HomeMy WebLinkAboutARROWHEAD COTTAGES - MJA/FDP - FDP160004 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT301 N. Howes Street, Suite 100, Fort Collins, CO 80521 970.221.4158 www.northernengineering.com
January 27, 2015
Wes Lamarque
City of Fort Collins Stormwater Utility
700 Wood Street
Fort Collins, CO 80521
RE: Preliminary Drainage Addendum to the
Final Drainage and Erosion Control Report for Centre Avenue Residences
Mr. Lamarque:
Northern Engineering is pleased to submit this Drainage Addendum for your review. This
addendum serves to outline the drainage design for the Arrowhead Cottages project, and to
show compliance with overall drainage concepts outlined in previous reports and studies.
This addendum has been prepared in accordance with the Fort Collins Stormwater Criteria
Manual (FCSCM) and serves to document the stormwater impacts associated with the
proposed project. We understand that review by the City is to assure general compliance
with standardized criteria.
If you should have any questions as you review this addendum, please feel free to contact
us.
Sincerely,
NORTHERN ENGINEERING SERVICES, INC.
Danny Weber Ryan Banning, PE
Project Engineer Project Manager
Arrowhead Cottages
Page|2
The Arrowhead Cottages project is a Major Amendment to the Centre Avenue Residences
site plan, previously submitted and approved by the City of Fort Collins. This addendum is
intended to document the associated stormwater impacts of the revised site development
plan on the existing and proposed storm drainage systems.
The project area has been previously studied as part of the Amended Master Drainage Plan
for the Centre for Advanced Technology (dated February 1987), the Final Drainage Report
for the Seventh Filing of the Centre for Advanced Technology (dated August 1988), and
the Final Drainage and Erosion Control Report for Centre Avenue Residences (dated
October 2009). The drainage plan for this proposed project will conform to these
previously approved reports.
Historically, the majority of the site sheet flowed north to an existing detention pond located
in the northern portion of the site. A small area of the site along Centre Avenue and
Worthington Circle sheet flowed into the adjacent curb and gutter where it was routed to an
existing inlet at the intersection between Centre Avenue and Worthington Circle.
The proposed site will follow similar drainage patterns as historical. The majority of the site
basins will be collected by existing and proposed storm sewer systems, where the flows will
be routed to the existing detention facility. The basin which do not directly flow to the
existing detention pond are described below:
Basin OS1 is a small basin along the Worthington Circle Right-of-Way. Historically, flow
from this basin sheet drained north directly to the existing detention pond. As proposed,
the runoff will enter the Worthington Circle curb and gutter where it will be routed north to
the existing detention pond. Runoff from this basin is considered negligible (0.2 cubic feet
per second [cfs] for 100-yr event) and, therefore, the existing storm sewer system is not
analyzed. This is similar to the previously approved Centre Avenue Residences
development plan.
Basins OS2 and E are the southern-most basins along the Centre Avenue and Worthington
Circle Right-of-Ways. Historically, flow from these basins sheet drained south or west into
either Worthington Circle or Centre Avenue Right-of-Ways, where it was collected by an
existing inlet on the north side of Centre Avenue. Stormwater runoff from Basin E will pass
through an engineered bio-swale designed to provide water quality measures and attenuate
the flows for minor events. This proposed bio-swale will treat a larger area of runoff then
the previously approved rain garden. Additionally, the total off-site runoff has reduced
during the 100-yr event from the Centre Avenue Residences developed site to the
Arrowhead Cottages developed site, from 1.5 cfs to 1.4 cfs, respectively.
Stormwater detention is provided by an existing detention facility constructed with the
Seventh Filing of the Centre for Advanced Technology and certified with the Final
Drainage and Erosion Control Report for Centre Avenue Residences. The total impervious
area for the previously approved Centre Avenue Residences site plan was approximately
48,905 square feet (SF). Through the use of permeable pavers located along the driveway
to building 2, the Arrowhead Cottages site plan results in a total impervious area of
Arrowhead Cottages
Page|3
approximately 48,892 SF. For this reason, no modifications to the existing detention pond
are proposed.
In conclusion, this addendum has been prepared in accordance with the Fort Collins
Stormwater Criteria Manual (FCSCM) and complies with assumptions from previous
drainage reports.
