HomeMy WebLinkAboutHEARTHFIRE PUD, 1ST FILING - FINAL - 31-95D - SUBMITTAL DOCUMENTS - ROUND 1 - WETLANDS DOCUMENTS5.0 EXISTING POND MITIGATION
The exiting pond is a shallow pond that is maintained by irrigation
water and groundwater. It is proposed that the pond can be
enhanced, both aesthetically and for wildlife purposes, by
deepening a portion of the pond, and using the dredge spoils from
the deepening to create a waterfowl nesting island Figure 3). By
deepening a portion of the pond, along with shallow water areas,
wetlands, and an island waterfowl habitat would be improved.
In addition 0.30 acres of wetlands will be created at the south
edge of the pond. The design plan would follow that as outlined in
Section 3.0
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4.0 WETLAND MONITORING
Following the restoration efforts the wetland mitigation area
would be assessed for the effectiveness of the project for three
growing seasons. The observations would occur at in June and
September of each growing season. The status and effectiveness of
the wetland mitigation would be evaluated and the results would be
reported to the City of Fort Collins and the U.S. Army Corps of
Engineers.
Measures that would be monitored include vegetation establishment,
and hydrology of the site.
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Excavation and Grading
The topsoil and subsoil, along with the vegetation, would be
excavated and cast to the upland side of the excavation area.
During excavation the upper 12 inches of topsoil would be
segregated from the subsoil. The topsoil and subsoil would be
stockpiled separately within the upland. The soils would be
removed to final grade specifications as described in the final
engineering plans.
3.3 Wetland site Design
The conceptual design plans, shown in Figure 2.
The wetland mitigation plan, in some areas, is designed to re-
create the same elevation of the impacted wetlands. Establishment
of site hydrology that provides sufficient water at the frequency
and duration required for wetlands vegetation and a pond is the
key to successful wetlands creation projects. The goal for the
design plan is maintenance of soil saturation and surface
inundation. Hydrologic conditions at the site are presently
maintained by groundwater. Purchased surface water would aid in
the maintenance of the wetlands (and associated created pond).
3.4 species Composition for Wetland Planting
It is proposed that emergeni, wetland plants would not be planted
within the mitigation area, but that the wetlands would be allowed
to naturally revegetate from nearby propagule sources, and the seed
bank from the applied topsoil from the. wetland that would be lost
from construction of the roadway and pond. The sloped wetland
mitigation area would be hydroseeded with fast growing grass
species for soil erosion purposes.
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3.0 WETLAND CONSTRUCTION
3.1 surveying
No excavation within the wetland mitigation area would be started
until the wetland mitigation area has been surveyed and staked, and
an engineer has obtained elevations and measurements of the ground
surface. The information would be utilized in the development of
the final grading plan. The final grades would be verified by the
engineer following excavation.
3.2 Earthwork
This item covers clearing, excavation and grading, disposal,
placement, topsoiling and compaction of all materials within the
limits of work required to construct 1.92 acres of emergent
wetlands and 1.44 acres of open water. Grading Plan cross sections
will be provided in the final engineering design.
Vegetation Clearing
The initial step in the implementation of the mitigation plan is
the clearing of existing vegetation. Cleared vegetation would be
disposed of on -site and adjacent to the mitigation areas. The
vegetation would be spread on the upland landscape. Areas not to be
cleared would be clearly staked so that such areas would be
recognized and not damaged during the construction process.
A
* Provide for future replacement of undesirable species,
specifically Russian olive (Elaeagnus angustifolia); and
* Creating a pond with the created wetlands;
* Deepening a portion of the exiting pond and creating an
island.
* Creating 0.30 acres of wetlands at the south end of the
exiting on -site pond.
This document provides a conceptual design for maintaining the
wetland hydrology, soils, and vegetation at the wetland mitigation
area, as well as maintaining a seasonal water body.
Wetlands
The mitigation plan details the vegetation to be planted. The
hydrological functions will be obtained by excavating to existing
wetland elevations, enabling surface water inundation and soil
saturation to occur in the excavated areas. If the compensation
goals are not fully achieved during implementation, modifications
to the plan can and will be made. Once constructed, data will be
collected and submitted in monitoring reports to the City of Fort
Collins and the U.S. Army Corps of Engineers.
