HomeMy WebLinkAbout1.03 Grading-Drainage Plan
Article 4-203.E
Grading and Drainage Plan
Ursa Operating Company
Speakman A Booster
Compressor
OA Project No. 015-3104
Denver Colorado Springs Phoenix Anniston Atlanta Niceville Parsons Pueblo Sacramento Washington, D.C.
2435 Research Parkway, Suite 300
Colorado Springs, Colorado 80920
Phone: 719.575.0100
Fax: 719.575.0208
matrixdesigngroup.com
February 5, 2016
Scott Aibner, P.L.S.
River Valley Survey, Inc.
110 E. 3rd Street Suite 213
Rifle, Colorado 81650
Ph: 970-379-7846
RE: Speakman A Pad Compressor Station Drainage Update
Dear Scott,
Per our discussion on the phone, it was explained that it is the intention to install a portable
booster compressor (on skid pads) on the existing Speakman A Injection Well Pad. The booster
compressor will be mobile, is small in stature, and non-permanent. The booster does not
increase the long term imperviousness of the site, and does not appear to impact the overall
drainage analysis of the site performed for the injection well. The terms and conditions as
outlined in the review process through Garfield County, questions received by the Garfield
County review engineer, and subsequent responses, during the injection well application will
still be applicable to this project. Water quality and erosion control measures should be
reviewed with the active management plan for the well pad, and if necessary updated and
monitored, during the construction process.
Please feel free to contact me directly if you have any questions.
Best Regards,
Gregory G. Shaner, PE
Senior Associate of Development Services
I
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40 0 20 40 80
GRAPHIC SCALE IN FEET
Existing Conditions Survey provided by
River Valley Survey, Inc. Dated 01-27-2014
These drawings have beeo prepared for the clieot
identified on the design sheet titleblock. Unless
these drawings bear a signed engineers seal, they
may be used only at owners sole risk.
No
0
0
0
This Drawing Not Valid Unless Latest Revision Initials Are Handwritteo
Description By Date
New facilities layout within pad site, updated BMP
.,.Sediment basin BMP. Pond to be 15' x 20'
4-ft depth. Low level hooded outlet box with
Engineer's Seal
Original Drawing Preparation
Approved Date By Date
CM 121412015 Drawn KTS 02/2014
Checked
Approved
Slope VP...: .... ,es
18" Depth
Ditch Extension
Typical Section
(not to scale)
~.-ies s1opev ......
12/4/15
CLJENT:
River Valley Survey, Inc.
PO Box 1301 110 East 3rd Street, Suite 213
SHEET TITLE:
Speakman A Pad
Grading and Drainage Plan
Rifle, CO 81650 Rifle, co 81650
Tcl970-625-4933 ~------------------+===-==-----------------j
SHEET NO. OF 1
1
Revision~
PROJECT: CREFILE: ENCiINEERINEi Clieot Approved Speakman A Pad 11'CORPO£ATfl:.D M:\CREjobfiles\00 I-Old Jobs Archive\910.20-Speakman A
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=· I• I D E S I G N G R 0 U P "lliil
River Valley Survey
c/o Mr. Scott Aibner PLS
110 E. 3rd Street
Rifle, Colorado 81650
RE : Speakman A Pad Garfield County Engineer Response
Dear Scott,
2435 Research Parkway, Suite 300
Colo rado Springs , Co l orado 80920
Phone : 719 .575.0100
Fax: 719.575.0208
matri xdes i gngroup.com
The follow i ng is a point response to the comments by Mountain Cross Engineering in their
letter dated May 28, 2014 regarding the Speakman A Injection Well: GAPA-7835 .
1. There appears to be fill that will be generated with the re-grading of the well pad . The
Applicant should addre ss how the fill will be managed .
Soil stockpiling, management and final vegetative acceptance is to be addressed by the
Olson and Associates consultant in the development of the erosion control and
construction activity permit monitoring.
2. There is a large discrepancy in the areas between the Historic and the Existing basin
delineations of the drainage analysis. It appears that the ex isting condition may split the
Hi stori c delineation in two ba sin , however only one ba sin appears to be included i n the
analysis . The Engineer for the Applicant should provide an explanation of how the ba sin
delineations were determined or revi se the analysi s to include the remaining area of
the Hi storic Ba sin .
The mapping has been revi sed per our discussion . In Exhibit 1-the Historic basin size
has been reduced to fit more naturally on the western ridgeline of the topography.
Exhibit 2 identifies the Ex isting Basin 1 and Existing Basin 2 which combined marginally
e xceeds the acreage (0.41 acres) of Historic Ba sin 1 . Basin flow summaries are in the
table below.
