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WPO202000003 Calculations 2020-06-29
SHIMP ENGINEERING, P.C. Design Focused Engineering January 15, 2020 Engineering Review Albemarle County Department of Community Development 401 McIntire Road Charlottesville, VA 22902 TH v . SHIMP ic. o. J5183 -P S U ct 0 �NNAL Regarding: WPO 2020xxxxx 2511 Avinity Dr VSMP — SWM Calculation Packet Dear Emily, Enclosed is the stormwater calculation packet for 2511 Avinity Dr. The development property has an area of 0.91acres and a disturbed area of 1.12 acres. The project is a private redevelopment of a site. The proposed stormwater design meets water quality requirements set forth in 9VAC25-870-65 and water quantity requirements set forth in 9VAC25-870-66-B(3) and 9VAC25-870-66-C. SWM Quality SWM Quality is satisfied by providing required nutrient treatment for the development. 9VAC25-870-65 requires that the total phosphorous (TP) nutrient load created by the site development be treated in accordance with the VRRM Redevelopment Spreadsheet reduction requirements. To achieve nutrient treatment, a purchase of nutrient credits for the frill amount of required treatment shall be made. This amount totals 1.14 lbslyr phosphorous credits and satisfies the nutrient treatment requirement. Treatment Required Total Phosphorous) Treatment Provided Total Phosphorous) 1.14 lblyr 1.14 lblyr SWA] Quantity SWM Quantity is satisfied by analyzing concentrated runoff from the development at 2 Points Of Analysis (POA) within a channel downstream of the development property. 9VAC25-870-66-B(3) requires that concentrated runoff from development at each POA meet the energy balance equation. To achieve this, most concentrated runoff from the site will be routed to an underground detention facility which discharges to POA 1. The runoff from the detention, along with unmanaged (bypass) runoff for the site to POA 1, meets the energy balance equation. At POA 2, the postdev runoff from the site has less volume and peak flow than the predev conditions, so the energy balance equation is also met at POA 2. 9VAC25-870-66-C requires that the post-dev 10- year runoff at both POA's not exceed the pre-dev 10-yr runoff. This condition has also been satisfied. See table below for summary. APPROVED by the Albemarle County Community 2eevelopment Department Date 66%% UU 912 E. High St. Charlonesville, VA 22902 1 434.227,5140 1 shimp-engineertng.com POA 1 Pre-dev Peak Runoff Max. Allowed Peak Runoff Post-dev Peak Runoff 1-Yr 0.43 cfs 0.26 cfs 0.24 efs 10-Yr 1.89 cfs 1.89 cfs 1.35 cfs POA 2 Pre-dev Peak Runoff Max. Allowed Peak Runoff Post-dev Peak Runoff 1-Yr 0.97 cfs 0.97 cfs 0.42 cfs 10-Yr 2.57 cfs 2.57 cfs 1.13 cfs Individual Channel Capacity The proposed development outlets to 4 existing inlets on Avon St. For each one of these inlets, the postdev runoff is less than the predev runoff. This is shown on the LD-204 worksheet, and the runoff flows from the design requirement of I=4.0 are shown in the table below. Since the runoff to each inlet is less than the predev condition, no further capacity analysis was performed. Inlet Pre-dev Peak Runoff Post-dev Peak Runoff X1 0.54 cfs 0.22 cfs X2 0.45 cfs 0.37 cfs X3 0.27 cfs 0.20 cfs X4 0.74 cfs 0.34 cfs If you have any questions about this calculation packet please do not hesitate to contact me at: keane@shimp- enaincering.co engineering.com or by phone at 434-299-9843. Regards, Keane Rucker, EIT Shimp Engineering, PC Contents: Water Quality Calculations: Pre-Dev VRRM Land Cover Map Post-Dev VRRM Land Cover Map VRRM Redevelopment Spreadsheet Water Quantity Calculations: Pre-Dev POA Drainage Map Post-Dev POA Drainage Map Energy Balance Equation TOC Calculations Predev HydroCAD Report Postdev HydroCAD Report Inlet Drainage Spreadsheet Pre-Dev Inlet Drainage Map Post-Dev Inlet Drainage Map VDOT LD-204 Inlet Capacity VDOT LD-229 Storm Drain Capacity Independent Reports: Excerpt from NRCS Soils Report NOAA Precipitation Report Water Quality Calculations: Pre-Dev VRRM Land Cover Map Post-Dev VRRM Land Cover Map VRRM Redevelopment Spreadsheet I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ■ I tv i Ii 5 B HSI B , I , I I I I I I I I I I I I I I AVINITY DRIVE • 60' PRIVATE RIGHT-OF-WAY LIMITS OF DISTURBANCE o p. 71B HSG B I r r 01 a 1 1 1 _ r I I I I I 1 I + I ��MiTs oF'o'r UREA L � "+CF �r44 i I 88 HSG D 'Rift • ~ ftift . I I 4` 1 1 1 2511 AVI N ITY PREDEV VRRM MAP DISTURBED AREA: 1.12 AC HSG B AREA: 0.59 AC HSG D AREA: 0.53 AC WOODS: 0.00 AC TURF: 1.02 AC HSG B: 0.52 AC HSG D: 0.50 AC IMPERV: 0.10 AC HSG B: 0.07 AC HSG D: 0.03 AC 30 0 30 60 90 r— r—�,_ r Scale: 1 "=30' �d 60' PRIVATE RIGHT-OF-WAY LIN am VAW + ---- r-__ - 1 I + I I I f II f I f I I I � I ff� r 2511 AVI N ITY POSTDEV VRRM MAP TOTAL SITE: 1.12 AC WOODS: 0.00 AC TURF: 0.42 AC HSG B: 0.30 AC HSG ❑: 0.12 AC IMPERV: 0.70 AC HSG B: 0.29 AC HSG D: 0.41 AC `--------------- 30 0 30 00 90 Scale: 1 "=30' ❑ 2011 RMP SLandwds and SpeclncM lots 0 201q Oran 1 FAP Standards am spedbeatlmrs P.Oje t Na I 2511 Avinity Drlve Dater 1/12/2020 Linear Development Project? No Site Information Post -Development Project (Treatment Volume and Loads) Enter Total Disturbed Area {acres) 4 1.22 Cover AScR. BSoik CSois DSeils Totals Fprpsrlepea Spa.( -,I undgturbed forcu�ppnn sparn G W Man�gd Turt lacTn] -- deturhed. graded for yardsor nrMrwrilp bP mp-*.sna d O.S2 0.50 1.02 Impervious Caner i-I „ „_ „ -1 OA D wsneer - verstvn a.0 wris[airtvalsrez wk.1191 nedk A Sags aSp* CScRs DSoils TMaIP FaeesrMsw..Spxe [xre.l u r,Mpes[ed 000 pmMpted Foryt�nrsnspam nr mR. land tad Managed Turt lacpa] . d+rturbed. graded For 042 yardso+ nlhpr ruff tp be mowed✓maneged 0.39 0.12 Impervious [euerlwti] 0.29 0.41 P-70 Area C14-ki ON. OK. OK. OK. 1-12 r....�.w. .....N r..erC..:e..k fR..i Pre-Reoev WMi M I.Istee adjusted+ Fo 40pen Space Cover (acres) OAO 0-00 w_ eigh.ee Rv[torese[ 01M W. 