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HomeMy WebLinkAbout28 Development Permit 257 Saturn CNGDEVELOPMENT PERMIT PERMIT NO. 257 FOR AREAS OUTSIDE THE SPECIAL FLOOD HAZARD AREA RE : CHAPTER 13 OF THE COLLEGE STATION CITY CODE SITE LEGAL DESCRIPTION: A .55 acre tract of land that is part of a 3.0 acre tract in the Robert Stevenson League, IJMJ owned by Jack Winslow SITE ADDRESS: 4040 Texas Avenue South OWNER: Saturn Compressed Natural Gas DRAINAGE BASIN: North Fork -Lick Cree k TYPE OF DEVELOPMENT: This permit is valid for site clearing, grading as indicated on the approved site and grading plans. This permit also includes all site work as shown on the approved plans with the exception of the driveway and curbing construction within the right-of-way of State Highway 6 Frontage Road. The Contractor shall provide, install and maintain erosion control measures as necessary to keep all debris and sill on site .. The Contractor shall take all necessary precautions to prevent silt and debris from leaving the imm ediate construction site and entering city streets or area drainage ditch es or creeks in accordance with the City of College Station Drainage Policy and Design Criteria. Co ntracto r sha ll assure that establishment of vegetation occurs prior to removal of any si lt.fen cin g or hay bales used.for temporary erosion control. Contractor shall be responsible for any damage to alfjacent properties, city streets or infrastructure due to heavy machinety an d/or equipment as well as prevention of erosion and removal of siltation or sedimentation resulting.from th e p ermitted work. This p ermit 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 sha ll be in accordance with the plans and specifications submitted to and app ed by the City Engineer in the development permit application for the above named project of the codes and ordinances of the City of College Station that apply. Date Date Date I w CITY OF COLLEGE STATION Development Services 1) F;4ht.. ~ ~/-ftTAf~ s~r777 ,;:;;/l.. /f /~ fo S/ G.._... rr-vo F/91<. 8A-c-k:-ro us. 2) CAL'-Dce,e,.s \C ~L"-'O ewr- Wt-k::> -n-t€"" Ce>"'--'rlt.f)-c..~tZ_ ts /}A/O 7lfc_,~ /"fo'1ve-77/€" CC)-.,,,,,7"VfG~ Ce>/?"l c.-/;'"\/ ~ 5/6-J /f"5 t-v-'c?_c_ ' \ , .. ,.,.,.,.,.,.,.,.,.,.,.,.,.,. •l ·l ·l ·l ·.l ·l·l· l ·l ·l ·l ·I· l·l ·l·l ·I .,., ........................................... ,.,. ·I· !·I ·I· I ·I · I · .I ·I• I ·.I · I ·I· I · .I ·I• I ·I ·I• I ·I .,.,., .... ,.\•\"\"\"'".':':'·.':'·.':'·.':':'·.\·.': . OEVELOPH ENT S ERVI CES 02 /01/95 17:24 '5'4 0 9 764 3496 DEVELOPMENT SVCS *************************** *** ACTIVITY REPORT *** *************************** TRANSMISSION OK TX /RX NO . 0928 CONNECTION TEL 14093483349pp3 9 6 CON ECTION ID START TIME 0 2 /01 17:23 USAGE TIME 01'48 PAGES 2 RESULT OK Fax: ,at lg. 51:16 to From: Company : Phone: '1lo4--357D Fax: Date : :.1-f I Pages including this cover page: >-' ,., . ,., •\. \•\ .,. \•\• \• \ .,. '•\ . . ~~ ~~~ -~ ~~ ~~~~ ~~~ ~~~ ~~~~ ~~~!~! ~!~! ~!,. ·I · I · .I ·I · /·I ·I• I ·I · I ·I · I·/ ·I •l •l • l •l •l •l·I ·\·'\·\·'\·\·'\•\•\·\·\·\•\•\•\·\•\·\·\•\·\•\·\• ! ·I ·I · I · I ·I· I •l •l •l ·I· l •l · l ·l ·I ·I •I • I •I ·I ·I ·I • l •I ~'.: ~ :~ :~ :~:~ :~:~~~:~:~ :~: ~ :~ :~~~ :~:~:~: ~:~ :~~ ~:~~ ~:~ ~~ ~ ~ \. ~·. J. J ·I· I ·.I ·I · l ·l · l·l ·/·I ·I · I· I · I • I ·I• I ·I ·I• l •l • J · I •I • I •I• I I ,. '.,.,.,. ,., .,.,.,.,.,.'"'''. ,., .,.,.,.,.,.,. ,.,. ,.,.,.,.,. r , ~ ~ ~ ~~ ~~~ ~ ~~~ ~~~~~~~ ~~~ ~ ~! ~ ~~: ~ ~~ ~ ~~ ~ ~~ ~ ~~~ ~ ~~ ~ ~~ !~ ~~ ~~~ ~ ~ ~~ ~~,. (409 ) 764 -3 570 C409) 764 -3496 FAX l4J 001 DEVELOPMENT PERMIT PERMIT NO. 257 ~ FOR AREAS OUTSIDE THE SPECIAL FLOOD HAZARD AREA RE: CHAPTER 13 OF THE COLLEGE STATION CITY CODE SITE LEGAL DESCRIPTION: A .55 acre tract of land that is part of a 3.0 acre tract in the Robert Stevenson League, that is owned by Jack Winslow SITE ADDRESS: 4040 Texas Avenue South OWNER: Saturn Compressed Natural Gas DRAINAGE BASIN: North Fork -Lick Creek TYPE OF DEVELOPMENT: This permit . is valid for site clearing, grading as indicated on the approved site and grading plans. This permit also includes all site work as shown on the approved plans and the driveway and curbing construction within the right-of-way of State Highway 6 Frontage Road in accordance with the approved TXDO T permit. The Contractor shall provide, install and maintain erosion control measures as necessary to keep all debris and silt on site. The Contractor shall take all necessary precautions to prevent silt and debris from leaving the immediate construction site and entering city streets or area drainage ditches or creeks in accordance with the City of College Station Drainage Policy and Design Criteria. Contractor shall assure that establishment of vegetation occurs prior to removal of any silt fencing or hay bales used for temporary erosion control. Contractor shall be responsible for any damage to adjacent properties, city streets or infrastructure due to heavy machinery and/or equipment as well as prevention of erosion and removal of 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 Contractor Date Owner/ Agent Date ~~J;Jw~Mf~ Saturn Gas Systems, Inc. Mr. Brett Mccully Project Engineer City of College Station Planning Office College Station, Texas 77842 February 9, 1995 Dear Brett: Six Greenspoint Pl aza 12450 Greenspoi nt Drive, Su ite 1260 Hou ston , Texas 77060-1916 (713) 874-2103 FAX (713 ) 874-2107 Saturn Gas proposed to use concrete on our Site no. 5 located at 4040 Texas Avenue College Station. This surface is planned instead of asphalt in order to make a better location. We intend to pour 6 ~nches of concrete ;.10. 