HomeMy WebLinkAboutGARDENS ON SPRING CREEK MAJOR AMENDMENT - FDP - FDP160029 - SUBMITTAL DOCUMENTS - ROUND 1 - EROSION CONTROL LETTER/REPORTEROSION CONTROL REPORT
FOR
GARDENS ON SPRING CREEK
AT
2145 CENTRE AVENUE,
FORT COLLINS, COLORADO
PRESENTED TO
THE CITY OF FORT COLLINS
FORT COLLINS, COLORADO
JUNE 28, 2016
Gardens on Spring Creek - Erosion Control Report Page 1 of 10
TABLE OF CONTENTS
SECTION 1 – GENERAL LOCATION AND DESCRIPTION ................................................................. 2
SITE LOCATION .................................................................................................................... 2
DESCRIPTION OF PROPERTY .................................................................................................. 2
SECTION 2 – DRAINAGE BASINS AND HISTORIC RUNOFF .............................................................. 2
HISTORIC BASINS ................................................................................................................. 3
PROPOSED DEVELOPED BASINS ............................................................................................ 3
SECTION 3 – STORMWATER POLLUTION PREVENTION ................................................................... 4
TEMPORARY EROSION CONTROL .......................................................................................... 4
PERMANENT EROSION CONTROL........................................................................................... 4
STORMWATER MANAGEMENT CONTROLS .............................................................................. 4
SEQUENCE OF CONSTRUCTION ACTIVITIES .............................................................................. 7
SECTION 4 – CONCLUSIONS ..................................................................................................... 9
SECTION 5 – REFERENCES ....................................................................................................... 10
APPENDIX
APPENDIX A – UTILITY PLANS
1. GRADING, DRAINAGE, AND EROSION CONTROL PLAN (C1.0)
2. DETAILED GRADING PLANS (C1.1-1.2)
3. SWMP AND EROSION CONTROL DETAILS (CE1.0)
APPENDIX B – EROSION CONTROL ESCROW/SECURITY CALCULATIONS
APPENDIX C – SOIL DATA FROM NRCS
Gardens on Spring Creek - Erosion Control Report Page 2 of 10
SECTION 1 – GENERAL LOCATION AND
DESCRIPTION
SITE LOCATION
The Gardens on Spring Creek, known as the Community Horticulture Center, is located at 2145
Centre Avenue in the City of Fort Collins, Colorado.
DESCRIPTION OF PROPERTY
The site is owned by the City of Fort Collins, and is made up of a single lot of 18.27 acres. The
existing ground surface is relatively flat, generally sloping either north or south at grades ranging
from 0.5% to 2.0%. The soils within the site consist primarily of Nunn clay loam which have been
classified by the Natural Resources Conservation Services (NRCS) as having a Type C hydrologic
soil group with a slow inflation rate. See Appendix C for soil data. The existing site consists of
the Community Horticulture Center (CHC) and outdoor classrooms, visitor parking lot, Children’s
Garden, Garden of Eatin’, Experiential Garden, and the Rock Garden, all constructed as part of the
first phase of the Master Plan for the development of the City-owned property. In general, as part
of the final buildout of the project (phase 2) on the remaining 5+ acres of undeveloped but native
grassland, proposed improvements include the addition of the Great Lawn and bandstand/stage,
the Prairie Garden, Foothills Garden, Undaunted Garden, extensive trail system expansion, and
enlargement of the stormwater detention pond/Wetlands Demonstration Site to the east. The
existing percent vegetative density of the property is approximately 95%. The rainfall erodibility
is K=0.24 for type C soil and will cause rilling and gulling over longer distances and steeper slopes.
Perimeter control will be the primary means of minimizing the extent of gulling.
There are no irrigation canals passing through the site.
The project site is located in the FEMA 100-year regulatory floodway. Refer to the project
Floodplain Memo prepared by JVA, Inc. dated June 28, 2016 for compliance with Chapter 10 of
City Municipal Code: Flood Prevention and Protection.
