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Home My WebLink AboutWPO201800052 Plan - VSMP WPO VSMP 2018-07-13VSMP PLAN%9. SHEET INDEX SHEET 2 EROSION & SEDIMENT CONTROL PLAN SHEET 3 STORM WATER MANAGEMENT PLAN REVISIONS APPROVALS I ENGINEERING E&SC DETAILS LEGEND W WATER LINE (EX. / PROP.) BOUNDARY/ RIGHT-OF-WAY LINE WV® WMO WATER VALVE 1 METER I.F. IRON PIN FOUND SOURCE: Adapted from Installation of Straw and Fabric Filter Barriers for Sediment Control,VA. DSWC PLATE. 3.05-2 SOURCE: VA. DSWC PLATE 3.07-6 FHA -6 FIRE HYDRANT I. S. IRON PIN SET DRAINAGE SWALE DIRECTS FLOW Sherwood and Wyant TO SEDIMENT BASIN YH YARD HYDRANT SETBACK LINE 70' MIN. 1. SET THE STAKES. 2. EXCAVATE A 4"X 4" TRENCH BOAC BLOW -OFF ASSEMBLY EASEMENT LIMITS UIPSLOPE ALONG THE LINE OF SS SANITARY SEWER LINE (EX. / PROP.) CENTERLINE 3" SM -2A ASPHALT TOP COURSE STAKES. COO CLEANOUT CONTOUR LINE (EX. / PROP.) A EXISTING 6'MAX. 2°l0 2% PAVEMENT f - �_-�..,�`' MH-- MANHOLE f-3. — E-2,5075-- DEGREE / DIRECTION OF SLOPE `'`�.�� ,.�� •.,, --. SD STORM LINE (EX. / PROP.) 479.70+ SPOT ELEVATION DIVERSION DITCH A -J _- ,% _ Il .�'- ,--`'+ DIC STORM INLET HP HIGH POINT AGGREGATE BASE �"�-----�. ,,f, " III/ YD® YARD DRAIN LP LOW POINT / •�' f.—�,',/ �^ / DSo DOWNSPOUT DITCH / SWALE SIDE ELEVATION' _ G� ..-� �. GAS LINE (EX. / PROP.) WATER COURSE FLOW ,. - - GVO GMO GAS VALVE / METER BM+ BENCHMARK OHE OVERHEAD ELECTRIC (EX. / PROP.) CG -2 VDOT STD. HEADER CURB EXISTING GROUND 4° UGE UNDERGROUND ELECTRIC (EX. / PROP.) CG -6 VDOT STD. CURB & GUTTER iA PPO POWER POLE CG -12 VDOT STD. HANDICAP RAMP r LP* LIGHT POLE HC HANDICAP PARKING SYMBOL DIP DUCTILE IRON PIPE GUY.' GUY WIRE RCP REINFORCED CONCRETE PIPE 70' MIN. 3. STAPLE FILTER MATERIAL 4. BACKFILL AND COMPACT EM o ELECTRIC METER CMP CORRUGATED METAL PIPE TO STAKES AND EXTEND THE EXCAVATED SOIL. � TRANSFORMER PVC POLYVINYLCHLORIDE PIPE ASPHALT PAVED WASHRACK 10' MIN. IT INTO THE TRENCH. OHT OVERHEAD COMMUNICATIONS (EX. / PROP.) HDPE HIGH-DENSITY POLYETHYLINE PIPE ' PEDO UTILITY PEDESTAL F 2°l0 �,��z �r� i ,Y,�4, l � , ;, ;�, UGT UNDERGROUND COMMUNICATIONS (EX.1 PROP.) VC VITRIFIED CLAY PIPE rFIFE FINISHED FLOOR ELEVATION � � K s � SWMIDWM 12' MIN. EXISTING o/6-6 j j " t 'r - ` .