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2342,2364,2386 Clark St-20181128-Valley Ridge Addition�r..y 0 .�8 � -o sRy 'K, w a) U O `0 a) :3.c o E (!) 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W ° I� O : .3 CD O. Zr' (gyp a ~ • CCD '* cu .�' CD .+. CD Q. c -o ¢+ CD ' o CD �•�° R� C� �. Pa a CD as Q o � ° CD CD n CCD �C '.°3 CD C. O � a' ! �' V .� °p�c0D O. CD �. �• fD r Z ~. o .� o "CD oE�3 -. C � o ... a. � r* CD y , CD CD P CD CD CD cDY' ° �' Z CD C4 b7 cr0 CD CD CD aCD =C o ~. CL Ib -a 1 o o a arc rCD CD CD o o o CD ;D CND a �' F~ CD CD CD H � Oar p'O , CD m O G ° N O ` � Ul co o O toz o o ci9 u z d ~ ~� CD CD �' U' � w °� o yr •vii O O' C:) ms cc W CD p oQ w oo -r m 3 r,y 'r CD O i CD p P. h CD rD LnLn Allen Schoemaker From: dan@civsolutions.com Sent: Wednesday, November 28, 2018 2:36 PM To: Allen Schoemaker Subject: RE: Valley Ridge Sounds good Al. That's kind of what I figured would have to happen. Daniel E. Norman, P.E. Civil Solutions, LLC 16439 Briar St. Omaha, NE 68136 (402)895-5633 -------Original Message ------- From: Allen Schoemaker <ars@blairnebraska.org> To: dan@civsolutions.com <dan@civsolutions.com> Cc: Phil Green <pcgreen@blairnebraska.org>, Shelly Jones <shellyj@blairnebraska.org>, Brenda Wheeler <brwheeler@blairnebraska.org> Subject: RE: Valley Ridge Sent: Nov 28'18 13:27 Dan, I am fine with accepting what you have submitted todate as a preliminary report that will need to be finalized once each lot is being constructed on. At that time there will need to be a follow up report from you that will specifically identify the amount of additional storm water and a plan to detain it on site. The construction of the detention facilities would then be constructed at the same time the lot is being developed. Phil, Shelly & Brenda —these lots will need to be flagged for the future that when a house plan is submitted for each lot the property owner will need to have an individual storm water plan for their lot. Al Schoemaker, PWLF Director of Public Works City of Blair 402-426-4191 ARS@blairnebraska.org Allen Schoemaker To: dan@civsolutions.com Cc: Phil Green; Shelly Jones; Brenda Wheeler Subject: RE: Valley Ridge Dan, I am fine with accepting what you have submitted todate as a preliminary report that will need to be finalized once each lot is being constructed on. At that time there will need to be a follow up report from you that will specifically identify the amount of additional storm water and a plan to detain it on site. The construction of the detention facilities would then be constructed at the same time the lot is being developed. Phil, Shelly & Brenda — these lots will need to be flagged for the future that when a house plan is submitted for each lot the property owner will need to have an individual storm water plan for their lot. PWLF Director of Public Works City of Blair 402.426.4191 ARS@blairnebraska.or From: dan@civsolutions.com <dan@civsolutions.com> Sent: Wednesday, November 28, 2018 12:15 PM To: Allen Schoemaker <ars@blairnebraska.org> Subject: Re: Valley Ridge Al, The problem right now is that I do not know the exact size of each of those buildings. The only thing I can do now is to estimate the size and location. When the plans for the actual buildings are finalized, I can develop an actual plan for detention. That is when the actual survey is going to be needed. I explained this to the owner, and he is taking care of that for Lot 3 right now. We know the general direction of flow, and I know the existing runoff amounts from those sites. The final runoff will be detemined from the size of the buildings and how much concrete they plan to use for the drives. That is unknown right now. Can this plan be submitted as the Stormwater Plan for the sites and when they get the actual building permit, we can submit the locations and depths for detention? Daniel E. Norman, P.E. Civil Solutions, LLC 16439 Briar St. Omaha, NE 68136 (402)895-5633 -------Original Message------- From: Allen Schoemaker <ars@blairnebraska.org> To: dan@civsolutions.com <dan@civsolutions.com> PROPOSED SITE CONDITIONS Total area = 3.80 acres Paved Roofs/Drives 0.25 acres CN = 98 Open Space; grass cover 75% 1.50 acres CN = 61 Woods/Grass Combination 2.05 acres CN = 58 Weighted Curve Number = 62 Q100 =12.00 cfs The required storage area is 600 cubic feet. This can be accomplished by constructing a berm along the southeast property line. The exact height and location of the berm will need to be determined after a topographic survey is completed on the lot. The survey will identify appropriate locations for detention storage. LOT 4 EXISTING SITE CONDITIONS From the Natural Resources Conservation Service, it was determined that the soils in this area are classified as Pohocco-Monona complex. The Hydrologic Soil Group for this soil is B. Drainage on the site is generally from the west to the east. Storm runoff from the entire site will be used to design the required storage. Total area = 0.76 acres Woods/Grass Combination Q100 = 2.32 cfs PROPOSED SITE CONDITIONS Total area = 0.76 acres Paved Roofs/Drives Open Space; grass cover 75% Woods/Grass Combination Q100 = 4.07 cfs CN=58 0.25 acres CN = 98 0.37 acres CN = 61 0.14 acres CN = 58 Weighted Curve Number = 73 www.civsolutions.com The required storage area is 1,045 cubic feet. This can be accomplished by constructing a combination of berms and detention storage. The exact height and location of these