Canoga Creek Conservancy
Canoga Creek Marsh Wetlands Enhancement Initiative
USDA/NRCS Wetland Reserve Program
USFWS/ Partner for Wildlife Program
New York State Dept. of Environment and Conservation
Seneca County Soil and Water Conservation District
Cayuga County Soil and Water Conservation District
Cayuga Lake Watershed Network
New York Corporate Wetlands Restoration Partnership
Cornell University Department of Natural Resources
Tidball Private Land and Canoga Marsh Wildlife Management Area
Project Description and Purpose
Scott Jones (Habitat-NYSDEC), Art Kirsch (Wildlife-NYSDEC) and Jim
Ronald J. Vanacore, USDA/NRCS
Keith G. and Moira M. Tidball - Canoga Marsh Wetland Reserve Program
(T) Fayette, Seneca County
Category of Activity: New construction - wetland enhancement.
Freshwater Wetland UN-1, Class I, 134.4 acres.
Type of Activity: Construction of open water areas (potholes and level
ditches) in a freshwater, non-tidal marsh.
Type of Materials and quantities: (See description below and attached
figures.) All material will be found on site. A long-reach (50' or better)
excavator and floatation mats are recommended to accomplish the
construction. Less than 20% of the wetland will be directly affected by the
Work Area dimensions: Restoration is planned for approximately 70 acres
of freshwater marsh: 35 acres on private property (Tidball) and another,
adjacent 35 acres on public property known as the Canoga Marsh Wildlife
Management Area (New York State Department of Environmental
Conservation). These sites are adjacent and are located on the west side of
Cayuga Lake, in the County of Seneca and Town of Fayette. (See also
description below and attached figures.)
Need or Purpose Served:
The purpose of this proposed project is to restore lost wetland functions
(primarily wildlife use) on adjacent lands; one private and one owned by
NY State. Potholes and level ditches will be constructed to create openings
in a degraded, freshwater, non-tidal wetland for enhancement of habitat
value for migrating and nesting waterfowl, marsh birds and muskrats.
Plant diversity in the marsh will be increased by reestablishing hydric
conditions that will encourage the growth of submerged aquatic vegetation
in the potholes and level ditches. Amphibians and macro-invertebrates
will benefit from the construction of several fish-free potholes near shore.
Waterfowl will find suitable brood rearing habitat. Visibility of wildlife will
improve in some sections of the project for public enjoyment and
educational opportunities. A personal commitment will be made by the
private land owner (Tidball) to habitat improvement and management.
Public access will be encouraged on the public lands (Canoga Marsh WMA)
and the project will serve as a demonstration area for wetland
Alternative options for design are limited. The option of doing nothing is
not preferred due to the poor condition of the marsh. The amount of
enhancements are limited by funding. The location of the enhancement are
not significant (other than what is described herein) due to the lack of
diversity and water depth in the wetland. Construction of a berm with an
option for a water control structure would allow more management of
water levels but would require filling and be too costly.
Site and Project Description Detail:
Easily detected along the project area at a type and elevational change
between cattail marsh and agricultural field. Attached maps show
approximate boundary. Boundary will be flagged by NYSDEC prior to
The wetland in the project area is a Class I, 134.4 acre, degraded, dense
monocultural cattail marsh with limited open water throughout. At the
Cayuga Lake open water- and marsh- interface there is a steep, 1- to 2-
foot vertical drop at common lake levels, that restricts accessibility by
wildlife. Purple loosestrife is present throughout the marsh, but not
dominant. The upland fringe of wetland includes a small area of burr reed
(purportedly an old pond, since filled in by eroded silts from adjacent
agricultural fields), silky dogwood, green ash saplings, willows, and several
distinct areas of mature green ash and cottonwood. Substrates within the
cattail marsh are hydric organic soils, characterized in the Seneca County
Soil Survey as: shallow, inundated areas around lakes and ponded areas,
bottom-land and alluvial deposits, covered by water most of the year.
