Item 3B - WET2022-00007M E M O R A N D U M
TO: Planning Board
FROM: Edward Stafford, P.E., PTOE, Senior Civil Engineering Manager
DATE: August 8, 2023
CALL UP ITEM: Standard Wetland Permit (WET2022-00007)
Boulder County Culvert Replacement at Baseline Road
Key Dates
Wetland permit approved by staff: August 8, 2023
The decision may be called up by Planning Board on or before: August 22, 2023
There is one Planning Board meeting within the 14 day call up period on: August 22, 2023
Project Description
City Wetland Permit Applications are required for projects located outside of city limits when
the proposed project is on city owned or managed land. This project is located outside of city
limits at Dry Creek No. 3 at Baseline Road (See Attachment A) on property owned by the City
of Boulder and managed by Open Space & Mountain Parks (OSMP).
Boulder County is proposing to replace one existing concrete culvert with two 18-foot by 10.5-
foot concrete box culverts under Baseline Road. The additional box culvert is for creek overflow
and a potential future trail extension. The project also includes installation of guardrail, erosion
control measures, overlaying of asphalt on the roadway, asphalt patching on the roadway, and
minimal creek re-alignment.
After the culvert is replaced, the creek area will be reseeded with wetland seed mix and
plantings. No trees will be removed and there will be no impact to surrounding trails. The site
will be monitored for five years or until wetland permit application success criteria is met.
Wetland Review Criteria for Standard Wetland Permits
•Hydrology: historical water flows will remain in place and stream hydrology will not be
impacted.
•Minimization: The culvert replacement is at the same location as the existing culvert
which will minimize disturbance outside of the existing culvert location. The primary
impact of this project is temporary disturbance to emergent wetlands. A stabilized staging
area with concrete washout structure will be placed on the south side of baseline road at
the access point for vehicles to enter the creek. This staging area is outside of wetland
and wetland buffer zones.
Item 3B - WET2022-00007
•Restoration of Temporary Impacts: Any soil disturbance will be seeded with native seed
mix approved by OSMP and will occur onsite.
•Best Management Practices: Construction will take place during low water runoff to
ensure minimal disturbance. Silt curtains, silt fence, wattles and possibly coffer dams will
be installed during construction to prevent erosion and excess sediment from entering the
creek.
•Protection of Species: The area is unlikely to impact any threatened or endangered
species and has received all required clearances and approvals from the Army Corps of
Engineers.
•Mitigation Plan: While the existing wetlands are considered to be high functioning, this
stream restoration project will improve and enhance the water quality and stream bank
stabilization resulting in greater long term wetland functionality for the corridor. In these
enhancement scenarios, wetlands are mitigated at a 1:1 ratio.
The proposed project will have the following impacts to city regulated wetlands:
Permanent
(sq. ft.)
Temporary
(sq. ft.)
Water Body 1,320 775
Inner Buffer 480 9,110
Outer Buffer 15 5,500
Associated Floodplain Development Permits
The project will be required to submit a Stream Restoration permit and Floodplain Development
Permit to Boulder County.
Other Information
OSMP also reviewed and approved this wetland permit application.
The report refers to a set of engineering plans. Only relevant pages have been included to
consolidate for Planning Board’s consumption. The full plan set is available upon request.
Questions about the project should be directed to:
Edward Stafford, P.E., PTOE
Senior Civil Engineering Manager
303-441-4276
StaffordE@bouldercolorado.gov
Item 3B - WET2022-00007
Attachments:
A. Vicinity Map
B. Wetland Permit Application
C. Wetland Permit Report, Engineering Drawings and Army Corps Approvals
Item 3B - WET2022-00007
Item 3B - WET2022-00007
Planning & Development Services | 1739 Broadway, 3rd Floor
P.O. Box 791 Boulder, CO 80306 303-441-1880 boulderplandevelop.net
Page 1 of 4 Updated June 2020
WET2020-
Wetland Permit Application
•Wetland permits are required for development that impacts regulatory wetland and buffer zone areas and is
required by Section 9-3-9 (see Table 3-1 for required permit type and exemptions) of the Boulder Revised Code.
•Incomplete applications will not be accepted. Please fill out every section of this form.
REQUIRED MATERIALS FOR ALL PERMITS
Site Plan (please show the wetland and buffer zone boundaries)
At least two photographs of current conditions
Construction drawings (as applicable)
TO SUBMIT YOUR WETLAND PERMIT APPLICATION
Save your application and supplemental files as PDFs
Name your materials according to the File Naming Convention in the Electronic Submittal Guide
Submit application and files to PDSskipatrip@bouldercolorado.gov
CONTACT INFORMATION
Applicant Contact Information
Name Phone # Email Address
Address City State Zip
Property Owner Contact Information
Same as Applicant
Name Phone # Email Address
Address City State Zip
PERMIT
Date:
WET2022-00007
Item 3B - WET2022-00007
Planning & Development Services | 1739 Broadway, 3rd Floor
P.O. Box 791 Boulder, CO 80306 303-441-1880 boulderplandevelop.net
Page 2 of 4 Updated June 2020
PROJECT INFORMATION
Permit Type (please check one) Standard
Boundary Determination
Conditional
Functional Evaluation
Project Address:
Project Description: please include the who, what, where, when and why in your project description (please also
describe if this project is part of a larger project)
PROJECT IMPACTS
Impact Area
(permanent & temporary)
Total Impacted Area
(square feet)
Required Restoration Ratio
(area restored to area disturbed)
Wetland 2:1
Inner & Outer Buffer Zone 1:1
BEST MANAGEMENT PRACTICES
Describe how you will keep sediment or erosion from entering the creek.