� x / ti - r SINGLE I DOUBLE WATER METER TBR TO BE REMOVED ter' GV D4 GATE VALVE 2 2°l0 TBT TO BE TRANSPLANTED _ PAVEMENT a /�- GRAVEL FILTER °l0 �'w'� `' ,,nll,li y - -K' ; RUNOFF WATER WIRE MESH TBS TO BE SAVED #��._ � 11111 DIVERSION DITCH MIN. POSITIVE DRAINAGE _F �1t' MIN WIDTH AT DESIGN WATER TO SEDIMENT ELEVATION IS 4.0' I TRAPPING DEVICE PLAN VIEW MUST EXTEND FULL WIDTH OF INGRESS AND EGRESS OPERATION MIN. NOTE: A MINIMUM WATER TRAP OF 1" IS REQUIRED WITH A MINIMUM WASH HOSE DIA. OF 1.5" SECTION A—A SET 1Y2" WATER HYDRANT WITH FROST PROOF HYDRANT 3' ABOVE GRADE AND 4' OFF EDGE OF PAVEMENT ALBEMARLE COUNTY CONSTRUCTION ENTRANCE SECTION E-001 N.T.S. FLO/ C_ W J SHEET FLOW INSTALLATION (PERSPECTIVE VIEW) POINTS A SHOULD BE HIGHER THAN POINT B. DRAINAGEWAY INSTALLATION (FRONT ELEVATION) CONSTl[2UCTION OF A SILK' FENCE (VVITHOUT WIRE SUPPORT) E-028 N.T.S. �4} 40 �. .. N _ DEPTH) • . i -- '� mll IIIII till • .•_....,_._.�,•_,.,.�.:._-; �„_—,�.�-..._ !��«"ii�ils'�r/rr f11< •�s.ar+�+��`fii►",�, —'llllll�llllll IIIIIWITH SEDIMENTLi 9F •�•.�� ry •_�:.-.�.►�1,.;.,..�;a.►y .�.�1._.. IT SEDIMENT A' CONCRETE GUTTER 12' CURB INLET _I WIRE MESH SPECIFIC APPLICATION G SEDIMENTFILTERED SPECIFIC APPLICATION THIS METHOD OF INLET PROTECTION IS APPLICABLE AT CURB INLETS WHERE PONDING IN FRONT OF THE STRUCTURE IS NOT LIKELY TO CAUSE INCONVENIENCE OR DAMAGE TO ADJACENT STRUCTURES AND UNPROTECTED AREAS. . GRAVEL SHALL BE VDOT #3, #357 OR 5 COARSE AGGREGATE. GRAVEL CURB INLET SEDIMENT FILTER SECTION E-012 N.T.S. THIS METHOD OF INLET PROTECTION IS APPLICABLE WHERE HEAVY CONCENTRATED FLOWS ARE EXPECTED BUT NOT WHERE PONDING AROUND THE STRUCTURE MIGHT CAUSE EXCESSIVE INCONVENIENCE OR DAMAGE TO ADJACENT STRUCTURES AND UNPROTECTED AREAS. GRAVEL SHALL BE VDOT #3, #357 OR 95 COARSE AGGREGATE. GRAVEL & WIRE MESH DROP INLET SEDIMENT FILTER SECTION E-013 N.T.S. ►Ian Franklin PE, LL( Civil and Site Plan Engineering 427 Cranberry Lane Crozet, VA 22932 434-531-5544 alan@alanfranklinpe.com 4��R'V I H 0p, Ian ranklin Lic. No. 35326 G SsJoNAL ISSUED: SCALE: REVISIONS: um • APPROVED by the Albemarle County Cornmunity,Develnpment Department Date File SHEET OF 3 EROSION &, SEDIMENT CONTROL PLAN NOTES: 1. THE PLAN APPROVING AUTHORITY MUST BE NOTIFIED ONE WEEK PRIOR TO THE PRE -CONSTRUCTION CONFERENCE, ONE WEEK PRIOR TO THE COMMENCEMENT OF LAND DISTURBING ACTIVITY, AND ONE WEEK PRIOR TO THE FINAL INSPECTION. 2. ALL EROSION AND SEDIMENT CONTROL MEASURES WILL BE CONSTRUCTED AND MAINTAINED ACCORDING TO MINIMUM STANDARDS AND SPECIFICATIONS OF THE VIRGINIA EROSION AND SEDIMENT CONTROL HANDBOOK AND VIRGINIA REGULATIONS VR 625-02-00 EROSION AND SEDIMENT CONTROL REGULATIONS. 3. ALL EROSION AND SEDIMENT CONTROL MEASURES ARE TO BE PLACED PRIOR TO OR AS THE FIRST STEP IN CLEARING. 