Loading...
HomeMy WebLinkAboutWPO201500033 Calculations 2020-03-09 SHIMP ENGINEERING, P.C. Design Focused Engineering Hilibrook Subdivision 3-5-2020 As-Built SWM Calculations APPROVED by the Albemarle County Community D velopment Department Date D c ?o File - fr r,' a e4 STIN S �. Lic. •.45183 w S' ICNAT SHIMP ENGINEERING, P.C. Design Focused Engineering March 5th, 2020 Frank Pohl County Engineer Albemarle County Department of Community Development Regarding: WPO 201500033 Hillbrook Subdivision SWM As-Built Analysis Dear Mr. Pohl, Please find attached a summary of the As-Built SWM Analysis for the Hillbrook Subdivision. An error in analysis of the detention drainage area has been found. The originally proposed detention drainage area included approximately 0.31 acres of both on-site and off-site area that is not actually being detained. The attached documents provide an analysis of the "As-Built"conditions for the site and for the additional included drainage areas. The energy balance equation has been reanalyzed at a new POA, located at the existing channel at the outlet of the STM X2 storm structure. This POA includes the additional areas shown on the attached Pre and Post Dev SWM Total DA Maps. The Post Development DA Map for on-site has been revised to describe the as-built drainage areas being either detained or not detained. The TOC and HydroCAD models have been revised to reflect the as-built drainage areas, showing both on-site and off-site areas not being detained. Please see the attached Asbuilt Drainage Area Map for a summary of the flows, including percentage of increase/decrease from predevelopment. Also included are Hydracids models for Predevelopment, As-built and an As-built Amendment. Total volume to the POA is increased by only 0.014 acre-feet from predevelopment conditions. Flow to the POA will be reduced at much as possible by decreasing the as-built 5-inch 1-year orifice to a diameter or 2-inches. While the energy balance equation was not met with the as-built condition, the post-development 1-yr and 10-yr flows show a minor increase and the 2-yr flow will be decreased after amending the 1-yr orifice to 2-inches. It was noted before construction of the Hillbrook subdivision that the existing channel receiving the flows was already showing signs of erosion. The current channel condition does not appear to show signs that erosion has increased since construction of the Hillbrook subdivision. For these reasons, the receiving channel will have minimal increased risk of flooding or erosion. We believe that the increase in runoff generated by the as-built conditions will be within an acceptable range for the watershed in my judgement as a professional engineer; and that the runoff will have no negative effect on the SWM channels in the area. If you have any questions please do not hesitate to contact me at Justin@shimp-engineering.com or by phone at 434-227-5140. zest R:gards, I J Shimp S p Engineering, P.C. Contents: Pre-Development Calculations: Pre-Dev Drainage Map Pre-Dev Storm Total DA Map Pre-Dev HydroCAD Report Energy Balance Equation Summary As-Built Runoff Quantity Calculations: As-Built Drainage Map As-Built Total DA Map As-Built Post-Dev HydroCAD Report As-Built Amended Post-Dev HydroCAD Report Runoff Quality Calculations: VRRM New Development Spreadsheet Pre-Development Calculations: Pre-Dev Drainage Map Pre-Dev Storm Total DA Map Pre-Dev HydroCAD Report Energy Balance Equation Summary / / /I i i \ \ / i i \ 1/ /1---i/ I \\, HILL300 < �/ /� i / 1 \1 PREDEV STORM TOTAL DA MAP I I �/ SleialiA II \ 1 I I I \ 1\ \ IMPERVIOUS / I . , // ___---- 1, _. , ��� -- r ��♦♦♦♦��, (1 \ 1 / / / ( 1 ` 1.....„... \ N \ \ N\ I / ��♦♦!� 1 \ I I / I I ' 'I \ ____N \N I V> i i 1 . \1 / � lr► 1 I \ ` \ SIT M *.- ' I q,'' 1--- - { - r ( \ , _ -4 4. 1 1 I «dew 1 / \ \ \ \ I /0 7, ,.!.4:47400 t_Wril i ,i ) / / / . y / kare4 z ' 4 \ I / II i I 4 1 I 4 \ / ,► \ 1 / \ \ / 4•110 ' '4 ot . \ , , l ti► / ►♦♦90—4, 11r, A -a 1 # " J / \ \ • / i ' 44 P -4.11) // / , %/* .„ / \ \ -. N - 11 / // li* 4 I 0"b AI.. ) wi, ___ / \— — \ \ ' .0411 I , ..,i. 4 I- 1 \ ilel \ V V % ,047 i # l' ,-ril ' • i f V ' . tillott \ 111h4. t .41111419101111111111ffir irlit‘ TIVM k*:eft:4 ‘ ,7 7 \ \ \ TNEX2 D A -Nov 4/ ' 4* 0.119 ` . \ �:, ,$I4;4 ,,,i1<_c, , ,,; 1 \ I t \ ' f54 AO k 1 • --- ''' ,k )144,41 i V — * '- ' r \ I \ ) /1 \ \ II ‘\ ' ' '' '' ' 447i . 1 j if 4111// if ' "* ' '.110VOCAlll, . . N: \ 1 \ \ 1 / / / /� � / �R " / !/'�� � i< .�« fllf / '' � � _ Al 1 \ \ \ \ V A\ \ A I\ \ r/ // r �' �� Cf aII d y/ / �//l // /1 r1�llli1 i li / / 1\ \ \ \ 111 \ \ 1 1 1 J/ / r j//'�/�/ , II.'lll�'I / 1 ' \\ \ \ \ \ \ \ \ 111�y 7 /O � i i ✓/. / I1t.IfllI / 1 \ \ \ \ \ \ 1 1>/ ' / / /' /I °r� i.n�ji + �� \ \ \ I I ,'//r / / (��I , 'IIIt!I.I 1 ` \ \ \ \ \ \ \ < < I 1 _ I Wel i'r,..41, Iio 1 I 11. It i ; \ ' \ \ \ \ ' \ 1 ) ) 1 i )- _ , _, -,- ...., ....._ ...., . , . k Air,;Ail! II li \ \ \ \ \ \ I I / / / 1 I 2 / / ? orit�C rat,I i• 2 ONSIT� I,,,, ..--__,-__ , --,,,,-,-,-P ,.•-"..- 1.' '-44 1,,,,', 'Ili]ii(-11 \ \ `, \ \ \ \ \ 1 \, 1 \ 1 ? ) p I / , v 0.3 ,'P�vg.h 11{ I.568 AC. % l \ 1 I / / ; / . //// . \\ / / / :w°NV*1"' k itcFs ♦ / i 1 1 I i 1 / I l /�1lii/ l/ \ / // 1.1 \ / \V / ♦ x� `t •\\0 \_ I 1 I I \ \\ . lip 7' Ilk 1,4fr ro „/ \ \ \ \ \ 1 / / / \\ , / - -- / - \ 4, \ra ( 1 I 1 1 / r \ •.� \ I I ` � � 1 / / / / / \ \ \ \\' • ' \ , II I (Spill 2 1 I 1 y \ / / / 1 1 \ . / \ \ \ \ \ • \ " I � 1 I \` \ \ —f / / 111 //' _ — -- -\\ \\ \\ \\ \`\�� \\ \ 11 1\ \\ I \ \ \ \ \ \ \\ \ \ \ \ ! i v \ It \ I 1 \''d.--- 4 0 __ — \ \ \\ . ''1' \ \ ( / , / %e . / 80 _ _ 0 80 160 240 1 / 1 // L _ / / — — \\ �, /,%/// /_ �� :w \\ �� Scale 1"=80' / /' / // / / . t / ',°� / / - - - - z , / / / / ;-' / 1 / ii , z L� 00 � j _ _iz z / / / / / // x � PRE—DEVELOPMENT SWM MAP/ / / / i l z / � _ 'NJ/ '\ c' \ �/ / / / / / / � /l/l/ / �� / / / / / / _ o ,....._ , / / / / / i/ T14z % : \ / // // _ "Ii N. - - - / / / f:i Al 11 Hi/0i,- , --r ...'-----\ \ I MOM // / , ►�// // // / ,/ \ / e5. , �� 1 �l /l/// l//// _ � 1 .�4� ,Ill - v I , ��� \ I �I ° ....., ,.... /'/1 % „ llli,li p, //' `\ \ , , .... ...-- - i 1 ' — ►. III/ / / A \ I I ;j `� -- / I - . I 1111111111 / z \ Y . 1 i - �� f/'�� /i / fi/l / I \ I� ` , �l/l//Il/� 1 1 I i 11 i � Ipiii l/y l l j i I I I I '� j if ll�ll j I lio ' III ! 1 I I I ; �.� r ! j 1 < ,. � �' 111 IIIII \ I I I �I �� � � 1 , I \ 1 ; ; 1 \41 ��4 � 411 , ! 1. 1, 1, 1 II 1 \ \ \ \ \ � � j 4. �`,►1 111 1 I \ \ \ \ i 1 \\ \~ _ ' 3ii cilia 11 � 1I I \ i \411*- 1 f) 14 \ \ , #7 Oa 328 I 0 44L+4.41, I II • 2 Oimstarik 1 \ 014) ' 4 " 1 (A i1111.4., \ I vA*14IP i L. l 1 °21 CF > ► / �� T �� �' '4,, - ttw A.A ,I I1 s , I I l l / I �' i ......, % / • \ 1 \ \ / AA * , I 1 \ \ ✓ ' / ! IMPERVIOUS ii* . ��\ \\\ \--- - J ( _ _...... _ 8,� , \ / / Area 1 Time of Concentration } ,� \ //� , slope Seelye Chart / r I ' 200 ft overland flow 7 7% P 0 35 C—value 13 2 min Y \ ` • / / \ 1 128 ft s c flow—woods 8 2% slope 1 4 fps velocity 1 4 min NEH Figure 15-4 - - \ \ ` 4* �, C/(0. \\\ , I 14.6 min. \ \ ,1 \ \ Area 2 Time of Concentration \ \ \ \* V S * �\ _ — - J - ` \ 1 88 ft overland flow 10 3% slope 0.35 C—value 9 1 min Seelye Chart \ \ \ \\ �` \ \\ \:), \ \\ \\ ' /1 223 ft Swale 12 ft height 0 3 mm Kirpich Chart \ A / — \ \ \\ \ \ ‘ f \ 1 / 9.4 min. i L \----- \ \ \ .o �, 1 I j j 40 _ 0 40 80 120 � ✓ Scale: 1"=40' \ \, \ \ \ 1 \ \, '/ / 1 A' I Hillbrook Pre-Development Time of Concentration Calculations DA 2 Onsite 091 ft overland flow 11.0% slope 0.35 C—value 8.4 min Seelye Chart 311 ft s. c. flow 5 8% slope 4.8 fps velocity 1.1 min. NEH Figure 15-4 158 ft channel 12 ft height 1.1 min. Kirpich Chart 10.6 min. DA 2 Offsite 080 ft overland flow 7.5% slope 0.35 C—value 9.4 min Seelye Chart 244 ft s. c flow 5.3% slope 4.5 fps velocity 0.9 min. NEH Figure 15-4 55 ft channel 8 ft height 0.2 min Kirpich Chart 10.5 min. STM X2A 153 ft overland flow 5 3% slope 0.35 C—value 11.5 min Seelye Chart 298 ft s. c flow 8.0% slope 5.6 fps velocity 0.9 min. NEH Figure 15-4 242 ft channel 20 ft height 0.9 min. Kirpich Chart 13.3 min. STM X3 162 ft overland flow 13.6% slope 0.35 C—value 10.2 min Seelye Chart 38 ft s. c. flow 4.0% slope 4.0 fps velocity 0.2 min. NEH Figure 15-4 97 ft channel 12 ft height 0.5 min. Kirpich Chart 10.9 min. Energy Balance Equation Summary Shimp Engineering, P.C. 3/4/2020 24 Hr 1 year Storm: POA 1 Qn developed5I.F• Qpre-developed RVPre-Developed)/Redeveloped Qdeveloped� (Qforested*RVforested)/Redeveloped Drainage Area : 4.477 Ac Qpre-developed = 5.56 RVpre-Developed = 0.347 Max Qdeveloped = 4.28 cfs RVDeveloped = 0.361 Post Development Runoff Peak Flow =5.67 cfs, Does Not Meet 9VAC25-870-66-B(3) Post Development Q10= 17.66 cfs RV Increase= 0.014 ac/ft Hillbrook Pre-Development HydroCAD Report (16S) X A <18S> 17S X3 X2 `N 4 POA 3 D.A.2 Offsite D.A.2 Onsite Subcat Reach 'on. Link Drainage Diagram for Hillbrook Pre-Development ASBUILT REV Prepared by Shimp Engineering, Printed 1/30/2020 HydroCAD®9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC PREDEVELOPMENT HYDROCAD Hil!brook Pre-Development ASBUILT REV Type 11 24-hr 1yr Rainfall=3.01" Prepared by Shimp Engineering Printed 1/30/2020 HydroCADO 9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Page 2 Time span=0.00-24.00 hrs,dt=0.01 hrs, 2401 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment2: D.A.2 Onsite Runoff Area=0.568 ac 0.00%Impervious Runoff Depth>0.37" Tc=10.6 min CN=61 Runoff=0.21 cfs 0.017 af Subcatchment3:D.A.2 Offsite Runoff Area=0.510 ac 64.31%Impervious Runoff Depth>1.59" Tc=10.5 min CN=85 Runoff=1.23 cfs 0.068 af Subcatchment 16S:X2A Runoff Area=1.550 ac 34.58%Impervious Runoff Depth>0.91" Tc=13.3 min CN=74 Runoff=1.86 cfs 0.118 of Subcatchment 17S:X2 Runoff Area=0.190 ac 81.05%Impervious Runoff Depth>2.08" Tc=5.0 min CN=91 Runoff=0.70 cfs 0.033 af Subcatchment 18S:X3 Runoff Area=1.390 ac 37.05%Impervious Runoff Depth>0.96" Tc=10.9 min CN=75 Runoff=1.95 cfs 0.112 af Link 4:POA Inflow=5.56 cfs 0.347 af Primary=5.56 cfs 0.347 af Total Runoff Area=4.208 ac Runoff Volume=0.347 af Average Runoff Depth=0.99" 63.57% Pervious=2.675 ac 36.43%Impervious=1.533 ac PREDEVELOPMENT HYDROCAD Hilibrook Pre-Development ASBUILT REV Type II 24-hr 1yr Rainfall=3.01" Prepared by Shimp Engineering Printed 1/30/2020 HydroCAD®9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment 2: D.A.2 Onsite Runoff = 0.21 cfs @ 12.06 hrs, Volume= 0.017 af, Depth> 0.37" Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs,dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description 0.568 61 Pasture/grassland/range, Good, HSG B 0.568 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.6 Direct Entry, Summary for Subcatchment 3: D.A.2 Offsite Runoff = 1.23 cfs @ 12.02 hrs, Volume= 0.068 af, Depth> 1.59" Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs, dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description 0.182 61 Pasture/grassland/range, Good, HSG B * 0.328 98 Impervious 0.510 85 Weighted Average 0.182 35.69%Pervious Area 0.328 64.31% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.5 Direct Entry, Summary for Subcatchment 16S: X2A Runoff = 1.86 cfs @ 12.06 hrs, Volume= 0.118 af, Depth> 0.91" Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs,dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description * 0.536 98 IMPERVIOUS * 1.014 61 Turf 1.550 74 Weighted Average 1.014 65.42%Pervious Area 0.536 34.58%Impervious Area PREDEVELOPMENT HYDROCAD Hil!brook Pre-Development ASBUILT REV Type 1I 24-hr 1yr Rainfall=3.01" Prepared by Shimp Engineering Printed 1/30/2020 HydroCAD®9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Page 4 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.3 Direct Entry, Summary for Subcatchment 17S: X2 Runoff = 0.70 cfs @ 11.96 hrs, Volume= 0.033 af, Depth> 2,08" Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs,dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description * 0.154 98 IMPERVIOUS * 0.036 61 Turf 0.190 91 Weighted Average 0,036 18.95%Pervious Area 0.154 81.05% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 18S: X3 Runoff = 1.95 cfs @ 12.03 hrs, Volume= 0.112 af, Depth> 0.96" Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs, dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description * 0.515 98 IMPERVIOUS * 0.875 61 Turf 1.390 75 Weighted Average 0.875 62.95%Pervious Area 0,515 37.05%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.9 Direct Entry, Summary for Link 4: POA Inflow Area= 4.208 ac, 36.43%Impervious, Inflow Depth> 0.99" for 1yr event Inflow = 5.56 cfs @ 12.03 hrs, Volume= 0.347 of Primary = 5.56 cfs @ 12.03 hrs, Volume= 0.347 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-24.00 hrs, dt=0.01 hrs PREDEVELOPMENT HYDROCAD Hillbrook Pre-Development ASBUILT REV Type II 24-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 1/30/2020 HydroCAD®9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Page 5 Time span=0.00-24.00 hrs,dt=0.01 hrs, 2401 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 2: D.A.2 Onsite Runoff Area=0.568 ac 0.00% Impervious Runoff Depth>0.64" Tc=10.6 min CN=61 Runoff=0.46 cfs 0.030 of Subcatchment 3: D.A.2 Offsite Runoff Area=0.510 ac 64.31% Impervious Runoff