'd Forest 0% om Mara$ad iiaf Corer )acre[ i.02 OR2 Wejghted Rvttp 0.22 ❑ 21 Y. Managed Turf 111% 91% Impervious [over lanes[ 0.20 0-19 Rutlmperoiousl 0.95 0-95 %hnpemiom 9% 19% Total site Area lanes[ 1.11 D.52 &.Rv 1 0.39 0-36 Treatment Volume and Nutrient Load Pre-ReDerdopmene Treatment VWume [�� O.P770 O.atSM1 Pre-ReDerNopmenr ireannen! VWume [nrbi[feer] t 176 672 Pre-ReOevelopmern TP Lned []6tyrl 0.74 10,42 P. R Dan*prntnt W Lead per a- Ry_."l - O.Br 6ase11ne iR Laid IllaNO IPA11W-ilrt smli W pre redrrelwmeMarea ealudlM psnov+ taro prmaeea roc nev anperrias ewer) 0.21 Adfypred LnrM e- Summary 'rc RsArvrh➢mono hM Fvrer mhw P-ro.fprda-Mrcw%l ensvwrc aY T+m+oped rNyJ aTevpe pa'aPvsed/or new mmmrova cwvr WW.rrd rorM PFrcsge+s mmRtrnr wWh Pasc Rravr.-ppmrnt v.�epge frr.Nu. �FarP9e y arty rmperv�wn rewrl. 'Wumn+nhv Wd rvdevp'pn.rqudemrnrp-new unarm", myer l Srd pn new ie kPmeat hod W. 0.41,wyp /rear) [heck: SMP Design Spedf octIons [1st: 2013 Draft Res & Specs Linear pro)ecc? No lend rover areas entered rorceedy9 yr Total disturbed area entered? ,/ A Soik 0Soils CSoils OSoRs Fora[�Open space O.OI 0+03 0.04 0.05 Managed Tuff D.15 0.7rJ 0.72 0.25 Impwloua Corer 0.95 0.95 0.95 0.95 land [Doer swn»nry-Pnsl fFrnulj Innd Cover Summery -Pest PnsLi C.elapment FnreOpen Space ieM [ever5urxrxmJFAefe Pnfs-0erelepment Ne`rlmpervleus .. ... Post Re19 v &New Impervious Fore>VOpen Space [ . ere-.] 000 C.- [.-I _ rVelgri[ed RWforeu] v-00 -MCorest 0% Managed Tuff Cover .. -kghtld R )arose) D.m 9i Fares[ 0% Managed Tud 1- o.Q 0-41 I_.[ MIE!"d Rr[turn 0121 %Managed Tart 91% ReD�.�.lmprry & New lmpervieus[ r Weightrd Pr JNrry 0.21 %Managed Turf AM Impervious Carer IeereP] o_7u cnverlaael 0-10 avfmpenlowl 0.95 Xlmperraws 19%------- 7ota11te0ev. SRe Area ICI rn Ro(lmpervlous] 1. RHRnpernousV 0-95 %Imyervicua 63% Fh.PSheArea[anesl 1.11 G51 [serer) IleDev Sae&v P-i6 .. .... Fad Peal aer9N Rr ai7 Treatment Volume and NUtnent Load Find Povt- Development 0a579 p aeoercAepnresd Treaty Vaiume M154 Peat Derelapneid Treatmens Volume 0.0475 Trearman Vobame l�-Ir] Iave-R[ [aere�l[j Find Poat- Deuelopmern Ao°r De k nb t Pace-Derelopmens ireevnenS VoMame 2.741 Treannem VWume 671 lcuhlc }ee[I Trcebmeid VWume(cubic iA69 leer[ [pdncfees] Finak Pest- DevefepmentTP 1,12 Pp°s t Load ITPI OAZ Pashnerdnk-TP 1.i0 load llWyrf' Lod[lhl'PI IIh1Yrl wm�.-., t r l e .:m .J TP wad perlanv i-se wad Der arry CAL IlWewelnl IIWer�ery.1 Mew. Redpnlpn Peeeired larloy ore- pa% eoeawlopmoM wall TP Load Redudt . TP Load Reduction Required }pr O Redeveloped Area Required for New 1.05 Impervious Area Ilhlyrl [Ibtya] TP Load Reduction Required IIblyrl 1 1,1A Water Quantity Calculations: Pre-Dev POA Drainage Map Post-Dev POA Drainage Map Energy Balance Equation TOC Calculations Predev HydroCAD Report Postdev HydroCAD Report Inlet Drainage Spreadsheet Pre-Dev Inlet Drainage Map Past-Dev Inlet Drainage Map VDOT LD-204 Inlet Capacity VDOT LD-229 Storm Drain Capacity I I I I I I I I I I I I I 2511 AVI N ITY PREDEV POA A"'NITY ol�ly 4 DRAINAGE MAP 60P IVATE RIGHT-OF-WAY � � � 1 _ 4 532.7 - a-ra-�r.r.rair.r.� ■ Mown � 1 ■ /r 1 f . ■1 AVON PROPERIE5 L C ■ TMP 091A0--00--00--D ❑A 1 — y ��• ■ ZONED PRD ■ OPEN SPACE 1 I 5.B HS B , I S 17° PREDEV DRAINAGE AREA (AREA WITHIN LIMITS OF 529. i ' 71B i ' DISTURBANCE) ` l ' HSG B , ' DRAINAGE TO POA 1: 0.61 AC 88 San a TURF: 0.58 AC ■ HSG D HSG B: 0.49 AC Q TO POA If HSG D: 0.09 AC ' 26760 SF ,� IMPERV: 0.03 AC o , 4 To POA 2 ALL HSG B — + ---2930 SF KAITLIN E CY TGC 1: 11.2 MIN ' I TMP 091A —00— ' ■ 1 — oa' SINGNED AMIDLY DRAINAGE TO POA 2: 0.53 AC ■ ATT HED r TURF: 0.10 AC HSG B: 0.06 AC r ► II HSG D: 0.40 AC IMPERV: 0.10 AC � Mom 4"*+ar j r I HSG B: 0.04 AC C � ■ � i fr r Y + 1 + I HSG D: 0.03 AC � Ir TOC 2: 11.7 M I N DWIN BARBOUR TMP—00-035GO ZONED I I + ■ 4~~~,■`;;;;;� �l r J SINGLE FAMILY REST NMAL I I JERK W SR OR LAURA J MOSS ! f T P 09000-00-035AO ZONED R1 t ❑B 541 PC 642 SI LE FAMILY RESISENTIAL - L4'~ I I 30 0 30 60 90 Scale: 1 "=30' r_-_-_--i r �I rf AVINITY DRIVE^ I _ y 60' P.RIVATE RIGHT-OF-WAY - r J � _ + + r+ + + �+ + + + + ■ _ 4 r + + + X �11 LL I O 2 ti. !Q I mom a+ �_ 17 (`------------- 30 0 Scale. 2511 AVINITY PGSTD EV PGA DRAINAGE MAP DRAINAGE TO PDA 1: 1.00 AC. INCLUDES DRAINAGE TO BMP AND BYPASS DRAINAGE. BMP DRAINAGE AREA: 0.71 AC TOTAL TURF: 0.10 AC HSG B: 0.04 AC HSG ❑: 0.06 AC IMPERV: 0.61 AC HSG B: 0.24 AC HSG D: 0.37 AC TOC: ASSUMED 5.0 MIN. BYPASS DRAINAGE AREA: 0.24 AC TOTAL ALL HSG B TURF: 0.20 AC IMPERV: 0.04 TOC: ASSUMED 5.0 MIN DRAINAGE TO POA 2: 0.19 AC. BYPASS DRAINAGE TURF: 0.13 AC HSG B: 0.07 AC HSG D: 0.06 AC IMPERV: 0.06 AC HSG B: 0.01 AC HSG ❑: 0.05 AC TOC: ASSUMED 5.0 MIN Energy Balance Equation Summary 2511 AVINITY DR 24 Hr 1 year Storm Comparison: Qdeveloped:�' I.F.*(Qpre-developed RVPre-❑eveloped)Rvdeveloped Qdeveloped:5 Qfarested RVforested RVdeveloped POA 1: Qpre-developed = 0.43 RVPre-Developed = 0.029 MaX Odeveloped = 0.26 cfs RVbeveloped = 0.043 Achieved Post-Dev Peak Runoff O1yr=4.24 cfs. Runoff complies with 9VAC25-870-66-(3)A 10-YEAR STORM: Qpre=1.89 cfs ❑post=1.35 cfs Energy Balance Equation Summary 2511 AVINITY DR 24 Hr 1 year Storm Comparison: Qdeveloped5 i•F• Qpre-developed RVPre-❑evefoped RVdeveloped Qdeveloped�5 Aorested RVfore sted RVdeveloped POA 2: Qpre-developed = 0.97 RVPre-Developed = 0.057 MAX Odeveloped = 0.97 cfs RVoeveloped = 0.019 Achieved Post-Dev Peak Runoff Qiyr=0.42 cfs. Runoff complies with 9VAC25-870-66-(3)A 10-YEAR STORM: Qpre=2.57 cfs Opost=1.13 cfs 2511 AVINITY DR Time of Concentration Calculations PREDEV TOO POA 1 100 ft overland flow 6.6% slope 0.35 C-value 10.1 min Seelye Chart 107 ft s. c. flow -woods 8.2% slope 2.0 fps velocity 0.9 min. NEH Figure 15-4 39 ft Channel 1.0 ft height 0.0 min. Kirpich Chart TOC= 11.0 min. I9:1 3 i}7 IVA lull" Zi71M 100 ft overland flow 5.6% slope 0.35 C-value 10.3 min Seelye Chart 119 ft s. c. flow -woods 6.5% slope 1.7 fps velocity 1.2 min. NEH Figure 15-4 58 ft Channel 2.0 ft height 0.2 min. Kirpich Chart TOC= 11.7 min. 30 Plived x 25 Q .8 3 00 c�7 9 Bore v 2 ❑ 200 Sol .. F W \SUrfpC! S AveQ .