4. A COPY OF THE APPROVED EROSION AND SEDIMENT CONTROL PLAN SHALL BE MAINTAINED ON THE SITE AT ALL TIMES. 5. PRIOR TO COMMENCING LAND DISTURBING ACTIVITIES IN AREAS OTHER THAN INDICATED ON THESE PLANS (INCLUDING, BUT NOT LIMITED TO, OFF-SITE BORROW OR WASTE AREAS), THE CONTRACTOR SHALL SUBMIT A SUPPLEMENTARY EROSION CONTROL PLAN TO THE OWNER FOR REVIEW AND APPROVAL BY THE PLAN APPROVING AUTHORITY. 6. THE CONTRACTOR IS RESPONSIBLE FOR INSTALLATION OF ANY ADDITIONAL EROSION CONTROL MEASURES NECESSARY TO PREVENT EROSION AND SEDIMENTATION AS DETERMINED BY THE PLAN APPROVING AUTHORITY. 7. ALL DISTURBED AREAS ARE TO DRAIN TO APPROVED SEDIMENT CONTROL MEASURES AT ALL TIMES DURING LAND DISTURBING ACTIVITIES AND DURING SITE DEVELOPMENT UNTIL FINAL STABILIZATION IS ACHIEVED. 8. DURING DEWATERING OPERATIONS, WATER WILL BE PUMPED INTO AN APPROVED FILTERING DEVICE. 9. THE CONTRACTOR SHALL INSPECT ALL EROSION CONTROL MEASURES PERIODICALLY AND AFTER EACH RUNOFF -PRODUCING RAINFALL EVENT. ANY NECESSARY REPAIRS OR CLEANUP TO MAINTAIN THE EFFECTIVENESS OF THE EROSION CONTROL DEVICES SHALL BE MADE IMMEDIATELY. 10. ALL FILL MATERIAL TO BE TAKEN FROM AN APPROVED, DESIGNATED BORROW AREA. 11. ALL WASTE MATERIALS SHALL BE TAKEN TO AN APPROVED WASTE AREA. EARTH FILL SHALL BE INERT MATERIALS ONLY, FREE OF ROOTS, STUMPS, WOOD, RUBBISH, AND OTHER DEBRIS. 12. BORROW OR WASTE AREAS ARE TO BE RECLAIMED WITHIN 7 DAYS OF COMPLETION PER ZONING ORDINANCE SECTION 5.1.28. 13. ALL INERT MATERIALS SHALL BE TRANSPORTED IN COMPLIANCE WITH SECTION 13-301 OF THE CODE OF ALBEMARLE. 14. BORROW, FILL OR WASTE ACTIVITY INVOLVING INDUSTRIAL -TYPE POWER EQUIPMENT SHALL BE LIMITED TO THE HOURS OF 7:00 AM TO 9:00 PM. 15. BORROW, FILL OR WASTE ACTIVITY SHALL BE CONDUCTED IN A SAFE MANNER THAN MAINTAINS LATERAL SUPPORT, OR ORDER TO MINIMIZE ANY HAZARD TO PERSONS, PHYSICAL DAMAGE TO ADJACENT LAND AND IMPROVEMENTS, AND DAMAGE TO ANY PUBLIC STREET BECAUSE 0 SLIDES, SINKING, OR COLLAPSE. 16. THE DEVELOPER SHALL RESERVE THE RIGHT TO INSTALL, MAINTAIN, REMOVE OR CONVERT TO PERMANENT STORMWATER MANAGEMENT FACILITIES WHERE APPLICABLE ALL EROSION CONTROL MEASURES REQUIRED BY THIS PLAN REGARDLESS OF THE SALE OF ANY LOT, UNIT, BUILDING OR OTHER PORTION OF THE PROPERTY. 17. TEMPORARY STABILIZATION SHALL BE TEMPORARY SEEDING AND MULCHING. SEEDING IS TO BE AT 75 LBS/ACRE, AND IN THE MONTHS OF SEPTEMBER TO FEBRUARY TO CONSIST A 50150 MIX OF ANNUAL RYE GRASS AND CEREAL WINTER RYE, OR IN MARCH AND APRIL TO CONSIST OF ANNUAL RYE, OR MAY THROUGH AUGUST TO CONSIST OF GERMAN MILLET. STRAW MULCH IS TO BE APPLIED AT 80LBS/100SF. ALTERNATIVES ARE SUBJECT TO APPROVED BY THE COUNTY EROSION CONTROL INSPECTOR. 