HomeMy WebLinkAboutTHE LEARNING EXPERIENCE @ MIRAMONT OFFICE PARK - PDP - PDP130023 - REPORTS - STORMWATER MANAGEMENT PLANStormwater Management Plan
(SWMP)
The Learning Experience at Miramont Office Park
Prepared for:
Adam Rubenstein
Rubenstein Real Estate Company
C/O The Legend Retail Group
5150 E. Yale Circle, Suite 400
Denver, CO 80222
720-529-2881
arubenstein@legendretailgroup.com
Prepared by:
Contact: Mark D. Cevaal, P.E.
mcevaal@redland.com
October 4, 2013
Project No. 12026
Stormwater Management Plan The Learning Experience at Miramont Office Park
1
STORMWATER MANAGEMENT PLAN
FOR
THE LEARNING EXPERIENCE AT MIRAMONT OFFICE PARK
FORT COLLINS, COLORADO
TABLE OF CONTENTS Page
1. INTRODUCTION ............................................................................................................ 2
2. SITE DESCRIPTION ...................................................................................................... 2
A. Description of the Site .................................................................................. 2
B. SWMP Administrator .................................................................................... 3
C. Proposed Sequence for Major Construction Activities .................................. 3
D. Area Estimates ............................................................................................. 4
E. Soils .............................................................................................................. 4
F. Runoff Coefficients ....................................................................................... 5
G. Existing Vegetation ....................................................................................... 5
H. Potential Pollution Sources ........................................................................... 5
I. Non-Stormwater Discharge Components ..................................................... 5
J. Outfall and Receiving Waters ....................................................................... 6
3. SITE MAP ..................................................................................................................... 7
4. BMPS FOR STORMWATER POLLUTION PREVENTION ............................................ 7
A. Administrative Controls ................................................................................. 7
B. Erosion and Sediment Controls .................................................................... 7
C. Materials Handling and Spill Prevention ....................................................... 9
5. FINAL STABILIZATION AND LONG-TERM STORMWATER MANAGEMENT .............10
6. INSPECTION AND MAINTENANCE ............................................................................10
7. CDPS GENERAL PERMIT ............................................................................................11
8. SECURITY FOR EROSION CONTROL ........................................................................11
9. REFERENCES ..............................................................................................................12
APPENDIX 1 – Vicinity Map
APPENDIX 2 – Soil Report .........................................................................
APPENDIX 3 – Erosion Control Cost Estimate
APPENDIX 4 – BMP Sequencing Chart
APPENDIX 5 – BMP Details
APPENDIX 6 - Erosion Control Plans
Stormwater Management Plan The Learning Experience at Miramont Office Park
2
STORMWATER MANAGEMENT PLAN
FOR
THE LEARNING EXPERIENCE AT MIRAMONT OFFICE PARK
FORT COLLINS, COLORADO
1. INTRODUCTION
The purpose of this Stormwater Management Plan (SWMP) is to develop a
comprehensive stormwater/erosion control plan for The Learning Experience at
Miramont Office Park.
2. SITE DESCRIPTION
A. Description of the Site
The construction activities covered in this SWMP include earthwork, building
construction, utility construction, paving, landscaping, and other work required to
complete the proposed Site. The major construction activities that may impact
stormwater runoff include overlot grading, final grading, building construction and
installation of utilities.
It is the intent of this SWMP to implement best management practices (BMP) for
enhancing the quality of stormwater discharges associated with the construction
activity. BMP designs are based on the criteria set forth in the Fort Collins
Stormwater Criteria Manual.
The portion of the Site that will be disturbed is approximately 0.7-acres in the
northeast quarter of Section 1, Township 6 North, Range 69 West of the 6th
Principal Meridian in the City of Fort Collins, Larimer County, State of Colorado.
More specifically, the Site is located at the northwest corner of South Boardwalk
Drive and Oakridge Drive on Lot 3 of Miramont Office Park Plat. A vicinity map is
included in Appendix 1.
The project is bounded by a retail center to the east, a self-storage area to the
south, a church to the west and offices to the north. Surrounding areas of the Site
are mostly developed with single family homes with intermittent commercial,
retail and institutional uses.
The Site contains a detention pond that collects runoff from the existing office
development. The building will be placed within a portion of the existing
detention facility, requiring the pond to be modified. During construction, this
area will be disturbed and will be a potential pollutant source.
The Site is currently developed as a parking lot, building pad and detention pond.
The Site and properties directly adjacent are not in a floodplain as designated by
FEMA.
Stormwater Management Plan The Learning Experience at Miramont Office Park
3
Primary access for the Site will be via Boardwalk Drive and Oakridge Drive.
The Learning Experience at Miramont will be completed in a single phase.
B. SWMP Administrator
The SWMP Administrator shall be the General Contractor. Contact information
of the responsible individual shall be available prior to land disturbance.
C. Proposed Sequence for Major Construction Activities
The expected sequence of activities is to be as follows:
i. Overlot Grading (March 2014)
This phase includes installation of erosion control devices, construction of
stormwater management facilities including overlot grading to include
excavation and placement of material.
The BMP’s to be installed during overlot grading include: silt fence,
sediment control logs, inlet protection, curb rock socks, vehicle tracking
control system, construction fence and a staging area.
ii. Utility Installation (March 2014 - May 2014)
This phase includes storm sewer, sanitary sewer, water line and dry utility
installation:
• Sanitary Sewer (April 2014)
This phase will include the sanitary sewer service for the building.
All existing BMP’s will be maintained and replaced when
necessary.
• Storm Sewer & Drainage Facility Construction (March - May 2014)
This phase will include all site storm sewer, water quality and
stormwater detention pond including retaining walls. The BMP’s
to be installed during storm sewer and drainage facility
construction include: concrete washout. All existing BMP’s will be
maintained and replaced when necessary.
Stormwater Management Plan The Learning Experience at Miramont Office Park
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• Water Lines (April 2014)
This phase will include the installation of all water mains and water
service for the building. All existing BMP’s will be maintained and
replaced when necessary.
• Dry Utilities (March 2014)
This phase will include all dry utility work for the building. All
existing BMP’s will be maintained and replaced when necessary.
iii. Building Construction (April 2014 – August 2014)
This phase will include the construction of the piers/foundation, building
walls and entry-ways. All existing BMP’s will be maintained and replaced
when necessary.
iv. Site Improvements (July 2014 – August 2014)
This phase includes final grading, irrigation, landscaping, curb and gutter,
sidewalk, lighting, signage and paving. Vehicle Tracking BMP will be
removed to allow for final grading and landscaping. All other existing
BMP’s will be maintained and replaced when necessary.
v. Final Closeout (August 2014 – September 2014)
All remaining BMP’s shall be removed.
See Appendix 4 for the BMP Sequencing Chart.
D. Area Estimates
Lot 3 of the Miramont Office Park is 1.614 acres. 0.84 acres will be disturbed
during construction.
E. Soils
The undeveloped portions of Lot 3 are covered in native weeds and grasses. The
site has relatively mild grades (<2%) and no major drainageways cross the site.
The soils on-site are Nunn Clay Loam which is a Type C soil according the
NRCS Soil Survey. Type C soils have slow infiltration rates when wet and have a
slow rate of water transmission. Please see Appendix 2 for a detailed soil
report. Runoff from the site will be conveyed to the existing stormwater detention
facility located in the southwest corner of the site.
The entire site has an erosion factor, K, rating of 0.20. Please see Appendix 2
for details of the erodibility of the soil.
Stormwater Management Plan The Learning Experience at Miramont Office Park
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F. Runoff Coefficients
During the construction of the Site improvements, the runoff coefficients are
expected to range from 0.28 for disturbed areas or bare soil and temporarily
seeded areas to 0.95 for paved areas. After construction is complete, the
average runoff coefficients are expected to range between 0.28 and 0.95.
G. Existing Vegetation
Currently, the Site consists of existing parking lot, turf and natural grasses.
H. Potential Pollution Sources
Below is a list of possible pollution sources produced during the construction
phase:
• All disturbed and stored soils
• Vehicle and equipment fueling and maintenance
• Concrete wash-outs, management of contaminated soils
• Loading and unloading operations
• Vehicle tracking pads
• Significant dust or particulate generating processes
• On-site waste management practices (waste piles, liquid wastes,
dumpsters, etc.)
• Outdoor storage activities (fertilizer, chemicals, building materials, etc.)
• Portable toilets or worker trash
• Chemical handling
• Stockpile areas
I. Non-Stormwater Discharge Components
Only specifically authorized non-stormwater discharges are allowed and all
allowed non-stormwater discharges shall be eliminated or reduced to the extent
practicable.
The following non-stormwater discharges are allowable under the Colorado
Department of Public Health and Environment CDPS General Permit and are
possible to be associated with the project:
Stormwater Management Plan The Learning Experience at Miramont Office Park
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• Discharge from emergency fire - fighting activities;
• Uncontaminated ground water or spring water;
• Landscape irrigation;
Appropriate BMPs shall be used to minimize the discharge of pollutants. Such
control measures (some of which have been mentioned previously in this SWMP)
will be strictly followed to ensure any impacts from non-stormwater discharges
are reduced or eliminated. Appropriate BMPs are:
i. Uncontaminated ground water or spring water
If possible direct uncontaminated ground water or spring water to
stabilized points of discharge. If discharged to disturbed area, assure
measures to control erosive velocities and sediment control measures are
implemented. Velocity control measures include riprap aprons and other
conveyance measures. Sediment control measures might include stone
check dams, sediment traps and basins.
Foundation or footing drains where flows are not contaminated with
process materials such as solvents. If possible, direct foundation or
footing drain flows to stabilized points of discharge. If discharged to
disturbed area, assure measures to control erosive velocities and
sediment control measures are implemented. Velocity control measures
include riprap aprons and other conveyance measures. Sediment control
measures might include stone check dams, sediment traps and basins.
ii. Landscape Irrigation
Volume of water used for irrigation prior to establishment of vegetation
shall be controlled to prevent excess runoff and erosion. Temporary
sediment control measures shall remain in place until all upstream
disturbed areas are stabilized. Sediment loss will be controlled through
the use of sediment control measures such as wattles, sediment fence,
and vegetative buffers.
J. Outfall and Receiving Waters
The site is located in the McClellands Creek Basin and the receiving waters in
this basin is McClellands Creek.
Stormwater Management Plan The Learning Experience at Miramont Office Park
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3. SITE MAP
Limits of disturbance are shown on the Erosion Control Plans included in a pocket
located in the Appendix.
4. BMPS FOR STORMWATER POLLUTION PREVENTION
A. Administrative Controls
The Contractor will designate key personnel for the responsibility of
implementation and conformance of the SWMP for this construction Site.
