HomeMy WebLinkAbout1.01 Supplemental Application InfoPO Box 248 Carbondale, CO 81623 (970) 947-9568
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update -December 7,2017
Community Development Department
Garfield County
108 8th Street, Suite 401
Glenwood Springs, CO 81601
Re:Grading Permit Application for Fish Bypass Channel of Elk Creek Project
To whom it may concern,
Introduction
The purpose of this memorandum is to request a Floodplain Development Applications approval from the
Garfield County for the Fish Bypass Channel of Elk Creek Project (Project). The Project is sponsored by
Trout Unlimited in coordination with Colorado Parks and Wildlife (CPW), the Ware and Hinds Ditch
Company and local land owners, Eric Williams and Ross Talbott.
Project Description and Proposed Construction Schedule
The proposed Project includes the construction of a fish passage channel on the north bank of Elk Creek
to provide fish passage across the Ware and Hinds diversion dam for rainbow trout, brown trout and other
fish species. The fish passage channel will be constructed primarily of boulder and cobble. Upper sections
of the channel will be treated with seeding, planting and erosion control matting.The proposed channel is
3-4 feet wide. The depth of the cut varies from 2 to 5 feet. The boulder lined channel itself will be 18-
inches deep. Above this low flow channel, the excavation will catch with a 3:1 to 5:1 side slope that is
either rocked or matted and seeded.A portion of the existing dam structure will be cut and brackets for
installing stop logs will be added. Two small, low relief rock vanes will be placed into Elk Creek at the
downstream and upstream entrances to the channel. These will create a local scour zone at the entrances
to minimize sediment accumulation that could potentially block the entrance to the channel, particularly
on the upstream side.
The channel will function by routing a portion of the flow from Elk Creek through the fish passage
channel. The channel has been designed to utilize a series of vertical slots and roughened ramps created
by the boulder and cobbles to reduce velocities to a level that will provide passage for aquatic species
around the Ware and Hinds diversion dam.
Total permanent change to the landscape has an area of 0.02 acres. Disturbance area of the project during
construction is 0.60 acres, including all staging, access roads and stockpile areas.
The proposed schedule for construction of the Elk Creek Fish Passage Channel Project is as follows:
-December 4, 2017 –Advertise project for bid
-December 20, 2017 –Award Bid to Contractor
-January 3, 2018 –Mobilization and Installation of Erosion and Sediment Control BMP’s
-January 8, 2018 –Construction of Fish Passage Channel Begins
PO Box 248 Carbondale, CO 81623 (970) 947-9568
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-January 24, 2017 –Majority of Fish Passage Channel Construction Complete
-February 2, 2018 –Final Walk Through Punchlist, removal of Erosion and Sediment Control
BMP’s and Demobilization Complete
Section 3-301 Compliance (only applicable sub-sections are listed)
A.Use Restrictions in Floodplain Overlay
Of the available categories, the project fits best in “Bank Restoration and Stabilization”. This type
of work is permitted in Floodways and 100-year floodplains as long as there is compliance with
all other applicable standards of the Code.
B.General Standards
The channel will be constructed of boulder and large cobble. The stop log structure will be
constructed of concrete and dimensional lumber.Materials were selected and sized and will be
placed to prevent floatation, collapse or lateral movement. These materials will be resistant to
flood damage.
C.Floodway
The project site is in a section of Elk Creek that is not a detailed study area for FEMA, meaning
that a hydraulic model, such as HEC-RAS was not used for delineating the 100-year floodplain
boundary. As such, the 100-year Floodplain is categorized as Zone A and a Base Flood Elevation
and Floodway boundary has not been established.
A “No-rise” Certification Letter is included in this submittal as part of a separate memo. (Fish
Channel of Elk Creek, Floodplain Compliance, Dated October 2, 2017)
In summary: with no established Base Elevation and a net cut of material on the project,
RiverRestoration asserts that a detailed floodplain analysis is not necessary for this project. The
proposed channel has a net cut of 120 cubic yards compared to existing conditions and the
proposed opening in the existing concrete structure has an cross sectional area of 18 square feet.
These project related reductions in fill and cross section will provide additional conveyance
through the project reach. Admittedly this additional conveyance will be minimal as compared to
the total flow in Elk Creek during the 100-year flood event.In conclusion, the proposed project
will not create a rise in water surface elevations associated with the 100-year floodplain of Elk
Creek or change the extents of the 100-year floodplain boundary.