Gardens on Spring Creek - Erosion Control Report Page 3 of 10
SECTION 2 – DRAINAGE DESIGN
HISTORIC CONDITION
As discussed in the original approved drainage report titled Center for Advanced Technologies
22
nd
Filing (“Community Horticulture Center”) Final Project Development Drainage and Erosion
Control Report, dated January 31, 2003, prepared by EDAW, Inc. (EDAW), the predeveloped site
historically drained overland directly into Spring Creek. The original storm design by EBAW
mimics the historic drainage pattern; runoff from the site flows via curb & gutter (in the existing
parking lot), grass swales, culverts, and through a perforated underdrain system within the water
quality porous landscape detention areas, ultimately discharging into Spring Creek. The southern
portion of the site is interrupted by the Sherwood Ditch Lateral, and the original suspended CMP
storm culverts were replaced with RCP culverts underneath the ditch to convey runoff into Spring
Creek as part of the phase 1 project. Other than the area immediately adjacent to the Sherwood
Lateral, no runoff will enter the ditch except in the 100-year event.
DEVELOPED CONDITION
The drainage characteristics of the phase 2 buildout of the Gardens on Spring Creek comply with
the original stormwater design intent as described in the approved drainage report and no major
variations are proposed. Runoff will continue to be conveyed to Spring Creek via a combination
of overland flow, vegetated swales, and perforated piping. The existing constructed wetlands basin
(previously referred to as the Wetlands Demonstration Site) will be expanded to approximately
15,000 square feet of area and 0.491 acre-feet of volume. This enlarged basin will encompass and
replace the existing southeastern porous landscape detention (PLD) area (identified as water
quality basin A1a in the original Report) while retaining the existing concrete sill structure and
downstream PLD area to the north, eventually outfalling into Spring Creek. The wetlands basin
will provide 11,843 cubic feet of storage volume above the permanent water surface created by
the concrete sill at an elevation of approximately 4990.94 feet (NAVD88 datum), an increase of
8,149 cubic feet over the existing condition. The small PLD area to the north referred to in the
original plans as basin A1b will also remain. See the attached grading plans, sheets C1.0-C1.2.
EBAW’s Report anticipated the Gardens full buildout by assuming an overall runoff coefficient
value of 0.35 and an approximated 10% imperviousness. Based on as-built drawings of the
Horticulture Center, the existing/post-phase 1 overall site imperviousness was calculated to be
12.5%, with a coefficient of 0.40. The Gardens final proposed layout was calculated to be 17.8%
and 0.44 respectively, resulting in a minor increase over the existing and an insignificant deviation
from the original assumptions. The associated increase in runoff is more than offset by the
increased volume in the constructed wetlands basin.
Gardens on Spring Creek - Erosion Control Report Page 4 of 10
SECTION 3 – STORMWATER POLLUTION
PREVENTION
TEMPORARY EROSION CONTROL
A temporary erosion control plan is to be implemented for the site during construction. Temporary
erosion control measures include, but are not limited to, slope and swale protection provided by
the use of erosion control wattles/sediment control logs, rock socks, erosion control blankets, and
sedimentation basins, etc. All temporary erosion control measures are to be removed after they are
deemed unnecessary. A general erosion control plan has been provided in Appendix A.
PERMANENT EROSION CONTROL
Chapter 2 of the Urban Drainage and Flood Control District’s Urban Storm Drainage Criteria
Manual Volume 3 (USDCM) provides guidelines for the selection of appropriate permanent
structural BMPs for a site that is to be developed or redeveloped. The Gardens on Spring Creek
is best characterized as a “conventional redevelopment” with over 1 acre of impervious area on
the project site. The BMP decision tree for such sites is provided in Figure 2-2 of the USDCM.
As previously stated, the site and surrounding vicinity is comprised of hydrologic soil group Type
C soils, per the NRCS soil survey, with a depth to bedrock of greater than 5 feet. Permeable
pavement (with partial or no infiltration) and/or the use of a “green roof” or grass swale/buffer are
the recommended runoff reduction practices for this scenario. Vegetated swales will perform this
function for the majority of the runoff generated on the site. Treatment and slowed release of the
water quality capture volume occurs at the east and north portion of the property in the existing
porous landscape detention areas and constructed wetlands basin. Since these existing features
facilitate sedimentation and filtering while limiting erosion, and since the existing unchanged use
and limited redevelopment of the site will not subject natural drainageways to increased frequency,
rate, duration, or volume of runoff, the existing measures to reduce water quality and quantity
impacts are sufficient for this site and no additional permanent structural BMP’s are proposed.
