537 E Grant St-20190828Civil
L,
Solutions, 5LL�
Bob P'. 1 g' Study
Lot 7 JPR Addition
1 1'
16439 Briar Street
Omaha, NE 68136-4154
402-895-5633
Bob Pearson is planning to build a 60'x 60' building with a concrete driveway to Grant Street.
The lot size is approximately 120 feet long by 80' wide. This building and lot size are exactly the
same as the building that was completed in late 2017. The drainage analysis for this building is
also exactly the same. Information from that drainage analysis has been copied into this report.
The City of Blair, NE requires that storm water runoff from the 100 year storm event on a
developed condition must not exceed the historic condition.
The drainage analysis for the existing site conditions was completed using the Win TR -55 Small
Watershed Hydrology program developed by the Natural Resources Conservation Service
(NRCS). Output data includes storm water runoff for the 5 -yr, 10-yr,25-yr,50-yr and 100 -yr
storm events.
EXISTING SITE CONDITIONS
From the Natural Resources Conservation Service, it was determined that the soils in this area
are classified as Luton Silty Clay. The Hydrologic Soil Group for this soil is C/D. Drainage
from the site is from the northwest to the southeast. Storm runoff from the entire site will be
used to design the required storage.
Total area = 0.28 acres = 0.0004 sq. miles
Brush Area = 0.26 acres
Paved Street = 0.02 acres
Q 100 =1.28 cfs
Total area: 0.28 acres = 0.0004 sq. miles
Grass Area = 0.12 acres
Paved ParkingiRoof = 0.16 acres
Q100: 1.50 cfs
www.civsolutions.com
Extend the south grading work from the building on Lot 5 to include the new building on Lot 7.
Each lot requires 540 cubic feet, for a total of 1080 cubic feet. By extending the berm from
elevation 1007.50 on Lot 5 around Lot 7, a total storage of 2,214 cubic feet is achieved.
The drainage calculations for this building and the building on Lot 5 are the same. The
attachments used for the Lot 5 building are also attached to this report.
No. 1 - Grading Plan Sheet
No. 2 - Historic Drainage Pattern (Lot 5 shown, Lot 7 is similar.)
No. 3 - Soil Description of the Site
No. 4 - Drainage Analysis for Existing Site Conditions (7 pages)
No. 5 - Drainage Analysis for Proposed Site Conditions (7 pages)
No. 6 - Direct Runoff (Q) from the Existing 100 Yr. Storm
No. 7 - Direct Runoff (Q) from the Proposed 100 Yr. Storm
No. 8 - Detention Basin (Storage Volume Calculations)
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Attachment No. 3
Soil Description of Site
Map Unit Description: Luton silty clay, rarely flooded ---Washington County, Nebraska
7791—Luton silty clay, rarely flooded
Map Unit Setting
National map unit symbol: f8lj
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
Luton, rarely flooded, and similar soils: 75 percent
Minor components: 25 percent
Estimates are based on observations, descriptions, and transects of
the mapunit
Description of Luton, Rarely Flooded
Setting
Landform: Backswamps on flood plains
Down-slope shape: Concave, linear
Across -slope shape: Concave, linear
Parent material: Clayey alluvium
Typical profile
A - 0 to 12 inches: silty clay
Bkg - 12 to 24 inches: silty clay
Bkssyg - 24 to 33 inches: silty clay
Bssyg - 33 to 43 inches: silty clay
Bkyg - 43 to 50 inches: silty clay
B'kg - 50 to 60 inches: silty clay
Properties and qualities
Slope: 0 to 2 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Poorly drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat):
Moderately low to moderately high (0.06 to 0.20 in/hr)
Depth to water table: About 0 to 18 inches
Frequency of flooding: Rare
Frequency of ponding: None
Calcium carbonate, maximum in profile: 15 percent
Gypsum, maximum in profile: 5 percent
Available water storage in profile: Moderate (about 6.6 inches)
Interpretive groups
Land capability classification (irrigated): 3w
Land capability classification (nonirrigated): 3w
Hydrologic Soil Group: C/D
USDA Natural Resources Web Soil Survey 8/24/2017
Conservation Service National Cooperative Soil Survey Page 1 of 2