structures will need to be determined after a topographic survey is completed on the lot. The survey will identify appropriate locations for detention storage. LOT 5 EXISTING SITE CONDITIONS From the Natural Resources Conservation Service, it was determined that the soils in this area are classified as Judson silty clay loam. The Hydrologic Soil Group for this soil is C. Drainage on the site is generally from the west to the east. Storm runoff from the entire site will be used to design the required storage. Total area = 0.76 acres Woods/Grass Combination Q100 = 3.74 cfs PROPOSED SITE CONDITIONS Total area = 0.76 acres Paved Roofs/Drives Open Space; grass cover 75% Woods/Grass Combination Q100 = 4.79 cfs CN = 72 0.25 acres CN = 98 0.37 acres CN = 61 0.14 acres CN = 58 Weighted Curve Number = 82 The required storage area is 505 cubic feet. This can be accomplished by constructing a combination of berms and detention storage. The exact height and location of these structures will need to be determined after a topographic survey is completed on the lot. The survey will identify appropriate locations for detention storage. www.civsolutions.com ATTACHMENTS No. 1— Lots 3,4, and 5 Drainage Plan No. 2 — Soil Map and Data No. 3 — Lot 3 Drainage Analysis for Existing Site Conditions (7 pages) No. 4 — Lot 3 Drainage Analysis for Proposed Site Conditions (7 pages) No. 5 — Lot 3 Storage Calculations (3 Pages) No. 6 — Lot 4 Drainage Analysis for Existing Site Conditions (7 pages) No. 7 — Lot 4 Drainage Analysis for Proposed Site Conditions (7 pages) No. 8 — Lot 4 Storage Calculations (3 Pages) No. 9 — Lot 5 Drainage Analysis for Existing Site Conditions (7 pages) No. 10 — Lot 5 Drainage Analysis for Proposed Site Conditions (7 pages) No. 11— Lot 5 Storage Calculations (3 Pages) 11/19/2018 www.civsolutions.com A O m O � r � � o �i Z Zags =pyos �On y ii 9y 'O BOO pZ i. 7 Fy As°I yy° K K c 4 ffiFF ° 3a�F m 55 �i U7 m iii55s Yn s z A a z A c� t� z W f�� 110 11 111 p � m U PH � o c � a n ^ S "AA S cmi 9 T 4g 42 4g 4 4g g Ln 0m ;3 8 n Rm G C7 ' D r m v �C D z m z Z O 11/19/2018 VALLEY RIDGE ADDITION O1^c auu WASHINGTON COUNTY, NEc CMI 1 of 1 Rxo. LOTS 3A &5 DRAINAGE PLAN �w; p' solud0O8'. ciuw. '8'SrW 9 A A y� K k K z 2 96° 8' ST W 771 O = ll d p OrrH �o r CD O tv CO CD C 0 CD O � cn c r CD 2 �7 W 07 96° &46"W I 0 4601990 4602030 46MM 4602110 4602150 4602190 4602130 4607270 4602310 li m Z N N G N N N N N N ;I1 m n n m 0 N G ON m g o o e > m ? o m o D N � O m m d a � ai Z1 � m m Z S O O C m y 110 N N O N m 6 m pN m O m i N 0 N m >-2 v r n N 3 T m O. S38 S <T C O. �m9.3 ovm 03 0c m9 m�J�y amg cm oQ c - rnoa 2 mn. ma`�Op ma. -o, mm amv m 0c m„m� y.c �c� 3 mm 3.c � am• m y �m a" c d� m 'm co) m� ^' I o ommV 3cZ ym QJaS m v �� �y JmO SO'Dmy Am m m mm _ 'om0 7 d m Qm m 0- us- na' m p 10 y c o' I. 3 Q m S y IS Q O d m O n N O I m,g3 . mo 3 n a.' m c J ymn� m y yn iEr omi o• m m a= C m �a c mm�$ >• p1 N.� 0 m 'mNmy m o 3 0 a D m am 'm v nc3� m �' �v Z �v2 so � m W d m ^ O O' m o m 'o m . n °1 ch O O m 3 m CY m m m m w m O D r m 0 m z v a z O O z m m Soil Map—Washington County, Nebraska Map Unit Legend USDA Natural Resources Web Soil Survey 11/17/2018 Conservation Service National Cooperative Soil Survey Page 3 of 3 Map Unit Symbol Map Unit Name Acres In AOI Percent of AOI 7234 Judson silty clay loam, 2 to 6 percent slopes 1.2 13.7% 8008 Ida silt loam, 17 to 30 percent slopes, eroded 4.9 56.6% 8076 Monona silt loam, 1 to 6 percent slopes, eroded 0.0 0.2% 8142 Pohocco-Monona complex, 11 to 17 percent slopes, eroded 2.6 29.6% Totals for Area of Interest 8.7 100.0% USDA Natural Resources Web Soil Survey 11/17/2018 Conservation Service National Cooperative Soil Survey Page 3 of 3 Map Unit Description: Judson silty clay loam, 2 to 6 percent slopes ---Washington County, Nebraska Washington County, Nebraska 7234—Judson silty clay loam, 2 to 6 percent slopes Map Unit Setting National map unit symbol: 2sy70 Elevation: 960 to 1,350 feet Mean annual precipitation: 30 to 32 inches Mean annual air temperature: 50 to 51 degrees F Frost -free period. 160 to 170 days Farmland classification: All areas are prime farmland Map Unit Composition Judson and similar soils: 80 percent Minor components: 20 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Judson Setting Landform: Alluvial fans Landform position (two-dimensional): Footslope Landform position (three-dimensional): Base slope Down-slope shape: Concave Across -slope shape: Linear Parent material: Silty colluvium Typical profile Ap - 0 to 9 inches: silty clay loam A - 9 to 22 inches: silty clay loam AB - 22 to 28 inches: silty clay loam Bt - 28 to 35 inches: silty clay loam BC - 35 to 52 inches: silty clay loam C - 52 to 79 inches: silty clay loam Properties and qualities Slope: 2 to 6 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0. 