Including activities such as conducting training to personnel and subcontractors
regarding the SWMP, administering the SWMP, conducting inspections of BMPs
and Site conditions, and conducting project meetings coordinating the
construction activities with the SWMP. Revisions to the SWMP and record
keeping should be provided at the location of the SWMP on the Site during
construction activities.
To ensure that erosion control measures are properly installed and maintained,
the following Administrative Controls are required.
• Preparation/ Policy (SWMP)
• Training
• Inspection/ Conformance/ Compliance
B. Erosion and Sediment Controls
i. Administrative Controls
If, at any time, surface springs or perched water is encountered, the
discharges shall be handled in a manner acceptable to the Colorado
Department of Public Health and Environment.
ii. Demolition Activities
Any demolition activities will precede all proposed construction. All
erosion and sediment control BMP’s shall be installed in advance of
demolition, where possible. If existing infrastructure conflicts with
proposed BMP’s, these areas shall be handled in a manner acceptable to
the Colorado Department of Public Health and Environment.
Stormwater Management Plan The Learning Experience at Miramont Office Park
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iii. Structural Practices
a. Silt Fences & Sediment Control Logs
The existing Site generally slopes to the southeast. To prevent
sediment-laden runoff from impacting the areas surrounding the
Site, a silt fence or sediment control logs will be installed. This will
serve as a boundary control around the perimeter of the Site in
areas where runoff may potentially migrate from the Site. Cleaning
and maintenance will be provided as needed and other BMP’s
may be selected that may function more properly due to Site
conditions.
b. Vehicle Tracking
A vehicle tracking control system will be constructed and
maintained at the entrances to the construction Site. This will be
done in order to prevent mud and debris from being carried onto
the surrounding roadways by construction vehicles.
c. Soil Stockpiles
It is that will be stockpiled for more then 30 days shall be
protected from wind and water erosion within 14 days of stockpile
construction. Stabilization and protection of the stockpile may be
accomplished by any of the following: mulching,
temporary/permanent revegetation operations, or erosion control
matting/geotextiles. If stockpiles are located within 100 feet of a
drainage-way, additional sediment controls such as temporary
dikes or silt fence shall be required. Maximum stockpile height
shall not exceed 15’ at any location.
d. Concrete Washouts
Designated areas with proper signage will be provided on the Site
to allow for concrete trucks or concrete coated equipment to be
washed. Three basic approaches available to the contractor are
an above grade storage area, excavation of a pit in the ground
and a prefabricated haul-away concrete washout container.
Adequate and proper disposal of the wash-out pit contents will be
required once the washout area has reached 2/3 capacity, 2 feet
of build-up and at the completion of construction activities. The
concrete wash-out location is designated on the SWMP site map.
If a pit is to be excavated, the wash-out area shall have adequate
soil buffering capacity and be in an area where shallow
groundwater is not present if dewatered by percolation, otherwise
a liner must be used.
Stormwater Management Plan The Learning Experience at Miramont Office Park
9
e. Inlet Protection
Protective measures will be placed at all existing inlets that could
potentially be impacted by Site runoff prior to grading activities to
prevent sediment from entering the existing off-site storm sewer
system. Once the on-site storm sewer components and systems
are constructed, these same measures will be incorporated
immediately upon completion.
f. Curb Rock Socks
Protective measures will be placed in the curb at regular intervals
to prevent sediment from entering the storm sewer system.
g. Construction Fence
Protective measures will be placed around the perimeter of the
Site that is open to public access to ensure public safety by
limiting access to the Site.
h. Staging Area
Protective measures will be placed on-site for material handling
and storage and construction traffic parking. The staging area will
be located on the existing parking lot.
iv. Non-Structural Practices
Maintenance of the SWMP shall include a weekly inspection of the
facilities. A build-up of excessive sediment occurring in flat areas and
behind erosion control facilities will be removed. Damaged facilities will
be repaired.
C. Materials Handling and Spill Prevention
Construction and building materials will be stored for short periods of time in
relatively flat areas and covered when appropriate. Paints, fertilizers, and any
other liquids or fine grained soluble substances capable of polluting stormwater
discharge will be stored in the original containers in sheltered and secure
locations until time of use. Building material wastes will be properly disposed of
at off-site approved landfills. No fuel is anticipated to be stored on-site and care
will be taken during the fueling of all equipment to ensure no spills occur and if
they do, they are contained and cleaned up immediately. A concrete wash out
area will be provided on-site for concrete truck wash-out waters. Excess
concrete must be removed and disposed as solid waste.
Stormwater Management Plan The Learning Experience at Miramont Office Park
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In case of emergency spills that could reach the storm sewer system or
hazardous waste spills report/call one or more of the following:
- 911;
- Larimer County Sheriff’s Office – (970) 498-5100;
- General State chemical spill reporting – (877) 518-5608;
- For non-hazardous spills contact the Larimer County Sheriff’s Office –
(970) 498-5100
5. FINAL STABILIZATION AND LONG-TERM STORMWATER MANAGEMENT
When construction is completed, all areas of the Site outside of the building and
pavement will be stabilized with slope stabilization and vegetation. Final stabilization is
reached when all soil disturbing activities at the Site have been complete and uniform
vegetative cover has been established with density of at least 70 percent of pre-
disturbance levels, or equivalent permanent, physical erosion reduction methods have
been employed.
Long-term Stormwater Management includes the water quality control volume (WQCV)
provided in the detention pond and a water quality plate on the outlet structure to control
the release rate to provide a 40-hour drain time of the WQCV. Long-term responsibility
for Stormwater Management inspection and maintenance will be the owner.
6. INSPECTION AND MAINTENANCE
Maintenance of erosion control measures shall comply with the criteria set forth in the
Colorado Department of Public Health and Environmental Guidelines, or the following,
whichever is the more stringent. If any part of the erosion control system is found to be
deteriorating, it will be repaired immediately so as not to delay upcoming schedules.
The monitoring of erosion control measures will expand as the project expands.
During active construction, all structural practices will be inspected once every two
weeks and within 24 hours of a storm event that causes surface erosion. Once
construction is complete, but stabilization has not been fully established, all structural
practices will be inspected once every month. A copy of this SWMP shall be maintained
at the Site at all times. Any degradation of structures described in the plan or excessive
accumulation of sediments will be remedied immediately upon discovery.
Records of inspections shall be maintained for review at all times. These records shall
include a record of any spills along with a record of remedial action taken to prevent
further spills. Should changes in the SWMP become necessary, this SWMP shall be
amended as necessary to control pollutants from entering the stormwater discharge.
Stormwater Management Plan The Learning Experience at Miramont Office Park
11
7. CDPS GENERAL PERMIT
The Contractor shall thoroughly read and understand the CDPS General Permit,
Construction Activities Stormwater Discharge Permit and any other relative stormwater
permits required for this project. All required permits shall remain open for the duration
of both phases of the project and it is the contractor’s responsibility to ensure that all
required inspection and maintenance requirements are met both during and between the
phased work.
8. SECURITY FOR EROSION CONTROL
Estimated cost to revegetate the disturbed land to dry grass land for 0.84 acres is
estimated to be $6,345. A financial security for this amount will be provided by the
Owner. See Appendix 3 for the Erosion Control Cost Estimate.
Stormwater Management Plan The Learning Experience at Miramont Office Park
12
9. REFERENCES
• Colorado Department of Public Health and Environment, Water Quality Control
Division. “Colorado Department of Public Health & Environment Guidelines”.
Denver, Colorado: May 1995.
• Urban Drainage and Flood Control District. “Urban Storm Drainage Criteria
Manual – Volume 3”. Denver, Colorado: Revised December 2010.
• Redland “Final Drainage Report for The Learning Experience at Miramont Office
Park”. Fort Collins, Colorado: July 2013.
• CDOT Erosion Control and Stormwater Quality Guide, 2002.
APPENDIX 1
VICINITY MAP
APPENDIX 2
SOIL REPORT
Boardwalk Dr
Oakridge Dr
73
36
494340
494340
494370
494370
494400
494400
494430
494430
494460
494460
494490
494490
4485510
4485510
4485540
4485540
4485570
4485570
4485600
4485600
4485630
4485630
4485660
4485660
4485690
4485690
4485720
4485720
0 40 80 160 240
Feet
0 10 20 40 60
Meters
40° 31' 20''
105° 3' 53''
40° 31' 12''
105° 3' 52''
40° 31' 12''
40° 31' 20''
105° 4' 0'' 105° 4' 0''
Map Scale: 1:1,160 if printed on A size (8.5" x 11") sheet.
Hydrologic Soil Group—Larimer County Area, Colorado
(TLE Miramont)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
6/20/2013
Page 1 of 4
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Political Features
Cities
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:1,160 if printed on A size (8.5" × 11") sheet.
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 accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 13N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 7, May 1, 2009
Date(s) aerial images were photographed: 8/6/2005
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.
Hydrologic Soil Group–Larimer County Area, Colorado
(TLE Miramont)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
6/20/2013
Page 2 of 4
Hydrologic Soil Group
Hydrologic Soil Group— Summary by Map Unit — Larimer County Area, Colorado (CO644)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
36 Fort Collins loam, 3 to 5
percent slopes
B 0.0 0.2%
73 Nunn clay loam, 0 to 1
percent slope
C 4.3 99.8%
Totals for Area of Interest 4.3 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay layer
at or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Hydrologic Soil Group–Larimer County Area, Colorado TLE Miramont
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
6/20/2013
Page 3 of 4
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group–Larimer County Area, Colorado TLE Miramont
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
6/20/2013
Page 4 of 4
Boardwalk Dr
Oakridge Dr
73
36
494360
494360
494380
494380
494400
494400
494420
494420
494440
494440
494460
494460
494480
494480
494500
494500
4485520
4485520
4485540
4485540
4485560
4485560
4485580
4485580
4485600
4485600
4485620
4485620
4485640
4485640
4485660
4485660
4485680
4485680
4485700
4485700
4485720
4485720
4485740
4485740
0 40 80 160 240
Feet
0 10 20 40 60
Meters
40° 31' 20''
105° 3' 52''
40° 31' 12''
105° 3' 52''
40° 31' 12''
40° 31' 20''
105° 4' 0'' 105° 4' 0''
Map Scale: 1:1,130 if printed on A size (8.5" x 11") sheet.
K Factor, Rock Free—Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
.02
.05
.10
.15
.17
.20
.24
.28
.32
.37
.43
.49
.55
.64
Not rated or not available
Political Features
Cities
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:1,130 if printed on A size (8.5" × 11") sheet.
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 accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 13N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 7, May 1, 2009
Date(s) aerial images were photographed: 8/6/2005
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.
