl e p eak" di scharg e rate, it is no w poss i ble to de si gn th e final de tention facility and o utl e t contro l s tructure. Page 12 presents a data. tabul atio n and a dep U1 ve rsus volum e g raph of U1 e de tention facility . The m ax imum de pth of th e p ond was set acc ordin g to th e required ca pacity and U1 e s pecified freeb oard requ irements outlined in city o rdin ances. Page 13 s uppli es a tabula tion and a ratin g curv e fo r th e propose d o utl et control s tru c ture. A m e terin g pipe was chosen for th e o utl e t contro l s tru c ture du e to de pU1 ve rses d ischarge ra ti o characteri s ti cs assoc ia ted with th e anti c ip a ted sh al lo w headwate r de pth . An ultimate s torage de pth of 1.5 fee t is av a ila bl e du e to th e physical geo me try of th e pond . However, even a t 100-year s tonn co ndition s, depth s of less th an 1.0 feet are anti c ip ated . P age 14 presen ts a tabul ation of th e relations hip between di sch arge from th e detention fac ility and th e dim e ns ionl ess qu an tity 2 S/t-O . Al so presented is a Stora ge Ind ication Curve fo r th e detenti on fa cility based on Ul e aforem enti on ed ph ys ic al charac teri s tics of tl1 e de tention pon d, s to rage volume, inflow h yd rograp h, and ratin g curve for Ul e outle t s tructure. The s torage indication curve as shown on page 12 is a g raph ical soluti on to U1 e equ a ti on presented in th e "D ra in a ge Poli c y And Des ign Standards" as foll ows: 2s 1 (11 +Ii)+(--------------- dt 2s 2 -01) = (-----------------+ 0 2) dt Page 15 t11rou g h page 26 present s imul ation s of tl1 e 2, 5, 10, 2 5, 50, and 100 year s torm events . The fir s t p age of each s torm s imulation represents th e ta bul ated data. fo r tl1 e storm e ve nt. The m ax imum de pili ac hi eved in tl1 e deten ti on pond durin g each s imul a ti on is sho wn below as is tll e time a t durin g which Uli s m ax imu m d e ptll occurs from tll e on set of Ul e s to rm ev ent. Th e calcul a ted peak di sc harge ra te co rres po nding to thi s depili ove r sam e p eriod is al so shown bel ow. Additi onal ly , tll e m a ximum wa te r sur face elevation ac h ieved durin g each event a nd Ul e maximum peak di sch arge durin g each event are li sted be low. The seco nd page of each s tonn s imul a tio n re presents th e pre-d evelo pm ent h yd rograph , tl1 e post-developme nt hydrog ra ph (w iU1 no d etenti on ), U1 e pos t-develo pm ent hyd rograph as ro uted Ulrou gh th e deten tio n po nd , ru1d pos t-develop me nt "free-fl o w" hydrog raph fo r each s torm eve nt. Page 27 tJ1rough page 32 provide total inflow/outflow hydrographs for ilie 2, 5, 10, 25, 50 and 100-year pre-d e velopment and post-development stonn events. It can be determined from iliese same hydrographs iliat ilie post-development peak discharge rates have been minutely decreased from iliose peak pre- development discharge rates due to U1e incorporation of ilie detention facility in ilie post-development condition. Total po s t-development peak discharge rates from ilie detention pond outlet control structure ancl project site are kept less ilian ilie pre-development peak discharge rates clue to ilie incorporation of ilie proposed detention facilities . Subsequent peak post-development discharge velocities projected to be wiiliin manageable limits. DRAINAGE COMPUTATIONS for Detention Pond "A" -Summit Street Four-Plexes being Lots 1R-4R Of A Replat Of Block 14A Southwood Valley -Section 19 College Station, Brazos County, Texas Prepared for Mr. Tony Jones 4475 Hicks Lane College Station, Texas 77845 Prepared bv: Garrett Engineering 4444 Carter Creek Parkway -Suite 108 Bryan , Texas 77802 Telephone: (409) 846-2688 * April, 1995 * Detention Pond Storage Volumes as Percent of Maximum Volume 100°/o 90°/o 80°/o 70°/o Q) E :J 0 60°/o > E :J E ')( 50°/o 0 :E -0 -40°/o c Q) 0 .... Q) 0... 30°/o 20 °/o 10°/o O°lo 2-year 5-year 10-year 25-year 50-year Design Storm Storm Simulation Synopsis 2-ear 5-ear 10-ear 25-ear Storm Depth 0.58 0.65 0.70 0.76 Storm Elevation 324.08 324 .15 324 .20 324 .26 324 .33 324 .36 Storm Volume 660 850 990 1180 1389 1472 Maximum Capacity 4052 4052 4052 4052 4052 4052 Percent of Capacity 16% 21 % 24 % 29 % 34 % 36% 33 Detention Pond Storage Volumes as Percent of Maximum Volume l 00% 90% 80% 70% Q) E :J 0 60% > E :J E ')( 50% 0 ::E -0 -40% c Q) 0 ... Q) ll.. 30% 20% 10% 0% 2-year 5-year 10-year 25-year 50-year De si gn Storm Storm S im ulat ion Synop s is 2-ear 5-ea r 10-ear 25-ear Storm Depth 0.55 0 .62 0 .67 0 .72 Storm Ele vation 325 .35 325.42 325.47 325 .52 Storm Vo lume 1213 1544 1784 2086 2385 Maximum Capacity 632 1 6321 6321 6321 6321 Percent of Capacity 19 % 24% 28% 33% 38% 40% 33 Determine Total Pre-Development Peak Storm Water Discharge Rates Tributary Area ("A"): 0.53 Acres Pervious Area : 0.52 Acres Impervious Area : 0.01 Acres Run-Off Coefficient ("Cwt "): 0.41 Time Of Concentration ("T/c"): Woodlands: Low Elevation : High Elevation : Distance (Feet): Slope (%Grade): Veloc ity ("Vw"): Time : Pastures: Low Elevation : High Elevation: Distance (Feet): Slope (%Grade): Velocity ("Vp"): Time : Pavements: Low Elevation : High Elevation : Distance (Feet): Slope (%Grade): Velocity ("Vpave"): Time: Total Travel Time : Hourly Intensity Rates ("I "): 2-Year: 6.33 5-Ye ar: 7.69 10-Year: 8.63 25-Year: 9.86 50-Year : 11 .15 100-Year: 11.64 Peak Di scharge Rate ("Q "): 2-Year: 1.38 5-Year: 1.68 10-Year: 1.88 25-Year: 2 .15 50-Year : 2.43 100-Year: 2.54 c = 0.40 C = 0.98 0.00 0.00 0.00 0.00 0.00 Feet/ Second 0.00 Minutes 0.00 0.00 0.00 ---- 0.00 ___,., 0.00 Feet I Second 0.00 Minutes h- 0.00 0.00 0.00 0.00 0.00 Feet I Second 0.00 Minutes 10.00 Minutes Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second ~ ~~ Determine Post -development Peak Storm Water Dischar e No Detention Tributary Area ("A"): 0.53 Acres Pervious Area : 0.32 Acres Imperviou s Area : 0 .21 Acres Run-Off Coefficient ("Cwt"): 0.63 Time Of Concentration ("T/c"): 1 O Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 6.33 5-Ye ar: 7.69 10-Year : 8.63 25-Year: 9.86 SO-Year: 11 .15 100-Year: 11.64 c = 0.4 0 C= 0.98 Inc hes I Ho u r In ches I Hou r Inches I Ho u r Inc hes I Hour Inc hes I Hour In c hes I Hour Peak Discharge Rat e ("O"): 2-Year: 2.11 Cubic Feet I Second 5-Year: 2.57 Cu bic Feet I Second 10-Year : 2.88 Cub ic Feet I Second 25-Year : 3 .29 Cubic Feet I Second 50-Year: 3.72 Cub ic Feet I Second 1 OD-Year: 3 .89 C ub ic Feet I Second Comparison Of Predevelopment And Post-develo ment Peak Dischar e Rates Predevelopment Post-Development Increase 2-Year: 1 .38 Ft3/sec 2.11 Ft3/sec 0.73 Ft3/sec 5-Year: 1.68 Ft3/sec 2.57 Ft3 /sec 0.89 Ft3/sec 10-Year : 1.88 Ft3/sec 2.88 Ft3 /sec 1 .00 Ft3/sec 25-Year : 2.15 Ft3/sec 3.29 Ft3/sec 1 .14 Ft3/sec 50-Year: 2.43 Ft3/sec 3.72 Ft3/sec 1 .29 Ft3/sec 100-Year: 2.54 Ft3/sec 3 .89 Ft3/sec 1 .35 Ft3/sec Prel iminary Determination Of Detention Pond Volume 2-Year : 0.73 Ft3/sec x (3 0 Min. x 60 Sec . I 2 ) = 66 0 Cu bic 5-Year: 0.89 Ft 3/sec x (3 0 Min. x 60 Sec . I 2 ) = 803 Cu bic 10 -Year : 1.00 Ft 3/sec x (3 0 Min . x 60 Sec . I 2 ) = 901 Cu bic 25 -Year : 1.14 Ft3/sec x (3 0 Min. x 60 Sec . I 2 ) = 1 ,03 0 C ub ic 50-Year : 1.29 Ft3/sec x (3 0 Min . x 60 Sec . I 2 ) = 1,164 Cubic 100-Year: 1 .35 Ft3/sec x (3 0 Min . x 60 Sec . I 2 ) = 1 ,215 Cubic 2 Fee t Feet Feet Feet Feet Feet Determine Post-Development "Free-Flow" Peak Storm Water Discharge Tributary Area ("A"): _Qg4..--Acres Pervious Area: 0.12 Acres Impervious Area: 0.12 Acres Run-Off Coefficient ("Cwt"): 0.69 Time Of Concentration ("T/c"): 10 Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 6.33 5-Year: 7.69 10-Year: 8.63 25-Year: 9.86 50-Year: 11.15 100-Year: 11 .64 Peak Discharge Rate ("Q"): 2-Year: 1.05 5-Year: 1.27 10-Year: 1.43 25-Year: 1.63 50-Year: 1.85 100-Year: 1.93 3 C= 0.40 C= 0.98 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Determine Post-Development Flow Into Detention Pond Tributary Area ("A"): 0.29 Acres Pervious Area : 0.20 Acres Impervious Area: 0.09 Acres Run-Off Coefficient ("Cwt"): 0.58 Time Of Concentration ("T/c"): 10 Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 6.33 5-Year: 7.69 10-Year: 8.63 25-Year: 9.86 50-Year: 11 .15 100-Year: 11 .64 Peak Discharge Rate ("Q"): 2-Year: 1.06 5-Year: 1.29 10-Year: 1.45 25-Year: 1.66 1.88 1.96 4 c = 0.40 C= 0.98 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inc Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second ~~ ~;f;~ ~ 4.00 3 .50 3.00 ....... "O c 0 0 2.5 0 <I> (/) Q) a... -<I> <I> u.. 2.00 0 :0 ::::> u ....., ~ 1.5 0 0 E ::::> 0 1.00 0.50 0.00 0 Inflow/Outflow Simulation 100-Year Storm Event I I I I I I • I I ' I I I I I I .• . I I 5 Pre----- Developme nt Hydr ograph I ' I I . ' ' . ' I , , , I J 10 ' ' ' ' ' ' ' ' .. ' ' ' ' 15 ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' 20 Time (Minutes) Post-Post- Developme Developme nt Outflow nt Outflow Hydrograph With Withou t Detention Detention 26 ' "' ' ' ' ' ' ' 25 ........ 30 Post- Developme nt "Free- Flow" Detention Pond Sto rage Vol u mes as Percent of Maximum Volume 100% 90% 80% 70% Q) E :::> 0 60% > E :::> E ")( 50% 0 :E -0 -40% c Q) 0 .... Q) 0... 30% 20% 10% 0% 2-year 5-year 10-year 25-year 50-year Design Storm Storm Simulat ion Synopsi s 2-ear 5-ear 10-ear 25-ear 50 -ear 100-ear Storm Depth 0 .5 0 0 .54 0.56 0.60 0 .64 0 .66 - Storm Elevat ion 3 25.00 3 25.04 3 25 .06 32 5.1 0 325 .14 3 25 .1 6 Storm Vo lume 628 70 0 911 1073 1249 1320 Maximum Capacity 4634 4634 4634 4634 4634 4634 Percent of Ca pacity 14% 15% 20% 23% 27 % 28% 33 ~ ~11~- ~ DRAINAGE COMPUTATIONS for Summit Four-Plexes being LOTS 1R-4R of a REPLAT of BLOCK 14A Southwood Valley -Section 19 College Station, Brazos County, Texas Prepared for Tony Jones 4475 Hicks Lane College Station, Texas 77845 Prepared bv.· Garrett Engineering 4444 Carter Creek Parkway -Suite 108 Bryan, Texas 77802 Telephone: (409) 846-2688 Determine Total Pre-Development Peak Storm Water Discharge Rates Tributary Area ("A"): 1.94 Acres Pervious Area : 1.90 Acres Impervious Area : 0.04 Acres Run-Off Coefficient ("Cwt"): 0.41 Time Of Concentration ("T/c"): Woodlands: Low Elevation : High Elevation: Distance (Feet): Slope (% Grade): Velocity ("Vw"): Time : Pastures: Low Elevation : High Elevation: Distance (Feet): Slope (%Grade): Velocity ("Vp"): Time: Pavements: Low Elevation : High Elevation : Distance (Feet): Slope (%Grade): Velocity ("Vpave"): Time: Total Travel Time : Hourly Intensity Rates ("I"): 2-Year: 6.33 5-Year: 7 .69 10-Year: 8 .63 25-Year: 9.86 50-Year: 11 .15 100-Year: 11 .64 Peak Discharge Rate ("Q"): 2-Year: 5.06 5-Year: 6.15 10-Year: 6.90 25-Year: 7 .88 50-Year: 8 .91 100-Year: 9.30 C= 0.40 C= 0 .98 0.00 0.00 0.00 0.00 0 .00 Feet I Second 0 .00 Minutes 0.00 0.00 0 .00 0.00 0.00 Feet I Second 0.00 Minutes 0 .00 0.00 0.00 0.00 0 .00 Feet I Second 0.00 Minutes 10.00 Minutes Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Determine Post-development Peak Storm Water Dischar e No Detention Tributary Area ("A "): J Pervious Area : 1.13 Acres Impervious Area: 0.81 Acres Run-Off Coefficient ("Cwt"): 0.64 Time Of Concentration ("T/c "): 1 O Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 6.33 5-Year: 7.69 10 -Year: 8.63 25-Year: 9.86 50-Year : 11.15 100-Year: 11 .64 Peak Discharge Rate ("O"): 2-Year: 7.88 5-Year: 9.58 10-Year: 10.76 25-Year: 12.29 50-Year: 13 .89 100-Year: 14.50 Comparison Of Predevelopment And Post-development Peak Discharge Rates C= 0.40 ' C= 0 .98 ~ Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Predevelopment Post -Development Increase 2-Year: 5.06 Ft3/sec 7.88 Ft3 /sec 5-Year: 6.15 Ft3/sec 9.58 Ft3 /sec 10-Year: 6.90 Ft3/sec 10 .76 Ft3 /sec 25-Year: 7.88 Ft3/sec 12 .29 Ft3/sec 50-Year: 8.91 Ft3/sec 13 .89 Ft3 /sec 100-Year: 9 .30 Ft3/sec 14.50,/sec Preliminary Determination Of Detention Pond Volume 2-Year: 5-Year: 10-Year: 25 -Year : SO-Year : 100-Year: 2.83 Ft3/sec x (30 Min . x 60 Sec. I 2 ) = 3.44 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 3 .86 Ft3/sec x (30 Min. x 60 Sec . I 2 ) = 4.40 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 4 .98 Ft3/sec x (30 Min. x 60 Sec . I 2 ) = 5.20 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 2 2.83 Ft3 /sec 3.44 Ft3/sec 3.86 Ft3/sec 4.40 Ft3/sec 4 .98 Ft3/sec 5.20 Ft3/sec 2,543 Cubic 3,092 Cubic 3,471 Cubic 3,964 Cubic 4,481 Cubic 4,678 Cubic Feet Feet Feet Feet Feet Feet Determine Post-Development 11 Free-Flow 11 Peak Storm Water Discharge Tributary Area ("A"): 1.44 Acres Pervious Area: 0.85 Acres Impervious Area : 0.59 Acres Run-Off Coefficient ("Cwt"): 0.64 Time Of Concentration ("T/c"): 10 Minutes (Min)/ Hourly Intensity Rates ("I "): 2-Year: 6 .33 5-Year: 7.69 10-Year: 8.63 25-Year: 9.86 50-Year: 11.15 100-Year: 11.64 Peak Discharge Rate ("Q"): 2-Year: 5 .81 5-Year: 7.06 10-Year: 7 .93 25-Year: 9 .05 50-Year: 10.24 100-Year: 10.69 3 C= 0.40 ' C= 0 .98 J Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second - Determine Post-Development Flow Into Detention Pond Tributary Area ("A "): 0.50 Acres Pervious Area : 0 .29 Acres Impervious Area: 0 .21 Acres Run-Off Coefficient ("Cwt"): 0 .64 Time Of Concentration ("T/c"): 10 Minutes (Min) J Hourly Intensity Rates ("I"): 2-Year: 6.33 5-Year: 7 .69 10 -Year: 8.63 25-Year: 9.86 50-Year: 11 .15 100-Year: 11 .64 Peak Discharge Rate ("Q "): 2-Year: 2.04 5-Year: 2.48 10-Year: 2.78 25 -Year: 3 .17 50-Year: 3.59 100-Year: 3 .75 4 C= 0.40 ' C= 0.98 J Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Pre-Development Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year {Minutes} Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.51 0.61 0.69 0.79 0.89 0.93 2 1.01 1.23 1.38 1.58 1.78 1.86 3 1.52 1.84 2.07 2.36 2.67 2.79 4 2.02 2.46 2.76 3.15 3.56 3.72 5 2.53 3.07 3.45 3.94 4.45 4.65 6 3.03 3.69 4.14 4.73 5.35 5.58 7 3.54 4.30 4.83 5.52 6.24 6.51 8 4.04 4.92 5.52 6.31 7.13 7.44 9 4.55 5.53 6.21 7.09 8.02 8.37 Peak=> C:.:10 5.06 6.15 6.90 _z.88 8.91~ 9.30 -11 4.80 5.84 6.56 7.49 8.46 8.84 12 4.55 5.53 6.21 7.09 8.02 8.37 13 4.30 5.23 5.87 6.70 7.57 7.91 14 4.04 4.92 5.52 6.31 7.13 7.44 15 3.79 4.61 5.18 5.91 6.68 6.98 16 3.54 4.30 4.83 5.52 6.24 6.51 17 3.29 4.00 4.49 5.12 5.79 6.05 18 3.03 3.69 4.14 4.73 5.35 5.58 19 2.78 3.38 3.80 4.33 4.90 5.12 20 2.53 3.07 3.45 3.94 4.45 4.65 21 2.28 2.77 3.11 3.55 4.01 4.19 22 2.02 2.46 2.76 3.15 3.56 3.72 23 1.77 2.15 2.42 2.76 3.12 3.26 24 1.52 1.84 2.07 2.36 2.67 2.79 25 1.26 1.54 1.73 1.97 2.23 2.33 26 1.01 1.23 1.38 1.58 1.78 1.86 27 0.76 0.92 1.04 1.18 1.34 1.40 28 0.51 0.61 0.69 0.79 0.89 0.93 29 0.25 0.31 0.35 0.39 0.45 0.47 30 0.00 0.00 0.00 0.00 0.00 0.00 5 Post-Development Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.79 0.96 1.08 1.23 1.39 1.45 2 1.58 1.92 2.15 2.46 2.78 2.90 3 2.36 2.88 3.23 3.69 4.17 4.35 4 3.15 3.83 4.30 4.91 5.56 5.80 5 3.94 4.79 5.38 6.14 6.94 7.25 6 4.73 5.75 6.45 7.37 8.33 8.70 7 5.52 6.71 7.53 8.60 9.72 10.15 8 6.31 7.67 8.61 9.83 11.11 11.60 9 7.09 8.63 9.68 11.06 12.50 13.05 Peak=> L10~ 7.8(! 9.58 --1<?_.]6 _ _12.2~13.89 14.5Q 11 7.49 9.10 10.22 11.67 13.19 13.78 12 7.09 8.63 9.68 11.06 12.50 13.05 13 6.70 8.15 9.14 10.44 11.80 12.33 14 6.31 7.67 8.61 9.83 11.11 11.60 15 5.91 7.19 8.07 9.21 10.42 10.88 16 5.52 6.71 7.53 8.60 9.72 10.15 17 5.12 6.23 6.99 7.99 9.03 9.43 18 4.73 5.75 6.45 7.37 8.33 8.70 19 4.33 5.27 5.92 6.76 7.64 7.98 20 3.94 4.79 5.38 6.14 6.94 7.25 21 3.55 4.31 4.84 5.53 6.25 6.53 22 3.15 3.83 4.30 4.91 5.56 5.80 23 2.76 3.35 3.76 4.30 4.86 5.08 24 2.36 2.88 3.23 3.69 4.17 4.35 25 1.97 2.40 2.69 3.07 3.47 3.63 26 1.58 1.92 2.15 2.46 2.78 2.90 27 1.18 1.44 1.61 1.84 2.08 2.18 28 0.79 0.96 1.08 1.23 1.39 1.45 29 0.39 0.48 0.54 0.61 0.69 0.73 30 0.00 0.00 0.00 0.00 0.00 0.00 6 Post-Development "Free-Flow" Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.58 0.71 0.79 0.91 1.02 1.07 2 1.16 1.41 1.59 1.81 2.05 2.14 3 1.74 2.12 2.38 2.72 3.07 3.21 4 2.32 2.83 3.17 3.62 4.09 4.27 5 2.90 3.53 3.96 4.53 5.12 5.34 6 3.49 4.24 4.76 5.43 6.14 6.41 7 4.07 4.94 5.55 6.34 7.17 7.48 8 4.65 5.65 6.34 7.24 8.19 8.55 9 5.23 6.36 7.14 8.15 9.21 9.62 Peak=> I 10 _5.81 7.06 1_93 9~QL-10.24 10.69 11 5.52 6.71 7.53 8.60 9.72 10.15 12 5.23 6.36 7.14 8.15 9.21 9.62 13 4.94 6.00 6.74 7.70 8.70 9.08 14 4.65 5.65 6.34 7.24 8.19 8.55 15 4.36 5.30 5.95 6.79 7.68 8.02 16 4.07 4.94 5.55 6.34 7.17 7.48 17 3.78 4.59 5.15 5.89 6.65 6.95 18 3.49 4.24 4.76 5.43 6.14 6.41 19 3.19 3.88 4.36 4.98 5.63 5.88 20 2.90 3.53 3.96 4.53 5.12 5.34 21 2.61 3.18 3.57 4.07 4.61 4.81 22 2.32 2.83 3.17 3.62 4.09 4.27 23 2.03 2.47 2.77 3.17 3.58 3.74 24 1.74 2.12 2.38 2.72 3.07 3.21 25 1.45 1.77 1.98 2.26 2.56 2.67 26 1.16 1.41 1.59 1.81 2.05 2.14 27 0.87 1.06 1.19 1.36 1.54 1.60 28 0.58 0.71 0.79 0.91 1.02 1.07 29 0.29 0.35 0.40 0.45 0.51 0.53 30 0.00 0.00 0.00 0.00 0.00 0.00 7 Post-Development Flow Routed Through Detention Pond Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.20 0.25 0.28 0.32 0.36 0.37 2 0.41 0.50 0.56 0.63 0.72 0.75 3 0.61 0.74 0.83 0.95 1.08 1.12 4 0.81 0.99 1.11 1.27 1.43 1.50 5 1.02 1.24 1.39 1.59 1.79 1.87 6 1.22 1.49 1.67 1.90 2.15 2.25 7 1.43 1.73 1.95 2.22 2.51 2.62 8 1.63 1.98 2.22 2.54 2.87 3.00 9 1.83 2.23 2.50 2.86 3.23 Peak=> I )O __ 2.04 2.48 __ 2.78 3.17 3.59 -11 1.93 2.35 2.64 3.01 3.41 3.56 12 1.83 2.23 2.50 2.86 3.23 3.37 13 1.73 2.10 2.36 2.70 3.05 3.18 14 1.63 1.98 2.22 2.54 2.87 3.00 15 1.53 1.86 2.08 2.38 2.69 2.81 16 1.43 1.73 1.95 2.22 2.51 2.62 17 1.32 1.61 1.81 2.06 2.33 2.43 18 1.22 1.49 1.67 1.90 2.15 2.25 19 1.12 1.36 1.53 1.75 1.97 2.06 20 1.02 1.24 1.39 1.59 1.79 1.87 21 0.92 1.11 1.25 1.43 1.61 1.69 22 0.81 0.99 1.11 1.27 1.43 1.50 23 0.71 0.87 0.97 1.11 1.26 1.31 24 0.61 0.74 0.83 0.95 1.08 1.12 25 0.51 0.62 0.69 0.79 0.90 0.94 26 0.41 0.50 0.56 0.63 0.72 0.75 27 0.31 0.37 0.42 0.48 0.54 0.56 28 0.20 0.25 0.28 0.32 0.36 0.37 29 0.10 0.12 0.14 0.16 0.18 0.19 30 0.00 0.00 0.00 0.00 0.00 0.00 8 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 2-Year Storm Even t -7 .00 +-----+---~--+-~~-+-----+-------t------; Cl) ll.. Qj Cl) LL. 0 "" 5.00 +-----+--1------7!......