5 sack mix with a 2<nch minimum sand pad. 3/~inch rebar will be used with \~./inch centers with metal key way joints. All proposed work will be done in accordance with the City of College Station standards. &~l }Zj itted, Whitney T ~- 7 Veronica Morgan City of College Station Engineering Department College Station, Texas 77842 December 13, 1994 Dear Ms. Morgan: Six G ree n sp o in t Pl aza I 24SO Green sp o int Drive, Suit e 1 260 H o u ston , Texas 77060-19 1 6 (7 13) 874 -2103 FAX (7 1 3) 874 -2107 (71?)818-IS~ ~k @a1) 348 -(AM- ~) ~-5460 RECElVED DEC \ 9 1994 In response to your letter of November 29, 1994 relative to details of the entrance to our proposed development at 4040 Texas Avenue in south College Station, we would like to propose, in light of the physical situation of culverts, that we instead install what might be termed a low water crossing. Attached are sketches which show in profile the relative elevations of the ditch bottom, the top of the Highway 6 frontage road, and the development site. Also included is a profile of the re-enforced concrete slab which can be installed as a low water crossing in accordance with TEXDOT. We view this as a very practical way to install a transition from the Highway 6 frontage road to our proposed development without interfering with drainage of any possible magnitude. We hope that you will agree. Respectfully, :4/4 Whitney T. Smith P.S. If this is not amenable to you, I would appreciate you calling me to let me know so that we can make other arrangements. We need to commence as rapidly as possible. Access Driveway Regulations The State Highway and Public Transportation Commission, in recognition of its responsbility for the safety and utlility of public highways under its jurisdiction, has directed the adoption of rules and regulations to accomplish a coordinated develop- ment between highways and abutting property. For this purpose, the booklet entitled "Regulations for Access Driveways to State Highways" was published and adopted, setting out departmental policies to regulate construction and maintenance of a cc ess driveway facilities. ---- Sketch of Installation -_J ~··· ·c:•l 'X.2,1' T-EXAS STATE CANOPY SERVICE ISLA U SEE ENLARGED I AN SllEET 2 - 90· 6 FRONTAGE ROAD HIGHWAY SATURN GAS SYSTEMS, INC. 4040 TEXAS AVENUE, COLLEGE STATION, TEXAS 1. SECTION A-A invert elevations of Hwy 6 frontage road ditch ..-- 3. HIGHWAY 6 FRONTAGE 4. ELEVATION -103.7' 9. SECTION E - B profile -across Highway 6 Frontage Drainage Ditch '· ' 'S. DITCH BOTTOM 6. ELEVATION -100.8' 2. SCALE 1 II;: 10 I 1. DEVELOPMENT SITE -~. ELEVATION -102.4' 10. SCALE VERTICLE-l" = 10' HORIZONATAL -l" = - \ DEVELOPMENT SITE SECTION A - A invert elevations Highway 6 drainage ditch A t s HIGHWAY 6 FRONTAGE ROAD 4 . .3 2 A :-1 1. PROFILE OF LOW-WATER CROSSING ~ 1. Highway 6 Frontage Road -~~-... ___ ~Concret slab per TEXDOT specs 6 Asphalted Development r-= --~.I' .. _:__ ..... --_~=r 3. Elevation-103--:--1 ·1 --·-.. _. -~::::::;:::::e:~~:z:;~-~==r site i. Elevation -102.4' 5. Elevation -100.8' I I I . I i I I I I I I i ! 17850.0 ~ 12 14 FIGURE 44 18 I-w w u.. z _J 0 16 er I-z r_ .. 0 u I-w _J I-14 :::> 0 er 0 u.. _J 0 "' ::.: 12 ::i:: u.. 0 V'I w :::> _J < 10 > ~ c 0 I-w w u.. z 8 _J 0 0: I-z 0 u I-6 w _J 3: er 0 u.. ::.: ::i:: u.. 0 V'I w :::> _J < > . I . ~~110M/\~ ;; FIGURES o· ...----. S o,.,.D~~~-r~ CULVERT CAPACIT~o\Y v~·i· \ 18-INCH DIAMETER PIPE MW;: .... -i ..... I' j'' t : . 1- 241 -1 --:-. ~ . -. . ! : i ~ . O '--~......c~~-'-~~.:....~.......i~~~~~-'-~~~~-'--'-~~-'-~'--,__--'-~.J...-1 8 12 16 20 24 28 CULVERT DISCHARGE QIN CUBIC FEET PER SECOND FINAL DRAINAGE REPORT OF SATURN GAS SYSTEMS, INC. AT 4040 TEXAS AVENUE, SOUTH STATE HIGHWAY 6 COLLEGE STATION, TEXAS The above captioned facility will be located on the west side of State Highway 6 abutting on the frontage road between Graham Road and Birmingham Road. It will be adjacent to Winslow's Body Shop which is on Graham Road and Highway 6 frontage road. The only other facility in the area is a veterinary clinic on Graham Road adjacent to Winslow's Body shop. Primary drainage for this area is the Navasota River. This river is fed by Lick Creek, the secondary system which lies two tenths mile to the south of the Saturn Gas System Inc. site. Drainage in the immediate vicinity is southerly across the ground surface which slopes toward Lick Creek. Much of the drainage from the site and the immediate area flows naturally into the highway system and is carried to Lick Creek. There are no surrounding developments other than the body shop and the veterinary clinic mentioned earlier. The deve lopment area is 0.53 acres, more or less, and being a part of that 3. 0 acre tract in the Robert Stevenson League in Brazos County, Texas, being the same land described in a deed from Roy w. Kelly et ux to Jack Winslow et ux dated March 6, 1972, and recorded in Volume 301, page 787, of the Brazos County Deed Records, said 0. 53 acres being more particularly described as follows: Beginning at the north-most corner of said 3.0 acre tract: Thence South 28 degrees 19 minutes East 150.0 feet, to a point in the Northeast line of said 3.0 acre tract and the west right-of-way line of State Highway 6; Thence South 44 degrees 39 minutes West 165.0 feet; Thence North 28 degrees 19 minutes West 150.0 feet to a point in the Northwest line of said 3.0 acre tract; Thence North 44 degrees 39 minutes East 165.0 feet to a PLACE OF BEGINNING and containing 0.53 acres of land, more or less. The area to be developed is presently covered with common pasture grasses, which will be disturbed only to the extent necessary to effect development. Since the area in question is so limited in size, there are no primary or secondary drainage systems contained therein. The purpose of this development is to establish a strategically located compressed natural gas refueling facility in the Sout h College Station area. At the location chosen, three ingredients of a good site are present: 1. Abundant high-pressure natural gas from a line paralleling Graham Road. 2. Electrical power as required. 3. High density local and through traffic. Compressed natural gas (CNG) is deemed the best alternative fuel compared to gasoline and diesel fuels because it is the cleanest burning of the fuels mentioned. used will be domestically produced. Also, the natural gas According to the Flood Insurance Rate Map of Brazos County, Texas and Incorporated Areas, the development area is described as being outside the five hundred year flood plain. Only 5830 square feet of the area developed will be paved. A four inch rain on the paved area would cause less than 0.05 acre- feet of rapid run-off. This will be caused to flow off the paved area of the development into the highway drainage system at the southern end of the paved area. Drainage from the remainder of the 0.53 acre tract will not be altered appreciably from its present adequate state. Planned construction will not create constraints. Further, the adjacent property on the north side of the tract to be developed has had a considerable quantity of fill placed thereon which serves to divert runoff from higher ground to the north. This tends to alleviate the problem of drainage across the area of development. In addressing the influence of drainage from adjacent areas, run-off volumes anticipated both PRE-and POST-construction will be projected. Two areas are considered; the first lies to the north of the construction between Rock Prairie Road and Birmingham Road adjacent to SH 6, and the second lies fully within the Winslow property and includes the Saturn Site. They are designated as Area I and Area II, respectively. Calculations are made for the effects of 5 yr., 10 yr., 25 yr., 50 yr., and 100 yr., storms are anticipated both prior to and after construction. The formula used for calculating run-off discharges is Q=CIA, where: Q = Discharge in cubic feet per second C = Run Off coefficient I Rainfall Intensity in inches per hour A Drainage area in acres Runoff coefficients C are taken from an ASCE table. Rainfall Intensity I is calculated from the formula I= b/(tc + d) raised to the e power where b, d and e are constants listed in the TEX-DOT Bridge Division Hydraulic Manual, Table 6. AREA I t\ (\_ PRE: Constants: A= 19.2 ac; tc = 50 min; c = 0.10 ~ f POST: Constants: A= 19.2 ac; tc = 40 min; c = 0. 