St. Clair River Ecosystem Summary White Paper and Report
Evaluation of Potential Ecological Impacts Resulting from Lake Michigan‐Huron Water Level Restoration and the Placement of Structures in the St. Clair River
International Upper Great Lakes Study Ecosystems Technical Working Group Scudder D. Mackey, Ph.D. ETWG Project Manager March 2011
Photo Courtesy: David Bennion, USGS
Lake Sturgeon Spawning Habitat near Bluewater Bridge, Upper St. Clair River
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St. Clair River Ecosystem Summary White Paper and Report
Evaluation of Potential Ecological Impacts Resulting from Lake Michigan‐Huron Water Level Restoration and the Placement of Structures in the St. Clair River
Executive Summary The results of this work indicate that potential St. Clair River environmental issues related to placement of water control structures on the bed of the St. Clair River are significant. A comparison of potential benefits versus environmental impacts to the St. Clair River will show that: • • •
Local environmental impacts will be severe; Regulatory requirements are complex; and A long time frame (35 to 45 years) is required to implement the project and will negate many of the anticipated benefits.
Key environmental findings include the identification of critical fish habitat for endangered species located at the headwaters of the St. Clair River near the Bluewater Bridge. These areas represent the most significant lake sturgeon spawning habitat in the Great Lakes, and are coincident with the areas selected for placement of multiple submerged sills near the headwaters of the St. Clair River. Anticipated impacts to lake sturgeon spawning habitat are anticipated to be negative, and alternative locations downstream were deemed to be too shallow as these submerged water control structures may impede navigation.
Potential lake sturgeon spawning habitat restoration sites have also been identified near Stag and Fawn Islands, and are coincident with the areas selected for placement of water control structures in the side channels east of Stag and Fawn Islands. Moreover, contaminated sediments are located along the eastern (Canadian) shoreline of the St. Clair River near Stag Island and there is increased risk for disturbance and resuspension of contaminants due to construction activity and/or localized scouring of the riverbed due to altered flow patterns. Five listed species‐at‐risk (endangered or threatened) are found in the St. Clair River. The Canadian Fisheries Act not only mandates no net loss of fish habitat, but also does not allow any disturbance or impairment of habitats deemed critical to species‐at‐risk. The Northern Madtom is an extremely rare benthic catfish that has been found in the lower St. Clair River. Potential impacts to the Northern Madtom, including disturbance or impairment of critical habitat, will be a “show stopper” with respect to actions taken to restore Lake Michigan‐Huron water levels.
Environmental regulatory hurdles are significant. This will be a public multinational effort that will trigger multiple Environmental Impact Statements and Assessments on both sides of the Border and will require concurrence of the affected First Nations and Tribes. There are no mechanisms or governance structures in place to coordinate multinational environmental assessments and a lack of available environmental, habitat, and fisheries data for the St. Clair River will limit the ability of agencies to produce comprehensive environmental assessments within a reasonable time frame.
A sequential analysis of the steps involved comply with all regulations and permits suggests that it would take 25 to 35 years to implement and complete a one‐time permanent restoration project, and if that project were incrementally staged to minimize downstream environmental impacts, it would take 45 years to complete the project (summarized in Brown 2011). Given the long lead time necessary to complete the project, the effects of Glacial Isostatic Adjustment (GIA) will have to be factored into the long‐term benefit analyses. 2
International Upper Great Lakes Study
St. Clair River Ecosystem Summary White Paper and Report Evaluation of Potential Ecological Impacts Resulting from Lake Michigan‐Huron Water Level Restoration and the Placement of Structures in the St. Clair River
Overview and Objectives Changes in the conveyance of the connecting channels from Lakes Michigan‐Huron to Lake Erie have occurred over the past 150 years due to various reasons including channel modifications and navigation dredging. In August 2010, the International Joint Commission sent a letter of guidance to the IUGLS Study Board asking them to explore the feasibility and implications of the following water‐level restoration scenarios: 1. 0 cm scenario – status quo, no restorative action; 2. 10 cm scenario – increases in conveyance since 1963; 3. 25 cm scenario – cumulative increases in conveyance that includes the 1960‐62 channel deepening; 4. 40 cm scenario ‐ cumulative increases in conveyance since 1906 through today, including 1933 to 1937 construction of the navigation channel; and a 5. 