-----+------'"'""""--+-------t------; :0 -g 8 8 4 .00 +-----1------.,,C.----t---""""""'+-----"'k:-------t------; "' Cl) & Cl) 3.00 ,.._ __ _,_-t--,iL----,--l----+-----""-....,..--t--~:-----l-------l 5 .s::. 0 II) 0 0 5 10 15 20 25 Time (Minutes) ---Pre -Development Hydrograph ----Tota l Post-Development Hydrograph 10.00 -9 .00 Cl) ll.. 8.00 -Cl) Cl) 7.00 LL. 0 "" 6.00 ·-"O ..0 c :J 0 5.00 u 0 "' Cl) 4 .00 Cl) Cl) Ol -3.00 0 .s::. 0 2.00 II) 0 1.00 0 .00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 5-Year Storm Event 5 10 15 20 25 Time (Minutes) Pre-Development Hydrograph ----Post-Development Outflow Hydrograph Without Detention 9 30 30 12.00 ... Q) 10 .00 ll.. -Q) Q) 8 .00 LL. 0,.... ·-"O .0 c :::> 0 6 .00 () 0 ~ Q) Q) (I') O> 4.00 ... 0 .s::. 0 2 .00 II) 0 0 .00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 10-Year Storm Event 5 10 15 20 25 Time (Minutes) 30 ----Pre-Development Hydr ograph ----Post -Developm e nt Outflow Hydrogra p h With o ut Detention 14.00 ... 12 .00 Q) ll.. -Q) 10.00 Q) LL. 0,.... ·-"O 8 .00 .0 c :::> 0 () 0 6 .00 ~ Q) Q) Cl) O> ... 0 4.00 .s::. 0 II) 2 .00 0 0 .00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 25-Year Storm Event 5 10 15 20 25 Time (Minutes) 30 ----Pre-Development Hydrograph ----Post-D evelopm e nt Outflow Hydrogra ph With out Detenti o n 10 14 .00 ... 12 .00 Q) 0... -Q) 10 .00 Q) u. 0 ....... ·-"O 8 .00 .0 c ::::J 0 u 0 6 .00 ~ Q) Q) Cl) 0) ... 4 .00 0 ~ 0 II) 2 .00 i5 0 .00 0 Total Pre -Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 50-Year Storm Eve nt 5 10 15 20 25 Time (Minutes) 30 ---Pre-Development Hydrograph ----Post-D evelopment Outflow Hydrograph Without Detention ... Q) 0... -Q) Q) u. 0 ....... ·-"O .0 c ::::J 0 u 0 ~ G> G> Cl) 0) ... 0 ~ 0 II) i5 16 .00 14 .00 12 .00 10 .00 8 .00 6 .00 4.00 2 .00 0.00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 100 -Year Storm Event 5 10 15 20 25 nme (M inutes) ----Pre-Development Hydrograph ----Post-Develop ment Outflow Hyd rograph Without Detention 11 30 Detention Pond Deoth Vs. Volume Elevation Depth Volume (Feet) (Ft3) 324 .93 0.00 0 325 .00 0.07 11 325.75 0 .82 1,059 326.00 1.07 2,482 327 .00 2 .07 10,921 327 .30 2.37 14 ,057 Detention Pond Depth Vs. Volume 1.50 ...... -Cl> Cl> u.. -.s::. -a. Cl> a 1.00 0 2 ,000 4 ,000 6 ,000 8 ,000 l 0 ,000 12 ,000 14 ,000 16 ,000 Detention Pond Volume (Cubic Feet) 12 Rating Curve For Outlet Control Structure Weir Length(L): 0 .08 De th Vs. Volume Elevation Depth Discharge (Feet) Ft3/Sec 324.93 0 .00 0 .00 325 .00 0.07 0 .00 325 .75 0 .82 0.18 326.00 1.07 0 .28 327.00 2.07 0 .74 327.30 2.37 0 .91 Rating Curve For Outlet Control Structure Depth Vs. Volume 1.50 ...... -Cl> Cl> u.. ....., .t: -a. Cl> 0 1.00 0 .00 0 .20 0 .40 0 .60 0 .80 1.00 Discharge (Cubic Feet Per Second) 13 I Storage Indication Curve l.00 0 .90 0 .80 :g 0 .70 0 0 ~ a; 0 .60 Cl.. -(I) (I) LL. 0 0 .50 :0 ::J () -(I) 0 .40 O> 5 .s::. 0 £3 0.30 0 .20 0. 10 0 .00 Depth (Feet) 0 .00 0 .07 0 .82 1.07 2 .07 2.37 0.00 100 .00 Storage Discharge 2s/t 2s/t+O (Ft3) (Ft3/Sec) (Ft3/Sec) (Ft3/Sec) 0 0 .00 0 .00 0 .00 11 0 .00 0.37 0.37 1,059 0.18 35 .30 35 .48 2,482 0 .28 82 .73 83 .01 10,921 0 .74 364.03 364 .77 14 ,057 0.91 468 .57 469.48 Storage Indication Curve 200 .00 300 .00 400 .00 500.00 2s/t+O (Cubic Feet Per Second) 14 Inflow I Outflow Simulation 2-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (FVSec) 0 0.00 0.00 0.00 0.00 0.00 0.00 324.93 0.00 1 0.20 0.20 0.20 0.20 0.00 0.05 324.98 0.65 2 0.41 0.61 0.80 0.81 0.01 0.09 325.02 0.91 3 0.61 1.02 1.79 1.81 0.01 0.13 325.06 1.09 4 0.81 1.43 3.18 3.21 0.02 0.18 325.11 1.28 5 1.02 1.83 4.95 5.01 0.03 0.24 325.17 1.46 6 1.22 2.24 7.11 7.19 0.04 0.29 325.22 1.63 7 1.43 2.65 9.65 9.76 0.05 0.36 325.29 1.79 8 1.63 3.05 12.57 12.71 0.07 0.42 325.35 1.95 9 1.83 3.46 15.86 16.03 0.09 0.49 325.42 2.10 10 2.04 3.87 19.52 19.73 0.10 0.56 325.49 2.24 11 1.93 3.97 23.25 23.49 0.12 0.63 325.56 2.37 12 1.83 3.77 26.73 27.01 0.14 0.69 325.62 2.48 13 1.73 3.56 29.98 30.29 0.16 0.74 325.67 2.58 14 1.63 3.36 32.99 33.33 0.17 0.79 325.72 2.66 15 1.53 3.16 35.77 36.14 0.19 0.82 325.75 2.72 16 1.43 2.95 38.34 38.72 0.19 0.84 325.77 2.75 17 1.32 2.75 40.70 41.09 0.20 0.85 325.78 2.77 18 1.22 2.54 42.84 43.24 0.20 0.86 325.79 2.79 19 1.12 2.34 44.78 45.18 0.20 0.87 325.80 2.80 20 1.02 2.14 46.50 46.91 0.21 0.88 325.81 2.82 21 0.92 1.93 48.02 48.44 0.21 0.89 325.82 2.83 22 0.81 1.73 49.32 49.75 0.21 0.90 325.83 2.84 23 0.71 1.53 50.42 50.85 0.21 0.90 325.83 2.85 24 0.61 1.32 51.31 51.74 0.22 0.91 325.84 2.86 25 0.51 1.12 52.00 52.43 0.22 0.91 325.84 2.87 26 0.41 0.92 52.48 52.91 0.22 0.92 325.85 2.87 27 0.31 0.71 52.75 53.19 0.22 0.92 325.85 2.87 28 0.20 0.51 52.82 53.26 0.22 0.92 325.85 2.87 29 0.10 0.31 52.69 53.13 0.22 0.92 325.85 2.87 30 0.00 0.10 52.36 52.79 0.22 0.91 325.84 2.87 15 13' c 0 8 .00 7.00 6.00 g 5.00 <I) G> Q.. Q; Q) LL. 4.00 0 :0 :J u ....., ~ 3.00 :g 0 2.00 1.00 0.00 0 Inflow/Outflow Simulation 2-Year Storm Event l' I ' I ' I • I I • I I ., I I ' I . ' I I . I I ' ' ' '\. ' ' " . ' " ' . ' ' ' ' ' ; ,· / ""'' ' '\ .'/; "'"-', I 1/ • "" ' 5 10 15 20 25 Time (Minutes) 30 Pre -----Post-Post-- - ---• Post - Developme Developme Developme Developme nt nt Outflow nt Outflow nt "Free- Hydrograph Hydrograph With Flow· Without Detention Detention 16 Inflow I Outflow Simulation 5-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (FVSec) 0 0.00 0.00 0.00 0.00 0.00 0.00 324.93 0.00 1 0.25 0.25 0.24 0.25 0.00 0.05 324.98 0.69 2 0.50 0.74 0.97 0.98 0.01 0.10 325.03 0.94 3 0.74 1.24 2.18 2.21 0.01 0.15 325.08 1.15 4 0.99 1.73 3.87 3.91 0.02 0.20 325.13 1.35 5 1.24 2.23 6.03 6.09 0.03 0.27 325.20 1.54 6 1.49 2.72 8.65 8.75 0.05 0.33 325.26 1.73 7 1.73 3.22 11.74 11.87 0.06 0.40 325.33 1.90 8 1.98 3.71 15.29 15.46 0.08 0.48 325.41 2.07 9 2.23 4.21 19.30 19.50 0.10 0.55 325.48 2.23 10 2.48 4.70 23.75 24.00 0.13 0.63 325.56 2.39 11 2.35 4.83 28.28 28.58 0.15 0.71 325.64 2.53 12 2.23 4.58 32.51 32.86 0.17 0.78 325.71 2.65 13 2.10 4.33 36.47 36.85 0.19 0.83 325.76 2.73 14 1.98 4.08 40.17 40.56 0.19 0.85 325.78 2.76 15 1.86 3.84 43.60 44.00 0.20 0.87 325.80 2.79 16 1.73 3.59 46.78 47.19 0.21 0.88 325.81 2.82 17 1.61 3.34 49.69 50.12 0.21 0.90 325.83 2.85 18 1.49 3.09 52.35 52.79 0.22 0.91 325.84 2.87 19 1.36 2.85 54.75 55.20 0.22 0.93 325.86 2.89 20 1.24 2.60 56.90 57.35 0.23 0.94 325.87 2.91 21 1.11 2.35 58.79 59.25 0.23 0.95 325.88 2.92 22 0.99 2.10 60.43 60.89 0.23 0.96 325.89 2.94 23 0.87 1.86 61.81 62.28 0.24 0.96 325.89 2.95 24 0.74 1.61 62.94 63.42 0.24 0.97 325.90 2.96 25 0.62 1.36 63.83 64.31 0.24 0.98 325.91 2.96 26 0.50 1.11 64.46 64.94 0.24 0.98 325.91 2.97 27 0.37 0.87 64.84 65.32 0.24 0.98 325.91 2.97 28 0.25 0.62 64.98 65.46 0.24 0.98 325.91 2.97 29 0.12 0.37 64.86 65.35 0.24 0.98 325.91 2.97 30 0.00 0.12 64.50 64.99 0.24 0.98 325.91 2.97 17 15' c 0 0 Q) (/) .... Q) ICI.. '$ Q) u.. 0 :0 ::::> () ...., ~ 0 = ::::> 0 10.00 9.00 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00 Inflow/Outflow Simulation 5-Year Storm Event ~' • • • • • • • • I . • . . • . . • . . . . '" ' ~ ' ' ' ' ' ' ' ' ' ' ' . ' ' ' ' ' ' ' ' ' I " ·--, I ,' ""'', . . ' . ' ' ' ' ' ' ' •/' . : . : . : / • •• ! 0 5 10 15 20 Time (Minutes) Pre-----Post -Post - Developme De velopme Developme nt nt Outflow nt Outflow Hydrog raph Hydrograph With Without Det ent ion Detention 18 25 ---·---· 30 Post- Developme nt 'Free- Flow' Inflow I Outflow Simulation 10-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (Ft/Sec) 0 0.00 0.00 0.00 0.00 0.00 0.00 324.93 0.00 1 0.28 0.28 0.27 0.28 0.00 0.06 324.99 0.72 2 0.56 0.83 1.09 1.10 0.01 0.10 325.03 0.97 3 0.83 1.39 2.45 2.48 0.02 0.16 325.09 1.19 4 1.11 1.95 4.34 4.39 0.03 0.22 325.15 1.40 5 1.39 2.50 6.77 6.84 0.04 0.28 325.21 1.60 6 1.67 3.06 9.72 9.82 0.05 0.36 325.29 1.79 7 1.95 3.61 13.19 13.33 0.07 0.43 325.36 1.98 8 2.22 4.17 17.17 17.35 0.09 0.51 325.44 2.15 9 2.50 4.72 21.66 21.89 0.12 0.60 . 325.53 2.32 10 2.78 5.28 26.66 26.94 0.14 0.68 325.61 2.48 11 2.64 5.42 31.74 32.08 0.17 0.77 325.70 2.63 12 2.50 5.14 36.51 36.88 0.19 0.83 325.76 2.73 13 2.36 4.86 40.98 41.37 0.20 0.85 325.78 2.77 14 2.22 4.58 45.16 45.56 0.20 0.88 325.81 2.81 15 2.08 4.31 49.04 49.46 0.21 0.90 325.83 2.84 16 1.95 4.03 52.63 53.07 0.22 0.92 325.85 2.87 17 1.81 3.75 55.93 56.38 0.22 0.93 325.86 2.90 18 1.67 3.47 58.95 59.41 0.23 0.95 325.88 2.92 19 1.53 3.20 61.67 62.14 0.24 0.96 325.89 2.95 20 1.39 2.92 64.11 64.59 0.24 0.98 325.91 2.97 21 1.25 2.64 66.26 66.75 0.24 0.99 325.92 2.98 22 1.11 2.36 68.12 68.62 0.25 1.00 325.93 3.00 23 0.97 2.08 69.70 70.21 0.25 1.01 325.94 3.01 24 0.83 1.81 71.00 71.51 0.25 1.01 325.94 3.02 25 0.69 1.53 72.02 72.53 0.26 1.02 325.95 3.03 26 0.56 1.25 72.76 73.27 0.26 1.02 325.95 3.03 27 0.42 0.97 73.21 73.73 0.26 1.02 325.95 3.04 28 0.28 0.69 73.39 73.91 0.26 1.02 325.95 3.04 29 0.14 0.42 73.29 73.81 0.26 1.02 325.95 3.04 30 0.00 0.14 72.92 73.43 0.26 1.02 325.95 3.03 19 Inflow/Outflow Simulation 10-Year Storm Event 12.00 ' I ' 10 .00 ' ' ' I ' I ' I ' I ' ,... "O I ' c: 8.00 0 I 0 ' Q) • ' <I) I ' ' ' ... Q) 0.. -Q) Q) 6.00 ...... 0 :0 :J () ........ ~ 0 = 4.00 :J 0 2.00 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post -··--·--· Post- Developm e Developme Develo p me Develo pm e nt nt Outflow nt O utfl ow nt 'Free- Hydrograph Hydrograph Wit h Flow· Without Detenti on Detention 20 Inflow I Outflow Simulation 25-Year Storm Event Time Inflow 11+ 12 2s/t-O 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (FVSec) 0 0.00 0.00 0.00 0.00 0.00 0.00 324.93 0.00 1 0.32 0.32 0.31 0.32 0.00 0.06 324.99 0.75 2 0.63 0.95 1.24 1.26 0.01 0.11 325.04 1.00 3 0.95 1.59 2.80 2.83 0.02 0.17 325.10 1.23 4 1.27 2.22 4.96 5.02 0.03 0.24 325.17 1.46 5 1.59 2.86 7.73 7.82 0.04 0.31 325.24 1.67 6 1.90 3.49 11.10 11.22 0.06 0.39 325.32 1.87 7 2.22 4.13 15.06 15.23 0.08 0.47 325.40 2.06 8 2.54 4.76 19.62 19.82 0.10 0.56 325.49 2.25 9 2.86 5.39 24.75 25.01 0.13 0.65 325.58 2.42 10 3.17 6.03 30.46 30.78 0.16 0.75 325.68 2.59 11 3.01 6.19 36.27 36.64 0.19 0.83 325.76 2.73 12 2.86 5.87 41.75 42.14 0.20 0.86 325.79 2.78 13 2.70 5.55 46.88 47.30 0.21 0.89 325.82 2.82 14 2.54 5.24 51.69 52.12 0.22 0.91 325.84 2.86 15 2.38 4.92 56.16 56.61 0.23 0.94 325.87 2.90 16 2.22 4.60 60.29 60.76 0.23 0.96 325.89 2.93 17 2.06 4.28 64.09 64.57 0.24 0.98 325.91 2.97 18 1.90 3.97 67.57 68.06 0.25 0.99 325.92 2.99 19 1.75 3.65 70.71 71.22 0.25 1.01 325.94 3.02 20 1.59 3.33 73.52 74.04 0.26 1.03 325.96 3.04 21 1.43 3.01 76.01 76.54 0.26 1.04 325.97 3.06 22 1.27 2.70 78.18 78.71 0.27 1.05 325.98 3.07 23 1.11 2.38 80.01 80.56 0.27 1.06 325.99 3.09 24 0.95 2.06 81.53 82.08 0.27 1.07 326.00 3.10 25 0.79 1.75 82.72 83.27 0.28 1.07 326.00 3.10 26 0.63 1.43 83.60 84.15 0.28 1.07 326.00 3.11 27 0.48 1.11 84.15 84.71 0.28 1.08 326.01 3.11 28 0.32 0.79 84.39 84.94 0.28 1.08 326.01 3.12 29 0.16 0.48 84.30 84.86 0.28 1.08 326.01 3.11 30 0.00 0.16 83.91 84.46 0.28 1.08 326.01 3.11 21 15' c 0 0 Q) Cl) 14 .00 12 .00 10 .00 £ 8.00 Q; Q) LL. 0 :.0 8 6 .00 ~ ~ 0 =§ 0 4 .00 2.00 0 .00 Inflow/Outflow Simulation 25-Year Storm Event . I I I I . ·~1· I ,' I ,' I • • I • . . /..i .~/ I/ 0 5 Pre-- Developme nt Hydrog raph --- I ~ . ' I ' I ' I ' I ' ' .. ' ' )to. ' . ' ' . ' . ' ' . ' . ' ' ' 10 15 20 25 Time (Minutes) Post-Post -..... -............... Developme Developme nt Outflow nt O utflow Hydrograph With Without Det ention Detention 22 30 Post- Developme nt "Free- Flow · Inflow I Outflow Simulation 50-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (FVSec) 0 0.00 0.00 0.00 0.00 0.00 0.00 324.93 0.00 1 0.36 0.36 0.35 0.36 0.00 0.07 325.00 0.78 2 0.72 1.08 1.41 1.43 0.01 0.12 325.05 1.03 3 1.08 1.79 3.16 3.20 0.02 0.18 325.11 1.28 4 1.43 2.51 5.61 5.67 0.03 0.25 325.18 1.51 5 1.79 3.23 8.74 8.84 0.05 0.33 325.26 1.73 6 2.15 3.95 12.55 12.69 0.07 0.42 325.35 1.94 7 2.51 4.66 17.03 17.22 0.09 0.51 325.44 2.15 8 2.87 5.38 22.18 22.41 0.12 0.61 325.54 2.34 9 3.23 6.10 27.98 28.28 0.15 0.71 325.64 2.52 10 3.59 6.82 34.43 34.80 0.18 0.81 325.74 2.70 11 3.41 7.00 41.04 41.43 0.20 0.85 325.78 2.77 12 3.23 6.64 47.26 47.67 0.21 0.89 325.82 2.83 13 3.05 6.28 53.10 53.53 0.22 0.92 325.85 2.88 14 2.87 5.92 58.56 59.02 0.23 0.95 325.88 2.92 15 2.69 5.56 63.64 64.12 0.24 0.97 325.90 2.96 16 2.51 5.20 68.34 68.84 0.25 1.00 325.93 3.00 17 2.33 4.84 72.67 73.18 0.26 1.02 325.95 3.03 18 2.15 4.48 76.63 77.15 0.26 1.04 325.97 3.06 19 1.97 4.13 80.21 80.75 0.27 1.06 325.99 3.09 20 1.79 3.77 83.42 83.98 0.28 1.07 326.00 3.11 21 1.61 3.41 86.27 86.83 0.28 1.09 326.02 3.13 22 1.43 3.05 88.74 89.31 0.29 1.10 326.03 3.14 23 1.26 2.69 90.85 91.43 0.29 1.11 326.04 3.15 24 1.08 2.33 92.60 93.19 0.29 1.11 326.04 3.17 25 0.90 1.97 93.98 94.57 0.29 1.12 326.05 3.17 26 0.72 1.61 95.01 95.60 0.30 1.12 326.05 3.18 27 0.54 1.26 95.67 96.26 0.30 1.13 326.06 3.18 28 0.36 0.90 95.97 96.56 0.30 1.13 326.06 3.19 29 0.18 0.54 95.91 96.51 0.30 1.13 326.06 3.18 30 0.00 0.18 95.49 96.09 0.30 1.13 326.06 3.18 23 Inflow/Outflow Simulation 50-Year Storm Event 14 .00 I ' I " I ' • 12 .00 I ' I ' • ' • ' ' I ' I 10.00 ...... "O c 0 0 Cl> Cl) .... Cl> 8 .00 Q.. -Cl> Cl> ..... 0 :.0 j 6 .00 () -~ 0 = j 0 4 .00 2 .00 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post -............... Post- Developm e Developme Developme Developme nt nt Outflow nt Outflow nt "Free- Hydrog raph Hydr ograph With Fl ow" Without Det ention Detention 24 Inflow I Outflow Simulation 100-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation Velocity (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) (Ft/Sec) 0 0.00 0.00 0.00 0.00 0.00 0.00 324.93 0.00 1 0.37 0.37 0.37 0.37 0.00 0.07 325.00 0.79 2 0.75 1.12 1.47 1.49 0.01 0.12 325.05 1.04 3 1.12 1.87 3.30 3.34 0.02 0.19 325.12 1.29 4 1.50 2.62 5.86 5.92 0.03 0.26 325.19 1.53 5 1.87 3.37 9.13 9.23 0.05 0.34 325.27 1.76 6 2.25 4.12 13.11 13.25 0.07 0.43 325.36 1.97 7 2.62 4.87 17.79 17.98 0.09 0.53 325.46 2.18 8 3.00 5.62 23.16 23.40 0.12 0.62 325.55 2.37 9 3.37 6.37 29.22 29.53 0.15 0.73 325.66 2.56 10 3.75 7.12 35.96 36.33 0.19 0.82 325.75 2.72 11 3.56 7.30 42.86 43.26 0.20 0.86 325.79 2.79 12 3.37 6.93 49.37 49.79 0.21 0.90 325.83 2.84 13 3.18 6.55 55.48 55.92 0.22 0.93 325.86 2.90 14 3.00 6.18 61.19 61.66 0.23 0.96 325.89 2.94 15 2.81 5.81 66.50 66.99 0.25 0.99 325.92 2.98 16 2.62 5.43 71.42 71.93 0.25 1.01 325.94 3.02 17 2.43 5.06 75.95 76.48 0.26 1.04 325.97 3.06 18 2.25 4.68 80.09 80.64 0.27 1.06 325.99 3.09 19 2.06 4.31 83.85 84.40 0.28 1.08 326.01 3.11 20 1.87 3.93 87.21 87.78 0.28 1.09 326.02 3.13 21 1.69 3.56 90.19 90.77 0.29 1.10 326.03 3.15 22 1.50 3.18 92.79 93.38 0.29 1.11 326.04 3.17 23 1.31 2.81 95.01 95.60 0.30 1.12 326.05 3.18 24 1.12 2.43 96.84 97.44 0.30 1.13 326.06 3.19 25 0.94 2.06 98.30 98.90 0.30 1.14 326.07 3.20 26 0.75 1.69 99.38 99.98 0.30 1.14 326.07 3.21 27 0.56 1.31 100.08 100,69 0.30 1.14 326.07 3.21 28 0.37 0.94 100.40 101.01 0.31 1.15 326.08 3.21 29 0.19 0.56 100.35 100.97 0.31 1.15 326.08 3.21 30 0.00 0.19 99.93 100.54 0.30 1.14 326.07 3.21 25 ....... 'O c 0 16.00 14.00 12 .00 ~ 10 .00 (/) Qi a.. Qi Q) LL. 0 :0 ::J u ...... ~ 0 = ::J 0 8.00 6.00 4.00 2.00 0.00 Inflow/Outflow Simulation 100-Year Storm Event I I I I . ..... / I '/' I ,' :.:! I 0 5 Pre ---- Developme nt Hydrograph I I I I I I • I ' I ' ' ' . ' . . ' ' .. ... ' ' ' ,/j~·---.. , 10 15 ' ' ' 20 Time (Minutes) -Post-Post- Developme Developme nt Outflow nt O utflow Hydrograph Wit h Without Detention Detention 26 25 30 ......... Post- Developme nt "Free- Flow· Inflow/Outflow Simulation 2-Year Storm Event 0 5 10 15 20 25 30 Time (Minutes) Pre-Dev elopment Hydrograph ----To t a l Post-Development Hydrograph 27 Inflow/Outflow Simulation 5-Year Storm Event 6 .00 ....... "O c 0 5.00 0 Cl> (/) ... Cl> a.. -Cl> Cl> 4 .00 I.I- 0 :0 :J () .._, ~ 0 3.00 :;: :J 0 2 .00 0 5 10 15 20 25 30 Time (Minutes) Pre -Development Hydrograph ----Tota l Post-Developm ent Hydrograph 28 Inflow/Outflow Simulation 10-Year Storm Event 9 .00 8 .00 7.00 2 .00 1.00 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre-Development Hydrograph ----Tota l Post-Development Hydrograph 29 Inflow/Outflow Simulation 25-Year Storm Event 10 .00 9 .00 8 .00 7 .00 ....... 'O c: 0 0 Q) 6 .00 Cl) ... Q) Q... -Q) Q) 5 .00 ~ 0 :.0 :::J u ......, ~ 4.00 0 E :::J 0 3 .00 2 .00 1.00 0 .00 0 5 10 15 20 25 30 Time (Minutes) ---Pre-Development Hydrograph ----To t al Post-Development Hydrograph 30 Inflow/Outflow Simulation 50-Year Storm Event ...... 8.00 "O c: 0 0 Cl> (/) .... Cl> 0.. -Cl> Cl> 6.00 u.. 0 :0 ::::J () -~ 0 s: ::::J 0 4.00 0 5 10 15 20 25 30 Time (Minutes) Pre-Development Hydrograph ----Total Post-De velopment Hydrograph 31 Inflow/Outflow Simulation 100-Year Storm Event 12.00 10 .00 ,,...,, 8.00 "O c: 0 0 G> Cl) ... G> a.. -G> G> 6 .00 u.. 0 :a :J (.) -~ 0 = :J 0 4 .00 2.00 0 .00 0 5 10 15 20 25 30 Time (Minutes) ----Pre-Development Hydrograph ----Tota l Post-Development Hydrograph 32 Detention Pond Stora ge Volumes as Pe rcent o f M aximum Volu m e 100% 90% 80% 70% CD E ::::J 0 60% > E ::::J E ")( 50% 0 :E 0 -40% c CD 0 .... CD Q.. 30% 20% 10% 0% 2-year 5-year 10-year 25-year 50-year 100-year Design Stor m Sto rm Simulation Synopsis 2-ear 5-ear 10-ear 25-ear 100-ear Storm Depth 0.92 0.98 1.02 1.08 1.15 Storm Elevation 325.85 325.91 325.95 326 .01 326 .06 326 .08 Storm Volume 1614 1978 2223 2552 2965 3121 Maximum Capacity 14057 14057 14057 14057 14057 14057 Percent of Capacity 11% 14% 16% 18% 21% 22% 33 DRAINAGE COMPUTATIONS for Summit Street Four-Plexes being Lots 1R-4R Of A Replat Of Block 14A Southwood Valley -Section 19 College Station, Brazos County, Texas Prepared for Mr. Tony Jones 4475 Hicks Lane College Station, Texas 77845 Prepared by.