20 fJ~ PRE POST 5 yr. 6.02 13.98 11x?~v 10 yr. 6.89 15.89 1 ~~··JY . 25 yr. 7.95 18.31 50 yr. 9.07 20.87 ¥/ 100 yr. 9.45 21.67 NOTE: It is estimated that at least half of this runoff drops into the main State Highway 6 drainage by following the ON RAMP and by overflowing the curbs along the sides of the frontage road. This is considered in the later calculation of total runoff passing through the Graham Road culvert at SH 6. AREA II PRE: Constant: A = 1. 6 ac; tc = 50; c = 0.10 q C.• • POST: Constant: A = 1. 6 ac; tc = 40; c = 0.20 e· ----PRE -t, ': \0 ,.,;._, POST (. 5 yr. 1.17 10 yr. 1. 33 25 yr. 0.76 1.52 50 yr. 0.87 1. 74 100 yr. 0.90 NOTE: All of the above calculated volume will pass through the Graham Road culvert. The maximum volume expected to enter the drainage ditch on the frontage road side of the Saturn site is as follows: AREA 1 II Runoff + 1.80 # This is also the maximum flow expected throught the culvert at Graham Road and SH 6. The capacity of the culvert at Graham Ro ad and SH 6 is determined as follows: is dual 18 inch x 24 feet. of flow through culvert: 5 seconds v;' Q Q"/ \JA -v = x 9/12) x 24 x 2/5 A V :Fi'(r 2.. 3.146 x 24 x 2/5 = x # 84.8 cu. ft./ ? 0 16.96 cubic feet This value is well above the calculated maximum runoff to be handled by the culvert in question. An Inspection of the area in this immediate vicitnity following the flood rains of October, 1994 confirmed that this culvert adequatedly handled the runoff coming through it. There are presently no drainage problems associated with the area of development. Again, planned construction will not result in constraints harmful to either the area of development or to adjacent properties. The burden on existing drainage facilities will not be changed. The same culvert as at Graham Road and SH 6 is planned and should be adequate at that point even after the surrounding area has developed. There will be no detention/retention storage or outlet works. CONCLUSIONS To the best of my knowledge, the development plan is submitted in complaince with Standards of the City of College Station Drainage Policy and Design Standards. This development is located outside the 500 year floodplain and will pose no hazard or cause any damage from stormwater flows. Respectfully Submitted, State of Texas No. 16833 / Richard D . Mills,P.E . 12450 Greenspoint Drive, Suite 1260 Houston.TX 77060-1916 September 22 , 1994 City of College Station : Submitted herewith is a Final Drainage Report pertaining to the Saturn Gas Systems Inc.development of a compressed natural gas(CNG) refueling station to be located at 4040 Texas Avenue.South State Highway 6, College Station , Texas . In the opinion of the writer, no drainage problems will occur either on site or off site as a result of this development. Respectfully Submitted, ~~~/,??~ Registered Professional Engineer State of Texas No . 16833 / ..... '·, ~\ .. '~ .~J-1.:.r J !. ... Zic o::, .. .. / CERTIFICATION SHEET I hereby certify that this report for the drainage design of Saturn Gas System Inc . was prepared under my supervision in accordance with the provisions of the City of College Station Drainage Policy and Design Standards for the owners thereof. «~ /' ~eCl8SSi008iEng1neer State of Texas No . 16833 ANAL DRAINAGE REPORT OF SA nJRN GAS SYSTEMS INC. AT ~TEXAS AVENUE, SOUTH STATE HIGHWAY 6, COLLEGE STATION , TEXAS The above captioned facility will be located on the west side of State Highway 6 abutting on the frontage road between Graham Road and Birmingham Road . It will be adjacent to Winslow's Body Shop which is on Graham Road and Highway 6 frontage road. The only other facility in the area is a veterinary clinic on Graham Road adjacent to Winslow's Body Shop. Primary drainage for this area is the Navasota River . This river is fed by Rocle Creek, the secondary system which lies one tenth mile to the south of the Saturn Gas System Inc. site. Drainage in the immediate vicinity is southerly across the ground surface which slopes toward Rocle Creek. Much of the drainage from the site and the immediate area flows naturally into the highway system and is carried to Rock Creek. There are no surrounding developments other than the body shop and the veterinary clinic mentioned earlier. The development area is 0 .53 acres, more or less.and being a part of that 3.0 acre tract in the Robert Stevenson League in Brazos County, Texas , being the same land described in a deed from Roy W .Kelly et ux to Jack Winslow et ux dated March 6,1972, and recorded in Volume 301, page 787, of the Brazos County Deed Records , said 0 .53 acres being more particularly described as follows : Beginning at the north-most comer of said 3 .0 acre tract: Thence South 28 degrees 19 minutes East 150.0 feet, to a point in the Northeast line of said 3 .0 acre tract and the west right-of-way line of State Highway 6 ; Thence South 44 degrees 39 minutes West 165.0 feet; Thence North 28 degrees 19 minutes West 150.0 feet to a point in the Northwest line of said 3 .0 acre tract; Thence North 44 degrees 39 minutes East 165.0 feet to a PLACE OF BEGINNING and containing 0 .53 acres of land, more or less. The area to be developed is presently covered with common pasture grasses, which will be disturbed only to the extent necessary to effect development. Since the area in question is so limited in size, there are no primary or secondary drainage systems contained therein. The purpose of this development is to establish a strategically located compressed natural gas refueling facility in the South College Station area . Af the location chosen, three ingredients of a good site are present: 1.Abundant high-pressure natural gas from a line paralleling Graham Road. 2.Electrical power as required . 