50 cm scenario – cumulative increases in conveyance from 1855 to the present. In response to this request, the Study Board has initiated an exploratory investigation of the upstream and downstream environmental effects of restoring water levels in Lakes Michigan and Huron. Various restoration options will be explored, including the types of structures that might be required to achieve these restoration goals. The purpose of this exploratory evaluation is to develop an understanding of the potential ecological impacts and issues associated with the placement of new structures in the St. Clair River to meet the desired water level restoration objectives. As part of this exploratory evaluation, a comprehensive literature review of data and information on the St. Clair River was undertaken and summarized in a draft St. Clair River white paper. To compliment this effort, an Experts Workshop was held in early February 2011 to identify and evaluate important environmental and regulatory issues associated with the placement of water control structures on the bed of the St. Clair River to restore Lake Michigan‐Huron water levels to a desired state. The workshop was designed to engage relevant agency people and NGOs, including interested members of the IUGLS, the IJC, and Public Interest Advisory Group (PIAG) liaisons. The objectives of the workshop were to: 1. Share initial ideas and concepts with technical stakeholders as to how and where this might be done; 2. Receive input from technical stakeholders as to existing environmental datasets, reports, publications, information, and concerns/issues related to placement and impacts of proposed structures; and to 3. Review applicable legal and regulatory framework with respect to the environment. This report represents a synthesis and summary of the draft St. Clair River white paper and results from the St. Clair River Ecosystem workshop. The findings of this report are summarized in the Executive Summary and in the Summary and Conclusions at the end of this report. 3
Proposed Action Scenarios In response to the request by the IJC to perform a preliminary evaluation of possible mitigation measures to compensate for increased conveyance in the St. Clair River, a review of past studies, reports, and publications was undertaken to summarize and build upon previous work. A final report was completed in November 2010 and submitted to the IUGLS (Bruxer and Carlson 2010). Additional work based on existing engineering design plans from prior studies was undertaken to examine the engineering design criteria to construct submerged sills on the bed of the Upper St. Clair River and other types of structures adjacent to Stag and Fawn Islands to permanently retard St. Clair River flows and gradually raise the water level of Lakes Michigan‐Huron. Several areas were identified based on past work as possible placement sites for these permanent restoration structures. The first site is located at the headwaters of the St. Clair River near the Bluewater Bridge (Bruxer 2010a). At his location, multiple submerged sills would be placed perpendicular to flow on the bed of the St. Clair River to permanently retard flows and raise the water level of Lakes Michigan‐ Huron (Figure 1). Various combinations of sills (both number and size) would be used to permanently increase Lake Michigan‐Huron water levels to a desired elevation. The second site also located at the headwaters of the St. Clair River where two large parallel dikes (or weirs) would extend into Lake Huron. The third and fourth sites are located in the St. Clair River east of Stag and Fawn Islands (Bruxer 2010b). At least three structures would be placed at each of these sites. Two structures parallel to the main channel axis would be located at the north and south ends of Stag and Fawn Islands, and a third rock‐filled structure oriented perpendicular to flow would be constructed in the side channels east of Stag and Fawn Islands (Figure 1). These structures would be designed to obstruct, not retard flow. As an alternative to a permanent restoration of Lake Michigan‐Huron water levels, adjustable inflatable flap gates could be installed across the eastern side channels at the Stag and Fawn Island sites. These adjustable flap gates would be designed and operated to regulate flows in the St. Clair River, i.e. restore (raise) water levels during low water periods but not increase water levels during high water periods. These structures would have the advantage of allowing ice to pass over them during the winter months thereby reducing the potential for ice jams in the river. Other methods that were considered included: 1) Installation of in‐stream turbines that would generate electricity from velocity of the river current. A preliminary analysis of this approach indicates that the placement of turbines would have a minimal effect on flow and only a small change in Lake Michigan‐Huron water levels (a few centimeters) 2) Placement of cobbles, rocks, and boulders or other features on the bed of the River to increase bed roughness and resistance to flow. Simple calculations show that an increase in the Manning’s “n” of 0.01 throughout the St. Clair River would increase Lake Michigan‐Huron water levels by up to 65 to 70 cm. Even though armoring of the entire river bed is probably not feasible due to cost and potential impacts to navigation, partial armoring of the river bed may provide an appropriate increase in roughness while providing potential improvements in aquatic habitat as well. The bed armoring approach has not been considered in the past, and additional modelling work and studies would be required to explore potential benefits, impacts, and feasibility of this approach (e.g. hydraulic, erosion and sediment transport, geotechnical, habitat, and navigation). 4
1
3
Lake Huron Headwaters 2
Bluewater Bridge
1 Bluewater Bridge
Stag Island 3 Stag Island
4 Fawn Island
2
4 Headwaters Fawn Island
Lake St. Clair
Figure 1. (1) Location of proposed sills at the headwaters of the Upper St. Clair River. (2) Location of proposed headwater structures in Lake Huron. (3) Location of proposed structures at Stag Island. (4) Location of proposed structures at Fawn Island. Varying combinations of sills (both number and size) could be used to permanently increase Lake Michigan‐Huron waters to a design elevation [(1) Bruxer 2010a, modified from Franco and Glover 1972; (3 & 4) Bruxer 2010b, adapted from Moore 1933].