The adjacent, upland area on the Tidball property is almost entirely in row
crop production (soybeans in 2003, corn in 2004 and 2005). Two well-
defined erosion gullies are present, flowing eastward to the wetland
boundary. The drop off from upland to marsh is steep (1 to 1 slope) and
ranges from 4 to 8 feet.
A path from the agricultural field to the lake exists at the northern
property boundary and is used by the owner to access the lake for hunting
and recreational purposes. This path was apparently established on old
fill, is presently mowed to the lake, and is suitable for both pedestrian and
seasonal off-road vehicle use.
The area adjacent to the marsh on Canoga Marsh WMA is forested in pole
stage green ash and red maple.
This NRCS Wetland Reserve Program Project is to consist of potholes and
connecting level ditches within the wetland proper, limited clearing of
shrub/sapling vegetation at upper margin of wetland and small portion of
the 100-foot adjacent area, and nesting cover establishment (native
grasses) in and upland of the adjacent area on the Tidball property.
Grasslands are to be maintained by periodic mowing, on 3-year cycle.
Grass waterways, which will be mowed annually, are to be established to
stabilize the erosion gullies. No changes will be made to the adjacent area
on the Canoga Marsh WMA.
About 15 to 20 connected enhancements (shallow-water potholes and
connecting level ditches) will be established along the eastern third of the
Tidball cattail marsh and along the north side of Canoga Creek on the
State land to provide access to water for marsh birds, ducks and muskrat.
To encourage fish-free pools for amphibians, near-shore potholes will also
be constructed but will not be interconnected, or connected to lake water
or the eastern excavations. The spoils from the near-shore pothole
excavations will be removed from the wetland proper to the greatest
extent practicable. Spoils from the eastern region of the Tidball cattail
marsh and southern region of the State marsh will be scattered in shallow
depths within the wetland, near each excavation. Depths of these spoils
will be scattered no greater than 10 inches during construction and will
likely subside to 6 to 8 inches, keeping the soil drainage classification for
the affected areas as ‘very poorly drained’. Seeding and mulching of
disturbed areas will be done immediately to reduce colonization by
invasive species, provide protection before natural vegetation becomes
established, and prevent erosion.
Our goal for the enhancements is not to create dry, above-grade islands in
the marsh, but rather to have the spoil piles subside to saturated
conditions to allow native hydrophytic plants to reestablish. The
excavated surface areas will range from 15,000 to 20,000 square feet and
be irregular in shape to maximize edge effect and provide wildlife cover.
The potholes will have a 4-foot maximum depth and bottoms will be
irregular and varied. A minimum of 2/3rds of the surface area will be 6 to
18 inches deep. Pothole side slopes will be gentle with a minimum of 50%
of side slope area being at a grade of 6:1 (horizontal to vertical) and the
remaining side slopes of 3:1 or flatter. Submerged islands will be
incorporated into the design.
Typical cross-sections for the enhancements are difficult to show in a
sketch because they will be variable, but refer to Figure 7 (Typical pothole
and level ditch cross section) for a general, maximum-size depiction.
When potholes are connected by level ditches, the ditches will have an
excavated depth of 2 to 3 feet, a width of 4 feet and a side slope of no
steeper than 3:1. Spoils will be handled in the same manner as spoils from
The spoil piles from the potholes will begin at approximately 10 feet from
the excavation and have a width (from above) of 25 to 75 feet. Cubic feet
of spoil will vary with the size of the excavation. A simple approximation
is that the average depth of the excavation will be 2 feet. Consequently,
the cubic feet of spoil will be twice the surface area, or, for example 40,000
cubic feet for a 20,000 square foot (100' by 200') excavation. Spreading the
40K cubic feet of spoil to an initial depth of 10 inches results in a surface
area of 33,333 square feet. The spoil will be side-cast with a long-reach
(50-foot) excavator to a width of 50 to 70 feet, resulting in a linear
(perimeter) distance of 555 feet (or 92% of the 600-foot perimeter).