Depth>2.14" Tc=10.5 min CN=85 Runoff=1.65 cfs 0.091 af Subcatchment16S:X2A Runoff Area=1.550 ac 34.58% Impervious Runoff Depth>1.34" Tc=13.3 min CN=74 Runoff=2.81 cfs 0.173 af Subcatchment 17S:X2 Runoff Area=0.190 ac 81.05%Impervious Runoff Depth>2.68" Tc=5.0 min CN=91 Runoff=0.89 cfs 0.042 af Subcatchment 18S:X3 Runoff Area=1.390 ac 37.05%Impervious Runoff Depth>1.40" Tc=10.9 min CN=75 Runoff=2.90 cfs 0.163 of Link 4:POA Inflow=8.22 cfs 0.499 of Primary=8.22 cfs 0.499 af Total Runoff Area=4.208 ac Runoff Volume=0.499 af Average Runoff Depth =1.42" 63.57%Pervious=2.675 ac 36.43%Impervious=1.533 ac PREDEVELOPMENT HYDROCAD Hilibrook Pre-Development ASBUILT REV Type II 24-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 1/30/2020 HydroCAD®9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Page 6 Summary for Subcatchment 2: D.A.2 Onsite Runoff = 0.46 cfs @ 12.05 hrs, Volume= 0.030 af, Depth> 0.64" Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs, dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description 0.568 61 Pasture/grassland/range, Good, HSG B 0.568 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.6 Direct Entry, Summary for Subcatchment 3: D.A.2 Offsite Runoff = 1.65 cfs @ 12.02 hrs, Volume= 0.091 af, Depth> 2.14" Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs, dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description 0.182 61 Pasture/grassland/range, Good, HSG B * 0.328 98 Impervious 0.510 85 Weighted Average 0.182 35.69%Pervious Area 0.328 64.31% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.5 Direct Entry, Summary for Subcatchment 16S: X2A Runoff = 2.81 cfs @ 12.06 hrs, Volume= 0.173 af, Depth> 1.34" Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs, dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description • 0.536 98 IMPERVIOUS • 1.014 61 Turf 1.550 74 Weighted Average 1.014 65.42%Pervious Area 0.536 34.58% Impervious Area PREDEVELOPMENT HYDROCAD Hillbrook Pre-Development ASBUILT REV Type II 24-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 1/30/2020 HydroCAD®9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Page 7 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.3 Direct Entry, Summary for Subcatchment 17S: X2 Runoff = 0.89 cfs @ 11.96 hrs, Volume= 0.042 af, Depth> 2.68" Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description * 0.154 98 IMPERVIOUS * 0.036 61 Turf 0.190 91 Weighted Average 0.036 18.95% Pervious Area 0.154 81.05% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 18S: X3 Runoff = 2.90 cfs @ 12.03 hrs, Volume= 0.163 af, Depth> 1.40" Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description * 0.515 98 IMPERVIOUS * 0.875 61 Turf 1.390 75 Weighted Average 0.875 62.95%Pervious Area 0.515 37.05% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.9 Direct Entry, Summary for Link 4: POA Inflow Area= 4.208 ac, 36.43%Impervious, Inflow Depth> 1.42" for 2yr event Inflow = 8.22 cfs @ 12.03 hrs, Volume= 0.499 af Primary = 8.22 cfs @ 12.03 hrs, Volume= 0.499 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-24.00 hrs, dt=0.01 hrs PREDEVELOPMENT HYDROCAD Hil!brook Pre-Development ASBUILT REV Type 1124-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 1/30/2020 HydroCAD®9.10 sin 07054 0 2010 HydroCAD Software Solutions LLC Page 8 Time span=0.00-24.00 hrs,dt=0.01 hrs, 2401 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment2: D.A.2 Onsite Runoff Area=0.568 ac 0.00%Impervious Runoff Depth>1.68" Tc=10.6 min CN=61 Runoff=1.40 cfs 0.079 af Subcatchment3: D.A.2 Offsite Runoff Area=0.510 ac 64.31%Impervious Runoff Depth>3.83" Tc=10.5 min CN=85 Runoff=2.88 cfs 0.163 af Subcatchment 16S:X2A Runoff Area=1.550 ac 34.58%Impervious Runoff Depth>2.77" Tc=13.3 min CN=74 Runoff=5.91 cfs 0.357 of Subcatchment 17S:X2 Runoff Area=0.190 ac 81.05% Impervious Runoff Depth>4.47" Tc=5.0 min CN=91 Runoff=1.44 cfs 0.071 of Subcatchment 18S:X3 Runoff Area=1.390 ac 37.05% Impervious Runoff Depth>2.86" Tc=10.9 min CN=75 Runoff=5.95 cfs 0.331 of Link 4:POA Inflow=16.83 cfs 1.002 af Pnmary=16.83 cfs 1.002 of Total Runoff Area=4.208 ac Runoff Volume=1.002 af Average Runoff Depth=2.86" 63.57% Pervious=2.675 ac 36.43%Impervious=1.533 ac PREDEVELOPMENT HYDROCAD Hillbrook Pre-Development ASBUILT REV Type II 24-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 1/30/2020 HydroCAD®9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment 2: D.A.2 Onsite Runoff = 1.40 cfs @ 12.03 hrs, Volume= 0.079 af, Depth> 1.68" Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description 0.568 61 Pasture/grassland/range, Good, HSG B 0.568 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.6 Direct Entry, Summary for Subcatchment 3: D.A.2 Offsite Runoff = 2.88 cfs @ 12.02 hrs, Volume= 0.163 af, Depth> 3.83" Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs, dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description 0.182 61 Pasture/grassland/range, Good, HSG B * 0.328 98 Impervious 0.510 85 Weighted Average 0.182 35.69% Pervious Area 0.328 64,31% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.5 Direct Entry, Summary for Subcatchment 16S: X2A Runoff = 5.91 cfs @ 12.05 hrs, Volume= 0.357 af, Depth> 2.77" Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description * 0.536 98 IMPERVIOUS * 1.014 61 Turf 1.550 74 Weighted Average 1.014 65.42%Pervious Area 0.536 34.58% Impervious Area PREDEVELOPMENT HYDROCAD Hil!brook Pre-Development ASBUILT REV Type II 24-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 1/30/2020 HydroCAD®9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Page 10 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.3 Direct Entry, Summary for Subcatchment 17S: X2 Runoff = 1.44 cfs @ 11,96 hrs, Volume= 0.071 at Depth> 4.47" Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs, dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description * 0.154 98 IMPERVIOUS * 0.036 61 Turf 0.190 91 Weighted Average 0.036 18.95% Pervious Area 0.154 81.05% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 18S: X3 Runoff = 5.95 cfs @ 12.03 hrs, Volume= 0.331 af, Depth> 2.86" Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description * 0.515 98 IMPERVIOUS * 0.875 61 Turf 1.390 75 Weighted Average 0.875 62.95% Pervious Area 0.515 37.05% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.9 Direct Entry, Summary for Link 4: POA Inflow Area= 4.208 ac, 36.43%Impervious, Inflow Depth> 2.86" for 10yr event Inflow = 16,83 cfs @ 12,03 hrs, Volume= 1.002 af Primary = 16,83 cfs @ 12.03 hrs, Volume= 1.002 at Atten=0%, Lag=0.0 min Primary outflow= Inflow, Time Span=0.00-24.00 hrs, dt=0.01 hrs As-Built Runoff Quantity Calculations: As-Built Drainage Map As-Built Total DA Map As-Built Post-Dev HydroCAD Report As-Built Amended Post-Dev HydroCAD Report � � , 1i i { i 1 i I \\, HILL300K / �'� 1 J� \1 POST DEV TOTAL STORM DA MAP / \ / 1 it / , Al I 1 1 r \ 1 I \ IMPERVIOUS / / I ��\ 1 A' �,�� / \ NCI. . �.� +�+�� ` \ I I / / ' \ ` ` - \1 \ t \ 1 \,..._-----\ , 1, , 0-- , , \ _ . , \ \ , , • \ \ AS M - vt. : i-- I \ \ ;• / 1 .55/ A 6,;�;: rigral ) /' ) 14.1-. , \ , \ \ 1 P'' '.- - -; , ., / / // ow • 7\ .-S, \ - -vrlir. t el- 1\ \ \ / \ • \ �` � \ �\ � I //;IA;A t \ I i \ • \\ N\ * I .tk1p4:' li // 1 \ \ --\ \.._ fr / pi l ' - l'--,7/ I / / / \ < � �\ N . ' 7 // \1 OP -.- i`�/0 / I t+fir, ♦ 1 1 \ ..„! e:., 1 IkP ' . , 4), v1 , '♦ ' / l 1 \ ' -Ar - - - -TM \X2Di ��t4/irc ., 9 ,` E • . .. L \) \ \, . Vo sir47.44:'.4",..;-. :1 c.'1 ,T, I 7 \ L l 154AO - \ 'Ai44#4,. '% % - - 'N 0 \ ` 1 \ \EA*tAIV r 1 ,r3s\ ) / \ I '--... --, ri 4 . i,f '. -4* , <2" ' 1 • ` 1 I /!_ �, . �.. \ \% . It �� . \ \ ( • MICI / y If P• " / / / ^ l 441 �s \ \ \ \ \ \ A rll iI ___ , .„--• 1 .1' 6' ' ,' -1-iiiiii-- I* I so ' \ \ 1 ) ) I I )._, ....., • ___..... \ 0, v 1.\,*.:c.., .. #(40:-Po - -.. 1 \ - .t:2-,•- / , /. .*••.„ ,,,, , :/) \ \/\ \i; :i /\i \//,/,' ./,''''' I\ ' / \ / Illap.' 'kV' AI 1* ‘ ' . • ,..41 ' r, ... / \ 0 / -t r kl:' — , A iti&A. . ' ‘,' \ I \ " \ / ../ ---11 V.,Y -V -gAiiiii 'AI I . / /.. / \ \ 4 , ........„ ..... _.\ ,...‘ N_Iti ,,,,,,,,6,.., ......., ___. . . . • 4\ Ae: Illik .k, I ( ' 1 ( illIN I / ipipiii > \ _ / , CRITICAL SLOPES \ \\ I SEE SWM POST DEV DA MAP , f � i / \ \ \ '\ \ .\\\ ' \{ \ \ j I \ / \ \ \ \ \ \ ` . \ . / \ \ t ,i, \ \ . \ \ ,,, , - i = { \ \ �� f �� fr — — ,, {{ \ \ l ( �5 1 r ,� 80 - - - 0 80 160 240 \ -- ' 1 \ \ ///// , / - \ L - - -'4, \ % \ Scale: 1"=80' / / I I/ //// ,, ' - - - $ -SfTE DETAINED — , °� I ON-SI E / i ' AC. — — � �� _ _ ' — — \iI' - 4// *// X ;O. 9 ( h I LLBf�00K ,NOT DETAINS (2) F: / I ��/ 0.0 AC. IMP. \ I . - a/ l / VA y, , I I AS-BUILT SWM MAP 0.16 AC. �► �- ,1 . , '. W W W`- y W.- W W W W W W W .y W 'Y W W / R A SI 0-1,Z. 0.054 A . IMP. W W W / W W W W W W W W W * * * �� A .��/�/��/ / . * y W W W W W W W W , -• • , q * Predevelopment / / I/// �� W v. W \W `\y �(. W W I■ 6-:440 * Q pre developed 5.56 I%�� //��,J// .t 1 .► J�/Qy'rV��/� W W \.� W81i1 �� W .r W pre-developed OFFSITE r * A,,,n 0 �i, // W W W D.At : �' W , 0 0 # 0 Q pre-developed 16.83 NOT DETAINED (2 #, < I��1 i''' . /./t/i x W *40 .A 4 4 ; .. 1. W W ` 4 * 0• Asbuilt `r.,4It I 'r I� W . , W W W f. J ` 0.328 AO 14 tI NI Oil* . ��I/ r CO rA �� r * °lir I Q post developed 5.78 I ;r/ � 0.208 AC. IM I / rIlI I�I /W � \� W ` W / W / IW Hkk.:7* WIQ2post-developed - 8. •`�11 L I l 1 (Y�"�-, t r �� ''� I II rI II W W y biA \.. W W W`W W W V',, \ ,_\ ` ,- 0 I QlOpost_leveloped — 16.93 K * / ., a ♦,, t / I I I \ l ,1111 z \ I 'IS�i W W W I W 1 \ W \ h 1► 4 �'�i W W �� 1 / a 4 \ I� 00 Amended Asbuilt C ' ek J©� W 1T/ -1I. \ ! 0 0\0 (�'� -\. w.. W \Y 5 I \{LPO PEd -W W W W) ,y� W ll W W 1 W* * :\* ` W ` Q1Opost-developed = 17.66 . ill y e X W W W W �, •W W W W W W _ 0 4, Storm Change Y W W W '� ► I �k , 1 c 4 I� • �- ' W W Wiii W W � W W \ ��� js� %Change 4. "W * * * ti4V Iy111 ^ . / W W W * * W \ Q1 0.11 2.0% W W W W W —;.-,\,` ��0-�,�.,.� .+ /// / �' * *\ * W W W I `[2 _O.UY ZI.S% ,j4' W W W W\ W W 1 . } /II:i � _. .I1 f \ W W `.,,,,www � .y .y \ * * W . W W 1 ' ��• ` /. � W W ' (..,� , * W/, W 4 I Q10 0.83 4.9% gi� I 1 \ K i � �� e�� �i f� � ` **° °OAyOP*1 AS—BUILT AMENDED VALUES SHOWN W W W y W . _ W ' l W W p Y W W \ vipir .4.1k i IY I J W 'Y W �W W W y �, W\ ,.. i 4. • / H S G B 1 W Y `1{ . II�� ,� Or `� '� W � Y W1W W W W\ W W 1 I ,y. ) I / / �1\ - , I -- .,� PRESERVED z0z 0 `* W * /W D-A A W \ r W WOODS 1 \ ♦t 'Y\ W \ / , O' W W + ' l W W _ 0 � A r W/ i_ WONSITE NOT W 1 * * W W Atli; $ W Energy Balance MANAGED Y W W . W Y W . DETAINED 1 /, 4` � W W W 11 W W W W (W W W I.F. 0.8 LAWN WWWWWWWW ( .si 4, �_�_ • * * * L 1 W ..\W W W W W Ji W W W W II W 0.15 AC. W W W \ W W 'V• ' W W I W W W W! Qpre 5.56 cfs Ite\*4#4t W WY0000e W W W W Y0.0 AC. IMP. W . W W\ I IMPERVIOUS iv 1 -�---JWW t W W RV,. 0.347 ac—ft1 a W W W I ) RVdw 0.361 ac—ft 4, W I 1 _ OFFSITE NOT iv W ��W\ W AI • •YWWWWyWWWW WW * WWW` 1 / I Q.. 4.28 cfs SIMPLE I DISCONNECTION O DETAINED (1 )\ \ _ _ _ — _ --L _ _ I ORIG IAL SHEET A A Jj \W r--- _ FLOW AREA I // SWM DIVIDE NIB = Ell — 0.16AC. , , 0 , � W O 0.14. AC. IMP. '�‘ �‘W 0.246 C. TOTAL / STORM DIVIDE , \ \ W �� \ ToC=1 I .6 MIN.; / l 1� $�� � — SIMPLE 40 0 40 80 120 Qi-0.1 CF� i i REVISED: 3-5-2020 DISCONNECTIONDIVIDE 1 ' ■ ■ ■ ■ ■ \ 1 • Scale: 1"=40' / n Hillbrook Post-Development Time of Concentration Calculations STM X2A 153 ft overland flow 5.3% slope 0.35 C-value 11.5 min Seelye Chart 298 ft s. c flow 8 0% slope 5 6 fps velocity 0.9 min NEH Figure 15-4 242 ft channel 20 ft height 0 9 min. Kirpich Chart 13.3 min. STM X3 162 ft overland flow 13 6% slope 0.35 C-value 10.2 min Seelye Chart 38 ft s. c. flow 4 0% slope 4.0 fps velocity 0.2 min. NEH Figure 15-4 97 ft channel 12 ft height 0 5 min. Kirpich Chart 10.9 min. Onsite Not Detained (1) 100 ft overland flow 8 0% slope 0.35 C-value 9.6 min Seelye Chart 175 ft s c. flow 8.0% slope 1.3 fps velocity 2.2 min. NEH Figure 15-4 284 ft channel 15 ft height 1.7 min. Kirpich Chart 13.5 min Offsite Not Detained (1) 045 ft overland flow 0 5% slope 0.35 C-value 3.0 min Seelye Chart 220 ft s. c. flow 5.5% slope 1.3 fps velocity 2.8 min NEH Figure 15-4 284 ft channel 15 ft height 1 7 min Kirpich Chart 7.5 min Offsite Not Detained (2) 070 ft overland flow 3 0% slope 0.35 C-value 1.0 min Seelye Chart 205 ft s. c flow 5.0% slope 1 0 fps velocity 3 4 min. NEH Figure 15-4 284 ft channel 12 ft height 1.7 min. Kirpich Chart 6.1 min. Onsite Not Detained (2) 052 ft overland flow 40 0% slope 0.35 C-value 5 0 min Seelye Chart 90 ft s c. flow 6 6% slope 5.0 fps velocity 0 3 min. NEH Figure 15-4 284 ft channel 12 ft height 1.7 min. Kirpich Chart 7.0 min Onsite Detained 050 ft overland flow 16.0% slope 0.35 C-value 9.5 min Seelye Chart 18 ft s. c. flow 1 0% slope 1.0 fps velocity 0.3 min NEH Figure 15-4 300 ft channel 15 ft height 2.2 min. Kirpich Chart 12 0 min. Hillbrook As-Built HydroCAD Report Revised: 3-5-2020 - (us) (17S) X3 OtTSite Not Detained O (2) D A.B(Ne Sheetflow) 12S .