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Home My WebLink AboutDevelopment PermitSCHULTZ ENGINEERING, LLC. 2730 Longmire Drive, Suite A College Station, Texas 77845 Firm No. 12327 Castlegate II Community Center Public Sidewalk Construction Engineer's Estimate of Construction Item Description Unit Estimated uanti Unit Price Total General Items I Mobilization, Overhead and Construction Staking LS I l $ 500.00 $ 500.00 General Items Subtotall $ 500.00 Public Sidewalk 2 Demolish & Remove Existing Concrete Sidewalk, complete in place SF 526 $ 2.00 $ 1,052.00 3 Concrete Sidewalk, complete in place SF 140 $ 4.50 $ 630.00 4 ADA Ramps - Detectable Warning Surfaces, complete in place EA 4 $ 600.00 $ 2,400.00 Public Sidewalk Items Subtotal $ 4,082.00 TOTAL CONSTRUCTION1 $ 4,582.00 SCHULTZ ENGINEERING. LLC. Page 1 of 1 SCHULTZ ENGINEERING, LLC. 2730 Longmire Drive, Suite A College Station, Texas 77845 Firm No. 12327 Castlegate II Community Center Public Sidewalk Construction Engineer's Estimate of Construction Item Description Unit Estimated Quantity Unit Price Total General Items 1 Mobilization, Overhead and Construction Staking LS 1 $ 500.00 $ 500.00 General Items Subtotal $ 500.00 Public Sidewalk 2 Demolish & Remove Existing Concrete Sidewalk, complete in place SF 526 $ 2.00 $ 1,052.00 3 Concrete Sidewalk, complete in place SF 140 $ 4.50 $ 630.00 4 ADA Ramps - Detectable Warning Surfaces, complete in place EA 4 $ 600.00 $ 2,400.00 Public Sidewalk Items Subtotal $ 4,082.00 TOTAL CONSTRUCTION $ 4,582.00 r -,".f SCHULTZ ENGINEERING, LLC. Page 1 of 1 7,15 SCHULTZ ENGINEERING, LLC. 2730 Longmire Drive, Suite A College Station, Texas 77845 Firm No. 12327 Castlegate II Community Center Public Sidewalk Construction Engineer's Estimate of Construction Item Description Unit Estimated Quantity Unit Price Total General Items 1 Mobilization, Overhead and Construction Staking LS 1 1 $ 500.00 $ 500.00 General Items Subtotal $ 500.00 Public Sidewalk 2 Demolish & Remove Existing Concrete Sidewalk, complete in place SF 526 $ 2.00 $ 1,052.00 3 Concrete Sidewalk, complete in place SF 140 $ 4.50 $ 630.00 4 ADA Ramps - Detectable Warning Surfaces, complete in place EA 4 $ 600.00 $ 2,400.00 Public Sidewalk Items Subtotal $ 41082.00 TOTAL CONSTRUCTION $ 4,582.00 r-ICq<T SCHULTZ ENGINEERING, LLC. Page 1 of 1 7,15 10 U 20 SCALE IN FEET Af A c0xa¢ie .,Axro PLI V b E O 3R 7, eoeTtOumP a 6• SIDE WALLSi su-rrne.l-e AREA INL r 11.1 LEGEND GRAVEL BAC � GRAVEL BA NDTE: TEMPORARY DEVICES AROUND STORM DRAINS ARE USED i DETAIN AND/OR EI H E )HFUER SEDIMENT -LADEN RUNOFF. THE PROTECTIONSHALLOWS SEDIMENT MENT TO SETTLE PRIOR TO DISCHARGE INTO A STORM DRAIN INLET OF CATCH BASiN, GRAVEL BAGS SHALL BE UV RESISTANT AND MUST NOT DEGRADE DUE TO ATMOSPHERIC CONDITIONS. GRAVEL BAGS SHALL REPLACED UPON PSIGN OF DETERIORATION. GRAVEL BAGS SHALL BE INSTALLED k MONITORED THROUGHOUT THE PROJECT UPON INSTALLATION OF AN INLET. , GRAVEL BAGS TO BE FILLED WITH CLEAN 3/4' OR LESS GRAVEL. STORM DRAIN INLET PROTECTION N:1'.S As�OA®6 Avutr 9LT R%£ AAn/OR � 74 ax xArwul w i rF D oPEc w 4 xt Yd. Da.a 4 I .. •. t SILT rENCE ASSEMBLY ( a Cl.OI—E AsiOtte) uvER 3 SAVE sW� E 60' iO I" FOOTALE n0.E.3xAna 5TGNE IS o ecEu' n MucnwFROM iv`iR FAee�c FROAc£Ri RIIG W siaEErs. •"v'Yzs ic6c a aix ceL CONSTRUCTION EXIT SILT CONTROL N.T.S ,. K oolPTn�a Iles! aaxGa ]iff�u.V[e�w OM oFxviY%s oc r n M ewmwn P�Clae Tm As] oe0) ae)�nr n�[nsnnF oox,Drt nau menu uas],aF wmwr ro 4x xewc na oPranni IUKnwl nE sraEr mcxra-ur 9vz1 s mPACEa ro ass o£ ME Rwmnnl mr DD,sm. L THE-- ME CONC(Ert SFffL4X$ SWLL BE CdnACiEO A. 