18. PERMANENT STABILIZATION SHALL BE LIME AND FERTILIZER, PERMANENT SEEDING, AND MULCH. AGRICULTURAL GRADE LIMESTONE SHALL BE APPLIED AT 90LBS/1000SF, INCORPORATED INTO THE TOP 4-6 INCHES OF SOIL. FERTILIZER SHALL BE APPLIED AT 1000LBSIACRE AND CONSIST OF A 10-20-10 NUTRIENT MIX. PERMANENT SEEDING SHALL BE APPLIED AT 180LBS/ACRE AND CONSIST OF 95% KENTUCKY 31 OR TALL FESCUE AND 0-5% PERENNIAL RYE GRASS OR KENTUCKY BLUEGRASS. STRAW MULCH 1S TO BE APPLIED AT 80LBS/100SF. ALTERNATIVES ARE SUBJECT TO APPROVED BY THE COUNTY EROSION CONTROL INSPECTOR. 19. MAINTENANCE: ALL MEASURES ARE TO BE INSPECTED WEEKLY AND AFTER EACH RAINFALL. ANY DAMAGE OR CLOGGING TO STRUCTURAL MEASURES IS TO BE REPAIR IMMEDIATELY. SILT TRAPS ARE TO BE CLEANED WHEN 50% OF THE WET STORAGE VOLUME IS FILLED WITH SEDIMENT. ALL SEEDED AREAS ARE TO BE RESEEDED WHEN NECESSARY TO ACHIEVE A GOOD STAND OF GRASS. SILT FENCE AND DIVERSION DIKES WHICH ARE COLLECTING SEDIMENT TO HALF THEIR HEIGHT MUST BE CLEANED AND REPAIRED IMMEDIATELY. 20. ALL TEMPORARY EROSION AND SEDIMENT CONTROL MEASURES ARE TO BE REMOVED WITHIN 30 DAYS OF FINAL SITE STABILIZATION, WHEN MEASURES ARE NO LONGER NEEDED, SUBJECT TO APPROVAL BY THE COUNTY EROSION CONTROL INSPECTOR. POLLUTION PREVENTION PLAN NOTES POTENTIAL POLLUTANT SOURCES • THE POTENTIAL POLLUTANT SOURCES ASSOCIATED WITH THE LAND DISTURBANCE OF THE SITE, AS ILLUSTRATED BY THE DISTURBANCE AREA, CONSISTS OF MINOR MAINTENANCE AND EQUIPMENT FUELING OPERATIONS. THESE ACTIVITIES SHALL BE LIMITED TO THE SPECIFIC AREA SHOWN ON THIS PLAN. IN ADDITION, THERE WILL BE FERTILIZER, SEED, AND STRAW TEMPORARILY STORED AND UTILIZED FOR BOTH TEMPORARY AND PERMANENT SEEDING OPERATIONS. • THERE WILL BE A PORTA-JOHN, A DUMPSTER FOR SOLID WASTES, A FREIGHT CONTAINER FOR STORAGE MATERIALS, AND AN ABOVE GROUND CONCRETE WASH-OUT AREA LOCATED IN THE PROPOSED CONSTRUCTION STAGING AREA AS SHOWN ON THE PLAN. ALL MATERIAL DELIVERY AND STORAGE SHALL OCCUR IN THE CONSTRUCTION STAGING AREA. ALL VEHICLE, MATERIAL, AND EQUIPMENT WASHING SHALL OCCUR IN THE STAGING AREA ORAT THE WASH RACK. THE CONTRACTOR SHALL ENSURE THAT THE DRAINAGE AREA FROM THESEE ACTIVITIES FLOWS TO SEDIMENT TRAPPING DEVICES. RECEIVING WATERS • RUNOFF FROM THIS SITE DRAINS TO MANMADE STORM DRAIN SYSTEMS THAT FORM TRIBUTARIES OF MEADOW DISTURBED AREA IS .7 ACRES. PROPOSED SEDIMENT CREEK