14 to 1.42 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 10 percent Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: High (about 11.6 inches) USDA Natural Resources Web Soil Survey 11/17/2018 Conservation Service National Cooperative Soil Survey Page 1 of 2 Map Unit Description: Judson silty clay loam, 2 to 6 percent slopes ---Washington County, Nebraska Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 2e Hydrologic Soil Group: C Ecological site: Loamy Footslope Savanna (R107BY008MO) Hydric soil rating: No Minor Components Kennebec, occasionally flooded Percent of map unit: 14 percent Landform: Flood plains Landform position (two-dimensional): Toeslope Landform position (three-dimensional): Talf Down-slope shape: Linear Across -slope shape: Linear Ecological site: Loamy Floodplain Prairie (R107BY0251A) Hydric soil rating: No Ackmore, occasionally flooded Percent of map unit: 4 percent Landform: Flood plains Landform position (three-dimensional): Talf Down-slope shape: Linear Across -slope shape: Linear Ecological site: Wet Floodplain Prairie (R1 07BY01 9MO) Hydric soil rating: No Kezan, occasionally flooded Percent of map unit: 2 percent Landform: Flood plains Landform position (two-dimensional): Toeslope Landform position (three-dimensional): Talf Down-slope shape: Linear Across -slope shape: Linear Ecological site: Wet Floodplain Prairie (RI 07BY019MO) Hydric soil rating: Yes Data Source Information Soil Survey Area: Washington County, Nebraska Survey Area Data: Version 17, Sep 12, 2018 USDA Natural Resources Web Soil Survey 11/17/2018 Conservation Service National Cooperative Soil Survey Page 2 of 2 Map Unit Description: Ida silt loam, 17 to 30 percent slopes, eroded --Washington County, Nebraska Washington County, Nebraska 8008—Ida silt loam, 17 to 30 percent slopes, eroded Map Unit Setting National map unit symbol. 2sgr3 Elevation: 960 to 1,470 feet Mean annual precipitation: 28 to 34 inches Mean annual air temperature: 49 to 53 degrees F Frost -free period. 155 to 175 days Farmland classification: Not prime farmland Map Unit Composition Ida, eroded, and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Ida, Eroded Setting Landform: Loess hills Landform position (two-dimensional): Shoulder, backslope Landform position (three-dimensional): Side slope Down-slope shape: Convex Across -slope shape: Convex Parent material. Calcareous loess Typical profile Ap - 0 to 6 inches: silt loam C - 6 to 79 inches: silt loam Properties and qualities Slope: 17 to 30 percent Depth to restrictive feature: More than 80 inches Natural drainage class. Well drained Runoff class: High Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0. 14 to 1.42 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 14 percent Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: Very high (about 12.7 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6e Hydrologic Soil Group: B usDA Natural Resources Web Soil Survey 11/17/2018 it Conservation Service National Cooperative Soil Survey Page 1 of 2 Map Unit Description: Ida silt loam, 17 to 30 percent slopes, eroded --Washington County, Nebraska Ecological site: Calcareous Loess Exposed Backslope Prairie (R107BY006MO), Calcareous Loess Protected Backslope Savanna (R107BY013MO) Hydric soil rating: No Minor Components Monona, eroded Percent of map unit: 10 percent Landform: Loess hills Landform position (two-dimensional): Shoulder, backslope Landform position (three-dimensional): Side slope Down-slope shape: Convex Across -slope shape: Convex Ecological site: Deep Loess Exposed Backslope Savanna (R107BY003MO) Hydric soil rating: No Steinauer, eroded Percent of map unit: 5 percent Landform: Loess hills Landform position (two-dimensional): Shoulder, backslope Landform position (three-dimensional): Side slope Down-slope shape: Convex Across -slope shape: Convex Ecological site: Calcareous Till Upland Prairie (R107BY0271A) Hydric soil rating: No Data Source Information Soil Survey Area: Washington County, Nebraska Survey Area Data: Version 17, Sep 12, 2018 USDA Natural Resources Web Soil Survey 11/17/2018 Conservation Service National Cooperative Soil Survey Page 2 of 2 Map Unit Description: Pohocco-Monona complex, 11 to 17 percent slopes, eroded -- Washington County, Nebraska Washington County, Nebraska 8142—Pohocco-Monona complex, 11 to 17 percent slopes, eroded Map Unit Setting National map unit symbol. f8k4 Elevation: 1,000 to 1,500 feet Mean annual precipitation: 28 to 30 inches Mean annual air temperature: 50 to 54 degrees F Frost -free period. 150 to 170 days Farmland classification: Not prime farmland Map Unit Composition Pohocco, eroded, and similar soils: 57 percent Monona, eroded, and similar soils: 40 percent Minor components: 3 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Pohocco, Eroded Setting Landform: Loess hills Landform position (two-dimensional): Shoulder, backslope Landform position (three-dimensional): Head slope, nose slope, side slope Down-slope shape: Convex Across -slope shape: Convex Parent material. Loess Typical profile Ap - 0 to 6 inches: silty clay loam Bw - 6 to 15 inches: silt loam Bk -15 to 28 inches: silt loam C - 28 to 80 inches: silt loam Properties and qualities Slope: 11 to 17 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: High Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 10 percent Available water storage in profile: High (about 11.6 inches) Interpretive groups Land capability classification (irrigated): None specified USDA Natural Resources Web Soil Survey 11/17/2018 r Conservation Service National Cooperative Soil Survey Page 1 of 3 Map Unit Description: Pohocco-Monona complex, 11 to 17 percent slopes, eroded -- Washington County, Nebraska Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Ecological site: Silty - Veg. zone 4 (R107XY075NE), Calcareous Loess Protected Backslope Forest (F107BY010MO), Calcareous Loess Exposed Backslope Woodland (F107BY011 MO) Forage suitability group: Loam(G107BY100NE) Hydric soil rating: No Description of Monona, Eroded Setting Landform: Loess hills Landform position (two-dimensional): Landform position (three-dimensional). head slope Down-slope shape: Convex Across -slope shape: Convex Parent material. Fine -silty loess Typical profile Ap - 0 to 7 inches: silt loam A - 7 to 15 inches: silt loam Bw - 15 to 30 inches: silt loam C - 30 to 60 inches: silt loam Backslope, shoulder Side slope, nose slope, Properties and qualities Slope: 11 to 17 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 25 percent Available water storage in profile: High (about 12.