'PFtlOF-RC1IE0'. NA' arAY OR SOFT AWT WR[ED B! ME'P0.JnF-RMIxG' S,WL BE 0.ElD5TD HA RFPIM 1 HV[KM 0.46+ $IIFQ SiW1 SOi OL® 1Y.IM a i5E roPOGRIAlr 90x1 K iA)11 fELD SIaM1EY GTA PPFPNYD. 0. SIRLCINiLL BAWEL (tn UNIF! OR Srpx DAbi tRIXUEs K REOUFYD a1GFfR THE iPFHEH IS x1rRw e' OF PAflfOR nR'SIC— TIC mOw>m+c iLNtS. 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K R6NIISHE fM BrsPL<INO AND W81IAxP0 TRY [AOSWi A'0 SEpSYM Cttf11gL Ofl%FS IM5 9W1 I%MC fl4Rf ,4 ax NO MER flFA/ WNFNL E\4Rr CP ,/z• qi ME WHIPIerPi PdT£ ILL Yt0 [OV9rw ON THE Mi:![NT SrFSEK AS A aF61Ai F THE COWT—I YLRE OF 116 PRhffCi. a CMEtt6'ILPCIplIOSRfIErsSR£ i0 YMTAn ME TiD6 0E]iF➢!1. PERIar W. 1>R 160000 RFDwtEYEN15 FOR a ME canwcroa 95YL T6xoc ME rRo90x mllnaal 5[ASLss aHtt puts K mramlm. a 6aE] MOlEC11Ct1 ro 6E x59UID AT ALL P ILO EainxO Nkte AQSYAT TO THE PROECr SRE VICINITY MAP Schultz Engineering, LLC THE SEAL NT APPEARING ON D ISB DOCUMENT WAS AUTHORIZED tT' JOSEPH P. S P.E. LICENSE 2730 Longmire, s9keA ON MA, N0. 65889 ON MARCH 27, 2013. college station, Texas77845 -979.764.3900 TOPE N0.12327 ISSUED FOR REVIEW SURVEYED DESIGNED DRAIVN A"' OVED JOBNO. DAIS KERR JPS JKO JPS 12-220 MARCH 2013 As�OA®6 Avutr 9LT R%£ AAn/OR � 74 ax xArwul w i rF D oPEc w 4 xt Yd. Da.a 4 I .. •. t SILT rENCE ASSEMBLY ( a Cl.OI—E AsiOtte) uvER 3 SAVE sW� E 60' iO I" FOOTALE n0.E.3xAna 5TGNE IS o ecEu' n MucnwFROM iv`iR FAee�c FROAc£Ri RIIG W siaEErs. •"v'Yzs ic6c a aix ceL CONSTRUCTION EXIT SILT CONTROL N.T.S ,. K oolPTn�a Iles! aaxGa ]iff�u.V[e�w OM oFxviY%s oc r n M ewmwn P�Clae Tm As] oe0) ae)�nr n�[nsnnF oox,Drt nau menu uas],aF wmwr ro 4x xewc na oPranni IUKnwl nE sraEr mcxra-ur 9vz1 s mPACEa ro ass o£ ME Rwmnnl mr DD,sm. L THE-- ME CONC(Ert SFffL4X$ SWLL BE CdnACiEO A. 'PFtlOF-RC1IE0'. NA' arAY OR SOFT AWT WR[ED B! ME'P0.JnF-RMIxG' S,WL BE 0.ElD5TD HA RFPIM 1 HV[KM 0.46+ $IIFQ SiW1 SOi OL® 1Y.IM a i5E roPOGRIAlr 90x1 K iA)11 fELD SIaM1EY GTA PPFPNYD. 0. SIRLCINiLL BAWEL (tn UNIF! OR Srpx DAbi tRIXUEs K REOUFYD a1GFfR THE iPFHEH IS x1rRw e' OF PAflfOR nR'SIC— TIC mOw>m+c iLNtS. WM AMKM](R ro ilff ACR -L M `—CD CONIGW WMELFII 9pxi A9E MPA0.x4£ldFxE E IXaY M `—N I—E � ¢�EYAlg1K pUDt fDR CONSIR101KK1 OF ME SRE xXi1L ]. u]IF ro Pavmrt rvN POA waelmrt oxKravcTDRI BLnns xm xoT¢ l ME CIXtIF/CTOR 9W1 aaYA3( NL TOPaOa Aho TrtPI/cE rt OH ALL OKtURLfO IRFAS ALL PARI[0 wf 19AAD5 /AFA MY[Exf W PI.�G Ab SOEw41( RYAS SWIt RECO,E 6' Waf IAW tnPSpL PpM ro ftIGFT¢ltf OF OMs3 600 OR HM1nONAfiL 0. Svvl[3 M UIV+V!' PaMO S151DK tO�RgIIE�erdNrA]FR�AIGAD AW Hlr tl@id%N' USES xIERLTTfIXt to ]Iff eEtFti FEL Pb SHALL HOT IXIDO Bc1Ddb M FA[E Di ME [IIDxO lOIRG110lL ,L 1K IPPiY P0Rn051 tK ALL BMT IXGW501K 9fGRD % BACIYTrm YRM ppA+£FLY <OlPrelm CUT 5063 t0 THE t[l1PAlxx C•f SIF[ACE YAIE0. A CIAY ilW' 9gLlD BE PRT^DFD x ME 51n00..dE� Mit�ff F sIRIF:1MEWd MMOHUC FXNOr TM FE£T BETb® a 14 IN41—TCIOMEHS, TRxF maatzmgs I . ALL W— 91416E a4vAGE0 AM SN—E0 i[R NNSE i [A]0ll ALL PROPo9D PA¢ wT t4A103 xM FULL —TH TOPSOL SrCP9 SD1FA KE T As 9VIL 6£ ROPE 51x-33. AStY t J0.H9 PPE MAY Y USED M FVtE Cf — KG LOPE AAOHro -zat. 1tPE TIXM1I S.LL W1EE51111 r�PRnPdfD 6itlx YrfA K PRVAIE AIO 31V11 BE IN3TADID N AttxAnA <[ MM LCUL g1AVbiO LWiPA01Ms9W1 Mix Y LOCAL elAOx'0 ORKOLs ]IMEE iFI6A16 flEGF TH BT ME tltt ttawFE aTAMx1 1WM 10 COWtI6R6101pN DF ME STORY 5£xx l RYA PAER WT BE Gst x PLACE OR PRECAet AVE Aic Ys-wwwlwREs9�cs�c s�ur�c�aF 3wo Psi �"� a—ANDRAL BAQ6HL I.Ws AK t%iRYD As AMT iPE]Itll 9:CTAY 12ap1 0R x]1@1 a' 0f PA\Flmrt. mlmFucTR6RI RnT¢ ,. TSE w6racrw n.