Impact of these Actions on Water Levels and Flows Simple routing models have been run comparing flows and water levels for a one‐time “instantaneous” implementation and a “staged” implementation. A one‐time implementation represents a condition where the structures are installed and completed over a short period of time. The downstream impacts would become apparent quickly and the duration of those impacts would be a determined by the infill rate of Lake Michigan‐Huron until the design water level elevation is reached. A staged implementation represents a condition where the structures are installed and completed over an extended period of time (e.g. say 20 to 25 years), thereby minimizing potential detrimental impacts while Lake Michigan‐Huron water levels gradually equilibrate. An example comparison of the two approaches is illustrated for a 25 cm restoration scenario in Figure 2. These comparisons show that staged implementation reduces short‐term perturbations to downstream flows and water levels thereby minimizing potential environmental impacts. As engineering and design specifications have not been determined, it is possible that different combinations of structures may have different downstream impacts. Additional detailed hydraulic modelling will be required to perform a more comprehensive assessment of potential downstream impacts. 5
Figure 2. Comparison of one‐time vs staged restoration of Lake Michigan‐Huron water levels for 25 cm scenario. Staged restoration scenario is implemented over a 20 to 25 year period, 5 cm per every 5 years. 6
Environmental Overview It is anticipated that there will be environmental impacts to the St. Clair River, Lake St. Clair, and the Detroit River associated with each of these restoration scenarios. Broader ecological impacts to the Lake Michigan‐Huron and Lake Erie ecosystems may also occur, but will be evaluated separately using the IERM2 and SVM models currently under development by the IUGLS Ecosystems Technical Working Group (ETWG) and the Plan Formulation and Evaluation Group (PFEG). The Lake Huron ‐ Lake Erie Corridor system (HEC) consists of the waters and adjacent lands encompassed by the St. Clair River, the St. Clair Delta, Lake St. Clair, and the Detroit River (Figure 3 inset). This region contains a diverse range of aquatic habitats associated with coastal wetland, riverine, deltaic, and shallow nearshore and open‐lake environments including critical spawning, nursery, and forage habitats for multiple fish species and other aquatic organisms.
Figure 3. Location map of the St. Clair River Area of Interest.
Natural lands and waters within the HEC are particularly at risk to degradation as a consequence of both terrestrial and aquatic stressors. Urban and agricultural pressures have resulted in loss of over 90% of the riparian habitat bordering the HEC (Manny 2003). The HEC system is highly responsive to changes in water level regime given the shallowness of aquatic habitats and susceptibility of those habitats to inundation or loss through flooding or dewatering as a consequence of changes in flow and water level regimes. Connecting channel flows are driven primarily by climatic factors (mainly precipitation and evaporation in the upper Great Lakes) and are affected by anthropogenic channel modifications within the connecting channels. Within the HEC, increasing development pressures and urbanization have greatly altered these habitats, especially shoreline and adjacent nearshore areas (Manny, 2003; Nodwell et al. 2007). Armoring of the coastlines and adjacent banks of connecting channels has isolated and destroyed critical wetland habitat and continued watershed development has altered the timing and intensity of the run‐off patterns. Dredging of the connecting channels for commercial navigation has altered water depth, flow, substrate distributions, and habitat structure within the connecting channels and the St. Clair Delta, and has a long‐ 7
term effect on annual upper Great Lakes water levels as well (e.g. Quinn 1985; Derecki 1985; IUGLS 2009; Bruxer and Carlson 2010). The establishment of invasive species such as zebra mussels (Dreissena polymorpha) and round gobies (Neogobius melanostomus) has altered water clarity and changed food web dynamics within these systems (e.g., Vanderploeg et al., 2002). In particular, emergent and submergent aquatic macrophytes have flourished and have altered nearshore and shallow‐water habitats in Lake St. Clair over the past two decades. Invasive plant species such as phragmites (Phragmites Australis) and purple loosestrife (Lythrum salicaria) have replaced many native wetland plant species in the St. Clair Delta and create monotypic stands of dense reeds (up to 200 stems/m3) that significantly reduce plant and habitat diversity and wetland function. The expansion of invasive plant species is facilitated by extreme changes in water level regime, and is of special concern during periods of extended low water in the St. Clair system.