APPENDIX A
HYDROLOGIC COMPUTATIONS
CHARACTER OF SURFACE:
Runoff
Coefficient
Percentage
Impervious Project: Arrowhead Cottages
Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: D. Weber
Asphalt ……....……………...……….....…...……………….………………………………….0.95 . 100 Date:
Concrete …….......……………….….……….………………..….………………………………… 0.95 90
Gravel ……….…………………….….…………………………..……………………………….0.50 . 40
Roofs …….…….………………..……………….…………………………………………….0.. 95 90
Concrete Pavers…………………………...………………..…………………………………………….0.40 . 22
Lawns and Landscaping
Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0
Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0 2-year Cf
= 1.00 100-year Cf
= 1.25
Basin ID
Basin Area
(s.f.)
Basin Area
(ac)
Area of
Asphalt
(ac)
Area of
Concrete
(ac)
Area of
Roofs
(ac)
Area of
Gravel
(ac)
Area of
Concrete
Pavers
(ac)
Area of
Lawns and
Landscaping
(ac)
2-year
Composite
Runoff
Coefficient
10-year
Composite
Runoff
Coefficient
100-year
Composite
Runoff
Coefficient
Composite
% Imperv.
A1 1,334 0.03 0.00 0.00 0.01 0.00 0.00 0.02 0.57 0.57 0.72 41.5
A2 1,244 0.03 0.00 0.01 0.00 0.00 0.00 0.02 0.47 0.47 0.59 28.4
A3 2,034 0.05 0.00 0.02 0.01 0.00 0.00 0.01 0.78 0.78 0.97 68.1
A4 1,780 0.04 0.00 0.01 0.02 0.00 0.00 0.01 0.72 0.72 0.90 60.7
A5 2,841 0.07 0.00 0.01 0.02 0.00 0.00 0.03 0.62 0.62 0.78 47.6
Overland Flow, Time of Concentration:
Project: Arrowhead Cottages
Calculations By:
Date:
Gutter/Swale Flow, Time of Concentration:
Tt
= L / 60V
Tc
= Ti
+ Tt
(Equation RO-2)
Velocity (Gutter Flow), V = 20·S
½
Velocity (Swale Flow), V = 15·S
½
NOTE: C-value for overland flows over grassy surfaces; C = 0.25
Is Length
>500' ?
C*Cf
(2-yr
Cf=1.00)
C*Cf
(10-yr
Cf=1.00)
C*Cf
(100-yr
Cf=1.25)
Length,
L
(ft)
Slope,
S
(%)
Ti
2-yr
(min)
Ti
10-yr
(min)
Ti
100-yr
(min)
Length,
L
(ft)
Slope,
S
(%)
Velocity,
V
(ft/s)
Tt
(min)
Length,
L
(ft)
Slope,
S
(%)
Velocity,
Rational Method Equation: Project: Arrowhead Cottages
Calculations By:
Date:
From Section 3.2.1 of the CFCSDDC
Rainfall Intensity:
A1 A1 0.03 5.0 5.0 5.0 0.57 0.57 0.72 2.85 4.87 9.95 0.0 0.1 0.2
A2 A2 0.03 7.3 7.3 6.8 0.47 0.47 0.59 2.52 4.31 9.06 0.0 0.1 0.2
A3 A3 0.05 5.0 5.0 5.0 0.78 0.78 0.97 2.85 4.87 9.95 0.1 0.2 0.5
A4 A4 0.04 6.4 6.4 5.9 0.72 0.72 0.90 2.67 4.56 9.63 0.1 0.1 0.4
A5 A5 0.07 5.5 5.5 5.1 0.62 0.62 0.78 2.76 4.72 9.95 0.1 0.2 0.5
A6 A6 0.17 5.0 5.0 5.0 0.85 0.85 1.00 2.85 4.87 9.95 0.4 0.7 1.7
A7 A7 0.08 5.0 5.0 5.0 0.81 0.81 1.00 2.85 4.87 9.95 0.2 0.3 0.8
A8 A8 0.03 5.0 5.0 5.0 0.70 0.70 0.87 2.85 4.87 9.95 0.1 0.1 0.3
B1 B1 0.04 5.3 5.3 5.0 0.25 0.25 0.31 2.85 4.87 9.95 0.0 0.0 0.1
B2 B2 0.03 5.0 5.0 5.0 0.61 0.61 0.76 2.85 4.87 9.95 0.0 0.1 0.2
B3 B3 0.15 5.0 5.0 5.0 0.90 0.90 1.00 2.85 4.87 9.95 0.4 0.7 1.5
B4 B4 0.04 5.0 5.0 5.0 0.25 0.25 0.31 2.85 4.87 9.95 0.0 0.0 0.1
B5 B5 0.10 6.8 6.8 6.3 0.28 0.28 0.35 2.60 4.44 9.31 0.1 0.1 0.3