•: � A[SPoM.'9tE FDR SIRP,na Tiff Quer we zrel a Au DaTPw umucPnw Pram¢ 6DMG10N a TIE ulalrc cowuaF_s 4e Ions x Anaxx a wKiRllclml rs RmzRm. 6n TEss eao) us -am ARFFns u+ER6 : n4-ssos StCODi l!e( N16R6aCx1xNS 0a Sa3-2420 s sat. wv ez,-nw 2 [ K THE CttRWLTgt ro VSE [MTMF IS 5 IECESS4Yf TO I@56ZE FFOSOR NO PF£9if �Y➢eE6R FRO- tE6N] THE FR0.4et 9TE 1H5 BiL10Ee ME NsfNUiOH OF A WNsiPo1Ci1 A pvr ASID Rr FOKF IFCF3StAY. 1 ME Obit T. K R6NIISHE fM BrsPL<INO AND W81IAxP0 TRY [AOSWi A'0 SEpSYM Cttf11gL Ofl%FS IM5 9W1 I%MC fl4Rf ,4 ax NO MER flFA/ WNFNL E\4Rr CP ,/z• qi ME WHIPIerPi PdT£ ILL Yt0 [OV9rw ON THE Mi:![NT SrFSEK AS A aF61Ai F THE COWT—I YLRE OF 116 PRhffCi. a CMEtt6'ILPCIplIOSRfIErsSR£ i0 YMTAn ME TiD6 0E]iF➢!1. PERIar W. 1>R 160000 RFDwtEYEN15 FOR a ME canwcroa 95YL T6xoc ME rRo90x mllnaal 5[ASLss aHtt puts K mramlm. a 6aE] MOlEC11Ct1 ro 6E x59UID AT ALL P ILO EainxO Nkte AQSYAT TO THE PROECr SRE VICINITY MAP CASTLEGATE II GRADING, DRAINAGE, &TIG�SCALE A SHEET 1 x../..................1`r. „.P;.n COMMUNITY CENTER �� 6 NORWICH DRIVE EROSION & SEDIMENT HORIZONTAL 1•=20' COMMON AREA —CASTLEGATE II SUBDIVISION CONTROL PLAN PLOTTING SCALE: 1:1 FIRM 111 i232 SCHULR ENGINEEPoNO, NG, LED LLC SECTION 200, COLLEGE STATION rTLENa.Ie 12-220 „Hr aye, .�• . L l'e 1 t► -c► •"nye.µ-`'��•I i�I11rp I CASTLEGATE II GRADING, DRAINAGE, &TIG�SCALE A SHEET 1 x../..................1`r. „.P;.n COMMUNITY CENTER �� 6 NORWICH DRIVE EROSION & SEDIMENT HORIZONTAL 1•=20' COMMON AREA —CASTLEGATE II SUBDIVISION CONTROL PLAN PLOTTING SCALE: 1:1 FIRM 111 i232 SCHULR ENGINEEPoNO, NG, LED LLC SECTION 200, COLLEGE STATION rTLENa.Ie 12-220 Schultz Engineering, LLC Office: 979.764.3900 Fax: 979.764.3910 March 29, 2013 Alan Gibbs, P.E. City Engineer Development Services City of College Station College Station, Texas RE: Letter Aeknowledging City Standards — Castlegate II Community Center Dear Mr. Gibbs: The purpose of this letter is to acknowledge that the construction plans for the public sidewalk improvements for the above -referenced project, to the best of my knowledge, do not deviate from the B/CS Design Guideline Manual. I also acknowledge that, to the best of my knowledge, the details provided in the construction plans are in accordance with the B/CS Standard Details. Sincerely, Jr seph P. Schultz, P.E. Civil Engineer / gV, OF ' *J' . .a%.j .i.#..,..........i11t.....** ith JOSEPH P. SCHULIZ 865889 F-12327 SCHULTZ ENGINEERING, LLC, P.O. Box 11995 • College Station, Texas 77842 schultzengineeringllc.com March 29, 2013 Danielle Singh, P.E. Civil Engineer City of College Station 1101 Texas Avenue College Station, Texas 77840 Re: Castlegate II Community Center (SP) — 13-00900034 Pond A Drainage Report Letter Dear Ms. Singh: 4Schultz Engineering, LLC Office: 979.764.3900 Fax: 979.764.3910 This project results in minor decreases in Pond A volume (decreases shown below), which have a minor impact on the pond outflow and no increase in pond water surface elevation. A revised HEC - HMS Analysis was performed on the system using the decreased volumes resulting in a 0.6 cfs