3 . High density local and through traffic. Compressed natural gas(CNG) is deemed the best alternative fuel to gasoline and diesel fuels because it is the cleanest burning of the fuels mentioned. Also, the natural gas used will be domestically produced . According to the Flood Insurance Rate Map of Brazos County, Texas and Incorporated Areas , the development area is described as being outside the five hundred year ftood plain . Only 5830 square feet of the area developed will be paved. A four inch rain on the paved area would cause less than 0 .05 acre-feet of rapid ru~. This will be caused to ftow off the paved area of the development into the highway drainage system at the southern end of the paved area. Drainage from the remainder of the 0 .53 acre tract will not be altered appreciably from its present adequate state . - r ( Planned construction will not create constraints . Further, the adjacent property on the north side of the tract to be developed has had a considerable quantity of fill placed thereon which seNes to divert runoff from higher ground to the north . This tends to alleviate the problem of drainage across the area of devlopment. There are presently no drianage problems associated with the area of development. Again, planned constuction will not result in constraints harmful to either the area of development or to adjacent properties . The burden on existing drainage facilities will not be changed . One culvert will be installed in the access from the developed site onto the Highway 6 frontage road . This will be of eighteen inch concrete-equal in capacity to the culvert under Graham Road . There will be no detention/retention storage or outlet works. CONCLUSIONS To the best of my knowledge , the following development plan is submitted in compliance with Standards of the City of College Station Drainage Policy and Design Standards . This development is located outside the 500 year flood plain and will post! no hazard or cause damage from stormwater flows . Respectfully Submitted , ~~~~ Registe_red Professional Engineer State of Texas No. 16833 ... , FINAL DRAINAGE REPORT OF SATURN GAS SYSTEMS, INC. AT 4040 TEXAS AVENUE, SOUTH STATE HIGHWAY 6 COLLEGE STATION, TEXAS The above captioned facility will be located on the west side of State Highway 6 abutting on the frontage road between Graham Road and Birmingham Road. It will be adjacent to Winslow's Body Shop which is on Graham Road and Highway 6 frontage road. The only other facility in the area is a veterinary clinic on Graham Road adjacent to Winslow's Body shop. Primary drainage for this area is the Navasota River. This river is fed by Lick Creek, the secondary system which lies two tenths mile to the south of the Saturn Gas System Inc. site. Drainage in the immediate vicinity is southerly across the ground surface which slopes toward Lick Creek. Much of the drainage from the site and the immediate area flows naturally into the highway system and is carried to Lick Creek. There are no surrounding developments other than the body shop and the veterinary clinic mentioned earlier. The development area is 0.53 acres, more or less, and being a part of that 3. 0 acre tract in the Robert Stevenson League in Brazos County, Texas, being the same land described in a deed from Roy W. Kelly et ux to Jack Winslow et ux dated March 6, 1972, and recorded in Volume 301, page 787, of the Brazos County Deed Records, said 0. 53 acres being more particularly described as follows: Beginning at the north-most corner of said 3.0 acre tract: Thence South 28 degrees 19 minutes East 150.0 feet, to a point in the Northeast line of said 3.0 acre tract and the west right-of-way line of State Highway 6; Thence South 44 degrees 39 minutes West 165.0 feet; Thence North 28 degrees 19 minutes West 150.0 feet to a point in the Northwest line of said 3.0 acre tract; Thence North 44 degrees 39 minutes East 165.0 feet to a PLACE OF BEGINNING and containing 0.53 acres of land, more or less. The area to be developed is presently covered with common pasture grasses, which will be disturbed only to the extent necessary to effect development. Since the area in question is so limited in size, there are no primary or secondary drainage systems contained therein. The purpose of this development is to establish a strategically located compressed natural gas refueling facility in the South College Station area. At the location chosen, three ingredients of a good site are present: 1. Abundant high-pressure natural gas from a line d. paralleling Grah~ Road. 2. Electrical power as required. 3. High density local and through traffic. Compressed natural gas (CNG) is deemed the best alternative fuel compared to gasoline and diesel fuels because it is the cleanest burning of the fuels mentioned. Also, the natural gas used will be domestically produced. According to the Flood Insurance Rate Map of Brazos County, Texas and Incorporated Areas, the development area is described as being outside the five hundred year flood plain. Only 5830 square feet of the area developed will be paved. A four inch rain on the paved area would cause less than 0.05 acre- feet of rapid run-off. This will be caused to flow off the paved area of the development into the highway drainage system at the southern end of the paved area. Drainage from the remainder of the 0.53 acre tract will not be altered appreciably from its present adequate state. Planned construction will not create constraints. Further, the adjacent property on the north side of the tract to be ~ developed has had a considerable quantity of fill Jpced thereon which serves to divert runoff from higher ground to the north. This tends to alleviate the problem of drainage across the area of development. In addressing the influence of drainage from adjacent areas, run-off volumes anticipated both PRE-and POST-construction will be projected. Two areas are considered; the first lies to the north of the construction between Rock Prairie Road and Birmingham Road adjacent to SH 6, and the second lies fully within the Winslow property and includes the Saturn Site. They are designated as Area I and Area II, respectively. Calculations are made for the effects of 5 yr., 10 yr., 25 yr., 50 yr., and 100 yr., storms are anticipated both prior to and after construction. The formula used for calculating run-off discharges is Q=CIA, where: Q Discharge in cubic feet per second C Run Off coefficient I Rainfall Intensity in inches per second A Drainage area in acres Runoff coefficients C are taken from an ASCE table. Rainfall Intensity I is calculated from the formula I= b/(tc + d) raised to the e power where b, d and e are constants listed in the TEX-DOT Bridge Division Hydraulic Manual, Table 6. AREA I PRE: Constants: A= 19.2 ac; tc = 50 min; C = 0.10 POST: Constants: A= 19.2 ac; tc = 40 min; C = 0.20 PRE POST 5 yr. 6.02 13.98 10 yr. 6.89 15.89 25 yr. 7.95 18.31 50 yr. 9.07 20.87 100 yr. 9.45 21.67 NOTE: It is estimated that at least half of this runoff drops into the main State Highway 6 drainage by following the ON RAMP and by overflowing the curbs along the sides of the frontage road. This is considered in the later calculation of total runoff passing through the Graham Road culvert at SH 6. AREA II PRE: Constant: A= 1.6 ac ; tc = 50; c = 0.10 POST: Constant: A= 1.6 a c; tc = 40 ; C = 0.20 PRE POST 5 yr. 0.58 1.17 10 yr. 0.66 1. 