SEVERAL PARCELS DOWNSTREAM. THE PROPOSED STURB 9 8 AC S OS BASINS, INLET PROTECTION ON EXISTING AND PROPOSED SITE DROP INLETS, AND SILT FENCE WILL ADEQUATELY PROTECT AGAINST SILTATION DOWNSTREAM. STORMWATER MANAGEMENT • THIS SITE HAS BEEN DESIGNED IN ACCORDANCE WITH 4VAC25-870-93 PART 11-C. SEE THE WPONSMP PLAN FOR SPECIFICS RELATING TO STORM WATER QUALITY AND QUANTITY COMPLIANCE. INSTALLATION & MAINTENANCE • ALL EROSION CONTROL MEASURES ARE TO BE CONSTRUCTED IN ACCORDANCE WITH THE VIRGINIA EROSION AND SEDIMENT CONTROL HANDBOOK, THIRD EDITION 1992. • ALL LAND DISTURBING ACTIVITIES SHALL BE IN ACCORDANCE WITH VIRGINIA EROSION AND SEDIMENT CONTROL LAW AND REGULATIONS 4VAC25-840. • EXISTING VEGETATION SHALL BE PRESERVED TO MAXIMUM EXTENT PRACTICAL AND DISTURBED PORTIONS OF THE SITE SHALL BE STABILIZED AS QUICKLY AS POSSIBLE. • IF PERIODIC INSPECTIONS OR OTHER INFORMATION INDICATED THE NEED FOR MODIFYING OR PROVIDING ADDITIONAL EROSION CONTROL MEASURES, THE OPERATOR MUST REPLACE OR MODIFY THE MEASURES AS SOON AS POSSIBLE, AS WELL AS UPDATE THE SWPPP. • ALL CONSTRUCTION MATERIALS AND DEBRIS SHALL BE STORED WITHIN THE LIMITS OF DISTURBANCE. • ANY LITTER EXPOSED TO STORMWATER SHALL BE PREVENTED FROM BECOMING A POLLUTANT SOURCE IN STORMWATER DISCHARGES. THE CONSTRUCTION SITE SHALL BE MONITORED DAILY TO CONTROL LITTER. • TEMPORARY PORTA-JOHNS SHALL BE UTILIZED DURING CONSTRUCTION AND SHALL IBE LOCATED WITHIN THE DISTURBED AREA. • ALL POLLUTION CONTROL MEASURES SHALL BE PROPERLY MAINTAINED IN AN EFFECTIVE OPERATING CONDITION IN ACCORDANCE WITH GOOD ENGINEERING PRACTICE AND, WHERE APPLICABLE, MANUFACTURER RECOMMENDATIONS. IF SITE INSPECTIONS IDENTIFY CONTROL MEASURES ARE NOT OPERATING EFFECTIVELY, MAINTENANCE SHALL BE PERFORMED AS SOON AS POSSIBLE TO MAINTAIN CONTINUED EFFECTIVENESS OF THE STORMWATER CONTROLS. • IN THE EVENT THAT ADDITIONAL AREAS ARE BEING UTILIZED FOR CONTAMINATE DISPOSAL, NOT SPECIFICALLY CONTROLLED BY AN APPROVED EROSION CONTROL MEASURE, THE PLAN SHALL BE IMMEDIATELY REVISED TO REFLECT ALL CURRENT, POTENTIAL POLLUTANT LOCATIONS, AS WELL AS SPECIFY ANY ADDITIONAL MEASURES NECESSARY FOR ASSURANCE OF THE PROPER MAINTENANCE AND APPLICABLE SPILL PREVENTION CONTROL. SPILL PREVENTION INFORMATION • ALL FUELING AREAS MUST PROVIDE A MEANSU OF SECONDARY CONTAINMENT IN CASE OF FUEL LEAKS OR SPILLS. THIS COULD INCLUDE THE USE OF SPILL BUCKETS AND/OR FUEL SPILL MATTING, OR ANY TYPE OF DEVICE THAT TRAPS AND CONTAINS THE FUEL AND WHICH CAN BE REMOVED FROM THE SITE AND TAKEN TO AN APPROVED DISPOSAL LOCATION. • THE CONCRETE WASHOUT AREA MUST BE LOCATED UPSTREAM OF A SEDIMENT TRAP OR BASIN. • A SILT FENCE OR BERM MUST BE INSTALLED AROUND EACH PORTA-POTTY AND SOLID WASTE DUMPSTER AREA TO PREVENT AND'OR LIMIT ENVIRONMENTAL IMPACTS. CONSTRUCTION SEQUENCE: 1. UTILIZE EXISTING PAVED ENTRANCE FOR CONSTRUCTION ENTRANCE. 