The URL can be used to link to this page

Home My WebLink AboutDrainage Reports - 10/26/2011M City of 1=t. CoMnis prov d Plans Approved By so.. Date_Y! September 22, 2011 Wes Lamarque, Stormwater Engineer Fort Collins Utilities 700 Wood Street Fort Collins RE: Early Childhood Development Center (CSU Washington School) NA PN: 1843c Dear Wes: JVA, Incorporated 25 Old Town Square Suite 200 Fort Collins, CO 80524 Ph: 970.225.9099 Fax: 970.225.6923 Toll Free: 877.444.1951 Web site: www.jvajva.com E-mail: info@jvajva.com This letter is prepared to summarize the changes in impervious area associated with the site improvements for the renovations of the Washington School to an Early Childhood Development Center by CSU. Washington School is located at the northwest corner of Shields Street and Olive Street and was previously owned by the Poudre School District. Colorado State University has recently purchased the school and is renovating the building to be an Early Childhood Development Center. As part of the renovation, and bringing the building up to applicable codes, and network of accessible ramps are proposed. In addition to the proposed site ramps, the remaining site improvements will mainly consist of paving of the north parking area, and paving the existing alley to the north. To accommodate the proposed improvements, the existing gravel parking area will be either paved or adjusted to landscape area, and the existing asphalt basketball court will be removed. Based on information conveyed to me by CSU, the site is located within the Old Town Drainage Basin. It was mentioned that redevelopment/infill projects are allowed an increase of 5,000 square feet (sf) of impervious area before onsite detention is required. The weighted historic and developed percent impervious was calculated, with the measured square footage included (the spreadsheet pdf is attached). With the removal of the basketball court asphalt and removal the existing parking gravel area, there is a slight decrease in percent impervious. There is an increase in pavement area and walks of 4,749 sf, a reduction of 13,574 sf gravel parking area, and an increase in lawn area of 8,825 sf. The playground area is currently gravel and analyzed with the impervious value accordingly. With the proposed removals and improvements, there is a total decrease in impervious area, or increase in pervious (landscape) area, of 8,825 sf. The proposed alley paving is not included within the onsite impervious calculations. An attempt was made to provide some water quality for the runoff leaving the alley. The drainage pan along the south edge of the alley directs runoff through the eastern parking area to a grass lined swale, then through a sidewalk chase which daylights into Shields Street. Also attached is a reduced copy of the proposed grading plan for reference. BOULDER I FORT COLLINS I WINTER PARK Based on the included information, the proposed improvements and adjusted impervious areas fall under the allowed increases within the Old Town Drainage Basin. Please feel free to contact me to discuss and questions you may have. Sincerely, NA, INCORPORATED Enclosure: CC: Architecture Plus CSU Facilities BOULDER I FORT COLLINS I WINTER PARK JVA, Incorporated 25 Old Town Square Suite 200 Fort Collins, CO 80524 Ph: 970.225.9099 Fax: 970.225.6923 CSU Washington School - Early Childhood Development Center IMPERVIOUS AREA CALCULATION/COMPARISON Design Engineer: J.Claeys Project Number: 1843c Date: September 23, 2011 DESIGN CRITERIA: Urban Storm Drainage Criteria Manual by Urban Drainage and Flood Control District, June 2001 City of Fort Collins - Storm Water Criteria Manual (1997) BASINS: % Impervious values from Table RC-3 in the Urban Storm Drainage Criteria Manual Runoff Coefficients and Frequency Adjustment Factors for City of Fort Collins - Storm Water Criteria Manual Land Use % Impervious