Map Unit Description: Luton silty clay, rarely flooded ---Washington County, Nebraska
Ecological site: Clayey Overflow - Veg. zone 4 (R107XY069NE)
Hydric soil rating: Yes
Minor Components
Tieville, rarely flooded
Percent of map unit: 15 percent
Landform: Backswamps on flood plains
Down-slope shape: Concave, linear
Across -slope shape: Concave, linear
Ecological site: Clayey Overflow - Veg. zone 4 (R107XY069NE)
Hydric soil rating: Yes
Forney, rarely flooded
Percent of map unit: 10 percent
Landform: Backswamps, flood plains
Down-slope shape: Concave, linear
Across -slope shape: Concave, linear
Ecological site: Clayey Overflow - Veg. zone 4 (R107XY069NE)
Hydric soil rating: Yes
Data Source Information
Soil Survey Area: Washington County, Nebraska
Survey Area Data: Version 15, Sep 14, 2016
USDA Natural Resources Web Soil Survey 8/24/2017
Rim Conservation Service National Cooperative Soil Survey Page 2 of 2
Attachment No. 4
Drainage Analysis - Existing Site
(7 pages)
WinTR-55 Current Data Description
--- Identification Data ---
User: Dan Norman Date: 8/30/2017
Project: Bob Pearson Building 2 Units: English
SubTitle: Existing Site Drainage Areal Units: Acres
State: Nebraska
County: Washington
Filename: F:\Civil Solutions\Bob Pearson\Building Two\Existing Site Drainage.w55
--- Sub -Area Data ---
Name Description
------------------------------------
Al
Total area: .28 (ac)
Reach I Area(ac) RCN Tc
-------------------------------------
Outlet 0.28 67 0.1
--- 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 8/30/2017 6:44:38 PM
Dan Norman Bob Pearson Building 2
Existing Site Drainage
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 (MRCS)
Rainfall Distribution Type: Type II
Dimensionless Unit Hydrograph: <standard>
WinTR-55, Version 1.00.10 Page 1 8/30/2017 6:44:38 PM
Dan Norman Bob Pearson Building 2
Existing Site Drainage
Washington County, Nebraska
Watershed Peak Table
Sub -Area
Peak Flow by
Rainfall
Return Period
or Reach
5 -Yr 10 -Yr
25 -Yr
50 -Yr 100 -Yr
Identifier
-------------------------------------------------------------------------------
(cfs) (cfs)
(cfs)
(cfs) (cfs)
SUBAREAS
Al
0.43 0.64
0.84
1.07 1.28
REACHES
OUTLET 0.43
0.64 0.84
WinTR-55, Version 1.00.10 Page 1
1.07 1.28
8/30/2017 6:44:38 PM
Dan Norman Bob Pearson Building 2
Existing Site Drainage
Washington County, Nebraska
Hydrograph Peak/Peak Time Table
Sub -Area Peak Flow and Peak Time (hr) by Rainfall Return Period
or Reach 5 -Yr 10 -Yr 25 -Yr 50 -Yr 100 -Yr
Identifier (cfs) (cfs) (cfs) (cfs) (cfs)
(hr) (hr) (hr) (hr) (hr)
----------------------------------------------------------------------------------
SUBAREAS
Al 0.43 0.64 0.84 1.07 1.28
11.95 11.94 11.94 11.94 11.94
OUTLET 0.43 0.64 0.84 1.07 1.28
WinTR-55, Version 1.00.10 Page 1 8/30/2017 6:44:38 PM
Dan Norman Bob Pearson Building 2
Existing Site Drainage
Washington County, Nebraska
Sub -Area Summary Table
Sub -Area Drainage Time of Curve Receiving
Identifier Area Concentration Number Reach
(ac) (hr)
-------------------------------------------------------
Al .28 0.100 67 Outlet
Total Area: .28 (ac)
Sub -Area
Description
WinTR-55, Version 1.00.10 Page 1 8/30/2017 6:44:38 PM
Dan Norman Bob Pearson Building 2
Existing Site Drainage
Washington County, Nebraska
Sub -Area Time of Concentration Details
Sub -Area
Flow
Mannings's End Wetted
Identifier/
Length
Slope
n Area Perimeter Velocity
------------------------------------------------------------------------
(ft)
(ft/ft)
(sq ft) (ft) (ft/sec)
Al
SHEET
13
0.0200
0.011
SHALLOW
27
0.0820
0.050
SHALLOW
133
0.0132
0.050
Time of Concentration
Travel
Time
(hr)
0.004
0.002
0.020
0.1
WinTR-55, Version 1.00.10 Page 1 8/30/2017 6:44:38 PM
Dan Norman
Bob Pearson Building 2
Existing Site Drainage
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)
--------------------------------------------------------------------------------
Al Paved
parking lots, roofs, driveways
C
.02
98
Brush
- brush, weed, grass mix (good)
C
.26
65
Total
Area / Weighted Curve Number
.28
67
WinTR-55, Version 1.00.10 Page 1 8/30/2017 6:44:38 PM