33 25 yr. 0.76 1. 52 50 yr. 0.8 7 1. 74 1 0 0 yr. 0 .9 0 1. 80 NOTE: All of the above calculated volume through the Graham Road culvert. will pass The maximum volume expected t o enter the drainage ditch on the fr o ntage road side of the Saturn site is as foll o ws: AREA 1 Runoff /2 + Area II Ru noff = 21.6 Yz + 1.80 1 2 .63 cfps This is also the maximum flow expected throught the culvert at Graham Ro ad and SH 6. The capacity of the culvert at Gr a ham Road and SH 6 is determined as follows: Culvert is dual 16 inch x 24 feet. As s umed time of fl o w t h r o ugh culvert: 5 seconds v = 3.1416 x (9/12 x 9/12) x 24 x 2 /5 3.146 x 0.5625 x 2 4 x 2 /5 = 84 .8 cu. ft ./ 5 16.96 cubic feet per second This value is well above the calculated maximum runoff to be handled by the culvert in question. An Inspection of the area in this immediate vicitnity following the flood rains of October, 1994 confirmed that this culvert adequatedly handled the runoff coming through it. There are presently no drainage problems associated with the area of development. Again, planned construction will not result in constraints harmful to either the area of development or to adjacent properties. will not be changed. The burden on existing drainage facilities The same culvert as at Graham Road and SH 6 is planned and should be adequate at that point even after the surrounding area has developed. There will be no detention/retention storage or outlet works. CONCLUSIONS To the best of my knowledge, the development plan is submitted in complaince with Standards of the City of College Station Drainage Policy and Design Standards. This development is located outside the 500 year floodplain and will pose no hazard or cause any damage from stormwater flows. Respectfully Submitted, Richard D. Mills, P.E. State of Texas No. 16833 I ACCOUNT NO. ______________ _ ) RECEIVED OF _--+--A-+-4--+-+,.1,,.-<<....>....µ...<J.4'----"-'--""'*-'-~=+-1--~-------- FOR -,.....+---+----=---~--=D---=-m......,_~~-;-+--Jj __ _ I ~ Paid by_ Check l l~cash __ GENERAL NOTES1 1. THERE IS NO 100 YEAR flOCO PlA1H CN CR THE PR()>()S[D PRO..CCT SITE. ADJACOH TO 2. THER£ ARE NO DlSTNG ClJR9 CUTS CN THE SAME OPPOSITE Sl DE Of TH[ STRITT. AND CR l OOJBL£ UN£ 0CN0 TES 6 • a.JRS . 4 . NO WASTE I NO Nffi) roo OUt.IPSITRS. -~~'---. STATION N0.5 LOCATION MAP STATE HIGHWAY 6 SOUTH 4040 TEXAS AVENUE C OLLEGE STATION, TEXAS SITE AND GRADING PLAN ~·· ~ .r/Wast S ···1:tation Designed R.P . Da t e 9/26/94 Drawn J.B . Scale : 1" = 20' Checked R.P. Project No : 94180 ·• .• . ·, . -. : -... ---. • ,,; '·, J"'· _:;· ... ;/'. .- . : . . -·. '. . :~:·_ :: . . . ·. ;" ,):. · ... '.I ~ ; .· ,. ..;... ,., ........ ·· ,.... . . .. _, ~ -. ~ .· . -.· • '!'" -,:" "' ·,--· .... ,,. ..... . ·: .. l .... _ ,? .. _ DEVELOPMENT PERMIT PERMIT NO . 257 FOR AREAS OUTSIDE THE SPECIAL FLOOD HAZARD AREA RE : CHAPTER 13 OF THE COLLEGE ST A TI ON CITY CODE SITE LEGAL DESCRIPTION: A . 55 acre tract of land that is part of a 3. 0 acre tra ct in th e Robert Stevenson League, IMJ owned by Jack Winslow SITE ADDRESS: 4040 Texas Avenue South OWNER: Saturn Compressed Natural Gas DRAINAGE BASIN: North Fork -Lick Creek TYPE OF DEVELOPMENT: This permit is va lid for site clearing, grading as indi cated on the approved site and grading plans. This permit also includes all site work as shown on the approved plans with the exception of the driveway and curbing construction within the right-of-way of State Highway 6 Frontage Road. The Contractor shall provide, install and maintain erosion control measures as necessary to keep all debris and silt on site .. The Contractor shall take all necessary precautions to prevent silt and debris from leaving the immediate construction site and entering city streets or area drainage ditche s or creeks in accordance with the City of College Station Drainage Policy and Design Criteria. Co ntractor shall assure that establishment of vegetation occurs prior to removal of any si lt.fencing or hay bale s used for temporaty erosion control. Contractor shall be responsible for any damage to adjacent properties, ci ty s treets or infrastrncture due to heavy machine1y and/or equipment as well as prevention of erosion and removal of siltation or sedimentation resulting.from the permitted work. This permit expires s ix 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 app ed by the City Engineer in the development permit application for the above named project a of the codes and ordinances of the City of College Station that apply . Date 1/w/1~ I !/J-~/?J Date J/2 G /<Js · Date I DEVELOPMENT PERMIT PERMIT NO . 257 FOR AREAS OUTSIDE THE SPECIAL FLOOD HAZARD AREA RE : CHAPTER 13 OF THE COLLEGE ST A TION CITY CODE SITE LEGAL DESCRIPTIO N: A .55 acre tract <?f land that is part of a 3. 0 acre tract in the Robert Stevenson League, IJMi owned by Jack Winslow SITE AD D RESS: 4040 Texas Avenue South O WNER: Saturn Compressed Natural Gas DRAINAGE BASIN: North Fork -Lick Creek TYPE OF D EVELOPMENT: This permit is valid for site clearing, grading as indicated on the approved site and grading plans. This permit also includes all site work as shown on the approved plans with the exception of the driveway and curbing construction within the right-of-way of State Highway 6 Frontage Road. The Contractor shall provide, install and maintain erosion control measures as necessary to keep all debris and silt on site .. The Contractor shall take all necessary precautions to prevent silt and debris from leaving the immediate construction site and entering city streets or area drainage ditches or creeks in accordance with the City of College Station Drainage Policy and Design Criteria. Contractor shall assure that establishment of vegetation occurs prior to removal of any si It fencing or hay bales used for temporary erosion control. Contractor shall be responsible for any damage to adjacent properties, city streets or infrastructure due to heavy machine1y and/or equipment as well as prevention of erosion and removal of 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 constructi o n, eros ion, and se dimentatio n 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. Al l development shall be in accordance with the plans and specifications submitted to and app ed by the City Engineer in the development permit ap pl ication for the above named project of t he codes and ordinances of the City of College Station that apply . Date ilwMs-I !