Lake St. Clair and St. Clair River Fishery This HEC system is highly productive and in 2001, based on comprehensive creel surveys, accounted for 34% of Michigan’s sport fish harvest and 43% of Michigan’s total Great Lakes fishing effort (G. Towns, MDNRE Fisheries Division). In 2001, approximately 23 hours of fishing effort per acre were expended within the HEC, which is 4 to 5 times higher than any of the five Great Lakes (Figure 4). A total of 61 fish species are listed for the Saint Clair River out of a total of 80 species listed for the entire Huron‐Erie Corridor. Of these, 30 species are considered to be dominant, very abundant, abundant or common for the Saint Clair River. These species include recreationally and commercially important species as well as special concern species, including those that are endangered or threatened. The Saint Clair River fish community includes resident and migratory cool water species (e.g. walleye, lake sturgeon, smallmouth bass, muskellunge, yellow perch, smelt, emerald shiner). The Saint Clair River seasonally supports migratory cold water species such as Chinook salmon, rainbow trout, Coho salmon, Atlantic salmon, lake whitefish, lake trout, and burbot). The sport fishery on Lake St. Clair is substantial, supporting one of the most valuable recreational fisheries in the world for walleye, yellow perch, smallmouth bass, and muskellunge (Figure 5). Thirty‐ three percent of all fish and 48 percent of all sport fish caught in the Great Lakes are caught in Lake St. Clair. The current (2004) estimated direct value of the recreational fishery for Michigan and Ontario waters combined is likely in excess of $30 million per year (USACE 2004). Moreover, recreational boating within the HEC is estimated to contribute more that $249 million per year to the economy of Michigan and Ontario. Sport fishing is a major contributor toward recreational boating activity. However, due to difficulties working in a deep navigation channel with steep bottom contours, strong currents, turbulence, and vessel traffic; long‐term fish monitoring and habitat data are sparse and most of the available fish data are derived from short‐term studies focused in nearshore shallow‐water areas of the River. Collection methods range from the use of electrofishing gear, seines, small trap nets, fyke nets, and small trawls. Creel surveys are also performed periodically to assess the St. Clair River fishery. Because of extensive modifications to the St. Clair River channel, most of the natural channel structure and associated habitat has been altered and removed from the system to create a trapezoidal channel suitable for navigation. Coupled with these navigation “improvements”, is the extensive shoreline hardening and modification of natural shoreline features that have eliminated shallow water bank‐edge habitats that are critical to many fish species and aquatic organisms. In fact, the few habitat surveys that have been done reveal limited habitat diversity and a paucity of suitable spawning habitats within most of the St. Clair River. 8
Figure 4. Angling effort per acre for Michigan waters of the Great Lakes.
Figure 5. Distribution of fish species sought by boat anglers in the Saint Clair River. Walleye is the primary target of the boat anglers on the Saint Clair River. However, good habitats are found in the interdistributary channels of the St. Clair Delta (e.g. North Channel near Algoma) and downstream from the Bluewater Bridge near the headwaters of the St. Clair River. These areas serve as important spawning sites for Lake Sturgeon (Acipenser fulvescens) which are a threatened species in the U.S. and Canada. The area of lake sturgeon spawning habitat downstream of the Bluewater Bridge is estimated to be ~160,000 m2 (52% of the St. Clair channel bottom at that site) and is considered to be one of the most important lake sturgeon spawning sites in the Great Lakes (Mike Thomas, MDNRE, personal communication). At this site, lake sturgeon are spawning on clean boulders, cobble, and gravel substrates associated with strong currents (high flows) in upper reaches of 9
the St. Clair River. Further downstream in the lower reaches of the St. Clair River, another more lake sturgeon spawning site (~2,500 m2) has been identified near Algonac, Michigan. Tagging studies demonstrate that the St. Clair River serves as an important fish migration route during lake sturgeon spawning runs, i.e. “Recaptures of lake sturgeon tagged in the St. Clair River and Lake St. Clair indicated that fish moved between the St. Clair River and lakes Huron and Erie. In some cases these movements may represent spawning migrations of adult Lake Huron or Erie fish to and from natal spawning sites in the St. Clair River.” (Thomas and Haas 2004). They also state that “The St. Clair River telemetry study (Boase 2003) found that nearly 70% (11/16) of sturgeon implanted near the North Channel spawning site during spawning season subsequently migrated downstream into Lake St. Clair for the summer. An upstream migration by some fish towards, and presumably into, Lake Huron was also apparent.” This not only highlights the importance of the connecting channels and Lake St. Clair as critical spawning habitat, but also as an important fish migration route that connects Lake Huron and Lake Erie.
