HomeMy WebLinkAboutStormwater Mangement PlanWright Water Engineers, Inc.
818 Colorado Avenue, P.O. Box 219
Glenwood Springs, Colorado 81602
970-945-7755 Tel • 970-945-1608 Fax
TO Garfield County
Community Development Department
108 8'" Street, Suite 401
Glenwood Springs, CO 81601
WE ARE SENDING YOU
LETTER OF TRANSMITTAL
DATE JOB NO
December 15, 2015 151-102.000
ATTENTION
Andy Schwaller
RE ,.
Rifle Ute 230.345 kV Substation Project
0 Attached 0 Under Separate cover via
❑ Shop drawings 0 Prints 0 Plans
❑ Copy of Letter 0 Change Order 0
0 Samples
the following items:
0 Specifications
COPIES
DATE
NO.
DESCRIPTION
1
12/14/15
❑ As requested
Grading Permit Application
1
12/11/15
82265
Check for Grading Permit Fee ($400)
1
12/2015
Construction Stormwater Management Plan (SWMP)
THESE ARE TRANSMITTED as checked below.
El For approval
1 0 Approved as submitted
0 Resubmit _ copies for approval
El For your use
0 Approved as noted
0 Submit _ copies for distribution
❑ As requested
0 Returned for corrections
0 Return _ corrected prints
❑ For review and comment
0
❑ FOR BID DUE 0 PRINTS RETURNED AFTER LOAN TO US
REMARKS:
Enclosed.
COPY TO
SIGNED: Jennifer Keyes
If enclosures am not as noted, kindly notify us at once.
INTRODUCTION
This is a Stormwater Management Plan (SWMP) for the Rifle Ute 230/345 kV Substation Project
being conducted by Public Service Company of Colorado (PSCo), a Colorado corporation and an
Xcel Energy Company. This document has been developed as defined in the Colorado
Discharge Permit System (CDPS) General Permit for Stormwater Discharges Associated With
Construction Activity (Permit No. COR -030000, effective July 1, 2007) authorizing stormwater
discharges from construction activities that result in a total land disturbance of one acre or greater
or if a project is less than an acre but part of a larger common plan of development. This SWMP
was also developed to meet Garfield County grading and stormwater permitting requirements.
Garfield County regulates stormwater through their grading permit program. Although the site's
address is in Rifle the site is outside of the town's limits and is located in Unincorporated Garfield
County.
For the purposes of consistency with the state and local requirements, this SWMP will be referred
to as a SWMP but it has been designed to also meet all of the County's grading, erosion and
sediment control requirements.
This SWMP was prepared in accordance with good engineering, hydrologic and pollution control
practices. Changes or additions may be required to address changes in conditions at the project
If such changes are made, this SWMP will be updated accordingly.
The overall purpose of this SWMP is to:
• Identify all potential sources of pollution which may reasonably be expected to affect the
quality of stormwater discharges associated with construction activity from the project;
• Describe the practices to be used to reduce the pollutants in stormwater discharges
associated with construction activity at the project;
• Ensure the practices are selected and described in accordance with good engineering
practices, including the installation, implementation and maintenance requirements; and
• Be implemented as written and updated, from commencement of construction activity
until final stabilization is complete: as a condition of the permit.
1. SITE DESCRIPTION (§I.C.1)
A. Nature of the construction activity at the site (Permit Section (S) I.C.1.a):
This SWMP covers construction activities associated with new facilities and electrical
features to be installed within the existing 230 kV yard of the existing Rifle Ute
Substation. This work includes installing new underground lines via trenching and
excavations for new foundations for the new electrical structures. The work in the
substation is being done as part of the work needed to accommodate the new 230 kV
transmission line that will be installed in the spring of 2016 between the Rifle Ute
Substation and the Parachute Substation. The transmission work will be permitted
separately and is not part of this SWMP.
In addition to the electrical features, PSCo and their contractors will be relocating the
northwestern portion of the existing access road within the 230 kV yard of the substation
to accommodate the new electrical features. The existing fence in this area is not
anticipated to be moved although the gate may be moved to accommodate the new road
alignment. A designated staging area will be established along the northeastern portion
of the site, within the boundaries of the existing 230 kV yard within the substation. The
location may be modified in the field after the contractor for this work is determined. This
staging area is anticipated to include a construction trailer, concrete washout, stockpile
area, portable toilets, and potentially a dumpster. The gravel may be scraped off portions
of the staging area especially where stockpiles may be stored, Following construction.
the area used for the staging area will be restored to a gravel surface, as it exists today.