/J-~!1_)- Date J/2 0 /<Js · Date I ~-w-C~:~m~~~~~~~~~~~~~~N College Station, Te xas 77842-0960 January 17 , 1995 Texas Department of Transportation P . 0 . Box 3249 Bryan, TX 77805 Attn : Jay Page RE: Driveway Construction Permit (409) 764-3570 Saturn Compressed Natural Gas Station West Highway 6 Frontage Road , approximately . 200 feet north of Graham Road Dear Jay, Attached please find the latest revision to the driveway design for the subject parcel. We have coordinated this design with the applicant , and agree that this is the most preferred solution to the drainage situation in this area . Please review the application , and provide a response to me as soon as practical. Should there be any questions or comments, please do not hesitate to call. Sincerely, 6/41rt/ Brett McCully Project Manager cc : v'Veronica Morgan, Assistant City Engineer Whitney Smith, Saturn Gas Systems, Inc. ;~-~!-r ~bli ~.T~~~-P~~t~~i~n Fonn 1058-Rcv. 12 -86 To: Permit to Construct Access Driveway }-.acilities on Highway Right of Way Hwy. ___ Permit No. __ _ Control Section \ \ \ The Slate Department of Highways and Public Transportation, hereinafter called the State, hereby authorizes _____ _ SATURN GAS SYSTEMS, INC. , hereinafter called the grantee, to (re) construct an access driveway on the highway right of way abutting highway no. in BRAZOS County, located 4 04 0 TEXAS AVENUE Subject to the following: l. The grantee is responsible for all costs associated with the construction of this access driveway. 2. Design of facilities shall be as follows and/or as shown on sketch: DESIGN OF FACILITIES SHOWN ON SKETCH AND ACCORDING TO REGULATIONS. All construction and materials shall be subject to inspection and approval by the State. 3 . Maintenance of facilities constructed hereunder shall be the responsibility of the grantee, and the State reserves the right to require any changes, maintenance or repairs as may be necessary to provide protection of life or property on or adja- cent to the highway. Changes in design will be made only with approval of the State. 4 . The Grantee shall hold harmless the State and its duly appointed agents and employees against any action for personal injury or property damage sustained by reason of the exercise of this permit. 5. The Grantee shall not erect any sign on or extending over any portion of the highway right of way, and vehicle service fixtures such as service pumps, vender stands, or tanks shall be located at least twelve (12) feet from the right-of-way line lo ensure that any vehicle services from these fixtures will be off the highway. 6 . This permit will become null and void if the above-referenced driveway facilities are not constructed within six (6) months from the issuance date of this permit. 7. The Grantee will contact the State's representative telephone ( ) at least twenty-four (24) hours prior to beginning the work authorized by this permit. Date of Issuance-------------------- State Department of Highways and Public Transportation District Engin«r The undersigned hereby agrees to comply with the terms and conditions set forth in this permit for const , "on of an access driveway on the highway right of way. / Date:_~(c,2-+-/~/ 3-t-/--'7__,_Y ____ _ ~ I I J A •N _ 1 7 _ 9 5 T U E 1 1 : 3 7 P A R T E N 0 P E R A T I N G INC P.02 '· \ Access Driveway Hegulatious --Tl1t Sl<llC I lighwi\y :tml l'u!Jlic Transp~Clalion Co111111iuion, in recognition or tu rcspon.sbitity ror <he s:t[c~y ind utlilHy ()I ""lilic lii~hw:\y~ under iu j11ris<liction, h:\.4' directed lhc ado!'lio11 of rules ancl cc&ul:ltio11l tu accomplish a cuordiualeu dcvclvp 111c111 l1r •1wr.1:11 hi).thw:ty~ :rnd i1lJ1111i11c propctly. f'or this purpu.<c, the tx>oklc:l entitled "Rc:g11l<ition.s for l\cc:e.u Urivcw~y~ 11 rt1;1 rt! I lhd1\11:ty~" w:i ... puhli.~hc:u :11111 ;11.Jul'tccl •. ti:tti11g oul dcp:11u11c11l:\I pulidcs tu regulate cv•utructiun :tnd m:i i11 tc11:111cc c•• :\c.:c:e ... ~ d1 i\·cw:ty fm:ilillcs. I I \ J I . I ( J I . t / · I I I Skeh:b or Installation , 103. 7 -03' Grade Break; Flow line + 6" - .. ··--·--·····-·----- ____ ...--------~ -- SJ\TURN GhS SYSTEMS, INC. 4o1 o '!'EXJ\S "VENUE, COLLEGE 51'1\'l'ION, ·ri:::<f\S - - ----------- January 6, 1994 Saturn Gas Systems , Inc. Six Greenspoint Plaza CITY OF COLLEGE STATION Po st Office Box 9960 1101 Texas Avenue College Station, Texas 77842-9960 (409) 764-3500 12450 Greenspoint Drive, Suite 1260 Houston, TX 77060-1916 Attn : Whitney Smith Re: CNG Compressor Station, 4040 Texas Avenue, College Station TX Driveway Design Dear Mr. Smith, Yesterday I spoke with Richard Mills regarding the design options of this driveway , and he faxed me another concept, that of using a raised asphalt berm across the driveway to prevent runoff from entering the site . After reviewing the sketch provided, we do not feel that this is an acceptable alternative, specifically because the berm would be within the public right of way, which is not allowed. I would like to restate the two op t ions available for this access point. First, because the site frontage is not presently curbed, you may place culverts under the driveway and construct what we call a rural driveway which does not include any curbing . The State requires that th e culverts be sized to pass a 5 year stom1 , so a brief hydrologic and hydraulic study would have to be prepared. Your second option is to install curbing along the frontage road , and construct a standard urban driveway, which is curbed , and is designed to confine the street drainage so it does not enter the site . This option would not require culvert(s), nor a drainage study . The curbing on the frontage road wou ld only need to extend from the existing curbing at the northern property comer to a point 15 feet south of the driveway point of curvature . We understand the difficulties involved with the relative elevations of the site and the frontage road , however we have many locations within the City where worse situations have been adequately handled with the second option mentioned above . As before, please contact me with any questions that you may have. Sincerely, i11-/Jft/ Brett McCully Project Engineer cc : '1 veronica Morgan , Assistant City Engin eer Jay Page, TXDOT Pem1it Office Home of Texas A&M University ~--.