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Home My WebLink AboutWPO201900018 Plan - As-built 2020-11-11STIR. D (CLEANOUT) STIR. F (VDOT MH-11) RIM=453.68' 453.85 RIM=453.75' INV. IN 443.57 FROM S INV, IN 444.00 FROM R. B (036') INV, IN 443,57 FROM S INV, IN 445,25 FROM BLDG. (06') INV. OUT 443.57 TO OU 4INV. OUT 443.90 TO STIR, D (06') 460 STIR. B (VDOT H-Q RIM=448,83' 449.1 INV, IN 447.25 FROM STIR. A 06') 455 INV, OUT 44455 TO STIR.E ( 61) 455 444.60 XISTI14G GRAD 450 450 P GRADED 445 445 STIR. -STR, E 115.00 OF 036' HDPE PPE @ 0.50% 440 INV.44000 1 440 STIR. E-STR, DJ 438.17 1.33 OF 06' HDPE PIPE @ 24,81% ( ELEV.=4') 435 STR, D-OUT 435 43,0'OF06'HDE PIPE @ 8.21% PROPOSED UNDERGROUND DETENTION SYSTEM & BYPASS SYSTEM TO OUTFALL INTO EXISTIN RIPRAP LINEE CHANNEL, CONTRACTOR SHALL. REINFORCE EXISTING RIPRAP CHANNEL WIT VDOT STD. Al, EC-1 STONE AT THE LOCATION 430 OF PROPOSED ❑UT ALL, 430 J J DO CD W W (U ou 0J � Ill 0 W L� TR. E (06') TR. C (06') T (036') WEIR PLATE TO BE CENTERED IN THE MANHOLE, AS SHOWN IN PLAN VIEW, AND ANGLED SO THAT IT IS DOWNSTREAM FROM THE PROPOSED ROOF DRAIN & UGD SYSTEM PIPE B-E UNDERGROUND DETENTION SYSTEM PROPOSED SWM DETAIL SCALE:ln=20' +' -- PROPOSED 10' WIDE GRASS STORMWATER MANAGEMENT ACCESS ROAD AND - -- EASEMENT. ACCfSSROAD-SHALL-RAVE-A- SLOPE BETWEEN 2%_M __06!-EMERGENCY 036" INV. \ CLEAN OUT 444.58' i _ -- HDPE BYPASS, TYP 1 44�0' PROPOSED ELEVATED 06"PIPE -ALLOWS MORE SIGNIFICANT & LESS FREQUENT - STORM EVENTS TO SAFELY BYPASS THE UNDERGROUND DETENTION SYSTE VAR LE SDMH ' SWM EASEMENT INSTR If 201900006874 PROPOSED VAR..J WIDTH SWM ESMT. 115.00 LF OF 036" HDPE UNDERGROUND DETENTION PIPE RESTRICTIVE STEEL WEIR PLATE, AT LOW POINT, TO DRAIN SYSTEM. SEE CROPOEDROOFDRAIN, DETAIL ON THIS SHEET. FF M OPOSED UNDERGROUND DETENTION SYSTEM TOENUATE RUNOFF CAUSED OM THIS DEVELOPMENT. UNDERGROUND DETENTION SYSTEM GENERAL NOTES: 1. TRASHRACKS SHALL BE INSTALLED ON ALL OF THE UNDERGROUND DETENTION (UGD) SYSTEM's WEIR PLATE ORIFICES. 2. THE UGD SYSTEM's WEIR PLATE SHALL BE PRE -MANUFACTURED AND DELIVERED TO THE SITE. WEIR PLATE SHALL BE BOLTED TO THE UNDERGROUND DETENTION SYSTEM, OR SIMILARLY FASTENED TO ENSURE IT HAS A SECURE & WATERTIGHT CONNECTION. & ANY RETAINING WALLS AND FOUNDATIONS CONSTRUCTED IN THE VICINITY OF THE UNDERGROUND DETENTION SYSTEM SHALL BE REVIEWED AND APPROVED BY THE STRUCTURAL ENGINEER AND A GEOTECHNICAL ENGINEER. 4. THE EXISTING PARKING LOT AND THE PROPOSED GRADED ACCESS SHALL SERVE AS ACCESS TO THE UNDERGROUND DETENTION SYSTEM. S. CONTACT COLLINS ENGINEERING (434.293.3719) REGARDING ANY QUESTIONS CONCERNING THE UNDERGROUND DETENTION SYSTEM. S. ALL FILL EMBANKMENT MATERIAL SHALL CONSIST PREDOMINANTLY OF SOIL AND BE PLACED IN SUCCESSIVE UNIFORM LAYERS NOT MORE THAN 8 INCHES IN THICKNESS BEFORE COMPACTION OVER THE ENTIRE AREA IN ACCORDANCE WITH THE CURRENT VDOT ROAD AND BRIDGE SPECIFICATIONS. 