HYDROLOGY
Check all that apply:
Current Water Source Groundwater Stream water Rainwater Other:
Future Water Source Groundwater Stream water Rainwater Other:
Will your project negatively impact site hydrology? Yes No
If yes, please describe:
Stream water
Item 3B - WET2022-00007
Planning & Development Services | 1739 Broadway, 3rd Floor
P.O. Box 791 Boulder, CO 80306 303-441-1880 boulderplandevelop.net
Page 3 of 4
Updated June 2020
MINIMIZATION
Describe the steps taken to ensure that your project is causing the least amount of wetland disturbance.
RESTORATION OF TEMPORARY IMPACTS
I will be utilizing native wetland seed mix for restoration. Yes No
If no, please explain:
Will you be restoring at the project location? Yes No
If no, please describe where your restoration will occur:
OTHER ITEMS TO CONSIDER
Does your project include any of the following? Check all that apply:
Bank Stabilization Native plants/landscaping are preferred over rip rap or hardened structures (as feasible).
Vegetation Removal For noxious weed infestation or native habitat restoration only (applies to inner buffer).
New Steps/Pathway Only allowed in buffer zones, one per property, and 4-feet wide maximum.
Sediment Removal Shall not alter flood capacity. Vegetated channel bottoms shall be restored.
Fill Identify the source of any fill, and the location where any fill will be placed
If you checked any of the above, please describe:
None of these apply to my project
Item 3B - WET2022-00007
Planning & Development Services | 1739 Broadway, 3rd Floor
P.O. Box 791 Boulder, CO 80306 303-441-1880 boulderplandevelop.net
Page 4 of 4
Updated June 2020
For Standard Review Applications Only
PROTECTION OF SPECIES
Check one and attach to application:
Army Corps of Engineers Nationwide Permit
Army Corps of Engineers 404 Permit AND US Fish and Wildlife Threatened & Endangered Species Permit
MITIGATION PLAN
Please provide a mitigation plan that addresses the following items in the order listed below.
1. Statement that mitigation plan was prepared by qualified wetland biologist
2. Existing site evaluation
a. Type and value of existing wetlands
b. Total area impacted (use table above)
c. Total area to be mitigated (use ratios in table above)
d. Construction start/end date
3. Mitigation Site
a. Location
b. Who owns the mitigation site (do you have their approval?)
c. Description of mitigation (i.e. is the site suitable for wetlands?)
d. Hydrology description
i. where will the water come from to establish the wetland?
ii. Who owns the water? Do you have their consent?
e. Mitigation start/end date
f. Probability of success of mitigation measures
4. Mitigation Site Maintenance
a. Description of maintenance activities: weed control, litter removal, irrigation, water control structures,
vegetation maintenance (replanting), culvert clearing
b. When will maintenance start?
c. Who will perform maintenance?
d. How often will maintenance be performed?
e. When will maintenance end?
5. Mitigation Site Monitoring
a. Monitoring criteria: how will you know the site is successful? 80% revegetated, no noxious weeds
b. When will monitoring start?
c. Who will perform the monitoring?
d. When will monitoring end?
Item 3B - WET2022-00007
CORVUSenvironmental.com
Environmental Consulting LLC
CORVUS
City of Boulder Wetland Mitigation Plan for
Dry Creek No. 3 at Baseline Road Culvert
Replacement
Boulder County
July 10, 2023
Presented to:
City of Boulder
On behalf of:
Boulder County Public Works
Through:
OTAK
Prepared by:
Item 3B - WET2022-00007
CORVUS Environmental Consulting LLC Page ii
Project Information Summary
Name Dry Creek No. 3 at Baseline Road Culvert Replacement
Permittee Boulder County Public Works
Permittee Contact
Dave Webster, PE
Boulder County Public Works, Engineering Division
2525 13th St, Suite 203
Boulder, CO 80304
720-564-2660
dwebster@bouldercounty.org
Consulting Agent
Tim DeMasters
CORVUS Environmental Consulting, LLC
6419 S. Marion Pl.
Centennial, CO 80121
303-872-7084
tdemasters@corvusenv.com
Project Purpose and Need
The project purpose is to replace an existing, but failing, structure
to allow for increased road safety, and adequate capacity during
high-flows.
Project Location
Baseline Road at Dry Creek No. 3, near the Dry Creek Trail Head.
Approximate center (Decimal Degrees):
• 40.000113, -105.191023
Summary of Proposed Activities The proposed project would replace the existing failing culvert
with a slightly larger one designed for a larger flood event.
Item 3B - WET2022-00007
Dry Creek No. 3 at Baseline Road Culvert Replacement COB Mitigation Plan
CORVUS Environmental Consulting LLC Page 1
Statement that this mitigation plan was prepared by qualified wetland
biologist
This mitigation plan has been prepared by a qualified wetland biologist at CORVUS Environmental
Consulting, LLC. Tim DeMasters has over 17 years of experience delineating, permitting, and restoring
wetlands.
Existing site evaluation
Uplands
Uplands were observed starting at the top of bank, at a well-defined break in topography and change in
vegetation. Common species included Canada thistle (Cirsium arvense), smooth brome (Bromus inermis)
common teasel and Kentucky blue grass (Poa pratensis). During the October 2021 site visit, areas
including uplands on the south side of Baseline Road had been mowed to control common teasel.
Transition zones between the uplands and wetlands were dominated by tall fescue (Shedonorus
arundinaceus) Baltic rush, and common three-square.
Open Waters
Dry Creek Number 3 is the only open water present within the study area and was observed to be
approximately 6-8 feet wide by 1-3 feet deep at the OHWM. In this case (per City standards), the
waterbody has been mapped as “regulatory wetlands”, with two 25-foot regulatory buffers added (inner
and outer, respectively).
Type and value of existing wetlands
Per the City definitions, the existing “regulatory wetlands” are the open waters of Dry Creek Number 3,
which is a perennial stream. To be biologically accurate, we’ve described real/actual wetlands onsite.