C C 0.08 5.0 5.0 5.0 0.99 0.99 1.00 2.85 4.87 9.95 0.2 0.4 0.8
D D 0.38 5.0 5.0 5.0 0.81 0.81 1.00 2.85 4.87 9.95 0.9 1.5 3.8
E E 0.19 5.0 5.0 5.0 0.60 0.60 0.74 2.85 4.87 9.95 0.3 0.6 1.4
F F 0.65 15.2 15.2 14.3 0.38 0.38 0.47 1.87 3.19 6.71 0.5 0.8 2.1
G G 0.19 9.5 9.5 9.3 0.25 0.25 0.31 2.30 3.93 8.03 0.1 0.2 0.5
OS1 OS1 0.03 5.0 5.0 5.0 0.44 0.44 0.55 2.85 4.87 9.95 0.0 0.1 0.2
OS2 OS2 0.11 7.5 7.5 6.9 0.34 0.34 0.42 2.52 4.31 9.06 0.1 0.2 0.4
Intensity,
i10
(in/hr)
Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1
C10
Area, A
(acres)
Intensity,
i2
(in/hr)
100-yr
Tc
(min)
DEVELOPED RUNOFF COMPUTATIONS
C100
Design
Point
Flow,
Q100
(cfs)
Flow,
Q2
(cfs)
10-yr
Tc
(min)
2-yr
Tc
(min)
C2
Flow,
Q10
(cfs)
Intensity,
i100
APPENDIX B
HYDRAULIC COMPUTATIONS
APPENDIX B.1
STORM SEWERS
APPENDIX B.2
INLETS
APPENDIX C
EROSION CONTROL REPORT
Arrowhead Cottages
EROSION CONTROL REPORT
A comprehensive Erosion and Sediment Control Plan (along with associated details) has
been included with the final construction drawings. It should be noted, however, that any
such Erosion and Sediment Control Plan serves only as a general guide to the Contractor.
Staging and/or phasing of the BMPs depicted, and additional or different BMPs from those
included may be necessary during construction, or as required by the authorities having
jurisdiction.
It shall be the responsibility of the Contractor to ensure erosion control measures are
properly maintained and followed. The Erosion and Sediment Control Plan is intended to
be a living document, constantly adapting to site conditions and needs. The Contractor
shall update the location of BMPs as they are installed, removed or modified in conjunction
with construction activities. It is imperative to appropriately reflect the current site
conditions at all times.
The Erosion and Sediment Control Plan shall address both temporary measures to be
implemented during construction, as well as permanent erosion control protection. Best
Management Practices from the Volume 3, Chapter 7 – Construction BMPs will be utilized.
Measures may include, but are not limited to, silt fencing and/or wattles along the disturbed
perimeter, gutter protection in the adjacent roadways and inlet protection at existing and
proposed storm inlets. Vehicle tracking control pads, spill containment and clean-up
procedures, designated concrete washout areas, dumpsters, and job site restrooms shall
also be provided by the Contractor.
To ensure stormwater quality is achieved long after the construction of the project, one
permanent Stormwater Quality BMP is included within the design. Located at the northern
portion of the project site, an Extended Detention Basin (EDB) is being proposed. This
measure will treat all of the runoff draining through the property prior to reaching the
historic outfall.