K Factor, Rock Free–Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/11/2013
Page 2 of 3
K Factor, Rock Free
K Factor, Rock Free— Summary by Map Unit — Larimer County Area, Colorado (CO644)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
36 Fort Collins loam, 3 to 5
percent slopes
.28 0.0 0.1%
73 Nunn clay loam, 0 to 1
percent slope
.20 4.4 99.9%
Totals for Area of Interest 4.4 100.0%
Description
Erosion factor K indicates the susceptibility of a soil to sheet and rill erosion by
water. Factor K is one of six factors used in the Universal Soil Loss Equation (USLE)
and the Revised Universal Soil Loss Equation (RUSLE) to predict the average
annual rate of soil loss by sheet and rill erosion in tons per acre per year. The
estimates are based primarily on percentage of silt, sand, and organic matter and
on soil structure and saturated hydraulic conductivity (Ksat). Values of K range from
0.02 to 0.69. Other factors being equal, the higher the value, the more susceptible
the soil is to sheet and rill erosion by water.
"Erosion factor Kf (rock free)" indicates the erodibility of the fine-earth fraction, or
the material less than 2 millimeters in size.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Layer Options: Surface Layer
K Factor, Rock Free–Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/11/2013
Page 3 of 3
APPENDIX 3
EROSION CONTROL COST ESTIMATE
Page 1 of 1
The Learning Experience at Miramont
Erosion Control Estimate
Date: 10/04/2013
JN: 12026
UNIT TOTAL
Erosion Control QUANTITY UNIT PRICE COST
Silt Fence 350 LF $1.00 $350
Vehicle Tracking Control Pad 1 EA $1,200.00 $1,200
Inlet Protection 6 EA $125.00 $750
Sediment Control Log 115 LF $2.00 $230
Curb Socks 11 EA $25.00 $275
Erosion Control Blanket 145 SY $5.00 $725
Concrete Washout Area 1 EA $700.00 $700
Erosion Control Subtotal $4,230
Security for Erosion Control
BMPs Cost x 1.5 $6,345
Minimum Security $3,000
Security for Erosion Control $6,345
APPENDIX 4
BMP SEQUENCING CHART
Best Management Practices (BMPs) Mobilization Demolition Grading
Utilities
Installation
Flat Work
Installation
Vertical
Installation Landscape Demobilization
Silt Fence
Vehicle Tracking Control Pad
Inlet Protection
Sediment Control Log
Curb Socks
Stabilized Staging Area
Concrete Washout Area
Vegetative
Temporary Seeding/Mulching
Perminant Seeding/Mulching
Other:
Any existing inlets needing protection
Any time the site will sit dormant longer than 30 days
The Learning Experience at Miramont Office Park
BMP SEQUENCE CHART
APPENDIX 5
UDFCD-BMP FACT SHEETS
Street Sweeping and Vacuuming (SS) SM-7
November 2010 Urban Drainage and Flood Control District SS-1
Urban Storm Drainage Criteria Manual Volume 3
Photograph SS-1. A street sweeper removes sediment and potential
pollutants along the curb line at a construction site. Photo courtesy of
Tom Gore.
Description
Street sweeping and vacuuming remove
sediment that has been tracked onto
roadways to reduce sediment transport
into storm drain systems or a surface
waterway.
Appropriate Uses
Use this practice at construction sites
where vehicles may track sediment
offsite onto paved roadways.
Design and Installation
Street sweeping or vacuuming should be
conducted when there is noticeable
sediment accumulation on roadways adjacent to the construction site. Typically, this will be concentrated
at the entrance/exit to the construction site. Well-maintained stabilized construction entrances, vehicle
tracking controls and tire wash facilities can help reduce the necessary frequency of street sweeping and
vacuuming.
On smaller construction sites, street sweeping can be conducted manually using a shovel and broom.
Never wash accumulated sediment on roadways into storm drains.
Maintenance and Removal
Inspect paved roads around the perimeter of the construction site on a daily basis and more
frequently, as needed. Remove accumulated sediment, as needed.
Following street sweeping, check inlet protection that may have been displaced during street
sweeping.
Inspect area to be swept for materials that may be hazardous prior to beginning sweeping operations.
Street Sweeping/ Vacuuming
Functions
Erosion Control No
Sediment Control Yes
Site/Material Management Yes
Stabilized Staging Area (SSA) SM-6
November 2010 Urban Drainage and Flood Control District SSA-1
Urban Storm Drainage Criteria Manual Volume 3
Photograph SSA-1. Example of a staging area with a gravel surface to
prevent mud tracking and reduce runoff. Photo courtesy of Douglas
County.
Description
A stabilized staging area is a clearly
designated area where construction
equipment and vehicles, stockpiles, waste
bins, and other construction-related
materials are stored. The contractor
office trailer may also be located in this
area. Depending on the size of the
construction site, more than one staging
area may be necessary.
Appropriate Uses
Most construction sites will require a
staging area, which should be clearly
designated in SWMP drawings. The layout
of the staging area may vary depending on
the type of construction activity. Staging areas located in roadways due to space constraints require
special measures to avoid materials being washed into storm inlets.
Design and Installation
Stabilized staging areas should be completed prior to other construction activities beginning on the site.
Major components of a stabilized staging area include:
Appropriate space to contain storage and provide for loading/unloading operations, as well as parking
if necessary.
A stabilized surface, either paved or covered, with 3-inch diameter aggregate or larger.
Perimeter controls such as silt fence, sediment control logs, or other measures.
Construction fencing to prevent unauthorized access to construction materials.
Provisions for Good Housekeeping practices related to materials storage and disposal, as described in
the Good Housekeeping BMP Fact Sheet.
A stabilized construction entrance/exit, as described in the Vehicle Tracking Control BMP Fact Sheet,
to accommodate traffic associated with material delivery and waste disposal vehicles.
Over-sizing the stabilized staging area may result in disturbance of existing vegetation in excess of that
required for the project. This increases costs, as well as
requirements for long-term stabilization following the
construction period. When designing the stabilized staging area,
minimize the area of disturbance to the extent practical.
Stabilized Staging Area
Functions
Erosion Control Yes
Sediment Control Moderate
Site/Material
Yes
SM-6 Stabilized Staging Area (SSA)
SSA-2 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
See Detail SSA-1 for a typical stabilized staging area and SSA-2 for a stabilized staging area when
materials staging in roadways is required.
Maintenance and Removal
Maintenance of stabilized staging areas includes maintaining a stable surface cover of gravel, repairing
perimeter controls, and following good housekeeping practices.
When construction is complete, debris, unused stockpiles and materials should be recycled or properly
disposed. In some cases, this will require disposal of contaminated soil from equipment leaks in an
appropriate landfill. Staging areas should then be permanently stabilized with vegetation or other surface
cover planned for the development.
Minimizing Long-Term Stabilization Requirements
Utilize off-site parking and restrict vehicle access to the site.
Use construction mats in lieu of rock when staging is provided in an area that will not be disturbed
otherwise.
Consider use of a bermed contained area for materials and equipment that do not require a
stabilized surface.
Consider phasing of staging areas to avoid disturbance in an area that will not be otherwise
disturbed.
Stabilized Staging Area (SSA) SM-6
November 2010 Urban Drainage and Flood Control District SSA-3
Urban Storm Drainage Criteria Manual Volume 3
SM-6 Stabilized Staging Area (SSA)
SSA-4 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
Vehicle Tracking Control (VTC) SM-4
November 2010 Urban Drainage and Flood Control District VTC-1
Urban Storm Drainage Criteria Manual Volume 3
Photograph VTC-1. A vehicle tracking control pad constructed with
properly sized rock reduces off-site sediment tracking.
Description
Vehicle tracking controls provide
stabilized construction site access where
vehicles exit the site onto paved public
roads. An effective vehicle tracking
control helps remove sediment (mud or
dirt) from vehicles, reducing tracking onto
the paved surface.
Appropriate Uses
Implement a stabilized construction
entrance or vehicle tracking control where
frequent heavy vehicle traffic exits the
construction site onto a paved roadway. An
effective vehicle tracking control is
particularly important during the following conditions:
Wet weather periods when mud is easily tracked off site.
During dry weather periods where dust is a concern.
When poorly drained, clayey soils are present on site.
Although wheel washes are not required in designs of vehicle tracking controls, they may be needed at
particularly muddy sites.
Design and Installation
Construct the vehicle tracking control on a level surface. Where feasible, grade the tracking control
towards the construction site to reduce off-site runoff. Place signage, as needed, to direct construction
vehicles to the designated exit through the vehicle tracking control. There are several different types of
stabilized construction entrances including:
VTC-1. Aggregate Vehicle Tracking Control. This is a coarse-aggregate surfaced pad underlain by a
geotextile. This is the most common vehicle tracking control, and when properly maintained can be
effective at removing sediment from vehicle tires.
VTC-2. Vehicle Tracking Control with Construction Mat or Turf Reinforcement Mat. This type of
control may be appropriate for site access at very small construction sites with low traffic volume over
vegetated areas. Although this application does not typically remove sediment from vehicles, it helps
protect existing vegetation and provides a stabilized entrance.
Vehicle Tracking Control
Functions
Erosion Control Moderate
Sediment Control Yes
Site/Material Management Yes
SM-4 Vehicle Tracking Control (VTC)
VTC-2 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
Photograph VTC-2. A vehicle tracking control pad with wheel wash
facility. Photo courtesy of Tom Gore.
VTC-3. Stabilized Construction Entrance/Exit with Wheel Wash. This is an aggregate pad, similar
to VTC-1, but includes equipment for tire washing. The wheel wash equipment may be as simple as
hand-held power washing equipment to more advance proprietary systems. When a wheel wash is
provided, it is important to direct wash water to a sediment trap prior to discharge from the site.
Vehicle tracking controls are sometimes installed in combination with a sediment trap to treat runoff.
Maintenance and Removal
Inspect the area for degradation and
replace aggregate or material used for a
stabilized entrance/exit as needed. If the
area becomes clogged and ponds water,
remove and dispose of excess sediment
or replace material with a fresh layer of
aggregate as necessary.
With aggregate vehicle tracking controls,
ensure rock and debris from this area do
not enter the public right-of-way.
Remove sediment that is tracked onto the
public right of way daily or more
frequently as needed. Excess sediment
in the roadway indicates that the
stabilized construction entrance needs
maintenance.
Ensure that drainage ditches at the
entrance/exit area remain clear.
A stabilized entrance should be removed only when there is no longer the potential for vehicle tracking to
occur. This is typically after the site has been stabilized.