Distribution of Walleye Tagged in Lake Erie 2000-2009
N
W
E
S
Lake St. Clair
Source: Robert Haas MDNRE
Figure 6. Distribution of Walleye tagged in Lake Erie between 2000‐2009 recovered within the HEC. These data clearly show fish using the connecting channels as a migration route from Lake Erie into Lake St. Clair and into Lake Huron (Bob Haas, personal communication). Walleye tracking studies also document significant movement of fish through the connecting channels. Lake St. Clair, and Lake Huron (Figure 6). Similar studies of the movements of Chinook salmon also show use of the connecting channels and Lake St. Clair as a migratory route from Lake Michigan‐Huron into Lake Erie. These, and other studies clearly show that disruption of natural migration routes and/or loss of connectivity (or access) to spawning and nursery habitats by water control structures placed within the St. Clair River would cause significant damage to the Great Lakes Fishery.
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St. Clair River Species at Risk Table 1 lists eight species‐at‐risk found in the Huron‐Erie Corridor and the status of those species in Michigan and Ontario. The species highlighted in green are present in the St. Clair River. Of particular note are the Lake Sturgeon (threatened) and the extremely rare Northern Madtom (endangered). Unfortunately, habitat usage by several of these species‐at‐risk is unknown not well understood. Ongoing studies in the St. Clair River by Fisheries Oceans Canada (Dr. Nicholas Mandrak) are designed to address questions about habitat usage and the distribution of these species‐at‐risk in the St. Clair River. These ongoing studies are important because in addition to mandating no net loss of fish habitat, the Canadian Fisheries Act is very strict with regard to actions that impair or destroy habitat that is used species‐at‐risk. Disturbance or impairment of those habitats is not allowed under the Canadian Fisheries Act and could significantly impact the ability of the IJC (or other agencies) to implement measures designed to restore Lake Michigan‐Huron water levels by placing structures in the St. Clair River.
Species River Darter Channel Darter Eastern Sand Darter Mooneye Lake Sturgeon Northern Madtom Pugnose Shiner Pugnose Minnow
Table 1. Huron Erie Corridor Species‐at‐Risk Michigan Status Ontario Status Endangered Endangered Threatened Threatened Threatened Endangered Endangered Endangered
Not at Risk Threatened Endangered Not Assessed Threatened Endangered Endangered Special Concern
Figure 7. The Northern Madtom is an extremely rare benthic catfish found in the lower reaches of the St. Clair River. Ongoing habitat studies are focused on habitat usage and distribution of species‐at‐risk within the River. Potential downstream impacts to Northern Madtom habitat may limit the types of proposed water level remediation projects in the St. Clair River. 11
Water Level Restoration ‐ Fishery and Species‐at‐Risk Issues The sites selected for placement of water control structures at the headwaters of the St. Clair River (locations 1 and 2) appear to be coincident with critically important lake sturgeon spawning habitats in the St. Clair River and perhaps the Great Lakes (Figure 8). The impact of placing water control structures over lake sturgeon spawning habitat is unknown, but is anticipated to be negative. It is possible to incorporate habitat enhancements into the design of the structures, but it is not likely that those enhancements would adequately mitigate for the loss of natural spawning habitat at these sites. Given that lake sturgeon are currently listed in both the U.S. and Canada as endangered species, it is unlikely that approvals would be received to modify or disturb existing natural lake sturgeon spawning habitat.
Figure 8. Upper image ‐ comparison of known lake sturgeon spawning habitat with proposed structures at headwaters of the St. Clair River. Lower image – comparison of potential habitat restoration sites identified by USGS with proposed structures at Stag Island site. 12
The USGS, working with other partners in the HEC, has successfully restored Lake Sturgeon spawning habitat in the Detroit River and is currently working on a project funded by Great Lakes Restoration Initiative (GLRI) to identify potential fish habitat restoration sites within the St. Clair River. In addition to shoreline and bank‐edge habitats, discussions with the USGS indicate that the northern edge of Stag and Faun Islands have been identified as potential lake sturgeon spawning habitat restoration sites which may benefit other species as well (David Bennion, USGS, personal communication – see lower image Figure 8). The placement of water control structures at these locations may, or may not, present an opportunity for fish habitat restoration at those sites. In Canada, the Fisheries Act specifies no net loss of fish habitat, so developing habitat‐friendly designs would be beneficial. Finally, the Lake Committees of the Great Lakes Fishery Commission identify Fish Community Goals and Objectives (FCGOs) to guide management strategies for each of the Great Lakes. FCGOs have been drafted for the Huron‐Erie Corridor and connecting channels, but are currently undergoing an internal review before being released to the public. In general, all of the Great Lakes FCGOs list restoration of native species as a major management priority within the Great Lakes. This effort also includes the protection and restoration of critical spawning and nursery habitat for those native species. Projects that are designed to rehabilitate and restore native fish habitats in support of the FCGOs would likely be well‐received and supported by Great Lakes fishery resource managers and anglers.