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Ecological site: Silty - Veg. zone 4 (R107XY075NE), Deep Loess Exposed Backslope Savanna (R107BY003MO) Forage suitability group: Not Suited (G107BY000NE) Hydric soil rating: No Minor Components Ida, eroded Percent of map unit. 3 percent Landform: Loess hills Landform position (two-dimensional): Backslope USD Natural Resources Web Soil Survey 11/17/2018 Conservation Service National Cooperative Soil Survey Page 2 of 3 Map Unit Description: Pohocco-Monona complex, 11 to 17 percent slopes, eroded -- Washington County, Nebraska Landform position (three-dimensional): Head slope, side slope, nose slope Down-slope shape: Convex Across -slope shape: Convex Ecological site: Limy Upland (R102CY059NE), Calcareous Loess Upland Prairie (Rl07BY012MO) Hydric soil rating: No Data Source Information Soil Survey Area: Washington County, Nebraska Survey Area Data: Version 17, Sep 12, 2018 usDA Natural Resources Web Soil Survey 11/17/2018 ii Conservation Service National Cooperative Soil Survey Page 3 of 3 H ro 3 O N rrt 3 r- 0 0 m m O K rrc 0 z no Ni mlZ I N I H N I O I-` I tm 0 ca m lv a P. O rr G K to F- 0 w 0' O (D m z rtHu-K 0tt ° rt P- o •• r rt N fD •• P) m o t. w w n5 b'rt�p P. r• a w m P• w x m Hrra k w o W a EQ M o rr k r r- m rt, W o' w zw m rt z 0 0 ° x rn m m K k C P) r r m r - W t ] � m ID P- rt Wca R a a N- p rr N- M- rt o m o 0 rt Kk\ (D r r w m P. m to \ M O N k o F.. co m m rt p k Ut Lrl I I p I H a u+ m cn rt n w q n m rr ca it H a a a rr o w a rr (D w En 1 O I K ro rr H- 0 0 N 0 M w I W m a 1 7tG " K 0 Fr-• Doi O ct I r d a I m "m' W m rt O I H C I rt rt•• w I O rC � x 0 1 x C d I w n H IP. koro i a N I N a' � I r•o d M K I K rt I A w 1 �< m a (D W 1 k O K rt Cn I N- a CL 0 N I C7 I M rr Ul w w n 1 K r O I r C I I I SV I c rr I N ` I rCi ko i 0 ro Ln I "I4 (D K z i w x I o LL co � �• I I I ON i r I Y• O Ln 1 00 cn r1 I K I I I I I 0 m m O K rrc 0 z no Ni mlZ I N I H N I O I-` I tm 0 ca m lv a P. O rr G K to F- 0 w 0' O (D m z rtHu-K 0tt ° rt P- o •• r rt N fD •• P) m o t. w w n5 b'rt�p P. r• a w m P• w x m Hrra k w o W a EQ M o rr k r r- m rt, W o' w zw m rt z 0 0 ° x rn m m K k C P) r r m r - W t ] � m ID P- rt Wca R a a N- p rr N- M- rt o m o 0 rt Kk\ (D r r w m P. m to \ M O N k o F.. co m m rt p k Ut Lrl I I p I H a u+ m cn rt n w q n m rr ca it H a a a rr o w a rr (D w En 1 O I K ro rr H- 0 0 Dan Valley Ridge Addition Lot 3 Existing Washington County, Nebraska Storm Data Rainfall Depth by Rainfall Return Period 2 -Yr 5 -Yr 10 -Yr 25 -Yr 50 -Yr 100 -Yr 1 -Yr (in) (in) (in) (in) (in) (in) (in) -------------------------------------------------------------------------------- 3.0 3.87 4.6 5.25 5.95 6.55 2.42 Storm Data Source: Washington County, NE (NRCS) Rainfall Distribution Type: Type II Dimensionless Unit Hydrograph: <standard> WinTR-55, Version 1.00.10 Page 1 11/18/2018 11:22:03 PM r H FA r 0 N O co o o CD N O O r 0 0 I r O 1 n o 6 1 m rt N I M E a m E N C (D W N fD h+ n 0 o 0 o m W p rt LC m w xf R. 0 O Y• C Lam] R. ro cl x w m ct < �- m w - a PV K >1 H z ti 0.. U CY ct F. n r- SD o N O X SD C: n wC i a0 o a r n i tr ywy It H Cl N ?� m i 1.,0m I m xa I H o o CD N O O r 0 0 I r O 1 n o 6 1 m rt N I M E a m E N C (D W N fD h+ n 0 o 0 o m W p rt LC m w xf R. 0 O Y• C Lam] R. ro cl x w m ct < �- m w - a PV K >1 H z ti 0.. U CY ct F. n r- SD o N O X SD Dan Valley Ridge Addition Lot 3 Existing Washington County, Nebraska Hydrograph Peak/Peak Time Table Sub-Area Peak Flow and Peak Time (hr) by Rainfall Return Period or Reach 2-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr Identifier (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (hr) (hr) (hr) (hr) (hr) (hr) ---------------------------------------------------------------------------------- SUBAREAS A3 0.71 2.34 4.13 5.96 8.10 10.05 12.09 12.07 12.06 12.05 12.04 12.04 REACHES OUTLET 0.71 2.34 4.13 5.96 8.10 10.05 WinTR-55, Version 1.00.10 Page 1 11/18/2018 11:22:03 PM Dan Valley Ridge Addition Lot 3 Existing Washington County, Nebraska Sub -Area Summary Table Sub -Area Drainage Time of Curve Receiving Identifier Area Concentration Number Reach (ac) (hr) ------------------------------------------------------ A3 3.80 0.221 58 Outlet Total Area: 3.80 (ac) Sub -Area Description WinTR-55, Version 1.00.10 Page 1 11/18/2018 11:22:03 PM Dan Valley Ridge Addition Lot 3 Existing Washington County, Nebraska Sub -Area Time of Concentration Details Sub -Area Flow Mannings's End Wetted Travel Identifier/ Length Slope n Area Perimeter Velocity Time (ft) (ft/ft) (sq ft) (ft) (ft/sec) (hr) -------------------------------------------------------------------------------- A3 SHEET 71 0.0150 0.240 0.210 SHALLOW 242 0.1488 0.050 0.011 Time of Concentration .221 WinTR-55, Version 1.00.10 Page 1 11/18/2018 11:22:03 PM Dan Sub -Area Identifier A3 Valley Ridge Addition Lot 3 Existing Washington County, Nebraska Sub -Area Land Use and Curve Number Details Hydrologic