· Garrett Engineering 4444 Carter Creek Parkway -Suite 108 Bryan, Texas 77802 Telephone: {409) 846-2688 *April, 1995 * DRAINAGE COMPUTATIONS for Summit Street Four-Plexes being Lots 1R-4R Of A Replat Of Block 14A Southwood Valley -Section 19 College Station, Brazos County , Texas Prepared for Mr. Tony Jones 4475 Hicks Lane College Station, Texas 77845 Prepared by: Garrett Engineering 4444 Carter Creek Parkway -Suite 108 Bryan, Texas 77802 Telephone: (409) 846-2688 *April, 1995 * DRAINAGE COMPUTATIONS for A Replat of Block 14A Southwood Valley -Section 19 College Station, Brazos County, Texas * April, 1995 * SUMMARY The project is situated off F.M. 2818 between Southwood and Hilltop drives in the Southwood Valley Subdivision, College Station, Brazos County, Texas. Block 14A of Southwood Valley - Section 19 consists of 4 lots being established within the bounds of the 1.94 acre tract. The total drainage area tributary to the project is 1.94 acres. The pre-development run-off coefficient was estimated to be 0.40, while taking into account typical residential site improvements would result in a post-development run-off coefficient of 0.63. Detention facilities will be constructed at different locations on the property to ensure the collection of necessary runoff volumes and make use of practical drainage patterns. 111fee detention ponds are designed wit11 capacity to facilitate up to and including the 100-year storm event and discharge at a rate less than the current pre-development peak discharge rate. The detention ponds will intercept, store and meter run-off from 1.20 acres of the total project surface area. TI1e run-off generated on the remaining 0.74 acres will "free-flow" across the site unmetered. These report calculations are summarized according to the following methodology. The report is divided into 3 sections corresponding to Ponds A tl1fough C. Beginning on page 1 of each section, tl1e relative pre-development peak discharge rate ("Q") was determined based on the total tributary drainage area of the project (being 1.94 acres for tl1e whole tract, but reflecting the specific drainage area for pond of tlrnt section), tl1e pre-development run-off coefficient (assumed at 0.40), and a minimum time of concentration of 10 minutes, . TI1e Rational Method was utilized to arrive at the estimated peak pre-development discharge rates. TI1e equation that represents the Rational Metl1od is as follows: Q = CIA. "Q" is the peak discharge rate in cubic feet per second, "C" is the run-off coefficient, assumed to be 0.40 in tl1e pre-development condition, "I" is tl1e storm intensity in inches per hour, and "A" is the area of the drainage basin in acres. Similarly the computations on page 2 are based on the relative tributary area, tl1e post- development run-off coefficient of 0.63 (being weighted according to the relative amounts of pervious and impervious surface area), and the same minimum time of concentration of 10 minutes, to yield tl1e corresponding post-development peak discharge rate ("Q"). The Rational Method was again used: Q = CIA, where; "Q" is the peak discharge rate in cubic feet per second. TI1e "C" variable is tl1e run-off coefficient. (In the post-development condition "C" is assumed to be 0.63.) "I" represents the rainfall intensity in inches per hour, and similarly "A" is the area of the basin in acres. · Comparison of the peak pre-development discharge rate to the post-development discharge rate is included in the report to aid the designer in establishing a preliminary "target" of detention volume required. 111is preliminary estimate is determined as the volume difference generated between the pre-development and post-development hydrographs. (See pages 9-11 of each section for pre-development and post-development hydrographs.) Please note that the post- development hydrograph shown on these same graphs assumes no detention and reflects the "worst-case" scenario that all run-off is allowed to free-flow. Pages 3 and 4 provide information concerning the post-development run-off that is not routed through the detention facility ("free-flow") as well as the post-development run-off that is routed through the detention facility and retained on site. Page 5 and page 6 are tabulations of the pre-development and the post-development hydrographs based on the computations performed on page l and page 2. 1l1e post-development hydrograph assumes no detention to facilitate direct comparison in the pre-and post-development conditions. Page 7 and page 8 are tabulations of the post-development hydrograph for run-off directed through the detention facility and the post-development hydrograph for "free-flow" from the project site. From the computations on page 4, the actual peak post-development "inflow" rate supplied to the proposed detention facility was determined. With this "inflow" rate and the time of concentration (10 minutes), the hydrograph is derived and shown on page 8. The hydrograph is simplified as being triangular in shape and is based on the standard SCS unit hydrograph with time to peak set equal to the time of concentration and the total time base set at 3.00 times the time of concentration. Please note that a 30 minute total storm event duration was utilized exclusively throughout this report due to the relative small size of the project. Having derived the preliminary volume requirements and "allowable peak" discharge rate, it is now possible to design the final detention facility and outlet control structure. Page 12 presents a data tabulation and a depth versus volume graph of the detention facility. The maximum depth of the pond was set according to the required capacity and the specified freeboard requirements outlined in city ordinances. Page 13 supplies a tabulation and a ratfog curve for the proposed outlet control structure. A metering pipe was chosen for t11e outlet control structure due to depth verses discharge ratio characteristics associated with the anticipated shallow headwater depth. An ultimate storage depth of 1.5 feet is available due to the physical geometry of the pond. However, even .at 100- year storm conditions, depths of less than 1.0 feet are anticipated . Page 14 presents a tabulation of the relationship between discharge from the detention facility and t11e dimensionless quantity 2S/t+O. Also presented is a Storage Indication Curve for the detention facility based on t11e aforementioned physical characteristics of the detention pond, storage volume, inflow hydrograph, and rating curve for the outlet structure. 111e storage indication curve as shown on page 12 is a graphical solution to the equation presented in the "Drainage Policy And Design Standards" as follows: 2s1 (I 1 + I 2) + (----------------01) dt 2s2 = (-----------------+ 02) dt Page 15 through page 26 present simulations of the 2, 5, 10, 25, 50, and 100 year storm events. 111e first page of each storm simulation represents the tabulated data for the storm event. The maximum dept11 achieved in the detention pond during each simulation is shown below as is the time at during which this maximum dept11 occurs from the onset of the storm event. The calculated peak discharge rate corresponding to this depth over same period is also shown. Additionally, the maximum water surface elevation achieved during each event and the maximum peak discharge during each event can be found in the table. 111e second page of each storm simulation presents a graph of the pre-development hydrograph, the post-development hydrograph (with no detention), the post-development hydrograph as routed through the detention pond, and post-development "free-flow" hydrograph for each storm event. Page 27 through page 32 provide total inflow/outflow hydrographs for the 2, 5, 10, 25, 50 and 100-year pre-development and post-development storm events. 111ese hydrographs show that the post-development peak discharge rates have been slightly decreased from the peak pre- development discharge rates due to the incorporation of the detention facilities. Total post-development peak discharge rates from t11e outlet control structure and the project site as a whole are kept less than t11e pre-development peak discharge rates. Subsequent peak post- development discharge velocitiesare projected to be within reasonable limits. DRAINAGE COMPUTATIONS for Detention Pond 11 A 11 -Summit Street Four-Plexes being Lots 1R-4R Of A Replat Of Block 14A Southwood Valley -Section 19 College Station, Brazos County, Texas Prepared for Mr. Tony Jones 4475 Hicks Lane College Station, Texas 77845 Prepared by: Garrett Engineering 4444 Carter Creek Parkway -Suite 108 Bryan, Texas 77802 Telephone: (409) 846-2688 * April, 1995 * Determine Total Pre-Development Peak Storm Water· Dischar e Rates Tributary Area ("A"): 0.53 Acres Pervious Area : 0 .52 Acres Impervious Area: 0 .01 Acres Run-Off Coefficient ("Cwt"): 0.41 Time Of Concentration ("T/c"): Woodlands: Low Elevation : High Elevation : Distance (Feet): Slope (%Grade): Velocity ("Vw"): Time : Pastures: Low Elevation : High Elevation : Distance (Feet): Slope (%Grade): Velocity ("Vp "): Time : Pavements: Low Elevation : High Elevation : Distance (Feet): Slope (%Grade): Velocity ("Vpave"): Time : Total Travel Time: Hourly Intensity Rates ("I "): 2-Year: 6 .33 5-Year: 7 .69 10-Year: 8.63 25-Year: 9.86 50-Year: 11 .15 100-Year: 11 .64 Peak D ischarge Rate ("Q "): 2-Year: 1.38 5-Year: 1.68 10-Year: 1.88 25-Year: 2 .15 50-Year: 2.43 100-Year: 2 .54 C= 0.40 C= 0 .98 0 .00 0 .00 0.00 0.00 0.00 Feet I Second 0 .00 Minutes 0.00 0.00 0.00 0 .00 0 .00 Feet I Second 0 .00 Minutes 0 .00 0 .00 0 .00 0 .00 0.00 Feet I Second 0 .00 Minutes 10.00 Minutes Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Determine Post~d~velopment Peak Storm Water Dischar e No Detention Tr ibutary Area ("A"): 0.53 Acres Pervious Area : 0.30 Acres Impervious Area : 0.23 Acres Run-Off Coefficient ("Cwt"): 0.65 Time Of Concentration ("T/c"): 1 O Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 6.33 5-Year: 7.69 10-Year: 8.63 25-Year: 9.86 50-Year: 11.15 100-Year: 11.64 c = 0.40 C= 0.98 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Peak Discharge Rate ("Q"): 2-Year: 2.19 Cubic Feet I Second 5-Year: 2.66 Cubic Feet I Second 10-Year: 2.98 Cubic Feet I Second 25-Year: 3.41 Cubic Feet I Second 50-Year: 3 .85 Cubic Feet I Second 100-Year: 4 .02 Cubic Feet I Second Comparison Of Predevelopment And Post-develo ment Peak Dischar e Rates . ' Predevelopment Post -Development Increase 2-Year: 1 .38 Ft3/sec 2.19 Ft3/sec 0.81 Ft3/sec 5-Year: 1.68 Ft3/sec 2.66 Ft3/sec 0.98 Ft3/sec 10-Year: 1.88 Ft3/sec 2.98 Ft3 /sec 1 .1 O Ft3/sec 25-Year: 2.15 Ft3/sec 3.41 Ft3/sec 1 .26 Ft3/sec 50-Year: 2.43 Ft3/sec 3.85 Ft3/sec 1 .42 Ft3/sec 100-Year: 2.54 Ft3/sec 4 .02 Ft3 /sec 1 .49 Ft3/sec Preliminary Determinati9n Of Detention Pond Volume _,~ ~-....,.,-1 2-Year: 0.81 Ft3/sec x (30 Mi n. x 60 Sec . I 2 ) = 727 Cub ic 5-Year: 0.98 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 883 Cubic 10-Year: 1.1 O Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 992 Cubic 25-Year: 1 .26 Ft3/se c x (30 Min . x 60 Sec . I 2 ) = 1,132 Cubic 50-Year: 1 .42 Ft3 /sec x (30 Min . x 60 Sec . I 2 ) = 1,280 Cubic 100-Year: 1 .49 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 1,337 Cubic 2 Feet Feet Feet Feet Feet Feet Determine Post-Development 11 Free-Flow 11 Peak Storm Water Discharge Tributary Area ("A"): 0.18 Acres Pervious Area : 0.04 Acres Impervious Area : 0.14 Acres Run-Off Coefficient ("Cwt "): 0.85 Time Of Concentration ("T/c"): 10 Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 6.33 5-Year: 7.69 10-Year: 8.63 25-Year: 9.86 50-Year: 11.15 100-Year: 11 .64 Peak Discharge Rate ("O"): 2-Year: 0.97 5-Year: 1.18 10-Year: 1.32 25-Year: 1.51 50-Year: 1.71 100-Year: 1.78 3 c = 0.40 C = 0.98 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second . Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Determine Post-Development Flow Into Detention Pond Tributary Area ("A"): 0.35 Acres Pervious Area : 0.26 Acres Impervious Area : 0.09 Acres Run -Off Coefficient ("Cwt"): 0.55 Time Of Concentration ("T/c "): 10 Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 6.33 5-Year : 7.69 10-Year: 8.63 25-Year: 9.86 50-Year: 11 .15 100-Year: 11.64 Peak Discharge Rate ("Q"): 2-Year: 1.22 5-Year: 1.48 10-Year: 1.66 25-Year: 1.90 50-Year: 2.14 100-Year: 2.24 4 c = 0.40 C= 0.98 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Pre-Deve lopment Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year {M inutes} Storm Storm Storm Storm Storm Storm 0 0 .00 0 .00 0.00 0.00 0.00 0 .00 0.14 0 .17 0.19 0.21 0.24 0 .25 2 0 .28 0 .34 0 .38 0.43 0.49 0.51 3 0.41 0 .50 0 .56 0 .64 0.73 0.76 4 0 .55 0 .67 0.75 0.86 0 .97 1.01 5 0.69 0 .84 0.94 1.07 1.21 1.27 6 0 .83 1.01 1.13 1.29 1.46 1.52 7 0 .96 1.17 1.32 1.50 1.70 1.77 8 1.10 1.34 1.50 1.72 1.94 2.03 9 1.24 1.51 1.93 2.19 2.28 Peak=> 10 1.38 1.68 2.15 2.43 2.54 11 1.31 1.59 1.79 2.04 2.31 2.41 12 1.24 1.51 1.69 1.93 2.19 2.28 13 1.17 1.42 1.60 1.83 2.06 2 .15 14 1.10 1.34 1.50 1.72 1.94 2 .03 15 1.03 1.26 1.41 1.61 1.82 1.90 16 0 .96 1.17 1.32 1.50 1.70 1.77 17 0.90 1.09 1.22 1.40 1.58 1.65 18 0 .83 1.01 1.13 1.29 1.46 1.52 19 0.76 0.92 1.03 1.18 1.34 1.39 20 0 .69 0 .84 0 .94 1.07 1.21 1.27 21 0 .62 0.75 0 .85 0.97 1.09 1.14 22 0 .55 0 .67 0 .75 0 .86 0.97 1.01 23 0.48 0 .59 0 .66 0.75 0 .85 0 .89 24 0.41 0 .50 0 .56 0.64 0 .73 0 .76 25 0 .34 0.42 0.47 0.54 0 .61 0 .63 26 0 .28 0 .34 0.38 0.43 0.49 0 .51 27 0 .21 0 .25 0 .28 0 .32 0.36 0 .38 28 0 .14 0 .17 0.19 0 .21 0 .24 0 .25 29 0 .07 0 .08 0.09 0 .11 0 .12 0.13 30 0 .00 0 .00 0.00 0.00 0 .00 0.00 5 Post-Development Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.22 0.27 0.30 0.34 0.39 0.40 2 0.44 0.53 0.60 0.68 0.77 0.80 3 0.66 0.80 0.89 1.02 1.16 1.21 4 0.87 1.06 1.19 1.36 1.54 1.61 5 1.09 1.33 1.49 1.70 1.93 2.01 6 1.31 1.59 1.79 2.04 2.31 2.41 7 1.53 1.86 2.09 2.38 2.70 2.81 8 1.75 2.13 2.39 2.72 3.08 3.22 9 1.97 2.39 2.68 3.07 3.47 3.62 Peak=> r 10 I' .. 2.19 "2_&§, 12.98 .. 3.41 3.85;:..,. .4.02. 11 2.08 2.52 2.83 3.24 3.66 3.82 12 1.97 2.39 2.68 3.07 3.47 3.62 13 1.86 2.26 2.54 2.90 3.27 3.42 14 1.75 2.13 2.39 2.72 3.08 3.22 15 1.64 1.99 2.24 2.55 2.89 3.02 16 1.53 1.86 2.09 2.38 2.70 2.81 17 1.42 1.73 1.94 2.21 2.50 2.61 18 1.31 1.59 1.79 2.04 2.31 2.41 19 1.20 1.46 1.64 1.87 2.12 2.21 20 1.09 1.33 1.49 1.70 1.93 2.01 21 0.98 1.20 1.34 1.53 1.73 1.81 22 0.87 1.06 1.19 1.36 1.54 1.61 23 0.76 0.93 1.04 1.19 1.35 1.41 24 0.66 0.80 0.89 1.02 1.16 1.21 25 0.55 0.66 0.75 0.85 0.96 1.01 26 0.44 0.53 0.60 0.68 0.77 0.80 27 0.33 0.40 0.45 0.51 0.58 0.60 28 0.22 0.27 0.30 0.34 0.39 0.40 29 0.11 0.13 0.15 0.17 0.19 0.20 30 0.00 0.00 0.00 0.00 0.00 0.00 6 Post-Development "Free-Flow" Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.10 0.12 0.13 0.15 0.17 0.18 2 0.19 0.24 0.26 0.30 0.34 0.36 3 0.29 0.35 0.40 0.45 0.51 0.53 4 0.39 0.47 0.53 0.60 0.68 0.71 5 0.48 0.59 0.66 0.76 0.85 0.89 6 0.58 0.71 0.79 0.91 1.02 1.07 7 0.68 0.82 0.93 1.06 1.20 1.25 8 0.78 0.94 1.06 1.21 1.37 1.43 9 0.87 1.06 1.19 1.36 1.54 1.60 Peak=> L! 10 0.97 118-_ ,.' ;1:32, ! t51 ,, 1.71 :.... 1,78 11 0.92 1.12 1.26 1.44 1.62 1.69 12 0.87 1.06 1.19 1.36 1.54 1.60 13 0.82 1.00 1.12 1.28 1.45 1.52. 14 0.78 0.94 1.06 1.21 1.37 1.43 15 0.73 0.88 0.99 1.13 1.28 1.34 16 0.68 0.82 0.93 1.06 1.20 1.25 17 0.63 0.77 0.86 0.98 1.11 1.16 18 0.58 0.71 0.79 0.91 1.02 1.07 19 0.53 0.65 0.73 0.83 0.94 0.98 20 0.48 0.59 0.66 0.76 0.85 0.89 21 0.44 0.53 0.60 0.68 0.77 0.80 22 0.39 0.47 0.53 0.60 0.68 0.71 23 0.34 0.41 0.46 0.53 0.60 0.62 24 0.29 0.35 0.40 0.45 0.51 0.53 25 0.24 0.29 0.33 0.38 0.43 0.45 26 0.19 0.24 0.26 0.30 0.34 0.36 27 0.15 0.18 0.20 0.23 0.26 0.27 28 0.10 0.12 0.13 0.15 0.17 0.18 29 0.05 0.06 0.07 0.08 0.09 0.09 30 0.00 0.00 0.00 0.00 0.00 0.00 7 Post-Development Flow Routed Through Detention Pond Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 0.12 0.15 0.17 0.19 0.21 0.22 2 0.24 0.30 0.33 0.38 0.43 0.45 3 0.36 0.44 0.50 0.57 0.64 0.67 4 0.49 0.59 0.66 0.76 0.86 0.89 5 0.61 0.74 0.83 0.95 1.07 1.12 6 0.73 0.89 1.00 1.14 1.29 1.34 7 0.85 1.03 1.16 1.33 1.50 1.57 0.97 1.18 1.33 1.52 1.71 1.79 1.09 1.33 1.49 1.71 1.93 2.01 Peak=> I -~ - -.-.-..,.... -~-,-., 10~ ' 1.48 .t§.6 _.. 1.90 ' 2.14·. 2:2_1 11 1.16 1.40 1.58 1.80 2.04 2.13 12 1.09 1.33 1.49 1.71 1.93 2.01 13 1.03 1.26 1.41 1.61 1.82 1.90 14 0.97 1.18 1.33 1.52 1.71 1.79 15 0.91 1.11 1.24 1.42 1.61 1.68 16 0.85 1.03 1.16 1.33 1.50 1.57 17 0.79 0.96 1.08 1.23 1.39 1.45 18 0.73 0.89 1.00 1.14 1.29 1.34 19 0.67 0.81 0.91 1.04 1.18 1.23 20 0.61 0.74 0.83 0.95 1.07 1.12 21 0.55 0.67 0.75 0.85 0.96 1.01 22 0.49 0.59 0.66 0.76 0.86 0.89 23 0.43 0.52 0.58 0.66 0.75 0.78 24 0.36 0.44 0.50 0.57 0.64 0.67 25 0.30 0.37 0.41 0.47 0.54 0.56 26 0.24 0.30 0.33 0.38 0.43 0.45 27 0.18 0.22 0.25 0.28 0.32 0.34 28 0.12 0.15 0.17 0.19 0.21 0.22 29 0.06 0.07 0.08 0.09 0.11 0.11 30 0.00 0.00 0.00 0.00 0.00 0.00 8 ... Q) Q,,, -Q) Q) LL. 0 ....... ·-"O .0 c :J 0 u 0 ....... Q) Q) (/) O> ... 0 .s::. 