Upon completion of earth disturbing activities, the substation will be stabilized with road
base and gravel, as shown on the site drawings and disturbed areas outside of the active
substation will have rock placed on the limited fill slopes. All disturbed areas will be
stabilized with a hard, non-erosive surface, there are no plans to seed any areas at this
time.
The site lies approximately 880 feet south of County Rd 319, 0.5 miles south of 1-70, and
southeast of Rifle, Colorado in unincorporated Garfield County. PSCo owns and
operates three yards associated with the Rifle Ute Substation. One is referred to as the
230 Yard and is located in the northwest portion of the property, the second yard which is
referred to as the 345 yard is located immediately south of the 230 kV yard and the third
yard is referred to as the 138/69/24.9 kV yard. All of the proposed work is associated
with the 230 kV yard. The area surrounding these electrical substation yards contain
undeveloped, open land. The approximate latitude and longitude for the middle of the
project covered by this SWMP and associated permits is 38°31'17.18"N,
107°44'28.48'W, respectively.
Appropriate BMPs will be used to minimize the impact of earth disturbing activities as
shown on the site plans in Tab 2.
B. The proposed sequence for major activities (41.C.1.bi:
Estimated Project Start Date: 3/1/2016 — Substation
Estimated End of Construction Date: 9/16/2016
Estimated Final Stabilization Date: 10/1/2016 — Disturbed areas will be stabilized
with gravel and rock
The project will generally adhere to the following sequence for major activities:
Pre -construction —The Project is designed and site visits are arranged to determine site
specific BMPs, pre -construction vegetative cover, and existing drainagesfoutfalls. These
features are then incorporated in site-specific BMP maps and used to develop this
SWMP. The SWMP is a dynamic document that will continuously be modified during this
Project. Site perimeter sediment controls are required prior to initial disturbance.
Potholing may also occur prior to construction in order to determine existing utility
locations. BMPs including perimeter controls (if they have not already been installed) will
be utilized while there are active potholing activities.
Construction - Construction activities are expected to follow the sequence outlined below
• Install a vehicle tracking control pad at proposed access point as indicated on the
site drawing if the access road is not appropriately stabilized for construction
traffic. The existing yards and roads are currently graveled.
• Install perimeter control (primarily rock socks and sediment control logs) around
the downgradient side of the proposed area where access road will be realigned
and work areas associated with new foundations and underground lines. Rock
C61414U1
socks or equivalent (e.g. Big Reds®) will be used around stockpiles within the
substation.
• Bring construction material onsite and set up the staging area within the 230 kV
yard of the substation. The staging area location maybe modified in the field and
will include construction trailers, portable toilets, at least one concrete washout,
spoil piles and potentially a dumpster.
• Excavate for new foundations. Excavated material may be used for fill
associated with the realigned access road.
• Place fill material as needed for the realigned access road.
• Stabilize the fill slopes with appropriately sized rock.
• The VTC may need to be relocated once the realigned road is in place.
• Install new features within the existing substation.
• Excavated trenches associated with the underground utilities. The trenches are
anticipated to be approximately 5 feet deep and between 1 to 2 feet wide. Spoils
will either be stockpiled upgradient of the trench as feasible or in the staging
area. Perimeter controls will be installed around stockpiled materials or the
stockpiles will be located in an area with perimeter controls.
• Install new utility lines and backfill using excavated materials.
• Install road base and gravel as needed on any surfaces that were disturbed as
part of this construction within the substation yard.
• Remove temporary BMPs that are no longer required.
• Close out permits.
Post -construction - BMPs will be maintained or modified as needed until final stabilization
is achieved. The site-specific figures will be updated to reflect field conditions. After
construction has been completed and final stabilization is achieved, all temporary non -
biodegradable BMPs will be removed and all appropriate forms will be completed and
sent to the applicable regulatory agencies.
C. Disturbed area (§I.C.1.c):
1. Total area of property:
2. Total area of construction site:
3. Total area of disturbance:
— 65 acres
3.02 acres
1.68 acres (Transmission Project will be
permitted separately)
4. Acreage of seeding: None
D. Existing Soil Data (41.C.1.d1:
The soils on-site are described by the NRCS to be Arvada loam, 6 to 20 percent slopes,
and are classified as Hydrologic Soil Type C with an erosion factor (Kt) of 0.32 which is
moderate. See tab 15 for the full soil report.