STORMWATER MANAGEMENT CONTROLS
The Stormwater Management Plan (SWMP) administrator will be determined at the time the
project is bid for construction.
According to the CDPHE Stormwater Fact Sheet – Construction, construction activities produce
many different kinds of pollutants which may cause stormwater contamination problems. The main
pollutant of concern at construction sites is sediment. Grading activities remove grass, rocks,
pavement, and other protective ground covers, resulting in the exposure of underlying soil to the
elements. The soil is then easily picked up by wind and/or washed away by rain or snowmelt.
Gardens on Spring Creek - Erosion Control Report Page 5 of 10
In addition, construction activities often require the use of toxic or hazardous materials such as
fuel, fertilizers, pesticides, and herbicides, and building materials such as asphalt, sealants, and
concrete, which may also pollute stormwater. These materials can be harmful to humans, plants,
and aquatic life.
There are no known potential pollution sources. However, this condition should be confirmed by
the owner/operator or SWMP administrator. Other pollution sources that could be present include:
runoff from vehicle washing, vehicle maintenance and/or fueling, There are no known existing
non-stormwater components of discharge (i.e., springs, landscape irrigation return flow, and etc.),
or any anticipated during construction.
1. All Disturbed and Stored Soil:
The total disturbed area will be approximately 5.2 acres. Soil stockpiles should be kept
below the locally mandated maximum height of 10 feet and surrounded with sediment
control devices. If the storage of these soils occurs over a period greater than 30 days,
then consider temporarily seeding the soil to minimize soil loss to wind and water
erosion.
2. Vehicle Tracking of Sediments:
The existing site is primarily native grassland and landscaped gardens with an asphalt
parking area and all construction activities will occur within the paved area of the site
or a temporary stabilized stone pad (Vehicle Tracking Control pad, VTC) will be
provided at points of ingress and egress onto the unpaved area. The VTC is designed
to reduce the amount of mud transported onto the public roads by construction traffic.
If the site is extraordinarily muddy, then consider designating an area to wash
construction vehicles before they leave the site and enter the public right-of-way. A
BMP such as this is a good way to avoid the costs associated with street cleaning or
accidentally discharging large amounts of sediment into other storm drain systems.
When in doubt, choose methods that prevent pollution rather than ones that force
clean-up at the downstream end just before the stormwater enters the receiving
waters. In other words, the most efficient construction site BMPs are those that
prevent erosion from happening.
3. Inlet Protection (IP): gravel inlet protection will be used on all existing downstream
inlets to prevent sediment and debris from entering the storm drain system.
4. Street sweeping will be conducted as necessary to remove sediment tracked on to
pavement and adjacent streets.
5. Management of Contaminated Soils:
There are no know contaminated soils on site. If contaminated soils are found, the
contractor shall report to the SWMP administrator.
Gardens on Spring Creek - Erosion Control Report Page 6 of 10
6. Loading and Unloading Operations:
The existing entrance to the site is currently paved and loading/unloading activities
will occur within the paved area of the site or a temporary gravel staging area will be
provided.
7. Outdoor Storage Activities:
Materials storage, waste disposal, and vehicle maintenance and fueling can occur
within an enclosed and secure area.
8. Vehicle and Equipment Maintenance and Fueling:
Materials should be stored and handled in covered areas to prevent contact with
stormwater, and chemicals should be stored within berms or secondary containment
devices to prevent leaks and spills from entering stormwater runoff.
Spill Management
In general, spill prevention and response should include the following:
a) Notification procedures to be used in the event of an accident. At the very
least, the SWMP Administrator should be notified. Depending on the nature
of the spill and the material involved, the Colorado Department of Health,
downstream water users, or other agencies may also need to be notified.
b) Instructions for clean-up procedures.
c) Provisions for absorbents are to be made available for use in fuel areas, and
for containers to be available for used absorbents.
d) Procedures for properly washing out concrete trucks and other equipment in a
manner and location so that the materials and wash water cannot discharge
from the site, and never into a storm drain system or stream.
9. Significant Dust or Particulate Generating Processes:
Disturbed areas not yet ready to be seeded, landscaped, paved, or otherwise stabilized
shall be watered, or ripped as necessary to preclude visible dust emissions. Contractor
shall make every effort to minimize particulate emissions from vehicles performing the
work, including but not limited to regular maintenance of construction equipment.
