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HomeMy WebLinkAboutRESOLUTION NO. 2018-06 RESOLUTION NO. 2018-06 RESOLUTION APPROVING THE PRIVATE STORM WATER DETENTION POND AT LOT 2 OF KARAL'S SECOND ADDITION (21 WILLIAMS BOULEVARD) WHEREAS, Steve and Teresa Waln,Owners of Waln Repair and Collision Center and Lot 2 of Karal's Second Addition (21 Williams Boulevard) have expanded their commercial business over the years with numerous building and parking lot expansions; and WHEREAS, Chapter 100, Storm Water Management of the City's Code of Ordinances requires commercial businesses to mitigate storm water run-off from their developed sites; and WHEREAS, Doug Brain with Brain Engineering, Inc. has submitted a Site Plan of Improvements and a drainage report for a private storm water detention pond located in the southwest corner of Lot 2, Karal's Second Addition(21 Williams Boulevard) on behalf of Steve and Teresa Waln; and WHEREAS, this private detention pond is limited in its storm water detention capacity due to the existing downstream site conditions, the terrain at Lot 2 of Karal's Second Addition(21 Williams Boulevard), and the building elevations of Waln Repair and Collision Center at 21 Williams Boulevard; and WHEREAS, Hall and Hall Engineers, Inc. has reviewed the Site Plan of Improvements and the drainage report for this private storm water detention pond on Lot 2 of Karal's Second Addition(21 Williams Boulevard) and has recommended approval of this private storm water detention pond. NOW, THEREFORE BE IT RESOLVED, by the City Council of the City of Fairfax, Iowa, that the private storm water detention pond on Lot 2 of Karal's Second Addition (21 Williams Boulevard) is hereby acknowledged and approved on the part of the City of Fairfax, Linn County, Iowa. BE IT FURTHER RESOLVED, by the City Council of Fairfax, Iowa, that the Mayor and the City Clerk/Treasurer are hereby authorized and directed to execute said Resolution. Passed and approved this 13t" day of February, 2018. AYES: Otto, Kell, Volk, and Wainwright NAYS: None ABSTAIN: Daly. Mike Daly abstained because he is employed at Waln Repair and Collision Center. "3 K Burnell G. Frieden, Mayor ATTEST: / k,w44xti 61 ta95/ �*N C"nthia Stimson, City Clerk/Treasurer rr� �� yY �♦* 'May yi 0011 0000 0, HALL & HALL ENGINEERS, . Leaden in Land Deve/olmiew Since 1953 February 13, 2018 Honorable Mayor and City Council Members City of Fairfax, Iowa Re: Consideration of the private storm water detention pond improvements to Lot 2, Karal's Second Addition (21 Williams Boulevard) Honorable Mayor Frieden and City Council Members, Due to the numerous building and parking lot additions to Waln's Auto Shop, a private storm water detention pond is required at this site per Chapter 100 —Storm Water Management of the City's Code of Ordinances. This detention pond is designed to detain the 10-year storm event at this private detention pond, which is located at the southwest corner of the site. The 25-year storm event begins to overtop the existing pond berm, which is the parking lot/drive located on the adjacent site (Melody Vances storage garage site). This private detention pond is limited in its storm water detention capacity due to the existing downstream site conditions, the terrain at 21 Williams Boulevard, and the building elevations of Waln's Auto shop at 21 Williams Boulevard. I have reviewed the site plan of improvements and the drainage report for this private detention pond and recommend that the City Council approves these proposed improvements to the Waln's private detention pond. Respectf Submitted, Shane R. Wicks, P.E. Hall and Hall Engineers, Inc. CC: Doug Brain, P.E. Brain Engineering, Inc. Bernie Frieden, Fairfax Mayor Chris Philipp, Fairfax Building Supervisor Lynn Miller, Fairfax Maintenance Supervisor. Kevin Stensland, Fairfax Utilities Supervisor Cynthia Stimson, Fairfax City Clerk/Treasurer Encl's. —Site Plan of Improvement and Drainage Report CIVIL ENGINEERING • LAND SURVEYING • LAND DEVELOPMENT PLANNING • LANDSCAPE ARCHITECTURE 1860 Boyson Road • Hiawatha,IA 52233 • Ph:319.362.9548 • Fx:319.362.7595 • www.halleng.eom LOCATON MAP SITE PLAN LOT 2,KARAL'S SECOND ADDITION N€ J� SITE LOC TION �S' rh5 e�m LEGAL DESCRIPTION b 4 O E�.woo ENG'NEER ,0,0QW S 2NDADD—N ING INC 1—Doh� Loe w< swaz —GRll GC. re.z—EaN .. . 7ERESI_N OOIR DS�o O'N —IT-1Iowa n<0z ]� omav 'a •�.�_ LOT7071T 11111 S�17 11 b EASING 1 CO—ED ---- - = 0' � yyo noomoN EXIS 70" ENSPSCALE 1" 2 O LOT 4 —11050-7o _n,� N 11— 'U70 707,PR zz HNa,�oo�PROVIDED_,�a g o Os CLw El Ld R—ADINFERORA �aRas — N i3O.au.Eoio�.Na.00v.NaOE REa�a�000 . boe-(two 8 t 4 t& o I y901 n 2 I—IP �T��G"�T%��-11 ITI 11 TI I GR.Ill G�l 1,1 ITI III�IRI I T.RI I I III III IT.I�-1.IIIITI ,.R R�X ­ETE i �� IIIE.EIT 2 PROOF ROLL—F L-1-0—ITFI—TOR—TURB�,IR'O.F'IRTOHLIL G R�­ I "'L�,R,"0, R"0 �IUTBH 2 T 0 1 Ul,'I'U'IUl TG'OLI' IHIILI IlIGHT RI OF"IUBGR—I-H—101 OR Ul IT-1 TO IIIIT IPI IIF-LIIIITI "T T 'I R F�OIIT�01' %R.