G.Alteration of a Water Course
Hydrology and Hydraulics:
During certain times of year, the project will route a portion of stream flow around the north side
Ware and Hinds diversion dam in a proposed fish passage channel.Flow returns to Elk Creek
immediately downstream of the diversion dam. During the time when the Ware and Hinds
PO Box 248 Carbondale, CO 81623 (970) 947-9568
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diversion company is calling water (typically late summer/early fall), the proposed fish bypass
channel will be blocked with stops logs.
The project was designed hydraulically,using SRH-2D, a 2-dimensional hydraulic model
developed by the US Bureau of Reclamation. The design effort targeted specific velocities (<6
ft/s), depths (>1.0 ft)and vertical drop (0.0 ft) parameters as specified by Colorado Parks and
Wildlife (CPW). These parameters have been met for the expected range of flows, providing fish
passage around the diversion dam for rainbow trout and brown trout and potentially other fish
species.The hydraulic modeling results were also used to calculate scour potential, size boulders
and determine alluvial backfill gradation.A summary table of model output and graphics of the
2D modeling at various flows are included as attachments.
See the attached stamped plans for more details on fish bypass channel and stop log structure.
Regulatory compliance:
From a federal and state regulatory standpoint, the project was verified by the US Army Corps of
Engineers (USACE) to be constructed under Regional General Permit (RGP) 12 –Aquatic
Habitat Improvement for Stream Channels in Colorado. The verification letter is dated October
25, 2016 and is valid until October 25, 2018. The project was assigned identification number
SPK-2016-00684. A copy of the verification letter from the USACE is included as an attachment.
The contractor will be responsible for acquiring the required NPDES permits for construction
through the State of Colorado. The contractor may use the included Erosion Control Plan shown
in the plan set and discussed in the technical specifications as a guide. The application will be due
10 days prior to start of construction activities. Due to its small size, the project will likely be able
to be permitted under CDPS General Permit, Stormwater Discharges Associated with
Construction Activity, COR-030000.
A Grading Permit Application was submitted to the Town of New Castle on September 18, 2017
and approval was received October 20, 2017. A copy of the Grading Permit Application is
available upon request.
Floodplain and Floodway:
As discussed in “C”above,the project site is in a section of Elk Creek that is not a detailed study
area for FEMA, meaning that a hydraulic model, such as HEC-RAS was not used for delineating
the 100-year floodplain boundary. As such, the 100-year Floodplain is categorized as Zone A and
a Base Flood Elevation and Floodway boundary has not been established.
The “No-rise” Certification Letter is included in this submittal as part of a separate memo.(Fish
Channel of Elk Creek, Floodplain Compliance, Dated October 2, 2017)
PO Box 248 Carbondale, CO 81623 (970) 947-9568
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Maintenance:
Colorado Parks and Wildlife will be responsible for maintenance of the fish passage channel,
removing accumulated sediment and debris as required, likely on an annual or semi-annual basis.
Trout Unlimited has also developed an informal agreement with the Ware and Hinds ditch
company to remove accumulated sediment and debris in Elk Creek at the upstream mouth of the
proposed fish passage channel during their regular maintenance of the Ware and Hinds ditch
headgate.
Section 4-109 Compliance (only applicable sub-sections listed)
The project is in compliance with Section 3-301, Floodplain Overlay Regulations. A “No-rise”
Certification Letter is included in this submittal as part of a separate memo. (Fish Channel of Elk
Creek, Floodplain Compliance, Dated October 2, 2017)See additional explanation in the
response to 3-301.C above.
The project, a small, fish bypass channel in the floodplain of Elk Creek will provide upstream and
downstream passage of various aquatic species around the Ware and Hinds Diversion Dam. By
its nature, it is required for the project to be at its proposed location. The project will have no
impacts on velocities, sediment transport or wave action in Elk Creek during high flow events.
The project will not impact adjacent property owners.
Section 4-203 Compliance (only applicable sub-sections listed)
A.Professional Qualifications
The project was designed under direction and guidance of a Professional Engineer in the state of
Colorado, license #38797.
B.General Application Materials
See attached documents for the general application materials submitted as part of this Floodplain
Development Application.
C.Vicinity Map
See attached vicinity map showing the location of the project on Elk Creek just upstream and
west of New Castle, CO.
D.Site Plan
See attached plan set (Fish Bypass Channel of Elk Creek, Dated December 1, 2017)for the Site
Plan and the required elements.