-0 , 0.5 YJ W o 90 Bo Dense \ a 20 H _ x t 70 Grass z \ 5 1- °— N� 60 c k 50 2 20 a w U 40 0 b 0 x 30 9 �w a 20 7 10 6 OVERLAND FLOW TIME {Scciyc Chart) hurce: Data Book for Cjv[[Enjinee F.F.• Seelp• Plate 5-1 V-11 TRAVEL TLW FOR CHANNEL FLAW [Kirpieh Chan] N ifmtl soo r� l.tp.1 zW 100 ICe L greet] Imoo so � 8 f to Ror ire •ith —L —n tc; f71 Ror pored r .L., . tlplr Y 10 to eE 6 moo R L_ ICU 1 TIME DP CMEENTRA?ION OF SHALL DRAIWE RPSINS Sntlrm VI)OT Plate 5.3 2511 AVINITY TGC NGIVIGGRAPHS Figure 15-4 Velocity V e]' m Slop' for Slmllnty now 1 0 �l�i����..11E EE El � � .11EEEElI �!li��E���l[■ EE E111•!! 'N ��ii�■t■■■[[AAAAII�ili !li��� ��� [[E EE ■ II ��f! iil�■■■■■ EII II I II ii•f�i I sii��■■■■■[[IElllli__ii i -■. ■■■��IIIIIIII �I�■ �' '' 'III■■1 { �� �:ME I�EII�� �� AI[EIEEIA�l� ��i [[AAAEAIA�AAi ii� 111lllllii ���■ 11111111� ��■■■ ■III11111��■ �■■ ��Illlllll��■ mom ;�111111111111Imms ■■■ 1 11111111111111■■i ■■_■-0001 ►1 _I_I_IIIIIIIIIIII_■■1 �C"Gi � AM ■mmENERE915111 AAAAAAAAIi/i i�■■■■■[[[A[All� nt oo � a ae .t ca e.c m ti m mo u� veloeity (f7s) LEGEND: RED: PREDEV TOC: POA 1 BLUE: PREDEV TQC: PGA 2 V - 13 PREDEV TO POA 1 Subcat Reach an Link i S PREDEV TO POA 2 Pre-Dev AVINITY PREDEV Type 1124-hr i-YR Rainfall=3.04" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CAM 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 2 Time span=1.00-36.00 hrs, dt=0.04 hrs, 876 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method 5ubcatchment 1S: PREDEV TO PQA 1 Runoff Area=0.610 ac 4.92% Impervious Runoff Depth=0.56" Tc=11.0 min CN=66 Runoff=0.43 cfs 0.029 of 5ubcatchment 2S: PREDEV TO PQA 2 Runoff Area=0.530 ac 13.21 % Impervious Runoff Depth=1.28" Tc=11.7 min CN=80 Runoff=0.97 cfs 0.057 of Total Runoff Area = 1.140 ac Runoff Volume = 0.085 of Average Runoff Depth = 0.90" 91.23% Pervious = 1.040 ac 8.77% Impervious = 0.100 ac Pre-Dev AVINITY PREDEV Type 1124-hr i-YR Rainfall=3.04" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment 1 S: PREDEV TO PQA 1 Runoff = 0.43 cfs @ 12.05 hrs, Volume= 0.029 af, ❑epth= 0.56" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-36.00 hrs, dt= 0.04 hrs Type If 24-hr 1-YR Rainfall=3.04" Area (ac) CN Description 0.490 61 >75% Grass cover, Goad, HSG B 0.090 80 >75% Grass cover, Goad, HSG D 0.030 98 Paved oarkina, HSG B 0.610 66 Weighted Average 0.580 95.08% Pervious Area 0.030 4.92% Impervious Area Tc Length Slope Velocity Capacity Description {min} (feet) (ftlft) (ftlsec) [cfs] 11.0 Direct Entry, Pre-Dev AVINITY PREDEV Type 1124-hr i-YR Rainfall=3.04" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment 2S: PREDEV TO PQA 2 Runoff = 0.97 cfs @ 12.04 hrs, Volume= 0.057 af, ❑epth= 1.28" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-36.00 hrs, dt= 0.04 hrs Type If 24-hr 1-YR Rainfall=3.04" Area (ac) CN Description 0.060 61 >75% Grass cover, Goad, HSG B 0.400 80 >75% Grass cover, Goad, HSG D 0.040 98 Paved parking, HSG B 0.030 98 Paved parking, HSG ❑ 0.530 80 Weighted Average 0.460 86.79% Pervious Area 0.070 13.21 % Impervious Area Tc Length Slope Velocity Capacity Description {min} (feet) (ftlft) (ftlsec) [cfs] 11.7 Direct Entry, Pre-Dev AVINITY PREDEV Type 1124-hr 10-YR Rainfall=5.56" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 HydroCADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 5 Time span=1.00-36.00 hrs, dt=0.04 hrs, 876 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method 5ubcatchment 1S: PREDEV TO PQA 1 Runoff Area=0.610 ac 4.92% Impervious Runoff Depth=2.12" Tc=11.0 min CN=66 Runoff=1.89 cfs 0.108 of 5ubcatchment 2S: PREDEV TO PQA 2 Runoff Area=0.530 ac 13.21 % Impervious Runoff Depth=3.39" Tc=11.7 min CN=80 Runoff=2.57 cfs 0.150 of Total Runoff Area = 1.144 ac Runoff Volume = 0.257 of Average Runoff Depth = 2.71" 91.23% Pervious = 1.040 ac 8.77% Impervious = 0.100 ac Pre-Dev AVINITY PREDEV Type 1124-hr 10-YR Rainfall=5.56" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 HydroCADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 6 Summary for Subcatchment 1 S: PREDEV TO PQA 1 Runoff = 1.89 cfs @ 12.03 hrs, Volume= 0.108 af, ❑epth= 2.12" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-36.00 hrs, dt= 0.04 hrs Type If 24-hr 10-YR Rainfall=5.56" Area (ac) CN Description 0.490 61 >75% Grass cover, Good, HSG B 0.090 80 >75% Grass cover, Good, HSG D 0.030 98 Paved oarkina, HSG B 0.610 66 Weighted Average 0.580 95.08% Pervious Area 0.030 4.92% Impervious Area Tc Length Slope Velocity Capacity Description {min} (feet) (ftlft) (ftlsec) [cfs] 11.0 Direct Entry, Pre-Dev AVINITY PREDEV Type 1124-hr 10-YR Rainfall=5.56" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 HydroCADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 7 Summary for Subcatchment 2S: PREDEV TO PQA 2 Runoff = 2.57 cfs @ 12.03 hrs, Volume= 0.150 af, ❑epth= 3.39" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-36.00 hrs, dt= 0.04 hrs Type If 24-hr 10-YR Rainfall=5.56" Area [ac] CN Description 0.060 61 >75% Grass cover, Good, HSG B 0.400 80 >75% Grass cover, Good, HSG D 0.040 98 Paved parking, HSG B 0.030 98 Paved parking, HSG ❑ 0.530 80 Weighted Average 0.460 86.79% Pervious Area 0.070 13.21 % Impervious Area Tc Length Slope Velocity Capacity Description {min} (feet) (ftlft) (ftlsec) [cfs] 11.7 Direct Entry, Pre-Dev AVINITY PREDEV Type 1124-hr 100-YR Rainfall=9.14" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CAM 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 8 Time span=1.00-36.00 hrs, dt=0.04 hrs, 876 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method 5ubcatchment 1S: PREDEV TO PQA 1 Runoff Area=0.610 ac 4.92% Impervious Runoff Depth=4.96" Tc=11.0 min CN=66 Runoff=4.46 cfs 0.252 of 5ubcatchment 2S: PREDEV TO PQA 2 Runoff Area=0.530 ac 13.21 % Impervious Runoff Depth=6.70" Tc=11.7 