—.TO�l PT"HO"T 1.2FI��LHLI 1�1,1—T T� —I—R�PR.IT.R R RT_ --I' 2ND I �OTII.P—p—,TF.LL"IIUTIT=IRIG lF,—R—Il"�TTH, 1� ,.'R T"'T" DDRII.1 IITH III IP I I F11�Llll ITI LOT3 I PR.TF'RI'RGR."I'TT.�'PTTH'.FT IIH I'IHIRI T PI L I IIH IULI I I I I IIIIHI RI oFSRR D-R �IL�P,I I IIT U 111 Fl R HIULI IIG 11 ft RGI'TI'IRII'TIRTII"'.TFHRIRI LFFTIIRI.IUURUIBIITHILBITI 0 0 " OL 0-0— O—%XTURRLIUFRPII.F R' ZONED C-2 "H�H, GR T T,12 TH Tl%TI1R,F'1,�T ='ITl T H wl,.IRF TH I R.I K I.R LU 1,1 P I IH IL B I IRG I R R. 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WIIIE RN� RCE W,��RC� W, 7 6 2 2 E is STORMWATER SUMMARY REPORT I i 21 Williams Boulevard City of Fairfax, Iowa r January 4, 2018 ,_ c I i BRAIN ENGINEERING, INC. 1540 Midland Court NE, Cedar Rapids, Iowa j r I hereby certify that this engineering document was prepared by me or under my direct personal supervision and that I am a duly licensed Professional Engineer under the laws of the State of Iowa. � I Executed at Cedar Rapids,Iowa this day of '2018. i 1 \\\\\I\II1111111III0j1j, � ��� Douglas F.Brain,P.E.No.20267 o 'o ® My license renewal date is December 31,2018 DOUGLAS F. eG?o 4 BRAIN °Z= a ° 20267 .� • • c 1. Executive Summary Lot 2, Karal's 2nd Addition encompasses 2.13 acres and is currently developed. When the site was originally developed, the site had a total of 18,143 square feet of hard surfacing. The site has been developed from the original site, and the existing development now has 37,116 square feet of structures and hard surfacing. The proposed development will add a building addition to the rear of the existing building. The proposed development will increase the hard surfacing to 39,800 square feet. The site drains to a 15" HDPE culvert located in the southwest corner of the site. The 15" HDPE culvert drains into a drainage way located southwest of the site. 2.90 acres of offsite drainage, north and east of the site, currently drains through the east part of the site and through the drainage way located on the south side of the site. The proposed detention basin will berm the offsite flow and the offsite flow will drain along the east property line to the existing swale south of the site. The existing 15" HPDE culvert will be extended to the south property line. The culvert will have a reinforced concrete flared end section placed at the end of the culvert. The flared end section will have a wall placed in front of it. The well will extend seven inches past the flow line of the flared end section and have two 3/" holes placed at the flow line. Table 1: Runoff Summary Site Area-2.13 acres Onsite Contributing Offsite Runoff Recurrence Original Developed Full Developed Site Existing Discharge Pond Interval Peak Discharge Peak Discharge (cfs) Discharge cfs) (cfs) (cfs 2 yr 1.80 2.48 3.70 2.58 5 yr 2.91 3.72 5.36 3.60 10 yr 4.00 4.91 6.93 4.23 25 yr 5.77 6.79 9.36 6.02 50 yr 1 7.31 8.38 11.42 8.91 100 yr 9.03 10.15 13.68 11.88 Table 2: Allowable Release Rate Allowable Release On Site Pre-Developed Peak Contributing Off Site Developed Peak Rate Discharge Rate-5 yr Discharge to Basin- 100 yr cfs 16.59 = 2.91 + 13.68 2 Basin: Stage Storage Inflow Outflow Elevation—ftcubic feet) (cfs) (cfs 753.75 0 0 0 754.00 217 0.10 0.02 754.50 3,537 1.79 1.47 755.00 9,958 16.17 3.35 755.50 18,780 23.51 5.06 755.84* 27,878 11.88 11.88 760.00 32,994 *1 00-year storm elevation. 2. Site Characteristics ■ EXISTING CONDITIONS Lot 2, Karat's 2nd Addition encompasses 2.13 acres and is currently developed. When the site was originally developed, the site had a total of 18,143 square feet of hard surfacing. The site has been developed from the original site, and the existing development now has 37,116 square feet of structures and hard surfacing. The site drains to a 15" HDPE culvert located in the southwest corner of the site. The 15" HDPE culvert drains into a drainage way located west of the site. 2.90 acres of offsite drainage, north and east of the site, currently drains through the east part of the site and through the drainage way located on the south side of the site. The majority of the site consists of Atterberry silt loam, a Hydrologic Group C. ■ PROJECT SUMMARY, POST-DEVELOPED CONDITIONS Lot 2, Karat's 2nd Addition encompasses 2.13 acres and is currently developed. When the site was originally developed, the site had a total of 18,143 square feet of hard surfacing. The site has been developed from the original site and the existing development now has 31,893 square feet of structures and hard surfacing. The proposed development will add paving to the east and south of the existing parking lot. The proposed development will