7. VDOT STD. IS-1 & ST-1 ARE REQUIRED ON THE UNDERGROUND DETENTION SYSTEM's VDOT MH-1 STRUCTURES. 6. ALL FILL SHALL BE PLACED AT 95% COMPACTION AND TESTED BY A GEOTECHNICAL ENGINEER TO ENSURE COMPACTION IS REACHED AND MAINTAINED. 9. PRIOR TO CONSTRUCTION THE CONTRACTOR SHALL TEST -DIG AT THE EXISTING INLET & OUTFALLS TO CONFIRM THE INVERTS AND TO ENSURE THE PROPOSED GRADES CAN BE ACHIEVED. CONTRACTOR SHALL CONTACT COLLINS ENGINEERING OF ANY DISCREPANCIES IN THE HORIZONTAL OR VERTICAL ALIGNMENT PRIOR TO ORDERING AND CONSTRUCTION. 10. ALL EXCAVATION FOR UNDERGROUND PIPE INSTALLATION MUST COMPLY WITH OSHA STANDARDS FOR CONSTRUCTION INDUSTRY (29 CFR PART 1926). 11. CONTRACTOR SHALL PROVIDE AD EQUATE STONE tiACKFILL FOR THE UNDERGROUND DETENTION SYSTEM PIPES IN ACCORDANCE WITH VDOT AND THE MANUFACTURER's REQUIREMENTS. PROPOSED WEIR PLATE �:t♦]l♦A9�a1F3ii GENERAL NOTES: 1. SWM system was backfileld with #57 stone as documented in the asbuilt photos taken between March 25, 2020 and April 9, 2020 and provided to the County. The road above the SWM was proof rolled and the third party inspection was provided. 2. The Peabody school is in acceptance of the condition of the access to the SWM facility and the cost associated with the future access to the facility if work and repairs are necessary on the facility. Regarding note 8:'Site contractor did not perform compaction test on stone backfill used to install SWM facility. Albemarle accepts this circumstance (non-compactable backfill) and photos provided by Applicant as meeting plan approved Note 8 requirement for 95% compaction.' 0 DENOTES AS -BUILT CONDITIONS PROFILE SCALES -PROPOSED UNDERGROUND DETENTION & BYPASS SYSTEM TO OUTFALL INTO EXISTING RIPRAP LINED CHANNEL. CONTRACTOR SHALL REINFORCE EXISTING RIPRAP CHANNEL WITH VDOT STD. Al, EC-1 STONE AT LOCATION OF PROPOSED OUTFALL. PROPOSED L/ERI // N OUT UNDERGROUND DETENTION SYSTEM PR17ARY OUTFAXL _�PROPO§ED MOUNT�BLE CURB FOR TJIE SWM ACCESS ROAD � 85ke?Ga� PROPOSED VDOT FOR INSPECTION & MAINTENANCE, TYP. ACCESS MANHOLES TO BE LOCATED UPSTREAM & DOWNSTREAM OF THE PROPOSED UNDERGROUND �i DETENTION SYSTEM, AS SHOWN. �gy PROPOSED WEIR PLATE ORIENTATION: SCALE 1"=10' 036" WEIR PLATE DETAIL SCALE:i"=5' 3X - 4' ORIFlCES WITH OVERFLOW WEIR IS TRASH RACK INSTALLED HYDRAULICALLY EQUIVALENT u _ y- TO AN ORIFICE WITH AN APPROX. DIAMETER OF = 025.92" TOP OF PIPE's INNER DIAMETER ELEV.= .00' NMI INSTALL(3) THREE 04"MID-FLOW EMERGENCY OVERFLOW SPILLWAY ELEV.= 6.x' ,1 MID -FLOW ORIFICE INVERT= .6 ' ORIFICES WITH TRASHRACKS AT 0.5, 4n o ELEVATION 445.6T TYP. 'o N M ELEV.