2. INSTALL SILT FENCE AT LOWER PERIMETER OF BANK SITE. 3. UTILIZE EXISTING PAVED AREAS FOR PARKING, LAYDOWN, EQUIPMENT STORAGE, CONTRACTOR TRAILER, AND OTHER POLLUTION PROTECTION MEASURES. 4. INSTALL AND MAINTAIN INLET PROTECTION ON EXISTING STORM STRUCTURES. 5. PROTECT EXISTING BIO -FILTER FROM SEDIMENT LADEN RUN-OFF FROM BANK SITE BY ANY MEANS NECESSARY. 6. RE-ESTABLISH TURF VEGETATION ON ALL DISTURBED, NON -PAVED AREAS. ESC LEGEND: SOIL DATA CONSTRUCTION ENTRANCE 8C3 - BRADDOCK CLAY LOAM, 7 TO 15 PERCENT SLOPES, CE SEVERELY ERODED 3.02 VA E&SC STD. 81 B - THURMONT LOAM, 2 TO 7 PERCENT SLOPES SILT FENCE 88 - UDORTHENTS,LOAMY SF 3.05 VA E&SC STD. IP INLET PROTECTION 3.07 VA E&SC STD. TO TOP SOILING 3.30 VA E&SC STD. TS TEMPORARY SEEDING 3.31 VA E&SC STD. PS PERMANENT SEEDING 3.32 VA E&SC STD. MU MULCHING 3.35 VA E&SC STD. !C) DUST CONTROL 3.39 VA E&SC STD. PROJECT LIMITS 34,000 SF (0.78 ACRES) r�. ,AYLAND 5=4) _- �TE RIM= ?02:82_ AD - -INV IN= 693.62 INV t`�IJT- _693.52 / 'r _.Y / 1414 I �_..__ vo PLUG SILT NCE 061` ! - _ __ ,,, ... 702 SF - - �% / +, - _ - - 70 - w..- -- NEW PRIVATE -- _ 1 I IV{I -,_ JL IP CURB INLET - PROTECTION, CONSTRUCTION STAGING AREA 20' ACSA EASEMENT SILT FENCE, TYP SF-- - 0 10` 20' 40' 80' fool Alan Franklin PE, LLC Civil and Site Plan Engineering 427 Cranberry Lane Crozet, VA 22932 434-531-5544 alan@alanfranklinpe.com �;'p\;T H 0r i .C) Alan G. Franklin Lic. No. 35326 w 1'O ^R!+ .ONAL Q Q Z w � wU�Z EL Q � � > O U) w 0Wm01 a 2 U m ISSUED: SCALE: REVISION SHEET 06-21-18 1R=20 0 15, 30, 60, V v, !j!� i ;< TMP 56A2-1-37 Now or Formerly ANITA D. WASHINGTON D.B. 604 PG. 094 Zoned: C-1 Comp. Plan: CT 4 Urban Center Use: Urban RATIONAL METHOD WORKSHEET Pyojecli Biichwood Place Date-, 11/2/2006 FROM APPROVED PLANS Designer: AGF Watershed ID: Post -Development to Bio -Retention Drainage Area: 3.64 Acres c -factor: 0,79. (see worksheet) tc: 5.95 mins. (see worksheet) Q(2): 14.19 cfs (prior to detention) Q(10): '18.30 cfs (prior to detention) Time of Concentration Worksheet Weighted c -factor Worksheet Overland Flow Time cove'l Source: Seelye Chart as modified in VDCT Drainage Manual (Fig. L Impervious (m 1.6.1.1 