increase the hard surfacing to 37,317 square feet, and the site will be designed for a future building addition that will increase the total hard surfacing to 40,872 square feet. The site drains to a 15" HDPE culvert located in the southwest corner of the site. The east side of the proposed pond will be bermed to direct storm water from 1.50 acres of offsite drainage to the south. The proposed detention basin will be located east and south of the existing parking lot. The proposed detention basin will collect storm water from the parking lot, the east drain spouts of the existing building, down spouts from the future building addition and the east side of the site. The west side of the site will drain to a proposed swale located between the future building addition and the west property line. The west swale will drain south to the existing 15" HDPE culvert. 3 ■ CONTRIBUTING OFF-SITE DRAINAGE Off-site drainage flow comes from the northeast and east. The northeast drainage area (1.50 acres) is a vacant lot that will flow directly to the northeast corner of the proposed pond. The east side of the proposed basin will be bermed to direct the offsite flow along the east property line to the existing swale south of the site. 3. Pre-Development Runoff Analysis ■ Watershed Area The site is 2.13 acres. The original development will be used as the predeveloped site. ■ Time of Concentration The total time of concentration in 16.4 minutes. See Appendix for time of concentration information. ■ Precipitation Model The precipitation model used for this site is the SCS Type-II Distribution. Rainfall amounts for a given recurrence interval are as follows: 5-yr= 3.75 inches 10-yr= 4.42 inches 25-yr= 5.44 inches 50-yr= 6.29 inches 100-yr = 7.22 inches ■ Rainfall Loss Method The curve number used used for the original ground cover is 74, greater than 75% grass covered with class C soil. ■ Runoff Model The runoff model used is the SCS TR-20 Model. The calculations are created by using the HydroCAD Stormwater Modeling System. ■ Summary of Pre-Development Runoff Drainage Area C Time of Concentration Recurrence Peak Outflow Acres (minutes) Interval (cfs) ears 2.13 74 16.4 5 2.91 2.13 74 16.4 10 4.00 2.13 74 16.4 25 5.77 2.13 74 16.4 50 7.31 2.13 74 16.4 100 9.03 4 4. Post-Development Runoff Analysis • Watershed Area The site is 2.13 acres • Time of Concentration The precipitation model used for this site is the SCS Type-II Distribution. Rainfall amounts for a given recurrence interval are as follows: 5-yr= 3.75 inches 10-yr= 4.42 inches 25-yr= 5.44 inches 50-yr= 6.29 inches 100-yr = 7.22 inches ■ Rainfall Loss Method The curve number is 79, 50-75% grass cover with class C soil. ■ Runoff Model The runoff model used is the SCS TR-20 Model. The calculations are created by using the HydroCAD Stormwater Modeling System. ■ Summary of Post-Development Runoff Drainage Area CN Time of Recurrence Peak Outflow (Acres) Concentration Interval (cfs) (minutes) (years) 2.13 79 16.4 5 5.36 2.13 79 16.4 10 6.93 2.13 79 16.4 25 9.36 2.13 79 16.4 50 11.42 2.13 79 16.4 100 13.68 5. Storm Water Conveyance Design • Design Standards Used Cedar Rapids Metropolitan Area Engineering Design Standards. • Storm Sewer N/A 5 • Culverts The existing 15" culvert located in the southwest corner of the site will be modeled as a detention basin. • Open Channel Flow There will be a proposed swale between the future building addition and west property line. The swale will be designed to carry the 100-year storm event from the westerly southwest corner of the existing building to the existing 15" HDPE culvert located near the southwest corner of the site. Storm Drainage Outlets and Downstream Analysis The 15" HDPE culvert in the southwest corner of the site empties into a drainage way located west of the neighboring site to the west. Hydraulic Model Hydraulic modeling was not used for this site. 6. Stormwater Management Design • Design Standards Used Cedar Rapids Metropolitan Area Engineering Design Standards. • Detention Basin Location The detention basin is located in the southwest corner of the site. • Basin Performance Basin: Stage Storage Inflow Outflow Elevation—ftcubic feet) (cfs) (cfs 753.75 0 0 0 754.00 217 0.10 0.02 754.50 3,537 1.79 1.47 755.00 9,958 16.17 3.35 755.50 18,780 23.51 5.06 755.84* 27,878 11.88 11.88 760.00 32,994 *1 00-year storm elevation. 