Basin Area %Imp. Tc Q (2 yr) Q (25 yr)
Hl 7.72ac 2% 20.46 0.46 cfs 6.27 cfs
El 6.40 ac 5% 22.20 0 .51 cfs 5.15 cfs
E2 1.73 ac 2% 16.98 0.11 cfs 1.54 cfs
El & E2 8.13 ac 4.4% 22 .20 0.61 cfs 6.48 cfs
Basin El & E2 have been basin routed together for a combined discharge using the more
conservative 8 .13 acres, but does not credit the offsite reduction of 0.41acres. If the
analysis is performed with a tributary area di scharge of 7 .72 acres the total flow is
Denver Colorado Springs Phoenix Anniston Atlanta Niceville Parsons Pueblo Sacramento Washington, D.C.
June 19, 2014
Page 2
below the historic amount due to the extended travel time through the pad.
Referencing the larger acerage, the calculated 25-year detention for the combined basin
would be 429 cf per the Detention Volume by Rational Volume Method which is
equivalent to 2' deep 14-ft by 14-ft. The proposed settlement/containment pond should
be sized large enough to provide this minor amount of attenuation and an extended
detention basin is not necessary.
3 . The Engineer for the Applicant should provide more detail on how the 1-hour
precipitation depths are determined from the 24-hour precipitation events.
The NOAA Atlas 2, Volume Ill -Colorado Precipitation-Frequency Atlas of the Western
United States Pages 13-17 covers the Interpretation of Results. From the 6-hour and 24-
hour results of the Atlas, the 1-hour precipitation-frequency values for the return
periods 2 yr and 100 yr can be estimated using the equations in Table 11. Plotting the
results on a nomogram is performed to obtain values for return periods greater than 2
year and le ss than 100-year. As discussed on the phone, the new Atlas 14 has been
uploaded online and 1-hour precipitation-frequency values can be sourced from direct
data from participating weather stations with NOAA.
4. The narrative for Section 7-204. Drainage and Erosion , in the Standards Analysi s portion
of the application materia ls describes detention that is different than proposed in the
drainage analysis .
Olson and Associates should modify the narrative to reflect the drainage report
memorandum. Detention through the settlement basin is being propose d, and the
narrative should be should be updated.
Plea se let me know if you have any que stion s.
Attached: Exh ibit 1-Historic map, Exhibit 2 -Existing map, Hydrology Sheet s
ma trixdes1gngraup . com
RlvER VALLEY SURVEY, lNc.
February 19, 2014
Ursa Operating Company LLC
792 Buckhorn Dr.
Rifle, Colorado 81650
RE: Speakman A Pad -Existing Conditions Review
Dear Sirs,
River Valley Survey, Inc. has completed an Existing Conditions Survey as the basis for
the Grading/Drainage/Erosion Plan. We have also prepared the construction drawings
associated with the pad and access road originally submitted to COGCC in 2010 and later
in regards to a Pad Expansion Application in 2013.
In review of these documents it is my determination that the existing pad and access road
grading conform to the construction plans as submitted.
February 18, 2014
Mr. Scott Aibner
River Valley Survey
email: saibner@comcast.net
CRUX
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Coll\SultCI ""'ts
RE: Speakman A Pao -COGCC Grading Review Letter
Dear Scott:
The CRUx Consulting Group, Inc. has completed a grading compliance review for the
Speakman A Pad proposed small injection well Garfield County Administrative Review land use
permit. This review was conducted to review the original 2010 and amended 2013 grading plan
submitted to the COG CC for the construction of the gas pad in regards to general engineering
standards and practices. From the review we have performed, the design as submitted to the
COGCC appears to meet general engineering standards for the design of the pad grading and
access roadway.
It is our understanding the pad was constructed with the stormwater/erosion control elements
as depicted on the plans, and that the project has gone through a period of final stabilization. It
is our recommendation that the site be reviewed with Steve Anthony of Garfield County to
confirm final stabilization and revegetation was achieved to the satisfactory level required by
Garfield County. If you have any questions please do not hesitate to call me directly at
970.319.9744,
CRUx Consulting Group
110 E. 3'd Street Suite 204 I Rifle, Colorado 81650
970.319.9744 (o/c)
CRUX
cl.vl.L 6""01.111..uri.""0 § t::>eveLop~e111..t
Co111..Si.<.Lt&1111..ts
The installation of a small injection well will not require grading improvements to the site. No
increase in runoff is anticipated for this construction.
Detention/Storm Water Quality/Erosion Control
Due to the low imperviousness of the historic and existing basins, and.the reduced tributary
basin size of the gas pad development, no 25 -year event detention is required for the site.
Construction best management practices for the protection of water quality and flows released
offsite were provided to the COGCC as part of the application submittal. The review
documentation provided to us shows a measure of pipe outlet and inlet protection, silt fence
and straw waddle proposed for the construction of the pad. These are typical with grading
construction associated with oil & gas pads in Garfield County. It is our understanding that this
pad has gone through the construction and final stabilization process for the storm water
permitting process and no further storm water control is necessary, and the pad is currently
operating under guidelines established by URSA for spill containment and incident isolation.