CORVUS mapped continuous fringe Palustrine Emergent (PEM) wetlands along Dry Creek No. 3 within
the Study Area. Common species included Baltic rush (Juncus balticus), clustered field sedge (Carex
praegracilis), common three-square (Schoenoplectus pungens), Emory's sedge (Carex emoryi), common
teasel (Dipsacus fullonum), blue vervain (Verbena hastata), prairie cordgrass (Spartina pectinata), reed
canary grass (Phalaris arundinacea) and showy milkweed (Asclepias speciosa). Other species present to
a lesser extent in the overstory included coyote willow (Salix exigua), Russian olive (Elaeagnus
angustifolia), and crack willow (Salix fragilis).
The value of the existing wetlands is assumed to be considered “high functioning”.
Item 3B - WET2022-00007
Dry Creek No. 3 at Baseline Road Culvert Replacement COB Mitigation Plan
CORVUS Environmental Consulting LLC Page 2
Total area impacted (note column for OSMP):
Total area to be mitigated (note column for OSMP):
The total open water replacement account is slightly higher than existing condition, to construct a
functioning channel on an appropriate curve through the new culvert. Wetland mitigation will occur at
an increase in acreage, including coming very close to a 2:1 replacement on permanent wetlands. See
Table 1.
Item 3B - WET2022-00007
Dry Creek No. 3 at Baseline Road Culvert Replacement COB Mitigation Plan
CORVUS Environmental Consulting LLC Page 3
Table 1. Aquatic Resource Impacts and Mitigation on OSMP property
The inner and outer buffer impacts and mitigation will be 1:1. Buffer areas will be (mostly) temporarily
impacted, but the resulting buffers will be enhanced by shrub plantings, and noxious weed control.
Approximately 450 additional willow stakes will be installed within the buffer areas, to improve the
scrub-shrub canopy. Noxious weeds will be monitored for, and treated during the appropriate timing,
using approved methods. Russian olive trees and saplings will be removed. Notice will be provided to
OSMP prior to any herbicide application.
Construction start/end date
Boulder County Transportation plans to start construction during the summer of 2023 (approximately
August). The project is anticipated to take 120 days to arrive at substantial completion, which includes
the construction of the mitigation areas.
Mitigation Site
Location
The mitigation will occur on the same property impacted, both south and north of Baseline Road at Dry
Creek Number 3.
Who owns the mitigation site (do you have their approval?)
The mitigation site is owned by the City of Boulder. The applicant, Mr. Dave Webster (Boulder County
Public Works), has communicated with Ms. Bethany Collins at the City, who is aware of the project and
mitigation.
Description of mitigation (i.e. is the site suitable for wetlands?)
The mitigation will occur mostly in-situ for the open waters, the new channel will be slightly larger
(wider) than the existing channel. Wetland mitigation will occur as fringe wetlands, planted and seeded
along the new channel alignment, adjacent to the existing wetlands onsite, in areas suitable for re-
establishment. Minor grading, to achieve appropriate wetland hydrology, will occur where necessary to
expand the wetland areas to the maximum extent possible on the site. Approximately 750 willow
cuttings will be installed along the channel as part of the wetland mitigation.
To mitigate for impacts within the inner and outer buffers, an additional 450 willow stakes will be
planted within the inner buffer (at appropriate elevations based on the water table), to increase the
Impact Type Wetlands (ac)Open Waters (ac)Inner Buffer Outer Buffer
Temporary 0.029 0.008 0.130 0.002
Permanent 0.014 0.019 0.008 0.080
Total 0.043 0.027 0.138 0.082
Mitigation Type
Temporary Restoration 0.029 (included below)
Creation, replacement for
permanent impacts 0.023 0.036
Total 0.052 0.036
Item 3B - WET2022-00007
Dry Creek No. 3 at Baseline Road Culvert Replacement COB Mitigation Plan
CORVUS Environmental Consulting LLC Page 4
shrub cover, and noxious weed control will occur (1,200 willow stakes total, between wetland areas, and
inner buffer mitigation). All populations of Colorado List A and B Noxious Weeds found within the buffer
areas will be treated with the appropriate, and OSMP approved herbicide. This includes the removal of
Russian Olive trees or saplings.
Please see the attached Planting Plan for details on seedbed preparation, and OSMP-approved seed
mixes. CORVUS received these pre-approved mixes directly from City Staff, January 2023.
Hydrology description
Dry Creek Number 3 is a perennial stream, with sub-irrigated fringe wetlands on both banks. The
hydrology is relatively predictable and is likely to persist in future conditions.
Where will the water come from to establish the wetland?
Hydrologic inputs in the mitigated wetlands will be a mix of overbank inundation (high water) events, as
well as more consistent sub-surface saturation in the adjacent lateral edges of the stream.
Who owns the water? Do you have their consent?
Dry Creek Number 3 is owned by Seven (7) mutual ditch and reservoir companies. They are aware of
the project and the mitigation to occur onsite. The applicant and the 7 companies have an agreement
drafted, and no complications or objections are anticipated. The companies are:
• Andrews Farwell Ditch Co
• Base Line Land and Reservoir Co
• Cottonwood No. 2 Ditch Co.
• Dry Creek - Davidson Ditch Co.
• Enterprise Irrigation Canal Co.
• Lewis H. Davidson Ditch Co.
• Leyner Cottonwood Consolidated Ditch Co.
Mitigation start/end date
Mitigation construction will start towards the end of the construction project, per typical phasing
schedules, and will end by substantial completion of the project.
Probability of success of mitigation measures
The mitigation areas have a high probability of success based on the existing established wetlands,
careful design planning, and proximity to a reliable hydrology source (Dry Creek Number 3).
Mitigation Site Maintenance
The following maintenance activities will be conducted on the site:
• Noxious weed control
o Including Russian olive removal within buffer areas
Item 3B - WET2022-00007
Dry Creek No. 3 at Baseline Road Culvert Replacement COB Mitigation Plan
CORVUS Environmental Consulting LLC Page 5
• Litter removal
• Irrigation of trees and shrubs (if applicable)
• Vegetation maintenance (replanting), as necessary
• Overseeding, if required
• Culvert clearing
When will maintenance start?