Attachment No. 5
Drainage Analysis - Proposed Site
(7 pages)
WinTR-55 Current Data Description
--- Identification Data ---
User: Dan Norman Date: 8/30/2017
Project: Bob Pearson Building 2 Units: English
SubTitle: Proposed Site Drainage Areal Units: Acres
State: Nebraska
County: Washington
Filename: F:\Civil Solutions\Bob Pearson\Building Two\Proposed Site Drainage.w55
--- Sub -Area Data ---
Name Description Reach Area(ac) RCN Tc
------------------------------------------------------------------------------
Al Outlet 0.28 88 0.1
Total area: .28 (ac)
--- 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 8/30/2017 6:47:34 PM
Dan Norman Bob Pearson Building 2
Proposed Site Drainage
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 8/30/2017 6:47:34 PM
Dan Norman Bob Pearson Building 2
Proposed Site Drainage
Washington County, Nebraska
Watershed Peak Table
Sub -Area
Peak Flow by
Rainfall
Return Period
or Reach
5 -Yr 10 -Yr
25 -Yr
50 -Yr 100 -Yr
Identifier
----------------------------------------------------------------------------------
(cfs) (cfs)
(cfs)
(cfs) (cfs)
SUBAREAS
Al
1.12 1.39
1.64
1.91 2.14
REACHES
OUTLET 1.12 1.39 1.64 1.91 2.14
WinTR-55, Version 1.00.10 Page 1 8/30/2017 6:47:34 PM
Dan Norman
Bob Pearson Building 2
Proposed Site Drainage
Washington County, Nebraska
Hydrograph Peak/Peak Time Table
Sub -Area
Peak
Flow and Peak Time (hr) by Rainfall Return Period
or Reach
5 -Yr
10 -Yr 25 -Yr 50 -Yr 100 -Yr
Identifier
(cfs)
(cfs) (cfs) (cfs) (cfs)
------------------------------------------------------------------------------
(hr)
(hr) (hr) (hr) (hr)
SUBAREAS
Al
1.12
1.39 1.64 1.91 2.14
11.93
11.93 11.93 11.93 11.92
REACHES
OUTLET
1.12
1.39 1.64 1.91 2.14
WinTR-55, Version 1.00.10 Page 1 8/30/2017 6:47:34 PM
Dan Norman Bob Pearson Building 2
Proposed Site Drainage
Washington County, Nebraska
Sub -Area Summary Table
Sub -Area Drainage Time of Curve Receiving
Identifier Area Concentration Number Reach
(ac) (hr)
------------------------------------------------------
Al .28 0.100 88 Outlet
Total Area: .28 (ac)
Sub -Area
Description
-------------
WinTR-55, Version 1.00.10 Page 1 8/30/2017 6:47:34 PM
Dan Norman
Bob Pearson Building 2
Proposed Site Drainage
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)
--------------------------------------------------------------------------------
Al
SHEET
13
0.0200 0.011
0.004
SHALLOW
75
0.0100 0.050
0.013
CHANNEL
237
0.0100 0.030 1.06
4.21
1.995
0.033
Time of Concentration
0.1
WinTR-55, Version 1.00.10 Page 1 8/30/2017 6:47:34 PM
Dan Norman
Bob Pearson Building 2
Proposed Site Drainage
Washington County, Nebraska
Sub -Area Land Use and Curve Number
Details
Sub -Area
Hydrologic
Sub -Area
Identifier
Land Use
Soil
Area
--------------------------------------------------------------------------
Group
(ac)
Al Open
space; grass cover > 75% (good)
C
.12
Paved
parking lots, roofs, driveways
C
.16
Total
Area / Weighted Curve Number
.28
Curve
Number
74
98
88
WinTR-55, Version 1.00.10 Page 1 8/30/2017 6:47:34 PM
-� ATTACHMENT NO 6 - EXISTING SITE
DIRECT RUNOFF, 100 YR STORM
Curoes on this sheet are for the
Case la _ 0-2S, so, that _
(P-0.202
P+0.8 �i
s
w
L! d
fr >r
a 10, 11 12
Paliifall (P), inches
2-1 Sc:plutimi of .risnoff mR a-Lio rk.
ATTACHMENT NO 7 - PROPOSED SITE
DIRECT RUNOFF, 100 YR STORM
Curves on this sheet are tcor the
case la = 0.2S. so that 3 �
(P-0.2:)2
Q
P+0.$S
5.14`:` - =
cr�a -
leZ
10
f
r �
e
r =
r�
a 1 - 6 6.55 7 a ill 12
flgtve &1 Approximate doontion t.Ai-iin touting for ratinr ull tvw-+ 1, IA, Fl, and Ila ATTACHMENT NO. 8
DETENTION BASIN SZE
L
;>I 4
eta a;
F
O
0, = S
65 cc
0.24-
.2
qo 1.28 cfs, qi = 2:14 cfs
- - ---- - - _ _—_. — go/qi_=.1.28/2.11 =0_6.0__-_.—_
Vs/Vr = 0.243
- - _ Vr=-53,33Q(A) .
Vr 53.33(5.14-2.95)(0.00044) = 0.051 ac -ft.
1
0.243 0.0 -540 cubic feet
..--- --- ANDFE PROPOSED. I
} NOTES:- Q = DI RENGE-BETW EN -EXISTING
1
--.-- - - � - N-S@t1fkRE-M I L -ES----
c
STORAGE VOLUME REQ IRED = 540 C.F.
",kp
i
.3 _4 S
Peak outflo%a discharge qQ
Peak inflow d'isch arge
(210--VI-'d'Et-55. Sorn-nd 5cL. June IW'j
,6► -7 's