The proposed construction will require proper best management practices for construction
within the oil & gas industry. It is our recommendation that the erosion control measures
included on the grading and drainage plan be incorporated, which include silt fence and
temporary diversion dykes to a settling basin for potential spill containment. The temporary
settling basin recommendation provides no hydrological benefit and is not sized based on
hydrological informati on, but rather a secondary support system to the spill containment plan.
Conclusion
This storm drainage analysis reviewed historic and existing conditions, calculated estimated
storm water runoff consistent with the requirements of Garfield County and indicates that the
design approach is feasible and meets standard engi neering guidelines. Due to the low runoff of
the historic and existing conditions, no detention is required for the site. The storm water
management has been conducted by other through final stabilization, but appears based on the
information presented, to be in general conformance to good practices typical of the oil & gas
industry. The project is not located in the 100-year floodplain.
CRUx Consulting Group
110 E. 3'd Street Suite 204 I Rifle, Colorado 81650
970.319.9744 (o/c)
CRU XX
Civil Engineering & Development
Consultants
CRUx
Consulting
Group
110
E.
3rd
Street
Suite
204
│Rifle,
Colorado
81650
970.319.9744
(o/c)
February
18,
2014
Mr.
Scott
Aibner
River
Valley
Survey
email:
saibner@comcast.net
RE:
Speakman
A
Pan
–
Drainage
Review
Letter
Dear
Scott:
The
CRU XX
Consulting
Group,
Inc.
has
completed
a
drainage
review
for
the
Speakman
A
Pad
proposed
small
injection
well
Garfield
County
Administrative
Review
land
use
permit.
This
review
is
being
submitted
to
satisfy
the
Garfield
County
Regulatory
Requirements
outlined
in
section
4-‐203
(E)
of
the
Garfield
County
Land
Use
and
Development
Code.
The
project
is
unique
in
that
no
proposed
surface
improvements
are
being
completed
for
the
small
injection
well
application
that
will
alter
or
change
the
existing
gas
pad
site
grading
or
drainage.
However,
because
Garfield
County
did
not
formally
review
and
approve
the
gas
pad
(constructed
under
the
guidelines
of
the
COGCC),
the
site
is
being
evaluated
for
grading
and
drainage
impacts
the
development
of
the
gas
pad
pay
have
had
at
the
time
of
construction,
and
any
proposed
improvements
that
may
be
necessary
to
be
in
compliance
with
the
requirements
of
Garfield
County.
The
purpose
of
this
drainage
letter
is
to
review
the
“Historic”,
as
defined
for
purposes
of
this
letter
as
pre-‐gas
pad
development,
and
the
“Existing”,
as
defined
as
post
gas
pad
development.
Methodology
The
peak
runoff
flows
for
the
analysis
were
determined
using
the
Rational
Method.
The
Urban
Drainage
Flood
Control
District
(UDFCD)
Rational
Method
spreadsheets
were
utilized
to
calculate
design
flows.
Design
criteria
established
by
Garfield
County
require
that
the
peak
discharge
rate
does
not
exceed
the
Historic
peak
rate
for
the
2
year
and
25
year
storm
events.
The
County
also
requires
that
storm
water
detention
facilities
(if
required)
must
demonstrate
that
there
is
safe
passage
of
the
100
year
event
without
causing
property
damage.
Based
on
the
NOAA
Atlas
2,
Volume
3
precipitation
maps
that
cover
the
project
area
the
1-‐Hour
rainfall
for
the
2
year,
25
year
and
100
year
24
hour
precipitation
events
were
estimated
to
be
0.56,
1.10
and
1.43
inches
per
hour
respectively.
CRU XX
Civil Engineering & Development
Consultants
CRUx
Consulting
Group
110
E.
3rd
Street
Suite
204
│Rifle,
Colorado
81650
970.319.9744
(o/c)
The
type
of
ground
cover
and
soils
affects
the
runoff
volume
from
a
site.
The
USDS
NRCS
Web
Soil
Survey
was
utilized
to
determine
the
soils
data.
The
survey
determined
the
primary
majority
soil
type
within
the
limits
of
the
project
is
56-‐Potts
Loam
with
a
hydrologic
soil
group
rating
of
“C”
indicative
of
slow
rate
of
water
infiltration.
Runoff
coefficient
numbers
were
calculated
in
the
Rational
Method
Spreadsheets
and
are
determined
based
on
the
impervious
area
within
each
basin.
The
travel
lengths
and
time
of
concentration
were
also
calculated
in
the
spreadsheets
and
based
upon
overland
flow,
shallow
concentrated
flow
and
channelized
flow
characteristics.