--\_. O O' nal Sheetflow Area ( 8) ^ 10 D A ��OnSite Not Detained14L(2) ill ��Strea Head 040A Q - -A *A Flow at Open Space Dete wn Vault Detention Onsite Not Detained(1) (13S) (6 \ (14s) /) Watershed DA Offsite Not Detained(1) Onsite Detained (Subca) Reach Pon Link Drainage Diagram for HILLBROOK ASBUILT POSTDEV HYDROCAD ----\\/ Prepared by{enter your company name here). Printed 1/30/2020 HydroCAD®9.10 s/n 07054 ©2011 HydroCAD Software Solutions LLC ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 1 yr Rainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 2 Time span=0.00-48.00 hrs, dt=0.01 hrs,4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Intl+Trans method - Pond routing by Stor-Ind method Subcatchment 1: D.A.B(New Sheetflow) Runoff Area=0.240 ac 0.00%Impervious Runoff Depth=0.91" Tc=11.6 min CN=74 Runoff=0.31 cfs 0.018 af Subcatchment 2: D.A.A Runoff Area=0.99 ac 0.00% Impervi s Runoff Depth=1.08" Tc=1 . = unoff=1.63 cfs 0.089 of Subcatchment 5:Onsite Not Detained(1) Runoff Area=0.150 ac 0.00%Impervious Runoff Depth=0.37" Tc=13.5 min CN=61 Runoff=0.05 cfs 0.005 af Subcatchment 6:Offsite Not Detained(1) Runoff Area=0.160 ac 87.50%Impervious Runoff Depth=2.26" Tc=7.5 min CN=93 Runoff=0.58 cfs 0.030 of Subcatchment 8:On-Site Not Detained(2) Runoff Area=0.169 ac 31.95%Impervious Runoff Depth=0.86" Tc=7.0 min CN=73 Runoff=0.25 cfs 0.012 af Subcatchment 9:Off-Site Not Detained(2) Runoff Area=0.328 ac 63.41%Impervious Runoff Depth=1.52" Tc=6.1 min CN=84 Runoff=0.89 cfs 0.042 af Subcatchment 12S:Original SheetflowArea Runoff Area=0.800 ac 0.00%Impervious Runoff Depth=0.25" Tc=11.6 min CN=57 Runoff=0.13 cfs 0.017 of Subcatchment 13S:Watershed DA Runoff Area=7.700 ac 57.14%Impervious Runoff Depth=1.39" Tc=17.0 min CN=82 Runoff=12.92 cfs 0.890 of Subcatchment 14S:Onsite Detained Runoff Area=0.190 ac 31.58% Impervious Runoff Depth=0.86" Tc=12.0 min CN=73 Runoff=0.22 cfs 0.014 af Subcatchment 15S:X2A Runoff Area=1.550 ac 34.58%Impervious Runoff Depth=0.91" Tc=13.3 min CN=74 Runoff=1.86 cfs 0.118 of Subcatchment 16S:X2 Runoff Area=0.190 ac 81.05% Impervious Runoff Depth=2.08" Tc=5.0 min CN=91 Runoff=0.70 cfs 0.033 af Subcatchment 17S:X3 Runoff Area=1.330 ac 38.72%Impervious Runoff Depth=0.97" Tc=10.9 min CN=75 Runoff=1.87 cfs 0.107 of Pond 3:Vault Peak Elev=496.81' Storage=9 cf Inflow=1.63 cfs 0.089 of Pnmary=1.63 cfs 0.089 of Secondary=0.00 cfs 0.000 af Outflow=1.63 cfs 0.089 of Pond 4:Detention Peak Elev=491.39' Storage=1,692 cf Inflow=1.63 cfs 0.089 af Outflow=0.13 cfs 0.089 af Pond 7: Detention Peak Elev=490.06' Storage=0 cf Inflow=0.22 cfs 0.014 of Outflow=0.22 cfs 0.014 af Link 10:POA Inflow=5.78 cfs 0.361 of Primary=5.78 cfs 0.361 of ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 1 yr Rainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 3 Link 11:Flow at Open Space Inflow=0.53 cfs 0.124 af Primary=0.53 cfs 0.124 af Link 14L:Stream Head Inflow=12.92 cfs 0.890 of Primary=12.92 cfs 0.890 of Total Runoff Area=13.797 ac Runoff Volume=1.374 af Average Runoff Depth=1.20" 56.03%Pervious=7.730 ac 43.97%Impervious=6.067 ac ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type II 24-hr lyrRainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment 1: D.A. B (New Sheetflow) Runoff = 0.31 cfs @ 12.05 hrs, Volume= 0.018 af, Depth= 0,91" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48,00 hrs, dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description * 0.240 74 Sheet Flow Adjusted CN 0.240 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.6 Direct Entry, Summary for Subcatchment 2: D.A.A Runoff = 1.63 cfs @ 12.02 hrs, Volume= 0.089 af, Depth= 1.08" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description * 0.990 77 Adjusted CN 0.990 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Subcatchment 5: Onsite Not Detained (1) Runoff = 0.05 cfs @ 12.10 hrs, Volume= 0.005 af, Depth= 0.37" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description 0.150 61 >75%Grass cover,Good, HSG B 0.150 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.5 Direct Entry, ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr lyrRainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment 6: Offsite Not Detained (1) Runoff = 0.58 cfs @ 11.99 hrs, Volume= 0.030 af, Depth= 2.26" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 1 yr Rainfall=3.01" Area(ac) CN Description * 0.140 98 Impervious 0.020 61 >75%Grass cover,Good, HSG B 0.160 93 Weighted Average 0.020 12.50%Pervious Area 0.140 87.50% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.5 Direct Entry, Summary for Subcatchment 8: On-Site Not Detained (2) Runoff = 0,25 cfs @ 11.99 hrs, Volume= 0.012 af, Depth= 0.86" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 1 yr Rainfall=3.01" Area(ac) CN Description 0.115 61 >75%Grass cover, Good, HSG B * 0.054 98 Impervious 0.169 73 Weighted Average 0.115 68.05%Pervious Area 0.054 31.95% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment 9: Off-Site Not Detained (2) Runoff = 0.89 cfs @ 11.98 hrs, Volume= 0.042 af, Depth= 1.52" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description 0.120 61 >75%Grass cover, Good, HSG B * 0.208 98 Impervious 0.328 84 Weighted Average 0.120 36.59%Pervious Area 0.208 63.41%Impervious Area ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 1 yr Rainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 6 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.1 Direct Entry, Summary for Subcatchment 12S: Original Sheetflow Area Runoff = 0.13 cfs @ 12.09 hrs, Volume= 0.017 af, Depth= 0.25" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description 0.246 61 >75%Grass cover,Good, HSG B 0.554 55 Woods, Good, HSG B 0.800 57 Weighted Average 0.800 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.6 Direct Entry, Summary for Subcatchment 13S: Watershed DA Runoff = 12.92 cfs @ 12.10 hrs, Volume= 0.890 af, Depth= 1.39" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description * 3.300 61 Turf * 4.400 98 Impervious 7.700 82 Weighted Average 3.300 42.86%Pervious Area 4.400 57.14%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.0 Direct Entry, Summary for Subcatchment 14S: Onsite Detained Runoff = 0.22 cfs @ 12.05 hrs, Volume= 0.014 af, Depth= 0.86" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 1 yr Rainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 7 Area(ac) CN Description * 0.060 98 Impervious 0.130 61 >75%Grass cover,Good, HSG B 0.190 73 Weighted Average 0.130 68.42%Pervious Area 0.060 31.58%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.0 Direct Entry, Summary for Subcatchment 15S: X2A Runoff = 1.86 cfs@ 12.06 hrs, Volume= 0.118 af, Depth= 0.91" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description * 0.536 98 IMPERVIOUS * 1.014 61 Turf 1.550 74 Weighted Average 1.014 65.42%Pervious Area 0.536 34.58%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13,3 Direct Entry, Summary for Subcatchment 16S: X2 Runoff = 0.70 cfs @ 11.96 hrs, Volume= 0.033 af, Depth= 2.08" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description * 0.154 98 IMPERVIOUS * 0.036 61 Turf 0.190 91 Weighted Average 0.036 18.95%Pervious Area 0.154 81.05% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type II 24-hr lyrRainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment 17S: X3 Runoff = 1.87 cfs @ 12.03 hrs, Volume= 0.107 af, Depth= 0.97" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description * 0.515 98 IMPERVIOUS * 0.815 61 Turf 1.330 75 Weighted Average 0.815 61.28%Pervious Area 0.515 38.72%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.9 Direct Entry, Summary for Pond 3: Vault Inflow Area= 0.990 ac, 0.00%Impervious, Inflow Depth= 1.08" for 1yr event Inflow = 1.63 cfs @ 12.02 hrs, Volume= 0.089 of Outflow = 1.63 cfs @ 12.03 hrs, Volume= 0.089 af, Atten=0%, Lag=0.1 min Primary = 1.63 cfs @ 12.03 hrs, Volume= 0.089 af Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Routing by Stor-Ind method,Time Span=0.00-48.00 hrs,dt=0.01 hrs Peak Elev=496.81'@ 12.03 hrs Surf.Area= 16 sf Storage=9 cf Plug-Flow detention time=0.2 min calculated for 0.089 af(100%of inflow) Center-of-Mass det.time=0.2 min (856.4-856.3) Volume Invert Avail.Storage Storage Description #1 496.23' 98 cf 4.00'W x 4.00'L x 6.12'H 4'x4'Vault Storage Device Routing Invert Outlet Devices #1 Primary 496.17' 15.0" Round STM 5-6 L= 182.9' Ke=0.100 Inlet/Outlet Invert=496.17'1494.80' S=0.00757 Cc=0.900 n=0.011, Flow Area= 1.23 sf #2 Device 1 496.23' 24.0"W x 3.0" H Vert.Weir Plate Orifice C=0.600 Limited to weir flow at low heads #3 Secondary 497.33' 15.0" Round STM 3-4 L=69.1' Ke=0.100 Inlet/Outlet Invert=497.33'/490.18' S=0.1035'1 Cc=0.900 n=0.011, Flow Area= 1.23 sf #4 Device 3 496.24' 15.0" Round STM 4-5 L= 15.7' Ke=0.100 Inlet/Outlet Invert=496.19'/496.24' S=-0.0032'/' Cc=0.900 n=0.011, Flow Area= 1.23 sf ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type II 24-hr lyrRainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 9 Primary OutFlow Max=1.62 cfs@ 12.03 hrs HW=496.81' (Free Discharge) L1=STM 5-6 (Passes 1.62 cfs of 1.94 cfs potential flow) L2=Weir Plate Orifice (Orifice Controls 1.62 cfs @ 3.25 fps) Secondary OutFlow Max=0.00 cfs@ 0.00 hrs HW=496.23' (Free Discharge) L3=STM 3-4 (Controls 0.00 cfs) L4=STM 4-5 (Controls 0.00 cfs) Summary for Pond 4: Detention Inflow Area= 0.990 ac, 0.00%Impervious, Inflow Depth= 1.08" for 1 yr event Inflow = 1.63 cfs @ 12.03 hrs, Volume= 0.089 of Outflow = 0.13 cfs @ 12.97 hrs, Volume= 0.089 af, Atten=92%, Lag=56.9 min Primary = 0.13 cfs @ 12.97 hrs, Volume= 0.089 af Routing by Stor-Ind method,Time Span=0.00-48.00 hrs, dt=0.01 hrs Peak Elev=491.39'@ 12.97 hrs Surf.Area= 1,714 sf Storage= 1,692 cf Plug-Flow detention time=149.8 min calculated for 0,089 af(100%of inflow) Center-of-Mass det.time=149.8 min( 1,006.2-856.4) Volume Invert Avail.Storage Storage Description #1 489.70' 2,936 cf Gravel(Prismatic)Listed below(Recalc) 9,256 cf Overall- 1,917 cf Embedded=7,339 cf x 40.0%Voids #2 489.70' 1,917 cf StormTech MC-4500 x 18 Inside#1 Effective Size=90.4"W x 60.0"H =>26.46 sf x 4.03'L= 106.5 cf Overall Size= 100.0"W x 60.0"H x 4.33'L with 0.31' Overlap 4,852 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 489.70 1,714 0 0 495.10 1,714 9,256 9,256 Device Routing Invert Outlet Devices #1 Primary 494.25' 32.0'long x 3.7'breadth Emergency Spillway Head(feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef.(English) 2.40 2.55 2.69 2.68 2.66 2.66 2.65 2.67 2.67 2.69 2.75 2.79 2.82 2.87 3.01 3.14 3.32 #2 Primary 489.70' 3.0" Round Culvert L= 110.0' Ke=0.800 Inlet/Outlet Invert=489.70'/488.00' S=0.0155'/' Cc=0.900 n=0.015, Flow Area=0.05 sf Primary OutFlow Max=0.13 cfs@ 12.97 hrs HW=491.39' (Free Discharge) L1=Emergency Spillway (Controls 0.00 cfs) 2=Culvert (Barrel Controls 0.13 cfs @ 2.56 fps) ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 11 24-hr 1 yr Rainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD010.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 10 Summary for Pond 7: Detention Inflow Area= 0.190 ac, 31.58%Impervious, Inflow Depth= 0.86" for 1 yr event Inflow = 0.22 cfs @ 12.05 hrs, Volume= 0.014 af Outflow = 0.22 cfs @ 12.05 hrs, Volume= 0.014 af, Atten=0%, Lag=0.0 min Primary = 0.22 cfs @ 12.05 hrs, Volume= 0.014 af Routing by Stor-Ind method,Time Span=0.00-48.00 hrs, dt=0.01 hrs Peak Elev=490.06'@ 12.05 hrs Surf.Area= 1 sf Storage=0 cf Plug-Flow detention time=0.0 min calculated for 0.014 af(100%of inflow) Center-of-Mass det.time=0.0 min(871.8-871.8) Volume Invert Avail.Storage Storage Description #1 490.03' 29 cf 15.0" Round 15"Storage L=23.4' S=0.0098'/' #2 490.26' 1,433 cf 48.0" Round 48"Storage x 3 L=38.0' S=0.0025'/' 1,461 cf Total Available Storage Device Routing Invert Outlet Devices #1 Primary 489.33' 15.0" Round Pipe 2-1 L= 123.9' Ke=0.600 Inlet/Outlet Invert=489.33'/482.35' S=0.05631' Cc=0.900 n=0,011, Flow Area= 1.23 sf #2 Device 1 489.53' 5.0"Vert. 1-yr Orifice C=0.600 Limited to weir flow at low heads #3 Device 1 491.93' 48.0"W x 5.0"H Vert. 10-yr Orifice C=0.600 Limited to weir flow at low heads Primary OutFlow Max=0.37 cfs@ 12.05 hrs HW=490.06' (Free Discharge) L1=Pipe 2-1 (Passes 0.37 cfs of 2.01 cfs potential flow) 12=1-yr Orifice (Orifice Controls 0.37 cfs @ 2.71 fps) 3=10-yr Orifice (Controls 0.00 cfs) Summary for Link 10: POA Inflow Area= 4.067 ac, 40.99%Impervious, Inflow Depth = 1.06" for 1yr event Inflow = 5.78 cfs @ 12.01 hrs, Volume= 0.361 af Primary = 5.78 cfs @ 12.01 hrs, Volume= 0.361 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow, Time Span=0.00-48.00 hrs, dt=0.01 hrs Summary for Link 11: Flow at Open Space Inflow Area= 2.030 ac, 0.00%Impervious, Inflow Depth = 0.73" for 1 yr event Inflow = 0.53 cfs @ 12.06 hrs, Volume= 0.124 af Primary = 0.53 cfs @ 12.06 hrs, Volume= 0.124 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-48.00 hrs, dt=0.01 hrs ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 1 yr Rainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 11 Summary for Link 14L: Stream Head Inflow Area= 7.700 ac, 57.14%Impervious, Inflow Depth= 1.39" for 1 yr event Inflow = 12,92 cfs @ 12.10 hrs, Volume= 0.890 af Primary = 12,92 cfs @ 12.10 hrs, Volume= 0.890 af, Atten=0%, Lag=0.0 min Primary outflow=Inflow,Time Span=0,00-48.00 hrs,dt=0.01 hrs ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 12 Time span=0.00-48.00 hrs,dt=0.01 hrs,4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1: D.A.B(New Sheetflow) Runoff Area=0.240 ac 0.00% Impervious Runoff Depth=1.34" Tc=11.6 min CN=74 Runoff=0.46 cfs 