Roof 90% Paved 100% Compacted Gravel 40% Drives & Walks 90% Lawns (Heavy, 2-7% Slope) 2% Sub -basin Designation otal s . ft ^roof s .ft ^paved s .ft ^gravel s .ft wa ^lk s .ft A,,., s .ft Weighted % Impervious Historic 76,073 9,460 6,154 27,490 5,533 27,436 41.0% Proposed 76,073 9,460 7,045 13,916 9,391 36,261 39.8% Hist vs. Prop - - 891 (13,574) 3,858 8,825. -1.2% Page 1 of 1 JVA, Inc. 2557 R I MATCH EXIST CONIC CROSSPA4 TC ' 2560 R� f MATCH EXIST CONIC CROSSPAN 2570 F. ME-' I I 7 I GRAVEL SOCKSEEK MATCH EXIST GRADES VEHICLE HEAD CONTROL EXIT EGA 5026 70 2592 ME 41 2525 ME 2569 4E 1 2541 ME ME 2556 ME -25.9 ME � i-25 b➢ R 25b7 R_ _�'.�, 2616 2539 ME 2515 - - 246} YE 2d 56 4E }IS Y' 26119 2 25 % 11II 24 4 2532 �2s T2 1+. `1479 FL 4-1 25.73 - - 25 - 2516 150J' 24B0 2457 2446 _ _ -- \SCL 2575E .SbI FL iWWST0N T025b1 2- CROWN (WEST) - C25.65 502 \ CONTROL 2PW! - 25.] 2573 f]-- 25J6 25.121 t GRAVFI SOON 256} 25A7 _2 2Z CROSS SLOE TOWARD S REEI DRY' WELL (SEE UTILITY PLAN N ARCH SET) MET)2594 ME25/N K kDWWELLY2528 EXIST CONIC5PAIJ i0 REMAIN526fi01'— n 1.,, 7 2555 ME 2fi �`� -- - `251k 4E - K SEDIMENT CONTROL((tIG `A �IYN 482 `2471 2495 2623 WE 26,12 7537 16 19 ME 25ZI ME PNIPS, LANDINGS :'.;'F" __ W STAIRS (RE ARCH) _ (TYP) EXIST CONC WALK TO REMAIN -- DEST CONC WAIN TO REMAIN RECONSTRUCT YE EXIST CONIC WALK mI!- -IAhiEL MrvE i !9 ME I 32)' I(- - YE / Y I ♦ II I � 0 L . 23J7 6" EROSION I A CONTROL ELANKET CB AT GRASS LINED ]1 R CN/NNEL (NAG C]50) O SC1 -2256 )5 N 22.d6 IiE REMOVE ANC REPLACE I I li i FENCE FOR LK CHASE OE I A 9DEW'ALN SS /5 NECESSARY I 1 1 9 LF 24' WIDE I I `. SIDEWALK CHASE I I I L I F I 4 W I I f X 1 ; I �I I f I • 8' €R F 666666� R � �P l� H� 8 EROSION CONTROL LEGEND ie a-i INLET PROTECTION `tJ YTC VEHKAE TRACKING CONTROL ®,R CURB ROCK SOCKS J � SCL ® SEDIMENT CONTROL LOG ® EROSION CONTROL BLANKET F Z Z O I O M 0Z l IL b R Z_ O I LL2 Of �Z CO N9 KC UU 20 0 20 W II ' I 7I SCARE IN FEET I I yAth 111tJYd 1 i I. EKSONG UTILITY IDCATIONS ARE APPROXIMATE AND DEPTHS ARE NOT 1 1 KNOWN. CONTRACTOR SHALL VERIFY DEPTH AND LOCATION OF ALL MUFFS 0 PROPOSED CONNECTIONS AND CROSSINGS PRIOR TO "WY t j I CONSTRUCTION. 2. REFERENCE L RIMER COERM URBN1 AREA STREET STANDARDS CHAPTER 25, FIGURES 25-1 TO 25-4. FOR PADDING; STMAWOS. 3. CONTRACTOR S RESPON9BLE FOR ALL SURFACE REPAIR/REPLACEMENT TO RESTORE SIDEWALKS. ASPHALT. CUT d: ,I GUTTER SECTIONS AND SOO AREAS NSTURBED BY NEW WORK, 1 4, UNITS OF STREET CUTS ARE APPROXIMATE. FIMAL LIMITS TO BE 39 .A25. H5B KS (Ty /f 24A6 23 CROSS I� AT AA6SIALKS (Ty?) N3{ 5 NA6 —� Jr 2395 YE 23118 YE - —i� PFFF ryPH , 4 1 YN TWvi%�.. I leW Ersorna i Wv _IS IwI w�6°T36 , DEIEN@ED N THE FIELD BY THE CITY D0491W INSPECTOR, ALL REPAIRS AND TO BE N ACCMOWCE WITH CITY STREET REPAR STANDARDS AT CONTRACTOR EXPENSE. 5. ASPHALT AND CONCRETE REMOVAL LIMITS ARE APPROXIMATE. ADDITICNAL REMOVAL AND REPLACEMENT SHALL BE AT CONTRACTORS EXPENSE AND BE DETERMINED N ME FELO BY ME CSLI INSPECTOR AT ME TIME THE REMOVAL OCCURS. 6. PAVE IT PATCHES SHALL EXTEND A MINNLNr OF TWO FEET ON All - SIDES OF IRILLTY TRENCES. " 7. ME CONTRACTOR SHILL BE RESPONSIBLE FOR REMOVAL OF ALL T �r✓ E u TRASH, SW, GRAVEL, ROAD BASE CONCRETE AND TRENCH Ir w , T NSTAUATKTN MATERIAL rt,. wrt^:y1 8. RETER TO ALL PLAN SHEETS (ARCH. MEP. STRUCTURAL) FOR ADDITIONAL SITE AND BUIDOWS DONamoN. 9. CONTRACTOR TO PROVIDE EROSION CONTROL WATTLES AT PERIMETER O OEMOUTIDN AREA 10. ME CONTRACTOR SHALL MATCH EXIST GRACE AT ALL OMNLYIAYS AMC C U C _ED O 4% U E U Q C O _N � E N _O 10 0- 0 E U U) U a co w IWNTAINN; POSITIVE DRAINAGE AWAY FROM ALL STRUCTURES. COORDINATE WITH OWNER AND ALL ADJACENT PROPERTY OWNERS. City of Fort Collins, Colorado UTILITY PLAN APPROVAL APPROVED. CHECIKED BY wm.a vwa..... MWry au cHECIKJEO BY sm�..•. u•Y °n. CHECIKED BY. i Tr Ell CH110I BY Ps4utl llei�, LIF CHECKED BY. S [n,.amvmvl.mv 0.M 9 Z CHE0QED BY: JAM 5 of 8 As"mYT