10. Routine Maintenance Activates Involving Fertilizer, Pesticides, Detergents, Fuels,
Solvents, Oils, Etc:
Materials should be stored and handled in covered areas to prevent contact with
stormwater, and chemicals should be stored within berms or secondary containment
devices to prevent leaks and spills from entering stormwater runoff.
11. On-site Waste management Practices (Waste Piles, Liquid Wastes, Dumpsters, etc):
Materials storage, waste disposal, and vehicle maintenance and fueling can occur
within an enclosed and secure area. The area can be enclosed with temporary fencing
and accessed through a gate with a lock.
Gardens on Spring Creek - Erosion Control Report Page 7 of 10
12. Concrete Truck/Equipment Washing:
A concrete washout facility will be provided onsite. Properly wash out concrete trucks
and other equipment in a manner and location (a minimum of 50 feet away from any
inlet structures) so that the materials and wash water cannot discharge from the site,
and never into a storm drain system or stream.
13. Dedicated Asphalt and Concrete Batch Plants:
There will be no dedicated batch plant on site.
14. Non-Industrial Waste Source Such as Workers Trash And Portable Toilets:
Garbage cans shall be located at break areas and portable toilets shall be provided if
onsite bathroom facilities cannot be used. Locate dumpsters and portable toilets away
from drainage courses (minimum 50 feet from any inlet structures) and stake down
toilets to prevent tipping.
15. Other Areas or Procedures where Potential Spills can Occur:
Records of spills, leaks, or overflows that result in the discharge of pollutants must be
documented and maintained. Record all spills that are responded to, even if they do
not result in a discharge of pollutants. Information that should be recorded for all
occurrences includes the time and date, weather conditions, reasons for the spill, etc.
Some spills may need to be reported to immediately. Specifically, a release of any
chemical, oil, petroleum product, sewage, etc., which may enter waters of the State of
Colorado (which include surface water, ground water and dry gullies or storm sewers
leading to surface water) must be reported. More guidance is available on the web at
www.colorado.gov. The Division’s toll-free 24-hour number for environmental
hazards and chemical spills and releases is 1-877-518-5608.
SEQUENCE OF CONSTRUCTION ACTIVITIES
Construction Start Date (This is the day you expect to begin disturbing soils, including grubbing,
stockpiling, excavating, demolition, and grading activities): October 1, 2016.
Final Stabilization Date (this is when the site is finally stabilized. This means that all disturbed
areas have been either built on, paved, or a uniform vegetative cover reaching over 70% of the
initial vegetative density has been established.) Even if you are doing one part of the project, the
estimated completion date must be for the overall project: May 31, 2018.
Construction Sequencing: (Detailed construction sequencing to be determined by the contractor)
1. Installation of temporary erosion and sediment control measures.
This includes all sediment control logs, rock socks, erosion control blankets, and silt fence
where all land disturbing activities will occur.
2. Sequence of all land disturbing activity.
Overlot grading in preparation for the pouring of new sidewalks will occur early in the
construction schedule. Additional land disturbance will occur around the site for utility
installation and the construction of the new bandstand/stage structure.
Gardens on Spring Creek - Erosion Control Report Page 8 of 10
3. Drainage facility construction.
No new drainage facilities are proposed for this project.
4. Sediment basins, temporary channel stabilization.
The expanded wetlands basin will be utilized as a temporary sediment basin while erosion
control blankets will be installed on the banks of the vegetated swale running through the
site.
5. Seeding
All disturbed areas will be seeded upon completing of finish grading. Refer to the landscape
plans for detailed planting and seeding schedule.
6. Mulching.
Spread straw mulch uniformly over seeded areas at a rate of 90 lbs per 1000 square feet of
ground. No more than 25% of the ground should be visible. Crimp or pinch mulch into
soil 2-4 inches by using either a mulch anchoring tool, a farm disk operating on the contour
of the slope, or by cleating with bulldozer tracks operating up and down the slopes (to
prevent tracks from forming gullies).
7. Required maintenance activities (e.g. after-storm checks of all BMPs, etc.).
All temporary sediment control BMPs shall be inspected after each rain event to ensure
proper protection and to determine if cleaning is necessary. Final cleaning of all storm
facilities shall be provided upon final stabilization of site.