on Page 1-13E) PeNous LanM Notes: 5.9 1) Length of overland flow always - 200 ft 50 2) Calculate a separate Ta for each ground cover condition along the flow path Enter Length of Strip (ft) sample "C" values: ALLOWABLE IMPERVIOUS 383 Enter Slope (% or ft/ 1 00ft) 0.22 Dense 9(assAREA FROM APPROVED PLANS 0x90 Enter Rational Method "C" wlue t1, 28 Average grass 0, 36 Poor grass Result Tc (minutes) 0.48 Bare soil 0,90 Pavement 2 TMP 56A2 -3_B-1 T 56A2 -3-B-8 CL Now or Formerly Now or Formerly Q) FLORENCE D. MASSIE TMP 56A2 -3-B-7 JONATHAN ORD.B. 335 PG214 Now or Formerly CAROL TMP 56A2 -3-B-9 Zoned. R-2 TIVIP 56A2 -1-38A I WAVERLY H. DAVIS QUESENBERRY Now or Formerly Comp. Plan- CT 1 & 2 Now or Formerly A W.B. 116 PG. 178 D.B. 1736 PG. 734 I BETSY CLAYTON Urban Edge FLORENCE D. MASSIE Zoned: R-2 Zoned- R-2 DENOME e Use: Urban D.B. 420 PG. 077 0 15, 30, 60, V v, !j!� i ;< TMP 56A2-1-37 Now or Formerly ANITA D. WASHINGTON D.B. 604 PG. 094 Zoned: C-1 Comp. Plan: CT 4 Urban Center Use: Urban RATIONAL METHOD WORKSHEET Pyojecli Biichwood Place Date-, 11/2/2006 FROM APPROVED PLANS Designer: AGF Watershed ID: Post -Development to Bio -Retention Drainage Area: 3.64 Acres c -factor: 0,79. (see worksheet) tc: 5.95 mins. (see worksheet) Q(2): 14.19 cfs (prior to detention) Q(10): '18.30 cfs (prior to detention) Time of Concentration Worksheet Weighted c -factor Worksheet Overland Flow Time cove'l Source: Seelye Chart as modified in VDCT Drainage Manual (Fig. L Impervious (m 1.6.1.1 on Page 1-13E) PeNous LanM Notes: 5.9 1) Length of overland flow always - 200 ft 50 2) Calculate a separate Ta for each ground cover condition along the flow path Enter Length of Strip (ft) sample "C" values: ALLOWABLE IMPERVIOUS 383 Enter Slope (% or ft/ 1 00ft) 0.22 Dense 9(assAREA FROM APPROVED PLANS 0x90 Enter Rational Method "C" wlue t1, 28 Average grass 0, 36 Poor grass Result Tc (minutes) 0.48 Bare soil 0,90 Pavement Shallow Concentrated Flow Time Source: SCS Velocity Graph as published in Virginia Erosion and Sediment Control Handbook, Third Edition (Plate 5-2 on Page V-12) Notes: 1) Not intended for wel(-defined channels - see channel flow caiculation 2) Calculate a separate Tc for each ground cover condition along the flow path 265.00 Enter Length of Flow (ft) �300 Enter Slope (% orfl/100ft) 1.59 Result Tc (minutes) IF UNPAVED Result To (minutes) IF PAVED Pipe Flow Time Assumes 10 ft1s velocity in pipe 77T-_ Enter Length of Flow in Pipe (ft) Result To (minutes) Rainfall Intensity (Albemarle