Sub -Area Land Use Soil Area Group (ac) --------------------------------------------------------------- Woods - grass combination (good) B 3.8 Total Area / Weighted Curve Number 3.8 Curve Number 58 58 WinTR-55, Version 1.00.10 Page 1 11/18/2018 11:22:03 PM ro a R m r d w car A H U1 a o rw (da m r• N N 0 m rt O WGm w crrt•• W N- 'C o p a. H o �C w �u K m G• � Mk w a m x p W a�a ras ~ rt Ln v p N cn n O G r rt z Ln Ln z n y U1 F'• I p H z a 0 M a r r ry ccr I to L< o K ID B H- N N• t7 in " rt -- K a w K r r z CD rt G L k m K K 0 >L N C O H O G rt r m cr ry K CD m a Pi t7 m a :r fi a I I roncmmroa H- O rt C K N r0a2YOm mCrtHu.K ID �C c~+ p • • c r w m 0 w w b'c1•�`,1 C d ra wC I-• W x ro r rt w K xl m0 ro a 1- o W 0 m m rt a� 0 it o a m c~+ i r• z 0 tiO x ((D (D K C a r r m z w n0a CD m P. rt r N (D w cr H. O m O O 0 N ch K to \ m r r-• w rA H. co ro tr N 10 O O M CD L1. E Ln N E I H N I CCD ul � n W C M H W K w � rt rt P. 0 w rt C7 w w rt t7 ID w n I 'd rt O a Dan Valley Ridge Addition Lot 3 Proposed Washington County, Nebraska Storm Data Rainfall Depth by Rainfall Return Period 2 -Yr 5 -Yr 10 -Yr 25 -Yr 50 -Yr 100 -Yr 1 -Yr (in) (in) (in) (in) (in) (in) (in) -------------------------------------------------------------------------------- 3.0 3.87 4.6 5.25 5.95 6.55 2.42 Storm Data Source: Washington County, NE (NRCS) Rainfall Distribution Type: Type II Dimensionless Unit Hydrograph: <standard> WinTR-55, Version 1.00.10 Page 1 11/18/2018 11:25:12 PM F- ro 3 H N 0 0 w w .C. dl� .a a �o ID r 0 0 w K E a m E � C N (D c r 0 0 (D K O O N N w N 0 w W H. PL o aroa ro 7KW m c+ o m P) k Id0 PV - o vy N a H (D N a a v ¢ (* N K F'• (D a O N J x ID wcia0m a a M 7 r n �i�Ktr• HM [�=1 I Fes'- co y I W O (D I (D �r a I K H N 0 0 w w .C. dl� .a a �o ID r 0 0 w K E a m E � C N (D c r 0 0 (D K O O N N w N 0 w W H. PL o aroa ro 7KW m c+ o m P) k Id0 PV - o vy N a H (D N a a v ¢ (* N K F'• (D a O N J x ID Dan Valley Ridge Addition Lot 3 Proposed Washington County, Nebraska Hydrograph Peak/Peak Time Table Sub-Area Peak Flow and Peak Time (hr) by Rainfall Return Period or Reach 2-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr Identifier (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (hr) (hr) (hr) (hr) (hr) (hr) ---------------------------------------------------------------------------------- SUBAREAS A3 1.40 3.44 5.51 7.54 9.89 12.00 12.08 12.05 12.05 12.04 12.04 12.04 REACHES OUTLET 1.40 3.44 5.51 7.54 9.89 12.00 WinTR-55, Version 1.00.10 Page 1 11/18/2018 11:25:12 PM Dan Valley Ridge Addition Lot 3 Proposed Washington County, Nebraska Sub -Area Summary Table Sub -Area Drainage Time of Curve Receiving Identifier Area Concentration Number Reach (ac) (hr) ------------------------------------------------------ A3 3.80 0.221 62 Outlet Total Area: 3.80 (ac) Sub -Area Description WinTR-55, Version 1.00.10 Page 1 11/18/2018 11:25:12 PM Dan Valley Ridge Addition Lot 3 Proposed Washington County, Nebraska Sub -Area Time of Concentration Details Sub -Area Flow Mannings's Identifier/ Length Slope n ----------------------------------------- (ft) (ft/ft) A3 SHEET 71 0.0150 0.240 SHALLOW 242 0.1488 0.050 End Wetted Area Perimeter (sq ft) (ft) ------------------ Travel Velocity Time (ft/sec) (hr) ---------------- 0.210 0.011 Time of Concentration .221 WinTR-55, Version 1.00.10 Page 1 11/18/2018 11:25:12 PM Dan Valley Ridge Addition Lot 3 Proposed Washington County, Nebraska Sub -Area Land Use and Curve Number Details Sub -Area Hydrologic Sub -Area Identifier Land Use Soil Area Group (ac) ------------------------------------------------------------------------- A3 Open space; grass cover > 75% (good) B 1.5 Paved parking lots, roofs, driveways B .25 Woods - grass combination (good) B 2.05 Total Area / Weighted Curve Number 3.8 Curve Number 61 98 58 62 WinTR-55, Version 1.00.10 Page 1 11/18/2018 11:25:12 PM ATTACHMENT NO. 5 Ytg ue 6-1 pproxi=-ate clefentiOn tkabin r011t4ng for rainfall I.Njw-s I, Ik Il, and M LOT 3 - STORAGE CALCULATIONS (3 PAGES) DETENTION BASIN SIZE p .5 a� C a 65, cc 0.162 .1 1 .2 -3 .4 .5 .6 .7 Is 0.84 Pear outflow discharge qo Peak inflow discharge qi i -°T (_ 1 Second Ed.,. June 1986) Figure 2-1 Solution of runoff equation. 8 7 6 iii 2.15 2 1 a LOT 3 - STORAGE CALCULATIONS DIRECT RUNOFF - EXISTING Curves on this sheet are for the --- - - - - - -- -- -- -- ---- case la = 0.2S, so that Q — (P -0.2S)2 P+0.8S 1 2 3 4 5 6 6.55 7 Rainfall (P), inches 8 9 10 11 12 Figure 2-1 Solution of runoff equation. LOT 3 - STORAGE CALCULATIONS DIRECT RUNOFF - PROPOSED 8 I I I I I I - _ 7 Curves on this sheet are for the I i case la = 0.2S, so that Q - (P -0.2S)2 6- � gyp �O _Cn (D 5- c 0 �O `. O m3 - - ---- -- - - - -- - -- — -- -- -- - 5 FF- 2.42 - 2---- -- --------- ----- -- --- - - -p0 --I I I 0 0 1 2 3 4 5 6 6.55 7 8 9 10 11 12 Rainfall (P), inches F-- °art wo O C �r r CD rt P. 0 rt C H m rC a U'0 (D (D •J ft H �- H SD K [ ID ~t f0] •• D •• rr P) m 0 m w H- F'- a .p 0 C C m C H• (q x• t 1 r 0 k H. m� H. H. O rtw 0 0 a ct Fl. �� a a z 0 r- C n x m m H c w r r CD w m (D w ID ID rt (D ft w H. rr O N C .. r >ttr 0-r H La c \ (D r N W \ x o r- r N O ct C W I I p I H� N I (D Ul m c>, 0 K � r- H rH fi w H w 0 ct rt 0 I.Ij p rt d a rr d a m m I res I w ro rt P- 0 m a wro o I --n O rw I p rt I I CDP- W N H C 1 CYn wI-.c H- C fD I W I ctrt•• o I p k HH O lC I M H ((DD I N •• r V I ..r I 10 N I C1 1 K ro I I H rr I a m x � 1 0 ti N N- H rt U1 I .