0 .,, a 2.50 2.00 l .50 l.00 0.50 0.00 0 Total Pre-Development Vs. Total Post -Developm~nt (No Detention) Peak Discharge Rates 2-Year Storm Event 5 10 15 20 25 Time (Minutes) Pre-Development Hydrograph Total Post-Development Hydrograph Total Pre-Development Vs. Total Post-Development (No · Detention) Peak Discharge Rates 5-Year Storm Event 30 0 .00 ~---+----+----..,_-----t~-----j~-__;=:i..e 0 5 10 15 20 25 Time (Minutes) Pre-Development Hydrograph 9 Post-Development Outflow Hydrograph Without Detention 30 3 .00 -Q) 2.50 a.. -Q) Q) 2.00 u.. 0 ...... ·-"O .0 c: :J 0 1.50 u 0 ..._, Q) Q) (/) O'> 1.00 -0 .l: 0 0 .50 I/) i5 0.00 0 Total Pre-Development Vs. Total Post-Development (No · Detention) Peak Discharge Rates 10-Year Storm Event 5 10 15 20 25 Time (Minutes) 30 Pre -Development Hydrograph ----Post-D evelopment Outflow Hydrograph Without Detention 3.50 -3.00 Q) a.. -Q) 2 .50 Q) u.. 0 ...... ·-"O 2 .00 .0 c: :J 0 u 0 1.50 ..._, Q) Q) (/) O'> -1.00 0 .l: 0 I/) 0.50 i5 0.00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 25-Year Storm Event 5 10 15 20 25 Time (Minutes) 30 Pre-Development Hydrograph Post-Development Outflo w Hydrograph Without Detenti on ' 4 .00 ... 3.50 Q) Cl.. -3.00 Q) Q) u.. 0 ........ 2.50 ·-"O .0 c: 8 8 2.00 ....... Q) Q) Cl) 1.50 Ol ... 0 1.00 ~ 0 V) a 0.50 0 .00 0 Total Pre-Development Vs . Total Post -Development (No Detention) Peak Discharge Rates 50-Year Storm · Event 5 10 15 20 25 Time (Minutes) 30 Pre-Develop111ent Hydrog raph ---Post -Dev elopment Outflow Hydrograph Without Detention Total Pre-Development Vs. Total Post-Development (No . Detention) Peak Discharge Rates 100-Year Storm Event ... £ 4 .oo ...-----t-----.i!'oo::-----+----i------+----~ Q) 3.50 ...-----t---_,_-+--~~-+----t------+----~ Q) ~ ........ 3.00 ...-----t---+---+-----311..,..-----1-----+------l ·-"O .g c: 2.50 ...-----+-+---7'1'--~----t--3'...,.._-1-----+----~ 0 ~ g 2.00 ...----+--~c;__-+-----""-...d-----"''lo..:----+-----1 Q) Cl) Ol 1.50 ...---..,._-t-::;,,,C----+----t----=:::........::--t----"''7---+-----1 5 n l.OO "t"--'f--;r---t-----+-----+----t--~~~!!ok-------1 V) a o.5o ....--:"'7'----r-------r-----+-----+-----F,,,,,,,,._~::---'~ 0 .00 1"'----1------+----+-----+-----+---~ 0 5 10 15 20 25 Time (Minutes) Pre -D evelo pm e nt Hydrograph ---Post -Deve lo pment Outflow Hyd rograph Without Detentio n 11 30 Detention Pond De th Vs. Volume ~ Q) Q) u.. 1.60 1.40 1.20 1.00 ;; 0 .80 a. Q) a 0 .60 0 .40 0 .20 0.00 I I Ele vat ion Depth Volume (Feet) (Ft3) 323 .50 0 .00 0 32 3 .75 o.25 87 324 .00 0.50 416 324 .50 1.00 1,887 324 .75 1.25 2 ,894 325 .00 1.50 4 ,052 Detention Pond Depth Vs. Volume /~. / /~ v v ..... / v / v / O .~ lW 1~2 W2 ~3W3~4 W 4 ~ Detention Pond Volume (Cubic Feet) 12 Rating ~urve For Outlet Control Structure Pipe Dia . (Inches): 4 0.33 Depth Vs. Volume Pipe Length 11 .17 Feet Elevation Depth Discharge (Feet) Ft3/Sec 323.50 0.00 0.00 323 .75 0 .25 0.20 324 .00 0.50 0 .29 324.50 1.00 0.40 324 .75 1.25 0.45 325.00 1.50 0.49 Rating Curve For Outlet Control Structure Depth Vs. Volume 0 .00 0.10 0 .20 0.30 0.40 0 .50 Discharge (Cubic Feet Per Second) 13 I Storage Indication Curve Depth Storage Discharge 2s/t 2s/t+O (Feet) (Ft3) (Ft3/Sec) (Ft3/Sec) (Ft3/Sec) 0 .00 0 0 .00 0 .00 0.00 0.25 87 0 .20 2 .90 3 .10 0.50 416 0 .29 13.87 14.15 1.00 1 ,887 0.40 62 .90 63 .30 1.25 2 ,894 0.45 96.47 96.92 1.50 4 ,052 0.49 135.07 135.56 Storage Indication Curve 0.50 ~~ ~ ~ ~ /" 0 .45 0.40 ~ 0.35 0 0 Cl> (/) (D 0.30 I/ Q.. -Cl> Cl> u.. 0 0.25 :0 :J u -Cl> 0.20 O> 0 .c 0 '5 0.15 0.10 0.05 0.00 0 .00 ( I 20.00 40 .00 60.00 80 .00 100.00 120 .00 140.00 2s/t+O (Cubic Feet Per Second) 14 Inflow I Outflow Simulation 2-Year Storm Event Time Inflow 11+ 12 2s/t-O 2s/t+O Outflow Depth Elevation (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0.12 0.24 0.36 0.49 0.61 0.73 0.85 0.97 1.09 1.22 1.16 1.09 1.03 0.97 0.91 0.85 0.79 0.73 0.67 0.61 0.55 0.49 0.43 0.36 0.30 0.24 0.18 0.12 0.06 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.12 0.36 0.61 0.85 1.09 1.34 1.58 1.82 2.07 2.31 2.37 2.25 2.13 2.01 1.88 1.76 1.64 1.52 1.40 1.28 1.16 1.03 0.91 0.79 0.67 0.55 0.43 0.30 0.18 0.06 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.11 0.41 0.89 1.51 2.27 3.19 4.34 5.72 7.31 9.12 10.96 12.65 14.21 15.63 16.93 18.10 19.15 20.07 20.86 21.53 22.07 22.49 22.79 22.96 23.02 22.95 22.76 22.45 22.02 21.47 20.87 20.26 19.66 19.07 18.47 17.88 17.29 16.71 16.12 15.54 14.97 14.39 13.82 13.26 12.70 0.00 0.12 0.47 1.02 1.74 2.60 3.60 4.77 6.17 7.79 9.62 11.49 13.21 14.78 16.22 17.52 18.70 19.75 20.67 21.46 22.14 22.68 23.10 23.40 23.58 23.63 23.56 23.37 23.06 22.63 22.08 21.47 20.87 20.26 19.66 19.07 18.47 17.88 17.29 16.71 16.12 15.54 14.97 14.39 13.82 13.26 15 0.00 0.01 0.03 0.07 0.11 0.17 0.21 0.21 0.22 0.24 0.25 0.27 0.28 0.29 0.29 0.29 0.30 0.30 0.30 0.30 0.30 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.28 0.28 0.00 0.00 0.01 0.03 0.08 0.18 0.26 0.28 0.31 0.35 0.39 0.43 0.48 0.51 0.52 0.53 0.54 0.55 0.56 0.56 0.57 0.57 0.58 0.58 0.58 0.58 0.58 0.58 0.58 0.57 0.57 0.56 0.56 0.55 0.55 0.54 0.54 0.53 0.53 0.52 0.52 0.51 0.51 0.50 0.49 0.48 323.50 323.50 323.51 323.53 323.58 323.68 323.76 323.78 323.81 323.85 323.89 323.93 323.98 324.01 324.02 324.03 324.04 324.05 324.06 324.06 324.07 324.07 324.08 324.08 324.08 324.08 324.08 324.08 324.08 324.07 324.07· 324.06 324.06 324.05 324.05 324.04 324.04 324.03 324.03 324.02 324.02 324.01 324.01 324.00 323.99 323.98 Inflow/Outflow Simulation 2-Year Storm Event 2 .50 I " I " 2 .00 I " I " " I " ...... " "O I " c 0 I 0 I " QI en l.50 " ... " QI I " 0.. -I " QI I " QI LL. I " 0 " I :c " ~ u I " -l.00 ?; I " 0 I " E I' ' " I ' ~ ' 0 I / ' ' " I / " ' / ' " ' I 0 .5 0 ' " ' ' ' 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post --• -• -• Post- Developme Developme Develo pme Developme nt nt Outflow nt Outflow nt "Free- Hydrograph Hydrograph With Flow' Without Dete ntion Detention 16 Inflow I Outflow Simulation 5-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0.15 0.30 0.44 0.59 0.74 0.89 1.03 1.18 1.33 1.48 1.40 1.33 1.26 1.18 1.11 1.03 0.96 0.89 0.81 0.74 0.67 0.59 0.52 0.44 0.37 0.30 0.22 0.15 0.07 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.15 0.44 0.74 1.03 1.33 1.63 1.92 2.22 2.51 2.81 2.88 2.74 2.59 2.44 2.29 2.14 2.00 1.85 1.70 1.55 1.40 1.26 1.11 0.96 0.81 0.67 0.52 0.37 0.22 0.07 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.13 0.50 1.08 1.84 2.76 3.97 5.44 7.19 9.20 11.47 13.78 15.94 17.93 19.77 21.45 22.98 24.36 25.58 26.64 27.56 28.32 28.93 29.39 29.71 29.87 29.89 29.76 29.48 29.06 28.49 27.85 27.21 26.58 25.95 25.32 24.70 24.08 23.46 22.84 22.23 21.62 21.01 20.41 19.81 19.21 0.00 0.15 0.57 1.24 2.11 3.17 4.39 5.89 7.66 9.70 12.01 14.35 16.52 18.52 20.37 22.06 23.60 24.98 26.20 27.28 28.20 28.96 29.58 30.04 30.36 30.52 30.54 30.40 30.13 29.70 29.13 28.49 27.85 27.21 26.58 25.95 25.32 24.70 24.08 23.46 22.84 22.23 21.62 21.01 20.41 19.81 17 0.00 0.01 0.04 0.08 0.14 0.20 0.21 0.22 0.24 0.25 0.27 0.29 0.29 0.30 0.30 0.30 0.31 0.31 0.31 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.31 0.31 0.31 . 0.31 0.31 0.31 0.30 0.30 0.30 0.30 0.30 0.00 0.00 0.01 0.04 0.12 0.25 0.27 0.30 0.34 0.39 0.44 0.50 0.52 0.54 0.55 0.57 0.58 0.60 0.61 0.62 0.63 0.63 0.64 0.64 0.65 0.65 0.65 0.65 0.64 0.64 0.63 0.63 0.62 0.62 0.61 0.60 0.60 0.59 0.59 0.58 0.58 0.57 0.56 0.56 0.55 0.55 323.50 323.50 323.51 323.54 323.62 323.75 323.77 323.80 323.84 323.89 323.94 324.00 324.02 324.04 324.05 324.07 324.08 324.10 324.11 324.12 324.13 324.13 324.14 324.14 324.15 324.15 324.15 324.15 324.14 324.14 324.13. 324.13 324.12 324.12 324.11 324.10 324.10 324.09 324.09 324.08 324.08 324.07 324.06 324.06 324.05 324.05 3.00 2.50 :0 5 2.00 0 Cl> Cl) Q; 0.. -Cl> Cl> LL. 1.50 0 :0 ::::J u -~ 0 E ::::J 1.00 0 0.50 0.00 0 Inflow/Outflow Simulation 5-Year Storm Event I 5 Pre--- Developme nt Hydrograph I • I - I I I - I I I ' I 10 15 20 25 Time (Minutes) Post -Post -..... -....... Developme Developme nt Outflow nt Outflow Hydrograph With Without Detention Detention 18 30 Post- Developme nt "Free- Flow " Inflow I Outflow Simulation 10-Year Storm Event Time Inflow 11 + 12 2s/t-O 2s/t+O Outflow Depth Elevation (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0.17 0.33 0.50 0.66 0.83 1.00 1.16 1.33 1.49 1.66 1.58 1.49 1.41 1.33 1.24 1.16 1.08 1.00 0.91 0.83 0.75 0.66 0.58 0.50 0.41 0.33 0.25 0.17 0.08 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.17 0.50 0.83 1.16 1.49 1.83 2.16 2.49 2.82 3.15 3.24 3.07 2.90 2.74 2.57 2.41 2.24 2.07 1.91 1.74 1.58 1.41 1.24 1.08 0.91 0.75 0.58 0.41 0.25 0.08 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.14 0.56 1.21 2.06 3.14 4.54 6.24 8.24 10.54 13.13 15.78 18.26 20.56 22.68 24.63 26.41 28.01 29.43 30.69 31.77 32.69 33.43 34.01 34.41 34.65 34.73 34.64 34.38 33.96 33.38 32.72 32.06 31.40 30.75 30.10 29.45 28.80 28.16 27.53 26.89 26.26 25.63 25.01 24.38 23.76 0.00 0.17 0.64 1.39 2.37 3.56 4.97 6.70 8.73 11.06 13.69 16.36 18.85 21.16 23.30 25.26 27.04 28.65 30.08 31.34 32.43 33.35 34.10 34.68 35.09 35.33 35.40 35.31 35.05 34.63 34.04 33.38 32.72 32.06 31.40 30.75 30.10 29.45 28.80 28.16 27.53 26.89 26.26 25.63 25.01 24.38 19 0.00 0.01 0.04 0.09 0.15 0.21 0.22 0.23 0.24 0.26 0.28 0.29 0.30 0.30 0.31 0.31 0.32 0.32 0.32 0.33 0.33 0.33 0.33 0.33 0.34 0.34 0.34 0.34 0.34 0.33 0.33 0.33 0.33 0.33 0.33 0.33 0.32 0.32 0.32 0.32 0.32 0.32 0.31 0.31 0.31 0.31 0.00 0.00 0.01 0.05 0.15 0.26 0.29 0.32 0.37 0.42 0.49 0.52 0.54 0.56 0.58 0.60 0.61 0.63 0.64 0.66 0.67 0.67 0.68 0.69 0.69 0.69 0.70 0.69 0.69 0.69 0.68 0.68 0.67 0.66 0.66 0.65 0.64 0.64 0.63 0.63 0.62 0.61 0.61 0.60 0.60 0.59 323.50 323.50 323.51 3~3.55 323.65 323.76 323.79 323.82 323.87 323.92 323.99 324.02 324.04 324.06 324.08 324.10 324.11 324.13 324.14 324.16 324.17 324.17 324.18 324.19 324.19 324.19 324.20 324.19 324.19 324.19 324.18 324.18 324.17 324.16 324.16 324.15 324.14 324.14 324.13 324.13 324.12 324.11 324.11 324.10 324.10 324.09 Inflow/Outflow Simulation 10-Year Storm Event 3 .00 I ' I -I ' ... I ' I ' 2 .50 I ' I ' I ' I I ' ........ I ' "U 2.00 c 0 0 I Cl> V) ... Cl> Q.. -Cl> Cl> l.50 u.. 0 :0 :J u ....... ~ 0 E l.00 :J 0 0.50 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post -Post------·--Post- Developme Developme Deve lopme Developm e nt nt Outflow nt Outflow nt 'Free- Hydrograph Hydrograph With Flow' Without Detention Detention 20 T i me Inflow (Minutes) (Ft3/Sec) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0.19 0.38 0 .57 0 .76 0 .95 1.14 1.33 1.52 1.71 1.90 1.80 1.71 1.61 1.52 1.42 1.33 1 .23 1.14 1 .04 0.95 0.85 0.76 0 .66 0 .57 0.47 0.38 0 .28 0 .19 0.09 0 .00 0.00 0 .00 0.00 0.00 0 .00 0.00 0 .00 0 .00 0.00 0.00 0 .00 0.00 0 .00 0 .00 0.00 11+ 12 0 .00 0 .19 0 .57 0.95 1.33 1.71 2 .08 2.46 2.84 3 .22 3 .60 3 .70 3 .51 3.32 3 .13 2.94 2.75 2.56 2 .37 2 .18 1.99 1 .80 1 .61 1.42 1.23 1.04 0 .85 0.66 0.47 0 .28 0 .09 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0.00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 Inflow I Outflow Simulation 25-Year Storm Event 2s/t-0 0.00 0 .16 0.64 1 .38 2 .35 3 .64 5 .28 7 .27 9 .61 12.28 15.30 18.40 21 .30 24.00 26.49 28.79 30.88 32.78 34.48 35.98 37 .28 38 .39 39 .31 40.03 40.56 40.90 41 .05 41.01 40.79 40.37 39 .77 39 .07 38 .38 37 .70 37 .01 36 .33 35.66 34.98 34.31 33 .64 32 .98 32 .32 31.66 31 .01 30.36 29 .71 2s/t+O Outflow 0 .00 0 .19 0 .73 1.59 2 .71 4 .06 5.73 7.75 10.12 12 .83 15.88 19 .00 21.91 24.62 27.13 29.43 31 .54 33.44 35.15 36.66 37.97 39.08 40.00 40.73 41 .26 41 .61 41 .76 41.72 41.49 41 .07 40.46 39 .77 39.07 38.38 37.70 37.01 36.33 35.66 34.98 34.31 33.64 32.98 32 .32 31 .66 31 .01 30.36 21 (Ft3/Sec) 0.00 0 .01 0.05 0 .10 0.18 0 .21 0 .22 0.24 0 .25 0.28 0 .29 0.30 0 .30 0 .31 0 .32 0.32 0.33 0 .33 0.34 0 .34 0 .34 0 .35 0 .35 0 .35 0.35 0 .35 0 .35 0.35 0 .35 0 .35 0 .35 0 .35 0 .35 0 .34 0 .34 0 .34 0 .34 0 .34 0.34 0 .33 0 .33 0 .33 0 .33 0 .33 0.33 0 .32 Depth Elevation (Feet) 0 .00 0 .00 0 .01 0 .07 0.19 0.27 0 .30 0.34 0.40 0.47 0 .51 0 .54 0 .57 0.59 0.62 0 .64 0 .66 0 .68 0.69 0 .71 0 .72 0 .73 0.74 0 .75 0 .75 0 .76 0 .76 0 .76 0 .76 0 .75 0 .75 0.74 0 .73 0.73 0.72 0.71 0 .70 0 .70 0.69 0 .68 0.68 0.67 0.66 0.66 0 .65 0.65 323.50 323.50 323.51 323.57 323.69 323.77 323.80 323.84 323.90 323.97 324.01 324.04 324.07 324.09 324.12 324.14 324.16 324.18 324.19 324.21 324.22 324.23 324.24 324.25 324.25 324.26 324.26 324.26 324.26 324 .25 324.25 324 .24 324 .23 324 .23 324.22 324.21 324.20 324.20 324.19 324.18 324 .18 324.17 324.16 324 .16 324 .15 324 .15 Inflow/Outflow Simulation 25-Year Storm Event 3.50 I ' I ' ' I ' I .. I ' 3 .00 I ' I ' I ' ' I 2.50 ........ . . ' "O • ' c: 0 I ' 0 I "" Q) (/) ... Q) 2 .00 1:1.. -Q) Q) LL. 0 :.0 :::J l.50 u ..._, ~ 0 E :::J 0 l.00 I / "'-' I ' I ~ ' I ' I ' ii ' j ' I " ' ~ • ; .......... . ' ' --~ ' ' I ' ' ' ' I ' ' ' I ' ' ' ' I ' . ' . ' ' "" . ' ' -~ ·/.· ' . ' ' . ' ' ' ' I • • ' I • ' . i : ' ' "'-\ . ' . ·---~ ~ ',.... ' " ' .... .:' 0.50 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post--·-····· Post- Developme Developme Developme Developme nt nt Outflow nt Outflow nt "Free- Hydrograph Hydrograph With Flow " Without Detention Detention 22 Inflow I Outflow Simulation 50-Year Storm Event Time Inflow 11 + 12 2s/t-0 2s/t+O Outflow Depth Elevation (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0.21 0.43 0.64 0.86 1.07 1.29 1.50 1.71 1.93 2.14 2.04 1.93 1.82 1.71 1.61 1.50 1.39 1.29 1.18 1.07 0.96 0.86 0.75 0.64 0.54 0.43 0.32 0.21 0.11 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.21 0.64 1.07 1.50 1.93 2.36 2.79 3.21 3.64 4.07 4.18 3.96 3.75 3.54 3.32 3.11 2.89 2.68 2.46 2.25 2.04 1.82 1.61 1.39 1.18 0.96 0.75 0.54 0.32 0.11 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.19 0.72 1.56 2.66 4.16 6.07 8.36 11.04 14.11 17.59 21.16 24.51 27.62 30.50 33.16 35.59 37.79 39.77 41.53 43.07 44.38 45.48 46.36 47.02 47.46 47.69 47.71 47.51 47.10 46.48 45.75 45.03 44.31 43.59 42.88 42.17 41.47 40.77 40.07 39.37 38.68 37.99 37.31 36.63 35.95 0.00 0.21 0.83 1.79 3.06 4.59 6.52 8.85 11.57 14.69 18.18 21.77 25.13 28.25 31.15 33.82 36.26 38.48 40.47 42.24 43.78 45.10 46.20 47.09 47.75 48.20 48.43 48.44 48.24 47.83 47.20 46.48 45.75 45.03 44.31 43.59 42.88 42.17 41.47 40.77 40.07 39.37 38.68 37.99 37.31 36.63 23 0.00 0.01 0.05 0.12 0.20 0.21 0.23 0.25 0.27 0.29 0.29 0.30 0.31 0.32 0.33 0.33 0.34 0.34 0.35 0.35 0.36 0.36 0.36 0.36 0.37 0.37 0.37 0.37 0.37 0.37 0.36 0.36 0.36 0.36 0.36 0.36 0.35 0.35 0.35 0.35 0.35 0.35 0.34 0.34 0.34 0.34 0.00 0.00 0.02 0.08 0.24 0.28 0.32 0.37 0.43 0.50 0.53 0.57 0.60 0.63 0.65 0.68 0.70 0.73 0.75 0.76 0.78 0.79 0.81 0.82 0.82 0.83 0.83 0.83 0.83 0.82 0.82 0.81 0.80 0.79 0.79 0.78 0.77 0.76 0.76 0.75 0.74 0.74 0.73 0.72 0.71 0.71 323.50 323.50 323.52 323.58 323.74 323.78 323.82 323.87 323.93 324.00 324.03 324.07 324.10 324.13 324.15 324.18 324.20 324.23 324.25 324.26 324.28 324.29 324.31 324.32 324.32 324.33 324.33 324.33 324.33 324.32 324.32 324.31 324.30 324.29 324.29 324.28 324.27 324.26 324.26 324.25 324.24 324.24 324.23 324.22 324.21 324.21 Inflow/Outflow Simulation 50-Year Storm Event 4 .00 ,· ' I ' I ' 3.50 . . I ' I ... ' • ' 3.00 I .. • " I ' ........ 'U • ' c 0 0 2.50 Q) V> ... Q) Q.. -Q) Q) 2 .00 LL. 0 :.0 ::::J u -~ 1.50 0 s: ::::J 0 1.00 • ' • ' .. I I ~ ' . ' I ' I .. .. j I ""' ' I ~ ' • . ' ' . ' • . ' ' . ' . I . ' ' ~ .. I . ' ' ' . ' . ' ' • . ' , ' I , ' ~ ., • , ' ' , ' ' • , ' ' ' , ' . ·-.. ~ ' , ' ' ' ·!-' . ,' ' • ' , ' '\.. .. • ' ' I .. ... ... ""'" ' , ' , "~ ~ ', ' ......... ' 0.50 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post -Post--·------Post- Developme Developme Developme Developme nt nt Outflow nt Outflow nt "Free- Hydrograph Hydrograph With Flow" Without Detenti o n Detention 24 Inflow I Outflow Simulation 100-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0.22 0.45 0.67 0.89 1.12 1.34 1.57 1.79 2.01 2.24 2.13 2.01 1.90 1.79 1.68 1.57 1.45 1.34 1.23 1.12 1.01 0.89 0.78 0.67 0.56 0.45 0.34 0.22 0.11 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.22 0.67 1.12 1.57 2.01 2.46 2.91 3.36 3.80 4.25 4.36 4.14 3.91 3.69 3.47 3.24 3.02 2.80 2.57 2.35 2.13 1.90 1.68 1.45 1.23 1.01 0.78 0.56 0.34 0.11 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.19 0.75 1.63 2.79 4.37 6.37 8.79 11.60 14.83 18.48 22.23 25.74 29.01 32.05 34.84 37.40 39.72 41.81 43.67 45.29 46.69 47.85 48.79 49.50 49.98 50.24 50.28 50.09 49.68 49.05 48.31 47.58 46.85 46.12 45.40 44.68 43.96 43.25 42.53 41.83 41.12 40.42 39.73 39.03 38.34 0.00 0.22 0.87 1.87 3.19 4.80 6.83 9.28 12.14 15.40 19.08 22.85 26.37 29.66 32.70 35.51 38.08 40.42 42.52 44.38 46.02 47.42 48.59 49.53 50.24 50.73 50.99 51.03 50.84 50.43 49.79 49.05 48.31 47.58 46.85 46.12 45.40 44.68 43.96 43.25 42.53 41.83 41.12 40.42 39.73 39.03 25 0.00 0.01 0.06 0.12 0.20 0.21 0.23 0.25 0.27 0.29 0.30 0.31 0.31 0.32 0.33 0.34 0.34 0.35 0.35 0.36 0.36 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.36 0.36 0.36 0.36 0.36 0.36 0.35 0.35 0.35 0.35 0.35 0.35 0.00 0.00 0.02 0.09 0.25 0.28 0.32 0.38 0.45 0.51 0.54 0.58 0.61 0.64 0.67 0.70 0.72 0.75 0.77 0.79 0.80 0.82 0.83 0.84 0.85 0.86 0.86 0.86 0.86 0.85 0.85 0.84 0.83 0.82 0.81 0.81 0.80 0.79 0.78 0.78 0.77 0.76 0.75 0.75 0.74 0.73 323.50 323.50 323.52 323.59 323.75 323.78 323.82 323.88 323.95 324.01 324.04 324.08 324.11 324.14 324.17 324.20 324.22 324.25 324.27 324.29 324.30 324.32 324.33 324.34 324.35 324.36 324.36 324.36 324.36 324.35 324.35 324.34 324.33 324.32 324.31 324.31 324.30 324.29 324.28 324.28 324.27 324.26 324.25 324.25 324.24 324.23 Inflow/Outflow Simulation 100-Year Storm Event 4.50 4 .00 ' I ' I ' • .... ' 3 .50 . .... I .... I .... I .... ,... "O 3.00 c 0 I ' I' I 0 Q) .... . .... (/) ... I .... Q) 0... 