When wheel wash equipment is used, be sure that the wash water is discharged to a sediment trap prior to
discharge. Also inspect channels conveying the water from the wash area to the sediment trap and
stabilize areas that may be eroding.
When a construction entrance/exit is removed, excess sediment from the aggregate should be removed
and disposed of appropriately. The entrance should be promptly stabilized with a permanent surface
following removal, typically by paving.
Vehicle Tracking Control (VTC) SM-4
November 2010 Urban Drainage and Flood Control District VTC-3
Urban Storm Drainage Criteria Manual Volume 3
SM-4 Vehicle Tracking Control (VTC)
VTC-4 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
Vehicle Tracking Control (VTC) SM-4
November 2010 Urban Drainage and Flood Control District VTC-5
Urban Storm Drainage Criteria Manual Volume 3
SM-4 Vehicle Tracking Control (VTC)
VTC-6 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
Inlet Protection (IP) SC-6
November 2010 Urban Drainage and Flood Control District IP-1
Urban Storm Drainage Criteria Manual Volume 3
Photograph IP-1. Inlet protection for a curb opening inlet.
Description
Inlet protection consists of permeable
barriers installed around an inlet to
filter runoff and remove sediment prior
to entering a storm drain inlet. Inlet
protection can be constructed from rock
socks, sediment control logs, silt fence,
block and rock socks, or other materials
approved by the local jurisdiction.
Area inlets can also be protected by
over-excavating around the inlet to
form a sediment trap.
Appropriate Uses
Install protection at storm sewer inlets
that are operable during construction.
Consider the potential for tracked-out
sediment or temporary stockpile areas to contribute sediment to inlets when determining which inlets
must be protected. This may include inlets in the general proximity of the construction area, not limited
to downgradient inlets. Inlet protection is not
Design and Installation
a stand-alone BMP and should be used in conjunction with
other upgradient BMPs.
To function effectively, inlet protection measures must be installed to ensure that flows do not bypass the
inlet protection and enter the storm drain without treatment. However, designs must also enable the inlet
to function without completely blocking flows into the inlet in a manner that causes localized flooding.
When selecting the type of inlet protection, consider factors such as type of inlet (e.g., curb or area, sump
or on-grade conditions), traffic, anticipated flows, ability to secure the BMP properly, safety and other
site-specific conditions. For example, block and rock socks will be better suited to a curb and gutter
along a roadway, as opposed to silt fence or sediment control logs, which cannot be properly secured in a
curb and gutter setting, but are effective area inlet protection measures.
Several inlet protection designs are provided in the Design Details. Additionally, a variety of proprietary
products are available for inlet protection that may be approved for use by local governments. If
proprietary products are used, design details and installation procedures from the manufacturer must be
followed. Regardless of the type of inlet protection selected, inlet protection is most effective when
combined with other BMPs such as curb socks and check dams. Inlet protection is often the last barrier
before runoff enters the storm sewer or receiving water.
Design details with notes are provided for these forms of inlet
protection:
IP-1. Block and Rock Sock Inlet Protection for Sump or On-grade
Inlets
IP-2. Curb (Rock) Socks Upstream of Inlet Protection, On-grade
Inlets
Inlet Protection
(various forms)
Functions
Erosion Control No
Sediment Control Yes
Site/Material Management No
SC-6 Inlet Protection (IP)
IP-2 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
IP-3. Rock Sock Inlet Protection for Sump/Area Inlet
IP-4. Silt Fence Inlet Protection for Sump/Area Inlet
IP-5. Over-excavation Inlet Protection
IP-6. Straw Bale Inlet Protection for Sump/Area Inlet
CIP-1. Culvert Inlet Protection
Propriety inlet protection devices should be installed in accordance with manufacturer specifications.
More information is provided below on selecting inlet protection for sump and on-grade locations.
Inlets Located in a Sump
When applying inlet protection in sump conditions, it is important that the inlet continue to function
during larger runoff events. For curb inlets, the maximum height of the protective barrier should be lower
than the top of the curb opening to allow overflow into the inlet during larger storms without excessive
localized flooding. If the inlet protection height is greater than the curb elevation, particularly if the filter
becomes clogged with sediment, runoff will not enter the inlet and may bypass it, possibly causing
localized flooding, public safety issues, and downstream erosion and damage from bypassed flows.
Area inlets located in a sump setting can be protected through the use of silt fence, concrete block and
rock socks (on paved surfaces), sediment control logs/straw wattles embedded in the adjacent soil and
stacked around the area inlet (on pervious surfaces), over-excavation around the inlet, and proprietary
products providing equivalent functions.
Inlets Located on a Slope
For curb and gutter inlets on paved sloping streets, block and rock sock inlet protection is recommended
in conjunction with curb socks in the gutter leading to the inlet. For inlets located along unpaved roads,
also see the Check Dam Fact Sheet.
Maintenance and Removal
Inspect inlet protection frequently. Inspection and maintenance guidance includes:
Inspect for tears that can result in sediment directly entering the inlet, as well as result in the contents
of the BMP (e.g., gravel) washing into the inlet.
Check for improper installation resulting in untreated flows bypassing the BMP and directly entering
the inlet or bypassing to an unprotected downstream inlet. For example, silt fence that has not been
properly trenched around the inlet can result in flows under the silt fence and directly into the inlet.
Look for displaced BMPs that are no longer protecting the inlet. Displacement may occur following
larger storm events that wash away or reposition the inlet protection. Traffic or equipment may also
crush or displace the BMP.
Monitor sediment accumulation upgradient of the inlet protection.
Inlet Protection (IP) SC-6
November 2010 Urban Drainage and Flood Control District IP-3
Urban Storm Drainage Criteria Manual Volume 3
Remove sediment accumulation from the area upstream of the inlet protection, as needed to maintain
BMP effectiveness, typically when it reaches no more than half the storage capacity of the inlet
protection. For silt fence, remove sediment when it accumulates to a depth of no more than 6 inches.
Remove sediment accumulation from the area upstream of the inlet protection as needed to maintain
the functionality of the BMP.
Propriety inlet protection devices should be inspected and maintained in accordance with
manufacturer specifications. If proprietary inlet insert devices are used, sediment should be removed
in a timely manner to prevent devices from breaking and spilling sediment into the storm drain.
Inlet protection must be removed and properly disposed of when the drainage area for the inlet has
reached final stabilization.
SC-6 Inlet Protection (IP)
IP-4 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
Inlet Protection (IP) SC-6
November 2010 Urban Drainage and Flood Control District IP-5
Urban Storm Drainage Criteria Manual Volume 3
SC-6 Inlet Protection (IP)
IP-6 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
Inlet Protection (IP) SC-6
November 2010 Urban Drainage and Flood Control District IP-7
Urban Storm Drainage Criteria Manual Volume 3
Rock Sock (RS) SC-5
November 2010 Urban Drainage and Flood Control District RS-1
Urban Storm Drainage Criteria Manual Volume 3
Photograph RS-1. Rock socks placed at regular intervals in a curb
line can help reduce sediment loading to storm sewer inlets. Rock
socks can also be used as perimeter controls.
Description
A rock sock is constructed of gravel
that has been wrapped by wire mesh or
a geotextile to form an elongated
cylindrical filter. Rock socks are
typically used either as a perimeter
control or as part of inlet protection.
When placed at angles in the curb line,
rock socks are typically referred to as
curb socks. Rock socks are intended to
trap sediment from stormwater runoff
that flows onto roadways as a result of
construction activities.
Appropriate Uses
Rock socks can be used at the perimeter
of a disturbed area to control localized
sediment loading. A benefit of rock
socks as opposed to other perimeter controls is that they do not have to be trenched or staked into the
ground; therefore, they are often used on roadway construction projects where paved surfaces are present.
Use rock socks in inlet protection applications when the construction of a roadway is substantially
complete and the roadway has been directly connected to a receiving storm system.
Design and Installation
When rock socks are used as perimeter controls, the maximum recommended tributary drainage area per
100 lineal feet of rock socks is approximately 0.25 acres with disturbed slope length of up to 150 feet and
a tributary slope gradient no steeper than 3:1. A rock sock design detail and notes are provided in Detail
RS-1. Also see the Inlet Protection Fact Sheet for design and installation guidance when rock socks are
used for inlet protection and in the curb line.
When placed in the gutter adjacent to a curb, rock socks should protrude no more than two feet from the
curb in order for traffic to pass safely. If located in a high traffic area, place construction markers to alert
drivers and street maintenance workers of their presence.
Maintenance and Removal
Rock socks are susceptible to displacement and breaking due to vehicle traffic. Inspect rock socks for
damage and repair or replace as necessary. Remove sediment by sweeping or vacuuming as needed to
maintain the functionality of the BMP, typically when sediment
has accumulated behind the rock sock to one-half of the sock's
height.
Once upstream stabilization is complete, rock socks and
accumulated sediment should be removed and properly disposed.
Rock Sock
Functions
Erosion Control No
Sediment Control Yes
Site/Material Management No
SC-5 Rock Sock (RS)
RS-2 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
Rock Sock (RS) SC-5
November 2010 Urban Drainage and Flood Control District RS-3
Urban Storm Drainage Criteria Manual Volume 3
Sediment Control Log (SCL) SC-2
November 2010 Urban Drainage and Flood Control District SCL-1
Urban Storm Drainage Criteria Manual Volume 3
Photographs SCL-1 and SCL-2. Sediment control logs used as 1) a
perimeter control around a soil stockpile; and, 2) as a "J-hook"
perimeter control at the corner of a construction site.
Description
A sediment control log is a linear roll
made of natural materials such as
straw, coconut fiber, or other fibrous
material trenched into the ground and
held with a wooden stake. Sediment
control logs are also often referred to
as "straw wattles." They are used as a
sediment barrier to intercept sheet flow
runoff from disturbed areas.
Appropriate Uses
Sediment control logs can be used in
the following applications to trap
sediment:
As perimeter control for stockpiles
and the site.
As part of inlet protection designs.
As check dams in small drainage
ditches. (Sediment control logs
are not intended for use in
channels with high flow
velocities.)
On disturbed slopes to shorten flow
lengths (as an erosion control).
As part of multi-layered perimeter control along a receiving water such as a stream, pond or wetland.
Sediment control logs work well in combination with other layers of erosion and sediment controls.
Design and Installation
Sediment control logs should be installed along the contour to avoid concentrating flows. The maximum
allowable tributary drainage area per 100 lineal feet of sediment control log, installed along the contour, is
approximately 0.25 acres with a disturbed slope length of up to 150 feet and a tributary slope gradient no
steeper than 3:1. Longer and steeper slopes require additional measures. This recommendation only
applies to sediment control logs installed along the contour. When installed for other uses, such as
perimeter control, it should be installed in a way that will not
produce concentrated flows. For example, a "J-hook"
installation may be appropriate to force runoff to pond and
evaporate or infiltrate in multiple areas rather than concentrate
and cause erosive conditions parallel to the BMP.