-. N d v n m i �I a t -h rt Ln I k w w n I H r 0 I r C I I 7 I I (D K i ct I rpt Ln i wo m ni K i H w z d I O n I a W I I I W O (n I C O (n I I I K I H I I I I I N I r �7 I K O C �r r CD rt P. 0 rt C H m rC a U'0 (D (D •J ft H �- H SD K [ ID ~t f0] •• D •• rr P) m 0 m w H- F'- a .p 0 C C m C H• (q x• t 1 r 0 k H. m� H. H. O rtw 0 0 a ct Fl. �� a a z 0 r- C n x m m H c w r r CD w m (D w ID ID rt (D ft w H. rr O N C .. r >ttr 0-r H La c \ (D r N W \ x o r- r N O ct C W I I p I H� N I (D Ul m c>, 0 K � r- H rH fi w H w 0 ct rt 0 I.Ij p rt d a rr d a m m I res I w ro rt P- 0 Dan Valley Ridge Addition Lot 4 Existing Washington County, Nebraska Storm Data Rainfall Depth by Rainfall Return Period 2 -Yr 5 -Yr 10 -Yr 25 -Yr 50 -Yr 100 -Yr 1 -Yr (in) (in) (in) (in) (in) (in) (in) ----------------------------------------------------------------------------- 3.0 3.87 4.6 5.25 5.95 6.55 2.42 Storm Data Source: Washington County, NE (NRCS) Rainfall Distribution Type: Type II Dimensionless Unit Hydrograph: <standard> WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:54:48 PM to w (D m r Fl r \ co O N co O °c �c m 1 a0 y aSD 3 h 0 0 chi i m Hw�y1 fn ✓y I M w (D :7' 0) n I I O O I I f1 N N N N h< O O hY 1 ro a I w 1 x ro E O O I M 1 O N N N I to K E :r OD co v� a a i tr H 0 ar h (D I a N b ct "C I �rN• ;r' O O 1 0 O p N l7 ac w I M I M a 0 N - to v v a I hY r ro C [ ] p. C (D I r N CT W N I w N I ',U x - ct ,b OH w (D L4 - 1 0 N M V tr ct I M I 'J I- hi P. (D w O � � 1�rsro rA d I (D X I hS a I w I 0 I a I .•. N O MI- I I rn m I " h5 I r N N I Cl O I M I W W I N K I I I I I Dan Valley Ridge Addition Lot 4 Existing Washington County, Nebraska Hydrograph Peak/Peak Time Table Sub -Area Peak Flow and Peak Time (hr) by Rainfall Return Period or Reach 2 -Yr 5 -Yr 10 -Yr 25 -Yr 50 -Yr 100 -Yr Identifier (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) ---------------------------------------------------------------------- (hr) (hr) (hr) (hr) (hr) (hr) SUBAREAS A4 0.20 0.58 0.97 1.37 1.86 2.32 12.03 12.02 12.01 11.97 11.96 11.95 REACHES OUTLET 0.20 0.58 0.97 1.37 1.86 2.32 WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:54:48 PM Dan Valley Ridge Addition Lot 4 Existing Washington County, Nebraska Sub -Area Summary Table Sub -Area Drainage Time of Curve Receiving Identifier Area Concentration Number Reach (ac) (hr) ------------------------------------------------------ A4 .76 0.114 58 Outlet Total Area: .76 (ac) Sub -Area Description WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:54:48 PM Dan Valley Ridge Addition Lot 4 Existing Washington County, Nebraska Sub -Area Time of Concentration Details Sub -Area Flow Mannings's End Wetted Travel Identifier/ Length Slope n Area Perimeter Velocity Time -------------------------------------------------------------------------------- (ft) (ft/ft) (sq ft) (ft) (ft/sec) (hr) A4 SHEET 99 0.1363 0.240 0.113 SHALLOW 30 0.2000 0.050 0.001 Time of Concentration .114 WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:54:48 PM Dan Sub -Area Identifier A4 Valley Ridge Addition Lot 4 Existing Washington County, Nebraska Sub -Area Land Use and Curve Number Details Hydrologic Sub -Area Land Use Soil Area Group (ac) ------------------------------------------------------------------ Woods - grass combination (good) B .76 Total Area / Weighted Curve Number .76 Curve Number 58 58 WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:54:48 PM F' d�uEn wa rt wo z h N 'J W I W N w I p o r a v H i rvw N N W I N ct O 1 C N• H I C W Ln IIDD W I N• I rt ct •• co 1 0 F< v ry Op I w C a I H- H I t- 0 kQ V i 11 N I F ID •• I N V I N D t1 A w Le I m a (D i 4c o H ti rt cn I .. N H. a 0. H. to v 5 N z w I W rt cn I F< a a f] I H r O I r a i C rt I IP `G I rt n (n I " F< ID H z i 7 I O C) I A. cn I I 01 I .. N I Y• O cn I p o (77 I �•' I I H N I N .p i p Fa N I `•' ry H > I z O It, 1 w w 1 m r i w i m D) i O C rt r CD ct 0 a% ti CD m w P) 0 n w x rt P) I I n m w w n N o rt e po H cc rcwtr'om N O ct H u. m W K C't• n • • m ct MJ :V4 a m o w a A��ct�p Cpto ww x H F. rt a 0;u W ro a, N W N C m ct a w a. o a � w N !* Z o F' - n P5, (D lD is k ID ID r r CD z w now vy r c m a a a• w 7 rt w P. tY Otj N O O = — ct H LQ \ (D r r Ic. N M• co ro xN n o ro co O rn Q. I N- I p I H H I IaD tori cit 0 r• C M tS cr rt rt H. 0 ❑ a rt d a a rt CJ a ID N I F- ro rr O p Dan Valley Ridge Addition Lot 4 Proposed Washington County, Nebraska Storm Data Rainfall Depth by Rainfall Return Period 2 -Yr 5 -Yr 10 -Yr 25 -Yr 50 -Yr 100 -Yr 1 -Yr (in) (in) (in) (in) (in) (in) (in) ------------------------------------------------------------------------------- 3.0 3.87 4.6 5.25 5.95 6.55 2.42 Storm Data Source: Washington County, NE (NRCS) Rainfall Distribution Type: Type II Dimensionless Unit Hydrograph: <standard> WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:08:29 PM ro P) W m r °a M a �lc�C i Pr.o W H C I W M CD CD P C I MP rf CO I H• n m I m p' w I H O O zo o N N r r ON m r N a m � � C rt w m rrrr N :) rr �C x m !zaw a O r• 10zn� m Cr o m w le ro PV 1 o D* co a. H z m a. av (D a H- A) w O N 'J X PL) Dan Valley Ridge Addition Lot 4 Proposed Washington County, Nebraska Hydrograph Peak/Peak Time Table Sub -Area Peak Flow and Peak Time (hr) by Rainfall Return Period or Reach 2 -Yr 5 -Yr 10 -Yr 25 -Yr 50 -Yr 100 -Yr Identifier (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) ---------------------------------------------------------------------- (hr) (hr) (hr) (hr) (hr) (hr) SUBAREAS A4 0.92 1.61 2.24 2.83 