The wetland maintenance will begin during the first full growing season after construction (assumed
2024).
Who will perform maintenance?
A proven and qualified landscape contractor, with a current Commercial Applicator Business license in
the State of Colorado, selected by the County during contracting or through an on-call list.
How often will maintenance be performed?
Maintenance activities will be scheduled twice during each growing season, during spring and summer,
or as needed. The spring site visit will coincide with the early flowering of any noxious weeds present,
and occur prior to seed dispersal.
When will maintenance end?
Maintenance activities will conclude once the site is meeting or exceeding all monitoring criteria listed
below.
Mitigation Site Monitoring
Monitoring criteria
Wetland mitigation monitoring will be conducted using a quantitative field assessment methodology,
such as vegetation classification using a 1- square meter plot randomly placed, or vegetative transects,
to arrive at absolute percent areal cover.
The following monitoring criteria are proposed for this project:
• At least 80% native vegetative cover
• Invasive species on the Colorado Noxious Weed Inventory list-A shall be 100% eradicated
• Invasive species on the Colorado Noxious Weed Inventory list-B shall encompass no more than
10% of the total cover of the restoration area
• Tree and shrub survival shall be 100%, and include volunteers
When will monitoring start?
The wetland mitigation site shall be monitored starting the first growing season after project
completion. In some instances, this may be the same year, if the project is completed in the late winter
or spring.
Item 3B - WET2022-00007
Dry Creek No. 3 at Baseline Road Culvert Replacement COB Mitigation Plan
CORVUS Environmental Consulting LLC Page 6
Who will perform the monitoring?
Monitoring will be conducted by a qualified wetland biologist, with at least 3 years of professional
wetland delineation and assessment experience.
When will monitoring end?
The wetland mitigation site shall be monitored annually for five years by a qualified wetland biologist,
starting the first growing season. Monitoring reports shall be submitted to the City of Boulder Planning
and Development Services prior to September 1st of each year (or later if agreed upon by the City.
Generally monitoring occurs in August or even early September, and a submittal date of October 1st
would be better for the applicant). If it is determined that the mitigation is not successful, then
corrective measures will be established and implemented to ensure a successful wetland mitigation
project, or offsite mitigation options will be discussed with the City.
Item 3B - WET2022-00007
Environmental Consulting LLC
CORVUS
Planting and Seeding Plan
Dry Creek No. 3 at Baseline Road Culvert
Replacement
April 6, 2023
Presented to:
OTAK
Prepared by:
Item 3B - WET2022-00007
DC#3 AT BASELINE ROAD PLANTING PLAN
GENERAL NOTES
• THE CONTRACTOR WILL SUPPLY ALL PLANTS IN QUANTITIES SUFFICIENT TO COMPLETE THE
WORK SHOWN ON THE PLAN. ALL PLANT MATERIAL SHOULD MEET THE SPECIFICATIONS OF THE
AMERICAN STANDARDS FOR NURSERY STOCK (LATEST EDITION) AS SET FORTH BY THE
AMERICAN ASSOCIATION OF NURSERYMEN.
• AN ECOLOGIST WILL INSPECT SEED CERTIFICATIONS PRIOR TO DELIVERY/PICK UP IN ORDER TO
CONDUCT A QUALITY CONTROL CHECK (QC).
• ALL POPULATIONS OF COLORADO LIST A AND B NOXIOUS WEEDS FOUND IN OR WITHIN 100
FEET OF THE PROJECT AREA WILL BE TREATED WITH THE APPROPRIATE HERBICIDE(S) PRIOR TO
AND THROUGHOUT THE DURATION OF CONSTRUCTION. ALWAYS FOLLOW ALL LABEL
RECOMMENDATIONS, PRECAUTIONS AND RESTRICTIONS WHEN USING ANY HERBICIDE. READ
AND COMPLY WITH ALL HERBICIDE LABELS, ORGANIC OR NONORGANIC, FOR APPLICATION
RATES, MIXING INSTRUCTIONS, PROTECTIVE EQUIPMENT, RE-ENTRY PERIOD, GRAZING OR
HARVEST RESTRICTIONS AND OTHER SAFETY INFORMATION. HERBICIDES SHOULD BE APPLIED
ONLY BY RESPONSIBLE, LICENSED APPLICATORS.
• THE CONTRACTOR WILL PROVIDE SUBMITTALS FOR CONTAINERIZED PLANT MATERIAL
(WETLAND PLUGS), EACH SEED MIX, MULCH, AND TACKIFIER. SUBMITTALS FOR LIVE PLANT
MATERIAL AND THE SEED MIXES WILL INCLUDE THE SCIENTIFIC NAMES OF EACH SPECIES,
INCLUDING VARIETY AND SUBSPECIES (AS APPLICABLE). ADDITIONALLY, THE SEED MIX
SUBMITTALS WILL INCLUDE THE LOT NUMBER, TEST DATE, SEED TYPE AND VARIETY, PURITY
AND GERMINATION PERCENTAGE, CROP SEED PERCENTAGE, INERT MATTER PERCENTAGE,
WEED SEED PERCENTAGE, WEEDS BY NAME AND NUMBER PER POUND.
• ALL BEST MANAGEMENT PRACTICES (BMPS) USED SHALL BE SELECTED, INSTALLED,
IMPLEMENTED, AND MAINTAINED ACCORDING TO APPROPRIATE ENGINEERING, HYDROLOGIC
AND POLLUTION CONTROL PRACTICES.
• THE USE OF CHEMICALS, SUCH AS SOIL STABILIZERS, DUST PALLIATIVES, HERBICIDES, GROWTH
INHIBITORS, FERTILIZERS, DEICING SALTS, ETC., SHALL BE IN ACCORDANCE WITH THE
MANUFACTURER’S RECOMMENDED APPLICATION RATES, FREQUENCY, AND INSTRUCTIONS.