2 .50 -Q) Q) u.. 0 :.0 2.00 ::> u -?; 0 E 1.50 ::> 0 l.00 I .... I I ~ ' I .... I .... .... I .... I " I' I ~ ' I . ' .... . ' ' .... I . ' . . ' .... I . ' I . ' ' "" ' I . ' ' . ' I . ' ' I . ' ' ~ I , ' .... . ' ' I . ' ' .... . ' ;· ' ' ··-.. ~ . .... ' I ,' ' . I ' " .... . '· :;· ' "-'~ .. . ·--~ ~ ''' ,: 0 .50 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post -............. Post- Developme Developme Developme Developme nt nt Outflow nt Outflow nt 'Free- Hydrograph Hydrograph Wit h Flow' Without Detention Detention 26 Inflow/Outflow Simulation 2-Year Storm Event 0 5 10 15 20 25 30 35 40 45 Time (Minutes) Pre-Development Hydrograph ----To tal Post-Development Hydrograph 27 Inflow/Outflow Simulation 5-Year Storm Event 1.80 ........ 1.20 "O c 0 0 Cl) (I) ... Cl) l.00 0.. -Cl) Cl) ..... 0 :0 0 .80 ::I u ....., ~ 0 E ::I 0 0.60 ,\ / ~\ II ~\ if ~ , ' \ \\ \ \ \ \ ' \ 1.60 l.40 0.40 0 .20 0.00 0 5 10 15 20 25 30 35 40 45 Time (Minutes) ---Pre-Development Hydrograph ---Total Post-Development Hydrograp h 28 ......... "O c 0 0 2.00 l .80 1.60 l.40 c9! l .20 Q) ll.. Qi Cl> u.. l .00 0 :0 ::::J () .._, ~ 0.8 0 0 E ::::J 0 0.60 0.4 0 0 .20 0.00 I 0 Inflow/Outflow Simulation 10-Year Storm Event 1\ I \ II \\ II \ ~ if \ , \~ \\ \ \ \\ \' \ 5 10 15 20 25 30 35 40 45 Time (Minutes) Pre-Development Hydrograph ---Total Post -Development Hydrograph 29 Inflow/Outflow Simulation 25-Year Storm Event 2 .50 2 .00 ........ "O c 0 0 Cl) 1.50 (f) ... Cl) CL -Cl) Cl) u.. 0 :0 :::J u .._, ~ 1.00 0 5: :::J 0 0.50 0 .00 0 5 10 15 20 25 30 35 40 45 Time (Minutes) Pre-Development Hydrograph ----Tota l Post-Development Hydrograph 30 Inflow/Outflow Simulation 50-Year Storm Event 2.50 2.00 ....... "O c: 0 0 Cl> 1.50 (/) ... Cl> 0.. -Cl> Cl> u.. 0 :0 :::J u .._, ~ l.00 0 s: :::J 0 0.50 0 .00 0 5 10 15 20 25 30 35 40 45 Time (Minutes) ---Pre-Development Hydrograph ----Tot a l Post-Develo pment Hyd rogra ph 31 Inflow/Outflow Simulation 100-Year Storm Event ....... 2.00 "O c 0 0 Q) V) ... Q) 0.. -Q) Q) l .50 ~ 0 :0 ::I u -?; 0 E ::I 0 l.00 0 5 10 15 20 25 30 35 40 45 Time (Minutes) ---Pre-Development Hydr o graph Tota l Post -De velopment Hydrograph 32 Detention Pond Storage Volumes as Percent of Maximu m Volume 100% 90% 80 % 70% Q) E :J 0 60% > E :J E ")( 50% 0 :E -0 -40% c Q) 0 ... Q) Q.. 30% 20% 10% 0% 2-year 5-year 10-year 25-year 50-year 100 -year Design Storm 50-ea r 100-ear Storm Depth 0.83 0 .86 Storm Elevatio n 324 .08 324 .15 324.2 0 324 .26 324 .33 324 .36 St o rm Volume 660 85 0 99 0 1180 1389 1472 Maxim um Capacity 4052 4052 4052 4052 4052 4052 Perce nt of Capa c ity 16% 21% 24% 29% 34% 36% 33 DRAINAGE COMPUTATIONS for Detention Pond 11 B 11 -Summit Street Four-Plexes being Lots 1R-4R Of A Replat Of Block 14A So uth wood Va ll ey -Sec tion 19 College Station , Brazos County, Texas Pr epared for Mr. Tony Jones 44 75 Hicks Lane College Sta ti on , Texas 77845 Pr epared bv: Garrett Engineering 4444 Ca rter Creek Parkway -Suite 108 Bryan , Texas 77802 Telephone : (409) 846 -2688 * April, 1995 * Determine Total Pre-Development Peak Storm Water Discharge Rates Tributary Area ("A"): 0.88 Acres Pervious Area : 0.86 Ac res Impervious A rea: 0 .02 Acres Run-Off Coefficient ("C wt "): 0.41 Time Of Concentratio n ("T/c"): W oodland s: Low Elevation : High Elevation : Distance (Feet): Slope (%Grade): Velocity ("Vw"): Time : Pas t ure s: Low Elevation : High Elevation : Distance (Feet): Slope (% Grade): Velocity ("Vp "): Time : Pavem ent s: Low Elevation : High Elevation : Distance (Feet): Slope (%Grade): Velocity ("Vpave"): Time : Total Travel Time : Hourly Intensity Rates ("I"): 2-Yea r: 6.33 5-Year: 7 .69 10-Year: 8.63 25-Year: 9.86 50-Yea r: 11.15 100-Year: 11.64 Peak Disc ha rge Rate ("Q"): 2-Year: 2.30 5-Year: 2.80 10-Year: 3 .14 25-Year: 3 .59 50-Year: 4 .0 5 100-Year: 4.23 c = 0.40 C = 0.98 0.00 0 .00 0 .00 0.0 0 0 .00 Feet I Second 0.00 Minutes 0.00 0.00 0.00 0.00 0.00 Feet I Second 0 .00 Minutes 0 .00 0.00 0.00 0.00 0.00 Feet I Second 0.00 Minutes 10.00 Minutes Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Seco nd Cubic Feet I Second Cubic Feet I Seco nd Cubic Feet I Second Determine Post-development Peak Storm Water DischarQe (No Detention) Tributary Area ("A"): 0.88 Acres Pervious Ar ea: 0.53 Acres Impervious Area: 0.35 Acres Run-Off Coefficient ("Cwt"): 0.63 Time Of Co ncentration ("T/c"): 10 Minutes (Min) Hourly Intensity Rates ("I"): 2-Year : 6.33 5-Year: 7.69 10-Year: 8.63 25-Year: 9.86 50-Year: 11.15 100-Year: 11 .64 c 7' 0.40 C= 0.98 Inches I Hour Inc hes I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Peak Disc ha rge Rate ("O"): 2-Year: 3.5 1 Cubic Feet I Second 5-Year: 4 .27 Cubic Feet I Second 10-Year: 4.79 Cubic Feet I Second 25-Year: 5.47 Cubic Feet I Second 50-Year: 6.19 Cubic Feet I Second 100-Year: 6.46 Cubic Feet I Second Comparison Of Predevelopment And Post -development Peak Discharge Rates Prede velopment Pos t-Development Increase 2-Year: 2.30 Ft3/sec 3.5 1 Ft3/sec 1.2 1 Ft3/sec 5-Year: 2 .80 Ft3/sec 4.27 Ft3/sec 1 .4 7 Ft3/sec 10-Yea r: 3 .14 Ft3/sec 4.79 Ft3/sec 1.65 Ft3/sec 25-Year: 3 .59 Ft3/sec 5.47 Ft3 /sec 1 .89 Ft3/sec 50-Year: 4.05 Ft3/sec 6.19 Ft3/sec 2.13 Ft3/sec 100-Year: 4.23 Ft3/sec 6.46 Ft3 /s ec 2.23 Ft3/sec Preliminary Determination Of Detention Pond Volume 2-Year: 1.21 Ft3/sec x (30 Min . x 60 Sec. I 2 ) = 1,090 Cub ic 5-Year: 1 .4 7 Ft3/sec x (30 Min. x 60 Sec . I 2 ) = 1,325 Cubic 10-Year: 1.65 Ft3/sec x (30 Min. x 60 Sec . I 2 ) = 1,487 Cubic 25-Year: 1.89 Ft3/sec x (30 Min. x 60 Sec. I 2 ) = 1,699 Cubic 50-Year: 2.13 Ft3/sec x (30 Min . x 60 Sec . I 2 ) = 1,92 0 Cubic 100-Year: 2.23 Ft3/sec x (30 Min . x 60 Sec. I 2 ) = 2 ,005 Cubic 2 Feet Feet Feet Feet Feet Feet Determine Post-Development "Free -Flow " Peak Storm Water Discharge Tributary A rea ("A"): 0 .38 Acres Pervious Area : 0.14 Acres Impervious Area : 0.24 Acres Run-Off Co efficient ("Cwt"): 0.77 T ime Of Co ncentration ("T/c"): 10 Minutes (Min) Hourly In tensity Rates ("I"): 2-Year: 6.33 5-Year : 7.69 10-Year: 8.63 25-Year: 9.86 50-Year: 11 .15 100-Year: 11 .64 Peak Dis ch arge Ra t e ("O"): 2-Yea r: 1.84 5-Year : 2.24 10-Year: 2.51 25-Year: 2 .87 50-Year: 3 .25 100 -Year : 3.39 3 C= 0.40 c = 0.98 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Seco nd Cubic Feet I Second Cubic Feet I Second Cubic Feet I Sec ond Cubic Feet I Seco nd Cubic Feet I Second Determine Post-Development Flow Into Detention Pond Tributary A rea ("A"): 0 .50 Acres Pervious Area: 0 .35 Acres Impervious A rea : 0 .15 Acres Run-Off C oefficient ("Cwt"): 0.57 Time Of Co ncentration ("T/c"): 1 O Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 6.33 5-Year: 7.69 10-Year: 8.63 25-Year: 9.86 50-Year: 1 1.15 100-Yea r: 11.64 Peak Discharge Rate ("Q "): 2-Year: 1.82 5-Year: 2 .2 1 10-Year: 2.48 25-Year: 2.83 50-Year: 3 .20 100-Year: 3 .34 4 c = 0.40 c = 0 .98 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Sec o nd Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Seco nd Pre-Development Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year {Minutes} Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.23 0.28 0.31 0.36 0.41 0.42 2 0.46 0.56 0.63 0.72 0.81 0.85 3 0.69 0.84 0.94 1.08 1.22 1.27 4 0.92 1.12 1.26 1.43 1.62 1.69 5 1.15 1.40 1.57 1.79 2.03 2.12 6 1.38 1.68 1.88 2.15 2.43 2.54 7 1.61 1.96 2.20 2.51 2.84 2.96 8 1.84 2.24 2.51 2.87 3.24 3.39 9 2.07 2.52 2.83 3.23 3.65 -----. I Peak=> 10 2.30 -_b.80 -3.14 3.59 4.05 11 2.19 2.66 2.98 3.41 3.85 4.02 12 2.07 2.52 2.83 3.23 3.65 3.81 13 1.96 2.38 2.67 3.05 3.45 3.60 14 1.84 2.24 2.51 2.87 3.24 3.39 15 1.73 2.10 2.35 2.69 3.04 3.17 16 1.61 1.96 2.20 2.51 2.84 2.96 17 1.50 1.82 2.04 2.33 2.63 2.75 18 1.38 1.68 1.88 2.15 2.43 2.54 19 1.27 1.54 1.73 1.97 2.23 2.33 20 1.15 1.40 1.57 1.79 2.03 2.12 21 1.04 1.26 1.41 1.61 1.82 1.90 22 0.92 1.12 1.26 1.43 1.62 1.69 23 0.81 0.98 1.10 1.25 1.42 1.48 24 0.69 0.84 0.94 1.08 1.22 1.27 25 0.58 0.70 0.78 0.90 1.01 1.06 26 0.46 0.56 0.63 0.72 0.81 0.85 27 0.35 0.42 0.47 0.54 0.61 0.63 28 0.23 0.28 0.31 0.36 0.41 0.42 29 0.12 0.14 0.16 0.18 0.20 0.21 30 0.00 0.00 0.00 0.00 0.00 0.00 5 Post-Development Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.35 0.43 0.48 0.55 0.62 0.65 2 0.70 0.85 0.96 1.09 1.24 1.29 3 1.05 1.28 1.44 1.64 1.86 1.94 4 1.40 1.71 1.92 2.19 2.47 2.58 5 1.76 2.13 2.40 2.74 3.09 3.23 6 2.11 2.56 2.88 3.28 3.71 3.88 7 2.46 2.99 3.35 3.83 4.33 4.52 8 2.81 3.42 3.83 4.38 4.95 5.17 9 3.16 3.84 4.31 4.93 cw ----·--------Peak=> 3.5L __ 4.27 4.79 -5.£_ --11 3.34 4.06 4.55 5.20 5.88 6.14 12 3.16 3.84 4.31 4.93 5.57 5.81 13 2.98 3.63 4.07 4.65 5.26 5.49 14 2.81 3.42 3.83 4.38 4.95 5.17 15 2.63 3.20 3.59 4.10 4.64 4.84 16 2.46 2.99 3.35 3.83 4.33 4.52 17 2.28 2.78 3.11 3.56 4.02 4.20 18 2.11 2.56 2.88 3.28 3.71 3.88 19 1.93 2.35 2.64 3.01 3.40 3.55 20 1.76 2.13 2.40 2.74 3.09 3.23 21 1.58 1.92 2.16 2.46 2.78 2.91 22 1.40 1.71 1.92 2.19 2.47 2.58 23 1.23 1.49 1.68 1.92 2.17 2.26 24 1.05 1.28 1.44 1.64 1.86 1.94 25 0.88 1.07 1.20 1.37 1.55 1.61 26 0.70 0.85 0.96 1.09 1.24 1.29 27 0.53 0.64 0.72 0.82 0.93 0.97 28 0.35 0.43 0.48 0.55 0.62 0.65 29 0.18 0.21 0.24 0.27 0.31 0.32 30 0.00 0.00 0.00 0.00 0.00 0.00 6 Post-Development "Free-Flow" Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 0.18 0.22 0.25 0.29 0.32 0.34 2 0.37 0.45 0.50 0.57 0.65 0.68 3 0.55 0.67 0.75 0.86 0.97 1.02 4 0.74 0.90 1.01 1.15 1.30 1.36 5 0.92 1.12 1.26 1.44 1.62 1 .69 6 1 .11 1.34 1.51 1.72 1.95 2.03 7 1 .29 1.57 1.76 2.01 2.27 2.37 8 1.47 1.79 2.01 2.30 2.60 2.71 9 1.66 2.02 2.26 2.58 2.92 [ -- --Peak=> 10 __ 1.M._ 2.24 2.51 2.87 ---21§ -11 1.75 2.13 2.39 2.73 3.08 3.22 12 1.66 2.02 2.26 2.58 2.92 3.05 13 1.57 1.90 2.14 2.44 2.76 2.88 14 1.47 1.79 2.01 2.30 2.60 2.71 15 1.38 1.68 1.89 2.15 2.43 2.54 16 1.29 1.57 1.76 2.01 2.27 2.37 17 1.20 1.46 1.63 1.87 2.11 2.20 18 1 .11 1.34 1.51 1.72 1.95 2.03 19 1.01 1.23 1.38 1.58 1.79 1.86 20 0.92 1.12 1.26 1.44 1.62 1 .69 21 0.83 1.01 1.13 1.29 1.46 1.53 22 0.74 0.90 1.01 1.15 1.30 1.36 23 0.64 0.78 0.88 1.01 1.14 1.19 24 0.55 0.67 0.75 0.86 0.97 1.02 25 0.46 0.56 0.63 0.72 0.81 0.85 26 0.37 0.45 0.50 0.57 0.65 0.68 27 0.28 0.34 0.38 0.43 0.49 0.51 28 0.18 0.22 0.25 0.29 0.32 0.34 29 0.09 0.11 0.13 0.14 0.16 0.17 30 0.00 0.00 0.00 0.00 0.00 0.00 7 Post-Development Flow Routed Through Detention Pond Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.18 0.22 0.25 0.28 0.32 0.33 2 0.36 0.44 0.50 0.57 0.64 0.67 3 0.54 0.66 0.74 0.85 0.96 1.00 4 0.73 0.88 0.99 1.13 1.28 1.34 5 0.91 1.10 1.24 1.42 1.60 1.67 6 1.09 1.32 1.49 1.70 1.92 2.00 7 1.27 1.55 1.73 1.98 2.24 2.34 8 1.45 1.77 1.98 2.26 2.56 2.67 9 1.63 1.99 2.23 2.55 2.88 3.01 --~ -. -. 3.20 ~ 3.34 Peak=> I 10 1.82 2.21 2.48 2.83 ---------11 1.72 2.10 2.35 2.69 3.04 3.17 12 1.63 1.99 2.23 2.55 2.88 3.01 13 1.54 1.88 2.11 2.41 2.72 2.84 14 1.45 1.77 1.98 2.26 2.56 2.67 15 1.36 1.66 1.86 2.12 2.40 2.51 16 1.27 1.55 1.73 1.98 2.24 2.34 17 1.18 1.44 1.61 1.84 2.08 2.17 18 1.09 1.32 1.49 1.70 1.92 2.00 19 1.00 1.21 1.36 1.56 1.76 1.84 20 0.91 1.10 1.24 1.42 1.60 1.67 21 0.82 0.99 1.12 1.27 1.44 1.50 22 0.73 0.88 0.99 1.13 1.28 1.34 23 0.64 0.77 0.87 0.99 1.12 1.17 24 0.54 0.66 0.74 0.85 0.96 1.00 25 0.45 0.55 0.62 0.71 0.80 0.84 26 0.36 0.44 0.50 0.57 0.64 0.67 27 0.27 0.33 0.37 0.42 0.48 0.50 28 0.18 0.22 0.25 0.28 0.32 0.33 29 0.09 0.11 0.12 0.14 0.16 0.17 30 0.00 0.00 0.00 0.00 0.00 0.00 8 a; ~ "$ Q) u.. Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 2-Year Storm Event 0" 2 .50 -------+--------<------+-""~---+-------<-------< ·-'O .0 c 8 8 2 .00 +-----+-#---7"-'-----i-----"......,,..-+---"""'""--+-------t-------t ....., Q) & (I) l .50 +---~H----,,c..__----t----+--""'-.:::----+--c-------t-------t 5 .t:. ~ 0 0 5 10 15 20 25 Time (Minutes) Pre-Development Hydrograph Total Post-Development Hydrograph Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 5-Year Storm Event 30 4 .50 -------.-------.-----r------.-------.---~ :. 4 .00 -----+-----l-t--"O..-----+-----+--------l------1 "$ 3.50 +------+----1----t----.30-+------+-------t-------I Q) ~ ..... 3 .00 -----+-------t-----t--"----+--------l------1 ·-'O .g c 2 .50 +------t--f---?L....-f-=-...c-----+----3""7--4------1-------l u 0 ; ~ 2.00 O'> 1.50 ...---.,-_,,..~-----t----+---~~---"'""7----t-------1 5 n l .oo ...---:_,__r----r--------+-----t------+--~~---4....._------l II) 0 0 .5 0 T"""""";~---t-------r-----t-----j----t--==-......::"""---1 0 .00 'f"-----41------+----+-----+----+---~ 0 5 10 15 20 25 Time (Minutes) Pre-Development Hydrograph ---Post-Development Outflow Hydrograph Without Detention 9 30 5 .00 ... 4 .50 Q) 0.. 4.00 -Q) Q) 3 .50 LL. .~ 1J 3 .00 .D c 8 8 2.50 -Q) 2 .00 Q) (/) Ol ... 1.50 0 .s::. 0 l.00 ~ a 0 .50 0 .00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 10-Year Storm Eve nt 5 10 15 20 25 Time (Minutes) 30 ---Pre-Development Hydrograph ----Post-Development Outflow Hydrograph Without Detention 6 .00 ... Q) 5.00 0.. -Q) Q) 4 .00 LL. 0 ...... ·-"O .D c :> 0 3.00 u 0 -Q) Q) Cl) Ol 2.00 ... 0 .s::. 0 ~ l.00 a 0 .00 0 Total Pre -Development Vs . Total Post-Development (No Detention) Peak Discharge Rates 25-Year Storm Event 5 10 15 20 25 Ti me (Minutes) 30 Pre-Development Hydrograph ----Post-Development Outflow Hydrograph Without Detention 10 7.00 ... 6.0 0 Q) 0.. -Q) 5.00 Q) u.. 0 ........ :.0 -g 4.00 :J 0 u 0 3.00 ....... Q) Q) (f) 0) ... 2.00 0 .&::. 0 VI 1.00 i5 0.00 0 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 50-Year Storm Event 5 10 15 20 25 Time (Minutes) 30 Pre-Development Hydrograph ---Post-Development Outflow Hydrograph Wi t hout Detention Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 100-Year Storm Event Q; 0.. 6.00 +-----+----~--"....,_--+-----+-------l-------1 Q; ~ 5 .oo ...-----r--~-----t---~..i-----r------1------j 0 ........ :.0 -g 4.0 0 +-----+-F---rt..=.....::---+--~--+-----1---------.j :J 0 u 0 ....... Q) 3.00 't'-------;i~-----:;.,,C----+----+"""""-=--------1~,----+------l Q) (f) 0) 0 2.00 't'--~'---::;""1-----+----+--------=i=--.....:----=:!....,_+------l .&::. 0 3 1.00 1'--F.T-----t-------ir----+-----t------=~~~-----i 0.00 'f'----1------+----+-----+----+---~ 0 5 10 15 20 25 Time (Minutes) Pre-Development Hydrograph 11 Post-Development Outflow Hydrograph Without Detention 30 Detention Pond De t h Vs. Volume 1.40 1.20 1.00 i 0.80 Q) LL '"" .i:::. -a. Q) 0 0.60 0.4 0 0.2 0 0 Elevatio n Dept h Vo lume (Feet) (Ft3) 324.80 0 .00 0 325.00 0 .2 0 11 1 325.25 0.45 714 325 .50 0.70 1,951 325 .75 0 .95 3,818 326 .13 1.33 6 ,321 Detention Pond Depth Vs. Volume 1,000 2,000 3,000 4,000 5,000 6,000 7,000 Detention Pond Volume (Cubic Feet) 12 Rating Curve For Outlet Control Structure Pipe Dia . (Inches): 4 De th Vs. Vo l ume Pipe Length 12.00 Elevation Depth Discharge (Feet ) Ft3/S ec 324 .80 0 .00 0.0 0 325 .00 0 .20 0 .18 325 .25 0.45 0 .27 325 .50 0.7 0 0 .33 325.75 0.95 0.39 326 .13 1.33 0.46 Rating Curve For Outlet Control Structure Depth Vs . l.00 i 0.80 CJ) LI.. ....... ~ a. Volume 0.33 Feet ~ 0 .60 ~-----l---------+------11----___. ____ ___J 0.20 0 .00 0 .00 0 .10 0 .20 0 .30 0 .40 0 .50 Discharge (Cubic Feet Per Se cond) 13 I Storage Ind ication Curve Depth Sto rage D is charg e 2s/t 2s/t+O (Feet) (Ft3) (Ft3 /Sec) (Ft3/Sec) (Ft3/Sec) 0.0 0 0 0 .00 0.00 0 .00 0 .20 111 0.18 3.7 0 3.88 0.45 714 0.27 23 .80 24 .07 0.70 1 ,951 0 .33 65.03 65 .36 0 .95 3 ,818 0 .39 127.27 127.65 1.33 6 ,321 0.46 210 .70 211 .16 Storage Indication Curve 0 .50 0.45 0 .40 ........ "O 0.35 c 0 0 ~ ... 0 .30 (I) ll.. -(I) (I) ~ 0 .25 0 :0 ::J u ......, (I) 0.20 0) ... 0 ~ ./ ~ / ./ / I I ..c 0 '5 0 .15 0 .10 0.05 0 .00 0 .00 50 .00 100 .00 150 .00 200 .00 250 .00 2s/t+O (C u b ic Feet Pe r Second) 14 Time Inflow (Minutes) (Ft3/Sec) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0.18 0.36 0.54 0.73 0.91 1.09 1.27 1.45 1.63 1.82 1.72 1.63 1.54 1.45 1.36 1.27 1.18 1.09 1.00 0.91 0.82 0.73 0.64 0.54 0.45 0.36 0.27 0.18 0.09 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 11+ 12 0.00 0.18 0.54 0.91 1.27 1.63 2.00 2.36 2.72 3.09 3.45 3.54 3.36 3.18 3.00 2.81 2.63 2.45 2.27 2.09 1.91 1.72 1.54 1.36 1.18 1.00 0.82 0.64 0.45 0.27 0.09 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Inflow I Outflow Simulation 2-Year Storm Event 2s/t-0 0.00 0.16 0.64 1.41 2.44 3.72 5.34 7.31 9.63 12.28 15.28 18.33 21.18 23.83 26.28 28.55 30.63 32.52 34.22 35.74 37.07 38.22 39.18 39.96 40.55 40.97 41.19 41.24 41.11 40.79 40.30 39.72 39.14 38.56 37.98 37.40 36.83 36.26 35.69 35.12 34.55 33.99 33.43 32.86 32.31 31.75 2s/t+O Outflow 0.00 0.18 0.71 1.55 2.68 4.07 5.71 7.70 10.04 12.72 15.73 18.82 21.69 24.36 26.82 29.10 31.18 33.08 34.79 36.31 37.65 38.80 39.76 40.54 41.14 41.55 41.78 41.83 41.70 41.38 40.89 40.30 39.72 39.14 38.56 37.98 37.40 36.83 36.26 35.69 35.12 34.55 33.99 33.43 32.86 32.31 15 (Ft3/Sec) 0.00 0.01 0.03 0.07 0.12 0.18 0.19 0.19 0.20 0.22 0.23 0.24 0.26 0.27 0.27 0.27 0.28 0.28 0.28 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.28 0.28 0.28 0.28 0.28 0.28 0.28 Depth Elevation (Feet) 0.00 0.00 0.01 0.03 0.10 0.20 0.22 0.24 0.27 0.30 0.33 0.38 0.42 0.45 0.46 0.48 0.49 0.50 0.51 0.52 0.53 0.53 0.54 0.54 0.55 0.55 0.55 0.55 0.55 0.55 0.55 0.54 0.54 0.53 0.53 0.53 0.52 0.52 0.52 0.51 0.51 0.51 0.51 0.50 0.50 0.50 324.80 324.80 324.81 324.83 324.90 325.00 325.02 325.04 325.07 325.10 325.13 325.18 325.22 325.25 325.26 325.28 325.29 325.30 325.31 325.32 325.33 325.33 325.34 325.34 325.35 325.35 325.35 325.35 325.3!:; 325.35 325.35 325.34 325.34 325.33 325.33 325.33 325.32 325.32 325.32 325.31 325.31 325.31 325.31 325.30 325.30 325.30 Inflow/Outflow Simulation 2-Year Storm Event 4 .00 3 .50 I ' I ... I ' ... I ' 3.00 . ' I ' • ... ........ "O c I ' 0 I 0 2.50 Q) ' • ... en ... I ' Q) Q. -Q) Q) 2 .00 ... 0 :0 ::::J 0 ...,., ~ l.50 0 = ::::J 0 l.00 I I ~ ... I ' I ... ' ... /,. 