Contaminant Distribution, Resuspension and Bioaccumulation Potential Point source contaminants have historically impacted the St. Clair River, particularly along the Canadian shoreline (SCRBPAC 2001; USACE 2004; ENVIRON 2009). Much of the shoreline was designated as degraded or impaired based on benthic community studies and high levels of sediment contamination. With the passage of time, historic contamination sites have been remediated either through elimination of point sources, contaminant removal (dredging), and/or isolation by encapsulation (capping). Between 2002 and 2004, 13,370 cubic metres of contaminated sediment adjacent to the Dow property was remediated through hydraulic dredging and removed for disposal (at a cost of $18M USD), such that downstream of this site, only an 8.3 km reach of the St. Clair River required further evaluation. An ecosystem approach to sediment assessment was used to evaluate the potential effects of contaminants on sediment‐dwelling and aquatic organisms, as well as the potential for contamination to biomagnify in the food chain (ENVIRON, 2009). Biomagnification refers to the process in which chemical levels in plants or animals increase from transfer through the food web (e.g., predators have greater concentrations of a particular chemical than their prey). Sediment concentrations of the industrial discharges, hexachlorobenzene and hexachlorobutadiene, were found to be below clean‐up targets of 0.22 mg/kg and 3.5 mg/kg, respectively, set by Kauss, et al (2001). Sediment concentrations of octachlorostyrene, a byproduct of the chlorination of organic chemicals, were observed to be below an equilibrium partitioning benchmark of 650 mg/kg which is considered protective of benthic invertebrates, aquatic organisms that live on or in sediment (Di Toro, et al, 1991). Although 61% of the surficial (top 0 to 15 cm) sediment samples were greater than the provincial mercury (Hg) Sediment Quality Guideline Severe Effects Levels (2 mg/kg), there was no strong evidence of benthic invertebrate toxicity or benthic community structure changes attributable to Hg contamination. However, prioritized areas for sediment management based on risks from Hg to local sport fish (high risks for northern pike and redhorse sucker, and intermediate risks for carp, freshwater drum, white sucker and yellow perch) have been identified and mapped (ENVIRON 2009; see Figure 9). 13
Figure 9. Priority Areas for sediment management (ENVIRON, 2009) Sediment Management options are currently being assessed for Priority Areas 1, 2 and 3: • dredging (hydraulic and/or mechanical) with the application of a thin layer (15 to 20 cm) of clean sand/gravel to cover residual/remaining contaminated sediment; • isolation capping (without prior dredging) of 40 to 60 cm layer of clean sand/gravel; • monitored natural recovery (natural capping by silt flowing downstream; periodic monitoring to make certain deeper sediment contaminants continue to be buried and undisturbed). The placement of proposed structures at the Stag Island site may be problematic given that the locations identified are closely associated with high priority contaminated sites and areas of possible concern with respect to sediment resuspension. If contaminated sediment is left in place in Priority Area 14
3, structure construction plans must take into consideration the fact that sediment at depth (i.e. buried sediment) was found to be up to five times higher than surface sediment in some places. Hydrodynamic effects of the structures on Hg‐contaminated sediment in Priority Area 3 would depend upon the magnitude, location and design of the structures (Figure 10). Additional elevated risk for resuspension is associated with the ferry crossing downstream of Priority Area 3 (Figure 11, Reach 4b), adjacent to the central part of Stag Island, and must also be considered. Turbulence or changes in river flow patterns due to construction of the proposed structures could cause re‐suspension of contaminated sediment. The structures could also affect sedimentation rates, which would be a concern should Monitored Natural Recovery be the preferred option chosen for Priority Area 3.
Figure 10. Location of Priority Area 3 in relation to proposed upstream extension of Stag Island. Furthermore, in anoxic environments, Hg is converted in sediment to methyl mercury. Methyl mercury is the biologically available form of the chemical. Detailed sampling revealed a reach of the river where there is elevated methylation risk adjacent to the northern tip of Stag Island (Figure 11, Reach 4a). Methylation in this reach is related to the presence of elevated sediment mercury concentrations and the potential for organic enrichment from existing sewer structures. Downstream impacts of potential actions that may disturb and/or resuspend contaminants will have to be carefully considered as part of any environmental assessment within these waters and it would be necessary to conduct hydrodynamic modeling in order to determine the safety envelope for this site. 15
Figure 11. Areas identified with high sediment redistribution and/or elevated methylation risk in the St. Clair River (ENVIRON 2009). Note that Priority Area 3 is referred to as "Reach 3B" in this figure.