THESE CHEMICALS SHALL NOT BE USED, STORED, OR STOCKPILED WITHIN 50 HORIZONTAL FEET
OF THE CREEK OR OTHER AQUATIC HABITATS.
• CONSTRUCTION EQUIPMENT, FUELS, LUBRICANTS, AND OTHER PETROLEUM DISTILLATES SHALL
NOT BE STORED OR STOCKPILED WITHIN 50 HORIZONTAL FEET OF THE CREEK OR OTHER
AQUATIC HABITATS. EQUIPMENT FUELING AND SERVICING SHALL OCCUR ONLY WITHIN
APPROVED DESIGNATED AREAS.
• THE CONTRACTOR WILL FOLLOW ALL IRRIGATION REQUIREMENTS AS DETAILED IN THE
GRADING, DRAINAGE, AND EROSION CONTROL (GESC) PLAN (IF APPLICABLE)
TOPSOIL STOCKPILING
• THE ECOLOGIST WILL OVERSEE AND REVIEW TOPSOIL STOCKPILING ACTIVITIES.
• TOPSOIL STOCKPILES FROM WETLANDS SHOULD BE SEPARATED FROM OTHER STOCKPILES AND
PLACED IN WINDROWS. THE PILES SHOULD BE UNCOMPACTED AND LOW IN HEIGHT WITH SOIL
MOUNDS NO HIGHER THAN 10 FEET TO PRESERVE SOIL MICROBES AND IDEALLY NO HIGHER
THAN 4 FEET IF SPACE ONSITE ALLOWS.
Item 3B - WET2022-00007
DC#3 AT BASELINE ROAD PLANTING PLAN
• STOCKPILE TOPSOIL (SEPARATELY FROM SUBGRADE) FROM ALL OTHER AREAS DISTURBED BY
THE PROJECT IN WINDROWS, PILES SHOULD BE UNCOMPACTED AND LOW IN HEIGHT WITH SOIL
MOUNDS NO HIGHER THAN 10 FEET TO PRESERVE SOIL MICROBES AND IDEALLY NO WIDER
THAN 4 FEET IF SPACE ONSITE ALLOWS.
• USE A PLACARD TO IDENTIFY STOCKPILES AS “WETLAND TOPSOIL”, “TOPSOIL”, OR “SUBGRADE”.
• ALL TOPSOIL STOCKPILED LONGER THAN 1 MONTH SHOULD BE SEEDED WITH ITALIAN RYE
(LOLIUM MULTIFOLORUM) AT A RATE OF 2 LBS/1,000 SQUARE FEET.
• ALL TOPSOIL STOCKPILES SHOULD BE TESTED FOR STANDARD NUTRIENTS AND A U.S.
DEPARTMENT OF AGRICULTURE (USDA) TEXTURE ANALYSIS SHOULD BE COMPLETED. RESULTS
FROM THE NUTRIENT TEST AND USDA ANALYSIS SHOULD BE PROVIDED TO THE ECOLOGIST FOR
REVIEW PRIOR TO FINAL PLACEMENT. SOIL AMENDMENTS MAY BE ADJUSTED BASED ON THESE
TEST RESULTS.
• PRIOR TO TOPSOIL PLACEMENT, THE TOP ONE FOOT OF THE STOCKPILE MATERIAL SHOULD BE
MIXED WITH THE REMAINDER OF THE STOCKPILE TO DISTRIBUTE LIVING ORGANISMS.
SEEDBED PREPARATION
• AN ECOLOGIST WILL OVERSEE AND INSPECT ALL SEEDBED PREPARATION ACTIVITIES.
• DO NOT WORK WHEN SOILS ARE FROZEN, SNOW COVERED, WET, OR HAVE REACHED
PLASTICITY LIMIT(MUDDY).
• BEFORE TOPSOIL IS PLACED, SUB-SOIL IN ALL WORK AREAS (OTHER THAN THE IMMEDIATE
CHANNEL BANKS) WILL BE DECOMPACTED AND LOOSENED TO A DEPTH OF 12 INCHES.
• ACCESS ROADS AND STAGING AREAS WILL BE DECOMPACTED AND LOOSENED TO A DEPTH OF
18 INCHES PRIOR TO TOPSOIL PLACEMENT.
• WHEN SPREADING TOPSOIL, ENSURE THAT THE LAYER IS NOT COMPACTED BY USING A SOIL
PENETROMETER – IN GENERAL, PENETROMETER READINGS LESS THAN 200 POUNDS PER
SQUARE INCH (PSI) IN THE TOP 6 INCHES ARE APPROPRIATE. CONTRACTOR SHOULD PLACE
TOPSOIL IN A MANNER THAT PRECLUDES HAVING TO CONTINUOUSLY DRIVE OVER NEWLY
PLACED TOPSOIL.
• ALL FINISHED GRADES WILL BE LEFT ROUGH AND NATURAL WITH SOIL CLODS NO GREATER
THAN 2 INCHES IN DIAMETER, NO SMOOTH SURFACES OR STRAIGHT EDGES. CLODS GREATER
THAN 2 INCHES SHOULD BE FURTHER BROKEN UP USING AN APPROPRIATE TILLING METHOD
(DISCING, HARROWING, ETC.)
SEEDING, MULCHING, AMENDMENT APPLICATION
• NO CONSTRUCTION EQUIPMENT WILL BE ALLOWED IN THE PROJECT AREA AFTER SEEDING.
• ALL SEED BAGS BROUGHT ONSITE WILL BE TAGGED AND LABELED. SEED BAG TAGS WILL HAVE
THE FOLLOWING INFORMATION: PROJECT NAME, TOTAL POUNDS, THE SCIENTIFIC NAMES, AND
SEEDING RATE FOR EACH SPECIES.
• THE CONTRACTOR WILL STAKE THE SEEDING LIMITS AND OBTAIN APPROVAL FROM THE
ECOLOGIST PRIOR TO SEEDING.