increase in the pond outflow and no increase in the Pond A 100 -year water surface elevation (311.70') for a fully functioning outfall or (314.70') for a blocked outfall. There are no negative effects of the minor filling of the pond area on the adjacent properties. Refer to Appendix A for the previous As -built Report for Pond A. Elevation Decrease in Volume FT AC -FT 308.5 0 309.00 0.0043 310.00 0.0261 311.00 0.0609 312.00 0.1068 314.00 0.1413 314.50 0.1443 315.00 0.1473 If you have any questions, please do not hesitate to call. Sincerely, Schultz Engineering, LLC. �k" JoPm chultz, P.E. Mger/Civil Engineer 1 1 &iJLT' SCHULIZ ENG(NEERIN0, LLC. P.O. Box 11995 • College Station, Texas 77842 schultzengineeringllc.com _(3 Appendix A Addendum #1 for Detention System Report Castlegate H Subdivision, Section 200 College Station, Texas Reflecting As -built Conditions Following Construction ADDENDUM #1 FOR DETENTION SYSTEM REPORT CASTLEGATE II SUBDIVISION, SECTION 200 COLLEGE STATION, TEXAS Reflecting As Built Conditions following Construction OCTOBER 2011 Prepared by: Phillips Engineering 4490 Castlegate Drive College Station, Texas 77845 (979) 690-3141 TBPE Firm #13130 �P-es OF Jr� ADDENDUM #1 Revisions to Drainage Model resulting from In -the -Field Modifications During the construction phase of Section 200 in Castlegate II, three significant modifications were made to the detention system design that had potential for changing the results predicted by the HEC -HMS computer model previously described in the Drainage Report. These modifications were input into the model and re- analyzed to determine what effect they had on the system. The three changes made to the design were: Increase in the size of Detention Pond A — Following discussions with the city staff, it was determined that the existing FEMA Floodplain lines had strong impacts on the ability to develop the land adjoining the original pond boundaries. To address this situation and facilitate future development of the property, the southeastern boundary of the detention pond and its corresponding Common Area Boundary was moved outward to the existing FEMA Floodplain line. The northwest boundary of the pond adjacent to the city park property was not changed. The resulting pond is approximately 0.40 acres larger than the original at elevation 312.0. This increased size produces an additional 1.42 ac -ft of storage or about 15% more than the original pond design. The change in shape also required one of the inflow pipes to be rerouted to align with future lot lines planned in the area adjacent to the pond. 2. The shape of the outlet control structure on the existing pond in Castlegate was modified from a step weir configuration to a straight wall configuration — This modification was necessary as a result of in - the -field constraints that were not accounted for in the original design. Reduced excavation downstream of WS Phillips Parkway — The area immediately downstream of WS Phillips Parkway was originally planned for excavation in order to increase storage capacity available during peak flow periods. As construction neared completion, it became evident the additional excavation was not needed due to the pond enlargement described in #1 above. The area was cleared and shaped, but no significant excavation was performed except around the flume connecting the box culverts on WS Phillips with the