6 • Basin Outlet The proposed detention basin outlet consists of a flared end section with a 7" high wall in front of the flared end section. The wall will have 2-0.8" at 753.75 and the top of the flared end section will remain open. The overflow will be established at an elevation of 755.30. • Spillway and Embankment Protection None will be used. • Method Used for Detention Basin Sizing The detention basin was preliminarily sized using the Modified Rational Method, 9,375 cubic feet. However final design was determined through hydrograph routing utilizing HydroCAD and the Rational Method. • Water Quality Design Standard Total area of site = 92,850 square feet. Total volume required = 93,100 sq. feet X 0.083 feet = 7,707 cubic feet. Total storage provided = 14,849 cubic feet at 755.30. I. Permits City of Cedar Rapids Minor Erosion Control Permit will be required. A Pollution Prevention Plan is included in the plan set. II. References SCS, Soil Survey of Linn County, circa 1979. Bulletin 71, Rainfall Frequency Atlas of the Midwest, circa 1992. Table 2B-2.07: of the SUDAS Design Manual. III. Appendix A. Exhibits and Calculations PRE-DEVELOPED INFORMATION (HYDROCAD OUTPUT) 8 5 Year original developed site 357817-10 WALN UPDATE Type 1124-hr Rainfall=3.75" Prepared by {enter your company name here} Printed 1/4/2018 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 1 Summary for Subcatchment 3S: Original Developed Site Runoff = 2.91 cfs @ 12.18 hrs, Volume= 0.251 af, Depth= 1.42" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr Rainfall=3.75" Area (ac) CN Description 2.130 74 >75% Grass cover, Good, HSG C 2.130 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.6 50 0.0100 0.11 Sheet Flow, Grass: Short n= 0.150 P2= 3.06" 16.2 500 0.0054 0.51 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 23.8 550 Total Subcatchment 3S: Original Developed Site Hyd rog raph ❑Runoff 3... 2.91 cfs Type 11 24-h r Raiufal1-3 75 Rd n off Area-2.130 ac 2..x- Runoff Valume0.251 af,,....... Runoff Depth=1.42 FI©w Length:550' TG=23-8 ::m: ih 1.. CN-74 0_. 5 6 7 8 9 1011 12131415 1617181920 2122 2324 2526 2728 2930 3132 33 34353637 3839 404142 434445 4647 48 Time (hours) 100-Year Original Developed Site 357817-10 WALN UPDATE Type 1124-hr Rainfall=7.22" Prepared by {enter your company name here} Printed 1/4/2018 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 1 Summary for Subcatchment 3S: Original Developed Site Runoff = 9.03 cfs @ 12.17 hrs, Volume= 0.752 af, Depth= 4.23" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr Rainfall=7.22" Area (ac) CN Description 2.130 74 >75% Grass cover, Good, HSG C 2.130 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.6 50 0.0100 0.11 Sheet Flow, Grass: Short n= 0.150 P2= 3.06" 16.2 500 0.0054 0.51 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 23.8 550 Total Subcatchment 3S: Original Developed Site Hyd rog raph 10 ❑Runoff .... .... 9.03 cfs , .... ......., 1 ,.... ......., 1 ,.... ,......., ,........ 9mx TYhc I1 24-hr 8 Rainfall=722". 7 Ru h off Area=2.1 30ac,,,...... ...... Runoff Voiarr�e^Q.752 air . 6-' Runoff Depth=4.23". . ° 5m Flo: *.Length=550LL '. . 4-: 23-8 :M: in 3. +CN-74 2- 0- 5 0.5 6 7 8 9 101112131415161718192021222324252627282930313233343536373839404142434445464748 Time (hours) POST-CONSTRUCTION INFORMATION (HYDROCAD OUTPUT) 9 5 year developed site 357817-10 WALN UPDATE Type 1124-hr Rainfall=3.75" Prepared by {enter your company name here} Printed 1/4/2018 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 1 Summary for Subcatchment 8S: Proposed Developed Site Runoff = 3.72 cfs @ 12.18 hrs, Volume= 0.313 af, Depth= 1.76" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr Rainfall=3.75" Area (ac) CN Description 2.130 79 50-75% Grass cover, Fair, HSG C 2.130 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.6 50 0.0100 0.11 Sheet Flow, Grass: Short n= 0.150 P2= 3.06" 16.2 500 0.0054 0.51 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 23.8 550 Total Subcatchment 8S: Proposed Developed Site Hyd rog raph f .. ..... . ..... ..... ..... ..... ,....... ❑Runoff 4- 3.72 cfs Type 11 24-h r Rainfall-3 75 3-- Rd n aff Area-2.130 40 Runoff Valume^0.313 of 3 Ot2 FIaWr Length=550' TC=23.8 rnin 74 0... 5 6 7 8 9 1011 12131415 161718192021222324252627282930313233343536373839404142434445464748 Time (hours) 100-year hydrocad developed 357817-10 WALN UPDATE Type 1124-hr Rainfall=7.22" Prepared by {enter your company name here} Printed 1/4/2018 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 1 Summary for Subcatchment 8S: Proposed Developed Site Runoff = 10.15 cfs @ 12.17 hrs, Volume= 0.850 af, Depth= 4.79" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr Rainfall=7.22" Area (ac) CN Description 2.130 79 50-75% Grass cover, Fair, HSG C 2.130 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.6 50 0.0100 0.11 Sheet Flow, Grass: Short n= 0.150 P2= 3.06" 16.2 500 0.0054 0.51 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 23.8 550 Total Subcatchment 8S: Proposed Developed Site Hyd rog raph 11_.x ❑Runoff L... ; 10.15 cfs ..; L......; ..; ;.. 10 m Type 1124-h 9-. Ra: ,f $. Runoff Area=2.10 ac 7 x , Runoff Valurne^0.850 of . " Runoff Depth=479"; . 5m Flow...Length=550il: '........ ... 