If 20 potholes are created at a square footage of 20,000 sq. ft. (the
maximum for this project) and 2,500 feet of level ditch is created, there
will initially be 450,000 square feet of open water added to the 134.4 acre
marsh. This amounts to 7% of the surface area. As emergent vegetation
(primarily Typha spp.) colonizes the shallow edges, this percentage of open
water will drop to about 2%. The local affect of this seemingly small
addition of open water will be augmented by encouraging emergent plant
control by herbivores (primarily muskrat).
The volume of spoil generated during construction will be 900,000 cubic
feet. About 1/4 of this, or 225,000 cubic feet will be removed from the
wetland. The remaining 675,000 cubic feet will be side-cast and spread
over approximately 15 acres or 11% of the 134.4 acre marsh.
The willow fringe on the southern portion of the Tidball property and the
green ash sapling/silky dogwood thicket in the center of the property and
near the northern boundary will be cleared and removed to allow wildlife
access from marsh/open water enhancements to upland nesting cover,
primarily for nesting waterfowl. Two small stands of more mature trees
will be left to maintain habitat diversity for non-waterfowl wildlife and to
Nesting cover will be planted on the Tidball property by converting the
entire agricultural field to warm-season, cool-season mixed grassland,
exclusive of 2 cool-season grass waterways. This site and soils are suitable
for warm-season grass establishment. This habitat type will provide
valuable nesting cover for waterfowl and grassland bird species.
Landowner planted corn and used Atrazine in 2005 to reduce broadleaf
weed competition with planted grasses. Recommend mowing on 3-year
cycle (1/3 per year) and that mowing be done after July 15th and before
August 15th, only.
Erosion control in the gullies and waterways will be made by regrading
and planting cool-season grasses to stabilize these areas. Annual mowing
to keep woody stems from encroaching in these waterways is
Threatened & endangered plants (shagbark hickory and southern naiad)
were not observed in the project area. The existing cattail marsh would
seem to be an unlikely location for southern naiad, a submerged aquatic
species, due to the limited open water and dense cattail coverage. It may
occur within the limited existing open water areas. Development of
additional open water areas (potholes & level ditches) may provide
additional locations for the establishment of this plant. It is unlikely that
the project will have an adverse impact on southern naiad.
Mr. Tidball may wish to construct a cottage or other building outside the
easement boundary near the north property line. It is understood that any
proposed future development be located outside the 100-foot adjacent area
and the Department should be contacted to discuss or to delineate the
wetland boundary prior to planning any development.
Public access will not be a requirement of this restoration project on the
private (Tidball) property.
Timing and Post-project Notes:
The establishment of native grasslands on the upland Tidball property has
been completed in May, 2006. The wetland enhancements should be
accomplished during late summer or fall to avoid nesting birds.
Monitoring of the condition of vegetative growth on the spoils is a
requirement of this project. The NYSDEC will provide this service. No
phragmites (invasive, common reed) was observed in the immediate
vicinity of the project site and are therefore not a significant risk. Purple
loosestrife is common and will readily colonize any disturbed areas.
Loosestrife establishment may be reduced by immediate seeding disturbed
areas. Introduction of Galerucella beetles to control loosestrife on both
sites, is recommended. NYSDEC at Northern Montezuma WMA, 1385
Morgan Road, Savannah, NY is a source of Galerucella beetles.
Research shows that agricultural grasslands interspersed with abundant freshwater wetlands and
tributaries creates habitat conditions that are critical to waterfowl and other migratory birds. Some
ducks build their nests in dry grassy areas rather than in marshes, so it is important that habitat projects
include both grassy areas and wetlands. The more acres of grass available for hiding a nest, the more
likely it is that the eggs in a duck nest will hatch rather than be destroyed by predators.