PO Box 248 Carbondale, CO 81623 (970) 947-9568
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E.Grading and Drainage Plan
See attached plan set (Fish Bypass Channel of Elk Creek, Dated December 1, 2017)for the
Grading and Drainage Plan and the required elements.Project specifications are available upon
request.
Construction Schedule:
The proposed construction is included in the project description found on the first page of this
document.
Erosion and Sediment Control:
The majority of the work associated with the project, including cutting the existing dam, grading
of the channel, placement of boulders, installation of matting and revegetation will be performed
outside of Ordinary High Water and will not come in to contact with flowing waters of Elk Creek
during the expected construction window of January-February. Erosion and Sediment Control
(ESC) BMPs will be implemented to minimize impacts to Elk Creek and its riparian area. These
BMPs include access ramps, silt fence, oil booms, turbidity curtains, and dewatering filters.The
construction of the downstream outlet and upstream inlet will require work inside OHW and a
high likelihood of contact the flowing waters of Elk Creek. These two structures are small in
scale and are anticipated to only take a few days each to construct. Erosion and Sediment Control
(ESC)BMPs will also be implemented to minimize impact to Elk Creek during this period,
including oil booms, turbidity curtains and dewatering filters. See Sheets EC01-EC05 for more
details on the ESC plan
Estimated Cost:
The total estimate construction cost for the project, including soft costs and contingency is
$110,000. See the attached Final Design Cost Opinion, Dated November 10, 2017 for more
information.
Stormwater Management Plan:
The site is less than 1 acre, so a Stormwater Construction Permit issued by CDPHE is not
required. The contractor will be required to submit for and receive a construction dewatering
permit through CDPHE.
Reclamation, Revegetation and Soil Plan:
See attached plan set, sheet R01 for the revegetation and restoration plan for the site. In summary,
the 3:1 to 5:1 banks of the proposed fish passage channel will be covered with an erosion control
blanket and seeded with a wetland or riparian seed mix. Willow root balls and stakes within the
excavation area will be harvested and replanted on the proposed channel banks and disturbed
areas on the floodplain bench.
Site is less than 1 acre and does not require a Weed Management Plan.
PO Box 248 Carbondale, CO 81623 (970) 947-9568
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Seed mixes to be used on the project:
Riparian buffer seed mix (Upstream of Structure)
Common name Scientific name
Growth
form
Revegetation
technique % in mix *
Western wheatgrass Pascopyrum smithii grass
seed (drill or
broadcast)25
Blue grama Bouteloua gracilis grass
seed (drill or
broadcast)25
Slender wheatgrass Elymus trachyculus grass
seed (drill or
broadcast)10
Alkali sacaton Sporobolus airoides grass
seed (drill or
broadcast)11
Indian ricegrass
Achatherum
hymenoides grass
seed (drill or
broadcast)10
Inland saltgrass Distichlis spicata grass
seed (drill or
broadcast)15
Palmer penstemon Penstemon palmeri forb
seed (drill or
broadcast)2
Solidago canadensis Canada goldenrod forb
seed (drill or
broadcast)2
Wetland area seed mix (Downstream of Structure)
Western wheatgrass Pascopyrum smithii grass broadcast seeding 20
Inland saltgrass Distichlis spicata grass broadcast seeding 30
Alkali grass Puccinellia airoides grass-like broadcast seeding 20
Alkali muhley
Mulenberghia
aspertifolia grass-like broadcast seeding 20
Arctic rush Juncus arcticus grass-like broadcast seeding 2
Common spikerush Eleocharis palustris grass-like broadcast seeding 2
Alkali bulrush Scirpus maritimus grass-like broadcast seeding 2
Marsh milkweed Asclepsia incarnata forb broadcast seeding 2
Nutall's sunflower Helianthus nuttallii forb broadcast seeding 2
* Note -species percentages are a general guidance and can be changed with Engineer's approval. All
seeds must be raked into placed topsoils and covered with soil (or drill-seeded), then soils tamped down
prior to installation of the erosion control blankets.Additional seed to be broadcast seeded on top of install
matting.
Hydraulic Calculations:
See response to 3-301.G for a discussion on the hydraulic calculations.
PO Box 248 Carbondale, CO 81623 (970) 947-9568
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Spill Prevention Control and Countermeasures:
From the project specifications:
a.A Spill Cleanup Plan is wholly the responsibility of the CONTRACTOR and shall be
posted and available at all times on site for all work areas prior to any construction
activities and shall include coordination with local emergency response agencies.