0.027 of Subcatchment2:D.A.A Runoff Area=0.990 ac 0.00%Impervious Runoff Depth=1.54" Tc=10.0 min CN=77 Runoff=2.35 cfs 0.127 af Subcatchment 5:Onsite Not Detained(1) Runoff Area=0.150 ac 0.00% Impervious Runoff Depth=0.64" Tc=13.5 min CN=61 Runoff=0.11 cfs 0.008 of Subcatchment 6:Offsite Not Detained(1) Runoff Area=0.160 ac 87.50%Impervious Runoff Depth=2.88" Tc=7.5 min CN=93 Runoff=0.73 cfs 0.038 of Subcatchment 8:On-Site Not Detained(2) Runoff Area=0.169 ac 31.95% Impervious Runoff Depth=1.28" Tc=7.0 min CN=73 Runoff=0.37 cfs 0.018 af Subcatchment 9:Off-Site Not Detained(2) Runoff Area=0.328 ac 63.41%Impervious Runoff Depth=2.07" Tc=6.1 min CN=84 Runoff=1.19 cfs 0.056 of Subcatchment 12S:Original Sheetflow Area Runoff Area=0.800 ac 0.00%Impervious Runoff Depth=0.47" Tc=11 6 min CN=57 Runoff=0 38 cfs 0.032 of Subcatchment 13S:Watershed DA Runoff Area=7.700 ac 57.14% Impervious Runoff Depth=1.91" Tc=17.0 min CN=82 Runoff=17.86 cfs 1.224 of Subcatchment 14S:Onsite Detained Runoff Area=0.190 ac 31.58%Impervious Runoff Depth=1.28" Tc=12.0 min CN=73 Runoff=0.34 cfs 0.020 af Subcatchment 15S:X2A Runoff Area=1.550 ac 34.58%Impervious Runoff Depth=1.34" Tc=13.3 min CN=74 Runoff=2.81 cfs 0.174 of Subcatchment 16S:X2 Runoff Area=0.190 ac 81.05% Impervious Runoff Depth=2.68" Tc=5.0 min CN=91 Runoff=0.89 cfs 0.042 af Subcatchment 17S:X3 Runoff Area=1.330 ac 38.72%Impervious Runoff Depth=1.41" Tc=10.9 min CN=75 Runoff=2.78 cfs 0.156 of Pond 3:Vault Peak Elev=497.31 Storage=17 cf Inflow=2.35 cfs 0.127 af Primary=2.35 cfs 0.127 of Secondary=0.00 cfs 0.000 of Outflow=2.35 cfs 0.127 af Pond 4: Detention Peak Elev=492.42' Storage=2,673 cf Inflow=2.35 cfs 0.127 af Outflow=0.14 cfs 0.127 of Pond 7:Detention Peak Elev=490.07' Storage=0 cf Inflow=0.34 cfs 0.020 of Outflow=0.34 cfs 0.020 af Link 10:POA Inflow=8.40 cfs 0.514 of Primary=8.40 cfs 0.514 af ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 13 Link 11:Flow at Open Space Inflow=0.96 cfs 0.186 af Primary=0.96 cfs 0.186 af Link 14L:Stream Head Inflow=17.86 cfs 1.224 af Primary=17.86 cfs 1.224 af Total Runoff Area=13.797 ac Runoff Volume=1.923 af Average Runoff Depth=1.67" 56.03% Pervious=7.730 ac 43.97%Impervious=6.067 ac ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 14 Summary for Subcatchment 1: D.A. B (New Sheetflow) Runoff = 0.46 cfs @ 12.04 hrs, Volume= 0.027 af, Depth= 1.34" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description * 0.240 74 Sheet Flow Adjusted CN 0.240 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.6 Direct Entry, Summary for Subcatchment 2: D.A. A Runoff = 2.35 cfs @ 12.02 hrs, Volume= 0.127 af, Depth= 1.54" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description * 0.990 77 Adjusted CN 0.990 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Subcatchment 5: Onsite Not Detained (1) Runoff = 0.11 cfs @ 12.08 hrs, Volume= 0.008 af, Depth= 0.64" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description 0.150 61 >75%Grass cover, Good, HSG B 0.150 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (ft/sec) (cfs) 13.5 Direct Entry, ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 15 Summary for Subcatchment 6: Offsite Not Detained (1) Runoff = 0.73 cfs @ 11.99 hrs, Volume= 0.038 af, Depth= 2.88" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description • 0.140 98 Impervious 0.020 61 >75%Grass cover, Good, HSG B 0.160 93 Weighted Average 0.020 12.50% Pervious Area 0.140 87.50% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.5 Direct Entry, Summary for Subcatchment 8: On-Site Not Detained (2) Runoff = 0.37 cfs @ 11.99 hrs, Volume= 0.018 af, Depth= 1.28" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description 0.115 61 >75%Grass cover, Good, HSG B • 0.054 98 Impervious 0.169 73 Weighted Average 0.115 68.05% Pervious Area 0.054 31.95% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment 9: Off-Site Not Detained (2) Runoff = 1.19 cfs @ 11.97 hrs, Volume= 0.056 af, Depth= 2.07" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description 0.120 61 >75%Grass cover, Good, HSG B • 0.208 98 Impervious 0.328 84 Weighted Average 0.120 36.59%Pervious Area 0.208 63.41% Impervious Area ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 0 2020 HydroCAD Software Solutions LLC Page 16 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.1 Direct Entry, Summary for Subcatchment 12S: Original Sheetflow Area Runoff = 0.38 cfs @ 12.07 hrs, Volume= 0.032 af, Depth= 0.47" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description 0,246 61 >75%Grass cover, Good, HSG B 0.554 55 Woods, Good, HSG B 0.800 57 Weighted Average 0.800 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.6 Direct Entry, Summary for Subcatchment 13S: Watershed DA Runoff = 17.86 cfs @ 12.09 hrs, Volume= 1.224 af, Depth= 1.91" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description * 3.300 61 Turf * 4.400 98 Impervious 7.700 82 Weighted Average 3.300 42.86%Pervious Area 4.400 57.14% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.0 Direct Entry, Summary for Subcatchment 14S: Onsite Detained Runoff = 0.34 cfs @ 12.04 hrs, Volume= 0.020 af, Depth= 1.28" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type I124-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 17 Area(ac) CN Description * 0.060 98 Impervious 0.130 61 >75%Grass cover,Good, HSG B 0.190 73 Weighted Average 0.130 68.42%Pervious Area 0.060 31.58% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.0 Direct Entry, Summary for Subcatchment 15S: X2A Runoff = 2.81 cfs @ 12.06 hrs, Volume= 0.174 af, Depth= 1.34" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description * 0.536 98 IMPERVIOUS * 1.014 61 Turf 1.550 74 Weighted Average 1.014 65.42%Pervious Area 0.536 34.58%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.3 Direct Entry, Summary for Subcatchment 16S: X2 Runoff = 0.89 cfs @ 11.96 hrs, Volume= 0.042 af, Depth= 2.68" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description * 0.154 98 IMPERVIOUS * 0.036 61 Turf 0.190 91 Weighted Average 0.036 18.95%Pervious Area 0.154 81.05%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 18 Summary for Subcatchment 17S: X3 Runoff = 2.78 cfs @ 12.03 hrs, Volume= 0.156 af, Depth= 1.41" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description * 0.515 98 IMPERVIOUS * 0.815 61 Turf 1.330 75 Weighted Average 0.815 61.28%Pervious Area 0.515 38.72% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.9 Direct Entry, Summary for Pond 3: Vault Inflow Area= 0.990 ac, 0.00%Impervious, Inflow Depth= 1.54" for 2yr event Inflow = 2.35 cfs @ 12.02 hrs, Volume= 0.127 af Outflow = 2.35 cfs @ 12.02 hrs, Volume= 0.127 af, Atten=0%, Lag=0.2 min Primary = 2.35 cfs @ 12.02 hrs, Volume= 0.127 of Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span=0.00-48.00 hrs,dt=0.01 hrs Peak Elev=497.31'@ 12.02 hrs Surf.Area= 16 sf Storage= 17 cf Plug-Flow detention time=0.2 min calculated for 0.127 af(100%of inflow) Center-of-Mass det.time=0.2 min(845.8-845.6) Volume Invert Avail.Storage Storage Description #1 496.23' 98 cf 4.00'W x 4.00'L x 6.12'H 4'x4'Vault Storage Device Routing Invert Outlet Devices #1 Primary 496.17' 15.0" Round STM 5-6 L= 182.9' Ke=0.100 Inlet/Outlet Invert=496.17'/494.80' S=0.0075'/' Cc=0.900 n=0.011, Flow Area= 1.23 sf #2 Device 1 496.23' 24.0"W x 3.0" H Vert.Weir Plate Orifice C=0.600 Limited to weir flow at low heads #3 Secondary 497.33' 15.0" Round STM 3-4 L=69.1' Ke=0.100 Inlet/Outlet Invert=497.33'/490.18' S=0.1035'I' Cc=0.900 n=0.011, Flow Area= 1.23 sf #4 Device 3 496.24' 15.0" Round STM 4-5 L= 15.7' Ke=0.100 Inlet/Outlet Invert=496.19'/496.24' S=-0.0032'/' Cc=0.900 n=0.011, Flow Area= 1.23 sf ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 19 Primary OutFlow Max=2.35 cfs@ 12.02 hrs HW=497.31' (Free Discharge) L1=STM 5-6 (Passes 2.35 cfs of 4.87 cfs potential flow) L2=Weir Plate Orifice (Orifice Controls 2.35 cfs @ 4.69 fps) Secondary OutFlow Max=0.00 cfs@ 0.00 hrs HW=496.23' (Free Discharge) L3=STM 3-4 (Controls 0.00 cfs) L4=STM 4-5 (Controls 0.00 cfs) Summary for Pond 4: Detention Inflow Area= 0.990 ac, 0.00%Impervious, Inflow Depth= 1.54" for 2yr event Inflow = 2.35 cfs @ 12.02 hrs, Volume= 0.127 of Outflow = 0.14 cfs @ 13.24 hrs, Volume= 0.127 af, Atten=94°// Lag=72.9 min Primary = 0.14 cfs @ 13.24 hrs, Volume= 0.127 af Routing by Stor-Ind method, Time Span=0.00-48,00 hrs,dt=0.01 hrs Peak Elev=492.42'@ 13.24 hrs Surf.Area= 1,714 sf Storage=2,673 cf Plug-Flow detention time=210.3 min calculated for 0,127 af(100%of inflow) Center-of-Mass det,time=210.3 min ( 1,056.1 -845.8) Volume Invert Avail.Storage Storage Description #1 489.70' 2,936 cf Gravel(Prismatic)Listed below(Recalc) 9,256 cf Overall- 1,917 cf Embedded=7,339 cf x 40.0%Voids #2 489.70' 1,917 cf StormTech MC-4500 x 18 Inside#1 Effective Size=90.4"W x 60.0"H =>26.46 sf x 4.03'L= 106.5 cf Overall Size= 100.0"W x 60.0"H x 4.33'L with 0.31' Overlap 4,852 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 489.70 1,714 0 0 495.10 1,714 9,256 9,256 Device Routing Invert Outlet Devices #1 Primary 494.25' 32.0'long x 3.7'breadth Emergency Spillway Head(feet) 0.20 0.40 0,60 0,80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5,50 Coef.(English) 2.40 2.55 2.69 2.68 2.66 2.66 2.65 2.67 2.67 2.69 2.75 2.79 2.82 2.87 3.01 3.14 3.32 #2 Primary 489.70' 3.0" Round Culvert L= 110.0' Ke=0.800 Inlet/Outlet Invert=489.70'/488.00' S=0.0155'/' Cc=0.900 n=0.015, Flow Area=0.05 sf Primary OutFlow Max=0.14 cfs@ 13.24 hrs HW=492.42' (Free Discharge) I1=Emergency Spillway (Controls 0.00 cfs) 2=Culvert (Barrel Controls 0.14 cfs @ 2.94 fps) ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type I124-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 20 Summary for Pond 7: Detention Inflow Area= 0.190 ac, 31.58%Impervious, Inflow Depth= 1.28" for 2yr event Inflow = 0.34 cfs @ 12.04 hrs, Volume= 0.020 af Outflow = 0.34 cfs @ 12.04 hrs, Volume= 0.020 af, Atten=0%, Lag=0.0 min Primary = 0.34 cfs @ 12.04 hrs, Volume= 0.020 af Routing by Stor-Ind method, Time Span=0.00-48.00 hrs,dt=0.01 hrs Peak Elev=490.07'@ 12.04 hrs Surf.Area= 1 sf Storage=0 cf Plug-Flow detention time=0.0 min calculated for 0.020 af(100%of inflow) Center-of-Mass det.time=0,0 min(859.3-859.3) Volume Invert Avail.Storage Storage Description #1 490.03' 29 cf 15.0" Round 15"Storage L=23.4' S=0.0098'/' #2 490.26' 1,433 cf 48.0" Round 48"Storage x 3 L=38.0' S=0.0025'/' 1,461 cf Total Available Storage Device Routing Invert Outlet Devices #1 Primary 489.33' 15.0" Round Pipe 2-1 L= 123.9' Ke=0.600 Inlet/Outlet Invert=489.33'/482.35' S=0.0563'/' Cc=0.900 n=0.011, Flow Area= 1 23 sf #2 Device 1 489.53' 5.0"Vert. 1-yr Orifice C=0.600 Limited to weir flow at low heads #3 Device 1 491.93' 48.0"W x 5.0" H Vert. 10-yr Orifice C=0.600 Limited to weir flow at low heads Primary OutFlow Max=0.38 cfs@ 12.04 hrs HW=490.07' (Free Discharge) L1=Pipe 2-1 (Passes 0.38 cfs of 2.07 cfs potential flow) 12=1-yr Orifice (Orifice Controls 0.38 cfs @ 2.77 fps) 3=10-yr Orifice (Controls 0.00 cfs) Summary for Link 10: POA Inflow Area= 4.067 ac, 40.99%Impervious, Inflow Depth= 1.52" for 2yr event Inflow = 8.40 cfs @ 12.01 hrs, Volume= 0.514 of Primary = 8.40 cfs @ 12.01 hrs, Volume= 0.514 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-48.00 hrs, dt=0.01 hrs Summary for Link 11: Flow at Open Space Inflow Area= 2.030 ac, 0.00%Impervious, Inflow Depth= 1.10" for 2yr event Inflow = 0.96 cfs @ 12.06 hrs, Volume= 0.186 of Primary = 0.96 cfs @ 12.06 hrs, Volume= 0.186 at Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-48.00 hrs, dt=0.01 hrs ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 11 24-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 21 Summary for Link 14L: Stream Head Inflow Area= 7.700 ac, 57.14%Impervious, Inflow Depth= 1.91" for 2yr event Inflow = 17.86 cfs @ 12.09 hrs, Volume= 1.224 af Primary = 17.86 cfs @ 12.09 hrs, Volume= 1.224 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-48.00 hrs,dt=0.01 hrs ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 10yrRainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 22 Time span=0.00-48.00 hrs,dt=0.01 hrs,4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1: D.A.B(New Sheetflow) Runoff Area=0.240 ac 0.00% Impervious Runoff Depth=2.78" Tc=11.6 min CN=74 Runoff=0.97 cfs 0.056 af Subcatchment2: D.A.A Runoff Area=0.990 ac 0.00% Impervious Runoff Depth=3.06" Tc=10.0 min CN=77 Runoff=4.65 cfs 0.252 of Subcatchment 5:Onsite Not Detained(1) Runoff Area=0.150 ac 0.00%Impervious Runoff Depth=1.69" Tc=13.5 min CN=61 Runoff=0.33 cfs 0.021 af Subcatchment 6:Offsite Not Detained(1) Runoff Area=0.160 ac 87.50%Impervious Runoff Depth=4.70" Tc=7.5 min CN=93 Runoff=1.15 cfs 0.063 af Subcatchment 8:On-Site Not Detained(2) Runoff Area=0.169 ac 31.95% Impervious Runoff Depth=2.69" Tc=7.0 min CN=73 Runoff=0.78 cfs 0.038 of Subcatchment 9:Off-Site Not Detained(2) Runoff Area=0.328 ac 63.41%Impervious Runoff Depth=3.74" Tc=6.1 min CN=84 Runoff=2.11 cfs 0.102 af Subcatchment 12S:Original Sheetflow Area Runoff Area=0.800 ac 0.00%Impervious Runoff Depth=1.39" Tc=11.6 min CN=57 Runoff=1.50 cfs 0.092 of Subcatchment 13S:Watershed DA Runoff Area=7.700 ac 57.14%Impervious Runoff Depth=3.54" Tc=17.0 min CN=82 Runoff=32.91 cfs 2.271 af