4- G= fYlin ...... ..... CN-79 3 . . .... 2- 0..:. 5 6 7 8 9 101112131415161718192021222324252627282930313233343536373839404142434445464748 Time (hours) DRAINAGE AREA EXHIBITS 10 8S 5S Offsite Proposed Devel ed Site 4P (new Pond) �ca Reach on LInK Routing Diagram for 357817-10 WALN UPDATE Prepared by{enter your company name here}, Printed 1/4/2018 HydroCAD®10.00 s/n 00656 ©2011 HydroCAD Software Solutions LLC 5-year pond developed site 357817-10 WALN UPDATE Type 1124-hr Rainfall=3.75" Prepared by {enter your company name here} Printed 1/4/2018 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 2 Summary for Subcatchment 5S: Offsite Runoff = 5.36 cfs @ 12.21 hrs, Volume= 0.481 af, Depth= 1.99" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr Rainfall=3.75" Area (ac) CN Description 1.400 91 Urban industrial, 72% imp, HSG C 1.500 74 >75% Grass cover, Good, HSG C 2.900 82 Weighted Average 1.892 65.24% Pervious Area 1.008 34.76% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.8 50 0.0200 0.14 Sheet Flow, Grass: Short n= 0.150 P2= 3.06" 21.0 710 0.0065 0.56 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 26.8 760 Total Subcatchment 5S: Offsite Hydrograph 6... ❑Runoff 5.36 cfs 5 Rainfall:- 7 ,f 4. Runoff Valume^0.481 of N 3 3-°x FIaW Le: ngth:760' TC--26-8rrYi zn ON 82 1-. r 0_. 5 6 7 8 9 1011 12131415 161718192021222324252627282930313233343536373839404142434445464748 Time (hours) 5-year pond developed site 357817-10 WALN UPDATE Type 1124-hr Rainfall=3.75" Prepared by {enter your company name here} Printed 1/4/2018 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment 8S: Proposed Developed Site Runoff = 3.72 cfs @ 12.18 hrs, Volume= 0.313 af, Depth= 1.76" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr Rainfall=3.75" Area (ac) CN Description 2.130 79 50-75% Grass cover, Fair, HSG C 2.130 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.6 50 0.0100 0.11 Sheet Flow, Grass: Short n= 0.150 P2= 3.06" 16.2 500 0.0054 0.51 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 23.8 550 Total Subcatchment 8S: Proposed Developed Site Hyd rog raph f .. ..... . ..... ..... ..... ..... ,....... ❑Runoff 4- 3.72 cfs Type 11 24-h r Rainfall-3 75 3-- Rd n aff Area-2.130 40 Runoff Valume^0.313 of 3 Ot2 FIaWr Length=550' TC=23.8 rnin 74 0... 5 6 7 8 9 1011 12131415 161718192021222324252627282930313233343536373839404142434445464748 Time (hours) 5-year pond developed site 357817-10 WALN UPDATE Type 1124-hr Rainfall=3.75" Prepared by {enter your company name here} Printed 1/4/2018 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 4 Summary for Pond 4P: (new Pond) Inflow Area = 5.030 ac, 20.04% Impervious, Inflow Depth = 1.89" Inflow = 9.05 cfs @ 12.19 hrs, Volume= 0.794 of Outflow = 3.60 cfs @ 12.54 hrs, Volume= 0.779 af, Atten= 60%, Lag= 21.0 min Primary = 3.60 cfs @ 12.54 hrs, Volume= 0.779 of Secondary= 0.00 cfs @ 5.00 hrs, Volume= 0.000 of Routing by Stor-Ind method, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 755.07' @ 12.54 hrs Surf.Area= 0 sf Storage= 11,174 cf Plug-Flow detention time= 115.6 min calculated for 0.778 of (98% of inflow) Center-of-Mass det. time= 105.6 min ( 953.0 - 847.4 ) Volume Invert Avail.Storage Storage Description #1 753.75' 32,994 cf Custom Stage Data Listed below Elevation Cum.Store (feet) (cubic-feet) 753.75 0 754.00 217 754.50 3,537 755.00 9,958 755.30 14,849 755.50 18,780 755.75 24,894 756.00 32,994 Device Routing Invert Outlet Devices #1 Primary 753.75' 15.0" Round Culvert L= 102.0' RCP, mitered to conform to fill, Ke= 0.700 Inlet/ Outlet Invert= 753.75' /753.43' S= 0.0031 T Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.23 sf #2 Device 1 753.75' 0.8"Vert. Orifice/Grate X 2.00 C= 0.600 #3 Device 1 754.33' 15.0" x 27.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Secondary 755.45' 10.0' long x 70.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Primary OutFlow Max=3.60 cfs @ 12.54 hrs HW=755.07' (Free Discharge) L1=Culvert (Barrel Controls 3.60 cfs @ 3.45 fps) �__3=Orifi 2=Orifice/Grate (Passes < 0.04 cfs potential flow) ce/Grate (Passes < 11.68 cfs potential flow) Secondary OutFlow Max=0.00 cfs @ 5.00 hrs HW=753.75' (Free Discharge) L4=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) 5-year pond developed site 357817-10 WALN UPDATE Type 1124-hr Rainfall=3.75" Prepared by {enter your company name here} Printed 1/4/2018 HydroCAD® 10.00 s/n 00656 ©2011 HydroCAD Software Solutions LLC Page 5 Pond 4P: (new Pond) Hydrograph f'l In Inflow 9.05 as U111)Ouff low Inflow Area-5.030 ac Primary 10 x, ..... I Secondary ... .... .., Z Peak Elev=755 :07- 9. ..... ..... St fad a=11}_174_cf 8mx ..... . x,.. f�r 6 ..... 