The Final Public Improvement Construction Plan contains a full-size Erosion Control Plan as
well as a separate sheet dedicated to Erosion Control Details. In addition to this report and
the referenced plan sheets, the Contractor shall be aware of, and adhere to, the applicable
requirements outlined in any existing Development Agreement(s) of record, as well as the
Development Agreement, to be recorded prior to issuance of the Development Construction
Permit. Also, the Site Contractor for this project may be required to secure a Stormwater
Construction General Permit from the Colorado Department of Public Health and
Environment (CDPHE), Water Quality Control Division – Stormwater Program, before
commencing any earth disturbing activities. Prior to securing said permit, the Site
Contractor shall develop a comprehensive StormWater Management Plan (SWMP) pursuant
to CDPHE requirements and guidelines. The SWMP will further describe and document the
ongoing activities, inspections, and maintenance of construction BMPs.
MAP POCKET
DR1 – OVERALL DRAINAGE EXHIBIT
ST
ST ST
ST ST
ST ST
ST
ST
ST
ST
ST
ST ST ST ST
ST
ST ST ST
ST
ST
ST
ST
ST ST
ST
ST ST
ST ST
ST
ST ST
ST ST
ST ST
ST
ST ST ST
ST
ST
ST
ST
ST
ST
ST ST
ST
ST ST ST
ST
ST ST
ST ST ST
ST ST ST
ST
ST
ST ST
ST
ST
ST
ST
ST
CENTRE AVENUE
WORTHINGTON
CIRCLE
EXISTING
STUCCO BUILDING
FFE=~5048.1
NEW MERCER DITCH
BLDG 2
BLDG 1
GARAGE
EXISTING
APARTMENT BUILDING
FFE=~5049.0
A1
A1
A2
A3
A4
A5 A8
A6
A7
A2
A3
A4
A5
A8
A6
A7
B1
B1
B2
B2
B3
B4
B4
B5
B5
C
C
D
D
F
F
G
G
E
E
OS1
OS1
OS2
OS2
B3
These drawings are
instruments of service
provided by Northern
Engineering Services, Inc.
and are not to be used for
any type of construction
unless signed and sealed by
a Professional Engineer in
the employ of Northern
Engineering Services, Inc.
NOT FOR CONSTRUCTION
200 South College Avenue, Suite 010
Fort Collins, Colorado 80524
N O R T H E RN
PHONE: 970.221.4158 FAX: 970.221.4159
www.northernengineering.com
DR1
CALL UTILITY NOTIFICATION CENTER OF
COLORADO
Know what's
R
City Engineer Date
Date
Date
Date
Date
Stormwater Utility
Parks & Recreation
Traffic Engineer
Date
Water & Wastewater Utility
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Environmental Planner
NORTH
( IN FEET )
1 inch = ft.
30 0 30 Feet
30
60 90
LEGEND:
PROPOSED CONTOUR
PROPOSED STORM SEWER
PROPOSED SWALE
EXISTING CONTOUR