existing pool in Castlegate. Summary of Results The Post -development flowrates were re -analyzed at the same point immediately downstream of the outlet control structure of the existing detention pond near Castlegate Drive. The revised results are shown below: Location Study Pt A2 Castlegate Drive (original design results) Pre-Dev Post Dev 448.8 cfs 448.8 cfs 383.8 cfs 405.3 cfs Max. WSEL — Mod. Castlegate Pond (peak 100 yr) Max. WSEL — Mod. Castlegate Pond (blocked) Top of Berm — Mod. Castlegate Pond Max. WSEL — Pond A (peak 100 yr) Max. WSEL — Pond A (blocked) Low Pt of WS Phillips Pkwy Reduction 65.0 cfs 43.5 cfs As -Built Or_ iginal = 309.30 309.10 = 309.80 309.80 = 310.50 310.50 311.70 311.70 314.70 * 314.70 314.03 314.03 As demonstrated above, the three modifications made over the course of the construction project show a slight decrease in the peak flowrate released from the original design and a slight increase in the WSEL of the Castlegate Pond. The new WSEL is still more than 1 foot below the Top of Berm level in the pond as required by the BCS Design Guidelines. From these results we conclude that no adverse effects will result from the three as -built modifications described above. March 29, 2013 Danielle Singh, P.E. Civil Engineer City of College Station 1101 Texas Avenue College Station, Texas 77840 Re: Castlegate II Community Center (SP) —13-00900034 Pond A Drainage Report Letter Dear Ms. Singh: Schultz Engineering, LLC Office: 979.764.3900 Fax: 979.764.3910 This project results in minor decreases in Pond A volume (decreases shown below), which have a minor impact on the pond outflow and no increase in pond water surface elevation. A revised HEC - HMS Analysis was performed on the system using the decreased volumes resulting in a 0.6 cfs increase in the pond outflow and no increase in the Pond A 100 -year water surface elevation (311.70') for a fully functioning outfall or (314.70') for a blocked outfall. There are no negative effects of the minor filling of the pond area on the adjacent properties. Refer to Appendix A for the previous As -built Report for Pond A. Elevation Decrease in Volume FT AC -FT 308.5 0 309.00 0.0043 310.00 0.0261 311.00 0.0609 312.00 0.1068 314.00 0.1413 314.50 0.1443 315.00 0.1473 If you have any questions, please do not hesitate to call. Sincerely, Schultz Engineering, LLC. Jo kl--L- , P.E. M' nager/Civil Engineer I IAOff SCHULTZ ENGINEERING, LLG, P.O. Box 11995 - College Station, Texas 77842 schultzengineeringllc.com _t3 Appendix A Addendum #1 for Detention System Report Castlegate II Subdivision, Section 200 College Station, Texas Reflecting As -built Conditions Following Construction ADDENDUM #1 FOR DETENTION SYSTEM REPORT CASTLEGATE II SUBDIVISION, SECTION 200 COLLEGE STATION, TEXAS Reflecting As Built Conditions following Construction OCTOBER 2011 Prepared by.- Phillips y:Phillips Engineering 4490 Castlegate Drive College Station, Texas 77845 (979) 690-3141 TBPE Firm #13130 ADDENDUM #1 Revisions to Drainage Model resulting from In -the -Field Modifications During the construction phase of Section 200 in Castlegate II, three significant modifications were made to the detention system design that had potential for changing the results predicted by the HEC -HMS computer model previously described in the Drainage Report. These modifications were input into the model and re- analyzed to determine what