3 Sm'm _ 3 60 ds" 0 LL f. 3.60 ds x x r, 3 ...... w w 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) 8S 5S Offsite Proposed Devel ed Site 4P (new Pond) �ca Reach on LInK Routing Diagram for 357817-10 WALN UPDATE Prepared by{enter your company name here}, Printed 1/4/2018 HydroCAD®10.00 s/n 00656 ©2011 HydroCAD Software Solutions LLC 100 year hydrocad developed pond 357817-10 WALN UPDATE Type 1124-hr Rainfall=7.22" Prepared by {enter your company name here} Printed 1/4/2018 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 2 Summary for Subcatchment 5S: Offsite Runoff = 13.68 cfs @ 12.20 hrs, Volume= 1.238 af, Depth= 5.12" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr Rainfall=7.22" Area (ac) CN Description 1.400 91 Urban industrial, 72% imp, HSG C 1.500 74 >75% Grass cover, Good, HSG C 2.900 82 Weighted Average 1.892 65.24% Pervious Area 1.008 34.76% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.8 50 0.0200 0.14 Sheet Flow, Grass: Short n= 0.150 P2= 3.06" 21.0 710 0.0065 0.56 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 26.8 760 Total Subcatchment 5S: Offsite Hyd rog raph 15-'m' ❑Runoff 13.68 cfs .. ..... .... ...., 14- Type 11 24:::: -h r 13-. 12-':'` Ra:infa'l1=7.22"*...... Rw naff / Pe1-2.900 c'lC+...... 10mxm f Runoff VQlurne^1.238 0 - 9-: $: Runoff Depth=5.12'7. . 7: F.IOW.._Len_gth=760'LL ... 6-.` Td-26.8 :'., i n........ 5.'m` Q 4. ...... U1 *82........ ..... 3- 2-. 0-1 2- . " 5 6 7 8 9 10 1112 13 141516 17 1819 20 2122 23 24 25 26 27 28 29 30 3132 33 34 Time (hours) 100 year hydrocad developed pond 357817-10 WALN UPDATE Type 1124-hr Rainfall=7.22" Prepared by {enter your company name here} Printed 1/4/2018 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment 8S: Proposed Developed Site Runoff = 10.15 cfs @ 12.17 hrs, Volume= 0.850 af, Depth= 4.79" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr Rainfall=7.22" Area (ac) CN Description 2.130 79 50-75% Grass cover, Fair, HSG C 2.130 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.6 50 0.0100 0.11 Sheet Flow, Grass: Short n= 0.150 P2= 3.06" 16.2 500 0.0054 0.51 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 23.8 550 Total Subcatchment 8S: Proposed Developed Site Hyd rog raph 11_.x ❑Runoff L... ; 10.15 cfs ..; L......; ..; ;.. 10 m Type 1124-h 9-. Ra: ,f $. Runoff Area=2.10 ac 7 x , Runoff Valurne^0.850 of . " Runoff Depth=479"; . 5m Flow...Length=550il: '........ ... 4- G= fYlin ...... ..... CN-79 3 . . .... 2- 0..:. 5 6 7 8 9 101112131415161718192021222324252627282930313233343536373839404142434445464748 Time (hours) 100 year hydrocad developed pond 357817-10 WALN UPDATE Type 1124-hr Rainfall=7.22" Prepared by {enter your company name here} Printed 1/4/2018 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 4 Summary for Pond 4P: (new Pond) Inflow Area = 5.030 ac, 20.04% Impervious, Inflow Depth = 4.98" Inflow = 23.71 cfs @ 12.18 hrs, Volume= 2.088 of Outflow = 11.88 cfs @ 12.46 hrs, Volume= 2.072 af, Atten= 50%, Lag= 16.3 min Primary = 5.26 cfs @ 12.46 hrs, Volume= 1.753 of Secondary= 6.63 cfs @ 12.46 hrs, Volume= 0.318 of Routing by Stor-Ind method, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 755.84' @ 12.46 hrs Surf.Area= 0 sf Storage= 27,878 cf Plug-Flow detention time= 70.8 min calculated for 2.069 of(99% of inflow) Center-of-Mass det. time= 67.6 min ( 887.5 - 819.9 ) Volume Invert Avail.Storage Storage Description #1 753.75' 32,994 cf Custom Stage Data Listed below Elevation Cum.Store (feet) (cubic-feet) 753.75 0 754.00 217 754.50 3,537 755.00 9,958 755.30 14,849 755.50 18,780 755.75 24,894 756.00 32,994 Device Routing Invert Outlet Devices #1 Primary 753.75' 15.0" Round Culvert L= 102.0' RCP, mitered to conform to fill, Ke= 0.700 Inlet/ Outlet Invert= 753.75' /753.43' S= 0.0031 T Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.23 sf #2 Device 1 753.75' 0.8"Vert. Orifice/Grate X 2.00 C= 0.600 #3 Device 1 754.33' 15.0" x 27.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Secondary 755.45' 10.0' long x 70.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Primary OutFlow Max=5.26 cfs @ 12.46 hrs HW=755.84' (Free Discharge) L1=Culvert (Barrel Controls 5.26 cfs @ 4.28 fps) �__3=Orifi 2=Orifice/Grate (Passes < 0.05 cfs potential flow) ce/Grate (Passes < 16.65 cfs potential flow) Secondary OutFlow Max=6.61 cfs @ 12.46 hrs HW=755.84' (Free Discharge) L4=Broad-Crested Rectangular Weir (Weir Controls 6.61 cfs @ 1.69 fps) 100 year hydrocad developed pond 357817-10 WALN UPDATE Type 1124-hr Rainfall=7.22" Prepared by {enter your company name here} Printed 1/4/2018 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 5 Pond 4P: (new Pond) Hydrograph ....... r' In Inflow ,. {. ..................,23.71 ds ..... ... �.... .........� ..... ........... ...... .... Ufj1� outflow r'l ❑Primary ,X Inflow: Area all, . ISM Secondary 26 ' r' tIeV-7J58p 24-.`X Peak �.... x x x 22mf Storage : 27,87$.._c . =,x 20-- ,X ... 18-' r 16-.'xXx ; Cfs ..... ... .. ..... ,.... 14-m` r 0 12. .... x U- .......... x r 6. 