Subcatchment 14S:Onsite Detained Runoff Area=0.190 ac 31.58% Impervious Runoff Depth=2.69" Tc=12.0 min CN=73 Runoff=0.73 cfs 0.043 af Subcatchment 15S:X2A Runoff Area=1.550 ac 34.58%Impervious Runoff Depth=2.78" Tc=13.3 min CN=74 Runoff=5.91 cfs 0.359 of Subcatchment 16S:X2 Runoff Area=0.190 ac 81.05% Impervious Runoff Depth=4.48" Tc=5.0 min CN=91 Runoff=1.44 cfs 0.071 af Subcatchment 17S:X3 Runoff Area=1.330 ac 38.72%Impervious Runoff Depth=2.87" Tc=10.9 min CN=75 Runoff=5.70 cfs 0.318 of Pond 3:Vault Peak Elev=497.86' Storage=26 cf Inflow=4.65 cfs 0.252 of Primary=2.96 cfs 0.233 af Secondary=1.69 cfs 0.019 af Outflow=4.65 cfs 0.252 of Pond 4:Detention Peak EIev=494.30' Storage=4,292 cf Inflow=2.96 cfs 0.233 of Outflow=0.95 cfs 0.233 of Pond 7:Detention Peak Elev=492.03' Storage=621 cf Inflow=2.41 cfs 0.061 af Outflow=1.43 cfs 0.061 af Link 10:POA Inflow=16.93 cfs 1.033 of Primary=16.93 cfs 1.033 af ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type II 24-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 23 Link 11:Flow at Open Space Inflow=2.61 cfs 0.381 af Prmary=2.61 cfs 0.381 af Link 14L:Stream Head Inflow=32.91 cfs 2.271 af Primary=32.91 cfs 2.271 af Total Runoff Area=13.797 ac Runoff Volume=3.685 af Average Runoff Depth=3.20" 56.03% Pervious=7.730 ac 43.97%Impervious=6.067 ac ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 24 Summary for Subcatchment 1: D.A. B (New Sheetflow) Runoff = 0.97 cfs @ 12.04 hrs, Volume= 0.056 af, Depth= 2.78" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description * 0.240 74 Sheet Flow Adjusted CN 0.240 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.6 Direct Entry, Summary for Subcatchment 2: D.A. A Runoff = 4.65 cfs @ 12.02 hrs, Volume= 0.252 af, Depth= 3.06" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description * 0.990 77 Adjusted CN 0.990 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Subcatchment 5: Onsite Not Detained (1) Runoff = 0.33 cfs @ 12.07 hrs, Volume= 0.021 af, Depth= 1.69" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description 0.150 61 >75%Grass cover,Good, HSG B 0.150 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.5 Direct Entry, ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 0 2020 HydroCAD Software Solutions LLC Page 25 Summary for Subcatchment 6: Offsite Not Detained (1) Runoff = 1.15 cfs @ 11.98 hrs, Volume= 0.063 af, Depth= 4.70" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description * 0.140 98 Impervious 0.020 61 >75%Grass cover,Good, HSG B 0.160 93 Weighted Average 0.020 12.50%Pervious Area 0.140 87.50%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.5 Direct Entry, Summary for Subcatchment 8: On-Site Not Detained (2) Runoff = 0.78 cfs @ 11.99 hrs, Volume= 0.038 af, Depth= 2.69" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description 0115 61 >75%Grass cover,Good, HSG B * 0.054 98 Impervious 0.169 73 Weighted Average 0.115 68.05%Pervious Area 0.054 31.95% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment 9: Off-Site Not Detained (2) Runoff = 2.11 cfs @ 11.97 hrs, Volume= 0.102 af, Depth= 3.74" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description 0.120 61 >75%Grass cover,Good, HSG B * 0.208 98 Impervious 0.328 84 Weighted Average 0.120 36.59%Pervious Area 0.208 63.41% Impervious Area ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 26 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.1 Direct Entry, Summary for Subcatchment 12S: Original Sheetflow Area Runoff = 1.50 cfs @ 12.05 hrs, Volume= 0.092 af, Depth= 1.39" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description 0.246 61 >75%Grass cover, Good, HSG B 0.554 55 Woods, Good, HSG B 0.800 57 Weighted Average 0.800 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.6 Direct Entry, Summary for Subcatchment 13S: Watershed DA Runoff = 32.91 cfs @ 12.09 hrs, Volume= 2.271 af, Depth= 3.54" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description * 3.300 61 Turf * 4.400 98 Impervious 7.700 82 Weighted Average 3.300 42.86%Pervious Area 4.400 57.14% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.0 Direct Entry, Summary for Subcatchment 14S: Onsite Detained Runoff = 0.73 cfs @ 12.04 hrs, Volume= 0.043 af, Depth= 2.69" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type II 24-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 27 Area(ac) CN Description * 0.060 98 Impervious 0.130 61 >75%Grass cover,Good, HSG B 0.190 73 Weighted Average 0.130 68.42%Pervious Area 0.060 31.58% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.0 Direct Entry, Summary for Subcatchment 15S: X2A Runoff = 5.91 cfs @ 12.05 hrs, Volume= 0.359 af, Depth= 2.78" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description * 0.536 98 IMPERVIOUS * 1.014 61 Turf 1.550 74 Weighted Average 1.014 65.42%Pervious Area 0.536 34.58% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.3 Direct Entry, Summary for Subcatchment 16S: X2 Runoff = 1.44 cfs @ 11.96 hrs, Volume= 0.071 af, Depth= 4.48" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description * 0.154 98 IMPERVIOUS * 0.036 61 Turf 0.190 91 Weighted Average 0.036 18.95%Pervious Area 0.154 81.05%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 10yrRainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 28 Summary for Subcatchment 17S: X3 Runoff = 5.70 cfs @ 12.03 hrs, Volume= 0.318 af, Depth= 2.87" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description * 0.515 98 IMPERVIOUS * 0.815 61 Turf 1.330 75 Weighted Average 0.815 61.28%Pervious Area 0.515 38.72% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.9 Direct Entry, Summary for Pond 3: Vault Inflow Area= 0.990 ac, 0.00%Impervious, Inflow Depth= 3.06" for 10yr event Inflow = 4.65 cfs @ 12.02 hrs, Volume= 0.252 af Outflow = 4.65 cfs @ 12.02 hrs, Volume= 0.252 af, Atten=0%, Lag=0.1 min Primary = 2.96 cfs @ 12.02 hrs, Volume= 0.233 af Secondary= 1.69 cfs @ 12.02 hrs, Volume= 0.019 of Routing by Stor-Ind method,Time Span=0.00-48.00 hrs,dt=0.01 hrs Peak Elev=497.86'@ 12.02 hrs Surf.Area= 16 sf Storage=26 cf Plug-Flow detention time=0.2 min calculated for 0.252 af(100%of inflow) Center-of-Mass det.time=0.2 min (826.1 -825.9) Volume Invert Avail.Storage Storage Description #1 496.23' 98 cf 4.00'W x 4.00'L x 6.12'H 4'x4'Vault Storage Device Routing Invert Outlet Devices #1 Primary 496.17' 15.0" Round STM 5-6 L= 182.9' Ke=0.100 Inlet/Outlet Invert=496.17'/494.80' S=0.0075'/' Cc=0.900 n=0.011, Flow Area= 1.23 sf #2 Device 1 496.23' 24.0"W x 3.0" H Vert.Weir Plate Orifice C=0.600 Limited to weir flow at low heads #3 Secondary 497.33' 15.0" Round STM 3-4 L=69.1' Ke=0.100 Inlet/Outlet Invert=497.33'/490.18' S=0.1035'/' Cc=0.900 n=0.011, Flow Area= 1.23 sf #4 Device 3 496.24' 15.0" Round STM 4-5 L= 15.7' Ke=0.100 Inlet/Outlet Invert=496.19'/496.24' S=-0.0032'/' Cc=0.900 n=0.011, Flow Area= 1.23 sf ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 10yrRainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD010.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 29 Primary OutFlow Max=2.95 cfs@ 12,02 hrs HW=497.86' (Free Discharge) L1=STM 5-6 (Passes 2.95 cfs of 6.50 cfs potential flow) L2=Weir Plate Orifice (Orifice Controls 2.95 cfs @ 5.91 fps) Secondary OutFlow Max=1.69 cfs@ 12.02 hrs HW=497.86' (Free Discharge) L3=STM 3-4 (Inlet Controls 1.69 cfs @ 3.39 fps) L4=STM 4-5 (Passes 1.69 cfs of 5.48 cfs potential flow) Summary for Pond 4: Detention Inflow Area= 0.990 ac, 0.00%Impervious, Inflow Depth= 2.83" for 10yr event Inflow = 2.96 cfs @ 12.02 hrs, Volume= 0.233 of Outflow = 0.95 cfs @ 12.27 hrs, Volume= 0.233 af, Atten=68°/4 Lag= 15.4 min Primary = 0.95 cfs @ 12.27 hrs, Volume= 0.233 af Routing by Stor-Ind method,Time Span=0.00-48.00 hrs,dt=0.01 hrs Peak Elev=494.30'@ 12.27 hrs Surf.Area= 1,714 sf Storage=4,292 cf Plug-Flow detention time=267.6 min calculated for 0.233 af(100%of inflow) Center-of-Mass det.time=267.8 min( 1,102.2-834.4) Volume Invert Avail.Storage Storage Description #1 489.70' 2,936 cf Gravel(Prismatic)Listed below(Recalc) 9,256 cf Overall- 1,917 cf Embedded=7,339 cf x 40.0%Voids #2 489.70' 1,917 cf StormTech MC-4500 x 18 Inside#1 Effective Size=90.4"W x 60.0"H =>26.46 sf x 4.03'L= 106.5 cf Overall Size= 100.0"W x 60.0"H x 4.33'L with 0.31'Overlap 4,852 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 489.70 1,714 0 0 495.10 1,714 9,256 9,256 Device Routing Invert Outlet Devices #1 Primary 494,25' 32.0' long x 3.7'breadth Emergency Spillway Head(feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef.(English) 2.40 2.55 2.69 2.68 2.66 2.66 2.65 2.67 2.67 2.69 2.75 2.79 2.82 2.87 3.01 3.14 3.32 #2 Primary 489.70' 3.0" Round Culvert L= 110.0' Ke=0.800 Inlet/Outlet Invert=489.70'/488.00' S=0.0155 7' Cc=0.900 n=0.015, Flow Area=0.05 sf Primary OutFlow Max=0.90 cfs@ 12.27 hrs HW=494.29' (Free Discharge) -1=Emergency Spillway (Weir Controls 0.73 cfs @ 0.51 fps) 2=Culvert (Barrel Controls 0.17 cfs @ 3.54 fps) ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 30 Summary for Pond 7: Detention Inflow Area= 0.190 ac, 31.58%Impervious, Inflow Depth= 3.86" for 10yr event Inflow = 2.41 cfs @ 12.02 hrs, Volume= 0.061 af Outflow = 1,43 cfs @ 12.09 hrs, Volume= 0.061 af, Atten=40%, Lag=4.0 min Primary = 1.43 cfs @ 12.09 hrs, Volume= 0.061 af Routing by Stor-Ind method, Time Span=0.00-48.00 hrs,dt=0.01 hrs Peak Elev=492.03'@ 12.09 hrs Surf.Area=452 sf Storage=621 cf Plug-Flow detention time=(not calculated:outflow precedes inflow) Center-of-Mass det.time=3.5 min(805.6-802.1 ) Volume Invert Avail.Storage Storage Description #1 490.03' 29 cf 15.0" Round 15"Storage L= 23.4' S=0.0098'I' #2 490.26' 1,433 cf 48.0" Round 48"Storage x 3 L=38.0' S=0.0025'/' 1,461 cf Total Available Storage Device Routing Invert Outlet Devices #1 Primary 489.33' 15.0" Round Pipe 2-1 L= 123.9' Ke=0.600 Inlet/Outlet Invert=489.33'/482.35' S=0 0563'I' Cc=0.900 n=0.011, Flow Area= 1.23 sf #2 Device 1 489,53' 5.0"Vert. 1-yr Orifice C=0.600 Limited to weir flow at low heads #3 Device 1 491.93' 48.0"W x 5.0" H Vert. 10-yr Orifice C=0.600 Limited to weir flow at low heads Primary OutFlow Max=1.42 cfs@ 12.09 hrs HW=492.03' (Free Discharge) L1=Pipe 2-1 (Passes 1.42 cfs of 7.99 cfs potential flow) E2=1-yr Orifice (Orifice Controls 0.99 cfs @ 7.29 fps) 3=10-yr Orifice (Orifice Controls 0.42 cfs @ 1.03 fps) Summary for Link 10: POA Inflow Area= 4.067 ac, 40.99%Impervious, Inflow Depth= 3.05" for 10yr event Inflow = 16.93 cfs @ 12.01 hrs, Volume= 1.033 of Primary = 16.93 cfs @ 12.01 hrs, Volume= 1.033 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-48.00 hrs, dt=0.01 hrs Summary for Link 11: Flow at Open Space Inflow Area= 2.030 ac, 0.00%Impervious, Inflow Depth= 2.26" for 10yr event Inflow = 2.61 cfs @ 12.05 hrs, Volume= 0.381 af Primary = 2.61 cfs @ 12.05 hrs, Volume= 0.381 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-48.00 hrs, dt=0.01 hrs ASBUILT HILLBROOK ASBUILT POSTDEV HYDROCAD Type 1124-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 0 2020 HydroCAD Software Solutions LLC Page 31 Summary for Link 14L: Stream Head Inflow Area= 7.700 ac, 57.14%Impervious, Inflow Depth= 3.54" for 10yr event Inflow = 32.91 cfs@ 12.09 hrs, Volume= 2.271 af Primary = 32.91 cfs @ 12.09 hrs, Volume= 2.271 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-48.00 hrs, dt=0.01 hrs Hilibrook As-Built Amended HydroCAD Report Revised: 3-5-2020 ® 0 x2A 0 //// x2 \ 9\\/ X3 1 Off-Site \\Not Detained O (2) D A.B(Ne Sheetflow) K \ O final Shee rlow Area 8 \ P 10 DIA A — — On-Site Not Detained 14t (2) 1 �� � Strea ead d - -A—D A Flow at Open Space - Dete ion Vault Detention I Onsite Not Detained(1) (14S) Watershed DA OHsite Not Detained(1) Onsite Detained 4ua) Reach Pon Link Drainage Diagram for HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Prepared by(enter your company name here}, Printed 1/30/2020 �----' HydroCAD®9.10 s/n 07054 ©2011 HydroCAD Software Solutions LLC AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type II 24-hr lyrRainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 2 Time span=0.00-48.00 hrs, dt=0.01 hrs,4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1:D.A.B(New Sheetflow) Runoff Area=0.240 ac 0.00%Impervious Runoff Depth=0.91" Tc=11.6 min CN=74 Runoff=0.31 cfs 0.018 af Subcatchment2: D.A.A Runoff Area=0.990 ac 0.00%Impervious Runoff Depth=1.08" Tc=10.0 min CN=77 Runoff=1.63 cfs 0.089 of Subcatchment5:Onsite Not Detained(1) Runoff Area=0.150 ac 0.00% Impervious Runoff Depth=0.37" Tc=13.5 min CN=61 Runoff=0.05 cfs 0.005 af Subcatchment 6:Offsite Not Detained(1) Runoff Area=0.160 ac 87.50%Impervious Runoff Depth=2.26" Tc=7.5 min CN=93 Runoff=0.58 cfs 0.030 af Subcatchment8:On-Site Not Detained(2) Runoff Area=0.169 ac 31.95%Impervious Runoff Depth=0.86" Tc=7.0 min CN=73 Runoff=0.25 cfs 0.012 af Subcatchment9:Off-Site Not Detained(2) Runoff Area=0.328 ac 63.41%Impervious Runoff Depth=1.52" Tc=6.1 min CN=84 Runoff=0.89 cfs 0.042 af Subcatchment12S:Original Sheetflow Area Runoff Area=0.800 ac 0.00% Impervious Runoff Depth=0.25" Tc=11.6 min CN=57 Runoff=0.13 cfs 0.017 af Subcatchment 13S:Watershed DA Runoff Area=7.700 ac 57.14% Impervious Runoff Depth=1.39" Tc=17.0 min CN=82 Runoff=12.92 cfs 0.890 af Subcatchment 14S:Onsite Detained Runoff Area=0.190 ac 31.58% Impervious