effect they had on the system. The three changes made to the design were: Increase in the size of Detention Pond A — Following discussions with the city staff, it was determined that the existing FEMA Floodplain lines had strong impacts on the ability to develop the land adjoining the original pond boundaries. To address this situation and facilitate future development of the property, the southeastern boundary of the detention pond and its corresponding Common Area Boundary was moved outward to the existing FEMA Floodplain line. The northwest boundary of the pond adjacent to the city park property was not changed. The resulting pond is approximately 0.40 acres larger than the original at elevation 312.0. This increased size produces an additional 1.42 ac -ft of storage or about 15% more than the original pond design. The change in shape also required one of the inflow pipes to be rerouted to align with future lot lines planned in the area adjacent to the pond. 2. The shape of the outlet control structure on the existing pond in Castlegate was modified from a stet, weir confleuration to a straight wall configuration — This modification was necessary as a result of in - the -field constraints that were not accounted for in the original design. Reduced excavation downstream of WS Phillips Parkway — The area immediately downstream of WS Phillips Parkway was originally planned for excavation in order to increase storage capacity available during peak flow periods. As construction neared completion, it became evident the additional excavation was not needed due to the pond enlargement described in #1 above. The area was cleared and shaped, but no significant excavation was performed except around the flume connecting the box culverts on WS Phillips with the existing pool in Castlegate. Summary of Results The Post -development flowrates were re -analyzed at the same point immediately downstream of the outlet control structure of the existing detention pond near Castlegate Drive. The revised results are shown below: Location Pre-Dev Post Dev Reduction Study Pt A2 Castlegate Drive 448.8 cfs (original design results) 448.8 cfs Max. WSEL — Mod. Castlegate Pond (peak 100 yr) Max. WSEL — Mod. Castlegate Pond (blocked) Top of Berm — Mod. Castlegate Pond Max. WSEL — Pond A (peak 100 yr) Max. WSEL — Pond A (blocked) Low Pt of WS Phillips Pkwy 383.8 cfs 65.0 cfs 405.3 cfs 43.5 cfs As -Built Ori = 309.30 309.10 = 309.80 309.80 = 310.50 310.50 = 311.70 311.70 = 314.70 * 314.70 = 314.03 314.03 As demonstrated above, the three modifications made over the course of the construction project show a slight decrease in the peak flowrate released from the original design and a slight increase in the WSEL of the Castlegate Pond. The new WSEL is still more than 1 foot below the Top of Berm level in the pond as required by the BCS Design Guidelines. From these results we conclude that no adverse effects will result from the three as -built modifications described above. FLOODPLAIN FILL REPORT FOR CASTLEGATE II COMMUNITY CENTER COLLEGE STATION, TEXAS March 2013 Prepay_ ed By k tz Engineering, LLC TBPE Firm No. 12327 P.O. Box 11995 College Station, TX 77842 2730 Longmire Drive, Suite A College Station, Texas 77845 (979) 764-3900 The proposed Community Center site is located in an area designated as a Special Flood Hazard Zone. The site was previously filled, and this project