Sediment Control Log
Functions
Erosion Control Moderate
Sediment Control Yes
Site/Material Management No
SC-2 Sediment Control Log (SCL)
SCL-2 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
Although sediment control logs initially allow runoff to flow through the BMP, they can quickly become
a barrier and should be installed is if they are impermeable.
Design details and notes for sediment control logs are provided in Detail SCL-1. Sediment logs must be
properly trenched and staked into the ground to prevent undercutting, bypassing and displacement. When
installed on slopes, sediment control logs should be installed along the contours (i.e., perpendicular to
flow).
Improper installation can lead to poor performance. Be sure that sediment control logs are properly
trenched, anchored and tightly jointed.
Maintenance and Removal
Be aware that sediment control logs will eventually degrade. Remove accumulated sediment before the
depth is one-half the height of the sediment log and repair damage to the sediment log, typically by
replacing the damaged section.
Once the upstream area is stabilized, remove and properly dispose of the logs. Areas disturbed beneath
the logs may need to be seeded and mulched. Sediment control logs that are biodegradable may
occasionally be left in place (e.g., when logs are used in conjunction with erosion control blankets as
permanent slope breaks). However, removal of sediment control logs after final stabilization is typically
recommended when used in perimeter control, inlet protection and check dam applications.
Sediment Control Log (SCL) SC-2
November 2010 Urban Drainage and Flood Control District SCL-3
Urban Storm Drainage Criteria Manual Volume 3
SC-2 Sediment Control Log (SCL)
SCL-4 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
Sediment Control Log (SCL) SC-2
November 2010 Urban Drainage and Flood Control District SCL-5
Urban Storm Drainage Criteria Manual Volume 3
Silt Fence (SF) SC-1
November 2010 Urban Drainage and Flood Control District SF-1
Urban Storm Drainage Criteria Manual Volume 3
Photograph SF-1. Silt fence creates a sediment barrier, forcing
sheet flow runoff to evaporate or infiltrate.
Description
A silt fence is a woven geotextile fabric
attached to wooden posts and trenched
into the ground. It is designed as a
sediment barrier to intercept sheet flow
runoff from disturbed areas.
Appropriate Uses
A silt fence can be used where runoff is
conveyed from a disturbed area as sheet
flow. Silt fence is not designed to
receive concentrated flow or to be used
as a filter fabric. Typical uses include:
Down slope of a disturbed area to
accept sheet flow.
Along the perimeter of a receiving
water such as a stream, pond or
wetland.
At the perimeter of a construction site.
Design and Installation
Silt fence should be installed along the contour of slopes so that it intercepts sheet flow. The maximum
recommended tributary drainage area per 100 lineal feet of silt fence, installed along the contour, is
approximately 0.25 acres with a disturbed slope length of up to 150 feet and a tributary slope gradient no
steeper than 3:1. Longer and steeper slopes require additional measures. This recommendation only
applies to silt fence installed along the contour. Silt fence installed for other uses, such as perimeter
control, should be installed in a way that will not produce concentrated flows. For example, a "J-hook"
installation may be appropriate to force runoff to pond and evaporate or infiltrate in multiple areas rather
than concentrate and cause erosive conditions parallel to the silt fence.
See Detail SF-1 for proper silt fence installation, which involves proper trenching, staking, securing the
fabric to the stakes, and backfilling the silt fence. Properly installed silt fence should not be easily pulled
out by hand and there should be no gaps between the ground and the fabric.
Silt fence must meet the minimum allowable strength requirements, depth of installation requirement, and
other specifications in the design details. Improper installation
of silt fence is a common reason for silt fence failure; however,
when properly installed and used for the appropriate purposes, it
can be highly effective.
Silt Fence
Functions
Erosion Control No
Sediment Control Yes
Site/Material Management No
SC-1 Silt Fence (SF)
SF-2 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
Photograph SF-2. When silt fence is not installed along
the contour, a "J-hook" installation may be appropriate
to ensure that the BMP does not create concentrated
flow parallel to the silt fence. Photo courtesy of Tom
Gore.
Maintenance and Removal
Inspection of silt fence includes observing the
material for tears or holes and checking for slumping
fence and undercut areas bypassing flows. Repair of
silt fence typically involves replacing the damaged
section with a new section. Sediment accumulated
behind silt fence should be removed, as needed to
maintain BMP effectiveness, typically before it
reaches a depth of 6 inches.
Silt fence may be removed when the upstream area
has reached final stabilization.
Silt Fence (SF) SC-1
November 2010 Urban Drainage and Flood Control District SF-3
Urban Storm Drainage Criteria Manual Volume 3
SC-1 Silt Fence (SF)
SF-4 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
Good Housekeeping Practices (GH) MM-3
November 2010 Urban Drainage and Flood Control District GH-1
Urban Storm Drainage Criteria Manual Volume 3
Photographs GH-1 and GH-2. Proper materials
storage and secondary containment for fuel tanks
are important good housekeeping practices. Photos
courtesy of CDOT and City of Aurora.
Description
Implement construction site good housekeeping practices to
prevent pollution associated with solid, liquid and hazardous
construction-related materials and wastes. Stormwater
Management Plans (SWMPs) should clearly specify BMPs
including these good housekeeping practices:
Provide for waste management.
Establish proper building material staging areas.
Designate paint and concrete washout areas.
Establish proper equipment/vehicle fueling and
maintenance practices.
Control equipment/vehicle washing and allowable non-
stormwater discharges.
Develop a spill prevention and response plan.
Acknowledgement: This Fact Sheet is based directly on
EPA guidance provided in Developing Your Stormwater
Pollution Prevent Plan (EPA 2007).
Appropriate Uses
Good housekeeping practices are necessary at all construction sites.
Design and Installation
The following principles and actions should be addressed in SWMPs:
Provide for Waste Management. Implement management procedures and practices to prevent or
reduce the exposure and transport of pollutants in stormwater from solid, liquid and sanitary wastes
that will be generated at the site. Practices such as trash disposal, recycling, proper material handling,
and cleanup measures can reduce the potential for stormwater runoff to pick up construction site
wastes and discharge them to surface waters. Implement a comprehensive set of waste-management
practices for hazardous or toxic materials, such as paints, solvents, petroleum products, pesticides,
wood preservatives, acids, roofing tar, and other materials. Practices should include storage,
handling, inventory, and cleanup procedures, in case of spills. Specific practices that should be
considered include:
Solid or Construction Waste
o Designate trash and bulk waste-collection areas on-
site.
Good Housekeeping
Functions
Erosion Control No
Sediment Control No
Site/Material Management Yes
MM-3 Good Housekeeping Practices (GH)
GH-2 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
Photograph GH-3. Locate portable toilet facilities on level
surfaces away from waterways and storm drains. Photo
courtesy of WWE.
o Recycle materials whenever possible (e.g., paper, wood, concrete, oil).
o Segregate and provide proper disposal options for hazardous material wastes.
o Clean up litter and debris from the construction site daily.
o Locate waste-collection areas away from streets, gutters, watercourses, and storm drains. Waste-
collection areas (dumpsters, and such) are often best located near construction site entrances to
minimize traffic on disturbed soils. Consider secondary containment around waste collection
areas to minimize the likelihood of contaminated discharges.
o Empty waste containers before they are full and overflowing.
Sanitary and Septic Waste
o Provide convenient, well-maintained, and properly located toilet facilities on-site.
o Locate toilet facilities away from storm drain inlets and waterways to prevent accidental spills
and contamination of stormwater.
o Maintain clean restroom facilities and empty portable toilets regularly.
o Where possible, provide secondary containment pans under portable toilets.
o Provide tie-downs or stake-downs for portable toilets.
o Educate employees, subcontractors, and suppliers on locations of facilities.
o Treat or dispose of sanitary and septic waste in accordance with state or local regulations. Do not
discharge or bury wastewater at the construction site.
o Inspect facilities for leaks. If found, repair or replace immediately.
o Special care is necessary during maintenance (pump out) to ensure that waste and/or biocide are
not spilled on the ground.
Hazardous Materials and Wastes
o Develop and implement employee and
subcontractor education, as needed, on
hazardous and toxic waste handling,
storage, disposal, and cleanup.
o Designate hazardous waste-collection
areas on-site.
o Place all hazardous and toxic material
wastes in secondary containment.
Good Housekeeping Practices (GH) MM-3
November 2010 Urban Drainage and Flood Control District GH-3
Urban Storm Drainage Criteria Manual Volume 3
o Hazardous waste containers should be inspected to ensure that all containers are labeled properly
and that no leaks are present.
Establish Proper Building Material Handling and Staging Areas. The SWMP should include
comprehensive handling and management procedures for building materials, especially those that are
hazardous or toxic. Paints, solvents, pesticides, fuels and oils, other hazardous materials or building
materials that have the potential to contaminate stormwater should be stored indoors or under cover
whenever possible or in areas with secondary containment. Secondary containment measures prevent
a spill from spreading across the site and may include dikes, berms, curbing, or other containment
methods. Secondary containment techniques should also ensure the protection of groundwater.
Designate staging areas for activities such as fueling vehicles, mixing paints, plaster, mortar, and
other potential pollutants. Designated staging areas enable easier monitoring of the use of materials
and clean up of spills. Training employees and subcontractors is essential to the success of this
pollution prevention principle. Consider the following specific materials handling and staging
practices:
o Train employees and subcontractors in proper handling and storage practices.
o Clearly designate site areas for staging and storage with signs and on construction drawings.
Staging areas should be located in areas central to the construction site. Segment the staging area
into sub-areas designated for vehicles, equipment, or stockpiles. Construction entrances and exits
should be clearly marked so that delivery vehicles enter/exit through stabilized areas with vehicle
tracking controls (See Vehicle Tracking Control Fact Sheet).
o Provide storage in accordance with Spill Protection, Control and Countermeasures (SPCC)
requirements and plans and provide cover and impermeable perimeter control, as necessary, for
hazardous materials and contaminated soils that must be stored on site.
o Ensure that storage containers are regularly inspected for leaks, corrosion, support or foundation
failure, or other signs of deterioration and tested for soundness.
o Reuse and recycle construction materials when possible.
Designate Concrete Washout Areas. Concrete contractors should be encouraged to use the washout
facilities at their own plants or dispatch facilities when feasible; however, concrete washout
commonly occurs on construction sites. If it is necessary to provide for concrete washout areas on-
site, designate specific washout areas and design facilities to handle anticipated washout water.
