THE LAKE MANITOBA PROBLEM:
AN INVITATION TO ACTION
Stakeholders are concerned over recent and future impacts on the many natural resources, including the shorelines, lakeside marshes, beaches, farmlands, fish and wildlife - and economic activities such as tourism, cottage development, lodge and outfitting operations, commercial and sport fishing, trapping and hunting in Lake Manitoba. This extends to Lakes Winnipegosis, St. Martin and Pineimuta as well. Although there have been several local meetings and provincial hearings concerning management of this system over the last forty years, the lakeís natural resources continue in a state of decline.
Manitoba Water Resources formally requested this summer that Manitoba government strike a commission to investigate these concerns and prepare for hearings in the near future. The Government has not responded to date but is expected to some time in 2001. The Lake Manitoba Basin Initiative (LMBI) was formed by a group of concerned citizens, sportsmen and landowners who want to encourage improvements in the control of Lake Manitoba water levels and quality. Wayne Cowan, of W.C. Rural Resources Inc., was hired to collect and share information on historical and present operation of the Fairford Dam and Assiniboine Diversion, local drainage and other activities that impact the lake system, through documentation and discussions with stakeholder groups like yourselves and resource managers.
What Have We Learned?
There have been surprisingly few studies of the impacts of these major works even though there were early indications of potential problems, especially in the south basin and Lake St. Martin - Pineimuta. Since construction of the Fairford River Dam in 1961 and the Assiniboine River Diversion in 1970, there have been many reports of dysfunctional lake levels and water quality, and deterioration of the associated marshes, beaches, shorelines, vegetation, fish and wildlife by the people who live around the lake and use its resources. Yet there has been very little investigation to determine their validity or to ensure against increasing damages.
Research into past studies, observations and documentations, and discussions with large numbers of stakeholders from all around the lake, and with associated resource managers and academics, has revealed a number of factors we need to address and learn more about in order to make intelligent, informed decisions that will improve the health of the lake system. Please consider:
- The Fairford Dam is operated to maintain an average 812.17 feet above sea level year round. The resulting stabilized lake levels are blamed for excessive erosion of south basin shorelines, beaches and marshes, additions of sediment to the lake waters and destruction of aquatic vegetation and beach ridge trees.
- The Assiniboine Diversion began operation in 1970 to reduce flood damages down stream and in Winnipeg. It has operated during 19 of the last 30 years. During wet years, it injects massive amounts of water into the lake and, in some years, flows April to August. Compounding this increased inflow is the slumping of the Fairford Dam so that the logs cannot be removed, in three of the bays. The result is the Dam can handle less than (estimated) half the intended volume of flows; such that the lake may in some years remain unnaturally high into autumn.
The Assiniboine Diversion also flushes great amounts of uprooted vegetation, sediment, organic materials and algae into the lake. In 1974 and 1976, 684,000 tons and 500,000 tons, respectively, of sediment were estimated to enter the floodway from the Assiniboine River and about half these loads flowed into Lake Manitoba. Add to this tons of uprooted vegetation and farm chemicals. One early study showed levels of organic phosphate in the Diversion higher than those in the lake, as well as loads of nitrates, algae and other elements.
A 1995 study by Manitoba Environment compared changes in water quality near Delta Beach between 1973-1977 and 1991-1995. They found increases in concentrations of chlorophyll, which cause periodic algae blooms, phosphate which also stimulates algae growth, and turbidity.
In most lakeside marshes, loss of emergent and submergent vegetation, increased turbidity and mucky bottom, and the filling of channels and sloughs with silts and cattail growth are ongoing. These changes are often intensified by sediments from the Diversion and rooting activity by carp. Waterfowl, furbearer and fish populations and productivity have been greatly reduced in many of the marshes.
In some lakeside marshes that were diked into cells and managed to emulate natural water levels, waterfowl and muskrat populations are thriving. The water is clear and the vegetation communities are healthy inside the cells while quite the opposite is true in the open marshes adjacent.