Runoff Depth=0.86" Tc=12.0 min CN=73 Runoff=0.22 cfs 0.014 af Subcatchment 15S:X2A Runoff Area=1.550 ac 34.58% Impervious Runoff Depth=0.91" Tc=13.3 min CN=74 Runoff=1.86 cfs 0.118 af Subcatchment 16S:X2 Runoff Area=0.190 ac 81.05% Impervious Runoff Depth=2.08" Tc=5.0 min CN=91 Runoff=0.70 cfs 0.033 of Subcatchment 17S:X3 Runoff Area=1.330 ac 38.72%Impervious Runoff Depth=0.97" Tc=10.9 min CN=75 Runoff=1.87 cfs 0.107 af Pond 3:Vault Peak Elev=496.81' Storage=9 cf Inflow=1.63 cfs 0.089 af Primary=1.63 cfs 0.089 af Secondary=0.00 cfs 0.000 of Outflow=1.63 cfs 0.089 af Pond 4:Detention Peak Elev=491.39' Storage=1,692 cf Inflow=1.63 cfs 0.089 af Outflow=013 cfs 0.089 af Pond 7:Detention Peak EIev=490.66' Storage=73 cf Inflow=0.22 cfs 0.014 af Outflow=0.11 cfs 0.014 of Link 10:POA Inflow=5.67 cfs 0.361 af Primary=5.67 cfs 0.361 of AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr lyrRainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 0 2020 HydroCAD Software Solutions LLC Page 3 Link 11:Flow at Open Space Inflow=0.53 cfs 0.124 af Primary=0.53 cfs 0.124 af Link 14L:Stream Head Inflow=12.92 cfs 0.890 af Primary=12.92 cfs 0.890 af Total Runoff Area=13.797 ac Runoff Volume=1.374 af Average Runoff Depth=1.20" 56.03% Pervious=7.730 ac 43.97%Impervious=6.067 ac AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type I124-hr lyrRainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment 1: D.A. B (New Sheetflow) Runoff = 0.31 cfs @ 12.05 hrs, Volume= 0.018 af, Depth= 0.91" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description * 0.240 74 Sheet Flow Adjusted CN 0.240 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.6 Direct Entry, Summary for Subcatchment 2: D.A.A Runoff = 1.63 cfs @ 12.02 hrs, Volume= 0.089 af, Depth= 1.08" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 1 yr Rainfall=3.01" Area(ac) CN Description * 0.990 77 Adjusted CN 0.990 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Subcatchment 5: Onsite Not Detained (1) Runoff = 0.05 cfs @ 12.10 hrs, Volume= 0.005 af, Depth= 0.37" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 1 yr Rainfall=3.01" Area(ac) CN Description 0.150 61 >75%Grass cover, Good, HSG B 0.150 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.5 Direct Entry, AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 1 yr Rainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment 6: Offsite Not Detained (1) Runoff = 0.58 cfs @ 11.99 hrs, Volume= 0.030 af, Depth= 2.26" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description * 0.140 98 Impervious 0.020 61 >75%Grass cover, Good, HSG B 0.160 93 Weighted Average 0.020 12.50%Pervious Area 0.140 87.50% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.5 Direct Entry, Summary for Subcatchment 8: On-Site Not Detained (2) Runoff = 0.25 cfs @ 11.99 hrs, Volume= 0.012 af, Depth= 0.86" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0,00-48.00 hrs, dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description 0.115 61 >75%Grass cover, Good, HSG B * 0.054 98 Impervious 0.169 73 Weighted Average 0.115 68.05% Pervious Area 0.054 31.95% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment 9: Off-Site Not Detained (2) Runoff = 0.89 cfs @ 11.98 hrs, Volume= 0.042 af, Depth= 1.52" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description 0.120 61 >75%Grass cover,Good, HSG B * 0.208 98 Impervious 0.328 84 Weighted Average 0.120 36.59% Pervious Area 0.208 63.41%Impervious Area AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type I124-hr 1 yr Rainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD010.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 6 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.1 Direct Entry, Summary for Subcatchment 12S: Original Sheetflow Area Runoff = 0.13 cfs @ 12,09 hrs, Volume= 0.017 af, Depth= 0.25" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description 0.246 61 >75%Grass cover, Good, HSG B 0,554 55 Woods, Good, HSG B 0.800 57 Weighted Average 0.800 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.6 Direct Entry, Summary for Subcatchment 13S: Watershed DA Runoff = 12.92 cfs @ 12.10 hrs, Volume= 0.890 af, Depth= 1.39" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description 3.300 61 Turf * 4.400 98 Impervious 7.700 82 Weighted Average 3.300 42.86%Pervious Area 4.400 57.14%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.0 Direct Entry, Summary for Subcatchment 14S: Onsite Detained Runoff = 0.22 cfs @ 12.05 hrs, Volume= 0.014 af, Depth= 0.86" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 1 yr Rainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 7 Area(ac) CN Description * 0.060 98 Impervious 0.130 61 >75%Grass cover,Good, HSG B 0.190 73 Weighted Average 0.130 68.42%Pervious Area 0.060 31.58% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.0 Direct Entry, Summary for Subcatchment 15S: X2A Runoff = 1.86 cfs @ 12.06 hrs, Volume= 0.118 af, Depth= 0.91" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48,00 hrs,dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description * 0.536 98 IMPERVIOUS * 1.014 61 Turf 1.550 74 Weighted Average 1.014 65.42% Pervious Area 0.536 34.58% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.3 Direct Entry, Summary for Subcatchment 16S: X2 Runoff = 0.70 cfs @ 11.96 hrs, Volume= 0.033 af, Depth= 2.08" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 1 yr Rainfall=3.01" Area(ac) CN Description * 0.154 98 IMPERVIOUS * 0.036 61 Turf 0.190 91 Weighted Average 0.036 18.95%Pervious Area 0.154 81.05%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 1 yr Rainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment 17S: X3 Runoff = 1.87 cfs @ 12.03 hrs, Volume= 0.107 af, Depth= 0.97" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN,Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 1yr Rainfall=3.01" Area(ac) CN Description * 0.515 98 IMPERVIOUS * 0.815 61 Turf 1.330 75 Weighted Average 0.815 61.28%Pervious Area 0.515 38.72% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.9 Direct Entry, Summary for Pond 3: Vault Inflow Area= 0.990 ac, 0.00%Impervious, Inflow Depth = 1.08" for 1 yr event Inflow = 1.63 cfs @ 12.02 hrs, Volume= 0.089 of Outflow = 1.63 cfs @ 12.03 hrs, Volume= 0.089 af, Atten=0%, Lag=0.1 min Primary = 1.63 cfs @ 12.03 hrs, Volume= 0.089 af Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span=0.00-48.00 hrs,dt=0.01 hrs Peak Elev=496.81'@ 12.03 hrs Surf.Area= 16 sf Storage=9 cf Plug-Flow detention time=0.2 min calculated for 0.089 af(100%of inflow) Center-of-Mass det.time=0.2 min(856.4-856.3) Volume Invert Avail.Storage Storage Description #1 496.23' 98 cf 4.00'W x 4.00'L x 6.12'H 4'x4'Vault Storage Device Routing Invert Outlet Devices #1 Primary 496.17' 15.0" Round STM 5-6 L= 182.9' Ke=0.100 Inlet/Outlet Invert=496.17'/494.80' S=0.0075'/' Cc=0.900 n=0.011, Flow Area= 1.23 sf #2 Device 1 496.23' 24.0"W x 3.0"H Vert.Weir Plate Orifice C=0.600 Limited to weir flow at low heads #3 Secondary 497.33' 15.0" Round STM 3-4 L=69.1' Ke=0.100 Inlet/Outlet Invert=497.33'/490.18' S=0.1035'/' Cc=0.900 n=0.011, Flow Area= 1.23 sf #4 Device 3 496.24' 15.0" Round STM 4-5 L= 15.7' Ke=0.100 Inlet/Outlet Invert=496.19'/496.24' S=-0.0032 7 Cc=0.900 n=0.011, Flow Area= 1.23 sf AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type II 24-hr lyrRainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 9 Primary OutFlow Max=1.62 cfs@ 12.03 hrs HW=496.81' (Free Discharge) L1=STM 5-6 (Passes 1.62 cfs of 1.94 cfs potential flow) L2=Weir Plate Orifice (Orifice Controls 1.62 cfs @ 3.25 fps) Secondary OutFlow Max=0.00 cfs@ 0.00 hrs HW=496.23' (Free Discharge) 1-3=STM 3-4 (Controls 0.00 cfs) L4=STM 4-5 (Controls 0.00 cfs) Summary for Pond 4: Detention Inflow Area= 0.990 ac, 0.00%Impervious, Inflow Depth= 1.08" for 1 yr event Inflow = 1.63 cfs @ 12.03 hrs, Volume= 0.089 of Outflow = 0.13 cfs @ 12.97 hrs, Volume= 0.089 af, Atten=92%, Lag=56.9 min Primary = 0.13 cfs @ 12.97 hrs, Volume= 0.089 of Routing by Stor-Ind method,Time Span=0.00-48.00 hrs,dt=0.01 hrs Peak Elev=491.39'@ 12.97 hrs Surf.Area= 1,714 sf Storage= 1,692 cf Plug-Flow detention time=149.8 min calculated for 0.089 af(100%of inflow) Center-of-Mass det.time=149.8 min( 1,006.2-856.4) Volume Invert Avail.Storage Storage Description #1 489.70' 2,936 cf Gravel(Prismatic)Listed below(Recalc) 9,256 cf Overall- 1,917 cf Embedded=7,339 cf x 40.0%Voids #2 489.70' 1,917 cf StormTech MC-4500 x 18 Inside#1 Effective Size=90.4"W x 60.0"H =>26.46 sf x 4.03'L= 106.5 cf Overall Size= 100.0"W x 60.0"H x 4.33'L with 0.31' Overlap 4,852 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 489.70 1,714 0 0 495.10 1,714 9,256 9,256 Device Routing Invert Outlet Devices #1 Primary 494.25' 32.0' long x 3.7'breadth Emergency Spillway Head(feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef.(English) 2.40 2.55 2.69 2.68 2.66 2.66 2.65 2.67 2.67 2.69 2.75 2.79 2.82 2.87 3.01 3.14 3.32 #2 Primary 489.70' 3.0" Round Culvert L= 110.0' Ke=0.800 Inlet/Outlet Invert=489.70'/488.00' S=0.01557 Cc=0.900 n=0.015, Flow Area=0.05 sf Primary OutFlow Max=0.13 cfs@ 12.97 hrs HW=491.39' (Free Discharge) E1=Emergency Spillway (Controls 0.00 cfs) 2=Culvert (Barrel Controls 0.13 cfs @ 2.56 fps) AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 1 yr Rainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 0 2020 HydroCAD Software Solutions LLC Page 10 Summary for Pond 7: Detention Inflow Area= 0.190 ac, 31.58%Impervious, Inflow Depth= 0.86" for 1 yr event Inflow = 0.22 cfs @ 12.05 hrs, Volume= 0.014 of Outflow = 0.11 cfs @ 12.19 hrs, Volume= 0.014 af, Atten=52°/g Lag=8.5 min Primary = 0.11 cfs @ 12.19 hrs, Volume= 0.014 of Routing by Stor-Ind method,Time Span=0.00-48.00 hrs,dt=0.01 hrs Peak Elev=490.66'@ 12.19 hrs Surf.Area= 286 sf Storage=73 cf Plug-Flow detention time=(not calculated:outflow precedes inflow) Center-of-Mass det.time=2.8 min(874.7-871.8) Volume Invert Avail.Storage Storage Description #1 490.03' 29 cf 15.0" Round 15"Storage L=23.4' S=0.0098'I' #2 490.26' 1,433 cf 48.0" Round 48" Storage x 3 L=38.0' S=0.0025'/' 1,461 cf Total Available Storage Device Routing Invert Outlet Devices #1 Primary 489.33' 15.0" Round Pipe 2-1 L= 123.9' Ke=0.600 Inlet/Outlet Invert=489.33'/482.35' S=0.0563'/' Cc=0.900 n=0.011, Flow Area= 1.23 sf #2 Device 1 489.53' 2.0"Vert. 1-yr Orifice C=0.600 Limited to weir flow at low heads #3 Device 1 491.93' 48.0"W x 5.0" H Vert. 10-yr Orifice C=0.600 Limited to weir flow at low heads Primary OutFlow Max=0.11 cfs@ 12.19 hrs HW=490.66' (Free Discharge) t-1=Pipe 2-1 (Passes 0.11 cfs of 4.65 cfs potential flow) L2=1-yr Orifice (Orifice Controls 0.11 cfs @ 4.92 fps) 3=10-yr Orifice (Controls 0.00 cfs) Summary for Link 10: POA Inflow Area= 4.067 ac, 40.99%Impervious, Inflow Depth = 1.06" for 1 yr event Inflow = 5.67 cfs @ 12.01 hrs, Volume= 0.361 af Primary = 5.67 cfs @ 12.01 hrs, Volume= 0.361 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-48.00 hrs, dt=0.01 hrs Summary for Link 11: Flow at Open Space Inflow Area= 2.030 ac, 0.00%Impervious, Inflow Depth= 0.73" for 1 yr event Inflow = 0.53 cfs @ 12.06 hrs, Volume= 0.124 af Primary = 0.53 cfs @ 12.06 hrs, Volume= 0.124 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-48.00 hrs,dt=0.01 hrs AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type II 24-hr 1 yr Rainfall=3.01" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 11 Summary for Link 14L: Stream Head Inflow Area= 7.700 ac, 57.14%Impervious, Inflow Depth= 1.39" for 1 yr event Inflow = 12.92 cfs @ 12.10 hrs, Volume= 0.890 of Primary = 12.92 cfs @ 12.10 hrs, Volume= 0.890 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-48.00 hrs, dt=0.01 hrs AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type II 24-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 12 Time span=0.00-48.00 hrs,dt=0.01 hrs,4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1: D.A.B(New Sheetflow) Runoff Area=0.240 ac 0.00%Impervious Runoff Depth=1.34" Tc=11.6 min CN=74 Runoff=0.46 cfs 0.027 af Subcatchment 2: D.A.A Runoff Area=0.990 ac 0.00%Impervious Runoff Depth=1.54" Tc=10.0 min CN=77 Runoff=2.35 cfs 0.127 of Subcatchment5:Onsite Not Detained(1) Runoff Area=0.150 ac 0.00% Impervious Runoff Depth=0.64" Tc=13.5 min CN=61 Runoff=0.11 cfs 0.008 af Subcatchment6:Offsite Not Detained(1) Runoff Area=0.160 ac 87.50%Impervious Runoff Depth=2.88" Tc=7.5 min CN=93 Runoff=0.73 cfs 0.038 af Subcatchment 8:On-Site Not Detained(2) Runoff Area=0.169 ac 31.95% Impervious Runoff Depth=1.28" Tc=7.0 min CN=73 Runoff=0.37 cfs 0.018 af Subcatchment 9:Off-Site Not Detained(2) Runoff Area=0.328 ac 63.41%Impervious Runoff Depth=2 07" Tc=6.1 min CN=84 Runoff=1.19 cfs 0.056 of Subcatchment 12S:Original Sheetflow Area Runoff Area=0.800 ac 0.00% Impervious Runoff Depth=0.47" Tc=11.6 min CN=57 Runoff=0.38 cfs 0.032 of Subcatchment 13S:Watershed DA Runoff Area=7.700 ac 57.14% Impervious Runoff Depth=1.91" Tc=17.0 min CN=82 Runoff=17.86 cfs 1.224 of Subcatchment14S:Onsite Detained Runoff Area=0.190 ac 31.58% Impervious Runoff Depth=1.28" Tc=12.0 min CN=73 Runoff=0.34 cfs 0.020 af Subcatchment 15S:X2A Runoff Area=1.550 ac 34.58%Impervious Runoff Depth=1.34" Tc=13.3 min CN=74 Runoff=2.81 cfs 0.174 of Subcatchment 16S:X2 Runoff