• SEEDING WILL ONLY BE PERFORMED BETWEEN OCTOBER 1 AND WHEN THE GROUND FREEZES,
OR FROM WHEN THE GROUND THAWS TO JUNE 1, UNLESS OTHERWISE APPROVED BY THE
ECOLOGIST.
Item 3B - WET2022-00007
DC#3 AT BASELINE ROAD PLANTING PLAN
• ZONE A IS THE TOP OF THE BASEFLOW ELEVATION (I.E., LOW-FLOW ELEVATION) TO
APPROXIMATELY 15 FEET PAST BANKFULL CHANNEL; ZONE B IS APPROXIMATELY 15 FEET PAST
THE TOP OF BANKFULL CHANNEL TO THE OUTSIDE EDGE OF OVERBANK ELEVATION; ZONE C IS
ANYTHING ABOVE THE OUTSIDE EDGE OF THE OVERBANK ELEVATION; AS SHOWN IN THE
PROJECT PLANS. EXACT PLANTING LOCATIONS WILL BE BASED ON FINAL GRADING.
• ALL AREAS IN ZONE A WILL BE SEEDED WITH THE WETLAND SEED MIX (TABLE 1). ZONE B WILL
BE SEEDED WITH THE RIPARIAN MIX (TABLE 2). ZONE C WILL BE SEEDED WITH THE UPLAND
SEED MIX (TABLE 3).
• SEEDING RATES SHOWN IN THE TABLES ARE FOR DRILL SEEDING. RATES SHOULD BE DOUBLED
FOR BROADCAST SEEDING.
• GRANULAR MYCORRHIZAE (SUCH AS ENDO MYCORRHIZAE) WILL BE MIXED IN WITH EACH SEED
MIX AND APPLIED AT 20 LBS. PER ACRE FOR BROADCAST SEEDING TO ALL AREAS (INCLUDING
WETLANDS). IF DRILL SEEDING, APPLY 2 LBS. PER ACRE.
• ALL BANK TREATMENTS WILL BE SEEDED WITH THE WETLAND AND TRANSITION (WITH FORBS)
SEED MIXES (TABLES 1 AND 2).
• ALL AREAS WITH EROSION CONTROL BLANKET WILL BE DECOMPACTED, RESULTING IN A LOOSE,
SOMEWHAT UNIFORM SEED BED, AND WILL BE PREPARED USING RAKES AND OTHER HAND
TOOLS. PRIOR TO BLANKET PLACEMENT, SEED SHOULD BE BROADCASTED PER THE
APPROPRIATE MIX BASED ON THE PLANTED ZONE AT THE SPECIFIED RATE ( TABLES 1, 2, OR 3).
• ADJACENT SEED MIXES WILL OVERLAP BY APPROXIMATELY 3 FEET.
• IF BROADCAST SEEDING, RAKE IN SEED AND MYCORRHIZAE WITH RAKE TINES ALONG THE
CONTOURS OF THE SEEDED AREAS.
• AFTER SEEDING, ALL AREAS THAT LACK EROSION CONTROL BLANKET WILL HAVE CRIMPED
STRAW/MULCH INSTALLED AT A RATE OF 2,500 LBS/ACRE WITH 150 LBS/ACRE OF ORGANIC
PSYLLIUM DERIVED TACKIFIER.
WETLAND PLUG INSTALLATION
• ALL WETLAND PLUGS MUST BE INSPECTED FOR HEALTH, SIZE, SPECIES, AND QUANTITY UPON
ARRIVAL ONSITE. NOTIFY THE ECOLOGIST AT LEAST 3 BUSINESS DAYS PRIOR TO DELIVERY.
ALTERNATIVELY, LOCAL NURSERY INSPECTION OF PLANTS MAY BE ARRANGED PRIOR TO
DELIVERY. PLEASE NOTIFY THE ECOLOGIST AT LEAST 3 BUSINESS DAYS PRIOR TO SCHEDULED
DELIVERY.
• ALL WETLAND PLUGS SHOULD BE WATERED PRIOR TO TRANSPORT AND COVERED DURING
TRANSPORT. PLUGS SHOULD BE WATERED ONCE THEY ARRIVE ONSITE AND STORED IN A
SHADED LOCATION (OR IN LEE GULCH IF WATER LEVELS ALLOW).
• WETLAND PLUG INSTALLATION WILL BE CONDUCTED IN PHASE 1 OF THE REVEGETATION
PROCESS (PRIOR TO INSTALLATION OF CONTAINERIZED SHRUB MATERIAL).
• WETLAND PLUG INSTALLATION WILL ONLY BE PERFORMED BETWEEN WHEN THE GROUND
THAWS TO JUNE 1, OR AFTER UNLESS APPROVED BY THE ECOLOGIST.
• WETLAND PLUGS WILL BE INSTALLED IN ALL AREAS IN ZONE A (BASEFLOW ELEVATION TO TOP
OF BANKFULL CHANNEL).
Item 3B - WET2022-00007
DC#3 AT BASELINE ROAD PLANTING PLAN
WILLOW STAKING
WILLOW CUTTINGS WILL BE HARVESTED FROM THE SURROUNDING SITE (OR WITHIN BOULDER
COUNTY) WHILE DORMANT, SOAKED, AND INSTALLED ON APPROXIMATE 3-4-FOOT SPACING, ON
CENTER. CUTTINGS SHOULD BE APPROXIMATELY 3-5 FEET IN LENGTH. IT IS ANTICIPATED THAT WILLOW
CUTTINGS WILL BE MOSTLY COYOTE WILLOW (SALIX EXIGUA), HOWEVER, OTHER NATIVE WILLOWS
FOUND ON-SITE WOULD BE APPROPRIATE AS WELL. CARE SHOULD BE TAKEN TO AVOID HARVESTING
AND INSTALLING CRACK WILLOW (SALIX FRAGILIS), WHICH IS NON-NATIVE AND CONSIDERED WEEDY IN
COLORADO.