Washout areas should also be provided for paint and stucco operations. Because washout areas can
be a source of pollutants from leaks or spills, care must be taken with regard to their placement and
proper use. See the Concrete Washout Area Fact Sheet for detailed guidance.
Both self-constructed and prefabricated washout containers can fill up quickly when concrete, paint,
and stucco work are occurring on large portions of the site. Be sure to check for evidence that
contractors are using the washout areas and not dumping materials onto the ground or into drainage
facilities. If the washout areas are not being used regularly, consider posting additional signage,
relocating the facilities to more convenient locations, or providing training to workers and
contractors.
When concrete, paint, or stucco is part of the construction process, consider these practices which will
help prevent contamination of stormwater. Include the locations of these areas and the maintenance
and inspection procedures in the SWMP.
MM-3 Good Housekeeping Practices (GH)
GH-4 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
o Do not washout concrete trucks or equipment into storm drains, streets, gutters, uncontained
areas, or streams. Only use designated washout areas.
o Establish washout areas and advertise their locations with signs. Ensure that signage remains in
good repair.
o Provide adequate containment for the amount of wash water that will be used.
o Inspect washout structures daily to detect leaks or tears and to identify when materials need to be
removed.
o Dispose of materials properly. The preferred method is to allow the water to evaporate and to
recycle the hardened concrete. Full service companies may provide dewatering services and
should dispose of wastewater properly. Concrete wash water can be highly polluted. It should
not be discharged to any surface water, storm sewer system, or allowed to infiltrate into the
ground in the vicinity of waterbodies. Washwater should not be discharged to a sanitary sewer
system without first receiving written permission from the system operator.
Establish Proper Equipment/Vehicle Fueling and Maintenance Practices. Create a clearly
designated on-site fueling and maintenance area that is clean and dry. The on-site fueling area should
have a spill kit, and staff should know how to use it. If possible, conduct vehicle fueling and
maintenance activities in a covered area. Consider the following practices to help prevent the
discharge of pollutants to stormwater from equipment/vehicle fueling and maintenance. Include the
locations of designated fueling and maintenance areas and inspection and maintenance procedures in
the SWMP.
o Train employees and subcontractors in proper fueling procedures (stay with vehicles during
fueling, proper use of pumps, emergency shutoff valves, etc.).
o Inspect on-site vehicles and equipment regularly for leaks, equipment damage, and other service
problems.
o Clearly designate vehicle/equipment service areas away from drainage facilities and watercourses
to prevent stormwater run-on and runoff.
o Use drip pans, drip cloths, or absorbent pads when replacing spent fluids.
o Collect all spent fluids, store in appropriate labeled containers in the proper storage areas, and
recycle fluids whenever possible.
Control Equipment/Vehicle Washing and Allowable Non-Stormwater Discharges. Implement
practices to prevent contamination of surface and groundwater from equipment and vehicle wash
water. Representative practices include:
o Educate employees and subcontractors on proper washing procedures.
o Use off-site washing facilities, when available.
o Clearly mark the washing areas and inform workers that all washing must occur in this area.
o Contain wash water and treat it using BMPs. Infiltrate washwater when possible, but maintain
separation from drainage paths and waterbodies.
Good Housekeeping Practices (GH) MM-3
November 2010 Urban Drainage and Flood Control District GH-5
Urban Storm Drainage Criteria Manual Volume 3
o Use high-pressure water spray at vehicle washing facilities without detergents. Water alone can
remove most dirt adequately.
o Do not conduct other activities, such as vehicle repairs, in the wash area.
o Include the location of the washing facilities and the inspection and maintenance procedures in
the SWMP.
Develop a Spill Prevention and Response Plan. Spill prevention and response procedures must be
identified in the SWMP. Representative procedures include identifying ways to reduce the chance of
spills, stop the source of spills, contain and clean up spills, dispose of materials contaminated by
spills, and train personnel responsible for spill prevention and response. The plan should also specify
material handling procedures and storage requirements and ensure that clear and concise spill cleanup
procedures are provided and posted for areas in which spills may potentially occur. When developing
a spill prevention plan, include the following:
o Note the locations of chemical storage areas, storm drains, tributary drainage areas, surface
waterbodies on or near the site, and measures to stop spills from leaving the site.
o Provide proper handling and safety procedures for each type of waste. Keep Material Safety Data
Sheets (MSDSs) for chemical used on site with the SWMP.
o Establish an education program for employees and subcontractors on the potential hazards to
humans and the environment from spills and leaks.
o Specify how to notify appropriate authorities, such as police and fire departments, hospitals, or
municipal sewage treatment facilities to request assistance. Emergency procedures and contact
numbers should be provided in the SWMP and posted at storage locations.
o Describe the procedures, equipment and materials for immediate cleanup of spills and proper
disposal.
o Identify personnel responsible for implementing the plan in the event of a spill. Update the spill
prevention plan and clean up materials as changes occur to the types of chemicals stored and used
at the facility.
MM-3 Good Housekeeping Practices (GH)
GH-6 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
Spill Prevention, Control, and Countermeasure (SPCC) Plan
Construction sites may be subject to 40 CFR Part 112 regulations that require the preparation and
implementation of a SPCC Plan to prevent oil spills from aboveground and underground storage tanks.
The facility is subject to this rule if it is a non-transportation-related facility that:
Has a total storage capacity greater than 1,320 gallons or a completely buried storage capacity
greater than 42,000 gallons.
Could reasonably be expected to discharge oil in quantities that may be harmful to navigable waters
of the United States and adjoining shorelines.
Furthermore, if the facility is subject to 40 CFR Part 112, the SWMP should reference the SPCC Plan.
To find out more about SPCC Plans, see EPA's website on SPPC at www.epa.gov/oilspill/spcc.htm.
Reporting Oil Spills
In the event of an oil spill, contact the National Response Center toll free at 1-800-424- 8802 for
assistance, or for more details, visit their website: www.nrc.uscg.mil.
Maintenance and Removal
Effective implementation of good housekeeping practices is dependent on clear designation of personnel
responsible for supervising and implementing good housekeeping programs, such as site cleanup and
disposal of trash and debris, hazardous material management and disposal, vehicle and equipment
maintenance, and other practices. Emergency response "drills" may aid in emergency preparedness.
Checklists may be helpful in good housekeeping efforts.
Staging and storage areas require permanent stabilization when the areas are no longer being used for
construction-related activities.
Construction-related materials, debris and waste must be removed from the construction site once
construction is complete.
Design Details
See the following Fact Sheets for related Design Details:
MM-1 Concrete Washout Area
MM-2 Stockpile Management
SM-4 Vehicle Tracking Control
Design details are not necessary for other good housekeeping practices; however, be sure to designate
where specific practices will occur on the appropriate construction drawings.
Concrete Washout Area (CWA) MM-1
November 2010 Urban Drainage and Flood Control District CWA-1
Urban Storm Drainage Criteria Manual Volume 3
Photograph CWA-1. Example of concrete washout area. Note gravel
tracking pad for access and sign.
Description
Concrete waste management involves
designating and properly managing a
specific area of the construction site as a
concrete washout area. A concrete
washout area can be created using one of
several approaches designed to receive
wash water from washing of tools and
concrete mixer chutes, liquid concrete
waste from dump trucks, mobile batch
mixers, or pump trucks. Three basic
approaches are available: excavation of a
pit in the ground, use of an above ground
storage area, or use of prefabricated haul-
away concrete washout containers.
Surface discharges of concrete washout
water from construction sites are prohibited.
Appropriate Uses
Concrete washout areas must be designated on all sites that will generate concrete wash water or liquid
concrete waste from onsite concrete mixing or concrete delivery.
Because pH is a pollutant of concern for washout activities, when unlined pits are used for concrete
washout, the soil must have adequate buffering capacity to result in protection of state groundwater
standards; otherwise, a liner/containment must be used. The following management practices are
recommended to prevent an impact from unlined pits to groundwater:
The use of the washout site should be temporary (less than 1 year), and
The washout site should be not be located in an area where shallow groundwater may be present, such
as near natural drainages, springs, or wetlands.
Design and Installation
Concrete washout activities must be conducted in a manner that does not contribute pollutants to surface
waters or stormwater runoff. Concrete washout areas may be lined or unlined excavated pits in the
ground, commercially manufactured prefabricated washout containers, or aboveground holding areas
constructed of berms, sandbags or straw bales with a plastic liner.
Although unlined washout areas may be used, lined pits may be required to protect groundwater under
certain conditions.
Do not locate an unlined washout area within 400 feet
of any natural drainage pathway or waterbody or
within 1,000 feet of any wells or drinking water
sources. Even for lined concrete washouts, it is
advisable to locate the facility away from waterbodies
and drainage paths. If site constraints make these
Concrete Washout Area
Functions
Erosion Control No
Sediment Control No
Site/Material Management Yes
MM-1 Concrete Washout Area (CWA)
CWA-2 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
setbacks infeasible or if highly permeable soils exist in the area, then the pit must be installed with an
impermeable liner (16 mil minimum thickness) or surface storage alternatives using prefabricated
concrete washout devices or a lined aboveground storage area should be used.
Design details with notes are provided in Detail CWA-1 for pits and CWA-2 for aboveground storage
areas. Pre-fabricated concrete washout container information can be obtained from vendors.
Maintenance and Removal
A key consideration for concrete washout areas is to ensure that adequate signage is in place identifying
the location of the washout area. Part of inspecting and maintaining washout areas is ensuring that
adequate signage is provided and in good repair and that the washout area is being used, as opposed to
washout in non-designated areas of the site.
Remove concrete waste in the washout area, as needed to maintain BMP function (typically when filled to
about two-thirds of its capacity). Collect concrete waste and deliver offsite to a designated disposal
location.
Upon termination of use of the washout site, accumulated solid waste, including concrete waste and any
contaminated soils, must be removed from the site to prevent on-site disposal of solid waste. If the wash
water is allowed to evaporate and the concrete hardens, it may be recycled.
Photograph CWA-3. Earthen concrete washout. Photo
courtesy of CDOT.
Photograph CWA-2. Prefabricated concrete washout. Photo
courtesy of CDOT.
Concrete Washout Area (CWA) MM-1
November 2010 Urban Drainage and Flood Control District CWA-3
Urban Storm Drainage Criteria Manual Volume 3
MM-1 Concrete Washout Area (CWA)
CWA-4 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
Temporary Outlet Protection (TOP) EC-8
November 2010 Urban Drainage and Flood Control District TOP-1
Urban Storm Drainage Criteria Manual Volume 3
Photograph TOP-1. Riprap outlet protection.
