In 1992 a two-phased Marsh Management Plan
was proposed by Environment Canada, through the Canadian Wildlife
Service. This concept would showcase Second Marsh, open it to the
public, and attempt various experimental restoration measures. Wetland
rehabilitation techniques are grouped into four categories: hydrologic,
sediment related, contaminant and biological.
As a result of
our demonstrated leadership, Friends
was formally given responsibility for delivering educational and
stewardship programs in the spring of 2000, through the City of
Oshawa's Second Marsh Management Model. Through its programs, Friends
promotes the natural heritage value of wetlands and fosters an appreciation
for Second Marsh. The Management Model is overseen by a management
committee which includes a representative from the Ministry of Natural
Resources, Aurora District.
Phase 1 of the Marsh Management Plan
From 1993 through 1996, Phase 1 of the Second
Marsh restoration was implemented. Many innovative measures
were undertaken, including changing the outlet back to the west side
and building flow deflection islands to assist with silt removal.
While these and other steps were moderately successful, they did not
fully correct all of the problems facing the future of the wetland.
This $1.3 million initiative was lead by
Environment Canada, Canadian Wildlife Service, under the direction
of Nancy Patterson, in partnership with the City of Oshawa and
The results of this initial phase of restoration
included many benefits. The project galvanized the community in
support of wetland rehabilitation.
industry and the private sector came together in support of this
major restoration effort. During this time much was accomplished.
Walking trails, boardwalks, and raised viewing decks were built,
interpretive signage was installed and other amenities were added.
Each of these attributes was designed to introduce and educate people
to the values of wetlands.
However, when the first phase of the restoration
was completed, the goals and objectives of the 1993 Management Plan
were not completely met. This was due largely to three factors that
continued to stress the health of the wetland ecosystem;
Water Quality: Land use practices associated with both the
rural, and the rapidly expanding urban portions of the upstream
watersheds have exacerbated soil erosion and resulted in excessive
sediments suspended in the watershed inflow to the marsh. The
resulting poor water quality has limited the recovery of the
submergent vegetation communities that were once lush and quite
Water Depths / Fluctuations: Lake Ontario water levels also
impact the wetland and precludes the natural dynamic fluctuations
that would have once brought drawdown type events, and thus
periods of rejuvenation, to the marsh. In-basin water depths,
even during extreme record low Great Lake water level events
are not sufficient to provide conditions conducive to the germination
and subsequent establishment of aquatic emergent plant communities.
Carp: Large numbers of Common Carp have a significant negative
impact on the already fragile wetland ecosystem. In addition
to the rooting and feeding activities on any established plant
material, the carp assist with the re-suspension of silt and
clay sediments. Both of these impacts combine to further reduce
the potential of the wetland habitat to recover.
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2 of the Marsh Management Plan
In April 2000, Ducks Unlimited Canada, a private,
non-profit, international wetland conservation organization was given
responsibility for Phase 2 of the wetland restoration project under an
organization frame-work initiated by the City of Oshawa.
Today, Ducks Unlimited Canada manages the
restoration project in concert with the City and other Second Marsh
partners that includes the Friends of Second Marsh, Canadian
Wildlife Service - Environment Canada, Central Lake Ontario
Conservation Authority (CLOCA) and the Ontario Ministry of Natural
Friends' role has evolved over the years.
In the 1970's and 1980's, the SMDA focused on saving the marsh from
habour development. In the 1990's, Friends played a lead role
in Phase 1 of the restoration program. After Ducks Unlimited Canada became
involved in the restoration efforts, Friends has taken on a
supportive role in restoration work, and its primary focus has
evolved to an education and stewardship role that engages the
community to appreciate the values of Second Marsh, and wetlands in
Under the director of Owen Steele, Project
Manager, Ducks Unlimited Canada, the second phase of restoration was
initiated in the winter of 2001.
The Ducks Unlimited Canada Phase 2 Restoration
consisted of the following initiatives:
Creating a natural channel to re-route the
inflow of Harmony Creek around the Second Marsh directly into
Lake Ontario to help remove poor water quality from the Marsh
by removing the sediment-laden water entering the wetland.
Constructing an earthen dyke (1500 lineal
metres) along the west side of the Marsh to help ensure the
water remains within the new channel without entering the Marsh
during high water periods. This will result in a significant
improvement to water quality within the marsh thus enhancing
the growing conditions for submergent aquatic vegetation.
Closing the existing outlet to Lake Ontario
and installing a two-way pump on the existing barrier beach
to provide adequate water level management and offset the impact
of the higher and stabilized Lake Ontario water regimes. This
will accommodate both a temporary dewatering to encourage the
germination of aquatic plant species and water augmentation
to ensure their healthy establishment.
In order to successfully realize these benefits
a fish passage structure was installed part way up the basin
at the former Harmony Creek inlet to the marsh. The fish passage
structure will also facilitate a passive water level control
function, while at the same time exclude the passage of the
large Common Carp that will seek entrance into the marsh. The
restored wetland habitat will provide significant benefits as
spawning, nursery and foraging habitat for warm water fish species.
Interim monitoring during Phase 2 Restoration
in 2002 documented an approximate 7-fold increase in submerged aquatic
plant growth due to improved water quality. There was also an expansion
of emergent aquatic plants into the open water portion of the wetland
that was historically vegetated. Also noted in 2002 was the first breeding
record of Ruddy Duck for Second Marsh. In 2003 we
established first breeding for Caspian Terns and Trumpeter Swan.
Contractors to the CWS conducted spring migration
counts for the Little Gull in 2002 and found numbers as high as
114 on Apr. 29 and May 2; this represents approximately 26% of the
estimated total North American population.
Additional Restoration Components
The restoration of Second Marsh will continue
in 2004 as the marsh receives some finishing touches in 2003.
Ducks Unlimited Canada (DUC) oversaw the restoration plans on behalf
of the City of Oshawa and the other project partners including Friends
of Second Marsh, Environment Canada, Ontario Ministry of Natural
Resources and Central Lake Ontario Conservation Authority. DUC will
continue to lead the restoration efforts throughout 2003.
scheduled for 2004 include some trimming of the rough sections of
dike, the removal of silt fences, and the monitoring of re-vegetation
efforts. In addition, the restoration of the wetland habitat of
Second Marsh will begin in the early spring period with the initiation
of the de-watering of the marsh. The de-watering is undertaken to
mimic the natural ecological processes that maintain wetland productivity
and health. Unfortunately, the regulation of Lake Ontario water
levels has had a previously negative impact on the dynamic nature
of the water levels within Second Marsh that typically keeps a wetland
vibrant and healthy. Regulated water levels continue to limit the
marsh's ability to thrive, and therefore nature needs a helping
The de-watering will promote natural processes
such as the recycling of nutrients back into the marsh soil and
the germination of emergent aquatic plant seed that have been laying
dormant on the bottom of the marsh awaiting just such conditions.
Monitoring of the de-watering results will be conducted throughout
the summer growing season and the water will be returned to the
marsh in the early fall.
Additional components of the restoration project
will include future enhancement of watershed stewardship within
both the Harmony and Farewell Creek sub-watersheds, promotion of
educational programs at the marsh and continued environmental monitoring
of the wetland and its wildlife communities. These activities will
be undertaken through the Second Marsh partners and the framework
developed by the City.
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