3.49 4.07 11.96 11.95 11.94 11.94 11.95 11.94 REACHES OUTLET 0.92 1.61 2.24 2.83 3.49 4.07 WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:08:29 PM Dan Sub -Area Drainage Identifier Area (ac) A4 .76 Total Area: .76 (ac) Valley Ridge Addition Lot 4 Proposed Washington County, Nebraska Sub -Area Summary Table Time of Curve Receiving Concentration Number Reach (hr) -------------------------------- 0.114 73 Outlet Sub -Area Description WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:08:29 PM Dan Valley Ridge Addition Lot 4 Proposed Washington County, Nebraska Sub -Area Time of Concentration Details Sub -Area Flow Mannings's End Wetted Travel Identifier/ Length Slope n Area Perimeter Velocity Time -------------------------------------------------------------------------------- (ft) (ft/ft) (sq ft) (ft) (ft/sec) (hr) A4 SHEET 99 0.1363 0.240 0.113 SHALLOW 30 0.2000 0.050 0.001 Time of Concentration .114 WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:08:29 PM Dan Sub -Area Identifier A4 Valley Ridge Addition Lot 4 Proposed Washington County, Nebraska Sub -Area Land Use and Curve Number Details Hydrologic Sub -Area Land Use Soil Area Group (ac) --------------------------------------------------------------- Open space; grass cover > 75% (good) B .37 Paved parking lots, roofs, driveways B .25 Woods - grass combination (good) B .14 Total Area / Weighted Curve Number .76 Curve Number 61 98 58 73 WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:08:29 PM ATTACHMENT NO. 8 Fig use 6-1 Approximat-e delerrtion ha -sin routing for ", nd:31 I3,pey 1, 1A, I1,;md 111 LOT 4 - STORAGE CALCULATIONS (3 PAGES) DETENTION BASIN SIZE .6 .5 f'3 .4 M CD E oa b a 0.258 .2 qo = 2.32 cfs, qi = 4.07 cfs qo/qi = 2.37/4.16 = 0.558 VsNr = 0.258 Vr = 53.33Q(A) Vr =-53.33(3.60-2.15)(0.0012) = 0.093 ac -ft.. ----- = 1045 cubic feet - NOTES: Q = DIFFERENCE BETWEEN EXISTING AND PROPOSED (DIRECT RUNOFF). A = AREA IN SQUARE MILES STORAGE VOLUME REQUIRED = 1045 C.F. - - ---- — - I ,2 .3 _4 .5 0.558 6 ,7 .8 P k outflow discharge qo Peak inilaw discharge ( qi Figure 2-1 Solution of runoff equation. 8 7 6 Cl) aD 5 U Q � 4 0 0 U m 3 w 2.15 2 1 LOT 4 - STORAGE CALCULATIONS DIRECT RUNOFF - EXISTING 1 2 3 4 5 6 6.55 7 Rainfall (P), inches 8 9 10 11 12 Figure 2-1 Solution of runoff equation. LOT 4 - STORAGE CALCULATIONS DIRECT RUNOFF - PROPOSED I 7 Curves on this sheet are for the I - case la = 0.2S, so that P -0.2S P+0.8S - - - - -- - - - - I I `.. pO I I I (Di _r_ 5 �� - - - ----- cbO -- �- I � - � 4- - 3.60 3 ---- - -- --- - - - - - �0 - 2 --- ---- - --- I ---- -- ---- --- ---- ----- — --0- -- -- - - 0 1 2 3 4 5 6 6.55 7 8 9 10 11 12 Rainfall (P), inches E c H Id I m H 0 0 0 0 ro P) W m r C P- m ct Y- o H Lni a rr w i m r I a I rY I m I a I G rr r m rt En C b' I H m a(D W d � a rt P) N P. O rt 0 h m C1 I -h 5 W I Y• m a 17 K m Y r t7 o I h o ra p rt 1 roa 1 m m nm�rr�� m N- ED w X m rt C I 0 P. Y• En a v 0 w I --. cn r Y• m rt rt m w Y• J I -- ti 0 F- m rr �e 0 i w z 0 H I Y- 5 p Ln 0 m 0, PV 1 w i a m Ih rs � a i k w / rt cr a I Y o •• I p I m I (D r cat m I n rt I A w rt d 1e i co m naw i H w o I w CD rorr ill H p I 0 H a 0 Pi fT U7 I .•. N Y- C7 H- rt a mcn'n c I- C1 1 n r O I r q I I m � rr I m � I rt m m n P. :1 Ln I � N -o Ln to I C7 I ro Ln I m I ff ft :0 i o A I a rn I I I r miLn I W O Ln i � to I K I � I I I I N I r N 1 `•' ri H Lni a rr w i m r I a I rY I m I a I G rr r m rt En C b' I H m a(D W d � a rt P) P. O rt 0 h m ra a 0'0 m M 0 rt H u- H m wLe rtn • • rt - :4 m o w m w nm�rr�� Y- Y- a (n m N- w X m rrr a k 0 0 P. Y• En rmi W r Y• m w 0 F- m rr I H / Y• ;u z 0 H I Y- 5 p Ln 0 m 0, PV 1 w C/3 C m Ih rs M k w / rt cr w 0 d r cat m d a P) rt d z a m w m naw i H w m m r- rr I w CD rorr > N w a 0 C.. Fl- rr Y H- rt 0 m p.. r D:o crt H W m rr cn m Y- co m � [] N k o Y- r m m rt P. :1 Ln cn Dan Valley Ridge Addition Lot 5 Existing Washington County, Nebraska Storm Data Rainfall Depth by Rainfall Return Period 2 -Yr 5 -Yr 10 -Yr 25 -Yr 50 -Yr 100 -Yr 1 -Yr (in) (in) (in) (in) (in) (in) (in) ------------------------------------------------------------------------------- 3.0 3.87 4.6 5.25 5.95 6.55 2.42 Storm Data Source: Washington County, NE (NRCS) Rainfall Distribution Type: Type II Dimensionless Unit Hydrograph: <standard> WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:52:22 PM r O ;u > w I H 0 N C H D w 1 0" C H p7 L+] I N (DD > y y I W 0 N 1 m?a I rt Lo w N N O O w w v J E a N E � C (D r N m 0 0 m PI o o m to 7 c* "C N A cn ;V a o r - C t7 R ro nxw m rr N- m a 'C N X rr y H (D CL ft r rt w m a o co 0 X a Dan Valley Ridge Addition Lot 5 Existing Washington County, Nebraska Hydrograph Peak/Peak Time Table Sub -Area Peak Flow and Peak Time (hr) by Rainfall Return Period or Reach 2 -Yr 5 -Yr 10 -Yr 25 -Yr 50 -Yr 100 -Yr Identifier (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) ---------------------------------------------------------------------- (hr) (hr) (hr) (hr) (hr) (hr) SUBAREAS A5 0.83 1.45 2.03 2.58 3.20 3.74 12.01 11.99 11.98 11.98 11.98 11.97 REACHES OUTLET 0.83 1.45 2.03 2.58 3.20 3.74 WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:52:22 PM Dan Sub -Area Drainage Identifier Area (ac) A5 .76 Total Area: .76 (ac) Valley Ridge Addition Lot 5 Existing Washington County, Nebraska Sub -Area Summary Table Time of Curve Receiving Concentration Number Reach (hr) -------------------------------- 0.148 72 Outlet Sub -Area Description WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:52:22 PM Dan Valley Ridge Addition Lot 5 Existing Washington County, Nebraska Sub -Area Time of Concentration Details Sub -Area Flow Mannings's End Wetted Travel Identifier/ Length Slope n Area Perimeter Velocity Time -------------------------------------------------------------------------------- (ft) (ft/ft) (sq ft) (ft) (ft/sec) (hr) A5 SHEET 99 0.0720 0.240 0.146 SHALLOW 25 0.0720 0.050 0.002 Time of Concentration .148 WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:52:22 PM Dan Valley Ridge Addition Lot 5 Existing Washington County, Nebraska Sub -Area Land Use and Curve Number Details Sub -Area Hydrologic Sub -Area Curve Identifier Land Use Soil Area Number Group (ac) -------------------------------------------------------------------------------- A5 Woods - grass combination (good) C .76 72 Total Area / Weighted Curve Number .76 72 WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:52:22 PM r 00 co coH O 0 07 a in F'- a rt m P. r°t 0 M3 m w o Nw 0 rr (D - m P- m m to M rr 0 H C C r- H F0+• C (D rtrt.. �c 00 a H H O LG �R (D H (D ro" 0' A H :E m e w rtro m w m x 0 r- a�0 w HW H rt Q, 0 n 0 C 0 rr k z C•] z n n 3 rn Ln Ln 00 k H r0pIZHtv m r0P)W0(D (D 0 rr H �- H W k .. R n •• N rt m (D .. m:4zrco im b'rOrN0) n0M r C�m(nK ww x H r0 0 ° H 0 0 R 0 o W r m m C (D rt a� W a o a 0 r• ED rr z 0 � 0 x N CD O H k i N r r m z a ryas CDD (HD H. rt, > rm P. a" r• 0 rt r- r- rr 0 m 0 •• o n 0 `* m r r Ln to P. co ro N ro m 0 m (D a E U7 al E I W I 0 I H N I Ln (D Ln c rt n r- C M H n N w 0 rr rt 0 0 w rt d w rt o w m to I rr 0 0 Dan Valley Ridge Addition Lot 5 Proposed Washington County, Nebraska Storm Data Rainfall Depth by Rainfall Return Period 2 -Yr 5 -Yr 10 -Yr 25 -Yr 50 -Yr 100 -Yr 1 -Yr (in) (in) (in) (in) (in) (in) (in) ---------------------------------------------------------------------------- 3.0 3.87 4.6 5.25 5.95 6.55 2.42 Storm Data Source: Washington County, NE (NRCS) Rainfall Distribution Type: Type II Dimensionless Unit Hydrograph: <standard> WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:50:41 PM F-' r r W CD 00 N .. o � o W K r� E a !A rt LO F N rr r 1-1 n 0 0 m Ed 7 ct tD 0 O+ W Q. 0 r• C ro p. ro 0 " Q N rt 0 CD a ro X O 9 m ¢. H Z O A- b w rrr r rt r• m a O N :3 X a 0a a � ci aO to w H Ct] t J I N N ✓y Ca I H,0 N I ce x a N .. o � o W K r� E a !A rt LO F N rr r 1-1 n 0 0 m Ed 7 ct tD 0 O+ W Q. 0 r• C ro p. ro 0 " Q N rt 0 CD a ro X O 9 m ¢. H Z O A- b w rrr r rt r• m a O N :3 X a Dan Valley Ridge Addition Lot 5 Proposed Washington County, Nebraska Hydrograph Peak/Peak Time Table Sub -Area Peak Flow and Peak Time (hr) by Rainfall Return Period or Reach 2 -Yr 5 -Yr 10 -Yr 25 -Yr 50 -Yr 100 -Yr Identifier (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (hr) (hr) (hr) (hr) (hr) (hr) ---------------------------------------------------------------------------------- SUBAREAS A5 1.49 2.27 2.94 3.55 4.22 4.79 11.98 11.97 11.97 11.97 11.97 11.96 REACHES OUTLET 1.49 2.27 2.94 3.55 4.22 4.79 WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:50:41 PM Dan Sub -Area Drainage Identifier Area (ac) A5 .76 Total Area: .76 (ac) Valley Ridge Addition Lot 5 Proposed Washington County, Nebraska Sub -Area Summary Table Time of Curve Receiving Concentration Number Reach (hr) -------------------------------- 0.148 82 Outlet Sub -Area Description WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:50:41 PM Dan Valley Ridge Addition Lot 5 Proposed Washington County, Nebraska Sub -Area Time of Concentration Details Sub -Area Flow Mannings's End Wetted Travel Identifier/ Length Slope n Area Perimeter Velocity Time -------------------------------------------------------------------------------- (ft) (ft/ft) (sq ft) (ft) (ft/sec) (hr) A5 SHEET 99 0.0720 0.240 0.146 SHALLOW 25 0.0720 0.050 0.002 Time of Concentration .148 WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:50:41 PM Dan Sub -Area Identifier A5 Valley Ridge Addition Lot 5 Proposed Washington County, Nebraska Sub -Area Land Use and Curve Number Details Hydrologic Sub -Area Land Use Soil Area Group (ac) --------------------------------------------------------------- Open space; grass cover > 75% (good) C .37 Paved parking lots, roofs, driveways C .25 Woods - grass combination (good) C .14 Total Area / Weighted Curve Number .76 Curve Number 74 98 72 82 WinTR-55, Version 1.00.10 Page 1 11/18/2018 10:50:41 PM ATTACHMENT NO. 11 Figure 6-1 Approxim ate del(rntirm lxmsin miutin;g for rainfall I, I-% II, and III LOT 5 - STORAGE CALCULATIONS (3 PAGES) DETENTION BASIN SIZE Yj .6 I' > .4 m 0 C 3 icc 2 0.186 i qo = 3.74 cfs, qi = 4.79 cfs qo/qi = 3.74/4.79 = 0.78 Vs/Vr = 0.186 Vr = 53.33Q(A) Vr =.53.33(4.42-3.45)(0.0012) = 0.062 ac -ft. Vs = 0. 186(0.062) = 0.012 ac -ft. = 505 cubic feet NOTES: Q = DIFFERENCE BETWEEN EXISTING AND PROPOSED (DIRECT RUNOFF). - - --- - - - - - - - - --- --- -- - — — -- --- - - -- - - --- -A=-AREA-IN-,SQUARE-MILES- — ---- _. i STORAGE VOLUME REQUIRED = 505 C.F. i Peak outflow discharger qa . Peak inflow discharge qi 0.78 r Figure 2-1 Solution of runoff equation. LOT 5 - STORAGE CALCULATIONS DIRECT RUNOFF - PROPOSED 8 II II I 7 I Curves on this sheet are for the i I I _ - - --- - -- - - - - -. - - -- — case la = 0.2S, so that P -0.2S P+0.8S 111i11111 1Cn 5 00 - - -- .; 4.42- .42 10 4 � � I - 3 - ----- - - - I i - - — - - - - - -- - -- -- - - - --- - _ - - - - --- - — 1 0 I I 0 1 2 3 4 5 6 6.55 7 8 9 10 11 12 Rainfall (P), inches