Historic
Conditions
The
existing
topography
of
the
“Historic”
site,
before
the
gas
pad
was
installed,
drained
in
general
from
south
to
the
northeast
corner
joining
flows
within
a
large
gulch.
The
site
had
several
constraints,
which
limited
the
runoff
potential.
A
steep
ridgeline
separated
the
site
from
the
Private
Road
“Daybreak
Drive”
on
the
west
and
property
to
the
north,
and
a
large
ravine
was
located
adjacent
to
the
eastern
property
boundary.
Several
vehicle
trails
and
primitive
roadways
had
been
constructed
that
entered
the
property
from
the
northeast,
The
reviewed
historic
property
resulted
in
a
tributary
basin
approximately
9.85
acres
in
size,
with
sage
brush
and
sparse
vegetation
indicative
of
the
western
Garfield
County
region.
Information
on
the
historic
property
was
gathered
through
the
original
survey
data
and
COGCC
submittal
that
contained
photo
documentation
pre-‐disturbance.
Historic
storm
water
flows
were
calculated
using
a
historic
imperviousness
of
2%
and
yielded
a
Q2/Q25
=
0.59/7.99
cfs
at
a
design
point
at
the
northeast
side
of
the
property.
Existing
Conditions
In
2010,
development
of
the
gas
pad
for
extraction
altered
the
site,
however
many
of
the
historic
constraints
remained.
The
pad
site
remained
bound
on
the
west
and
north
by
the
ridgeline
separating
it
from
the
Private
Road
“Daybreak
Drive”,
and
situated
a
flat
rectangular
pad
between
the
ridgeline
and
the
gulch
to
the
east.
In
2013
the
pad
was
expanded
southerly
approximately
100-‐ft
but
did
not
change
the
pad
characteristics
or
storm
water
flow
patterns.
The
pad
connected
to
Daybreak
Drive
to
the
south
via
a
private
access
road
that
was
installed
with
the
pad.
The
main
tributary
basin
was
reduced
to
approximately
6.48
acres
in
size,
and
the
existing
storm
water
flows
were
determined
to
be
Q2/Q25
=
0.52/5.21
cfs.
An
imperviousness
of
5%
was
utilized
in
the
calculations
to
accommodate
barrels
and
pipe
improvements
located
on
the
gas
well
site.
APPENDIX
A
Hydrologic
Data
NRCS
Soils
Information
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = H1
Area = 9.85 Acres
Percent Imperviousness = 2.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 2 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 0.56 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.06
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.16
Overide 5-yr. Runoff Coefficient, C =(enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations:Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0600 300 0.16 N/A 0.31 16.22
1 0.1500 789 8.00 3.10 4.24
2 8.00
3 8.00
4
5
1,089 Computed Tc=20.46
Regional Tc = 16.05
User-Entered Tc = 16.05
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I =1.09 inch/hr Peak Flowrate, Qp = 0.59 cfs
Rainfall Intensity at Regional Tc, I =1.23 inch/hr Peak Flowrate, Qp = 0.67 cfs
Rainfall Intensity at User-Defined Tc, I =1.23 inch/hr Peak Flowrate, Qp = 0.67 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Speak A Pad Drainage
Historic -2 Year
Paved Areas &
Speakman Historic.xls, Tc and PeakQ 2/19/2014, 1:21 PM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = H1
Area = 9.85 Acres
Percent Imperviousness = 2.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 25 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.10 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.38
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.16
Overide 5-yr. Runoff Coefficient, C =(enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations:Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0600 300 0.16 N/A 0.31 16.22
1 0.1500 789 8.00 3.10 4.24
2 8.00
3 8.00
4
5
1,089 Computed Tc=20.46
Regional Tc = 16.05
User-Entered Tc = 16.05
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I =2.14 inch/hr Peak Flowrate, Qp = 7.99 cfs
Rainfall Intensity at Regional Tc, I =2.42 inch/hr Peak Flowrate, Qp = 9.04 cfs
Rainfall Intensity at User-Defined Tc, I =2.42 inch/hr Peak Flowrate, Qp = 9.04 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Speak A Pad Drainage
Historic -25 Year
Paved Areas &
Speakman Historic.xls, Tc and PeakQ 2/19/2014, 1:20 PM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = EX
Area = 6.48 Acres
Percent Imperviousness = 5.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 2 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 0.56 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.08
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.18
Overide 5-yr. Runoff Coefficient, C =(enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations:Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0560 300 0.18 N/A 0.31 16.26
1 0.0850 145 8.00 2.33 1.04
2 0.0640 462 8.00 2.02 3.80
3 0.1500 204 8.00 3.10 1.10
4
5
1,111 Computed Tc=22.20
Regional Tc = 16.17
User-Entered Tc = 16.17
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I =1.04 inch/hr Peak Flowrate, Qp = 0.52 cfs
Rainfall Intensity at Regional Tc, I =1.23 inch/hr Peak Flowrate, Qp = 0.61 cfs
Rainfall Intensity at User-Defined Tc, I =1.23 inch/hr Peak Flowrate, Qp = 0.61 cfs
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Speakman A Pad Drainage
Existing 2 year
Paved Areas &
(Sheet Flow)
20
Shallow Paved Swales
Sum
Speakman Existing.xls, Tc and PeakQ 2/19/2014, 1:26 PM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = EX
Area = 6.48 Acres
Percent Imperviousness = 5.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 25 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.10 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.39
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.18
Overide 5-yr. Runoff Coefficient, C =(enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations:Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0560 300 0.18 N/A 0.31 16.26