1',, ~ ... ' ~ I I ' ' I / ' ·, ... I V/' ' ""'-~ ' ' ... I " I ... : J ' "" ' I '· ... ·) .. ' '·~ ,. I ' I ... I ' I ' ... I ,~, . '' ... '/ -~ I ' ... ~ ' 0.50 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post--• -• -• Post- Developme Developme Developme Developme nt nt Outflow nt Outflow nt "Free- Hydrograph Hydrograph With Flow' Without Detention Detenti o n 16 Time Inflow (Minutes) (Ft3/Sec) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0.22 0.44 0 .66 0 .88 1 .10 1.32 1.55 1.77 1.99 2 .21 2.10 1.99 1.88 1.77 1.66 1.55 1.44 1.32 1.21 1.10 0 .99 0 .88 0 .77 0 .66 0.55 0.44 0 .33 0 .22 0 .11 0.00 0 .00 0 .00 0.00 0.00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0.00 0 .00 0.00 0.00 0 .00 11+ 12 0 .00 0 .22 0 .66 1 .10 1 .55 1.99 2.43 2 .87 3 .31 3.75 4 .19 4 .31 4 .08 3 .86 3 .64 3.42 3 .20 2.98 2 .76 2 .54 2 .32 2 .10 1.88 1.66 1.44 1.21 0.99 0 .77 0 .55 0 .33 0.11 0 .00 0 .00 0 .00 0.00 0.00 0.00 0.00 0 .00 0.00 0 .00 0.00 0 .00 0 .00 0 .00 0.00 Inflow I Outflow Simulation 5-Year Storm Event 2s/t-0 0 .00 0 .20 0 .78 1.72 2 .96 4 .59 6.63 9.10 11 .98 15.28 18.98 22 .76 26 .31 29 .62 32 .70 35 .55 38 .18 40 .57 42 .74 44 .68 46 .39 47.88 49 .15 50 .19 51 .00 51.59 51 .97 52 .12 52 .05 51.76 51 .25 50 .63 50.01 49.40 48 .79 48 .18 47 .57 46.96 46 .36 45 .76 45 .16 44 .56 43.96 43 .37 42 .77 42 .18 2s/t+O Outflow 0.00 0.22 0 .86 1.89 3 .26 4 .95 7.02 9.50 12.41 15.74 19.47 23 .29 26 .85 30 .17 33 .26 36 .12 38 .76 41.16 43 .33 45.28 47.00 48.49 49.76 50 .80 51 .62 52.22 52 .59 52 .74 52 .67 52 .38 51 .87 51 .25 50 .63 50 .01 49.40 48 .79 48 .18 47.57 46 .96 46 .36 45.76 45.16 44 .56 43.96 43 .37 42 .77 17 (Ft3 /Sec) 0.00 0.01 0 .04 0 .09 0.15 0 .18 0 .19 0.20 0 .21 0 .23 0 .25 0 .26 0 .27 0.28 0 .28 0.28 0.29 0 .29 0.30 0.30 0 .30 0 .30 0 .31 0 .31 0 .31 0 .31 0 .31 0.31 0.31 0 .31 0 .31 0.31 0 .31 0 .31 0 .31 0.30 0 .30 0 .30 0.30 0.30 0.30 0.30 0 .30 0 .30 0 .30 0.30 Depth Elevation (Feet) 0 .00 0 .00 0 .01 0 .05 0 .14 0 .21 0 .23 0 .26 0 .29 0 .33 0 .38 0.44 0.47 0.48 0 .50 0 .52 0 .53 0 .55 0 .56 0 .57 0 .58 0.59 0.60 0 .61 0.61 0.61 0.62 0.62 0 .62 0.62 0.61 0.61 0.60 0 .60 0 .60 0 .59 0 .59 0.59 0 .58 0 .58 0 .57 0 .57 0 .57 0 .56 0.56 0.56 324.80 324.80 324 .81 324 .85 324.94 325 .01 325.03 325 .06 325 .09 325 .13 325.18 325.24 325 .27 325.28 325.30 325 .32 325 .33 325 .35 325 .36 325.37 325 .38 325 .39 325.40 325.41 325 .41 325.41 325.42 325.42 325.42 325.42 325.41 325.41 325.40 325.40 325.40 325 .39 325 .39 325 .39 325 .38 325.38 325 .37 325.37 325.37 325.36 325 .36 325 .36 Inflow/Outflow Simulation 5-Year Storm Event 4.50 I ' I ' --~ 4 .00 I ' I ' I ' ' 3.50 I ' . ' I ' I ~ ........ "O 3 .00 c 0 0 I ' I - ' I Cl> Cl) ... Cl> Q.. 2 .50 -Cl> Cl> LL. 0 :.0 2 .00 :J u -~ 0 E 1.50 :J 0 l.00 I ~ -I ' I ... . 7 .... ", ~ ' I ' I ' ' ', r-... ' • / .. / ' "~ ' I ' ' ' ' I ' ' ' ' I ' I ' I . ' ' '\ ' I . ~\ ' :'I . ' . ' . ' . " ·/: "·"~ ' " . I ' ' ~\ I ' . 1· ',:\_' . ' ' . -~ '',' 0 .50 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post-.... -. -. Post- Developme Developme Developme Developme nt nt Outflow nt Outflow nt "Free- Hydrograph Hydrograph Wi t h Flow· Without Detention Detention 18 Inflow I Outflow Simulation 10-Year Storm Event Time Inflow 11 + 12 2s/t-0 2s/t+O Outflow Depth Elevation (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0.25 0.50 0.74 0.99 1.24 1.49 1.73 1.98 2.23 2.48 2.35 2.23 2.11 1.98 1.86 1.73 1.61 1.49 1.36 1.24 1.12 0.99 0.87 0.74 0.62 0.50 0.37 0.25 0.12 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.25 0.74 1.24 1.73 2.23 2.73 3.22 3.72 4.21 4.71 4.83 4.58 4.34 4.09 3.84 3.59 3.35 3.10 2.85 2.60 2.35 2.11 1.86 1.61 1.36 1.12 0.87 0.62 0.37 0.12 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.23 0.88 1.93 3.33 5.19 7.52 10.33 13.60 17.34 21.54 25.83 29.86 33.63 37.15 40.40 43.40 46.15 48.63 50.86 52.84 54.56 56.04 57.25 58.22 58.94 59.41 59.63 59.61 59.33 58.81 58.17 57.53 56.89 56.26 55.62 54.99 54.36 53.73 53.11 52.48 51.86 51.24 50.62 50.01 49.40 0.00 0.25 0.97 2.12 3.66 5.56 7.91 10.74 14.05 17.82 22.05 26.37 30.41 34.20 37.72 40.99 44.00 46.75 49.24 51.48 53.46 55.19 56.67 57.89 58.87 59.59 60.06 60.28 60.25 59.98 59.46 58.81 58.17 57.53 56.89 56.26 55.62 54.99 54.36 53.73 53.11 52.48 51.86 51.24 50.62 50.01 19 0.00 0.01 0.04 0.10 0.17 0.18 0.19 0.21 0.22 0.24 0.26 0.27 0.28 0.28 0.29 0.29 0.30 0.30 0.31 0.31 0.31 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.00 0.00 0.01 0.06 0.18 0.22 0.24 0.27 0.31 0.36 0.42 0.46 0.48 0.51 0.53 0.55 0.56 0.58 0.60 0.61 0.62 0.63 0.64 0.65 0.66 0.66 0.66 0.67 0.67 0.66 0.66 0.66 0.65 0.65 0.64 0.64 0.64 0.63 0.63 0.62 0.62 0.62 0.61 0.61 0.60 0.60 324.80 324.80 324.81 324.86 324.98 325.02 325.04 325.07 325.11 325.16 325.22 325.26 325.28 325.31 325.33 325.35 325.36 325.38 325.40 325.41 325.42 325.43 325.44 325.45 325.46 325.46 325.46 325.47 325.47 325.46 325.46 325.46 325.45 325.45 325.44 325.44 325.44 325.43 325.43 325.42 325.42 325.42 325.41 325.41 325.40 325.40 5.00 4.50 4.00 ,.... 3.50 "O c 0 0 Cl> (f) 3 .00 (ij Q.. '$ Cl> LL. 2.50 0 :0 :J u ; 2.00 0 = :J 0 1.5 0 1.00 0.50 0.00 Inflow/Outflow Simulation 10-Year Storm Event ·"' I ' ~ I ' • ' I ' I ' I ' I . I ' ' I I ' I ' I 1t\. ' . ' 7 ~ ' • ' I ' I ' ,_ / .. / ',,, " .. ' ~ " ' ' I ' ' ' ' I ' ' ' ' • / ....... ' ------~ ' .. I ' I . I . '' 1'. ' :/. . ' ' -~\ . ' ' I ' . ' ' . ' ./: '" ,"\ . ' .. ' ~\ ' I ' ' I / ',\_' . ,, __,,,,,, 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post -Post ---------Post- Developme Developme Developme Developme nt nt Outflow nt Outflow nt 'F ree- Hydrograph Hydrograph Wit h Flow' Without Detention Detention 20 Inflow I Outflow Simulation 25-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0.28 0.57 0.85 1.13 1.42 1.70 1.98 2.26 2.55 2.83 2.69 2.55 2.41 2.26 2.12 1.98 1.84 1.70 1.56 1.42 1.27 1.13 0.99 0.85 0.71 0.57 0.42 0.28 0.14 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.28 0.85 1.42 1.98 2.55 3.11 3.68 4.25 4.81 5.38 5.52 5.24 4.95 4.67 4.39 4.10 3.82 3.54 3.25 2.97 2.69 2.41 2.12 1.84 1.56 1.27 0.99 0.71 0.42 0.14 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.26 1.01 2.20 3.82 5.99 8.71 11.96 15.74 20.05 24.89 29.86 34.53 38.90 42.98 46.76 50.25 53.44 56.34 58.95 61.27 63.31 65.05 66.50 67.68 68.56 69.17 69.49 69.52 69.28 68.75 68.08 67.41 66.75 66.08 65.42 64.75 64.09 63.43 62.78 62.12 61.47 60.82 60.17 59.53 58.88 0.00 0.28 1.11 2.42 4.18 6.37 9.11 12.39 16.20 20.55 25.43 30.41 35.10 39.48 43.57 47.37 50.87 54.07 56.98 59.60 61.93 63.96 65.71 67.17 68.34 69.23 69.84 70.16 70.19 69.95 69.42 68.75 68.08 67.41 66.75 66.08 65.42 64.75 64.09 63.43 62.78 62.12 61.47 60.82 60.17 59.53 21 0.00 0.01 0.05 0.11 0.18 0.19 0.20 0.21 0.23 0.25 0.27 0.28 0.28 0.29 0.30 0.30 0.31 0.31 0.32 0.32 0.33 0.33 0.33 0.33 0.33 0.33 0.34 0.34 0.34 0.34 0.33 0.33 0.33 0.33 0.33 0.33 0.33 0.33 0.33 0.33 0.33 0.33 0.33 0.32 0.32 0.32 0.00 0.00 0.02 0.08 0.20 0.23 0.26 0.29 0.34 0.40 0.46 0.48 0.51 0.54 0.56 0.58 0.61 0.63 0.64 0.66 0.68 0.69 0.70 0.71 0.71 0.71 0.72 0.72 0.72 0.72 0.72 0.71 0.71 0.71 0.71 0.70 0.70 0.70 0.69 0.69 0.68 0.68 0.67 0.67 0.67 0.66 324.80 324.80 324.82 324.88 325.00 325.03 325.06 325.09 325.14 325.20 325.26 325.28 325.31 325.34 325.36 325.38 325.41 325.43 325.44 325.46 325.48 325.49 325.50 325.51 325.51 325.51 325.52 325.52 325.52 325.52 325.52 325.51 325.51 325.51 325.51 325.50 325.50 325.50 325.49 325.49 325.48 325.48 325.47 325.47 325.47 325.46 6.00 5.00 ........ "C c 4.00 0 0 Cl> (/) ~ ll.. -Cl> Cl> ~ 3 .00 0 :0 ::::> u -~ 0 == ::::> 2.00 0 1.00 0 .00 0 Inflow /Outflow Simulation 25-Year Storm Event 5 Pre-- Developme nt Hydrograph - I I - I I I I I - I ' I ' ' ' ' ' ' ' ' 10 15 20 25 Time (Minutes) Post -Post--------- De velopme Developme nt Outflow nt Outflow Hydrograph With Wit h out Det enti on Detention 22 30 Post- Developme nt "Free- Flow" T i me Inflow (M i nutes) (Ft3/Sec) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0 .32 0 .64 0 .96 1.28 1 .60 1.92 2.24 2 .56 2 .88 3 .20 3 .04 2 .88 2 .72 2 .56 2.40 2 .24 2 .08 1 .92 1 .76 1 .60 1.44 1 .28 1 .12 0 .96 0 .80 0 .64 0.48 0 .32 0 .16 0 .00 0 .00 0.00 0 .00 0.00 0 .00 0 .00 0 .00 0.00 0.00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 11+ 12 0 .00 0 .32 0 .96 1.60 2 .24 2 .88 3 .52 4 .16 4 .80 5.44 6.08 6 .24 5.92 5 .60 5 .28 4.96 4 .64 4 .32 4 .00 3 .68 3 .36 3 .04 2 .72 2.40 2 .08 1.76 1.44 1.12 0 .80 0.48 0 .16 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 Inflow I Outflow Simulation 50-Year Storm Event 2s/t-O 0 .00 0 .29 1.14 2.49 4.36 6 .86 9 .97 13.68 18.00 22 .91 28.44 34 .12 39.45 44.46 49 .12 53.45 57.45 61.12 64.46 67.47 70 .16 72 .52 74 .56 76 .28 77 .67 78 .74 79.49 79 .92 80 .03 79 .82 79 .30 78 .61 77 .92 77 .24 76 .55 75 .87 75 .19 74.51 73 .83 73 .15 72.48 71 .80 71.13 70.46 69 .78 69.11 2s/t +O Outflow 0 .00 0 .32 1.25 2 .74 4 .73 7 .24 10.38 14.13 18.48 23.44 28.99 34.68 40 .04 45 .05 49 .73 54 .08 58 .09 61 .77 65 .12 68.14 70 .83 73.20 75 .24 76.96 78 .36 79.43 80.18 80 .61 80 .72 80 .51 79.98 79 .30 78.61 77 .92 77.24 76 .55 75 .87 75.19 74 .51 73 .83 73 .15 72.48 71 .80 71 .13 70.46 69.78 23 (Ft3/Sec) 0 .00 0.01 0.06 0.12 0 .18 0 .19 0 .21 0 .22 0 .24 0 .26 0.27 0.28 0.29 0.30 0.31 0 .31 0 .32 0 .33 0 .33 0.33 0 .34 0.34 0 .34 0.34 0 .34 0 .34 0 .34 0.34 0 .34 0 .34 0 .34 0.34 0 .34 0 .34 0 .34 0 .34 0 .34 0 .34 0 .34 0 .34 0 .34 0 .34 0.34 0 .34 0.34 0 .34 Depth Elevation (Feet) 0 .00 0.00 0 .02 0.10 0 .21 0 .23 0.27 0.31 0.37 0.44 0.48 0 .51 0.54 0 .57 0 .60 0.63 0 .65 0 .68 0 .70 0 .71 0.72 0 .73 0 .74 0.74 0 .75 0 .75 0 .76 0.76 0 .76 0 .76 0 .76 0 .75 0.75 0 .75 0 .74 0 .74 0 .74 0 .74 0 .73 0 .73 0 .73 0.73 0 .72 0 .72 0.72 0 .72 324 .80 324.80 324.82 324 .90 325 .01 325 .03 325 .07 325 .11 325.17 325.24 325.28 325.31 325.34 325.37 325.40 325.43 325.45 325.48 325 .50 325 .51 325 .52 325 .53 325 .54 325.54 325.55 325 .55 325 .56 325.56 325 .56 325 .56 325.56 325 .55 325 .55 325 .55 325 .54 325 .54 325.54 325 .54 325 .53 325 .53 325.53 325 .53 325 .52 325 .52 325 .52 325 .52 B c::: 0 0 Cl> Cl) 7.00 6.00 5 .00 :. 4 .00 Qi Cl> LL. 0 :0 §. 3.00 ~ 0 ~ :::> 0 2 .00 l.00 0 .00 Inflow/Outflow Simulation 50-Year Storm Event I I I I I I I I I I ... .... ... .... ... ... ' /j~ .... .... .... .... " -,;~ ·-~, 1·~ -~ 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post -Post ---------Post- Developme Developme Developme Developm e nt nt Outflow nt O utflow nt 'Free- Hy dr ogra ph Hydrograph With Flow' Without Detention Detention 24 Inflow I Outflow Simulation 100-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation (Minutes) (Ft3/Sec) (Ft3/Sec) (Feet) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0.33 0.67 1.00 1.34 1.67 2.00 2.34 2.67 3.01 3.34 3.17 3.01 2.84 2.67 2.51 2.34 2.17 2.00 1.84 1.67 1.50 1.34 1.17 1.00 0.84 0.67 0.50 0.33 0.17 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.33 1.00 1.67 2.34 3.01 3.67 4.34 5.01 5.68 6.35 6.51 6.18 5.85 5.51 5.18 4.84 4.51 4.18 3.84 3.51 3.17 2.84 2.51 2.17 1.84 1.50 1.17 0.84 0.50 0.17 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.30 1.19 2.60 4.57 7.19 10.45 14.34 18.86 24.01 29.80 35.75 41.34 46.58 51.47 56.01 60.21 64.06 67.57 70.73 73.56 76.05 78.21 80.02 81.50 82.64 83.45 83.92 84.06 83.87 83.34 82.65 81.95 81.26 80.57 79.88 79.19 78.51 77.82 77.13 76.45 75.77 75.09 74.41 73.73 73.05 0.00 0.33 1.31 2.86 4.93 7.58 10.86 14.79 19.35 24.54 30.36 36.32 41.93 47.18 52.09 56.65 60.86 64.72 68.23 71.41 74.24 76.74 78.89 80.71 82.19 83.34 84.15 84.62 84.76 84.56 84.03 83.34 82.65 81.95 81.26 80.57 79.88 79.19 78.51 77.82 77.13 76.45 75.77 75.09 74.41 73.73 25 0.00 0.02 0.06 0.13 0.18 0.19 0.21 0.22 0.24 0.27 0.28 0.29 0.29 0.30 0.31 0.32 0.32 0.33 0.33 0.34 0.34 0.34 0.34 0.34 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.34 0.34 0.34 0.34 0.34 0.34 0.34 0.34 0.34 0.34 0.34 0.00 0.00 0.02 0.11 0.21 0.24 0.28 0.32 0.38 0.45 0.48 0.52 0.55 0.58 0.61 0.64 0.67 0.70 0.71 0.72 0.73 0.74 0.75 0.76 0.76 0.77 0.77 0.77 0.77 0.77 0.77 0.77 0.77 0.76 0.76 0.76 0.75 0.75 0.75 0.75 0.74 0.74 0.74 0.74 0.73 0.73 324.80 324.80 324.82 324.91 325.01 325.04 325.08 325.12 325.18 325.25 325.28 325.32 325.35 325.38 325.41 325.44 325.47 325.50 325.51 325.52 325.53 325.54 325.55 325.56 325.56 325.57 325.57 325.57 325.57 325.57 325.57 325.57 325.57 325.56 325.56 325.56 325.55 325.55 325.55 325.55 325.54 325.54 325.54 325.54 325.53 325.53 Inflow/Outflow Simulation 100-Year Storm Event 7.00 ., I ' -' I ' 6 .00 ' I ' I ' I ' I ' 5 .00 I ' -"O ' I c ' 0 0 CJ) I ' I ' (,I) .... 4 .00 CJ) 0... -CJ) CJ) L&.. 0 :0 ;:, 3 .00 (.) -~ 0 s: ;:, 0 2.00 I J~ "' . - I 7. ·-.~ ... I ' . I ' , l r-.... ... I v ...... ' ' -~ ... ' ' ... I ' ' ' ' • ' I ' I ' . , ' I\. ·J , ' \ -~ , \ " \ ' . ,' ' ' I ,' \ ' 1· "~ , " ' , ''" ' , '' ... ~ -~ 1.00 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post -Post-...... -... -Post- Developme Developme Developme Developme nt nt Outflow nt Outflow nt "Free- Hydrograph Hydr ograph Wit h Flow" Without Det enti o n Detention 26 Inflow/Outflow Simulation 2-Year Storm Event 2.50 2.00 ""' "O c 0 0 Q) 1.50 (/) ... Q) a.. -Q) Q) u. 0 :0 :J () -~ 1.00 0 = :J 0 0.50 0 .00 0 5 10 15 20 25 30 35 40 45 Time (Minutes) Pre-Development Hyd ro g raph ----To tal Post-Develo pm ent Hyd rograph 27 Inflow/Outflow Simulation 5-Year Storm Event 0 5 10 15 20 25 30 35 40 45 Time (Minutes) ---Pre-Development Hydrograph ----To t a l Post-Development Hydrograph 28 Inflow/Outflow Simulation 10-Year Storm Event 3 .50 3 .00 2 .50 ....... "O c: 0 0 Cl> (/) .... 2.00 Cl> 0.. -Cl> Cl> LL. 0 :.a :J () 1.50 ......, ~ 0 E :J 0 1.00 0.50 0.00 0 5 10 15 20 25 30 35 40 45 Time (Minutes) Pre -Development Hydr ogra ph ----Tota l Post-Development Hydrograph 29 Inflow/Outflow Simulation 25-Year Storm Event 4 .00 3.50 3.00 ........ "O c 0 2.50 0 Cl> (/) ... Cl> CL. -Cl> Cl> 2.00 u.. 0 :0 ::::J () ........ ~ 0 1.50 ~ ::::J 0 1.00 0 .50 0.00 0 5 10 15 20 25 30 35 40 45 Time (Minutes) ---Pre-Development Hydrograph ----To t a l Post-Development Hydrograph 30 Inflow/Outflow Simulation 50-Year Storm Event ....... 3 .00 "O c: 0 0 Cl> V'> -Cl> 2 .50 Q. -Cl> Cl> u.. 0 :0 2 .00 ::::> u .._, ?; 0 s: ::::> 0 1.50 0 5 10 15 20 25 30 35 40 45 Time (Minutes) Pr e-Development Hydrograph ----To tal Post-Develo pment Hyd rograph 31 Inflow/Outflow Simulation 100-Year Storm Event 4.50 B 3 .00 c 0 0 Q) en .... Q) 2 .50 0.. -Q) Q) LL. 0 :0 2.00 J u -~ 0 E J 0 1.50 J\ I ~\ II ~\ II ' \ 1 ' •\ I \ ' \ ~ \ I 4 .00 3 .50 l.00 0 .50 0 .00 0 5 lO 15 20 25 30 35 40 45 Time (Minutes) Pre-De v el opm ent Hydrograph ---Tota l Po st -Devel o pme nt Hydr o g raph 32 Detention Pond Storage Volumes as Percent of Maximum Volume 100% 90% 80% 70% Q) E :J 0 60% > E :J E ')( 50% 0 ::: 0 -40% c <1> 0 .... <1> 0.. 30% 20% 10% 0% 2-year 5-year 10-year 25-year 50-year 100-year Design Storm Storm Depth Storm Elevatio n 325 .35 325.42 325.47 325 .52 325.56 325 .57 Storm Volume i2i3 ;544 i784 2086 2385 2502 Maximum Capacity 632i 632i 632i 632i 632i 632i Percent of Capacity i9% 24% 28 % 33% 38% 40% 33 DRAINAGE COMPUTATIONS for Detention Pond 11 C 11 -Summit Street Four-Plexes being Lots 1R-4R Of A Replat Of Block 14A Southwood Valley -Section 19 C oll ege Stati on, B razos C ounty , Texas P r epared for Mr. Tony Jones 4475 Hicks Lane College Station, Texas 77845 Prepared bv: Garrett Engineering 4444 Carter Creek Parkway -Suite 108 Bryan, Texas 77802 Telephone: (409) 846-2688 *April, 1995 * Determine Total Pre-Development Peak Sto r m Water Discharge Rates Tributary Area ("A " 0.53 Acres Pervious Area : Impervious Area: 0.52 0.01 Acres Acres Run-Of f Coefficie nt ("Cwt"): 0.41 Time Of Concentration ("T/c"): Wood lan d s: Low Elevation: High Elevation: Distance (Feet): Slope (%Grade): Velocity ("Vw"): Time : Pastu res: Low Elevation : High Elevation : Distance (Feet): S lope (%Grade): Velocity ("Vp"): Time : Pave me nt s: Low Elevation : High Elevation : Distance (Feet): Slope (%Grade): Velocity ("Vpave "): Time : Total Trave l Time : Hourly In tensity Ra t es ("I"): 2-Year : 6.33 5-Year : 7.69 10-Year: 8.63 25-Year: 9.86 50-Year: 11 .15 100-Year: 11 .64 Peak D ischarge Rate ("Q"): 2-Year: 1.38 5-Year: 1.68 10 -Year : 1.88 25-Year: 2.15 50-Year: 2.43 100-Year : 2.54 c = 0.4 0 C= 0.98 0.00 0.00 0.00 0.00 0.00 Feet I Second 0.00 Minutes 0.00 0.00 0.00 0.00 0.00 Feet I Second 0.00 Minutes 0.00 0.00 0.00 0.00 0.00 Feet I Second 0.00 Minutes 10.00 Minutes Inches I Hour Inches I Hour Inches I Hou r Inches I Hour Inches I Hour Inc hes I Hour Cubic Feet I Second Cubic Feet I Second C ubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Determine Post-development Peak Storm Water Dischar e No Detention Tributary Area ("A " 0.53 Acres Pervious Ar ea : Impervious Area : Run-Off C oefficient ("Cwt"): 0.63 0.32 0.21 Acres Acres C= 0.40 C= 0.98 Time Of Concentration ("Tic 1 O Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 5-Year: 10-Year: 25-Year: 50-Year: 100-Year: Peak Discharge Rate ("O "): 2-Year: 5-Year: 10-Year: 25-Year: 50-Year : 100-Year : 6.33 Inches I Hour 7.69 Inc hes I Hour 8.63 Inches I Hour 9.86 Inches I Hour 11.15 Inc hes I Hour 11 .64 Inches I Hour 2.11 Cub ic Feet I Second 2.57 Cubic Feet I Second 2.88 Cub ic Feet I Second 3 .29 Cubic Feet I Second 3 .72 Cub ic Feet I Seco nd 3 .89 Cubic Feet I Second Comparison Of Predevelopment And Post-development Peak Discharge Rates Predeve lopmer Post -De v elopment Increase 2-Year: 1 .38 Ft3/sec 2.11 Ft3 /sec 0.73 Ft3 /sec 5-Year: 1.68 Ft3 /sec 2.57 Ft3/sec 0.89 Ft3/sec 10-Yea r: 1.88 Ft3/sec 2.88 Ft3/sec 1.00 Ft3/sec 25-Year: 2.15 Ft3 /sec 3.29 Ft3/sec 1 .14 Ft3 /sec 50-Year: 2.43 Ft3 /sec 3.72 Ft3/sec 1 .29 Ft3/sec 100-Year: 2 .54 Ft3/sec 3.89 Ft3/sec 1 .35 Ft3/sec Preliminary Determination Of Detention Pond Volume 2-Yea r: 0.73 Ft 3/sec : (3 0 Min . x 60 Sec . I 2 ) = 66 0 Cubic 5-Yea r: 0.89 Ft3/sec : (30 Min . x 60 Sec. I 2 ) = 803 Cubic 10-Year: 1.00 Ft3/sec : (30 