=4,44,00' INSTALL ONE (1) 03-LOW-FLOW J \-REINFORCED lz GA. ORIFICE WITH TRASHRACK AT LOW STEEL PLATE POINT OF DETENTION SYSTEM AT 3 ORIFICE WITH TRASH RACK INSTALLED. ELEVATION 444-00' V.= 8 General Construction notes for Stormwater anaeeme.. ens 1. All dams and constructed fill to be within 95% of maximum dry density and 2% of optimum moisture content. All fill material to be r app oved by a geotechnical engineer. A geotechnical engineer is to be present during construction of dams. 2. Pipe and riser joints are to be watertight within stormwater management facilities. 3. For temporary sediment traps or basins which are to be converted to permanent stormwater management facilities; conversion is not to take place until the site is stabilized, and permission has been obtained from the County erosion control inspector. 1 "=5' (V) 1"=50'(H) WATERSHED SUMMARY CN Area, ac. 1-year Flow, 2-year Flow, 10-year Flow, cfs cfs cfs DA A (Present) 80 0.22 0.42 0.60 1.15 FDA A(Developed) 1 93 0.22 0.28 0.52 1.10 0 tp -- i -.�,A WniN a %'Mi.' r•.s>frrs� I s R,el • I-(UT� L`15d811� C00 C0000 :Awq,':- ;s -.'Lit^' .::t"I;•y". a ssidy-K wA �R, t 0 0 c It",n'.IctC D 3 F111 C. ` '':ottlmwl I . f I . 1 I . , i�. iib k�9� r L�nl 7' Existing Impervious Area Summary (DA A- Water Quantity) Existing Building 4,350 sf Existing Concrete 475 sf 4,825 sf Proposed Impervious Area Summary (DA A- Water Quantity) Proposed Building 7,050 sf Proposed Sidewalk 1,175 sf 8,225 sf Total Impervious Area Breakdown for Water Quality (Boundary defined by this Plans's Limits of Disturbance) Pre-ReDevelopment ft' Acres Existing Parking Lot 6,050 0.14 Previously Approved Hardcourt 4,950 0.11 Existing Building Proposed to Be Removed 4350 0.10 Existing Walkway 1500 0.03 Existing Parking Lot 6,050 0.14 Proposed Hardcourt 4060 0.09 APPROVED Proposed Building 7,050 0.16 by the Albemarle County Existing Walkways 1,375 0.03 Community Development Department Proposed Amphitheater & Walkways 2,400 0,06 Date 11/24/2020 File WP0201900018 0,48 UNDERDRAIN DRAINAGE DESCRIPTIONS STIR. NO. PIPE INFORMATION INLET INFORMATION COMMENTS DIA. (in.) LENGTH' (ft.) SLOPE (%) INVERT IN INVERT OUT MATERIAL INLET TYPE RIM' ELEVATION A Cleanout 449.60 A-B 6 7.67 6.52% 447.75 447.25 HDPE B MHA 448.83 VDOT STD. IS-1 REQ'D B-C 6 1,33 24.81% 446.25 445.92 HDPE C Cleanout 447.90 C-D 6 115.00 12.04% 445.92 443.57 1 HDPE D Cleanout 453.68 O-0UT 6 43.50 8,21% 443.57 440.00 HDPE B MH-1 448.83 VDOT STD. IS-1 REQ'D B-E 36 115.00 0.50% 444.58 444.00 HDPE E MH-1 453.75 VDOTSTD. IS-1 REQ'D E-D 16 1.33 24.81% 44190 44157 HDPE SWM AS -BUILT SURVEY PERFORMED ON MAY 20, 2020 REV:NOV. 11, 2020 BY: MERIDIAN PLANNING GROUP, LLC 440 Premier Circle, Suite 200 Charlottesville, VA 22901 (P) 434.882.0121 O, LP A c� TI. THY RAY MILLER n L c. No 2065 11/11/20 ®a1 D S I `IO�Lei"s ,� , J R� w O a z ^^Q Ila_ 0 0 V / 0 W Q UJ 0-