• Richard D . Mills ,P .E . 12450 Greenspoint Drive, Suite 1260 Houston , TX 77060-1916 September 22, 1994 City of College Station : Submitted herewith is a Fi nal Drainage Report pertaining to the Saturn Gas Systems Inc.development of a compressed natural gas(CNG) refueling station to be located at 4040 Texas Avenue,South State Highway 6 , College Station , Texas . In the opinion of the writer , no drainage problems will occur either on site or off site as a result of this development. Respectfully Submitted, ~~4 ~ Registered Professional Engineer State 'of· Texas No . 16833 CERTIFICATION SHEET I hereby certify that this report for the dra i nage design of Saturn Gas System Inc. was prepared under my supervision in accordance with the provisions of the City of College Station Drainage Policy and Design Standards for the owners thereof. FINAL DRAINAGE REPORT OF SATURN GAS SYSTEMS INC . AT 4040 TEXAS AVENUE , SOUTH STATE HIGHWAY 6 , COLLEGE STATION , TEXAS The above captioned facility will be located on the west side of State Highway 6 abutting on the frontage road between Graham Road and Birmingham Road . It will be adjacent to Winslow's Body Shop which is on Graham Road and Highway 6 frontage road. The only other facility in the area is a veterinary clinic on Graham Road adjacent to Winslow's Body Shop. Primary drainage for this area is the Navasota River. This river is fed by Rock Creek, the secondary system which lies one tenth mile to the south of the Saturn Gas System Inc . site . Drainage in the immediate vicinity is southerly across the ground surface which slopes toward Rock Creek. Much of the drainage from the site and the immediate area flows naturally into the highway system and is carried to Rock Creek. There are no surrounding developments other than the body shop and the veterinary clinic mentioned earlier. The development area is 0.53 acres , more or less.and being a part of that 3.0 acre tract in the Robert Stevenson League in Brazos County, Texas, being the same land described in a deed from Roy W .Kelly et ux to Jack Winslow et ux dated March 6, 1972, and recorded in Volume 301 , page 787, of the Brazos County Deed Records , said 0 .53 acres being more particularly described as follows: Beginning at the north-most corner of said 3 .0 acre tract: Thence South 28 degrees 19 minutes East 150.0 feet, to a point in the Northeast line of said 3 .0 acre tract and the west right-of-way line of State Highway 6 ; ..... Thence South 44 degrees 39 minutes West 165.0 feet; Thence North 28 degrees 19 m inutes West 150.0 feet to a point in the Northwest l ine of said 3.0 acre tract; Thence North 44 degrees 39 minutes East 165.0 feet to a PLACE OF BEGINNING and containing 0.53 acres of land , more or less . The area to be developed is presently covered with common pasture grasses , which will be disturbed only to the extent necessary to effect dev elopment. Since the area in question is so l imited in size , there are no primary or secondary drainage systems contained therein. The purpose of this development is to establish a strategically located compressed natural gas refueling facility in the South College Station area . At the location chosen , three ingredients of a good site are present: 1 .Abundant high-pressure natural gas from a line paralleling Graham Road . 2 .Electrical power as required . 3 . High density local and through traffic. Compressed natural gas(CNG) is deemed the best alternative fuel to gasoline and diesel fuels becquse it is the cleanest burning of the fuels mentioned . Also , the natural gas used will be domestically produced . According to the Flood Insurance Rate Map of Brazos County, Texas and Incorporated Areas, the development area is described as being outside the five hundred year flood plain. Only 5830 square feet of the area developed will be paved . A four inch rain on the paved area would cause less than 0.05 acre-feet of rapid run-off. This will be caused to flow off the paved area of the development into the highway drainage system at the southern end of the paved area. Drainage from the remainder of the 0.53 acre tract will not be altered appreciably from its present adequate state. Planned construction will not create constraints . Further, the adjacent property on the north side of the tract to be developed has had a considerable quantity of fill placed thereon which serves to divert runoff from higher ground to the north. This tends to alleviate the problem of drainage across the area of devlopment. There are presently no drianage problems associated with the area of development. Again , planned constuction will not result in constraints harmful to either the area of development or to adjacent properties. The burden on existing drainage facilities will not be changed. One culvert will be installed in the access from the developed site onto the Highway 6 frontage road. This will be of eighteen inch concrete-equal in capacity to the culvert under Graham Road. There will be no detention/retention storage or outlet works. CONCLUSIONS To the best of my knowledge, the following development plan is submitted in compliance with Standards of the City of College Station Drainage Policy and Design Standards. This development is located outside the 500 year flood plain and will pose no hazard or cause damage from stormwater flows. Respectfully Submitted, ~~~ Richard D. Mills Registered Professional Engineer State of Texas No. 16833 '~ .J w1 -.......... ; ............... ·-···-· .... I .., t,, ..J ..J oJ •t I 4 . : . -.... ---.... ~ .......... . ,, ·. Staie • ., p • ,,.. ·:~ "• ,,. ·' ;·:~ .... ~oard of R ~g}~irati~r -J?r !.'.;'~~ ~\>R ;w~k 1"8·;·29 Professiona l E11g ineers ' · .' /. AUST!N. TEXAS 7 8760 THIS CERTIFIES THAT WHOSE S IGNATUR E Af'PEARS BELO "'{, BEING THE HOLD E R OF CERTIFICATE NUMBER 16 8 3 3 CURRENTLY RENEWED IS ENTITLED TO PRACTICE AS A PROFESS IONAL EN GINEE R IN TE XAS FOR PERICO OF 07/01/94 -. 06130195 - "· ',',' :-:· ·.· . .. ... :·.