Gardens on Spring Creek - Erosion Control Report Page 9 of 10
SECTION 4 – CONCLUSIONS
The goal of the erosion control report is to describe appropriate controls and measures to
improve water quality by reducing pollutants in stormwater discharges and ensure compliance
with the requirements of the City of Fort Collins Erosion Control Standards.
The proposed improvements for the Gardens on Spring Creek will slightly increase the overall
imperviousness of the site over the existing condition. However, total storm water runoff
discharging into Spring Creek was anticipated with the first phase of the Community
Horticulture Center and the final phase of improvements will accommodate the minor increase of
the original assumption by increasing the capacity of the wetlands basin to capture and treat
runoff before it leaves the site. Both the existing and proposed permanent structural BMP’s on
site, including the vegetated swales and porous landscape detention areas, capture the majority of
the runoff discharged from the site and improve storm water quality by facilitating sedimentation
and filtering while limiting erosion through slowed-release of runoff.
Temporary BMP’s to be employed during the construction of the proposed improvements
include straw wattles and rock socks at the downstream limits of disturbance, slope protection on
the vegetated swale, a concrete washout facility on site, street sweeping practices to eliminate
tracked sediment, and construction of a temporary sedimentation basin in the proposed wetlands
basin.
These measures, along with the other standard Best Management Practices described in this
report, will serve to reduce pollutants in the storm water runoff and satisfy the requirements of
the City of Fort Collins Erosion Control Standards.
Gardens on Spring Creek - Erosion Control Report Page 10 of 10
SECTION 5 – REFERENCES
1. Urban Storm Drainage Criteria Manual (Volumes 1, 2, and 3), Urban Drainage and Flood
Control District, June 2001, Revised April 2008.
2. Storm Drainage Criteria Manual and Construction Standards, City of Fort Collins Storm
Water Utility, City of Fort Collins, Colorado, Updated January, 1997 with 2012
amendments.
3. “Hydrologic Group Rating for Larimer County Area, Colorado”, USDA-Natural
Resources Conservation Service, National Cooperative Soil Survey. Web Soil Survey
URL: http://websoilsurvey.nrcs.usda.gov. [09/03/2015]
APPENDIX A – UTILITY PLANS
1. Grading, Drainage, and Erosion Control Plan (C1.0)
2. Detailed Grading Plans (C1.1-1.2)
3. SWMP and Erosion Control Details (CE1.0)
SHEET NUMBER
C JVA, INC
DATE:
JOB NUMBER:
CHECKED BY:
DRAWN BY:
DESIGNED BY:
NO. DATE DRAWN DESIGNED REVISION / ISSUE DESCRIPTION
JVA, Incorporated 25 Old Town Square
Suite 200 Fort Collins, CO 80524
E-mail: info@jvajva.com
Phone: 970.225.9099 Fax: 970.225.6963
CONSULTING ENGINEERS
CENTRE FOR ADVANCED TECHNOLOGY 22ND FILING
COMMUNITY HORTICULTURE CENTER
MAJOR AMENDMENT - FINAL UTILITY PLANS
2257c
JUNE 2016
BJC
KRB
CRH
GRADING, DRAINAGE, AND EROSION CONTROL PLAN
C1.0
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Date
Date
Date
Date
Date
Date
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Parks and Recreation
Traffic Engineer
Stormwater Utility
Water & Wastewater Utility
City Engineer
CHECKED BY:
APPROVED:
Date
Environmental Planner
SHEET NUMBER
C JVA, INC
DATE:
JOB NUMBER:
CHECKED BY:
DRAWN BY:
DESIGNED BY:
NO. DATE DRAWN DESIGNED REVISION / ISSUE DESCRIPTION
JVA, Incorporated 25 Old Town Square
Suite 200 Fort Collins, CO 80524
E-mail: info@jvajva.com
Phone: 970.225.9099 Fax: 970.225.6963
CONSULTING ENGINEERS
CENTRE FOR ADVANCED TECHNOLOGY 22ND FILING
COMMUNITY HORTICULTURE CENTER
MAJOR AMENDMENT - FINAL UTILITY PLANS
2257c
JUNE 2016
BJC
KRB
CRH
DETAILED GRADING PLAN - WEST