PROPOSED CURB & GUTTER
PROPERTY BOUNDARY
PROPOSED INLET
A
DESIGN POINT
FLOW ARROW
DRAINAGE BASIN LABEL
BASIN
DESIGNATION
BASIN
AREA (AC)
DRAINAGE BASIN BOUNDARY
PROPOSED SWALE SECTION
1 1
B2
1.45 ac
RUNOFF SUMMARY TABLE
DESIGN
POINT
BASIN
ID
TOTAL
AREA
(acres)
C2 C10 C100
2-yr Tc
(min)
10-yr Tc
(min)
100-yr
Tc
(min)
Q2
(cfs)
Q10
(cfs)
Q100
(cfs)
A1 A1 0.03 0.57 0.57 0.72 5.0 5.0 5.0 0.0 0.1 0.2
A2 A2 0.03 0.47 0.47 0.59 7.3 7.3 6.8 0.0 0.1 0.2
A3 A3 0.05 0.78 0.78 0.97 5.0 5.0 5.0 0.1 0.2 0.5
A4 A4 0.04 0.72 0.72 0.90 6.4 6.4 5.9 0.1 0.1 0.4
A5 A5 0.07 0.62 0.62 0.78 5.5 5.5 5.1 0.1 0.2 0.5
A6 A6 0.17 0.85 0.85 1.00 5.0 5.0 5.0 0.4 0.7 1.7
A7 A7 0.08 0.81 0.81 1.00 5.0 5.0 5.0 0.2 0.3 0.8
A8 A8 0.03 0.70 0.70 0.87 5.0 5.0 5.0 0.1 0.1 0.3
B1 B1 0.04 0.25 0.25 0.31 5.3 5.3 5.0 0.0 0.0 0.1
B2 B2 0.03 0.61 0.61 0.76 5.0 5.0 5.0 0.0 0.1 0.2
B3 B3 0.15 0.90 0.90 1.00 5.0 5.0 5.0 0.4 0.7 1.5
B4 B4 0.04 0.25 0.25 0.31 5.0 5.0 5.0 0.0 0.0 0.1
B5 B5 0.10 0.28 0.28 0.35 6.8 6.8 6.3 0.1 0.1 0.3
C C 0.08 0.99 0.99 1.00 5.0 5.0 5.0 0.2 0.4 0.8
D D 0.38 0.81 0.81 1.00 5.0 5.0 5.0 0.9 1.5 3.8
E E 0.19 0.60 0.60 0.74 5.0 5.0 5.0 0.3 0.6 1.4
F F 0.65 0.38 0.38 0.47 15.2 15.2 14.3 0.5 0.8 2.1
G G 0.19 0.25 0.25 0.31 9.5 9.5 9.3 0.1 0.2 0.5
OS1 OS1 0.03 0.44 0.44 0.55 5.0 5.0 5.0 0.0 0.1 0.2
OS2 OS2 0.11 0.34 0.34 0.42 7.5 7.5 6.9 0.1 0.2 0.4
(in/hr)
Basin(s)
D. Weber
January 27, 2016
Q = C f ( C )( i )( A )
D:\Projects\374-018\Drainage\Hydrology\374-018_Rational.xlsx\Direct-Runoff
V
(ft/s)
Tt
(min)
2-yr
Tc
(min)
10-yr
Tc
(min)
100-yr
Tc
(min)
A1 A1 No 0.95 0.95 1.00 27 25.0 0.5 0.5 0.3 0 0.0 0.00 N/A 42 3.2 2.68 0.3 5.0 5.0 5.0
A2 A2 No 0.25 0.25 0.31 34 2.2 7.1 7.1 6.6 0 0.0 0.00 N/A 22 1.5 1.84 0.2 7.3 7.3 6.8
A3 A3 No 0.95 0.95 1.00 34 33.3 0.5 0.5 0.3 0 0.0 0.00 N/A 10 5.0 3.35 0.0 5.0 5.0 5.0
A4 A4 No 0.25 0.25 0.31 49 5.3 6.4 6.4 5.9 0 0.0 0.00 N/A 0 0.0 0.00 N/A 6.4 6.4 5.9
A5 A5 No 0.25 0.25 0.31 44 7.0 5.5 5.5 5.1 0 0.0 0.00 N/A 0 0.0 0.00 N/A 5.5 5.5 5.1
A6 A6 No 0.95 0.95 1.00 48 2.3 1.5 1.5 1.0 76 0.6 1.55 0.8 0 0.0 0.00 N/A 5.0 5.0 5.0
A7 A7 No 0.95 0.95 1.00 32 33.3 0.5 0.5 0.3 0 0.0 0.00 N/A 22 2.6 2.42 0.2 5.0 5.0 5.0
A8 A8 No 0.95 0.95 1.00 48 2.3 1.5 1.5 1.0 76 0.6 1.55 0.8 0 0.0 0.00 N/A 5.0 5.0 5.0
B1 B1 No 0.25 0.25 0.31 35 5.6 5.3 5.3 4.9 0 0.0 0.00 N/A 0 0.0 0.00 N/A 5.3 5.3 5.0