Description
Outlet protection helps to reduce erosion
immediately downstream of a pipe,
culvert, slope drain, rundown or other
conveyance with concentrated, high-
velocity flows. Typical outlet protection
consists of riprap or rock aprons at the
conveyance outlet.
Appropriate Uses
Outlet protection should be used when a
conveyance discharges onto a disturbed
area where there is potential for accelerated
erosion due to concentrated flow. Outlet
protection should be provided where the velocity at the culvert outlet exceeds the maximum permissible
velocity of the material in the receiving channel.
Note: This Fact Sheet and detail are for temporary outlet protection, outlets that are intended to be used
for less than 2 years. For permanent, long-term outlet protection, see the Major Drainage chapter of
Volume 1.
Design and Installation
Design outlet protection to handle runoff from the largest drainage area that may be contributing runoff
during construction (the drainage area may change as a result of grading). Key in rock, around the entire
perimeter of the apron, to a minimum depth of 6 inches for stability. Extend riprap to the height of the
culvert or the normal flow depth of the downstream channel, whichever is less. Additional erosion
control measures such as vegetative lining, turf reinforcement mat and/or other channel lining methods
may be required downstream of the outlet protection if the channel is susceptible to erosion. See Design
Detail OP-1 for additional information.
Maintenance and Removal
Inspect apron for damage and displaced rocks. If rocks are missing or significantly displaced, repair or
replace as necessary. If rocks are continuously missing or displaced, consider increasing the size of the
riprap or deeper keying of the perimeter.
Remove sediment accumulated at the outlet before the outlet protection becomes buried and ineffective.
When sediment accumulation is noted, check that upgradient BMPs, including inlet protection, are in
effective operating condition.
Outlet protection may be removed once the pipe is no longer
draining an upstream area, or once the downstream area has
been sufficiently stabilized. If the drainage pipe is
permanent, outlet protection can be left in place; however,
permanent outlet protection should be designed and
constructed in accordance with the requirements of the
Major Drainage chapter of Volume 2.
Outlet Protection
Functions
Erosion Control Yes
Sediment Control Moderate
Site/Material Management No
EC-8 Temporary Outlet Protection (TOP)
TOP-2 Urban Drainage and Flood Control District November 2010
Urban Storm Drainage Criteria Manual Volume 3
Temporary Outlet Protection (TOP) EC-8
November 2010 Urban Drainage and Flood Control District TOP-3
Urban Storm Drainage Criteria Manual Volume 3
Mulching (MU) EC-4
June 2012 Urban Drainage and Flood Control District MU-1
Urban Storm Drainage Criteria Manual Volume 3
Photograph MU-1. An area that was recently seeded, mulched,
and crimped.
Description
Mulching consists of evenly applying
straw, hay, shredded wood mulch, rock,
bark or compost to disturbed soils and
securing the mulch by crimping, tackifiers,
netting or other measures. Mulching helps
reduce erosion by protecting bare soil
from rainfall impact, increasing
infiltration, and reducing runoff.
Although often applied in conjunction
with temporary or permanent seeding, it
can also be used for temporary
stabilization of areas that cannot be
reseeded due to seasonal constraints.
Mulch can be applied either using
standard mechanical dry application
methods or using hydromulching equipment
that hydraulically applies a slurry of water,
wood fiber mulch, and often a tackifier.
Appropriate Uses
Use mulch in conjunction with seeding to help protect the seedbed and stabilize the soil. Mulch can also
be used as a temporary cover on low to mild slopes to help temporarily stabilize disturbed areas where
growing season constraints prevent effective reseeding. Disturbed areas should be properly mulched and
tacked, or seeded, mulched and tacked promptly after final grade is reached (typically within no longer
than 14 days) on portions of the site not otherwise permanently stabilized.
Standard dry mulching is encouraged in most jurisdictions; however, hydromulching may not be allowed
in certain jurisdictions or may not be allowed near waterways.
Do not apply mulch during windy conditions.
Design and Installation
Prior to mulching, surface-roughen areas by rolling with a crimping or punching type roller or by track
walking. Track walking should only be used where other methods are impractical because track walking
with heavy equipment typically compacts the soil.
A variety of mulches can be used effectively at construction
sites. Consider the following:
Mulch
Functions
Erosion Control Yes
Sediment Control Moderate
Site/Material Management No
EC-4 Mulching (MU)
MU-2 Urban Drainage and Flood Control District June 2012
Urban Storm Drainage Criteria Manual Volume 3
Clean, weed-free and seed-free cereal grain straw should be applied evenly at a rate of 2 tons per acre and
must be tacked or fastened by a method suitable for the condition of the site. Straw mulch must be
anchored (and not merely placed) on the surface. This can be accomplished mechanically by crimping or
with the aid of tackifiers or nets. Anchoring with a crimping implement is preferred, and is the
recommended method for areas flatter than 3:1. Mechanical crimpers must be capable of tucking the long
mulch fibers into the soil to a depth of 3 inches without cutting them. An agricultural disk, while not an
ideal substitute, may work if the disk blades are dull or blunted and set vertically; however, the frame may
have to be weighted to afford proper soil penetration.
Grass hay may be used in place of straw; however, because hay is comprised of the entire plant including
seed, mulching with hay may seed the site with non-native grass species which might in turn out-compete
the native seed. Alternatively, native species of grass hay may be purchased, but can be difficult to find
and are more expensive than straw. Purchasing and utilizing a certified weed-free straw is an easier and
less costly mulching method. When using grass hay, follow the same guidelines as for straw (provided
above).
On small areas sheltered from the wind and heavy runoff, spraying a tackifier on the mulch is satisfactory
for holding it in place. For steep slopes and special situations where greater control is needed, erosion
control blankets anchored with stakes should be used instead of mulch.
Hydraulic mulching consists of wood cellulose fibers mixed with water and a tackifying agent and should
be applied at a rate of no less than 1,500 pounds per acre (1,425 lbs of fibers mixed with at least 75 lbs of
tackifier) with a hydraulic mulcher. For steeper slopes, up to 2000 pounds per acre may be required for
effective hydroseeding. Hydromulch typically requires up to 24 hours to dry; therefore, it should not be
applied immediately prior to inclement weather. Application to roads, waterways and existing vegetation
should be avoided.
Erosion control mats, blankets, or nets are recommended to help stabilize steep slopes (generally 3:1 and
steeper) and waterways. Depending on the product, these may be used alone or in conjunction with grass
or straw mulch. Normally, use of these products will be restricted to relatively small areas.
Biodegradable mats made of straw and jute, straw-coconut, coconut fiber, or excelsior can be used instead
of mulch. (See the ECM/TRM BMP for more information.)
Some tackifiers or binders may be used to anchor mulch. Check with the local jurisdiction for allowed
tackifiers. Manufacturer's recommendations should be followed at all times. (See the Soil Binder BMP
for more information on general types of tackifiers.)
Rock can also be used as mulch. It provides protection of exposed soils to wind and water erosion and
allows infiltration of precipitation. An aggregate base course can be spread on disturbed areas for
temporary or permanent stabilization. The rock mulch layer should be thick enough to provide full
coverage of exposed soil on the area it is applied.
Maintenance and Removal
After mulching, the bare ground surface should not be more than 10 percent exposed. Reapply mulch, as
needed, to cover bare areas.
Temporary and Permanent Seeding (TS/PS) EC-2
June 2012 Urban Drainage and Flood Control District TS/PS-1
Urban Storm Drainage Criteria Manual Volume 3
Photograph TS/PS -1. Equipment used to drill seed. Photo courtesy of
Douglas County.
Description
Temporary seeding can be used to
stabilize disturbed areas that will be
inactive for an extended period.
Permanent seeding should be used to
stabilize areas at final grade that will not
be otherwise stabilized. Effective seeding
includes preparation of a seedbed,
selection of an appropriate seed mixture,
proper planting techniques, and protection
of the seeded area with mulch, geotextiles,
or other appropriate measures.
Appropriate Uses
When the soil surface is disturbed and
will remain inactive for an extended
period (typically 30 days or longer),
proactive stabilization measures should be implemented. If the inactive period is short-lived (on the order
of two weeks), techniques such as surface roughening may be appropriate. For longer periods of
inactivity, temporary seeding and mulching can provide effective erosion control. Permanent seeding
should be used on finished areas that have not been otherwise stabilized.
Typically, local governments have their own seed mixes and timelines for seeding. Check jurisdictional
requirements for seeding and temporary stabilization.
Design and Installation
Effective seeding requires proper seedbed preparation, selection of an appropriate seed mixture, use of
appropriate seeding equipment to ensure proper coverage and density, and protection with mulch or fabric
until plants are established.
The USDCM Volume 2 Revegetation Chapter contains detailed seed mix, soil preparations, and seeding
and mulching recommendations that may be referenced to supplement this Fact Sheet.
Drill seeding is the preferred seeding method. Hydroseeding is not recommended except in areas where
steep slopes prevent use of drill seeding equipment, and even in these instances it is preferable to hand
seed and mulch. Some jurisdictions do not allow hydroseeding or hydromulching.
Seedbed Preparation
Prior to seeding, ensure that areas to be revegetated have
soil conditions capable of supporting vegetation. Overlot
grading can result in loss of topsoil, resulting in poor quality
subsoils at the ground surface that have low nutrient value,
little organic matter content, few soil microorganisms,
rooting restrictions, and conditions less conducive to
infiltration of precipitation. As a result, it is typically
necessary to provide stockpiled topsoil, compost, or other
Temporary and Permanent Seeding
Functions
Erosion Control Yes
Sediment Control No
Site/Material Management No
EC-2 Temporary and Permanent Seeding (TS/PS)
TS/PS-2 Urban Drainage and Flood Control District June 2012
Urban Storm Drainage Criteria Manual Volume 3
soil amendments and rototill them into the soil to a depth of 6 inches or more.
Topsoil should be salvaged during grading operations for use and spread on areas to be revegetated later.
Topsoil should be viewed as an important resource to be utilized for vegetation establishment, due to its
water-holding capacity, structure, texture, organic matter content, biological activity, and nutrient content.
The rooting depth of most native grasses in the semi-arid Denver metropolitan area is 6 to 18 inches. At a
minimum, the upper 6 inches of topsoil should be stripped, stockpiled, and ultimately respread across
areas that will be revegetated.
Where topsoil is not available, subsoils should be amended to provide an appropriate plant-growth
medium. Organic matter, such as well digested compost, can be added to improve soil characteristics
conducive to plant growth. Other treatments can be used to adjust soil pH conditions when needed. Soil
testing, which is typically inexpensive, should be completed to determine and optimize the types and
amounts of amendments that are required.