• AREAS FOR HARVEST WILL BE APPROVED BY A QUALIFIED ECOLOGIST PRIOR TO CUTTING
• REMOVE NO MORE THAN 20% OF THE BRANCHES FROM ANY SINGLE WILLOW PLANT
• DON’T REMOVE MORE THAN 30% OF THE OVERALL CANOPY COVER FROM ANY WILLOW STAND
• HARVEST STEMS EVENLY THROUGH THE STAND (E.G., NOT FROM ONE SIDE OF THE PLANT
ONLY)
• ALL WILLOW AND COTTONWOOD CUTTINGS WILL BE HARVESTED WHEN DORMANT (AFTER
LEAF DROP IN THE FALL, AND BEFORE BUD-BREAK IN THE SPRING) FROM LIVE PLANTS 0.5 TO 1.0
INCH IN DIAMETER. THE STEM WILL BE CLIPPED OF ALL BRANCHES BEFORE CUTTING AND THEN
TRIMMED TO THE DESIRED LENGTH.
• THE LOWER (ROOTING) END OF THE STEM WILL BE CUT AT A 45-DEGREE ANGLE AND THE UPPER
END WILL BE CUT AT A FLAT 90-DEGREE ANGLE.
• THE CUTTINGS WILL BE PLACED INTO WATER WITHIN FIVE MINUTES OF CUTTING AND
SOAKED—COMPLETELY SUBMERGED IF POSSIBLE—FOR AT LEAST 72 HOURS, BUT NOT MORE
THAN 14 DAYS, PRIOR TO PLANTING. THE CUTTINGS WILL BE KEPT WET UNTIL INSTALLED IN THE
GROUND AND WILL NOT BE ALLOWED OUT OF WATER FOR MORE THAN 15 MINUTES DURING
PLANTING.
• ALL CUTTINGS WILL BE TRIMMED AFTER INSTALLATION TO A HEIGHT OF NO MORE THAN 16
INCHES ABOVE GROUND.
• WILLOWS WILL BE INSTALLED APPROXIMATELY 1-3 FEET ABOVE THE HEIGHT OF LOW-FLOW,
WITH DEPTHS ADJUSTED TO PENETRATE THE WATER TABLE
BASED ON THE ACREAGE OF THE RESTORATION AREA, APPROXIMATELY 750 CUTTINGS SHOULD BE
HARVESTED, SOAKED, AND INSTALLED DURING THE APPROPRIATE TIME. THIS NUMBER MAY BE
ADJUSTED AS NEEDED BY THE SITE OWNER OR A QUALIFIED ECOLOGIST BASED ON LEVEL OF IMPACTS
OR AMOUNT OF AVAILABLE COLLECTION STANDS.
Item 3B - WET2022-00007
DC#3 AT BASELINE ROAD PLANTING PLAN
TABLE 1 - UPLAND SEED MIX
Item 3B - WET2022-00007
DC#3 AT BASELINE ROAD PLANTING PLAN
TABLE 2 - RIPARIAN SEED MIX
TABLE 3 - WETLAND SEED MIX
Item 3B - WET2022-00007
DC#3 AT BASELINE ROAD PLANTING PLAN
WETLAND PLUGS
Common Name Scientific Name NWPL2 Indicator Size Spacing (O.C.)Quantity
Coyote Willow Salix exigua FACW 3-5'4'750
Zone A-B1
Item 3B - WET2022-00007
United States Department of the Interior
FISH AND WILDLIFE SERVICE
Mountain-Prairie Region
IN REPLY REFER TO: 134 Union Boulevard, Suite 670
FWS/R6/ES Lakewood, Colorado 80228-1807
ECOSphere: 2022-0036244
April 21, 2023
Cody Wheeler
Regulatory Project Manager
U.S. Army Corps of Engineers
9307 South Wadsworth Boulevard
Littleton, Colorado 80128
Subject: Baseline Road Culvert Replacement at Dry Creek No.3
Dear Cody Wheeler:
The U.S. Fish and Wildlife Service (Service) received your original request for informal
consultation on May 5, 2022, and a re-initiation request on March 23, 2023, regarding Baseline
Road Culvert Replacement at Dry Creek No.3 (project) located in Boulder County, Colorado.
Per your email, you determined that the project may affect, but is not likely to adversely affect,
the Preble’s meadow jumping mouse (Zapus husonius prebeli, Preble’s mouse), and Ute ladies’
tresses orchid (Spiranthes diluvialis, ULTO) listed as threatened under the Endangered Species
Act (ESA). These comments have been prepared under the authority of the ESA of 1973, as
amended (16 U.S.C. 1531 et seq.).
The proponent proposes to replace a culvert along Baseline Road at the Dry Creek No. 3, just
west of the Dry Creek Trailhead parking lot. The project consists of replacing the existing culvert
with a double 18’ by 10.5’ cast-in-place, concrete box culvert with headwalls and wingwalls.
One box culvert is designed to convey the main channel and the second box culvert can provide
overflow conveyance and a potential trail extension in the future. The project also includes
installation of guardrail, erosion control, traffic control, seeding, milling, and overlaying of hot
mix asphalt, full depth hot mix asphalt, asphalt patching, minimal creek realignment to allow
better flows to the proposed structure. Expected permanent impacts to riparian habitat total 500
square feet.
The vegetation in the study area is noted to be dense, and ULTO is generally found in more open
sites. At least one species typically associated with ULTO, as described in current USFWS
survey guidelines for ULTO (USFWS 1992), was present during the site visit (blue vervain,
Verbena hastata). The potential habitat is only located on the south side of the culvert, and the
impact area will be minimized to a narrow area surrounding the culvert and ditch. A field survey
conducted by Corvus in August 2021 revealed no observations of ULTO in any wetland or
upland areas associated with this project.