There have been shifts in the species of harvested fish since inception of the Dam; however, they may be correlated with other factors such as fishing regulations, use of smaller net sizes and market demand. In recent years, the decline in sauger populations could be due at least in part to increased spring silting of eggs.
In Lake St. Martin - Pineimuta since inception of the Fairford Dam, summer flooding is a common occurrence while winter fishing is often disrupted by inadequate flows or sudden flushes of water.
- Waterfowl populations in the south basin marshes in fall have declined over recent years, resulting in a decline in hunting opportunities and sports related economic opportunities in the area. However, the few marshes that are segmented and managed do supply satisfactory hunting opportunities.
Sport fishing, a prime activity in Delta Marsh for many years, declined rapidly beginning in the 1940ís when man began manipulating the marsh entrances and lake levels. It has remained very poor for the last 50 years.
- Muskrat production on the south basin marshes, Pineimuta and Lake St. Martin has plummeted to historically low levels. Trappers are just giving up.
Many of the concerns were commonly shared among the people from all vocations related to the lake's resources:
- The rules of management of the Fairford Dam should be loosened to allow more fluctuation in water levels to simulate natural seasonal lake levels, as well as to provide the extended annual high and low regimes that occur during drought and wet periods.
- The Dam and downstream channel are not capable of managing large flows.
- The Assiniboine Diversion should only be used when necessary, and then be opened slowly in flood years, so as to reduce the sediment and vegetation loads entering Lake Manitoba.
- Delta area stakeholders and users feel the Diversion floods and sediments Delta Marsh excessively; they ask that the flows be controlled so that there is no more breaching of the channel banks in future.
- With stabilized water levels, the beach ridge trees are being lost and the beaches are not being rebuilt as they did during low water years under the natural regime.
- No precise water levels were advised however; there was almost unanimous agreement that a return toward a more natural lake regime should be attempted. Allow periodic draw down and flood-up to re-establish marsh and shoreline vegetation and beach ridge trees, irrigate haylands and fill perched basins. Seasonal flows should emulate the natural regime: high levels in spring, followed by slow draw down over summer and a stable level over winter.
- The Fairford Dam should be repaired and the downstream channels improved.
- Manitoba Water Resources should develop models of alternative water regimes that consider the relative impacts on all natural resources in and around the lake.
- There is great concern over polluting the lake, especially from the Assiniboine Diversion but also from the proliferating drainage from all around the basin. This could extend to land use practices throughout the Assiniboine River basin, including Saskatchewan. The Diversion should be opened in heavy flood years only and operated for as short a period as possible. Earlier and more intensive action is needed to weaken the ice at the outlet to the lake so that the Diversion can be opened earlier and more slowly, the initial flow slowed so it carries less sediment and detritus.
- All drains and streams flowing into Lake Manitoba should be assessed and action taken to reduce the content of sediment and organic materials.
- A full-scale study should be initiated to evaluate the present state of the lakesí resources and determine appropriate measures to improve those that require it. This includes water quality, algae growth, shoreline and marsh vegetation, haylands, beaches, and invertebrate, fish and wildlife species in Lakes Manitoba, Winnipegosis, St. Martin and Pineimuta.
- Studies should be undertaken to evaluate the present state of economic activities derived from the lake resources and derive ways to improve them.
No significant changes should be made in the present regime until the studies provide enough information to allow informed decisions to be made.
Invitation to Action
The Lake Manitoba Basin Initiative hopes this information is of value to all interest groups and all stakeholders. They now invite all concerned to join in a coordinated program to gather the information you suggested was required and to proceed to resolve the several impacts on the Lake Manitoba system, as outlined in the report. In this action, all interested parties would obtain a common understanding of the issues and devise a coordinated approach. Assignments of tasks to each group will be made eventually. The end result should be great improvements in the health of the lake system, its resources and aesthetic, environmental and economic benefits for all Manitobans.