E. Existing Vegetation (4I.C.1.4
There is no existing vegetation in the existing substation yards, including the 230 yard,
where all of the construction will be occurring. There is limited vegetation along the
western side of the 230 yard where the access road will be realigned. The vegetation in
this area is patchy with some grasses and shrubs with a vegetative cover of
approximately 35-40 %. Once the road is realigned, this area will be part of the road or
be rocked.
Pre -construction photos of the project area are documented in Tab 12.
There are no anticipated impacts to wetlands associated with this project.
F. Potential Pollution Sources ($I.C.1.fl:
The location and description of all potential pollution sources, including ground surface
disturbing activities, are described in Tab 4 of this SWMP.
G. Allowable Non-stormwater Discharges ((4I.C.1.q),(4I.D.31, and ($1.C.3.c.8 1:
Except as provided in the paragraphs below, all discharges that occur during the life of
this project shall be composed entirely of stormwater associated with construction
activity.
The Colorado Discharge Permit System (CDPS) General Permit allows the following non-
stormwater discharges in combination with stormwater discharges associated with
construction sites, provided that the non-stormwater component of the discharge is
identified in the SWMP:
• Discharges from fire -fighting activities;
• Natural springs;
• Landscape irrigation return flow;
• Discharges to the ground of concrete washout water from washing of tools and
concrete mixer chutes are allowed under this SWMP, provided that: the washout
water is confined in a concrete washout area and does not leave the site as
surface runoff or to surface waters, and does not enter groundwater.
• Certain construction dewatering discharges. The WQCD's General Permit for
Stormwater Discharges from Construction Activities allows for dewatering of
groundwater and stormwater to the ground surface to allow for infiltration on the
site. No groundwater from construction dewatering will be discharged as surface
runoff or to surface waters on the site. It is not anticipated that dewatering
activities will be required during this project. However if dewatering becomes
necessary, groundwater and/or stormwater may be pumped from excavations or
trenches to the ground surface on the site for infiltration or evaporation. The
location of pumping and deposition of the groundwater or stormwater will be
marked on the site plan prior to the start of pumping activities. If it becomes
necessary to pump groundwater off site or into a waterway or storm sewer, then
a groundwater discharge permit must be obtained from the State prior to
engaging such activities.
Discharges of material other than stormwater must be addressed in a separate Colorado
Discharge Permit System (CDPS) permit issued for that discharge. There are no
anticipated additional discharges associated with this project. Copies of environmental
permits for this project are in Tab 13.
H. Receiving Waters (61.C.1.h1:
1. Outfall locations:
Location
Size
Type
Receiving Waters
39°31'16.90"N,
107°44'31.40" W
- 24
CMP
Swale that drains to Dry Creek, a tributary
to Colorado River
Northwest corner of
project area,
northern and
eastern sides of the
project area
NIA
Sheet flow
Dry Creek, a tributary to Colorado River
2. Names of receiving water(s) on site and the ultimate receiving water: Dry Creek, a
tributary to the Colorado River is located approximately 450 feet east of the
substation. There are also several drainage swales with the PSCo substation
property that drain to another unnamed tributary that ultimately drains to Dry Creek
and then the Colorado River.
3. Distance ultimate receiving water is from project: Dry Creek is approximately 450
feet from the project. The Colorado River is approximately 0.8 miles to the north of
the project.
4. Does the receiving water have an approved TMDL: No, this portion of the Colorado
River is COLCLC01 which is monitored for sediment but is not listed nor are its
tributaries listed as impaired or having a TMDL.
1. Site Map (I.C.2)
The SWMP shall include a legible site map(s), showing the entire site, identifying:
a) Construction site boundaries;
b) All areas of ground surface disturbance;
c) Areas of cut and fill
d) Areas used for storage of building materials, equipment, soil, or waste;
e) Locations of dedicated asphalt or concrete batch plants;
f) Locations of all structural BMPs;
g) Locations of all non-structural BMPs as applicable; and
h) Locations of springs, streams, wetlands and other surface waters (include all
conveyance systems including inlets, outfalls, drainage swales, and detention ponds
etc.)