CONTRACTOR shall submit Spill Cleanup Plan to ENGINEER for review 5 days prior
to the start of construction.
b.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) shall be reported to the Colorado Department of
Public Health and Environment immediately (25-8-601 CRS) and form
http://www.cdphe.state.co.us/hm/spillselfreportform.pdf and/or Toll-Free 24-hour
Environmental Emergency Spill Reporting Line 1-877-518-5608 may be used. Written
notification to the Department shall follow within five (5) days (5 CCR 1002-61, Section
61.8(5)(d)). Releases of petroleum products and certain hazardous substances listed
under the Federal Clean Water Act (40 CFR Part 116) must be reported to the National
Response Center as well as to Colorado Department of Public Health and Environment as
required under the Clean Water Act and the Oil Pollution Act. Furthermore, contact must
be made immediately, reporting any spill incident, with CPW, the OWNER and
ENGINEER.
c.Any incident spills that do not threaten water resources shall be reported to: Colorado
Emergency Planning Committee (CEPC)(members include Colorado Department of
Health and Environment -Hazardous Waste Division, Colorado Department of Public
Safety -Division of Homeland Security and Emergency Management, and Colorado
Department of Public Safety -Colorado State Patrol), at Toll-Free 24-hour Colorado
Environmental Release and Incident Reporting Line 1-877-518-5608,
https://www.colorado.gov/pacific/cdphe/wq-environmental-spills. Furthermore, contact
must be made immediately, reporting any spill incident, with the Town New Castle
Public Works Department, the OWNER and ENGINEER. The CONTRACTOR shall
submit within 14 calendar days of knowledge of the release a written description of: the
release (including the type and estimate of the amount of material released), the date that
such release occurred, the circumstances leading to the release, the measures taken and/or
planned to be taken to cleanup the release, and steps to be taken to minimize the chance
of future occurrences to the Executive Secretary
O.Floodplain Analysis
PO Box 248 Carbondale, CO 81623 (970) 947-9568
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The attached floodplain analysis (Fish Channel of Elk Creek, Floodplain Compliance, Dated
October 2, 2017) meets the provisions of Section 4-203 (O). See write up on individual sections
below.
1.See attached plan set for compliance with this section. The plan set includes Zone A
floodplain boundary (no BFE or floodway established on this section of Elk Creek), channel
of water course, existing and proposed 1-ft contours, existing and proposed structures and
land alterations, boundary and location of existing water supply ditches.
4.The proposed Project includes the construction of a fish passage channel on the north bank of
Elk Creek to provide fish passage across the Ware and Hinds diversion dam for rainbow
trout, brown trout and other fish species. The fish passage channel will be constructed
primarily of boulder and cobble. Upper sections of the channel will be treated with seeding,
planting and erosion control matting. The proposed channel is 3-4 feet wide. The depth of the
cut varies from 2 to 5 feet. The boulder lined channel itself will be 18-inches deep. Above
this low flow channel, the excavation will catch with a 3:1 side slope that is either rocked or
matted. A portion of the existing dam structure will be cut and brackets for installing stop
logs will be added. Two small, low relief rock vanes will be placed into Elk Creek at the
downstream and upstream entrances to the channel. These will create a local scour zone at the
entrances to minimize sediment accumulation that could potentially block the entrance to the
channel, particularly on the upstream side.
The channel will function by routing a portion of the flow from Elk Creek through the fish
passage channel. The channel has been designed to utilize a series of vertical slots and
roughened ramps created by the boulder and cobbles to reduce velocities to a level that will
provide passage for aquatic species around the Ware and Hinds diversion dam.
5.As discussed above,the project site is in a section of Elk Creek that is not a detailed study
area for FEMA, meaning that a hydraulic model, such as HEC-RAS was not used for
delineating the 100-year floodplain boundary. As such, the 100-year Floodplain is
categorized as Zone A and a Base Flood Elevation and Floodway boundary has not been
established.
The “No-rise” Certification Letter is included in this submittal as part of a separate memo.
(Fish Channel of Elk Creek, Floodplain Compliance, Dated October 2, 2017)
It concludes, the proposed project will not create a rise in water surface elevations
associated with the 100-year floodplain of Elk Creek or change the extents of the 100-
year floodplain boundary
PO Box 248 Carbondale, CO 81623 (970) 947-9568
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Please contact me at the email address or phone number below with any questions or concerns.
Sincerely,
Quinn L.Donnelly,P.E.
Project Manager
quinn.donnelly@riverrestoration.org
(970) 947-9568