If the disturbed ground surface is compacted, rip or rototill the surface prior to placing topsoil. If adding
compost to the existing soil surface, rototilling is necessary. Surface roughening will assist in placement
of a stable topsoil layer on steeper slopes, and allow infiltration and root penetration to greater depth.
Prior to seeding, the soil surface should be rough and the seedbed should be firm, but neither too loose
nor compacted. The upper layer of soil should be in a condition suitable for seeding at the proper depth
and conducive to plant growth. Seed-to-soil contact is the key to good germination.
Seed Mix for Temporary Vegetation
To provide temporary vegetative cover on disturbed areas which will not be paved, built upon, or fully
landscaped or worked for an extended period (typically 30 days or more), plant an annual grass
appropriate for the time of planting and mulch the planted areas. Annual grasses suitable for the Denver
metropolitan area are listed in Table TS/PS-1. These are to be considered only as general
recommendations when specific design guidance for a particular site is not available. Local governments
typically specify seed mixes appropriate for their jurisdiction.
Seed Mix for Permanent Revegetation
To provide vegetative cover on disturbed areas that have reached final grade, a perennial grass mix should
be established. Permanent seeding should be performed promptly (typically within 14 days) after
reaching final grade. Each site will have different characteristics and a landscape professional or the local
jurisdiction should be contacted to determine the most suitable seed mix for a specific site. In lieu of a
specific recommendation, one of the perennial grass mixes appropriate for site conditions and growth
season listed in Table TS/PS-2 can be used. The pure live seed (PLS) rates of application recommended
in these tables are considered to be absolute minimum rates for seed applied using proper drill-seeding
equipment.
If desired for wildlife habitat or landscape diversity, shrubs such as rubber rabbitbrush (Chrysothamnus
nauseosus), fourwing saltbush (Atriplex canescens) and skunkbrush sumac (Rhus trilobata) could be
added to the upland seedmixes at 0.25, 0.5 and 1 pound PLS/acre, respectively. In riparian zones,
planting root stock of such species as American plum (Prunus americana), woods rose (Rosa woodsii),
plains cottonwood (Populus sargentii), and willow (Populus spp.) may be considered. On non-topsoiled
upland sites, a legume such as Ladak alfalfa at 1 pound PLS/acre can be included as a source of nitrogen
for perennial grasses.
Temporary and Permanent Seeding (TS/PS) EC-2
June 2012 Urban Drainage and Flood Control District TS/PS-3
Urban Storm Drainage Criteria Manual Volume 3
Seeding dates for the highest success probability of perennial species along the Front Range are generally
in the spring from April through early May and in the fall after the first of September until the ground
freezes. If the area is irrigated, seeding may occur in summer months, as well. See Table TS/PS-3 for
appropriate seeding dates.
Table TS/PS-1. Minimum Drill Seeding Rates for Various Temporary Annual Grasses
Speciesa
(Common name)
Growth
Seasonb
Pounds of
Pure Live Seed
(PLS)/acrec
Planting
Depth
(inches)
1. Oats Cool 35 - 50 1 - 2
2. Spring wheat Cool 25 - 35 1 - 2
3. Spring barley Cool 25 - 35 1 - 2
4. Annual ryegrass Cool 10 - 15 ½
5. Millet Warm 3 - 15 ½ - ¾
6. Sudangrass Warm 5–10 ½ - ¾
7. Sorghum Warm 5–10 ½ - ¾
8. Winter wheat Cool 20–35 1 - 2
9. Winter barley Cool 20–35 1 - 2
10. Winter rye Cool 20–35 1 - 2
11. Triticale Cool 25–40 1 - 2
a Successful seeding of annual grass resulting in adequate plant growth will
usually produce enough dead-plant residue to provide protection from
wind and water erosion for an additional year. This assumes that the cover
is not disturbed or mowed closer than 8 inches.
Hydraulic seeding may be substituted for drilling only where slopes are
steeper than 3:1 or where access limitations exist. When hydraulic
seeding is used, hydraulic mulching should be applied as a separate
operation, when practical, to prevent the seeds from being encapsulated in
the mulch.
b See Table TS/PS-3 for seeding dates. Irrigation, if consistently applied,
may extend the use of cool season species during the summer months.
c Seeding rates should be doubled if seed is broadcast, or increased by 50
percent if done using a Brillion Drill or by hydraulic seeding.
EC-2 Temporary and Permanent Seeding (TS/PS)
TS/PS-4 Urban Drainage and Flood Control District June 2012
Urban Storm Drainage Criteria Manual Volume 3
Table TS/PS-2. Minimum Drill Seeding Rates for Perennial Grasses
Common
a
Name
Botanical
Name
Growth
Seasonb
Growth
Form
Seeds/
Pound
Pounds of
PLS/acre
Alakali Soil Seed Mix
Alkali sacaton Sporobolus airoides Cool Bunch 1,750,000 0.25
Basin wildrye Elymus cinereus Cool Bunch 165,000 2.5
Sodar streambank wheatgrass Agropyron riparium 'Sodar' Cool Sod 170,000 2.5
Jose tall wheatgrass Agropyron elongatum 'Jose' Cool Bunch 79,000 7.0
Arriba western wheatgrass Agropyron smithii 'Arriba' Cool Sod 110,000 5.5
Total 17.75
Fertile Loamy Soil Seed Mix
Ephriam crested wheatgrass Agropyron cristatum
'Ephriam' Cool Sod 175,000 2.0
Dural hard fescue Festuca ovina 'duriuscula' Cool Bunch 565,000 1.0
Lincoln smooth brome Bromus inermis leyss
'Lincoln' Cool Sod 130,000 3.0
Sodar streambank wheatgrass Agropyron riparium 'Sodar' Cool Sod 170,000 2.5
Arriba western wheatgrass Agropyron smithii 'Arriba' Cool Sod 110,000 7.0
Total 15.5
High Water Table Soil Seed Mix
Meadow foxtail Alopecurus pratensis Cool Sod 900,000 0.5
Redtop Agrostis alba Warm Open sod 5,000,000 0.25
Reed canarygrass Phalaris arundinacea Cool Sod 68,000 0.5
Lincoln smooth brome Bromus inermis leyss
'Lincoln' Cool Sod 130,000 3.0
Pathfinder switchgrass Panicum virgatum
'Pathfinder' Warm Sod 389,000 1.0
Alkar tall wheatgrass Agropyron elongatum
'Alkar' Cool Bunch 79,000 5.5
Total 10.75
Transition Turf Seed Mixc
Ruebens Canadian bluegrass Poa compressa 'Ruebens' Cool Sod 2,500,000 0.5
Dural hard fescue Festuca ovina 'duriuscula' Cool Bunch 565,000 1.0
Citation perennial ryegrass Lolium perenne 'Citation' Cool Sod 247,000 3.0
Lincoln smooth brome Bromus inermis leyss
'Lincoln' Cool Sod 130,000 3.0
Total 7.5
Temporary and Permanent Seeding (TS/PS) EC-2
June 2012 Urban Drainage and Flood Control District TS/PS-5
Urban Storm Drainage Criteria Manual Volume 3
Table TS/PS-2. Minimum Drill Seeding Rates for Perennial Grasses (cont.)
Common
Name
Botanical
Name
Growth
Seasonb
Growth
Form
Seeds/
Pound
Pounds of
PLS/acre
Sandy Soil Seed Mix
Blue grama Bouteloua gracilis Warm Sod-forming
bunchgrass 825,000 0.5
Camper little bluestem Schizachyrium scoparium
'Camper' Warm Bunch 240,000 1.0
Prairie sandreed Calamovilfa longifolia Warm Open sod 274,000 1.0
Sand dropseed Sporobolus cryptandrus Cool Bunch 5,298,000 0.25
Vaughn sideoats grama Bouteloua curtipendula
'Vaughn' Warm Sod 191,000 2.0
Arriba western wheatgrass Agropyron smithii 'Arriba' Cool Sod 110,000 5.5
Total 10.25
Heavy Clay, Rocky Foothill Seed Mix
Ephriam crested wheatgrass
d
Agropyron cristatum
'Ephriam' Cool Sod 175,000 1.5
Oahe Intermediate wheatgrass Agropyron intermedium
'Oahe' Cool Sod 115,000 5.5
Vaughn sideoats grama
e
Bouteloua curtipendula
'Vaughn' Warm Sod 191,000 2.0
Lincoln smooth brome Bromus inermis leyss
'Lincoln' Cool Sod 130,000 3.0
Arriba western wheatgrass Agropyron smithii 'Arriba' Cool Sod 110,000 5.5
Total 17.5
a All of the above seeding mixes and rates are based on drill seeding followed by crimped straw mulch. These rates should be
doubled if seed is broadcast and should be increased by 50 percent if the seeding is done using a Brillion Drill or is applied
through hydraulic seeding. Hydraulic seeding may be substituted for drilling only where slopes are steeper than 3:1. If
hydraulic seeding is used, hydraulic mulching should be done as a separate operation.
b
See Table TS/PS-3 for seeding dates.
c
If site is to be irrigated, the transition turf seed rates should be doubled.
d
Crested wheatgrass should not be used on slopes steeper than 6H to 1V.
e
Can substitute 0.5 lbs PLS of blue grama for the 2.0 lbs PLS of Vaughn sideoats grama.
EC-2 Temporary and Permanent Seeding (TS/PS)
TS/PS-6 Urban Drainage and Flood Control District June 2012
Urban Storm Drainage Criteria Manual Volume 3
Table TS/PS-3. Seeding Dates for Annual and Perennial Grasses
Annual Grasses
(Numbers in table reference
species in Table TS/PS-1)
Perennial Grasses
Seeding Dates Warm Cool Warm Cool
January 1–March 15
March 16–April 30 4 1,2,3
May 1–May 15 4
May 16–June 30 4,5,6,7
July 1–July 15 5,6,7
July 16–August 31
September 1–September 30 8,9,10,11
October 1–December 31
Mulch
Cover seeded areas with mulch or an appropriate rolled erosion control product to promote establishment
of vegetation. Anchor mulch by crimping, netting or use of a non-toxic tackifier. See the Mulching BMP
Fact Sheet for additional guidance.
Maintenance and Removal
Monitor and observe seeded areas to identify areas of poor growth or areas that fail to germinate. Reseed
and mulch these areas, as needed.
An area that has been permanently seeded should have a good stand of vegetation within one growing
season if irrigated and within three growing seasons without irrigation in Colorado. Reseed portions of
the site that fail to germinate or remain bare after the first growing season.
Seeded areas may require irrigation, particularly during extended dry periods. Targeted weed control may
also be necessary.
Protect seeded areas from construction equipment and vehicle access.
APPENDIX 6
EROSION CONTROL PLANS
National Cooperative Soil Survey
7/11/2013
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