SWMP Administrator (§I.C.3.a):
The PSCo SWMP Administrator is responsible for overseeing and/or assigning PSCo personnel,
consultants, and/or contractors to aid in the development, implementation, maintenance, and
revisions to the SWMP. PSCo's SWMP Administrator designates a Site Stormwater Manager for
each project who is responsible for day to day SWMP compliance at the site. The PSCo SWMP
Administrator and other contact information for this project are indicated below:
Contact Information
PSCo Environmental Services:
Name: Rebecca Sturgeon
Title: Environmental Analyst
Address: 1800 Larimer Street, Suite 1300,
Denver, CO 80202
Phone: 303-294-2189
Email: Rebecca.sturgeon(8 xcelenernv.com
SWMP Administrator: TBD
Name: David Vara
Title: Construction Project Manager
Address: 9500 1-76, Henderson, CO 80640
Phone: 303-628-2809
Email: David.r.vara@xcelenergy.com
Alternate SWMP Administrator:
Name: Rebecca Sturgeon
Company: Public Service Company of
Colorado
Address: 1800 Larimer Street, Suite 1300
Phone: 303-294-2189
Email: Rebecca.sturgeon@xcelenergy.com
Project Manaberisl:
Name: Don Simpson
Title: Substation Project Manager
Address: 1800 Larimer Street, Ste 500,
Denver, CO 80202
Phone: 303-571-7771
Email: don.simpson@xcelenergy.com
Name: George Sanders
Title: Transmissions Project Manager
Address: 1800 Larimer Street, Ste 500,
Denver, CO 80202
Phone: 303.294-2725
Email: George.w.sanders@xcelenergy.com
SWMP and Erosion and Sediment
Control Plan Prepared bv:
Name: Jennifer Keyes, CPESC
Company: Wright Water Engineers, Inc.
Address: 2490 W.261h Ave, Suite 100A
Denver, CO 80211
Phone: 303-480-1700
Email: jkevesl8 wrinhtwater.com
Project Foreman: TBD
Substation:
Name
Company
Address
Phone
Email
SWMP Inspector:
Name: TBD
Company: Summit Services
Address: 7796 E. Napa PI, Denver, CO
80237
Phone: 303-500-2454
Email
BMP Implementation: TBD
Name:
Company:
Address:
Denver:
Phone:
Email:
Phased BMP Implementation (§I.C.3.c)3)
The following section describes the BMPs selected for implementation on this site. Specific locations of
BMPs are indicated on the site plans, provided in Tab 2. Installation, implementation and maintenance
specifications for each BMP are included in Tab 6.
Minimize disturbed area and protect natural features:
The project will be phased to the extent practical to limit the amount of disturbed area that is exposed at
any given time. BMP phasing is critical to stormwater management. BMP implementation will be
coordinated with the various stages of construction. BMPs that control erosion and sediment transport
from initial site activities will be installed prior to earth disturbing activities. As work progresses and
additional areas are disturbed, BMPs that control erosion and sediment transport will be implemented
prior to start of earth disturbing activities in those areas. As portions of the site are completed and
previously disturbed areas are stabilized or the BMP is no longer needed, BMPs will be removed.
Permanent or temporary soil erosion control measures for all slopes, channels, ditches, or any disturbed
land area and soil stockpiles, will be implemented as soon as practicable after final grading or the final
earth disturbance has been completed. When it is not possible to permanently stabilize a disturbed area
after an earth disturbance has been completed or where significant earth disturbance activity ceases,
temporary erosion control measures will be implemented as soon as practicable.
Project Phase
BMPs to be Implemented during each phase*
Pre-Disturbance/Site Preparation
• Pothole as needed using appropriate BMPs (Perimeter
control around the pothole if the hole in not in a contained
area).
• Install a VTC near the northwest corner of the 230 yard or
before the gravel access road becomes a paved, private
access road.
• Install perimeter controls around the northern, eastern and
western sides of the 230 yard..
• Establish the staging area including the concrete washout,
trailers, portable toilets, stock spoil pile area, and potentially
a dum ester etc.
Construction
• Bring material and equipment onsite.
• Locate stockpiles in work areas with perimeter BMPs or
install a control measure at the toe of the stockpile.
• Substation work will consist of multiple projects including
realigning the access road, installing new foundations,
limited grading (which is mostly associated with the
realigned access road), installing new facilities, and installing
new underground electrical lines via trenching.
• Protect and repair BMPs, as necessary.
• Perform street sweeping, as needed during all active phases
of construction. The distance of the access road from the
public, paved street to the work area is anticipated to be the
primary BMP for minimizing the potential for tracking;
however, VTC will also be installed between the paved,
private access drive and the work area.
• The VTC may need to move once the realigned road work is
completed.