Environmental Laws and Regulations The St. Clair River and the St. Clair Delta are international waterways ‐ portions of which are located in Canada, the United States, and the Walpole First Nation. These waters are subject to the treaties, laws, and regulations promulgated by these respective entities. The international nature of the St. Clair River will require that proposed actions be implemented under a joint agreement between parties, and that appropriate environmental laws and regulations be satisfied. The project will be subject to provisions of the Boundary Waters Treaty of 1909. Based on discussions during the workshop, it became clear that legal requirements will depend on the size and significance of the proposed project and who is implementing the project. For a public project of this magnitude, environmental permits will be required and issuance of those permits will likely require an Environmental Impact Statement (U.S.) and an Environmental Assessment (Canada). Permits from the Michigan Department of Natural Resources and the Environment and a Provincial Environmental Assessment will also be required. Consultation will also have to occur with the First Nations and Tribes to obtain concurrence and ensure that their interests are represented in the proposed project as well In Canada, the Constitution Act 1882 supersedes all legislation and legislative outcomes. The Act requires mandatory meaningful consultation with the First Nations. The proposed actions will require approval of the International Joint Commission and by several Canadian Federal Ministers. Under the Canadian Fisheries Act, approvals will be required from of the Federal Ministry of Fisheries and Oceans and the Federal Ministry of Transportation because it is located within a Canadian navigable waterway. 16
In the United States, various sections of U.S. law may apply, such as Section 404 of the U.S. Clean Water Act (disposition of dredge and fill material); National Environmental Policy Act; Fish and Wildlife Coordination Act (USFWS and State Agencies); Section 7 of the Endangered Species Act; Section 9 of the Endangered Species Act (taking of a listed species); and the Migratory Bird Treaty Act. Moreover, in U.S. waters, bottomlands are not considered to be public lands and are held by adjacent riparian owners. In Canada the Ontario Ministry of Natural Resources manages Provincial Crown Land and public projects on Crown Lands require both Federal and Provincial Environmental Assessments. In a white paper prepared as part of an institutional/governance analysis for the IUGLS, Brown (2011) summarized applicable environmental laws and regulatory requirements for both the U.S. and Canadian portions of the St. Clair River. “In the U.S. the project would come under the authority of the National Environmental Policy Act, (NEPA). This Act is administered by the U.S. Environmental Protection Agency (EPA), however under NEPA, channel projects are administered through the U.S. Army Corps of Engineers, (USACE). The USACE would also administer approvals needed under the Rivers and Harbors Act. Other approvals would be required under the Endangered Species Act; the Migratory Bird Treaty Act; and, the Fish and Wildlife Coordination Act, (all administered by U.S. Fish and Wildlife Service), and the Clean Water Act, (administered by the EPA). In Michigan, a permit would be required under the Michigan Natural Resources and Environmental Protection Act (Part 301 Inland Lakes and Streams). This is administered by the Michigan Department of Natural Resources and Environment (MDNRE). The MDNRE also administers the federal permit program which regulates the dredging or filling of inland lakes and streams under Section 404 of the Clean Water Act except in coastal areas where the United States Army Corps of Engineers retains this authority. The U.S. regulatory process would require the preparation of an Environmental Impact Statement, (EIS), and an environmental assessment. In Canada, the project would come under the federal Canadian Environment Assessment Act as it would trigger the process with potential fisheries impacts under Section 352 of the Fisheries Act. Given the significant impact of the project on Great Lakes levels and on the St. Clair River channel in the area of construction, it is likely that the project would require a detailed environmental review involving comprehensive studies (required for projects altering a waterway – Section 28 Canadian Environmental Assessment Act), or possibly a review panel. The EA process would be lead by the Canadian Environmental Assessment Agency and would involve the participation of other federal regulatory agencies such as Transport Canada, (Navigable Waters Protection Act), Fisheries and Oceans, (Fisheries Act), and Department of Foreign Affairs and International Trade (Boundary Waters Treaty Act). In Ontario, the provincial environmental assessment process is through the Ontario Environmental Assessment Act administered by the Ontario Ministry of Environment and applies to all provincial ministries and agencies and to municipalities. Compensation works in the St. Clair River would require a Class EA under the Lakes and River Improvement Act, (administered by the Ontario Ministry of Natural Resources), as the project would alter the bed of the St. Clair River. Approvals may also be required under the Public Lands Act, (administered by OMNR), and the Environmental Protection Act, (administered by the Ontario Ministry of Environment). Local government approval would also be required if the project was constructed on the Canadian shore or channel bed. Alterations to the channel bed or floodplain would come under the authority of the St. Clair Region Conservation Authority’s Flood and Fill Regulations (Conservation Authority Act). Any works on the shore would have to comply with municipal zoning by‐laws. 17
Coordination between federal and provincial environmental assessments is through the Canadian Environmental Assessment Agency. There is presently no formal agreement between Canada and the U.S. for the coordination of environmental assessments.”