min CN=80 Runoff=4.94 cfs 0.296 of Total Runoff Area = 1.144 ac Runoff Volume = 0.548 of Average Runoff Depth = 5.77" 91.23% Pervious = 1.040 ac 8.77% Impervious = 0.100 ac Pre-Dev AVINITY PREDEV Type 1124-hr 100-YR Rainfall=9.14" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment 1 S: PREDEV TO PQA 1 Runoff = 4.46 cfs @ 12.03 hrs, Volume= 0.252 af, ❑epth= 4.96" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-36.00 hrs, dt= 0.04 hrs Type If 24-hr 100-YR Rainfall=9.14" Area (ac) CN Description 0.490 61 >75% Grass cover, Goad, HSG B 0.090 80 >75% Grass cover, Goad, HSG D 0.030 98 Paved oarkina, HSG B 0.610 66 Weighted Average 0.580 95.08% Pervious Area 0.030 4.92% Impervious Area Tc Length Slope Velocity Capacity Description {min} (feet) (ftlft) (ftlsec) [cfs] 11.0 Direct Entry, Pre-Dev AVINITY PREDEV Type 1124-hr 100-YR Rainfall=9.14" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 10 Summary for Subcatchment 2S: PREDEV TO PQA 2 Runoff = 4.94 cfs @ 12.03 hrs, Volume= 0.296 af, ❑epth= 6.70" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-36.00 hrs, dt= 0.04 hrs Type If 24-hr 100-YR Rainfall=9.14" Area (ac) CN Description 0.060 61 >75% Grass cover, Goad, HSG B 0.400 80 >75% Grass cover, Goad, HSG D 0.040 98 Paved parking, HSG B 0.030 98 Paved parking, HSG ❑ 0.530 80 Weighted Average 0.460 86.79% Pervious Area 0.070 13.21 % Impervious Area Tc Length Slope Velocity Capacity Description {min} (feet) (ftlft) (ftlsec) [cfs] 11.7 Direct Entry, 1S 2S 3S PGSTD V TO POSTDE BYPASS TO POSTDEV YPASS TO DETEN ION OA 1 P A 2 4P UNDERGR UN❑ 47 ❑ETENTION ork 5L 6L POA 1 POA 2 Subcat Reach an Link Drainage Diagram for AVINITY PQSTDEV Prepared by Shimp Engineering. P.C., Printed 1/15/2020 HydroGADO 9.10 sln 07054 (r) 2011 HydroCAD Software Solutions LLC Post-Dev AVINITY POSTDEV Type 1124-hr i-YR Rainfall=3.04" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 HvdroCADO 9.10 sln 07054 © 2011 HvdroCAD Software Solutions LLC Paoe 2 Time span=1.00-48.00 hrs, d1=0.04 hrs, 1176 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1S: POSTDEV TO Runoff Area=0.710 ac 85.92% Impervious Runoff Depth=2.39" Tc=5.0 mIn CN=94 Runoff=2.87 cfs 0.141 of Subcatchment 2S: POSTDEV BYPASS TO Runoff Area=0.240 ac 16.67% Impervious Runoff Depth=0.60" Tc=5.0 min CN=67 Runoff=0.24 cfs 0.012 of Subcatchment 3S: POSTDEV BYPASS TO Runoff Area=0.190 ac 31.58% Impervious Runoff Depth=1.22" Tc=5.0 min CN=79 Runoff=0.42 cfs 0.019 at Pont! 4P: UNDERGROUND DETENTION Peak Elev=532.15' Storage=0.116 of Inflow=2.87 cfs 0.141 of ❑utflow=0.05 cfs 0.031 of Link 5L: POA 1 Inflow=0.24 cfs 0,043 of Primary=0.24 cfs 0.043 of Link 6L: POA 2 Inflow=0.42 cfs 0.019 of Primary=0.42 cfs 0.019 of Total Runoff Area = 1.140 ac Runoff Volume = 0.173 of Average Runoff Depth = 1.82" 37.72% Pervious = 0.430 ac 62.28% Impervious = 0.710 ac Post-Dev AVINITY PQSTDEV Type 1124-hr i-YR Rainfall=3.04" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment IS: POSTDEV TO DETENTION Runoff = 2.87 cfs @ 11.96 hrs, Volume= 0.141 af, ❑epth= 2.39" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs. Type If 24-hr 1-YR Rainfall=3.04" Area (ac) CN Description 0.040 61 >75% Grass cover, Good, HSG B 0.060 80 >75% Grass cover, Good, HSG D 0.240 98 Paved parking, HSG B 0.370 98 Paved parking, HSG ❑ 0.710 94 Weighted Average 0.100 14.08% Pervious Area 0.610 85.92% Impervious Area Tc Length Slope Velocity Capacity Description {min} (feet) (ftlft) (ftlsec) [cfs] 5.0 Direct Entry, Post-Dev AVINITY PQSTDEV Type 1124-hr i-YR Rainfall=3.04" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment 2S: POSTDEV BYPASS TO POA 1 Runoff = 0.24 cfs @ 11.97 hrs, Volume= 0.012 af, ❑epth= 0.60" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs Type If 24-hr 1-YR Rainfall=3.04" Area (ac) CN Description 0.200 61 >75% Grass cover, Good, HSG B 0.040 98 Paved parking, HSG B 0.240 67 Weighted Average 0.200 83.33% Pervious Area 0.040 16.67% Impervious Area Tc Length Slope Veiocity Capacity Description {min} (feet) (ftlft) (ftlsec) [cfs] 5.0 Direct Entry, Post-Dev AVINITY PQSTDEV Type 1124-hr i-YR Rainfall=3.04" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment 3S: POSTDEV BYPASS TO POA 2 Runoff = 0.42 cfs @ 11.96 hrs, Volume= 0.019 af, ❑epth= 1.22" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs Type If 24-hr 1-YR Rainfall=3.04" Area (ac) CN Description 0.070 61 >75% Grass cover, Good, HSG B 0.060 80 >75% Grass cover, Good, HSG D 0.010 98 Paved parking, HSG B 0.050 98 Paved parking, HSG ❑ 0.190 79 Weighted Average 0.130 68.42% Pervious Area 0.060 31.58% Impervious Area Tc Length Slope Velocity Capacity Description {min} (feet) (ftlft) (ftlsec) [cfs] 5.0 Direct Entry, Post-Dev AVINITY POSTDEV Type 1124-hr i-YR Rainfall=3.04" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 6 Summary for Pond 4P: UNDERGROUND DETENTION (works) Inflow Area = 0.710 ac, 85.92% Impervious, Inflow Depth = 2.39" for 1-YR event Inflow = 2.87 cfs @ 11.96 hrs, Volume= 0.141 of Outflow = 0.05 cfs @ 16.05 hrs, Volume= 0.031 af, Atten= 98%, Lag= 245.7 min Primary = 0.05 cfs @ 16.05 hrs, Volume= 0.031 of Routing by Stor-Ind method, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs Peak Elev= 532.15' @ 16.05 hrs Surf.Area= 0.047 ac Storage= 0.116 of Plug -Flow detention time= 561.0 min calculated for 0.031 of (22% of inflow) Center -of -Mass det. time= 392.7 min ( 1,177.3 - 784.6 ) Volume Invert Avail.Storage Storage Description #1 528.00' 0.114 of 12.00'W x 172.00'L x 9.00'H Stone Bedding 0.426 of Overall - 0.141 of Embedded = 0.285 of x 40.0% Voids #2 529.00' 0.141 of 84.0" D x 160.01 Pipe Storage Inside #1 0.255 of Total Available Storage Device Routing Invert Outlet Devices #1 Primary 529.00' 15.0" Round Culvert L= 107.8' CMP, end -section conforming to fill, Ke= 0.500 Inlet 1 Outlet Invert= 529.00' 1 523.94' S= 0.0469 '1' Cc= 0.900 n= 0.012 #2 Device 1 532.00' 4.