Area=0.190 ac 81.05%Impervious Runoff Depth=2.68" Tc=5.0 min CN=91 Runoff=0.89 cfs 0.042 of Subcatchment 17S:X3 Runoff Area=1.330 ac 38.72% Impervious Runoff Depth=1.41" Tc=10.9 min CN=75 Runoff=2.78 cfs 0.156 af Pond 3:Vault Peak Elev=497.31' Storage=17 cf Inflow=2.35 cfs 0.127 af Primary=2.35 cfs 0.127 af Secondary=0.00 cfs 0.000 af Outflow=2.35 cfs 0.127 af Pond 4:Detention Peak Elev=492.42' Storage=2,673 cf Inflow=2 35 cfs 0 127 af Outflow=0.14 cfs 0.127 of Pond 7:Detention Peak EIev=490.94' Storage=166 cf Inflow=0.34 cfs 0.020 af Outflow=0.12 cfs 0.020 of Link 10:POA Inflow=8.18 cfs 0.514 af Primary=8.18 cfs 0.514 of AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1I 24-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 13 Link 11:Flow at Open Space Inflow=0.96 cfs 0.186 af Primary=0.96 cfs 0.186 af Link 14L:Stream Head Inflow=17.86 cfs 1.224 af Primary=17.86 cfs 1.224 af Total Runoff Area=13.797 ac Runoff Volume=1.923 af Average Runoff Depth= 1.67" 56.03% Pervious=7.730 ac 43.97%Impervious=6.067 ac AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 14 Summary for Subcatchment 1: D.A. B (New Sheetflow) Runoff = 0.46 cfs @ 12.04 hrs, Volume= 0.027 af, Depth= 1.34" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description * 0.240 74 Sheet Flow Adjusted CN 0.240 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.6 Direct Entry, Summary for Subcatchment 2: D.A. A Runoff = 2.35 cfs @ 12.02 hrs, Volume= 0.127 af, Depth= 1.54" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description * 0.990 77 Adjusted CN 0.990 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Subcatchment 5: Onsite Not Detained (1) Runoff = 0.11 cfs @ 12.08 hrs, Volume= 0.008 af, Depth= 0.64" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description 0.150 61 >75%Grass cover, Good, HSG B 0.150 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.5 Direct Entry, AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 0 2020 HydroCAD Software Solutions LLC Page 15 Summary for Subcatchment 6: Offsite Not Detained (1) Runoff = 0.73 cfs @ 11.99 hrs, Volume= 0.038 af, Depth= 2.88" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48,00 hrs, dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description * 0.140 98 Impervious 0.020 61 >75%Grass cover,Good, HSG B 0.160 93 Weighted Average 0.020 12.50% Pervious Area 0.140 87.50% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.5 Direct Entry, Summary for Subcatchment 8: On-Site Not Detained (2) Runoff = 0.37 cfs @ 11.99 hrs, Volume= 0.018 af, Depth= 1.28" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description 0.115 61 >75%Grass cover,Good, HSG B * 0.054 98 Impervious 0.169 73 Weighted Average 0.115 68.05%Pervious Area 0.054 31.95%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment 9: Off-Site Not Detained (2) Runoff = 1.19 cfs @ 11.97 hrs, Volume= 0.056 af, Depth= 2.07" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description 0.120 61 >75%Grass cover,Good, HSG B * 0.208 98 Impervious 0,328 84 Weighted Average 0.120 36.59%Pervious Area 0.208 63.41% Impervious Area AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 16 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.1 Direct Entry, Summary for Subcatchment 12S: Original Sheetflow Area Runoff = 0.38 cfs @ 12.07 hrs, Volume= 0.032 af, Depth= 0.47" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description 0.246 61 >75%Grass cover,Good, HSG B 0.554 55 Woods, Good, HSG B 0.800 57 Weighted Average 0.800 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.6 Direct Entry, Summary for Subcatchment 13S: Watershed DA Runoff = 17.86 cfs @ 12.09 hrs, Volume= 1.224 af, Depth= 1.91" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description 3.300 61 Turf 4.400 98 Impervious 7.700 82 Weighted Average 3.300 42.86%Pervious Area 4.400 57.14%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.0 Direct Entry, Summary for Subcatchment 14S: Onsite Detained Runoff = 0.34 cfs @ 12.04 hrs, Volume= 0.020 af, Depth= 1.28" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 17 Area(ac) CN Description * 0.060 98 Impervious 0.130 61 >75%Grass cover,Good, HSG B 0.190 73 Weighted Average 0.130 68.42% Pervious Area 0.060 31.58% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.0 Direct Entry, Summary for Subcatchment 15S: X2A Runoff = 2.81 cfs @ 12.06 hrs, Volume= 0.174 af, Depth= 1.34" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description * 0.536 98 IMPERVIOUS * 1.014 61 Turf 1.550 74 Weighted Average 1.014 65.42%Pervious Area 0.536 34.58%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.3 Direct Entry, Summary for Subcatchment 16S: X2 Runoff = 0.89 cfs @ 11.96 hrs, Volume= 0.042 af, Depth= 2.68" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description * 0.154 98 IMPERVIOUS * 0.036 61 Turf 0.190 91 Weighted Average 0.036 18.95%Pervious Area 0.154 81.05% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type II 24-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 18 Summary for Subcatchment 17S: X3 Runoff = 2.78 cfs @ 12.03 hrs, Volume= 0.156 af, Depth= 1.41" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 2yr Rainfall=3.65" Area(ac) CN Description * 0.515 98 IMPERVIOUS * 0.815 61 Turf 1.330 75 Weighted Average 0.815 61.28%Pervious Area 0.515 38.72%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.9 Direct Entry, Summary for Pond 3: Vault Inflow Area= 0.990 ac, 0.00%Impervious, Inflow Depth= 1.54" for 2yr event Inflow = 2.35 cfs @ 12.02 hrs, Volume= 0.127 of Outflow = 2,35 cfs @ 12.02 hrs, Volume= 0.127 af, Atten=0%, Lag=0.2 min Primary = 2.35 cfs @ 12.02 hrs, Volume= 0.127 of Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method,Time Span=0.00-48.00 hrs, dt=0.01 hrs Peak Elev=497.31'@ 12.02 hrs Surf.Area= 16 sf Storage= 17 cf Plug-Flow detention time=0.2 min calculated for 0.127 af(100%of inflow) Center-of-Mass det.time=0.2 min(845.8-845.6) Volume Invert Avail.Storage Storage Description #1 496.23' 98 cf 4.00'W x 4.00'L x 6.12'H 4'x4'Vault Storage Device Routing Invert Outlet Devices #1 Primary 496.17' 15.0" Round STM 5-6 L= 182.9' Ke=0.100 Inlet/Outlet Invert=496.17'/494.80' S=0.0075 7' Cc=0.900 n=0.011, Flow Area= 1.23 sf #2 Device 1 496.23' 24.0"W x 3.0"H Vert.Weir Plate Orifice C=0.600 Limited to weir flow at low heads #3 Secondary 497.33' 15.0" Round STM 3-4 L=69.1' Ke=0.100 Inlet/Outlet Invert=497.33'/490.18' S=0.1035 7' Cc=0.900 n=0.011, Flow Area= 1.23 sf #4 Device 3 496.24' 15.0" Round STM 4-5 L= 15.7' Ke=0.100 Inlet/Outlet Invert=496.19'/496.24' S=-0.0032't Cc=0.900 n=0.011, Flow Area= 1.23 sf AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD©10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 19 Primary OutFlow Max=2.35 cfs@ 12.02 hrs HW=497.31' (Free Discharge) L1=STM 5-6 (Passes 2,35 cfs of 4.87 cfs potential flow) L2=Weir Plate Orifice (Orifice Controls 2.35 cfs @ 4.69 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=496.23' (Free Discharge) L3=STM 3.4 (Controls 0.00 cfs) t4=STM 4-5 (Controls 0.00 cfs) Summary for Pond 4: Detention Inflow Area= 0.990 ac, 0.00%Impervious, Inflow Depth= 1.54" for 2yr event Inflow = 2.35 cfs @ 12.02 hrs, Volume= 0,127 of Outflow = 0.14 cfs @ 13.24 hrs, Volume= 0.127 af, Atten=94°/4 Lag=72.9 min Primary = 0.14 cfs @ 13.24 hrs, Volume= 0.127 af Routing by Stor-Ind method, Time Span=0.00-48.00 hrs,dt=0.01 hrs Peak Elev=492.42'@ 13.24 hrs Surf.Area= 1,714 sf Storage=2,673 cf Plug-Flow detention time=210.3 min calculated for 0.127 of(100%of inflow) Center-of-Mass det.time=210.3 min( 1,056.1 -845.8) Volume Invert Avail.Storage Storage Description #1 489.70' 2,936 cf Gravel(Prismatic)Listed below(Recalc) 9,256 cf Overall-1,917 cf Embedded=7,339 cf x 40.0%Voids #2 489.70' 1,917 cf StormTech MC-4500 x 18 Inside#1 Effective Size=90.4"W x 60.0"H =>26.46 sf x 4.03'L= 106.5 cf Overall Size= 100.0"W x 60.0"H x 4.33'L with 0.31'Overlap 4,852 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 489.70 1,714 0 0 495.10 1,714 9,256 9,256 Device Routing Invert Outlet Devices #1 Primary 494.25' 32.0' long x 3.7'breadth Emergency Spillway Head(feet) 0.20 0.40 0,60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4,00 4.50 5.00 5.50 Coef.(English) 2.40 2.55 2.69 2.68 2.66 2.66 2.65 2.67 2.67 2.69 2.75 2.79 2.82 2.87 3.01 3.14 3.32 #2 Primary 489.70' 3.0" Round Culvert L= 110.0' Ke=0.800 Inlet/Outlet Invert=489.70'/488.00' S=0.0155't Cc=0.900 n=0.015, Flow Area=0.05 sf Primary OutFlow Max=0.14 cfs@ 13.24 hrs HW=492.42' (Free Discharge) L1=Emergency Spillway (Controls 0.00 cfs) 2=Culvert (Barrel Controls 0.14 cfs @ 2.94 fps) AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD010.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 20 Summary for Pond 7: Detention Inflow Area= 0.190 ac, 31.58%Impervious, Inflow Depth= 1.28" for 2yr event Inflow = 0.34 cfs @ 12.04 hrs, Volume= 0.020 af Outflow = 0.12 cfs @ 12.23 hrs, Volume= 0.020 af, Atten=65%, Lag= 11.3 min Primary = 0.12 cfs @ 12.23 hrs, Volume= 0.020 af Routing by Stor-Ind method,Time Span=0.00-48.00 hrs,dt=0.01 hrs Peak Elev=490.94'@ 12.23 hrs Surf,Area=361 sf Storage= 166 cf Plug-Flow detention time=(not calculated:outflow precedes inflow) Center-of-Mass det.time=7.0 min(866.4-859.3) Volume Invert Avail.Storage Storage Description #1 490.03' 29 cf 15.0" Round 15"Storage L=23.4' S=0.0098'/' #2 490.26' 1,433 cf 48.0" Round 48"Storage x 3 L=38.0' S=0.0025'/' 1,461 cf Total Available Storage Device Routing Invert Outlet Devices #1 Primary 489.33' 15.0" Round Pipe 2-1 L= 123.9' Ke=0.600 Inlet/Outlet Invert=489 33'/482.35' S=0.0563'/' Cc=0.900 n=0.011, Flow Area= 1.23 sf #2 Device 1 489.53' 2.0"Vert. 1-yr Orifice C=0.600 Limited to weir flow at low heads #3 Device 1 491.93' 48.0"W x 5.0" H Vert. 10-yr Orifice C=0.600 Limited to weir flow at low heads Primary OutFlow Max=0.12 cfs@ 12.23 hrs HW=490.94' (Free Discharge) L1=Pipe 2-1 (Passes 0.12 cfs of 5.51 cfs potential flow) 12=1-yr Orifice (Orifice Controls 0.12 cfs @ 5.55 fps) 3=10-yr Orifice (Controls 0.00 cfs) Summary for Link 10: POA Inflow Area= 4.067 ac, 40.99%Impervious, Inflow Depth= 1.52" for 2yr event Inflow = 8.18 cfs @ 12.01 hrs, Volume= 0.514 of Primary = 8.18 cfs @ 12.01 hrs, Volume= 0.514 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-48.00 hrs,dt=0.01 hrs Summary for Link 11: Flow at Open Space Inflow Area= 2.030 ac, 0.00%Impervious, Inflow Depth= 1.10" for 2yr event Inflow = 0.96 cfs @ 12.06 hrs, Volume= 0.186 af Primary = 0.96 cfs @ 12.06 hrs, Volume= 0.186 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow, Time Span=0.00-48.00 hrs, dt=0.01 hrs AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type II 24-hr 2yr Rainfall=3.65" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 21 Summary for Link 14L: Stream Head Inflow Area= 7.700 ac, 57.14%Impervious, Inflow Depth= 1.91" for 2yr event Inflow = 17.86 cfs @ 12.09 hrs, Volume= 1.224 of Primary = 17.86 cfs @ 12.09 hrs, Volume= 1.224 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-48.00 hrs, dt=0,01 hrs AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 22 Time span=0.00-48.00 hrs, dt=0.01 hrs,4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1: D.A.B(New Sheetflow) Runoff Area=0 240 ac 0.00% Impervious Runoff Depth=2.78" Tc=11.6 min CN=74 Runoff=0.97 cfs 0.056 af Subcatchment2: D.A.A Runoff Area=0.990 ac 0.00% Impervious Runoff Depth=3.06" Tc=10.0 min CN=77 Runoff=4.65 cfs 0.252 of Subcatchment 5:Onsite Not Detained(1) Runoff Area=0.150 ac 0.00%Impervious Runoff Depth=1.69" Tc=13.5 min CN=61 Runoff=0.33 cfs 0.021 af Subcatchment6:Offsite Not Detained(1) Runoff Area=0.160 ac 87.50%Impervious Runoff Depth=4.70" Tc=7.5 min CN=93 Runoff=1.15 cfs 0.063 of Subcatchment 8:On-Site Not Detained(2) Runoff Area=0.169 ac 31.95%Impervious Runoff Depth=2.69" Tc=7.0 min CN=73 Runoff=0.78 cfs 0.038 af Subcatchment 9:Off-Site Not Detained(2) Runoff Area=0.328 ac 63.41% Impervious Runoff Depth=3.74" Tc=6.1 min CN=84 Runoff=2.11 cfs 0.102 of Subcatchment12S:Original Sheetflow Area Runoff Area=0.800 ac 0.00% Impervious Runoff Depth=1.39" Tc=11.6 min CN=57 Runoff=1.50 cfs 0.092 of Subcatchment 13S:Watershed DA Runoff Area=7.700 ac 57.14% Impervious Runoff Depth=3.54" Tc=17.0 min CN=82 Runoff=32.91 cfs 2.271 of Subcatchment 14S:Onsite Detained Runoff Area=0.190 ac 31.58%Impervious Runoff Depth=2.69" Tc=12.0 min CN=73 Runoff=0.73 cfs 0.043 of Subcatchment 15S:X2A Runoff Area=1.550 ac 34.58% Impervious Runoff Depth=2.78" Tc=13.3 min CN=74 Runoff=5.91 cfs 0.359 af Subcatchment 16S:X2 Runoff Area=0.190 ac 81.05% Impervious Runoff Depth=4.48" Tc=5.0 min CN=91 Runoff=1.44 cfs 0.071 of Subcatchment 17S:X3 Runoff Area=1.330 ac 38.72%Impervious Runoff Depth=2.87" Tc=10.9 min CN=75 Runoff=5.70 cfs 0.318 of Pond 3:Vault Peak Elev=497.86' Storage=26 cf Inflow=4.65 cfs 0 252 af Primary=2.96 cfs 0.233 of Secondary=1.69 cfs 0.019 af Outflow=4.65 cfs 0.252 of Pond 4:Detention Peak EIev=494.30' Storage=4,292 cf Inflow=2.96 cfs 0 233 of Outflow=0.95 cfs 0.233 of Pond 7: Detention Peak Elev=492.22' Storage=706 cf Inflow=2.41 cfs 0 061 of Outflow=2.19 cfs 0 061 af Link 10:POA Inflow=17.66 cfs 1.033 of Primary=17.66 cfs 1.033 of AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 23 Link 11:Flow at Open Space Inflow=2.61 cfs 0.381 af Primary=2.61 cfs 