C1.1
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Date
Date
Date
Date
Date
Date
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Parks and Recreation
Traffic Engineer
Stormwater Utility
Water & Wastewater Utility
City Engineer
CHECKED BY:
APPROVED:
Date
Environmental Planner
SHEET NUMBER
C JVA, INC
DATE:
JOB NUMBER:
CHECKED BY:
DRAWN BY:
DESIGNED BY:
NO. DATE DRAWN DESIGNED REVISION / ISSUE DESCRIPTION
JVA, Incorporated 25 Old Town Square
Suite 200 Fort Collins, CO 80524
E-mail: info@jvajva.com
Phone: 970.225.9099 Fax: 970.225.6963
CONSULTING ENGINEERS
CENTRE FOR ADVANCED TECHNOLOGY 22ND FILING
COMMUNITY HORTICULTURE CENTER
MAJOR AMENDMENT - FINAL UTILITY PLANS
2257c
JUNE 2016
BJC
KRB
CRH
DETAILED GRADING PLAN - EAST
C1.2
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Date
Date
Date
Date
Date
Date
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Parks and Recreation
Traffic Engineer
Stormwater Utility
Water & Wastewater Utility
City Engineer
CHECKED BY:
APPROVED:
Date
Environmental Planner
SHEET NUMBER
C JVA, INC
DATE:
JOB NUMBER:
CHECKED BY:
DRAWN BY:
DESIGNED BY:
NO. DATE DRAWN DESIGNED REVISION / ISSUE DESCRIPTION
JVA, Incorporated 25 Old Town Square
Suite 200 Fort Collins, CO 80524
E-mail: info@jvajva.com
Phone: 970.225.9099 Fax: 970.225.6963
CONSULTING ENGINEERS
CENTRE FOR ADVANCED TECHNOLOGY 22ND FILING
COMMUNITY HORTICULTURE CENTER
MAJOR AMENDMENT - FINAL UTILITY PLANS
2257c
JUNE 2016
BJC
KRB
CRH
SWMP & EROSION CONTROL DETAILS
CE1.0
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Date
Date
Date
Date
Date
Date
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Parks and Recreation
Traffic Engineer
Stormwater Utility
Water & Wastewater Utility
City Engineer
CHECKED BY:
APPROVED:
Date
Environmental Planner
APPENDIX B – EROSION CONTROL ESCROW
9/9/2015
Project: Disturbed Acres: 5.20
EROSION CONTROL BMPs Units
Estimated
Quantity
Unit
Price
Total
Price
each 1 $750.00 $750.00
each 8 $150.00 $1,200.00
L.F. 1000 $2.00 $2,000.00
each 2 $1,500.00 $3,000.00
LS 1 $2,000.00 $2,000.00
Sub-Total: $8,950.00
1.5 x Sub-Total: $13,425.00
Amount of security: $13,425.00
AC 2.6 $2,000.00 $5,200.00
Sub-Total: $5,200.00
1.5 x Sub-Total: $7,800.00
Amount to Re-seed: $7,800.00
Minimum escrow amount: $3,000.00
Erosion Control Escrow: $13,425.00
Erosion and Sediment Control Escrow/Security Calculation
for The City of Fort Collins
BMP Amount
Vehicle Tracking Control Pad
Temporary Sedimentation Basin
Street Sweeping and Cleaning
Reseeding Amount
Sediment Control Log
Miniumum Escrow Amount
Gardens on Spring Creek
Seeding
“The amount of the security must be based on one and one-half times the estimate of the cost to install the approved measures, or one and one-half times
the cost to re-vegetate the disturbed land to dry land grasses based upon unit cost determined by the City's Annual Revegetation and Stabilization Bid,
whichever is greater. In no instance, will the amount of security be less than one thousand five hundred dollars ($1,500) for residential development or
three thousand dollars ($3,000) for commercial development”
Rock Sock
Final Escrow Amount (Maximum between BMP, Reseeding and Minimum Escrow)
9/16/2015 11:36 AM V:\2257c Gardens on Spring Creek\Reports\Erosion Control Report\Feeders Supply Erosion Control Escrow (2014-08-19).xls
APPENDIX C – SOIL DATA FROM NRCS
Hydrologic Soil Group—Larimer County Area, Colorado
(Gardens on Spring Creek)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
9/8/2015
Page 1 of 4
4489940 4490000 4490060 4490120 4490180 4490240 4490300 4490360 4490420
4489940 4490000 4490060 4490120 4490180 4490240 4490300 4490360 4490420
492620 492680 492740 492800 492860 492920 492980
492620 492680 492740 492800 492860 492920 492980
40° 33' 52'' N
105° 5' 14'' W