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 535.00' 4.9' long x 1.00' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 6.0' Crest Height Primary OutFlow Max=0.05 cfs @ 16.05 hrs HW=532.15' (Free Discharge) L1=Culvert (Passes 0.05 cfs of 9.38 cfs potential flow) T__2=Orif1ce/Grate (Orifice Controls 0.05 cfs C) 1.30 fps) 3=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) Post-Dev AVINITY PQSTDEV Type 1124-hr i-YR Rainfall=3.04" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 7 Summary for Link 5L: POA 1 Inflow Area = 0.950 ac, 68.42% Impervious, Inflow Depth = 0.54" for 1-YR event Inflow = 0.24 cfs @ 11.97 hrs, Volume= 0.043 of Primary = 0.24 cfs @ 11.97 hrs, Volume= 0.043 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs Post-Dev AVINITY PQSTDEV Type 1124-hr i-YR Rainfall=3.04" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 8 Summary for Link 6L: POA 2 Inflow Area = 0.190 ac, 31.58% Impervious, Inflow Depth = 1.22" for 1-YR event Inflow = 0.42 cfs @ 11.96 hrs, Volume= 0.019 of Primary = 0.42 cfs @ 11.98 hrs, Volume= 0.019 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs Post-Dev AVINITY POSTDEV Type 1124-hr 10-YR Rainfall=5.56" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 HvdroCADO 9.10 sln 07054 © 2011 HvdroCAD Software Solutions LLC Paoe 9 Time span=1.00-48.00 hrs, d1=0.04 hrs, 1176 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1S: POSTDEV TO Runoff Area=0.710 ac 85.92% Impervious Runoff Depth=4.86" Tc=5.0 min CN=94 Runoff=5.57 cfs 0.288 of Subcatchment 2S: POSTDEV BYPASS TO Runoff Area=0.240 ac 16.67% Impervious Runoff Depth=2.20" Tc=5.0 min CN=67 Runoff=0.97 cfs 0.044 of Subcatchment 3S: POSTDEV BYPASS TO Runoff Area=0.190 ac 31.58% Impervious Runoff Depth=3.29" Tc=5.0 min CN=79 Runoff=1.13 cfs 0.052 at Pont! 4P: UNDERGROUND DETENTION Peak Elev=533.91' Storage=0.175 of Inflow=5.57 cfs 0.288 of ❑utflow=0.55 cfs 0.177 of Link 5L: POA 1 Inflow=1.35 cfs 0,221 of Primary=1.35 cfs 0.221 of Link 6L: POA 2 Inflow=1.13 cfs 0.052 of Primary=1.13 cfs 0.052 of Total Runoff Area = 1.140 ac Runoff Volume = 0.384 of Average Runoff Depth = 4.04" 37.72% Pervious = 0.430 ac 62.28% Impervious = 0.710 ac Post-Dev AVINITY PQSTDEV Type 1124-hr 10-YR Rainfall=5.56" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 10 Summary for Subcatchment IS: POSTDEV TO DETENTION Runoff = 5.57 cfs @ 11.95 hrs, Volume= 0.288 af, ❑epth= 4.86" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs. Type If 24-hr 10-YR Rainfall=5.56" Area (ac) CN Description 0.040 61 >75% Grass cover, Good, HSG B 0.060 80 >75% Grass cover, Good, HSG D 0.240 98 Paved parking, HSG B 0.370 98 Paved parking, HSG ❑ 0.710 94 Weighted Average 0.100 14.08% Pervious Area 0.610 85.92% Impervious Area Tc Length Slope Velocity Capacity Description {min} (feet) (ftlft) (ftlsec) [cfs] 5.0 Direct Entry, Post-Dev AVINITY PQSTDEV Type 1124-hr 10-YR Rainfall=5.56" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 11 Summary for Subcatchment 2S: POSTDEV BYPASS TO POA 1 Runoff = 0.97 cfs @ 11.96 hrs, Volume= 0.044 af, ❑epth= 2.20" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs. Type If 24-hr 10-YR Rainfall=5.56" Area (ac) CN Description 0.200 61 >75% Grass cover, Good, HSG B 0.040 98 Paved parking, HSG B 0.240 67 Weighted Average 0.200 83.33% Pervious Area 0.040 16.67% Impervious Area Tc Length Slope Veiocity Capacity Description {min} (feet) (ftlft) (ftlsec) [cfs] 5.0 Direct Entry, Post-Dev AVINITY PQSTDEV Type 1124-hr 10-YR Rainfall=5.56" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 12 Summary for Subcatchment 3S: POSTDEV BYPASS TO POA 2 Runoff = 1.13 cfs @ 11.96 hrs, Volume= 0.052 af, ❑epth= 3.29" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs. Type If 24-hr 10-YR Rainfall=5.56" Area (ac) CN Description 0.070 61 >75% Grass cover, Good, HSG B 0.060 80 >75% Grass cover, Good, HSG D 0.010 98 Paved parking, HSG B 0.050 98 Paved parking, HSG ❑ 0.190 79 Weighted Average 0.130 68.42% Pervious Area 0.060 31.58% Impervious Area Tc Length Slope Velocity Capacity Description {min} (feet) (ftlft) (ftlsec) [cfs] 5.0 Direct Entry, Post-Dev AVINITY POSTDEV Type 1124-hr 10-YR Rainfall=5.56" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CAM 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 13 Summary for Pond 4P: UNDERGROUND DETENTION (works) Inflow Area = 0.710 ac, 85.92% Impervious, Inflow Depth = 4.86" for 10-YR event Inflow = 5.57 cfs @ 11.95 hrs, Volume= 0.288 of Outflow = 0.55 cfs @ 12.34 hrs, Vfllume= 0.177 af, Atten= 90%, Lag= 22.9 min Primary = 0.55 cfs @ 12.34 hrs, Volume= 0.177 of Routing by Stor-Ind method, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs Peak Elev= 533.91' @ 12.34 hrs Surf.Area= 0.047 ac Storage= 0.175 of Plug -Flow detention time= 261.3 min calculated for 0.177 of (62% of inflow) Center -of -Mass det. time= 156.8 min ( 922.9 - 766.0 ) Volume Invert Avail.Storage Storage Description #1 528.00' 0.114 of 12.00'W x 172.00'L x 9.00'H Stone Bedding 0.426 of Overall - 0.141 of Embedded = 0.285 of x 40.0% Voids #2 529.00' 0.141 of 84.0" D x 160.01 Pipe Storage Inside #1 0.255 of Total Available Storage Device Routing Invert Outlet Devices #1 Primary 529.00' 15.0" Round Culvert L= 107.8' CMP, end -section conforming to fill, Ke= 0.500 Inlet 1 Outlet Invert= 529.00' 1 523.94' S= 0.0469 '1' Cc= 0.900 n= 0.012 #2 Device 1 532.00' 4.