0.381 af Link 14L:Stream Head Inflow=32.91 cfs 2.271 af Primary=32.91 cfs 2.271 af Total Runoff Area=13.797 ac Runoff Volume=3.685 af Average Runoff Depth=3.20" 56.03% Pervious=7.730 ac 43.97%Impervious=6.067 ac AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 24 Summary for Subcatchment 1: D.A. B (New Sheetflow) Runoff = 0.97 cfs @ 12.04 hrs, Volume= 0.056 af, Depth= 2.78" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description 0.240 74 Sheet Flow Adjusted CN 0.240 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.6 Direct Entry, Summary for Subcatchment 2: D.A.A Runoff = 4.65 cfs @ 12.02 hrs, Volume= 0.252 af, Depth= 3.06" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description 0.990 77 Adjusted CN 0.990 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Subcatchment 5: Onsite Not Detained (1) Runoff = 0.33 cfs @ 12.07 hrs, Volume= 0.021 af, Depth= 1.69" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description 0.150 61 >75%Grass cover, Good, HSG B 0.150 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.5 Direct Entry, AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b sin M21870 ©2020 HydroCAD Software Solutions LLC Page 25 Summary for Subcatchment 6: Offsite Not Detained (1) Runoff = 1.15 cfs @ 11.98 hrs, Volume= 0.063 at Depth= 4.70" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description * 0.140 98 Impervious 0.020 61 >75%Grass cover, Good, HSG B 0.160 93 Weighted Average 0.020 12.50%Pervious Area 0.140 87.50% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.5 Direct Entry, Summary for Subcatchment 8: On-Site Not Detained (2) Runoff = 0.78 cfs @ 11.99 hrs, Volume= 0.038 af, Depth= 2.69" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description 0.115 61 >75%Grass cover,Good, HSG B * 0.054 98 Impervious 0.169 73 Weighted Average 0.115 68.05%Pervious Area 0.054 31.95% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment 9: Off-Site Not Detained (2) Runoff = 2.11 cfs @ 11.97 hrs, Volume= 0.102 af, Depth= 3.74" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description 0.120 61 >75%Grass cover,Good, HSG B * 0.208 98 Impervious 0.328 84 Weighted Average 0.120 36.59%Pervious Area 0.208 63.41%Impervious Area AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 26 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.1 Direct Entry, Summary for Subcatchment 12S: Original Sheetflow Area Runoff = 1.50 cfs @ 12.05 hrs, Volume= 0.092 af, Depth= 1.39" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description 0.246 61 >75%Grass cover,Good, HSG B 0.554 55 Woods, Good, HSG B 0.800 57 Weighted Average 0.800 100.00%Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.6 Direct Entry, Summary for Subcatchment 13S: Watershed DA Runoff = 32.91 cfs @ 12.09 hrs, Volume= 2.271 af, Depth= 3.54" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description * 3.300 61 Turf * 4.400 98 Impervious 7.700 82 Weighted Average 3.300 42.86% Pervious Area 4.400 57.14% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.0 Direct Entry, Summary for Subcatchment 14S: Onsite Detained Runoff = 0.73 cfs @ 12.04 hrs, Volume= 0.043 af, Depth= 2.69" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 10yrRainfa11=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 27 Area(ac) CN Description * 0.060 98 Impervious 0.130 61 >75%Grass cover,Good, HSG B 0.190 73 Weighted Average 0.130 68.42%Pervious Area 0.060 31.58% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.0 Direct Entry, Summary for Subcatchment 15S: X2A Runoff = 5.91 cfs @ 12.05 hrs, Volume= 0.359 af, Depth= 2.78" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs, dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description * 0.536 98 IMPERVIOUS * 1.014 61 Turf 1.550 74 Weighted Average 1.014 65.42%Pervious Area 0.536 34.58% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.3 Direct Entry, Summary for Subcatchment 16S: X2 Runoff = 1.44 cfs @ 11.96 hrs, Volume= 0.071 af, Depth= 4.48" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description * 0.154 98 IMPERVIOUS * 0.036 61 Turf 0.190 91 Weighted Average 0.036 18.95%Pervious Area 0.154 81.05% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 28 Summary for Subcatchment 17S: X3 Runoff = 5.70 cfs @ 12.03 hrs, Volume= 0.318 af, Depth= 2.87" Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-48.00 hrs,dt=0.01 hrs Type II 24-hr 10yr Rainfall=5.51" Area(ac) CN Description * 0.515 98 IMPERVIOUS * 0.815 61 Turf 1.330 75 Weighted Average 0.815 61.28%Pervious Area 0.515 38.72%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.9 Direct Entry, Summary for Pond 3: Vault Inflow Area= 0.990 ac, 0.00%Impervious, Inflow Depth= 3.06" for 10yr event Inflow = 4.65 cfs @ 12.02 hrs, Volume= 0.252 of Outflow = 4.65 cfs @ 12.02 hrs, Volume= 0.252 af, Atten=0%, Lag=0.1 min Primary = 2.96 cfs @ 12.02 hrs, Volume= 0.233 of Secondary= 1.69 cfs @ 12.02 hrs, Volume= 0.019 af Routing by Stor-Ind method,Time Span=0.00-48.00 hrs, dt=0.01 hrs Peak Elev=497.86'@ 12.02 hrs Surf.Area= 16 sf Storage=26 cf Plug-Flow detention time=0.2 min calculated for 0.252 af(100%of inflow) Center-of-Mass det.time=0.2 min(826.1 -825.9) Volume Invert Avail.Storage Storage Description #1 496.23' 98 cf 4.00'W x 4.00'L x 6.12'H 4'x4'Vault Storage Device Routing Invert Outlet Devices #1 Primary 496.17' 15.0" Round STM 5-6 L= 182.9' Ke=0.100 Inlet/Outlet Invert=496.17'/494.80' S=0.00757 Cc=0.900 n=0.011, Flow Area= 1.23 sf #2 Device 1 496.23' 24.0"W x 3.0" H Vert.Weir Plate Orifice C=0.600 Limited to weir flow at low heads #3 Secondary 497.33' 15.0" Round STM 3-4 L=69.1' Ke=0.100 Inlet/Outlet Invert=497.33'/490.18' S=0.10351' Cc=0.900 n=0.011, Flow Area= 1.23 sf #4 Device 3 496.24' 15.0" Round STM 4-5 L= 15.7' Ke=0.100 Inlet/Outlet Invert=496.19'/496.24' S=-0.0032'/' Cc=0.900 n=0.011, Flow Area= 1.23 sf AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type I124-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 29 Primary OutFlow Max=2.95 cfs@ 12.02 hrs HW=497.86' (Free Discharge) L1=STM 5.6 (Passes 2.95 cfs of 6.50 cfs potential flow) L2=Weir Plate Orifice (Orifice Controls 2.95 cfs @ 5.91 fps) Secondary OutFlow Max=1.69 cfs @ 12.02 hrs HW=497.86' (Free Discharge) L3=STM 3-4 (Inlet Controls 1.69 cfs @ 3.39 fps) L4=STM 4-5 (Passes 1.69 cfs of 5.48 cfs potential flow) Summary for Pond 4: Detention Inflow Area= 0.990 ac, 0.00%Impervious, Inflow Depth= 2.83" for 10yr event Inflow = 2.96 cfs @ 12.02 hrs, Volume= 0.233 af Outflow = 0.95 cfs @ 12.27 hrs, Volume= 0.233 af, Atten=68°/g Lag= 15.4 min Primary = 0.95 cfs @ 12.27 hrs, Volume= 0.233 of Routing by Stor-Ind method, Time Span=0.00-48.00 hrs,dt=0.01 hrs Peak Elev=494.30'@ 12.27 hrs Surf.Area= 1,714 sf Storage=4,292 cf Plug-Flow detention time=267.6 min calculated for 0.233 af(100%of inflow) Center-of-Mass det.time=267.8 min( 1,102.2-834.4) Volume Invert Avail.Storage Storage Description #1 489.70' 2,936 cf Gravel(Prismatic)Listed below(Recalc) 9,256 cf Overall- 1,917 cf Embedded=7,339 cf x 40.0%Voids #2 489.70' 1,917 cf StormTech MC-4500 x 18 Inside#1 Effective Size=90.4"W x 60.0"H =>26.46 sf x 4.03'L= 106.5 cf Overall Size= 100.0"W x 60.0"H x 4.33'L with 0.31'Overlap 4,852 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 489.70 1,714 0 0 495.10 1,714 9,256 9,256 Device Routing Invert Outlet Devices #1 Primary 494.25' 32.0' long x 3.7'breadth Emergency Spillway Head(feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2,00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef.(English) 2.40 2.55 2.69 2.68 2.66 2.66 2.65 2.67 2.67 2.69 2.75 2.79 2.82 2.87 3.01 3.14 3.32 #2 Primary 489.70' 3.0" Round Culvert L= 110.0' Ke=0.800 Inlet/Outlet Invert=489.70'/488.00' S=0.0155'/' Cc=0.900 n=0.015, Flow Area=0.05 sf Primary OutFlow Max=0.90 cfs@ 12.27 hrs HW=494.29' (Free Discharge) L1=Emergency Spillway (Weir Controls 0.73 cfs @ 0.51 fps) 2=Culvert (Barrel Controls 0.17 cfs @ 3.54 fps) AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type II 24-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 30 Summary for Pond 7: Detention Inflow Area= 0.190 ac, 31.58%Impervious, Inflow Depth = 3.86" for 10yr event Inflow = 2.41 cfs @ 12.02 hrs, Volume= 0.061 af Outflow = 2.19 cfs @ 12.05 hrs, Volume= 0.061 af, Atten=9%, Lag= 1.8 min Primary = 2.19 cfs @ 12.05 hrs, Volume= 0.061 af Routing by Stor-Ind method, Time Span=0.00-48.00 hrs,dt=0.01 hrs Peak Elev=492.22'@ 12.05 hrs Surf.Area=456 sf Storage=706 cf Plug-Flow detention time=(not calculated:outflow precedes inflow) Center-of-Mass det.time=18.8 min (820.9-802.1 ) Volume Invert Avail.Storage Storage Description #1 490.03' 29 cf 15.0" Round 15"Storage L=23.4' S=0.0098'/' #2 490.26' 1,433 cf 48.0" Round 48"Storage x 3 L=38.0' S=0.0025'/' 1,461 cf Total Available Storage Device Routing Invert Outlet Devices #1 Primary 489.33' 15.0" Round Pipe 2-1 L= 123.9' Ke=0.600 Inlet/Outlet Invert=489.33'/482.35' S=0.0563'I' Cc=0.900 n=0.011, Flow Area= 1.23 sf #2 Device 1 489.53' 2.0"Vert. 1-yr Orifice C=0.600 Limited to weir flow at low heads #3 Device 1 491.93' 48.0"W x 5.0" H Vert. 10-yr Orifice C=0.600 Limited to weir flow at low heads Primary OutFlow Max=2.18 cfs@ 12.05 hrs HW=492.22' (Free Discharge) L1=Pipe 2-1 (Passes 2.18 cfs of 8.34 cfs potential flow) '-2=1-yr Orifice (Orifice Controls 0.17 cfs @ 7.77 fps) 3=10-yr Orifice (Orifice Controls 2.01 cfs @ 1.73 fps) Summary for Link 10: POA Inflow Area= 4.067 ac, 40.99%Impervious, Inflow Depth= 3.05" for 10yr event Inflow = 17.66 cfs @ 12.03 hrs, Volume= 1.033 of Primary = 17.66 cfs @ 12.03 hrs, Volume= 1.033 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-48.00 hrs, dt=0.01 hrs Summary for Link 11: Flow at Open Space Inflow Area= 2.030 ac, 0.00%Impervious, Inflow Depth= 2.26" for 10yr event Inflow = 2.61 cfs @ 12.05 hrs, Volume= 0.381 af Primary = 2.61 cfs @ 12.05 hrs, Volume= 0.381 af, Atten=0%, Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-48.00 hrs, dt=0.01 hrs AMENDED ASBUILT HILLBROOK ASBUILT AMENDED POSTDEV HYDROCAD Type 1124-hr 10yr Rainfall=5.51" Prepared by Shimp Engineering Printed 3/6/2020 HydroCAD®10.10-3b s/n M21870 ©2020 HydroCAD Software Solutions LLC Page 31 Summary for Link 14L: Stream Head Inflow Area= 7.700 ac, 57.14%Impervious, Inflow Depth= 3.54" for 10yr event Inflow = 32.91 cfs @ 12.09 hrs, Volume= 2.271 af Primary = 32.91 cfs @ 12.09 hrs, Volume= 2.271 af, Atten=0°/q Lag=0.0 min Primary outflow= Inflow,Time Span=0.00-48.00 hrs, dt=0.01 hrs Runoff Quality Calculations: VRRM New Development Spreadsheet Virginia Runoff Reduction Method Worksheet Virginia Runoff Reduction Method New Development Worksheet-v2.8-June 2014 Site Data Summary Total Rainfall= 43 inches Site Land Cover Summary A Soils B Soils C Soils D Soils Total %of Total Forest(acres) 0 00 0 54 0 00 0 00 0 54_ 21 52 Turf(acres) 0 00 1 26 0 00 0 00 1 26 49 74 Impervious(acres) 0 00 0 73 0 00 0 00 0 73 28 73 2 53 100 00 Site Rv 0 38 Post Development Treatment Volume(ft3) 3476 Post Development TP Load(Ib/yr) 2.18 Post Development TN Load(lb/yr) 15.62 Total TP Load Reduction Required(lb/yr) 1.15 Total Runoff Volume Reduction(ft3) 207 Total TP Load Reduction Achieved(Ib/yr) 0 Total TN Load Reduction Achieved(Ib/yr) 1 86 Adjusted Post Development TP Load(Ib/yr) 2 05 Remaining Phosphorous Load Reduction(Lb/yr)Required 1 02 Drainage Area Summary D.A.A D.A.B D.A.C D.A.D D.A.E Total Forest(acres) 0.00 0 00 0 00 0 00 0 00 0 00 Turf(acres) 0 53 0.15 0.00 0.00 0 00 0 68 Impervious(acres) 0 46 0.09 0 00 0 00 0 00 0.55 1.23 Drainage Area Compliance Summary D.A.A D.A.B D.A.C D.A.D D.A.E Total TP Load Red.(Ib/yr) 0 10 0 03 0 00 0 00 0.00 0.13 TN Load Red.(Ib/yr) 1.39 0 46 0 00 0 00 0.00 1.86 Summary Print Virginia Runoff Reduction Method Worksheet Drainage Area A Summary Land Cover Summary A Soils B Soils C Soils D Soils Total %of Total Forest(acres) 0 00 0.00 0.00 0 00 0 00 0.00 Turf(acres) 0.00 0.53 0.00 0 00 0 53 53.54 Impervious(acres) 0.00 0 46 0 00 0 00 0 46 46.46 0 99 BMP Selections Practice Credit Area(acres) Downstream Practice 2.a.Simple Disconnection to A/B Soils(Spec#1) impervious 0.09 None acres disconnected Total Impervious Cover Treated(acres) 0.09 Total Turf Area Treated(acres) 0 00 Total TP Load Reduction Achieved in D.A.A(Ib/yr) 0 10 Total TN Load Reduction Achieved in D.A.A(Ib/yr) 1 39 Summary Print Virginia Runoff Reduction Method Worksheet Drainage Area B Summary Land Cover Summary A Soils B Soils C Soils D Soils Total %of Total Forest(acres) 0 00 0 00 0 00 0 00 0 00 0 00 Turf(acres) 0.00 0 15 0.00 0 00 0 15 62 50 Impervious(acres) 0.00 0 09 0.00 0 00 0 09 37 50 0 24 BMP Selections Practice Credit Area(acres) Downstream Practice 2.a.Simple Disconnection to A/B Soils(Spec#1) impervious 0.03 None acres disconnected Total Impervious Cover Treated(acres) 0.03 Total Turf Area Treated(acres) 0 00 Total TP Load Reduction Achieved in D.A.A(Ib/yr) 0 03 Total TN Load Reduction Achieved in D.A.A(Ib/yr) 0 464 Summary Print Virginia Runoff Reduction Method Worksheet Channel and Flood Protection Weighted CN 1-year 2-year storm 10-year storm Adjusted CN storm Adjusted Adjusted CN CN Target Rainfall Event(in) 3.01 3 65 5 51 D A A CN 78 77 77 77 D A B CN 75 74 74 74 D A C CN 0 UN/A UN/A #N/A D A.D CN 0 #N/A UN/A UN/A D.A.E CN 0 #N/A UN/A UN/A Summary Print