2-'" 0... 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) DETENTION BASIN CALCULATIONS 11 (3S) 7S Origina Developed Site Offsite 11P (new Pond) OSu-bcat Reach on r Routing Diagram for 357817-10 WALN UPDATE Prepared by{enter your company name here}, Printed 12/19/2017 HydroCAD®10.00 s/n 00656 ©2011 HydroCAD Software Solutions LLC 100-Year First Developed Site 357817-10 WALN UPDATE Type 1124-hr Rainfall=7.22" Prepared by {enter your company name here} Printed 12/19/2017 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 2 Summary for Subcatchment 3S: Original Developed Site Runoff = 9.03 cfs @ 12.17 hrs, Volume= 0.752 af, Depth= 4.23" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr Rainfall=7.22" Area (ac) CN Description 2.130 74 >75% Grass cover, Good, HSG C 2.130 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.6 50 0.0100 0.11 Sheet Flow, Grass: Short n= 0.150 P2= 3.06" 16.2 500 0.0054 0.51 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 23.8 550 Total Subcatchment 3S: Original Developed Site Hyd rog raph 10 ❑Runoff .... .... 9.03 cfs , .... ......., 1 ,.... ......., 1 ,.... ,......., ,........ 9mx TYhc I1 24-hr 8 Rainfall=722". 7 Ru h off Area=2.1 30ac,,,...... ...... Runoff Voiarr�e^Q.752 air . 6-' Runoff Depth=4.23". . ° 5m Flo: *.Length=550LL '. . 4-: TG=23.8 : in 3. +CN-74 2- 0- 5 0.5 6 7 8 9 101112131415161718192021222324252627282930313233343536373839404142434445464748 Time (hours) 100-Year First Developed Site 357817-10 WALN UPDATE Type 1124-hr Rainfall=7.22" Prepared by {enter your company name here} Printed 12/19/2017 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment 7S: Offsite Runoff = 13.68 cfs @ 12.20 hrs, Volume= 1.238 af, Depth= 5.12" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr Rainfall=7.22" Area (ac) CN Description 1.400 91 Urban industrial, 72% imp, HSG C 1.500 74 >75% Grass cover, Good, HSG C 2.900 82 Weighted Average 1.892 65.24% Pervious Area 1.008 34.76% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.8 50 0.0200 0.14 Sheet Flow, Grass: Short n= 0.150 P2= 3.06" 21.0 710 0.0065 0.56 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 26.8 760 Total Subcatchment 7S: Offsite Hyd rog raph 15'm' ❑Runoff 13.68 cfs .. ..... .... ...., 14-m Type II 24-hrs 13-. 12- p.... ^.n Rq: n: APe1-2.900c'4C+...... 10mxm f Runoff VQlrame^1.238 of - 9:` jn ..... ........ , ..... , ......... 8: Runoff Depth=5.12'7. . 7: F.IO: W: : Len_gth=760'LL ... 6-.` Td-26.8 :'., i n........ 3- 2. 0_: 5 6 7 8 9 101112131415161718192021222324252627282930313233343536373839404142434445464748 Time (hours) 100-Year First Developed Site 357817-10 WALN UPDATE Type 1124-hr Rainfall=7.22" Prepared by {enter your company name here} Printed 12/19/2017 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 4 Summary for Pond 11 P: (new Pond) Inflow Area = 5.030 ac, 20.04% Impervious, Inflow Depth = 4.75" Inflow = 22.61 cfs @ 12.19 hrs, Volume= 1.990 of Outflow = 10.87 cfs @ 12.47 hrs, Volume= 1.990 af, Atten= 52%, Lag= 17.0 min Primary = 5.47 cfs @ 12.47 hrs, Volume= 1.748 of Secondary= 5.40 cfs @ 12.47 hrs, Volume= 0.241 of Routing by Stor-Ind method, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 755.79' @ 12.47 hrs Surf.Area= 0 sf Storage= 26,270 cf Plug-Flow detention time= 44.9 min calculated for 1.990 of(100% of inflow) Center-of-Mass det. time= 44.2 min ( 868.3 - 824.1 ) Volume Invert Avail.Storage Storage Description #1 753.71' 32,994 cf Custom Stage Data Listed below Elevation Cum.Store (feet) (cubic-feet) 753.71 0 754.00 217 754.50 3,537 755.00 9,958 755.30 14,849 755.50 18,780 755.75 24,894 756.00 32,994 Device Routing Invert Outlet Devices #1 Primary 753.71' 15.0" Round Culvert L= 82.0' RCP, mitered to conform to fill, Ke= 0.700 Inlet/ Outlet Invert= 753.71' /753.43' S= 0.0034 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.23 sf #2 Secondary 755.45' 10.0' long x 70.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Primary OutFlow Max=5.46 cfs @ 12.47 hrs HW=755.79' (Free Discharge) L1=Culvert (Barrel Controls 5.46 cfs @ 4.45 fps) Secondary OutFlow Max=5.37 cfs @ 12.47 hrs HW=755.79' (Free Discharge) L2=Broad-Crested Rectangular Weir (Weir Controls 5.37 cfs @ 1.57 fps) 100-Year First Developed Site 357817-10 WALN UPDATE Type 1124-hr Rainfall=7.22" Prepared by {enter your company name here} Printed 12/19/2017 HydroCAD® 10.00 s/n 00656 ©2011 HydroCAD Software Solutions LLC Page 5 Pond 11 P: (new Pond) Hydrograph ......, ........ ..... ......... .... Inflow In 22.61 ds CA outflow { Inflow Area-5.030 ai ❑Primary r' Secondary .... ..... 24 `X,X` Peaklev=75�7g' 22-: Storage20-°` =2627p _Cf . 18-': ff' 16-. X w 14. ' 10 87 cfs J x' 0 LL 12: (/ .. 10m`X x ... ...... .. ............... ..... ........., ...... .... 8-.