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 535.00' 4.9' long x 1.00' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 6.0' Crest Height Primary OutFlow Max=0.55 cfs @ 12.34 hrs HW=533.91' (Free Discharge) L1=Culvert (Passes 0.55 cfs of 12.22 cfs potential flow) �2=Orif lce/G rate (Orifice Controls 0.55 cfs C) 6.35 fps) 3=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) Post-Dev AVINITY PQSTDEV Type 1124-hr 10-YR Rainfall=5.56" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 14 Summary for Link 5L: POA 1 Inflow Area = 0.950 ac, 68.42% Impervious, Inflow Depth = 2.79" for 10-YR event Inflow = 1.35 cfs @ 11.98 hrs, Volume= 0.221 of Primary = 1.35 cfs @ 11.98 hrs, Volume= 0.221 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs Post-Dev AVINITY PQSTDEV Type 1124-hr 10-YR Rainfall=5.56" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 15 Summary for Link 6L: POA 2 Inflow Area = 0.190 ac, 31.58% Impervious, Inflow Depth = 3.29" for 10-YR event Inflow = 1.13 cfs @ 11.96 hrs, Volume= 0.052 of Primary = 1.13 cfs @ 11.98 hrs, Volume= 0.052 af, Atten= O%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs Post-Dev AVINITY POSTDEV Type 1124-hr 100-YR Rainfall=9.14" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 HvdroCADO 9.10 sln 07054 © 2011 HvdroCAD Software Solutions LLC Paae 16 Time span=1.00-48.00 hrs, d1=0.04 hrs, 1176 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1S: POSTDEV TO Runoff Area=0.710 ac 85.92% Impervious Runoff Depth=8.42" Tc=5.0 min CN=94 Runoff=9.35 cfs 0.498 of Subcatchment 2S: POSTDEV BYPASS TO Runoff Area=0.240 ac 16.67% Impervious Runoff Depth=5r08" Tc=5.0 min CN=67 Runoff=2.21 cfs 0.102 of Subcatchment 3S: POSTDEV BYPASS TO Runoff Area=0.190 ac 31.58% Impervious Runoff Depth=6.58" Tc=5.0 min CN=79 Runoff=2.17 cfs 0.104 of Pont! 4P: UNDERGROUND DETENTION Peak Elev=535.63' Storage=0.228 of Inflow=9.35 cfs 0.498 of ❑utflow=8.71 cfs 0.387 of Link 5L: POA 1 Inflow=10.76 cfs 0.489 of Primary=10.76 cfs 0.489 of Link 6L: POA 2 Inflow=2.17 cfs 0.104 of Primary=2.17 cfs 0.104 of Total Runoff Area = 1.140 ac Runoff Volume = 0.704 of Average Runoff Depth = 7.41" 37.72% Pervious = 0.430 ac 62.28% Impervious = 0.710 ac Post-Dev AVINITY PQSTDEV Type 1124-hr 100-YR Rainfall=9.14" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 17 Summary for Subcatchment IS: POSTDEV TO DETENTION Runoff = 9.35 cfs @ 11.95 hrs, Volume= 0.498 af, ❑epth= 8.42" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs. Type If 24-hr 100-YR Rainfall=9.14" Area (ac) CN Description 0.040 61 >75% Grass cover, Good, HSG B 0.060 80 >75% Grass cover, Good, HSG D 0.240 98 Paved parking, HSG B 0.370 98 Paved parking, HSG ❑ 0.710 94 Weighted Average 0.100 14.08% Pervious Area 0.610 85.92% Impervious Area Tc Length Slope Velocity Capacity Description {min} (feet) (ftlft) (ftlsec) [cfs] 5.0 Direct Entry, Post-Dev AVINITY PQSTDEV Type 1124-hr 100-YR Rainfall=9.14" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 18 Summary for Subcatchment 2S: POSTDEV BYPASS TO POA 1 Runoff = 2.21 cfs @ 11.96 hrs, Volume= 0.102 af, ❑epth= 5.08" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs Type If 24-hr 100-YR Rainfall=9.14" Area (ac) CN Description 0.200 61 >75% Grass cover, Good, HSG B 0.040 98 Paved parking, HSG B 0.240 67 Weighted Average 0.200 83.33% Pervious Area 0.040 16.67% Impervious Area Tc Length Slope Veiocity Capacity Description {min} (feet) (ftlft) (ftlsec) [cfs] 5.0 Direct Entry, Post-Dev AVINITY PQSTDEV Type 1124-hr 100-YR Rainfall=9.14" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 19 Summary for Subcatchment 3S: POSTDEV BYPASS TO POA 2 Runoff = 2.17 cfs @ 11.96 hrs, Volume= 0.104 af, ❑epth= 6.58" Runoff by SCS TR-20 method, UH=SCS, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs. Type If 24-hr 100-YR Rainfall=9.14" Area (ac) CN Description 0.070 61 >75% Grass cover, Good, HSG B 0.060 80 >75% Grass cover, Good, HSG D 0.010 98 Paved parking, HSG B 0.050 98 Paved parking, HSG ❑ 0.190 79 Weighted Average 0.130 68.42% Pervious Area 0.060 31.58% Impervious Area Tc Length Slope Velocity Capacity Description {min} (feet) (ftlft) (ftlsec) [cfs] 5.0 Direct Entry, Post-Dev AVINITY POSTDEV Type 1124-hr 100-YR Rainfall=9.14" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CAM 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 20 Summary for Pond 4P: UNDERGROUND DETENTION (works) Inflow Area = 0.710 ac, 85.92% Impervious, Inflow Depth = 8.42" for 100-YR event Inflow = 9.35 cfs @ 11.95 hrs, Volume= 0.498 of Outflow = 8.71 cfs @ 11.99 hrs, Vfllume= 0.387 af, Atten= 7%, Lag= 2.1 min Primary = 8.71 cfs @ 11.99 hrs, Volume= 0.387 of Routing by Stor-Ind method, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs Peak Elev= 535.63' @ 11.99 hrs Surf.Area= 0.047 ac Storage= 0.228 of Plug -Flow detention time= 207.7 min calculated for 0.387 of (78% of inflow) Center -of -Mass det. time= 123.1 min ( 876.6 - 753.6 ) Volume Invert Avail.Storage Storage Description #1 528.00' 0.114 of 12.00'W x 172.00'L x 9.00'H Stone Bedding 0.426 of Overall - 0.141 of Embedded = 0.285 of x 40.0% Voids #2 529.00' 0.141 of 84.0" D x 160.01 Pipe Storage Inside #1 0.255 of Total Available Storage Device Routing Invert Outlet Devices #1 Primary 529.00' 15.0" Round Culvert L= 107.8' CMP, end -section conforming to fill, Ke= 0.500 Inlet 1 Outlet Invert= 529.00' 1 523.94' S= 0.0469 '1' Cc= 0.900 n= 0.012 #2 Device 1 532.00' 4.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 535.00' 4.9' long x 1.00' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 6.0' Crest Height Primary OutFlow Max=8.38 cfs @ 11.99 hrs HW=535.61' (Free Discharge) L1=Culvert (Passes 8.38 cfs of 14.46 cfs potential flow) �2=Orif lce/G rate (Orifice Controls 0.78 ofs C) 8.94 fps) 3=Sharp-Crested Rectangular Weir (Weir Controls 7.60 cfs @ 2.59 fps) Post-Dev AVINITY PQSTDEV Type 1124-hr 100-YR Rainfall=9.14" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 21 Summary for Link 5L: POA 1 Inflow Area = 0.950 ac, 68.42% Impervious, Inflow Depth = 6.18" for 100-YR event Inflow = 10.76 cfs @ 11.98 hrs, Volume= 0.489 of Primary = 10.76 cfs @ 11.98 hrs, Volume= 0.489 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs Post-Dev AVINITY PQSTDEV Type 1124-hr 100-YR Rainfall=9.14" Prepared by Shimp Engineering, P.C. Printed 1/15/2020 Hydro CADO 9.10 sln 07054 © 2011 HydroCAD Software Solutions LLC Page 22 Summary for Link 6L: POA 2 Inflow Area = 0.190 ac, 31.58% Impervious, Inflow Depth = 5.58" for 100-YR event Inflow = 2.17 