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
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 Friends.
The results of this initial phase of restoration included many benefits. The project galvanized the community in support of wetland rehabilitation. Government, 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 productive.
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.
Phase 2
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 Resources (OMNR).
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 general.
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.
Activities 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 hand.
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.