1 0.0850 145 8.00 2.33 1.04
2 0.0640 462 8.00 2.02 3.80
3 0.1500 204 8.00 3.10 1.10
4
5
1,111 Computed Tc=22.20
Regional Tc = 16.17
User-Entered Tc = 16.17
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I =2.05 inch/hr Peak Flowrate, Qp = 5.21 cfs
Rainfall Intensity at Regional Tc, I =2.41 inch/hr Peak Flowrate, Qp = 6.13 cfs
Rainfall Intensity at User-Defined Tc, I =2.41 inch/hr Peak Flowrate, Qp = 6.13 cfs
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Speakman A Pad Drainage
Existing 25 year
Paved Areas &
(Sheet Flow)
20
Shallow Paved Swales
Sum
Speakman Existing.xls, Tc and PeakQ 2/19/2014, 1:27 PM
United States
Department of
Agriculture
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
Rifle Area, Colorado,
Parts of Garfield and
Mesa Counties
Speakman A Pad
Natural
Resources
Conservation
Service
February 19, 2014
Preface
Soil surveys contain information that affects land use planning in survey areas. They
highlight soil limitations that affect various land uses and provide information about
the properties of the soils in the survey areas. Soil surveys are designed for many
different users, including farmers, ranchers, foresters, agronomists, urban planners,
community officials, engineers, developers, builders, and home buyers. Also,
conservationists, teachers, students, and specialists in recreation, waste disposal,
and pollution control can use the surveys to help them understand, protect, or enhance
the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil properties
that are used in making various land use or land treatment decisions. The information
is intended to help the land users identify and reduce the effects of soil limitations on
various land uses. The landowner or user is responsible for identifying and complying
with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some cases.
Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/portal/
nrcs/main/soils/health/) and certain conservation and engineering applications. For
more detailed information, contact your local USDA Service Center (http://
offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil
Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?
cid=nrcs142p2_053951).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic
tank absorption fields. A high water table makes a soil poorly suited to basements or
underground installations.
The National Cooperative Soil Survey is a joint effort of the United States Department
of Agriculture and other Federal agencies, State agencies including the Agricultural
Experiment Stations, and local agencies. The Natural Resources Conservation
Service (NRCS) has leadership for the Federal part of the National Cooperative Soil
Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs
and activities on the basis of race, color, national origin, age, disability, and where
applicable, sex, marital status, familial status, parental status, religion, sexual
orientation, genetic information, political beliefs, reprisal, or because all or a part of an
individual's income is derived from any public assistance program. (Not all prohibited
bases apply to all programs.) Persons with disabilities who require alternative means
2
for communication of program information (Braille, large print, audiotape, etc.) should
contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a
complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400
Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272
(voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and
employer.
3
Contents
Preface....................................................................................................................2
Soil Map..................................................................................................................5
Soil Map................................................................................................................6
Legend..................................................................................................................7
Map Unit Legend..................................................................................................8
Map Unit Descriptions..........................................................................................8
Rifle Area, Colorado, Parts of Garfield and Mesa Counties............................10
56—Potts loam, 6 to 12 percent slopes......................................................10
58—Potts-Ildefonso complex, 12 to 25 percent slopes...............................10
References............................................................................................................13
4
Soil Map
The soil map section includes the soil map for the defined area of interest, a list of soil
map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
5
6
Custom Soil Resource Report
Soil Map
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752880 752920 752960 753000 753040 753080 753120 753160 753200 753240
752880 752920 752960 753000 753040 753080 753120 753160 753200 753240
39° 25' 18'' N
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39° 25' 18'' N
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N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 12N WGS84
0 50 100 200 300
Feet
0 25 50 100 150
Meters
Map Scale: 1:1,730 if printed on A landscape (11" x 8.5") sheet.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more accurate
calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa
Counties
Survey Area Data: Version 7, Dec 23, 2013
Soil map units are labeled (as space allows) for map scales 1:50,000
or larger.