cfs @ 11.96 hrs, Volume= 0.104 of Primary = 2.17 cfs @ 11.98 hrs, Volume= 0.104 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-48.00 hrs, dt= 0.04 hrs 2511 AVINITY DR In#et Drainage Area Summary Impervious C 0.9 Pervious C 0.3 To Inlet Area Imperious Turf C A C2 10,590 7,201 3,389 0.71 0.24 B2 19,540 13,287 6,253 0.71 0.45 X1 PRE 18,215 635 17,580 _� 0.32 1 0.42 X1 POST 5,990 1,060 4,930 0.41 0.14 X2 PRE 14,390 945 13,445 0.34 0.33 X2 POST 10,575 1,385 9,190 0.38 0.24 X3 PRE 5,445 2,100 3,345 0.53 0.13 X3 POST 5,340 1,020 4,320 0.41 0.12 X4 PRE 22,350 2,171 20,179 0.36 0.51 X4 POST 7,560 2,355 5,205 0.49 0.17 2511 AVINITY ❑R LD-204 Stormwater Inlet Computations Inlets on Grade Only Sag Inlets Only m E m m a N ¢` o a a m n O `m ti 9 U v n U `m ° o IR a m m t a w m a m °a -2 a U C] c- U O O ❑ a 0 ° cn C7m 3E ❑ ❑ za U ❑' A 1 2 3 4 5 6 8 9 10 11 12 13 14 15 16 17 18_1 19 1 20 21 22 23 24 (ft) (ac) (in.'hr) (cfs) (cis) lots) (''') (./.) ('i') (ft) (ft) (cis) (cfs] (ft) (It) (ft) C2 DI-3B 10 0.24 0.71 0.17 4.0 0-139 0.00 0.69 0-015 0.042 0.020 0-08 0.5 0.16 4.68 65 1-12 0.00 1.12 0.11 0.5 0-22 5-60 B2 DI-3B 10 0.45 0.71 0.32 4.0 1-27 0.00 1.27 0-015 0-015 0.020 0.12 0.5 0.24 5.91 6.5 2.06 0.00 2.05 0.16 0.5 0.33 8.15 X1 PRE DI-3B 12 0.42 0-32 0.13 4-0 0-54 0.00 0.54 65 0-87 0.00 0.87 X1 POST DI-30 12 0.14 0.41 0.06 4.0 0.22 0A) 0.22 6.5 0-36 0.00 0.36 x2 PRE DI-313 8 0.33 0.34 0.11 4.0 0.45 0.00 0.45 6-5 0-73 0.00 0.73 X2 POST DI-313 8 0.24 0-38 0.09 4.0 0.37 0.00 0.37 6-5 0-60 0.00 0.60 X3 PRE Di-3B 6 0.13 0-53 0.07 4.0 0-27 0.00 0.27 65 0-43 0.00 0.43 M POST Di-3C 6 0.12 0.41 0.05 4.0 0.20 0.00 0.20 6-5 0.33 0.00 0.33 X4 PRE DI-3B 6 0.51 0.36 0.18 4.0 0.74 0.00 0.74 65 1-19 0.00 1.19 X4 POST DI-313 6 0.17 0.49 0.08 4.0 0-34 0.00 0.34 6.5 0.55 0.00 0.55 Note: For existing inlets (x1 •X4), postdev runoff to the inlet is less than predev. No further analysis needed for these inlets or pipes. LD-229 Storm Drain Design Computations 2511 AVINITY DR From To Catch. Runoff Increment Accum. Total Total Total Up Down Pipe Invert Pipe Ripe Velocity Flow time Structure Structure Area Coe# AC AC TDC Intensity Flow Invert Invert Length Slope Diameter Capacity Increment ac) min inlhr cfs Elev. Elev. ft ❑/o in cfs ftls min 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 C2 C1 0.24 0.71 0.17 0.17 5.00 6.81 1.17 532.00 530.00 132.60 1.51❑% 15 8.6 4.9 0.45 B2 81 0,45 0.71 0.32 0.32 5,00 6.81 2.16 532.40 532.00 18.07 2,21% 15 10.4 6.7 0,04 A2' Al 0.55 529.00 525.94 107.81 2.84% 15 15.7 4.9 0.37 *10 yr Flow from H droCAD model Independent Reports: Excerpt from NRCS Soils Report NOAA Precipitation Report Precipitation Frequency Data Server https : //hds c. n w s. noaa. go v/hd se/pfd s/p fds_printpage. html?l at= 3 7.9 949&... NOAA Atlas 14, Volume 2, Version 3 Location name: Charlottesville, Virginia, USA" Latitude: 37.99491, Longitude:-78.5012, VE A) Elevation: 577.22 ft" source' ESRI M ps tiw source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES GM Bennin, D. Manin, B. Lin, T. Parzybok, M.Yekta, and D. Riley NQAk National Weather Service, Silver Spring, Maryland PF tabular I PF_graphical I Map s_&_aerials PF tabular PAS -based point precipitation frequency estimates with 90% confidence Intervals (in Inches)i Duration Average recurrence interval (years) 1 2 5 10 25 50 100 I 200 500 1000 Fs�mln]F0.352 p 416 p.48a p.557 0.fi2p 0.674 0.728 0.TT0 p.825 p.670 (0.317-0.391)(0.377-❑.465] (0.441-0.543) (0.495-0.610)(0.554-0.685) (0.600-0.743)1[0.641-0.798] (0.677-0.849) (0.719-0.912) (0.751-0.965) n10-mtn 0.562 [0_506-0_fi2_5_]iJ{0_603-0343] 0.669 0.784 (0-706.0.869] 0.881 (0.791-0.976) 0.988 1.07 1.15 1.22 (0_884-1.09) (0.956-1.18] (1.02-1.27] (1.07.1.35] 1.31 1 (1A4-1 44) 1.37 (1_18-1.52) 0.703 0.841 p.882 1.11 1.25 1.3fi 1.45 1.54 7.64 1.72 F15�inn] [0.632-0.781] (0.758-0.934) (0-893-1.10) (1.00 1.23} (1.12-1.38) (1.21-1.50) [1.29 i.60} F36 1.70] - [1.43-1.82] (1.48-1.91) 30-min 0.963 1.76 1.41 -[--i.fi7 1.8fi 2.05 2.23 2.40 2.61 2.79 11 F(2,40-3.09} [0.867.1.07) (1.05.1'29J (1.27.1.56) (1.45-1.79)1 (1,66.2-05) (1.82-2-26) [7.97.2-45] (2.11-2.65) (2.28-2.89) 1'20 1.46 1.81 2.10- 2.47 2.77 3.07 3.36 3.75 4.07 =60-min [t .08-1-34] (1-31-1,62) 1 (1-63-2-00) (1-89-2-33) 1 (2-21-2-73Y 1 (2.47-3-06) 11 (2-71-3-38) (2-96-3.71] (3.27-4-15) (3-51-4,51) - - - 2-hrF(l n7-1.85} 1.44 1.75 (1.53-1.99] 2.18 2.57 (1.92-2.49] {2.25 2.91 ) 3.06 3.4fi 3.88 (2.66 3.46) (3.00-3.92) (335 4.39) 4.31 [3.69 4.87] 4.91 (4.15-5.55) 5.40 (4.53-6.13) 1.58 1.91 2.39 2.80 3.34 3.79 4.25 4.T2 5.38 5.93 F-3-:hr:]F 0.38.1.82) J (1.67-2.19) 1 (2-08.234) 1 (2.44-3.21) 1 (2.89-3.82) 1 (3.27-4.32) 11 (3,64.4,84) i (4.02.5.39) (4.51-6.14) (4.93-6.78) 2.p2 2.43 3.02 3.56 4.27 4.80 5.5fi $.2fi 7.25 8.13 [:�hwr] [1.79-2.29] {2.15-2.76] (2.66 3.42} (3.12-4.D2} (3.72-4.83} (4.24 5.52] [4.76-6.26] - - [5.31 7.05] [6.06 8.18] - (6.70 9.17} - 12-hr 2.54 3.06 f 3.81 4.52 F 5.49 6.37 7.31 8.34 9.85 71.2 F [2.24.2.91] (2.70.3.50) (3.35-4.36) (3.8$-SA6) {4.78.6.25} (5.48-7.23) (6,21.8,28 (6.99.9.44) t8.10-11.2] .08-12.7j n 3.04 3.68 4.70 5.56 6.84 7.93 9.14 10.5 12.5 14.2 [2.73-3-41] (3-31-4.13) 1 (4-21-5.27) (4-97-6.22y 1 (6-06-7 61) (6.99 8-81] [7.98-10-1] (9.05-11-6) (10 6-13.8) 1 [11,9-15.7] 2-dey 3.58 4.34 [3.21 4.00] (3.90-4.86) 5.53 (4.95-6.17) 6.50 (5.80-7.25) 7.91 F(701-8.80] 9.10 (8.D7-10.1] 10.4 (9.07-11.5) 11.8 F(l0.2.13,1} 13.8 (11.8-15.4) 75.6 (13.1 17.4} 3.81 4.62 5.88 6.91 8.40 9.65 11.0 12.5 14.6 15.5 3-day (3.46-4-22) ( 4-20-5.12) (5-32-6.50) (6,24-7-63) (7-54-9.27) (8.61-10-8) (9.75-12.1) 1 (11-0-13.8) (12-7-16.2) 1 (14-1-18.2) 4.115 4.ep 6.22 8.88 1p.2 11.6.2 15.4 44ey (4.49-5.38] (5.70-6.83] F7.31 B.Oij {8.08-9.73) [9.22-11.2j [10.4-12.7] - [�-1-3 1.7-14.4j (13.6 17.0] 1-19.1] [�l7.3(3.71-4.44j 7-dey 4,70 � 566 7.07 8.24 9.91 11.3 144 16.7 786 F06-3-20A)8i (4.32 -51j (2.6.16] (6.50.770] {7-55896] (9.03.10-$j (10.2-12-313 15 ] 14.7-18.3) 10-day 4 5.33 6.39 ] _92 5.75} (5.92_fi_91 T.89- {7.3D=8.52] 9.11 (8-40 9-84] 10.8 } (9-94-11.7 ( 12.2 ] 11.2 13.2.i4-8 37 j [(1215-. (15317.5 13.8 16-5] (15-6 19.0] 19.4[ (171 21.1} 20-day F99 - 8.34 10.1 f 17.8 19 8 21.4 71.4 F 13.3 �-1 4.8 i 6.2 [6.56 7.48] (7.83-8.92) (9.44-10.8) 0.7-12.2} (12.4-14.2) (13.7-15.8) [75.0.17.4) (16.3-19.0] (18.1-21.3) (19.5-23.1) 3o-day�13] 1 (8. 