Min. x 60 Sec. I 2 ) = 901 Cubic 25-Yea r: 1.14 Ft 3/sec : (30 Min . x 60 Sec . I 2 ) = 1,030 Cubic 50-Year: 1.29 Ft3/sec : (30 Min . x 60 Sec . I 2 ) = 1,164 Cubic 00-Yea r: 1 .35 Ft3/sec : (30 Min. x 60 Sec. I 2 ) = 1,215 Cubic 2 Feet Feet Feet Feet Feet Feet Determine Post-Development "Fr ee-Flow " Pe a k Storm Water Discharge Tributa ry Area ("A " 0.24 Acres Pervious Area : Impervious Area : Run-Off Coefficient ("Cwt"): 0.69 0.12 0.12 Acres Acres Time Of Concentration ("Tic 10 Minutes (Min) Hourly Intensity Rates ("I "): 2-Year: 5-Year: 10-Year: 25-Year: 50-Year : 100-Year: Peak Discharge Rate ("O"): 2-Year: 5-Year: 10-Year: 25 -Year : 50-Year: 100-Year: 3 6.33 7.69 8.63 9.86 11.15 11 .64 1.05 1.27 1.43 1.63 1.85 1.93 c = 0.40 C= 0.98 Inches I Hour Inches I Hour Inches I Hour Inc hes I Hou r Inc hes I Hour Inches I Hour Cubic Feet I Second Cub ic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Determine Post-Development Flow Into Detention Pond Tributary Area ("A " 0.29 Acres Pervious Area : Impervious Area : Run-Off Coefficient ("Cwt"): 0.58 0.20 0.09 Acres Acres Time Of Concentration ("Tic 1 O Minutes (Min) Hourly Intensity Rates ("I"): 2-Year: 5-Year : 10 -Year : 25-Year : 50-Year : 100-Year: Peak Discharge Rate ("Q"): 2-Year: 5-Year: 10-Year: 25-Year: 50-Year : 100-Year: 4 6.33 7.69 8.63 9.86 11 .15 11.64 1.06 1.29 1.45 1.66 1.88 1.96 c = 0.40 C= 0.98 Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Inches I Hour Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Cubic Feet I Second Pre-Deve lopment Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year {Minutes} Storm Storm Storm Storm Storm Storm 0 0 .00 0.00 0.00 0.00 0 .00 0.00 1 0.14 0.17 0 .19 0.21 0 .24 0 .25 2 0 .28 0.34 0.38 0.43 0.49 0 .51 3 0.41 0 .50 0.56 0.64 0.73 0 .76 4 0 .55 0.67 0.75 0.86 0 .97 1.01 5 0 .69 0 .84 0.94 1.07 1.21 1.27 6 0 .83 1.01 1.13 1.29 1.46 1.52 7 0 .96 1.17 1.32 1 .50 1 .70 1 .77 8 1 .10 1.34 1 .50 1 .72 1 .94 2.03 9 1 .24 1 .51 1.69 1.93 2 .19 2 .28 Peak=> 10 1 .38 1.68 1.88 2.15 2.43 2.54 11 1.31 1.59 1 .79 2.04 2 .31 2.41 12 1.24 1 .51 1.69 1.93 2 .19 2 .28 13 1.17 1.42 1.60 1.83 2.06 2.15 14 1.10 1.34 1.50 1.72 1 .94 2 .03 15 1 .03 1 .26 1.41 1 .61 1 .82 1.90 16 0.96 1.17 1.32 1 .50 1 .70 1 .77 17 0.90 1.09 1.22 1.40 1.58 1.65 18 0 .83 1.01 1.13 1.29 1.46 1.52 19 0 .76 0 .92 1.03 1 .18 1.34 1 .39 20 0 .69 0 .84 0 .94 1.07 1 .21 1.27 21 0 .62 0.75 0 .85 0 .97 1.09 1.14 22 0 .55 0 .67 0 .75 0.86 0 .97 1.01 23 0.48 0 .59 0 .66 0.75 0 .85 0 .89 24 0.41 0 .50 0 .56 0.64 0 .73 0.76 25 0 .34 0.42 0.47 0.54 0.61 0.63 26 0 .28 0 .34 0.38 0.43 0.49 0.51 27 0.21 0 .25 0.28 0 .32 0 .36 0.38 28 0 .14 0.17 0 .19 0.21 0 .24 0 .25 29 0.07 0 .08 0 .09 0 .11 0 .12 0 .13 30 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 5 Post-Development Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Y ear 1 00-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.21 0.26 0.29 0.33 0.37 0.39 2 0.42 0.51 0.58 0.66 0.74 0.78 3 0.63 0.77 0.86 0.99 1.12 1.17 4 0.84 1.03 1.15 1.32 1.49 1.55 5 1.06 1.28 1.44 1.65 1.86 1.94 6 1.27 1.54 1.73 1.98 2.23 2.33 7 1.48 1.80 2.02 2.30 2.60 2.72 8 1.69 2.05 2.31 2.63 2.98 3.11 9 1.90 2.31 2.59 2.96 3.35 3.50 Peak=> r1o -~ .. ,,,... ... ,. ------3.29 2.11 2.$7 ~ 2.88 3.72 3.89 11 2.01 2.44 2.74 3.13 3.54 3.69 12 1.90 2.31 2.59 2.96 3.35 3.50 13 1.80 2.18 2.45 2.80 3.16 3.30 14 1.69 2.05 2.31 2.63 2.98 3.11 15 1.58 1.93 2.16 2.47 2.79 2.91 16 1.48 1.80 2.02 2.30 2.60 2.72 17 1.37 1.67 1.87 2.14 2.42 2.53 18 1.27 1.54 1.73 1.98 2.23 2.33 19 1.16 1.41 1.59 1.81 2.05 2.14 20 1.06 1.28 1.44 1.65 1.86 1.94 21 0.95 1.16 1.30 1.48 1.67 1.75 22 0.84 1.03 1.15 1.32 1.49 1.55 23 0.74 0.90 1.01 1.15 1.30 1.36 24 0.63 0.77 0.86 0.99 1.12 1.17 25 0.53 0.64 0.72 0.82 0.93 0.97 26 0.42 0.51 0.58 0.66 0.74 0.78 27 0.32 0.39 0.43 0.49 0.56 0.58 28 0.21 0.26 0.29 0.33 0.37 0.39 29 0.11 0.13 0.14 0.16 0.19 0.19 30 0.00 0.00 0.00 0.00 0.00 0.00 6 Post-Development "Free-Flow" Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.10 0.13 0.14 0.16 0.18 0.19 2 0.21 0.25 0.29 0.33 0.37 0.39 3 0.31 0.38 0.43 0.49 0.55 0.58 4 0.42 0.51 0.57 0.65 0.74 0.77 5 0.52 0.64 0.71 0.82 0.92 0.96 6 0.63 0.76 0.86 0.98 1.11 1.16 7 0.73 0.89 1.00 1.14 1.29 1.35 8 0.84 1.02 1.14 1.31 1.48 1.54 9 0.94 1.15 1.29 1.47 1.66 1.73 Peak=> C10 -~--_l . .Q5_ 1.27 1.~--1.63 1.85 1.93 -11 1.00 1.21 1.36 1.55 1.75 1.83 12 0.94 1.15 1.29 1.47 1.66 1.73 13 0.89 1.08 1.22 1.39 1.57 1.64 14 0.84 1.02 -1.14 1.31 1.48 1.54 15 0.79 0.96 1.07 1.22 1.38 1.45 16 0.73 0.89 1.00 1.14 1.29 1.35 17 0.68 0.83 0.93 1.06 1.20 1.25 18 0.63 0.76 0.86 0.98 1.11 1.16 19 0.58 0.70 0.79 0.90 1.02 1.06 20 0.52 0.64 0.71 0.82 0.92 0.96 21 0.47 0.57 0.64 0.73 0.83 0.87 22 0.42 0.51 0.57 0.65 0.74 0.77 23 0.37 0.45 0.50 0.57 0.65 0.67 24 0.31 0.38 0.43 0.49 0.55 0.58 25 0.26 0.32 0.36 0.41 0.46 0.48 26 0.21 0.25 0.29 0.33 0.37 0.39 27 0.16 0.19 0.21 0.24 0.28 0.29 28 0.10 0.13 0.14 0.16 0.18 0.19 29 0.05 0.06 0.07 0.08 0.09 0.10 30 0.00 0.00 0.00 0.00 0.00 0.00 7 Post-Development Flow Routed Through Detention Pond Inflow Hydrograph Ordinates (Cubic Feet per Second) Time 2-Year 5-Year 10-Year 25-Year 50-Y ear 100-Year (Minutes) Storm Storm Storm Storm Storm Storm 0 0.00 0.00 0.00 0.00 0.00 0.00 1 0.11 0.13 0.15 0.17 0.19 0.20 2 0.21 0.26 0.29 0.33 0.38 0.39 3 0.32 0.39 0.44 0.50 0.56 0.59 4 0.43 0.52 0.58 0.66 0.75 0.78 5 0.53 0.65 0.73 0.83 0.94 0.98 6 0.64 0.78 0.87 1.00 1.13 1.17 7 0.74 0.91 1.02 1.16 1.31 1.37 8 0.85 1.04 1.16 1.33 1.50 1.57 9 0.96 1.16 1.31 1.49 1.69 1.76 Peak=> I ---· {45' -·1.66 -10 1.06 1.29 1.88 1.96 -----· 11 1.01 1.23 1.38 1.58 1.78 1.86 12 0.96 1.16 1.31 1.49 1.69 1.76 13 0.90 1.10 1.23 1.41 1.59 1.66 14 0.85 1.04 1.16 1.33 1.50 1.57 15 0.80 0.97 1.09 1.24 1.41 1.47 16 0.74 0.91 1.02 1.16 1.31 1.37 17 0.69 0.84 0.94 1.08 1.22 1.27 18 0.64 0.78 0.87 1.00 1.13 1.17 19 0.59 0.71 0.80 0.91 1.03 1.08 20 0.53 0.65 0.73 0.83 0.94 0.98 21 0.48 0.58 0.65 0.75 0.84 0.88 22 0.43 0.52 0.58 0.66 0.75 0.78 23 0.37 0.45 0.51 0.58 0.66 0.69 24 0.32 0.39 0.44 0.50 0.56 0.59 25 0.27 0.32 0.36 0.41 0.47 0.49 26 0.21 0.26 0.29 0.33 0.38 0.39 27 0.16 0.19 0.22 0.25 0.28 0.29 28 0.11 0.13 0.15 0.17 0.19 0.20 29 0.05 0.06 0.07 0.08 0.09 0.10 30 0.00 0.00 0.00 0.00 0.00 0.00 8 2.50 .... Cl> ICI.. -2 .00 Cl> Cl> LL. 0 ........ 1.50 ·-"O .c c ::::> 0 u 0 ......, Cl> l.00 Cl> C/) 0) .... 0 .t:. 0.50 0 "' i5 0.00 0 3.00 -Cl> Cl> 2.50 LL. 0 ........ ·-"O 2.00 .c c ::::> 0 u 0 1.50 ......, Cl> Cl> C/) 0) .... l.00 .... Cl> 0 ICI.. .t:. 0 0 .50 "' i5 0.00 0 Total Pre-Development Vs. Total Post-Developmen t (No Detention) Peak Discharge Rates 2-Year Storm Event 5 10 15 20 25 Ti me (Min utes) Pre -Development Hydrograph ----Total Post-De ve lopment Hydrograph Total Pre -Development Vs . Total Post-Development (No Detention) Peak Discharge Rates 5-Year Storm Event 5 10 15 20 25 Time (M in utes ) Pr e-Development Hydrograph ----Post -Development Outflow Hydrograph Without Detention 9 30 30 Q; Cl.. "$ Q) Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 10-Year Storm Event ~ " 2.00 -----+---#~--+-----+------+-----+-------< :0 -g 8 8 1.50 +-----¥-----7"'---t---"""""-:::t-------3...t-----+------4 -Q) Q) (I) Ol 1.00 +------..~-j,.L-----+-----+---~d----.31ooo.,---+------l 5 .t: 0 I/) 0 ... 0.00 -f'----+----+----4-----+----+----'"111 0 5 10 15 20 25 Time (Minutes) Pr e-Dev e lopment Hydrograph ----Po st-Deve lo p ment Outflow Hydrograph Without Detent ion Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 25-Year Storm Event 30 Q) a.. 3.oo..-----+----1--+-__....------+-----+-----+------j "$ ~ 2.501-----+--+---+--------'-.C------+-----+----~ 0,.... :0 -g 2.00 1-----+-:,__--T-+-"""-<::,.-------+--~.----+-----+----~ :::J 0 u 0 -Q) 1.50 +---~+--r---t--------J~c------+~---+----j Q) (/) Ol 5 1.00 -t---F-----7'!----t--------J------f""""-::--""~----j .t: 0 cS 0 .50 ...-~,,c---;----+-----t-----+----~~......---1 0.00 .---~I'-----+---..... ---.... ---.._--...... 0 5 10 15 20 25 Time (Minutes) ---Pre-D evelopment Hydrograph ----Post-D evelo pme nt O utflow Hydro graph Wi t h o ut Detent ion 10 30 -Q) Q) LI.. Total Pre-Development Vs . Total Post-Development (No Detention) Peak Discharge Rates 50-Year Storm Event l.00 +---l-~+----+-------1-----1--=-.c-------"...,_------1 0 .50 +-#-7"-'----11------+-----+-----+-----~~.,---------i 0 .00 -I'-----+----+----+----+----+---~ 0 5 10 15 20 25 Time (Minutes) ---Pre-Development Hydrograph ----Post-Development Outflow Hydrograph Without Detention 4 .00 3.50 Total Pre-Development Vs. Total Post-Development (No Detention) Peak Discharge Rates 100-Year Storm Event 30 3.00 0,,.... ·-"O ..0 c :J 0 () 0 ....., Q) Q) <I) O> ... ... Q) 0 Q.. .&:. 0 II) i5 2.50 2 .00 l.50 l.00 0 .50 0.00 0 5 10 15 20 25 Time (Minutes) ---Pre-Development Hydrograph ----Post-Develo pment Outflow Hydrograph Without Detention 11 30 Detention Pond De th Vs. Volume i Q) u.. 1.20 1.00 0.80 ~ 0.60 a. Q) a 0.20 0.00 Ele vation 324 .50 324 .75 325.00 325.25 325 .50 325 .67 Depth Volume (Feet) (Ft3) 0.00 0 0.25 176 0 .50 635 0 .75 1,735 1.00 3 ,327 1.17 4 ,634 Detention Pond Depth Vs. Volume 0 1,000 2,000 3 ,000 4 ,000 Detention Po n d Volume (Cubic Fe e t) 12 5,000 Rating Curve For Outlet Control Structure Pipe Dia. (Inches): 4 0 .33 De th Vs. Volume Pi pe Length 12 .00 Feet El evation Depth Discha rg e (Feet) Ft3/Sec 324 .50 0.00 0.00 324 .75 0 .25 0.20 325 .00 0.50 0 .28 325 .25 0 .75 0 .34 32 5.50 1.00 0.40 325 .67 1.17 0.43 Rating Curve For Outlet Control Structure Depth Vs. Volume ~ Cl> LL. ~ 0 .60 -------t---t-------t---t-------t----+1------1r-----+------i a. Cl> 0 0 .20 0.00 0 .00 0 .05 0.10 0 . 15 0 .20 0.25 0 .30 0 .35 0 .4 0 0 .45 Dis charg e (Cubic Feet Pe r Second) 13 I Storage Ind ication Curve Depth Storage Discharge 2s/t 2s/t+O (Feet) (Ft3) (Ft3/Sec) (Ft3/Sec) (Ft3/Sec) 0 .00 0 0 .00 0.0 0 0.0 0 0 .25 176 0 .20 5 .87 6.06 0.50 635 0.28 21 .17 21.45 0 .75 1 ,735 0 .34 57 .83 58.18 1.00 3,327 0.40 110.90 11 1.3 0 1.17 4,634 0.43 154.47 154.90 Storage Indication Curve 0 .45 0 .35 ,....,, "O c 0 0 .3 0 0 ~ ... ~ ~ / ~ ~ v """'" ~ ~ 0.40 Q) ll.. -0 .25 Q) Q) LI.. 0 :a 8 0 .20 J I ...... Q) 0) ... 0 .s::. 0 .15 0 VI Ci 0 .10 0 .05 0 .00 0 .00 20.00 40 .00 60 .00 80.00 100.00 120.00 140.00 160 .00 2s /t +O (Cubic Feet Per Second) 14 Inflow I Outflow Simulation 2-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation (Minutes; (Ft3/Sec) (Ft3/Sec) (Feet) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0.11 0.21 0.32 0.43 0.53 0.64 0.74 0.85 0.96 1.06 1.01 0.96 0.90 0.85 0.80 0.74 0.69 0.64 0.59 0.53 0.48 0.43 0.37 0.32 0.27 0.21 0.16 0.11 0.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.11 0.10 0.32 0.39 0.53 0.86 0.74 1.50 0.96 2.30 1.17 3.24 1.38 4.33 1.60 5.53 1.81 6.93 2.02 8.53 2.08 10.16 1.97 11.67 1.86 13.05 1.76 14.32 1.65 15.47 1.54 16.50 1.44 17.41 1.33 18.21 1.22 18.90 1.12 19.47 1.01 19.93 0.90 20.28 0.80 20.52 0.69 20.66 0.59 20.68 0.48 20.61 0.37 20.42 0.27 20.14 0.16 19.75 0.05 19.26 0.00 18.72 0.00 18.19 0.00 17.67 0.00 17.15 0.00 16.63 0.00 16.12 0.00 15.62 0.00 15.12 0.00 14.63 0.00 14.14 0.00 13.66 0.00 13.18 0.00 12.71 0.00 12.24 0.00 11.78 0.00 0.11 0.42 0.92 1.61 2.46 3.47 4.63 5.92 7.34 8.96 10.60 12.13 13.53 14.81 15.97 17.01 17.93 18.74 19.43 20.01 20.48 20.83 21.08 21.21 21.24 21.16 20.98 20.69 20.30 19.80 19.26 18.72 18.19 17.67 17.15 16.63 16.12 15.62 15.12 14.63 14.14 13.66 13.18 12.71 12.24 15 0.00 0.00 0.01 0.03 0.05 0.08 0.11 0.15 0.19 0.20 0.21 0.22 0.23 0.24 0.24 0.25 0.26 0.26 0.27 0.27 0.27 0.27 0.28 0.28 0.28 0.28 0.28 0.28 0.28 0.27 0.27 0.27 0.27 0.26 0.26 0.26 0.25 0.25 0.25 0.25 0.24 0.24 0.24 0.24 0.23 0.23 0.00 324.50 0.00 324.50 0.00 324.50 0.01 324.51 0.02 324.52 0.04 324.54 0.08 324.58 0.15 324.65 0.24 324.74 0.27 324.77 0.29 324.79 0.31 324.81 0.34 324.84 0.36 324.86 0.38 324.88 0.40 324.90 0.42 324.92 0.44 324.94 0.45 324.95 0.46 324.96 0.47 324.97 0.48 324.98 0.49 324.99 0.49 324.99 0.50 325.00 0.50 325.00 0.49 324.99 0.49 324.99 0.49 324.99 0.48 324.98 0.47 324.97 0.46 324.96 0.45 324.95 0.44 324.94 0.43 324.93 0.42 324.92 0.41 324.91 0.40 324.90 0.40 324.90 0.39 324.89 0.38 324.88 0.37 324.87 0.36 324.86 0.36 324.86 0.35 324.85 0.34 324.84 Inflow/Outflow Simulation 2-Year Storm Event 2.50 I ' 2.00 I ' ' I ' I ' ..... "O I ' c 0 I ' 0 I Cl> ' (/) 1.50 I .... I Cl> ' Q.. I ... .... Cl> I ' Cl> • ~ 0 I ' :0 .. I ::::J () l.00 -~ I 0 ' E I ' ' / ' ::::J I ' ' 0 I ' ' I ' ' ' I I ' ' ' I ' ' ' ' 0.50 ' ' 0.00 0 5 10 15 20 25 30 Time (Minutes) Pre---. . Post -Post-- - - - -· Post- Developm Devel opm Developm Developm ent ent ent ent "Free- Hydrograp Outflow Outflow Flow· h Hydrograp Wit h h Wit hout De t ention Detention 16 Inflow I Outflow Simulation 5-Year Storm Event Time Inflow 11 + 12 2s/t-0 2s/t+O Outflow Depth Elevation (Minutes; (Ft3/Sec) ___________________ Ci:t~/Sec) (Feet) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0.13 0.26 0.39 0.52 0.65 0.78 0.91 1.04 1.16 1.29 1.23 1.16 1.10 1.04 0.97 0.91 0.84 0.78 0.71 0.65 0.58 0.52 0.45 0.39 0.32 0.26 0.19 0.13 0.06 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.13 0.12 0.39 0.48 0.65 1.05 0.91 1.83 1.16 2.80 1.42 3.94 1.68 5.26 1.94 6.79 2.20 8.56 2.46 10.57 2.52 12.63 2.39 14.53 2.26 16.28 2.13 17.89 2.01 19.35 1.88 20.67 1.75 21.85 1.62 22.90 1.49 23.82 1.36 24.61 1.23 25.26 1.10 25.78 0.97 26.18 0.84 26.44 0.71 26.57 0.58 26.57 0.45 26.45 0.32 26.19 0.19 25.81 0.06 25.30 0.00 24.72 0.00 24.15 0.00 23.58 0.00 23.02 0.00 22.45 0.00 21.89 0.00 21.33 0.00 20.77 0.00 20.21 0.00 19.67 0.00 19.13 0.00 18.59 0.00 18.06 0.00 17.54 0.00 17.02 0.00 0.13 0.51 1.12 1.96 2.99 4.22 5.63 7.20 8.99 11.02 13.10 15.02 16.79 18.42 19.89 21.23 22.42 23.47 24.39 25.18 25.84 26.36 26.75 27.02 27.15 27.15 27.03 26.77 26.39 25.87 25.30 24.72 24.15 23.58 23.02 22.45 21.89 21.33 20.77 20.21 19.67 19.13 18.59 18.06 17.54 17 0.00 0.00 0.02 0.04 0.06 0.10 0.14 0.18 0.20 0.21 0.22 0.24 0.25 0.26 0.26 0.27 0.28 0.28 0.28 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.29 0.28 0.28 0.28 0.28 0.28 0.28 0.28 0.27 0.27 0.27 0.26 0.26 0.26 0.00 324.50 0.00 324.50 0.00 324.50 0.01 324.51 0.03 324.53 0.06 324.56 0.12 324.62 0.22 324.72 0.27 324.77 0.29 324.79 0.32 324.82 0.35 324.85 0.39 324.89 0.42 324.92 0.44 324.94 0.47 324.97 0.50 325.00 0.51 325.01 0.51 325.01 0.52 325.02 0.52 325.02 0.53 325.03 0.53 325.03 0.53 325.03 0.53 325.03 0.54 325.04 0.54 325.04 0.53 325.03 0.53 325.03 0.53 325.03 0.53 325.03 0.52 325.02 0.52 325.02 0.52 325.02 0.51 325.01 0.51 325.01 0.51 325.01 0.50 325.00 0.50 325.00 0.49 324.99 0.48 324.98 0.47 324.97 0.46 324.96 0.45 324.95 0.44 324.94 0.43 324.93 3 .00 2.50 ,, 5 2.00 0 G> (f) ... G> n.. Q; G> LL. 1.50 0 :0 :J ~ 3:: 0 s: :J 1.00 0 0.50 0.00 0 Inflow/Outflow Simulation 5-Year Storm Event ,, I I I I I I 5 Pre----- Deve lopm ent Hydrograp h I ' I 10 ' "' ' ' ... ' ' 15 Time (Minutes) Post- Developm ent Outflow Hydrograp h Without Detention 18 20 25 Post ----·---- Developm ent Outflow Wi t h Detention 30 Post- Developm ent "Free- Flow" Inflow I Outflow Simulation 10-Year Storm Event T ime Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation (Ft3/Sec) (Feet) (Minutes; (Ft3/Sec) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0 .00 0 .15 0 .29 0 .44 0 .58 0 .73 0 .87 1 .02 1 .16 1.31 1.45 1.38 1.31 1 .23 1.16 1.09 1.02 0 .94 0.87 0 .80 0 .73 0 .65 0 .58 0 .51 0.44 0 .36 0 .29 0 .22 0 .15 0 .07 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0.15 0 .14 0.44 0.53 0 .73 1.18 1.02 2 .05 1.31 3 .14 1.60 4.43 1.89 5 .92 2.18 7.68 2.47 9 .71 2 .76 12 .00 2 .83 14.34 2 .69 16.52 2.54 18.53 2.40 20 .37 2 .25 22 .05 2 .11 23 .59 1.96 24 .98 1.82 26.21 1.67 27 .30 1.52 28 .24 1.38 29 .03 1.23 29 .68 1.09 30 .17 0 .94 30.53 0 .80 30 .73 0 .65 30.79 0 .51 30.70 0 .36 30.47 0 .22 30.10 0 .07 29 .58 0 .00 28.99 0 .00 28.41 0.00 27 .82 0.00 27 .24 0 .00 26.66 0.00 26 .09 0.00 25 .51 0 .00 24 .94 0 .00 24 .36 0 .00 23.79 0 .00 23 .22 0 .00 22.66 0 .00 22 .09 0 .00 21 .53 0 .00 20 .97 0.00 0.15 0 .57 1.26 2 .19 3.36 4.74 6 .32 8 .10 10.15 12.47 14.83 17.03 19 .06 20.92 22 .62 24 .16 25 .55 26 .79 27.88 28 .83 29 .62 30.27 30.77 31 .12 31 .32 31.38 31 .30 31 .07 30 .69 30 .17 29 .58 28 .99 28.41 27.82 27.24 26 .66 26 .09 25 .51 24 .94 24 .36 23 .79 23 .22 22 .66 22 .09 21.53 19 0.00 0.00 0.02 0.04 0 .07 0 .11 0.15 0 .20 0 .21 0 .22 0 .23 0 .24 0 .26 0 .27 0 .28 0 .28 0 .28 0.29 0 .29 0 .29 0 .29 0 .29 0 .30 0 .30 0 .30 0 .30 0.30 0 .30 0 .30 0 .30 0 .29 0 .29 0 .29 0 .29 0 .29 0.29 0.29 0 .29 0 .29 0 .29 0 .29 0 .28 0 .28 0.28 0.28 0.28 0 .00 324 .50 0 .00 324 .50 0 .00 324 .50 0 .01 324 .51 0 .03 324 .53 0 .08 324.58 0.15 324 .65 0 .25 324.75 0.28 324.78 0.31 324 .81 0.34 324 .84 0 .38 324 .88 0.42 324 .92 0.46 324 .96 0.49 324 .99 0.51 325 .01 0 .52 325 .02 0.53 325 .03 0 .53 325 .03 0 .54 325 .04 0 .55 325 .05 0 .55 325.05 0.56 325 .06 0 .56 325 .06 0.56 325 .06 0.56 325 .06 0.56 325 .06 0 .56 325 .06 0.56 325 .06 0.56 325 .06 0 .55 325 .05 0.55 325 .05 0.55 325 .05 0.54 325 .04 0 .54 325 .04 0 .54 325 .04 0.53 325.03 0 .53 325.03 0 .53 325 .03 0.52 325.02 0 .52 325 .02 0 .51 325 .01 0.51 325 .01 0 .51 325.01 0 .50 325.00 0 .50 325 .00 3 .00 2 .50 13' g 2 .00 0 C1> (/) Q; 0... -C1> C1> LL. 1.50 0 :0 ::J u -~ 0 ~ 1.00 0 0 .50 0 .00 0 Inflow/Outflow Simulation 10-Year Storm Event 5 Pre-. . Develo p m e nt Hydrogra ph I I I I . I • . I I I ' I ' .. ' ' ' ' 10 15 20 25 30 Time (Minutes) Post-Post-. ..... -. Post - Develop Develo p Develo p ment ment m e nt Outflow Outflow "Free- Hydrogra With Flow" ph Detention Without Detentio n 20 Inflow I Outflow Simulation 25-Year Storm Event Time Inflow 11+ 12 2s/t-0 2s/t+O Outflow Depth Elevation (Ft3/Sec) (Feet) (Minutes; (Ft3 /Sec) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0.17 0.33 0.50 0.66 0.83 1.00 1.16 1.33 1.49 1.66 1.58 1.49 1.41 1.33 1.24 1.16 1.08 1.00 0 .91 0 .83 0.75 0.66 0.58 0.50 0.41 0.33 0.25 0.17 0.08 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.17 0.16 0.50 0.61 0.83 1.35 1.16 2.34 1.49 3 .59 1.82 5.06 2.16 6.80 2.49 8.86 2.82 11 .23 3.15 13.89 3.23 16 .61 3.07 19 .14 2.90 21.48 2.74 23 .65 2 .57 25 .64 2.41 27.47 2.24 29 .12 2.07 30 .60 1.91 31.91 1.74 33 .05 1.58 34.02 1.41 34 .82 1.24 35.45 1.08 35 .92 0.91 36 .22 0.75 36 .35 0.58 36.32 0.41 36 .12 0.25 35 .76 0.08 35.23 0.00 34.62 0.00 34 .02 0.00 33.42 0.00 32 .81 0.00 32.22 0.00 31.62 0.00 31 .02 0.00 30.43 0.00 29 .84 0.00 29 .25 0.00 28 .66 0.00 28 .08 0 .00 27 .50 0 .00 26 .92 0.00 26 .34 0.00 0.17 0.65 1.44 2 .51 3 .84 5.41 7.21 9.29 11 .68 14 .38 17 .13 19 .68 22 .04 24 .22 26 .22 28 .05 29 .70 31 .19 32.50 33 .65 34 .62 35.43 36 .06 36 .53 36 .83 36 .96 36 .93 36 .73 36 .37 35 .84 35 .23 34 .62 34 .02 33.42 32 .81 32 .22 31 .62 31 .02 30.43 29 .84 29 .25 28 .66 28 .08 27 .50 26.92 21 0.00 0.01 0.02 0.05 0.08 0.13 0 .18 0.20 0.22 0.23 0.24 0.26 0.27 0.28 0.28 0.29 0.29 0.29 0.30 0.30 0.30 0.30 0.30 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.29 0.29 0.29 0.29 0.29 0.29 0.00 324.50 0.00 324.50 0.00 324 .50 0.01 324.51 0.04 324 .54 0.10 324 .60 0.20 324 .70 0.27 324.77 0.30 324.80 0.33 324 .83 0.37 324 .87 0.42 324.92 0.47 324 .97 0.50 325 .00 0.52 325.02 0.53 325.03 0.54 325 .04 0.55 325 .05 0.56 325 .06 0.57 325 .07 0.58 325 .08 0.58 325.08 0.59 325 .09 0.59 325.09 0.60 325 .10 0.60 325 .10 0.60 325 .10 0.60 325 .10 0.60 325 .10 0.60 325 .10 0.59 325 .09 0.59 325 .09 0.58 325 .08 0.58 325 .08 0.58 325 .08 0.57 325 .07 0.57 325 .07 0.56 325 .06 0.56 325 .06 0.56 325 .06 0.55 325 .05 0.55 325 .05 0.55 325 .05 0.54 325 .04 0.54 325 .04 0.53 325.03 s c 0 0 Cl> V) 3 .50 3 .00 2 .50 £ 2 .00 -Cl> Cl> u.. 0 :.a 8 1.50 ......, ~ 0 = :::> 0 1.00 0 .50 0.00 0 Inflow/Outflow Simulation 25-Year Storm Event 5 Pre-. Developm ent Hydrograp h . I I I I . I I I I . I ' I 10 " " ' " " " " 15 Time (Minutes) Post - Developm ent Outflow Hydrograp h Without Detention 22 20 25 30 Post-. ....... Post- Developm Developm ent ent "Free- Outflow Flow· With Detention Inflow I Outflow Simulation 50-Year Storm Event Time Inflow 11 + 12 2s/t-0 2s/t+O Outflow Depth Elevation (Ft3/Sec) (Feet) (Minutes; (Ft3/Sec) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0.00 0.19 0.38 0.56 0.75 0.94 1.13 1.31 1.50 1.69 1.88 1.78 1.69 1.59 1.50 1.41 1.31 1.22 1.13 1.03 0.94 0.84 0.75 0.66 0.56 0.47 0.38 0 .28 0 .19 0.09 0 .00 0 .00 0 .00 0 .00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.19 0.18 0.56 0.69 0.94 1.52 1.31 2.65 1.69 4 .05 2.06 5.72 2.44 7.74 2.81 10.11 3.19 12 .82 3.56 15 .88 3.66 18 .99 3.47 21 .90 3 .28 24 .61 3 .09 27 .12 2.91 29.44 2 .72 31 .56 2 .53 33.49 2.34 35 .22 2.16 36 .76 1.97 38 .11 1.78 39.27 1.59 40 .24 1.41 41.01 1.22 41 .60 1.03 42.00 0.84 42 .21 0.66 42 .23 0.47 42 .07 0.28 41 .72 0.09 41 .18 0.00 40 .56 0.00 39 .93 0.00 39 .31 0.00 38.68 0.00 38.07 0.00 37.45 0.00 36 .83 0.00 36.22 0.00 35.61 0.00 35.00 0.00 34.39 0.00 33 .79 0.00 33.19 0.00 32 .59 0 .00 31 .99 0.00 0.19 0.74 1.63 2.83 4.34 6.12 8.16 10.55 13 .29 16.38 19 .53 22.46 25 .18 27 .70 30 .03 32 .16 34 .09 35 .83 37.38 38 .73 39.89 40.86 41 .64 42 .23 42 .63 42 .84 42.87 42 .70 42.35 41 .81 41 .18 40 .56 39 .93 39 .31 38 .68 38 .07 37.45 36 .83 36 .22 35 .61 35 .00 34 .39 33 .79 33 .19 32 .59 23 0.00 0.01 0.02 0.05 0.09 0.14 0.20 0.21 0.22 0.24 0.25 0.27 0.28 0.29 0.29 0.29 0.30 0.30 0.30 0.31 0.31 0.31 0.31 0.31 0.32 0.32 0.32 0.32 0.32 0.32 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.30 0.30 0.30 0.30 0.30 0.30 0.00 324.50 0.00 324 .50 0.00 324.50 0.02 324 .52 0.05 324.55 0.13 324.63 0.25 324.75 0.28 324.78 0.31 324 .81 0.36 324.86 0.41 324.91 0.46 324.96 0.51 325 .01 0.52 325 .02 0.54 325.04 0.55 325.05 0.57 325 .07 0.58 325 .08 0.59 325 .09 0.60 325.10 0.61 325.11 0.62 325.12 0.63 325 .13 0.63 325 .13 0.64 325 .14 0.64 325 .14 0.64 325 .14 0.64 325 .14 0.64 325.14 0.64 325.14 0.63 325.13 0.63 325.13 0.62 325.12 0.62 325.12 0.62 325 .12 0.61 325 .11 0.61 325 .11 0.60 325 .10 0.60 325 .10 0.59 325 .09 0.59 325 .09 0.59 325 .09 0.58 325 .08 0.58 325 .08 0.57 325.07 0.57 325 .07 Inflow/Outflow Simulation 50-Year Storm Event 4 .00 i. I ... 3 .5 0 I ' I ... I ... I ... ... I 3 .00 ... . ... I ... ....... "O I "' c I ... 0 0 2.50 Cl> I ... I . Cl) .... Cl> CL. -Cl> Cl> 2 .00 LL. 0 :0 ::::J 0 -~ 1.50 0 ~ ::::J 0 1.00 I ~ ' I ... I ' I ... I ' : / ....... " "" ... ~ ... . ' ' ' ' I '' ... . ' // . . ~ - I ' ' ... I ' . ' ' . ' ... . · I . ' ' "' . ' ' .. . ' ' ·!. ' .. ... ~ . ... . . .. I ... ' ' ~ . I ' I .. ',~'-. . . "' __,,,,,, ~ '' ' .. '~' 0 .50 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post-........ Post- Developm Developm Developm Developm ent ent ent ent "Free- Hydrograp Outflow Outflow Flow" h Hydrograp With h Without Detention Detention 24 Inflow I Outflow Simulation 100-Year Storm Event Time Inflow 11+ 12 2s/t-0 2sl t+O Outflow Depth Elevation (Ft3/Sec) (Feet) (Minutes; (Ft3 /Sec) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 0 .00 0 .20 0 .39 0 .59 0.78 0.98 1.17 1.37 1.57 1.76 1.96 1.86 1.76 1.66 1.57 1.47 1 .37 1.27 1.17 1.08 0 .98 0 .88 0 .78 0 .69 0 .59 0.49 0 .39 0 .29 0 .20 0 .10 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .20 0.18 0 .59 0 .72 0.98 1.59 1.37 2 .77 1.76 4 .23 2 .15 5.99 2 .55 8.11 2.94 10.60 3.33 13.44 3.72 16.65 3 .82 19.92 3 .62 22 .97 3.43 25 .82 3 .23 28.46 3.03 30.90 2 .84 33 .14 2 .64 35.17 2.45 37 .01 2.25 38.64 2 .06 40 .07 1.86 41.30 1.66 42 .33 1.47 43 .16 1.27 43 .79 1.08 44 .23 0 .88 44.47 0 .69 44 .51 0.49 44.36 0 .29 44 .01 0 .10 43.47 0.00 42.84 0 .00 42 .20 0.00 41 .57 0.00 40.94 0 .00 40 .32 0.00 39.69 0 .00 39 .07 0 .00 38.45 0 .00 37.83 0 .00 37.22 0.00 36 .60 0.00 35 .99 0 .00 35 .38 0 .00 34 .77 0 .00 34 .17 0.00 0 .20 0 .77 1.70 2 .96 4.53 6 .38 8 .53 11 .04 13.92 17.16 20.47 23.54 26.40 29 .05 31 .50 33 .74 35 .78 37 .62 39 .26 40 .69 41.93 42 .96 43 .79 44.43 44 .87 45 .11 45 .15 45.00 44 .65 44.11 43.47 42 .84 42 .20 41 .57 40.94 40.32 39 .69 39 .07 38.45 37.83 37 .22 36 .60 35 .99 35 .38 34 .77 25 0 .00 0.01 0.03 0 .06 0.10 0 .15 0 .20 0 .21 0.22 0.24 0.26 0 .27 0.28 0.29 0.29 0.30 0.30 0.30 0 .31 0 .31 0.31 0 .32 0 .32 0 .32 0.32 0 .32 0 .32 0 .32 0.32 0.32 0.32 0.32 0.32 0.32 0.31 0.31 0 .31 0.31 0 .31 0.31 0 .31 0 .31 0.31 0 .30 0 .30 0 .30 0 .00 324.50 0 .00 324.50 0 .00 324 .50 0.02 324.52 0 .06 324 .56 0 .14 324.64 0 .25 324.75 0 .28 324.78 0 .32 324 .82 0 .37 324 .87 0.42 324 .92 0.48 324.98 0 .51 325.01 0 .53 325.03 0 .55 325.05 0 .56 325.06 0 .58 325 .08 0.59 325 .09 0 .60 325 .10 0 .61 325 .11 0 .62 325 .12 0.63 325.13 0 .64 325 .14 0 .65 325.15 0.65 325.15 0.65 325 .15 0.66 325.16 0 .66 325 .16 0.65 325.15 0 .65 325 .15 . 0 .65 325 .15 0.64 325 .14 0 .64 325.14 0 .64 325 .14 0.63 325.13 0.63 325.13 0.62 325.12 0 .62 325 .12 0 .61 325.11 0 .61 325 .11 0 .61 325.11 0.60 325 .10 0 .60 325 .10 0 .59 325 .09 0 .59 325 .09 0 .58 325 .08 Inflow/Outflow Simulation 100-Year Storm Event 4 .00 I ' I ' ' I . I ' 3 .50 I ' I ' I ' 3.00 • ' ' I ' "" "O c I ' I ' 0 0 2 .50 Q) (/) ... Q) ~ -Q) Q) 2.00 ..... 0 Li ::I u -~ 1.50 0 E ::I 0 1.00 I ' . I ~ I ' I ' ' I ' I ' / ........ ~ \ '\ ~ I \ ~ ' \ I \ ' \ \ I " ' \ \ . I I/ . \ ""' ' I . \ . \ -I . \ \ . ' .· I . . \ "" . ' ' ' . ' . ' ' . \ .; .. · ···.,~ ' . ' ' I . ' I'\.. \ I ' \ /' "·~ ' . . . . ',, __/ ......... "' . 0 .50 0 .00 0 5 10 15 20 25 30 Time (Minutes) Pre-----Post-Post-·---·---Post- Developm Developm Devel opm Developm ent ent ent ent "Free- Hydrograp Outflow Outflow Flow· h Hydr ograp With h Without Detention Detention 26 ....... "O c 0 0 Q) en .... Q) Q., -Q) Q) u.. 0 :.0 ::J l.00 0.80 ~ 0.60 ~ 0 E ::J 0 0 .20 0 .00 0 Inflow/Outflow Simulation 2-Year Storm Event 5 10 15 20 25 30 35 40 45 Time (Minutes) Pre -Development Hydrograph ----Total Post-Development Hydrograph 27 1.80 1.60 1.40 £i' 1.20 c 0 0 Q) Cl) ... :. 1.00 Qi Q) u.. 0 :0 8 0 .80 -~ 0 E :J 0 0.60 0 .40 0.20 0 .00 Inflow/Outflow Simulation 5-Year Storm Event 1\ Ii ~ if ~ l , \ ~ ~ \\ \ \ \ \ ' \ 0 5 10 15 20 25 30 35 40 45 Time (Minutes) Pre-Development Hydr o graph ---Total Post -Development Hydrograph 28 Inflow/Outflow Simulation 10-Year Storm Event 2.00 1.40 ........ "O c 0 0 Q) 1.20 V> ... Q) 0... -Q) Q) 1.00 ...... 0 :0 ::J u ...., ~ 0.80 0 = ::J 0 0 .60 ,\ Ii \ II ~ y '\ ' \ \~ \\~ \ \\ \ ' \ 1.80 1.60 0 .40 0 .2 0 0 .00 0 5 10 15 20 25 30 35 40 45 Time (Minutes) ---Pre-Development Hydrograph ---Total Post-Development Hydrograph 29 Inflow/Outflow Simulation 25-Year Storm Event 2 .50 2 .00 -"O c 0 0 Cl) 1.50 (/) ... Cl) 0.. -Cl) Cl) u... 0 :.0 :I u ......., ~ 1.00 0 E :I 0 0 .50 0.00 0 5 10 15 20 25 30 35 40 45 Time (Minutes) Pre-Development Hydrograph ----To t a l Post-Development Hydrograph 30 Inflow/Outflow Simulation 50-Year Storm Event 2 .50 2 .00 """" 'U c 0 0 G> 1.50 V) .... G> ll.. -G> G> LL. 0 :0 :J u ......., ~ 1.00 0 E :J 0 0.50 0.00 0 5 10 15 20 25 30 35 40 45 Time (Minutes) Pre-Development Hydrograph ----Total Po st-Development Hydrograph 31 Inflow/Outflow Simulation 100-Year Storm Event 3 .00 2 .50 13' 2 .00 c: 0 0 Cl> en -Cl> 0.. -Cl> Cl> 1.50 LL. 0 :0 ::I u ~ ~ 0 = ::I 0 1.00 0.50 0 .00 0 5 10 15 20 25 30 35 40 45 Time (Minutes) Pr e -Development Hydrograph ----To ta l Post-Development Hyd rograph 32 100% 90% 80% 70% Q) E :J 0 60% > E :J E ")( 50 % 0 ~ 0 -40% c Q) 0 .... Q) ll. 30% 20% 10% 0% Storm Depth Storm Elevation Storm Volume V1ax im um Capacity 1ercent of Capacity Detention Pond Storage Volumes as Percent of Maximum Volume 2- year 2-ear 0.50 325 .00 628 4634 14% 5- y ear 10-25- year year Design Storm Storm Simulation Synopsis 5-ear 10-ear 25-ear 0.54 0.56 0.60 325 .04 325 .06 325 .10 700 911 1073 4634 4634 4634 15 % 20% 23% 33 50- year 50-ear 0.64 325.14 1249 4634 27% 100- year 100-ear 0.66 325 .16 1320 4634 28% Engineering Report For Sanitary Sewer Improvements To Block 14A, Southwood Valley -Section 19 College Station, Brazos County, Texas Prepared For: Tony Jones 4475 Hicks Lane College Station, Texas 77845 Prepared By: GARRETT ENGINEERING CONSUL TING ENGINEERING & LAND SURVEYING 4444 CARTER CREEK PAAtCVo/AV, SURE 10&. BRYAN, TEXAS 77102. (409) 14S-2181 • (489) 141-3094 *March, 1995 * ENGINEERING REPORT to accompany the replat of Block 14A, Southwood Valley -Section 19 College Station, BRAZOS COUNTY, TEXAS Block I4A of Southwood Valley -Section I9 is situated adjacent to Summit Street. between Southwood Drive and Hilltop Drive in Southwood Valley, College Station, Brazos County. Texas. Block I4A consists of 4 lots, established within the bounds of a I .64 acre tract. Additionally, the project is partially surrounded by developed property, but future expansion of the proposed facilities will likely not be necessary. Soils within the area have shown historically to be quite stable. No faults exist within the project area. and no stability problems are foreseen, other than those caused by the expansive clays typical of Brazos County. Sanitary sewer needs are met by two separate 6" diameter P.V.C. SDR. 26-3034 sanitary sewer lines that run parallel to Summit Street, 8 feet off of the back of curb. Sanitary sewer line "A" (on sheet SI). begins at the existing manhole (near the lot line between Lots 2R and 3R) and runs southwest from station 0+00 to station I +25.73, at a grade of 0.60%. Sanitary sewer line "B'' (on sheet SI) begins at the existing manhole and runs northeast from station 0+00 to station I +50.73, at a grade of 0.60%. The pipe loading was calculated to be 0.023 cubic feet per second (cfs). This loading is calculated by considering a 4-plex on each lot. with each single unit having 3 bedrooms. One resident was assumed for each bedroom. totaling I2 residents per lot. A loading of I 00 gallons per day (gpd) was assumed for each resident to get the daily loading factor. The daily loading is multiplied by 3 to get the peak loading and I 0% of the daily loading accounts for infiltration. The infiltration is added to the peak loading to calculate the total loading. These calculations are shown below: Daily loading = 4 lots * I 2 residents per lot * 100 gpd per resident = 4800 gpd l oe1Jr'; ~~ et6h7 i /' /;.,._,e_ Peak loading = Daily loading * 3 = 4800 gpd * 3 = I4400 gpd Infiltration = Daily loading * O. I 0 = 4800 gpd * O. IO = 480 gpd Total loading = Peak loading + Infiltration = I 4400 gpd + 480 gpd = I4880 gpd Flow in cubic feet per second = flow in gallons per day * A * B Where: A = 0.13368 cubic feet per gallon B = 0.00001157 days per second * 0.13368 * 0.00001157 {o{) ({ow ,C bJ/,, £''/,;,.es '? According to Manning Pipe Theory, a 6" line graded at 0.6% can carry 0.436 cfs. where: Q = (1.49 / n) *A* R 2J3 * 5 0.5 Q = flow in cubic feet per second (cfs) n = Manning's roughness coefficient n = 0.013 for cast iron pipe A = area of pipe in square feet A= nd2 /4 A= 7t * (0 .5)2 I 4 = 0.19635 R = hydraulic radius = A I P where: A = area of pipe in square feet P = wetted perimeter = n * diameter Q R = 0 .1963;/=1~;708 = 0 .. 125 5tzDv!J be . lt/ lAfL r- S =slope of pipe= 0.006 {J"1der s/;eef h-it;1vi Q = (1.49 I 0.013) * 0.19635 * 0.1252 13 * 0.006°·5 Q = 0.436 cfs Since the ratio of loading to capacity is 0.0230/0.4360 = 0.053, the resulting velocity (from design tables) will be 0.513 of full flow velocity. Full flow velocity is calculated as follows: V =QI A full Where: V ru 11 = full flow velocity Q = full flow capacity in cfs = 0.436 cfs A = area of pipe in square feet = 0 .19635 ft2 Vru1i = 0.436 I 0.19635 = 2.22 ft/ sec The resulting velocity for a pipe flowing at 0.053 full, being 0.513 of full flow velocity, is thus: Vo.osaCull = 0.513 * 2.22 ft /SeC = 1.139 ft/SeC The two 6" diameter sewer lines flow into an existing 8" diameter line at the existing manhole (on sheet SI). A total of two manholes are required , and a standard distance of 500 feet or less between manholes is maintained throughout this project. Ref e r ence Desi~n and Construction of S a nitary a nd Storm Sewers. Prepared by a joint committee of the American Society of Civil Engineers (ASCE) and the Water Pollution Control Federation (WPCF): 1969. ASCE -Manuals and Reports on Engineering Practice No. 37. WPCF -Manual of Practice No. 9. Engineering Report For \\Tater Improvements To Block 14A, Southwood Valley -Section 19 College Station, Brazos County, Texas Prepared For: Tony Jones . 4475 Hicks Lane College Station, Texas 77845 Prepared By: GARRETT ENGINEERING CONSUi.. DIG IEll.GIC&WWW & lAllD llllVEYlllC ..... CART!R Clll!B PARKWAY, SUITE 1U • IRYAll, TEXAS 111112. (411) ..-.au • (_, ~ *April, 1995 * Engineering Report For \Vaterlrnprovernents To Block 14A, Southwood Valley -Section 19 College Station, Brazos County, Texas Prepared For: Tony Jones 44 75 Hicks Lane College Station, Texas 77845 Prepared By: GARRETT ENGINEERING *April, _..- ENGINEERING REPORT for water improvements to Block 14A, Southwood Valley -Section 19 College Stati on, BRAZOS COUNTY, TEXAS Biock 14A of Southwood Valley -Section 19 is situated adjacent to Summit Street, between Southwood Drive and Hilltop Drive in Southwood Valley, College Station, Brazos County, Texas. Block 14A consists of 4 lots, established within the bounds of a 1.64 acre tract. Additionally, the project is partially surrounded by developed property, but future expansion of the proposed facilities will likely not be necessary. Soils within the area have shown historically to be quite stable. No faults exist within the project area, and no stability problems are foreseen, other than those caused by the expansive clays typical of Brazos County. Water needs are met with a combination of 2" diameter and 1 1 /2" diameter Type "K" copper service line. Water line "A" is a 2" diameter line that ties into the 6" diameter line that runs parallel to Summit Street, and crossed under Summit Street (55.0 ft.) to the lot line between Lot 2R and Lot 3R (sheet W -1). Water line "B" is a 1 1 /2" diameter line that ties into the 6" diameter water line and crosses (55.0 ft.) under Summit Street to Lot 4R (sheet W-1). Water service to Lot lR comes from a 5 ft. long, 1 1 /2" diameter Type "K" copper service line that ties into the existing 8" water line that runs parallel to Southwood Drive. The meter loading was calculated to be 0.625 gallons per minute (gpm). This loading is calculated by considering a 4-plex on each lot, with each single unit having 3 bedrooms. One resident is assumed for each bedroom, with 100 gallons per day (gpd) assumed for each resident to get the daily loading factor. The daily loading is multiplied by 3 to the maximum loading per meter. These calculations are shown below: Daily loading = 3 residents per unit * 100 gpd per resident / J . = 300 gpd = 0.208 gpm fi--t:2 51 ze Peak loading = Daily loading * 3 = 300 gpd * 3 = 900 gpd = 0.625 gpm Total loading = Peak loading = 0.625 gpm COLLEGE STATION FIRE DEPARTMENT FIRE PREVENTION OFFICE To: Shirley Voll< Development Coordinator From : Tim Dedear Fire Protection Specialist February 9, 1995 Subject: Block 14A of Southwood Valley -Section 19 Water improvements In the future for Block l 4A, if a structure other than single family and duplexes are constructed, a fire hydrant may have to be installed at such location that no part of any structure shall be more than 300' from a fire hydrant as measured along the right of way of a public street or along an approved fire lane as the fire hose is laid off the fire truck. If single family or duplexes are constructed, a hydrant shall be within 500' of any part of the structure.