Date(s) aerial images were photographed: Jun 22, 2010—Sep 3,
2011
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
7
Map Unit Legend
Rifle Area, Colorado, Parts of Garfield and Mesa Counties (CO683)
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
56 Potts loam, 6 to 12 percent
slopes
4.8 72.7%
58 Potts-Ildefonso complex, 12 to
25 percent slopes
1.8 27.3%
Totals for Area of Interest 6.6 100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the soils
or miscellaneous areas in the survey area. The map unit descriptions, along with the
maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the landscape,
however, the soils are natural phenomena, and they have the characteristic variability
of all natural phenomena. Thus, the range of some observed properties may extend
beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic
class rarely, if ever, can be mapped without including areas of other taxonomic
classes. Consequently, every map unit is made up of the soils or miscellaneous areas
for which it is named and some minor components that belong to taxonomic classes
other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They generally
are in small areas and could not be mapped separately because of the scale used.
Some small areas of strongly contrasting soils or miscellaneous areas are identified
by a special symbol on the maps. If included in the database for a given area, the
contrasting minor components are identified in the map unit descriptions along with
some characteristics of each. A few areas of minor components may not have been
observed, and consequently they are not mentioned in the descriptions, especially
where the pattern was so complex that it was impractical to make enough observations
to identify all the soils and miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the usefulness
or accuracy of the data. The objective of mapping is not to delineate pure taxonomic
classes but rather to separate the landscape into landforms or landform segments that
have similar use and management requirements. The delineation of such segments
on the map provides sufficient information for the development of resource plans. If
Custom Soil Resource Report
8
intensive use of small areas is planned, however, onsite investigation is needed to
define and locate the soils and miscellaneous areas.
An identifying symbol precedes the map unit name in the map unit descriptions. Each
description includes general facts about the unit and gives important soil properties
and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major horizons
that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity,
degree of erosion, and other characteristics that affect their use. On the basis of such
differences, a soil series is divided into soil phases. Most of the areas shown on the
detailed soil maps are phases of soil series. The name of a soil phase commonly
indicates a feature that affects use or management. For example, Alpha silt loam, 0
to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps. The
pattern and proportion of the soils or miscellaneous areas are somewhat similar in all
areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present or
anticipated uses of the map units in the survey area, it was not considered practical
or necessary to map the soils or miscellaneous areas separately. The pattern and
relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-
Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas that
could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion of
the soils or miscellaneous areas in a mapped area are not uniform. An area can be
made up of only one of the major soils or miscellaneous areas, or it can be made up
of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil material
and support little or no vegetation. Rock outcrop is an example.
Custom Soil Resource Report
9
Rifle Area, Colorado, Parts of Garfield and Mesa Counties
56—Potts loam, 6 to 12 percent slopes
Map Unit Setting
Elevation:5,000 to 7,000 feet
Map Unit Composition
Potts and similar soils:85 percent
Description of Potts
Setting
Landform:Benches, mesas, valley sides
Down-slope shape:Linear, convex
Across-slope shape:Linear, convex
Parent material:Alluvium derived from basalt and/or alluvium derived from
sandstone and shale
Properties and qualities
Slope:6 to 12 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water (Ksat):Moderately high (0.20 to
0.60 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:15 percent
Maximum salinity:Nonsaline (0.0 to 2.0 mmhos/cm)
Available water capacity:High (about 10.3 inches)
Interpretive groups
Farmland classification:Farmland of statewide importance
Land capability classification (irrigated):4e
Land capability (nonirrigated):4e
Hydrologic Soil Group:C
Ecological site:Rolling Loam (R048AY298CO)
Typical profile
0 to 4 inches:Loam
4 to 28 inches:Clay loam
28 to 60 inches:Loam
58—Potts-Ildefonso complex, 12 to 25 percent slopes
Map Unit Setting
Elevation:5,000 to 6,500 feet
Map Unit Composition
Potts and similar soils:60 percent
Custom Soil Resource Report
10
Ildefonso and similar soils:30 percent
Description of Potts
Setting
Landform:Mesas, alluvial fans, valley sides
Down-slope shape:Convex, linear
Across-slope shape:Convex, linear
Parent material:Alluvium derived from basalt and/or alluvium derived from
sandstone and shale
Properties and qualities
Slope:12 to 25 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water (Ksat):Moderately high (0.20 to
0.60 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:15 percent
Maximum salinity:Nonsaline (0.0 to 2.0 mmhos/cm)
Available water capacity:High (about 10.3 inches)
Interpretive groups
Farmland classification:Not prime farmland
Land capability (nonirrigated):6e
Hydrologic Soil Group:C
Ecological site:Rolling Loam (R048AY298CO)
Typical profile
0 to 4 inches:Loam
4 to 28 inches:Clay loam
28 to 60 inches:Loam
Description of Ildefonso
Setting
Landform:Valley sides, mesas, alluvial fans
Down-slope shape:Convex
Across-slope shape:Convex
Parent material:Alluvium derived from basalt and/or alluvium derived from
sandstone and shale
Properties and qualities
Slope:12 to 25 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high
(0.60 to 6.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:35 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 4.0 mmhos/cm)
Available water capacity:Low (about 5.1 inches)
Custom Soil Resource Report
11
Interpretive groups
Farmland classification:Not prime farmland
Land capability (nonirrigated):6e
Hydrologic Soil Group:A
Typical profile
0 to 8 inches:Stony loam
8 to 60 inches:Very stony loam
Custom Soil Resource Report
12
References
American Association of State Highway and Transportation Officials (AASHTO). 2004.