8 (9.59- 0-8] _ (1f 3-12-8} (1263 4 -3} 6 (14-3 -3} 7 (156 -8]J [16� 9-2] (181� 0-7] 2.6] (20-7-24.1) 1 d.7 12.7 14.8 16.4 18.4 20.0 21.4 22.9 _(19fi� 4.7 26.0 [45-day]F (10.1-11.3} F(I.0-13.4] (14.0-15.7) [�l5.5-17.3} (17.4-19.5) (18.8-21.1) (20.1-22.7) (21.4-24,2) L230-26.3] 1 (24.1-27.8) so-dey 12.6 1-1-4.8-1 17.1 18.8 21.0 22.6 24.1 f 25.8 27A 28.8 ( 11 9 13.3} {14.0.15.6} (1$.2.18M) ( 19. 17-8-8) (19.8-22-1) ( 21-3.23-8) [223 25.4] ( 24.0-27.❑) [ 25.Fi 29.0] (2$.5-30.5) Precipitation frequency (PF) estimates in this table are based an frequency analysis of partial duration series (PD5). Numbers in parerrthesis are PF estimates at lower and upper bounds of the 90%confidence interval. The probability that precipitation frequency estimates [for a given duration and average recurrence interval] will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper hounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid P M P values. Please refer to NOAA Atlas 14 document far more information. Back to Top PF graphical 1 of 4 112/2020, 3:54 PM Precipitation Frequency Data Server https : //hds e. n w s. noaa. go v/hd se/pfd s/p fds_printpage. html?l at= 3 7.9 949&... M - ---•Charlottesville f til �isaHTlCt I Y Aw 3km 2mi Large scale terrain Washington D.C." . I-lanisanhur�l � 1 to un'.an VIrtic.INI A Rldmr—d Lynchburg Roanoke — SbVrq , .g 100km � r 1 semi ` N orfol Large scale map . 'E*risonlburg - - 5fa�lnron Lyncht L. 3lacksburg .,Roanoke 1ODkm 60mi Large scale aerial Nori[ 3 of 4 11212020, 3:54 PM USDA United States Department of Agriculture MRCS Natural Resources Conservation Service A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Albemarle County, Virginia October 3, 2019 Custom Soil Resource Report h Soil Map R � 37' SY 43' N 37' 59' 39- N /' = 71RA .. 71M TIM 7194M 719C20 1_ Map Scale: 1:911 1 printed on A landscape (I I" x BY) sheet. � N Meters 0 10 20 40 BO Feet 0 40 80 1e0 240 Map projeclbm Web Men.-:zW Coyne coordinates: WGS84 Edge tics: UTM ione 17N WGS84 9 71WO 7194W 7194W 719WO 719525 37' SY 43° N M 37' 54' 39" N Custom Soil Resource Report Map Unit Legend Map Unit Symbol Map Unit Name Acres in A01 Percent of A01 58B Myersville silt loam, 2 to 7 0.1 9.2% percent slopes 71 B Rabun clay loam, 2 to 7 percent 0.8 49.2% slopes 88 Udorthents, loamy, 2 to 25 0.7 41-6% percent slopes Totals for Area of Interest 1.6 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or 11 Custom Soil Resource Report Albemarle County, Virginia 58B—Myersville silt loam, 2 to 7 percent slopes Map Unit Setting National map unit symbol. kbcm Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: All areas are prime farmland Map Unit Composition Myersville and similar soils: 80 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Myersville Setting Landform: Interfluves Landform positron (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Convex Across -slope shape: Convex Parent material: Residuum weathered from greenstone Typical profile HT - 0 to 7 inches: silt loam H2 - 7 to 28 inches. silty clay loam H3 - 28 to 44 inches: silt loam H4 - 44 to 79 inches: bedrock Properties and qualities Slope: 2 to 7 percent Depth to restrictive feature: 40 to 60 inches to paralithic bedrock Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit wafer {Ksaf}: Very low to high (0.00 to 1.98 inlhr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 6.5 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2e Hydrologic Soil Group: B Hydric soil rating: No 13 Custom Soil Resource Report 71 B—Rabun clay loam, 2 to 7 percent slopes Map Unit Setting National map unit symbol: 2xxyl Elevation: 360 to 1,540 feet Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees 1= Frost -free period: 195 to 231 days Farmland classification: All areas are prime farmland Map Unit Composition Rabun and similar soils: 80 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Rabun Setting Landform: I nterfluves Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Convex Across -slope shape: Convex Parent material: Residuum weathered from greenstone Typical profile A - 0 to 6 inches: clay loam Bt - 6 to 48 inches: clay C - 48 to 79 inches: silty clay loam Properties and qualities Slope: 2 to 7 percent Depth to restrictive feature: More than 89 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit wafer (Ksat): Moderately high to high (0.57 to 1.98 inlhr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 8.7 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2e Hydrologic Soil Group: B Hydric soil rating: N❑ 14 Custom Soil Resource Report 88—Udorthents, loamy, 2 t❑ 25 percent slopes Map Unit Setting National map unit symbol: 2xxz3 Elevation: 360 to 1,540 feet Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost -free period: 195 to 231 days Farmland classification: Not prime farmland Map Unit Composition Udorthents and similar soils: 85 percent Minor components: 5 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Udorthents Setting Landform: I nterfluves Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down -slope shape: Convex Across -slope shape: Convex Parent material: Residuum weathered from granite and gneiss Properties and qualities Slope: 2 to 25 percent Depth to restrictive feature: More than 80 inches Depth to water table: More than 80 inches Frequency of flooding: None Frequency ofponding: None Minor Components Hatboro, occasionally flooded Percent of map unit: 5 percent Landform: Flood plains Down -slope shape: Linear Across -slope shape: linear Hydric soil rating: Yes IN