`X 5.47 cfs 6.xX s ao crs 2":f 0_.: 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 !2"44 46 48 Time (hours) 7S gS Offsite PO4 osed Developed Site 11P (new Pond) �ca Reach on LInK Routing Diagram for 357817-10 WALN UPDATE Prepared by{enter your company name here}, Printed 12/19/2017 HydroCAD®10.00 s/n 00656 ©2011 HydroCAD Software Solutions LLC 100 Year Developed W/O Structure 357817-10 WALN UPDATE Type 1124-hr Rainfall=7.22" Prepared by {enter your company name here} Printed 12/19/2017 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 2 Summary for Subcatchment 7S: Offsite Runoff = 13.68 cfs @ 12.20 hrs, Volume= 1.238 af, Depth= 5.12" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr Rainfall=7.22" Area (ac) CN Description 1.400 91 Urban industrial, 72% imp, HSG C 1.500 74 >75% Grass cover, Good, HSG C 2.900 82 Weighted Average 1.892 65.24% Pervious Area 1.008 34.76% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.8 50 0.0200 0.14 Sheet Flow, Grass: Short n= 0.150 P2= 3.06" 21.0 710 0.0065 0.56 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 26.8 760 Total Subcatchment 7S: Offsite Hyd rog raph 15-'m' ❑Runoff 13.68 cfs .. ..... .... ...., 14- Type 11 24:::: -h r 13-. 12-':'` Ra:infa'l1=7.22"*...... Rw naff / Pe1-2.900 c'lC+...... 10mxm f Runoff VQlurne^1.238 0 - 9-: $: Runoff Depth=5.12'7. . 7: F.IOW.._Len_gth=760'LL ... 6-.` Td-26.8 :'., i n........ 5.'m` Q 4. ...... U1 *82........ ..... 3- 2-. 0-1 2- . " 5 6 7 8 9 10 1112 13 141516 17 1819 20 2122 23 24 25 26 27 28 29 30 3132 33 34 Time (hours) 100 Year Developed W/O Structure 357817-10 WALN UPDATE Type 1124-hr Rainfall=7.22" Prepared by {enter your company name here} Printed 12/19/2017 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment 9S: Proposed Developed Site Runoff = 10.15 cfs @ 12.17 hrs, Volume= 0.850 af, Depth= 4.79" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr Rainfall=7.22" Area (ac) CN Description 2.130 79 50-75% Grass cover, Fair, HSG C 2.130 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.6 50 0.0100 0.11 Sheet Flow, Grass: Short n= 0.150 P2= 3.06" 16.2 500 0.0054 0.51 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 23.8 550 Total Subcatchment 9S: Proposed Developed Site Hyd rog raph 11_.x ❑Runoff L... ; 10.15 cfs ..; L......; ..; ;.. 10 m Type 1124-h 9-. Ra: ,f $. Runoff Area=2.10 ac 7 x , Runoff Valurne^0.850 of . " Runoff Depth=479"; . 5m Flow...Length=550il: '........ ... 4- G= fYlin ...... ..... CN-79 3 . . .... 2- 0..:. 5 6 7 8 9 101112131415161718192021222324252627282930313233343536373839404142434445464748 Time (hours) 100 Year Developed W/O Structure 357817-10 WALN UPDATE Type 1124-hr Rainfall=7.22" Prepared by {enter your company name here} Printed 12/19/2017 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 4 Summary for Pond 11 P: (new Pond) Inflow Area = 5.030 ac, 20.04% Impervious, Inflow Depth = 4.98" Inflow = 23.71 cfs @ 12.18 hrs, Volume= 2.088 of Outflow = 11.71 cfs @ 12.46 hrs, Volume= 2.088 af, Atten= 51%, Lag= 16.5 min Primary = 5.54 cfs @ 12.46 hrs, Volume= 1.802 of Secondary= 6.17 cfs @ 12.46 hrs, Volume= 0.285 of Routing by Stor-Ind method, Time Span= 5.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 755.82' @ 12.46 hrs Surf.Area= 0 sf Storage= 27,292 cf Plug-Flow detention time= 44.4 min calculated for 2.088 of(100% of inflow) Center-of-Mass det. time= 43.8 min ( 863.7 - 819.9 ) Volume Invert Avail.Storage Storage Description #1 753.71' 32,994 cf Custom Stage Data Listed below Elevation Cum.Store (feet) (cubic-feet) 753.71 0 754.00 217 754.50 3,537 755.00 9,958 755.30 14,849 755.50 18,780 755.75 24,894 756.00 32,994 Device Routing Invert Outlet Devices #1 Primary 753.71' 15.0" Round Culvert L= 82.0' RCP, mitered to conform to fill, Ke= 0.700 Inlet/ Outlet Invert= 753.71' /753.43' S= 0.0034 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.23 sf #2 Secondary 755.45' 10.0' long x 70.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Primary OutFlow Max=5.54 cfs @ 12.46 hrs HW=755.82' (Free Discharge) L1=Culvert (Barrel Controls 5.54 cfs @ 4.51 fps) Secondary OutFlow Max=6.15 cfs @ 12.46 hrs HW=755.82' (Free Discharge) L2=Broad-Crested Rectangular Weir (Weir Controls 6.15 cfs @ 1.65 fps) 100 Year Developed W/O Structure 357817-10 WALN UPDATE Type 1124-hr Rainfall=7.22" Prepared by {enter your company name here} Printed 12/19/2017 HydroCAD® 10.00 s/n 00656 @2011 HydroCAD Software Solutions LLC Page 5 Pond 11 P: (new Pond) Hydrograph ....... r' In Inflow ,. {. ..................,23.71 ds ..... ... �.... .........� ..... ........... ...... .... Ufj1� outflow r'l ❑Primary ,x Inflow: Area all, . ISM Secondary 26 _ r' t p 24-mxx xxx„ Peak Elev-75.82 x ..... . mx xxx f, 22Storage : 2T.292.._c . 20-- xx ,x ... 18- r 16-.'x,=' 11 71 f .... ... ..... ... ..... ...., .... w v 14 x f o ° 92- � . 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