Item 3B - WET2022-00007
2022-0036244: USACE Baseline Road Culvert Replacement at Dry Creek No.3 2
The project area is located approximately 0.15-mile northeast of Preble’s mouse occupied
habitat. However, potentially suitable habitat for Preble’s mouse was lacking/not consistent
throughout the project area (and areas southwest of the project area) on the south side of Baseline
Rd. Trapping attempts have occurred on the south side of Baseline Rd, near the project area;
however, these trappings attempts were negative. Potential habitat may exist on the north side of
Baseline Rd.; however, the consistent flows through the culvert, as well as the road, are
considered movement barriers, making it difficult for Preble’s mouse to cross over/under
Baseline Rd to the north. Therefore, Preble’s mice are not likely to not occur in areas north of
Baseline Rd at this location. Additionally, the project is dominated by invasive teasel (Dispacus
fullonum), and low to no shrub cover exists on the southern side of the culvert to be replaced on
the south side.
Based on the information provided in a biological assessment provided by Corvus that details
poor and disconnected riparian habitat quality and an absence of ULTO, the Service concurs
with your determination that the proposed project may affect, but is not likely to adversely affect,
Preble’s mouse and ULTO. Due to the deteriorated habitat quality, a mitigation ratio of 1:1 is
deemed acceptable for this project, as native plantings will ultimately improve habitat quality.
If any additional species that are federally-listed, proposed for federal listing, or candidate for
federal listing are found in the project area or if new information becomes available that reveals
that the action may impact such species in a manner or to an extent that was not previously
considered, this office should be contacted to determine if further section 7 consultation will be
required. If the proposed project has not commenced within one year, please contact the
Colorado Field Office to request an extension.
We appreciate your efforts to ensure the conservation of threatened and endangered species. If
you have questions or comments related to this project, please contact Kate Lunz of this office at
kathleen_lunz@fws.gov.
Sincerely,
Liisa Niva
Eastern Colorado Supervisor
Colorado Ecological Services Field Office
Item 3B - WET2022-00007
DEPARTMENT OF THE ARMY
CORPS OF ENGINEERS, OMAHA DISTRICT
DENVER REGULATORY OFFICE, 9307 SOUTH WADSWORTH BOULEVARD
LITTLETON, COLORADO 80128-6901
May 5, 2023
SUBJECT: Nationwide Permit Verification – Corps File No. NWO-2022-00707-DEN,
Dry Creek No. 3 at Baseline Road Culvert Replacement
Dave Webster
Boulder County Public Works, Engineering Division
2525 13th St., Suite 203
Boulder, CO 80304
Dear Mr. Webster:
This letter is in reference to the proposed project located at approximate latitude
40.0001166480887, longitude -105.191018822654, in Boulder County, Colorado. The
work as described in your submittal consists of replacing an existing 20 feet by 5 feet
box culvert in Dry Creek No. 3, underneath Baseline Road, with a double 18 feet by
10.5 feet cast-in-place concrete box culvert with headwalls and wingwalls. One box
culvert is designed to convey the main channel and the second box culvert will provide
overflow conveyance and a potential trail extension in the future. The project also
includes minimal creek re-alignment to allow better flows to the proposed structure, and
wetland vegetation re-establishment. Fill material placed in waters of the U.S. includes
299 cubic yards of concrete for the culvert and wingwalls, 271 cubic yards of soil riprap,
84 cubic yards of relayed riprap, 188 cubic yards of culvert embankment material, and
30 cubic yards of wetland topsoil in Dry Creek No. 3 and adjacent wetlands.
Based on the information provided, this office has determined that the work is
authorized by the Department of the Army Nationwide Permit (NWP) NWP 14 Linear
Transportation Projects, found in the January 13, 2021, Federal Register. Enclosed is
a fact sheet, which fully describes this Nationwide Permit and lists the General
Conditions, and Colorado Regional Conditions, which must be adhered to for this
authorization to remain valid. In addition, the following Special Conditions must be
followed:
1.To ensure your project complies with the Federal Endangered Species Act, you
shall implement all of the mitigating measures proposed as part of your project
description, which are identified in the enclosed U.S. Fish and Wildlife Service
letter of concurrence (2022-0036244, dated April 21, 2023). If you are unable to
implement any of the proposed measures, you shall immediately notify this office
and the U.S. Fish and Wildlife Office so we may consult as appropriate, prior to
initiating the work, in accordance with Federal law.
Item 3B - WET2022-00007
- 2 -
Although an Individual Department of the Army permit will not be required for this
work, this does not eliminate the requirement that any other applicable federal, state,
tribal or local permits be obtained as required. Please be advised that deviations from
the original plans and specifications of this project could require additional authorization
from this office.
The applicant is responsible for all work accomplished in accordance with the terms
and conditions of the nationwide permit. If a contractor or other authorized
representative will be accomplishing the work authorized by the nationwide permit on
behalf of the applicant, it is strongly recommended that they be provided a copy of this
letter and the enclosed conditions so that they are aware of the limitations of the
applicable nationwide permit. Any activity which fails to comply with all the terms and
conditions of the nationwide permit will be considered unauthorized and subject to
appropriate enforcement action.
This verification will be valid until March 14, 2026. If work has begun, or is
under contract to begin, prior to March 14, 2026, the permittee is granted an
additional 12 months to complete the project under the 2021 NWP. In compliance
with General Condition 30, the enclosed “Certification of Completed Work” form
(blue) must be signed and returned to this office upon completion of the
authorized work and any required mitigation.
If there are any questions, please feel free to contact Cody Wheeler at (720) 922-
3846 or by e-mail at Cody.S.Wheeler@usace.army.mil, and reference Corps File No.
NWO-2022-00707-DEN.
Sincerely,
Kiel Downing
Chief, Denver Regulatory Office
Enclosure(s)
Copies Furnished:
U.S. Fish and Wildlife Service
Colorado Department of Public Health and Environment
Environmental Protection Agency
Colorado Parks and Wildlife
Tim DeMasters, Corvus Environmental Consulting
Item 3B - WET2022-00007
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