Standard specifications for transportation materials and methods of sampling and
testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service
FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils
in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S.
Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/nrcs/
detail/national/soils/?cid=nrcs142p2_054262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making
and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service,
U.S. Department of Agriculture Handbook 436. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/national/soils/?cid=nrcs142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://www.nrcs.usda.gov/wps/
portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/main/national/
landuse/forestry/pub/
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/
detail/national/landuse/rangepasture/?cid=stelprdb1043084
13
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/soils/scientists/?cid=nrcs142p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States, the
Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296.
http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?
cid=nrcs142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http://
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf
Custom Soil Resource Report
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These drawings have been prepared for theclient identified on the design sheet titleblock.Unless these drawings bear a signed engineersseal, they may be used only at owners sole risk.
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1
0GRAPHIC SCALE IN FEET 505010025
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = H1
Area = 7.72 Acres
Percent Imperviousness = 2.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 25 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.10 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.38
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.16
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy T illage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations:Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0600 300 0.16 N/A 0.31 16.22
1 0.1500 789 8.00 3.10 4.24
2 8.00
3 8.00
4
5
1,089 Computed Tc =20.46
Regional Tc = 16.05
User-Entered Tc = 16.05
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I =2.14 inch/hr Peak Flowrate, Qp = 6.27 cfs
Rainfall Intensity at Regional Tc, I =2.42 inch/hr Peak Flowrate, Qp = 7.08 cfs
Rainfall Intensity at User-Defined Tc, I =2.42 inch/hr Peak Flowrate, Qp = 7.08 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Speak A Pad Drainage
Historic -25 Year
Paved Areas &
Speakman Historic, Tc and PeakQ 6/19/2014, 1:59 PM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = EX1
Area = 6.40 Acres
Percent Imperviousness = 5.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 25 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.10 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.39
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.18
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy T illage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations:Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0560 300 0.18 N/A 0.31 16.26
1 0.0850 145 8.00 2.33 1.04
2 0.0640 462 8.00 2.02 3.80
3 0.1500 204 8.00 3.10 1.10
4
5
1,111 Computed Tc =22.20
Regional Tc = 16.17
User-Entered Tc = 16.17
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I =2.05 inch/hr Peak Flowrate, Qp = 5.15 cfs
Rainfall Intensity at Regional Tc, I =2.41 inch/hr Peak Flowrate, Qp = 6.06 cfs
Rainfall Intensity at User-Defined Tc, I =2.41 inch/hr Peak Flowrate, Qp = 6.06 cfs
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Speakman A Pad Drainage
Existing-1 25 year
Paved Areas &
(Sheet Flow)
20
Shallow Paved Swales
Speakman Existing, Tc and PeakQ 6/19/2014, 1:46 PM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = EX
Area = 1.73 Acres
Percent Imperviousness = 2.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 25 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.10 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.38
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.16
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy T illage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations:Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0730 273 0.16 N/A 0.31 14.50
1 0.0250 154 8.00 1.26 2.03
2 0.3500 142 9.00 5.32 0.44
3
4
5
569 Computed Tc =16.98
Regional Tc = 13.16
User-Entered Tc = 13.16
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I =2.35 inch/hr Peak Flowrate, Qp = 1.54 cfs
Rainfall Intensity at Regional Tc, I =2.65 inch/hr Peak Flowrate, Qp = 1.74 cfs
Rainfall Intensity at User-Defined Tc, I =2.65 inch/hr Peak Flowrate, Qp = 1.74 cfs
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Speakman A Pad Drainage
Existing 2 25 year
Paved Areas &
(Sheet Flow)
20
Shallow Paved Swales