will require a small amount of additional fill material placement. The previously placed fill was accounted for in the as -built certification and analysis of the detention pond. The additional fill material for the Community Center will result in a slight decrease in the volume of the pond. The decreased storage volume in the pond was input into the HEC -HMS Model, and the result was a slight increase in the pond outflow, 0.6 cfs, but no rise in the pond water surface elevation. The purpose of this report is to address Chapter 13 - Flood Hazard Protection, Section 13-5 — Special Provisions, E — Special provisions for areas of special flood hazard, I I(a)(1): a) An increase in the base flood elevations. In the event that base flood elevations are not known at the time of submitting the information required herein, base flood elevations must be determined; The base flood elevations (BITE) for the special flood hazard area ranged from 313.5 to 317.4 prior to the placement of fill. A storm sewer system was constructed in this area with Section 201. In accordance with the Drainage System Report for Castlegate II Subdivision, Section 201— Revised February 2010, prepared by Phillips Engineering, the hydraulic grade line (HGL) in the storm sewer piping ranged from 313.3 to 314.8 which is lower than the BFE. b) Creation of additional areas of special flood hazard area; The base flood elevation did not increase, therefore there was no creation of special flood hazard area. c) A loss of conveyance capacity to that part of the special flood hazard area that is not in the floodway and where the velocity of flow in the base flood event is greater than one (1) foot per second. This area can also be approximated to be either areas within one hundred (100) feet of the boundary of the regulatory floodway or areas where the depth of from the BFE to natural ground is eighteen (18) inches or greater; The storm sewer system designed and constructed with Section 201 passes the 100 - year flow in the pipes so adequate conveyance has been provided. There is no loss of conveyance. d) A loss of base flood water storage volume to the part of the special flood hazard area that is beyond the floodway and conveyance area where the velocity of flow in the base flood is equal to and less than one (1) foot per second without acceptable compensation as set forth herein. Acceptable compensation for the loss of storage volume requires a demonstration of cuts and fills, must be mitigated on-site and must demonstrate no net fill. In general, excavation within the special flood hazard area and below the base flood elevation is the only acceptable method of mitigation of fill placed below the base flood elevation in the special flood hazard area; The loss of base flood water volume was compensated by the construction of the adjacent stormwater detention pond which created additional storage volume to the natural condition and resulted in a lowering of the 100 year stormwater surface elevation. e) An increase in base flood velocities. In the event the future conditions flood data is known at the time of submittal, then the future conditions modeling must be used in lieu of the base flood modeling. The existing channel has been filled, and the velocities in the storm sewer pipe are at acceptable levels. The flows in the pipes are based on future conditions. 5CHULTZ ENGINEERING, LLC. 21.13