Created Pond
The created pond will
groundwater. In addition,
ensure the water body is
be excavated to the
surface water inputs
maintained at a four
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seasonal depth of
will be provided to
foot depth.
HEARTHFIRE SOUTH
DELINEATION OF WETLANDS
AND POND
FIGURE 3
SITE OF DEVELOPMENT - 106 ACRES
1 ACRE OF EXCAVATION TO COME
FROM BOTTOM OF EXISTING POND
TO CREATE APPROX..5 AC ISLAND
M LIM IR
■
i
HEARTHFIRE NORTH -
WETLAND IMPACTS
AND MITIGATED
WETLANDS
FIGURE 2
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SCALE 1:24 000
1 0 1 MILE
I ODO 0 1000 2000 30M 4000 5000 6DD0 7000 FEET
+ 1 5 0 1 KILOMETER
CONTOUR INTERVAL 10 FEET
DOTTED LINES REPRESENT 5-FOOT CONTOURS
NATIONAL GEODETIC VERTICAL DATUM OF 1929
T111S MAP COMPLIES WITH NATIONAL MAP ACCURACY STANDARDS
FOR SALE BY U. S. GEOLOGICAL SURVEY, DENVER, COLORADO 00225, OR RESTON. VIRGINIA 22092
A FOLDER DESCRIBING TOPOGRAPITIC MAPS AND SYMBOLS IS AVAILABLE ON REQUEST
VICINITY MAP
FIGURE 1
WETLAND MITIGATION
HEARTHFIRE PUD
FORT COLLINS, COLORADO
1.0 INTRODUCTION
The Richards Lake Development Company (RLDC) is proposing a
development (Hearthfire PUD) on the north edge of Richards Lake in
North Fort Collins, Colorado (Figure 1).
Within the development proper, approximately 0.5 acres of "Waters
of the United States" (Waters) would be impacted by deepening a
pond and creating a small island within the pond from the dredged
material (Figure 2).
An access roadway into the development would impact approximately
1.00 acres of wetlands The wetlands that would be impacted are
dominated by narrowleaf cattail (Typha angustifolium) (Figure 3).
In order to mitigate the lost wetlands to RLDC has prepared a
wetlands mitigation plan to compensate for the habitat value of
wetlands lost from the construction of the roadway. In addition,
RLDC will create a pond with the wetlands. Mitigation for the
exiting pond is through enhancement, by deepening the pond in one
area and creating a wildlife habitat island. Also 0.30 acres of
wetlands would be created at the south end of the pond.
The overall goals of the mitigation plan includes the following:
* Compensate lost wetlands at a 1.5:1 ratio;
* Create wetlands within the area where wetland would be lost;
* Maintain existing hydrological processes;
* Provide habitat for species displaced by filling of
wetlands;
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Existing Pond and Associated created Wetlands
A portion of the existing pond will be dredged to a greater depth,
with the dredge spoils being used to create a wildlife habitat
island. Wetlands associated with the pond will not be impacted. In
addition, 0.30 acres of wetlands will be created at the south edge
of the pond.
ILI
2.0 EXISTING SITE DESCRIPTION
The development proper is within the City of Ft. Collins, while the
access road is in Larimer County, but within the Fort Collins Urban
Growth Boundary (Figure 1).
The access road site was, at one time, a small irrigation holding
pond, that drained into the exiting on -site pond. The exiting pond,
in turn, once drained into Richards lake.
The wetland areas that would be impacted by the access road are
dominated by narrowleaf cattail, an obligate wetland species.
The soils, as mapped by the Natural Resources Conservation Division
(formerly the Soil Conservation Division) for both the access road
and existing on -site pond are mapped as WATER (NRCS (SCS) 1980).
Site -specific hydrologic data for both the wetlands and pond are
limited or non-existent. It appears that groundwater, at this time,
is the main source of hydrologic input for the wetlands, with
irrigation water and groundwater being the primary hydrologic
inputs for the pond. In the past, water from the Larimer ditch was
diverted into the wetland area and the pond.
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