40° 33' 52'' N
105° 4' 58'' W
40° 33' 36'' N
105° 5' 14'' W
40° 33' 36'' N
105° 4' 58'' W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 100 200 400 600
Feet
0 35 70 140 210
Meters
Map Scale: 1:2,440 if printed on A portrait (8.5" x 11") sheet.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more accurate
calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
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
4 Altvan-Satanta loams, 3
to 9 percent slopes
B 0.1 0.7%
22 Caruso clay loam, 0 to 1
percent slope
D 1.7 10.3%
76 Nunn clay loam, wet, 1 to
3 percent slopes
C 12.0 74.5%
81 Paoli fine sandy loam, 0
to 1 percent slopes
A 2.3 14.5%
Totals for Area of Interest 16.1 100.0%
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.
Hydrologic Soil Group—Larimer County Area, Colorado Gardens on Spring Creek
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
9/8/2015
Page 3 of 4
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—Larimer County Area, Colorado Gardens on Spring Creek
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
9/8/2015
Page 4 of 4
K Factor, Whole Soil—Larimer County Area, Colorado
(Gardens on Spring Creek)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
9/8/2015
Page 1 of 3
4489940 4490000 4490060 4490120 4490180 4490240 4490300 4490360 4490420
4489940 4490000 4490060 4490120 4490180 4490240 4490300 4490360 4490420
492620 492680 492740 492800 492860 492920 492980
492620 492680 492740 492800 492860 492920 492980
40° 33' 52'' N
105° 5' 14'' W
40° 33' 52'' N
105° 4' 58'' W
40° 33' 36'' N
105° 5' 14'' W
40° 33' 36'' N
105° 4' 58'' W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 100 200 400 600
Feet
0 35 70 140 210
Meters
Map Scale: 1:2,440 if printed on A portrait (8.5" x 11") sheet.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
.02
.05
.10
.15
.17
.20
.24
.28
.32
.37
.43
.49
.55
.64
Not rated or not available
Soil Rating Lines
.02
.05
.10
.15
.17
.20
.24
.28
.32
.37
.43
.49
.55
.64
Not rated or not available
Soil Rating Points
.02
.05
.10
.15
.17
.20
.24
.28
.32
.37
.43
.49
.55
.64
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
K Factor, Whole Soil
K Factor, Whole Soil— Summary by Map Unit — Larimer County Area, Colorado (CO644)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
4 Altvan-Satanta loams, 3
to 9 percent slopes
.28 0.1 0.7%
22 Caruso clay loam, 0 to 1
percent slope
.32 1.7 10.3%
76 Nunn clay loam, wet, 1 to
3 percent slopes
.24 12.0 74.5%
81 Paoli fine sandy loam, 0
to 1 percent slopes
.15 2.3 14.5%
Totals for Area of Interest 16.1 100.0%
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 Kw (whole soil)" indicates the erodibility of the whole soil. The
estimates are modified by the presence of rock fragments.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Layer Options (Horizon Aggregation Method): Surface Layer (Not applicable)
K Factor, Whole Soil—Larimer County Area, Colorado Gardens on Spring Creek
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
9/8/2015
Page 3 of 3
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 9, Sep 22, 2014
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Apr 22, 2011—Apr
28, 2011
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
K Factor, Whole Soil—Larimer County Area, Colorado
(Gardens on Spring Creek)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
9/8/2015
Page 2 of 3
Survey Area Data: Version 9, Sep 22, 2014
Soil map units are labeled (as space allows) for map scales 1:50,000
or larger.
Date(s) aerial images were photographed: Apr 22, 2011—Apr 28,
2011
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Hydrologic Soil Group—Larimer County Area, Colorado
(Gardens on Spring Creek)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
9/8/2015
Page 2 of 4