·· ··;:· .; FINAL DRAINAGE REPORT OF SATURN GAS SYSTEMS, INC. AT 4040 TEXAS AVENUE, SOUTH STATE HIGHWAY 6 COLLEGE STATION, TEXAS The above captioned facility will be located on the west side of State Highway 6 abutting on the frontage road between Graham Road and Birmingham Road. It will be adjacent to Winslow's Body Shop which is on Graham Road and Highway 6 frontage road. The only other facility in the area is a veterinary clinic on Graham Road adjacent to Winslow's Body shop. Primary drainage for this area is the Navasota River. This river is fed by Lick Creek, the secondary system which lies two tenths mile to the south of the Saturn Gas System Inc. site. Drainage in the immediate vicinity is southerly across the ground surface which slopes toward Lick Creek. Much of the drainage from the site and the immediate area flows naturally into the highway system and is carried to Lick Creek. There are no surrounding developments other than the body shop and the veterinary clinic mentioned earlier. The development area is 0.53 acres, more or less, and being a part of that 3. 0 acre tract in the Robert Stevenson League in Brazos County, Texas, being the same land described in a deed from Roy W. Kelly et ux to Jack Winslow et ux dated March 6, 1972, and recorded in Volume 301, page 787, of the Brazos County Deed Records, said 0. 53 acres being more particularly described as follows: Beginning at the north-most corner of said 3.0 acre tract: Thence South 28 degrees 19 minutes East 150.0 feet, to a point in the Northeast line of said 3.0 acre tract and the west right-of-way line of State Highway 6; Thence South 44 degrees 39 minutes West 165.0 feet; Thence North 28 degrees 19 minutes West 150.0 feet to a point in the Northwest line of said 3.0 acre tract; Thence North 44 degrees 39 minutes East 165.0 feet to a PLACE OF BEGINNING and containing 0.53 acres of land, more or less. The area to be developed is presently covered with common pasture grasses, which will be disturbed only to the extent necessary to effect development. Since the area in question is so limited in size, there are no primary or secondary drainage systems contained therein. The purpose of this development is to establish a strategically located compressed natural gas refueling facility in the South College Station area. At the location chosen, three ingredients of a good site are present: 1. Abundant high-pressure natural gas from a line paralleling Graham Road. 2. Electrical power as required. 3. High density local and through traffic. Compressed natural gas (CNG) is deemed the best alternative fuel compared to gasoline and diesel fuels because it is the cleanest burning of the fuels mentioned. used will be domestically produced. Also, the natural gas According to the Flood Insurance Rate Map of Brazos County, Texas and Incorporated Areas, the development area is described as being outside the five hundred year flood plain. Only 5830 square feet of the area developed will be paved. A four inch rain on the paved area would cause less than 0.05 acre- feet of rapid run-off. This will be caused to flow off the paved area of the development into the highway drainage system at the southern end of the paved area. Drainage from the remainder of the 0.53 acre tract will not be altered appreciably from its present adequate state. Planned construction will not create constraints. Further, the adjacent property on the north side of the tract to be developed has had a considerable quantity of fill placed thereon which serves to divert runoff from higher ground to the north. This tends to alleviate the problem of drainage across the area of development. In addressing the influence of drainage from adjacent areas, run-off volumes anticipated both PRE-and POST-construction will be projected. Two areas are considered; the first lies to the north of the construction between Rock Prairie Road and Birmingham Road adjacent to SH 6, and the second lies fully within the Winslow property and includes the Saturn Site. They are designated as Area I and Area II, respectively. of 5 yr. , 10 yr. , 2 5 yr. , Calculations are made for the effects 50 yr., and 100 yr., storms are anticipated both prior to and after construction. The formula used for calculating run-off discharges is Q=CIA, where: Q = Discharge in cubic feet per second C = Run Off coefficient I Rainfall Intensity in inches per hour A Drainage area in acres Runoff coefficients C are taken from an ASCE table. Rainfall Intensity I is calculated from the formula I= b/(tc + d) raised to the e power where b, d and e are constants listed in the TEX-DOT Bridge Division Hydraulic Manual, Table 6. AREA I PRE: Constants: A= 19.2 ac; tc = 50 min; C = 0.10 POST: Constants: A= 19.2 ac; tc = 40 min; C = 0.20 PRE POST 5 yr. 6.02 13.98 10 yr. 6.89 15.89 25 yr. 7.95 18.31 50 yr. 9.07 20.87 100 yr. 9.45 21.67 NOTE: It is estimated that at least half of this runoff drops into the main State Highway 6 drainage by following the ON RAMP and by overflowing the curbs along the sides of the frontage road. This is considered in the later calculation of total runoff passing through the Graham Road culvert at SH 6. AREA II PRE: Constant: A= 1.6 ac; tc = 50; c = 0.10 POST: Constant: A= 1.6 ac; tc = 40; C = 0.20 PRE POST 5 yr. 0.58 1.17 10 yr. 0.66 1. 33 25 yr. 0.76 1. 52 50 yr. 0.87 1. 74 100 yr. 0.90 1. 80 NOTE: All of the above calculated volume through the Graham Road culvert. will pass The maximum volume expected to enter the drainage ditch on the frontage road side of the Saturn site is as follows: AREA 1 Runoff /2 + Area II Runoff (21.67 I 2) + 1.80 = 12.63 c fp s This is also the maximum flow expected throught the culvert at Graham Road and SH 6. The capacity of the culvert at Graham Road and SH 6 is determined as follows: Culvert is dual 18 inch x 24 feet. Assumed time of flow through culvert: 5 seconds v = 3.1416 x (9/12 x 9/12) x 24 x 2/5 3.146 x 0.5625 x 24 x 2/5 = 84.8 cu. ft./ 5 = 16.9 6 c ub i c feet per second • This value is well above the calculated maximum runoff to be handled by the culvert in question. An Inspection of the area in this immediate vicitnity following the flood rains of October, 1994 confi r med that this culvert adequatedly handled the runoff coming through it. There are presently no drainage problems associated with the area of development. Again, planned construction will not result in constraints harmful to either the area of development or to adjacent properties. The burden on existing drainage facilities will not be changed. The same culvert as at Graham Road and SH 6 is planned and should be adequate at that point even after the surrounding area has developed. There will be no detention/retention storage or outlet works. CONCLUSIONS To the best of my knowledge, the development plan is submitted in complaince with Standards of the City of College Station Drainage Policy and Design Standards. This development is located outside the 500 year floodplain and will pose no hazard or cause any damage from stormwater flows. Respectfully Submitted, ~?V;h~ Richard D. Mills, P.E. State of Texas No. 16833