Backfill and Compacting
• Leave disturbed area of site in a surface roughened
condition when feasible.
• Close excavations as soon as possible.
• Remove temporary BMPs where appropriate.
Specific details/specifications regarding the implementation and maintenance of each BMP type are provided in Tab 6
• Remove limited stored materials and equipment from the
site.
Final Stabilization
• Spread road base and gravel in disturbed areas within the
230 yard portion of the substation and on the realigned
access road.
• Install appropriately sized rock where called out for on the
site plans.
• Spread road base and gravel in any areas not already
stabilized.
• Remove all non-biode.radable temporary BMPs.
Specific details/specifications regarding the implementation and maintenance of each BMP type are provided in Tab 6
Final Stabilization (§I.C.4.)
Description of Final Stabilization Practices (4I.C.4.a)
Upon completion of earth disturbing activities, disturbed areas associated with this project will be
covered with road base and gravel. There are no areas that are anticipated to be seeded. The final
site map (Tab 2) will be updated to indicate which BMPs will be used at specific locations during final
stabilization. The site map is a dynamic document changing with field conditions. Proposed BMPs
are initially placed on the site maps and then these maps are updated in the field to reflect changes
as the project moves forward and final stabilization measures occur. The maps prepared for this
SWMP include an initial/interim map showing initial BMPs and those BMPs used during construction
and a final map showing BMPs to be used to achieve final stabilization.
Final Stabilization Methods (§I.C.4.b)
Final stabilization includes those measures taken to control pollutants in stormwater after soil
disturbing activities are complete. Practices implemented to achieve final stabilization include:
• Hardscaping
• Applying 4 inches of gravel on top of 6 -inches of road base within access roads and post -
construction work areas within the substation;
• Rock on the fill slopes associated with the realigned access road; and
• Removal of temporary BMPs once work is completed and final stabilization achieved.
Final Stabilization Achievement ($I.C.4.c)
Final stabilization is achieved when all ground surface disturbing activities at the site have been
completed and uniform vegetative cover has been established with an individual plant density of at
least 70 percent of pre -disturbance vegetative cover, or equivalent permanent, physical erosion
reduction methods have been employed. When final stabilization is achieved, temporary erosion and
sediment control measures will be removed.
Long Term Stormwater Management 14I.C.4.d).
Long-term stormwater management for this project will be restoring the site to pre -condition
conditions. The actual footprint of the substation or any of its yard is not anticipated to change due to
this project.
Tab 12
Pre -Construction Photos
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MAP INFORMATION
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Soil Map—Rifle Area, Colorado. Parts of Garfield and Mesa Counties
Map Unit Legend
Rifle Area, Colorado, Parts of Garfield and Mesa Counties (CO683)
Map Unit Symbol
Map Unit Name 1 Acres in AO1
Percent of AO1
4
Arvada loam, 6 to 20 percent
slopes
Totals for Area of Interest
3.7
3.7
100.0%
100.0%
USDA Natural Resources Web Soil Survey
Conservation Service National Cooperative Soil Survey
11/25/2015
Page 3of3
RUSLE2 Related Attributes ---Rifle Area, Colorado, Parts of Garfield and Mesa Counties
RUSLE2 Related Attributes
This report summarizes those soil attributes used by the Revised Universal Soil
Loss Equation Version 2 (RUSLE2) for the map units in the selected area. The
report includes the map unit symbol, the component name, and the percent of the
component in the map unit. Soil property data for each map unit component include
the hydrologic soil group, erosion factors Kf for the surface horizon, erosion factor
T, and the representative percentage of sand, silt, and clay in the mineral surface
horizon. Missing surface data may indicate the presence of an organic surface
layer. .
Report—RUSLE2 Related Attributes
Soil properties and interpretations for erosion runoff calculations. The surface
mineral horizon properties are displayed. Organic surface horizons are not
displayed.
RUSLE2 Related Attributes—Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Map symbol and soil name
Pct. of
map unit
Slope
length
(ft)
Hydrologic group
Kf
T factor
Representative value
•1. Sand
% Silt
% Clay
4—Arvada loam, 6 to 20 percent
slopes
Arvada
85
—
C
.32
2
41.6
37.4
21.0
Data Source Information
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Survey Area Data: Version 9, Sep 22, 2015
USDA Natural Resources Web Soil Survey
21011 Conservation Service National Cooperative Soil Survey
11/25/2015
Page 1 of 1