County, Virginia) 5 5.9 5.7 10 5,9 6,4 25 5.9 7.1 50 5.9 77 100 5.9 8.3 Intensities derived from NOAA Atlas -14 Rainfall Precipitation Frequency Data 114 W"R_` SHEET RA NAME L, THOD 1: Birchwood Phice Date: 11/2/2 006 FROM APPROVED PLANS Designer: AGF Watershed ID: Post -Development bypassing Bio -Retention Drainage Area: 0.30 Acres c -factor: 0,50 (see worksheet) tc: 13.62 mins. (see worksheet) Q 2), 0.54 ofs 0(10): 0.71 cls Time of Concentration Worksheet Overland Flow Time 116 Source: Seelye Chart as modified in VDOT Drainage Manual (Fig. 1-5.1.1 on Page 1-13E) 4.7 Notes' - 13.6 1) Length of overland flowalways - 200 ft 50 2) Calculate a separate Tc for each ground cover condition along the flow path 50.00 Enter Length of Strip (ft) Sample "C" values: 0.33 Enter Slope (% or lt/100ft) 0,22 Dense grass 0,28 Enter Rational Method "C" value 0.28 Average grass 0-36 Poor grass Result Tc (minutes) 0.48 Bete soil 0.90 Pavement Rainfall Intensity (Albermarle County, Virginia) 5 116 4.2 10 13,6 4.7 25 13.6 5.3 50 13.6 5.7 100 13.6 6-2 Intensities derived from NOAH Atlas -14 Rainfall Precipitation Frequency Data Weighted c -factor Worksheet TOTAL POST -DEVELOPMENT RUN-OFj Q2 =2.41 + 0.54 2.95 cfs Q10=3.15+0.71 3.86 cfs DETENTION COMPLIANCE Project Area (acres) = 18 (roughly equal to lits of disturbance} Area Detained (acres) = 3.6 Percent Capture = 96% (should be betvv een 80% arsd 120%) 2 < CL CL Q) :3 0 0 Remarks Detained Areas Post A (Bic*Retention Basi 3,64 1 3,87 1 118.30 1 315 wins to Parrot Creek Un -detained Areas Post 8 (Errbankmant Slope) 0.30 nia, 0,71 n/a Drains to Rarrot Creek x" Vjc7 < 77 X, xx pos- Tv < fJ a" H, SWM PLAN ANALYSIS 120' 150, THE HATCHED AREA REPRESENTS EXISTING AND PROPOSED IMPERVIOUS AREA TREATED BY THE EXISTING BIO -FILTER AFTER PHASE 1 OF BIRCHWOOD PLACE IN COMPLETE. THE EXISTING BIO -FILTER WAS DESIGNED TO TREAT 2.70 ACRES OF IMPERVIOUS AREA WITHIN ITS 3.64 ACRE WATERSHED. AFTER COMPLETION OF THE PHASE 1 (UVA CREDIT UNION) IMPROVEMENTS, THE TOTAL IMPERVIOUS AREA WITHIN THE BIO -FILTER WATERSHED WILL BE 2.00 ACRES. 0.70 ACRES OF IMPERVIOUS AREA WILL BE AVAILABLE TO THE PHASE 2, FUTURE MIXED USE DEVELOPMENT AT THE REAR OF THE SITE, WHICH WOULD BE ADEQUATE BASED ON THE CURRENTLY APPROVED SITE PLAN. Alan Franklin PE, LLC Civil and Site Plan Engineering 427 Cranberry Lane Crozet, VA 22932 434-531-5544 alan@alanfranklinpe.com efol o 1W a 7 Alan G. Franklin Lic. No. 35326 10 4j, <11 LIS /0NAL ISSUED: SCALE: REVISIONS: I SHEET 06-21-18 1 H = 30'1 nommmmmt