Speakman Existing, Tc and PeakQ 6/19/2014, 2:05 PM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = EX
Area = 8.13 Acres
Percent Imperviousness = 4.40 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 25 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.10 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.39
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.18
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy T illage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations:Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0560 300 0.18 N/A 0.31 16.33
1 0.0850 145 8.00 2.33 1.04
2 0.0640 462 8.00 2.02 3.80
3 0.1500 204 8.00 3.10 1.10
4
5
1,111 Computed Tc =22.26
Regional Tc = 16.17
User-Entered Tc = 16.17
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I =2.04 inch/hr Peak Flowrate, Qp = 6.48 cfs
Rainfall Intensity at Regional Tc, I =2.41 inch/hr Peak Flowrate, Qp = 7.64 cfs
Rainfall Intensity at User-Defined Tc, I =2.41 inch/hr Peak Flowrate, Qp = 7.64 cfs
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Speakman A Pad Drainage
Existing Overall 25 year
Paved Areas &
(Sheet Flow)
20
Shallow Paved Swales
Speakman Existing, Tc and PeakQ 6/20/2014, 12:09 PM
""""
T:\CLIENTS\URSA\BATTLEMENT MESA\SPEAKMAN A\SPEAKMAN\Speakman A Stormwater 4-1-15 REV 1 4-13-15.mxd
±
0 100 200Feet
Author: E. Fought
Revision: 1
Stormwater Site MapStormwater Site MapSpeakman A
39.420827 -108.060354Section 24, Township 7 South, Range 96 West
Pad Disturbance Area: 4.2 acres
Acres Reclaimed: 2.0 acres
Production/Operation Surface: 2.2 acres
Date: 4/13/2015
Stormwater BMPs
NOTES / COMMENTS:
0 1Miles
Sediment Trap""
Earthen Berm
Rip Rap / Armoring
Diversion Ditch
Top Soil Stockpile
Area of Disturbance
Appendix F - Site Specific Stormwater
Management Plan
Project Name (Site): Speakman A Well Pad Field Name: Battlement Mesa
Latitude: 39.420663° Longitude: -108.056968°
CDPS Permit Number: COR03K566 Inspection Type: 14 Day
Phase: Temporary
Name of Receiving Water: Dry Creek, Ultimately the Colorado River
Estimated Distance to Receiving Water: 0.41 miles, 0.5 miles respectively
Twp, Sec, Range: T-7-S R-96-W, Section 24 SW ¼
Major Erosion Control Facilities/Structures (BMPs) Utilized at Site: Vegetative Buffer,
Diversion Ditch, Berm, Sediment Trap.
Estimate of Total Area of Site: 8.7 acres Estimate of Reclaimed Acres of Site: TBD
Soil Types: Potts Loam (6 to 12% slopes) Permeability: Moderate to rapid
Soil Erosion Potential: Moderate to severe
Existing Vegetation Description: Wheat grass, needle and thread, and sagebrush
Final Stabilization Date: TBD
Estimate of Percent Vegetative Ground Cover: 60%
Seed Mix for Interim Final Reclamation: Ursa Dryland Pasture Seed Mix or Landowner Seed
Mix
Description of Non-SW Discharge Components (e.g., Springs, Irrigation): None
Location of Non-SW Discharge Components (e.g., Springs, Irrigation): None
Phased BMPs
Construction:
Top soil will be utilized as a berm around the north and east sides of the location.
Two sediment ponds will be installed on the northeast corner of location.
Spill ways will be armored with riprap.
Berm/diversion ditch will direct water along the east and north sides of location into the
sediment traps.
Top soil will be stockpiled on the south side of the location to prevent run-on and erosion
of the cut slope.
Gravel will be applied to the pad’s surface as final grade.
Portable lavatories will be staked down.
Post Construction:
Upon completion of pad construction, temporary stormwater structures that are no longer
a viable BMP will be removed.
All permanent BMPs installed during construction phase will remain on site for the life-
time of the pad.
Monitoring:
Inspections will occur every 14 days and after a significant precipitation event.
Inspections will be conducted by a certified person familiar with the site specific control
measures and COAs of the pad.
Inspections will cover the following:
o Disturbed area;
o All BMPs, temporary and permanent;
o Materials storage areas;
o Down gradient areas;
o Surface water diversions;
o Access road; and
o Pad entrance.
Maintenance Procedures:
Maintenance will include prompt repairs and/or adjustments to any erosion and sediment control
structures that are deteriorating or found to be performing inadequately. BMP conditions and
dates of BMP maintenance will be documented within the stormwater inspection checklists.
Comments: The Speakman A well pad is currently in the temporary phase. Site will remain in
temporary phase until drilling operations have been completed. The project will enter into
interim reclamation when the temporary interim phase is completed. Temporary BMPs that were
implemented during the construction phase may continue to be maintained during temporary
interim and interim reclamation. Project will remain in interim reclamation until disturbed areas
have been reclaimed to 70% of pre-disturbance conditions or otherwise permanently stabilized
(i.e. graveled).
Amended 6/8/15