B2 B2 No 0.25 0.25 0.31 29 6.0 4.7 4.7 4.4 0 0.0 0.00 N/A 0 0.0 0.00 N/A 5.0 5.0 5.0
B3 B3 No 0.95 0.95 1.00 26 2.0 1.1 1.1 0.8 99 0.5 1.41 1.2 0 0.0 0.00 N/A 5.0 5.0 5.0
B4 B4 No 0.25 0.25 0.31 5 5.0 2.1 2.1 1.9 0 0.0 0.00 N/A 32 5.0 3.35 0.2 5.0 5.0 5.0
B5 B5 No 0.25 0.25 0.31 48 4.7 6.6 6.6 6.1 0 0.0 0.00 N/A 28 1.5 1.84 0.3 6.8 6.8 6.3
C C No 0.95 0.95 1.00 26 2.0 1.1 1.1 0.8 58 0.5 1.41 0.7 0 0.0 0.00 N/A 5.0 5.0 5.0
D D No 0.95 0.95 1.00 25 2.0 1.1 1.1 0.7 179 1.1 2.10 1.4 0 0.0 0.00 N/A 5.0 5.0 5.0
E E No 0.95 0.95 1.00 26 33.3 0.4 0.4 0.3 0 0.0 0.00 N/A 106 1.0 1.50 1.2 5.0 5.0 5.0
F F No 0.25 0.25 0.31 95 2.0 12.3 12.3 11.4 244 0.5 1.41 2.9 0 0.0 0.00 N/A 15.2 15.2 14.3
G G No 0.25 0.25 0.31 17 20.0 2.4 2.4 2.2 0 0.0 0.00 N/A 285 0.2 0.67 7.1 9.5 9.5 9.3
OS1 OS1 No 0.25 0.25 0.31 10 2.0 4.0 4.0 3.7 0 0.0 0.00 N/A 0 0.0 0.00 N/A 5.0 5.0 5.0
OS2 OS2 No 0.25 0.25 0.31 35 2.0 7.5 7.5 6.9 0 0.0 0.00 N/A 0 0.0 0.00 N/A 7.5 7.5 6.9
DEVELOPED TIME OF CONCENTRATION COMPUTATIONS
Gutter Flow Swale Flow
Design
Point
Basin
Overland Flow
D. Weber
January 27, 2016
Time of Concentration
(Equation RO-4)
( )
3
1
1 . 87 1 . 1 *
S
C Cf L
Ti
−
=
D:\Projects\374-018\Drainage\Hydrology\374-018_Rational.xlsx\Tc-2-yr_&_100-yr
A6 7,364 0.17 0.00 0.15 0.00 0.00 0.00 0.02 0.85 0.85 1.00 77.5
A7 3,293 0.08 0.00 0.01 0.05 0.00 0.00 0.02 0.81 0.81 1.00 71.4
A8 1,323 0.03 0.00 0.00 0.02 0.00 0.00 0.01 0.70 0.70 0.87 57.6
B1 1,623 0.04 0.00 0.00 0.00 0.00 0.00 0.04 0.25 0.25 0.31 0.0
B2 1,163 0.03 0.00 0.01 0.00 0.00 0.00 0.01 0.61 0.61 0.76 46.3
B3 6,615 0.15 0.00 0.10 0.04 0.00 0.01 0.00 0.90 0.90 1.00 83.2
B4 1,546 0.04 0.00 0.00 0.00 0.00 0.00 0.04 0.25 0.25 0.31 0.0
B5 4,157 0.10 0.00 0.00 0.00 0.00 0.00 0.09 0.28 0.28 0.35 3.5
C 3,666 0.08 0.00 0.04 0.05 0.00 0.00 0.00 0.99 0.99 1.00 95.0
D 16,696 0.38 0.00 0.18 0.12 0.00 0.00 0.08 0.81 0.81 1.00 71.8
E 8,350 0.19 0.00 0.00 0.09 0.00 0.00 0.10 0.60 0.60 0.74 44.5
F 28,449 0.65 0.00 0.02 0.10 0.00 0.00 0.54 0.38 0.38 0.47 16.1
G 8,448 0.19 0.00 0.00 0.00 0.00 0.00 0.19 0.25 0.25 0.31 0.0
OS1 1,510 0.03 0.00 0.01 0.00 0.00 0.00 0.03 0.44 0.44 0.55 24.4
OS2 4,913 0.11 0.00 0.01 0.00 0.00 0.00 0.10 0.34 0.34 0.42 11.1
DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS
Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I.
10-year Cf
= 1.00
January 27, 2016
D:\Projects\374-018\Drainage\Hydrology\374-018_Rational.xlsx\C-Values