Table 2. Regulatory and Environmental Assessment Requirements US Federal Acts Canadian Federal Acts National Environmental Policy Act (administered by USACE for channel projects) Rivers and Harbors Act (administered by USACE) Endangered Species Act* Migratory Bird Treaty Act* Fish & Wildlife Coordination Act* (* administered by Fish &Wildlife Service) Clean Water Act (administered by EPA)
Canadian Environmental Assessment Act (administered by Environment Canada) Fisheries Act (administered by Fisheries Oceans Canada)
State of Michigan Natural Resources and Environmental Protection Act [EIS and EA required] (administered by Michigan Department of Natural Resources and Environment)
Province of Ontario Ontario Environmental Assessment Act** Ontario Environmental Protection Act** (** administered by Ministry of Environment) Lakes and Rivers Improvement Act*** Public Lands Act*** (*** administered by Ministry of Natural Resources)
Local Government No authority for in‐water projects
Local Government Flood and Fill Regulations under the Conservation Authorities Act (administered by the St. Clair Region Conservation Authority)
Riparian Owners Ownership extends to the river bed and includes bottomlands
Aboriginal Rights Walpole Island First Nation has a claim on the bed of the St. Clair River Aamjiwnaang First Nation (Sarnia)
Source: Brown (2011) As discussed previously, placement of these structures may occur over time (staged implementation) in order to minimize downstream impacts due to changes in flow regime and/or water levels. A long‐term water level project in the St. Clair River may be subject to changing environmental laws and regulations. It is unclear as to how this type of long‐term project would be implemented, and what impact changing environmental laws and regulations would have on the project. Moreover, based on past experience, it may take a considerable period of time (years) to complete the environmental assessments and meet the regulatory requirements necessary for construction to begin. Table 3 provides an estimated timeline to complete a project that began in 2012 (Brown 2011, Appendix B). For a one‐time permanent project (not a staged project), it would take a minimum of 25 years to 18
complete. If the permanent project were staged over a 20 year period to minimize ecological and environmental impacts, it would take a total of 45 years to complete the project. For an adjustable structure designed to manage water levels, it would take a minimum of 35 years to complete the project. Note that a staged installation for an adjustable structure would not be necessary.
Table 3. Estimated Time to Implement a Permanent Structure vs. an Adjustable Structure
Source: Brown (2011) Appendix B 19
St. Clair Delta Key environmental variables and processes that define habitat within the deltaic zone include elevation/topography/bathymetry (water depth), water velocity and temperature, dissolved oxygen, water clarity, total suspended solids (quantity and quality), and substrate composition and distribution. The processes that create and maintain the delta are a combination of strong unidirectional flows and the transport and deposition of sediments within the St. Clair delta complex. A continuous supply of both coarse and fine‐grained sediment to the delta system is necessary to offset the effects of dewatering, compaction, and continued erosion. Without this sediment supply, low‐lying areas of the delta will gradually disappear, altering the distribution and pattern of critical fish and aquatic habitats. Both riverine and lake processes affect deltaic environments and variations in Lake St. Clair flows and water levels will control which (and where those) processes are dominant. Habitats within the main distributary channels will generally be less sensitive to Lake St. Clair water level fluctuations due to the dominance of unidirectional riverine flows. Habitats associated with shallow low‐relief interdistributary bays and adjacent riparian/deltaic wetland, crevasse splay, and backwater sub‐environments will be particularly sensitive to Lake St. Clair water‐level fluctuations. The distribution of aquatic macrophytes and contaminants are also important environmental factors. Key inputs are source‐water flows from Lake Huron, distributary flows and loadings, and contaminant loadings from point and non‐point sources upstream from the delta. Thus actions taken upstream that affect flows and water levels will have direct impact on the St. Clair Delta and associated interdistributary channels and will need to be assessed. These environmental variables are dynamic, with boundaries and interactions that are driven by both riverine and lake processes that often involve climatic/seasonal cycles that influence nutrient and contaminant loadings, hydrology, erosion and deposition, thermal characteristics, and connectivity. Habitat utilization within the St. Clair Delta may also be limited by a loss of connectivity and increase in fragmentation during extended periods of low water levels. This loss of connectivity is exacerbated by the filling of low‐lying riparian and deltaic wetlands, shoreline hardening, and the construction of dykes and levees along the distributary channels.
Lake St. Clair Lake St. Clair is a relatively shallow lake with a gently sloping bottom and water depths averaging 3 to 5 m, with the exception of the dredged navigation channel. Environmental sub‐zones (aquatic) within Lake St. Clair include: coastal margin and delta margin areas dominated by high‐energy coastal processes (water depths generally less than 1 m), a large semi‐protected embayment (Anchor Bay) and shallow‐water open lake areas dominated by lower energy open‐lake processes (water depths 1 to 5 m), and deep‐water distributary mouth and navigation channels (water depths ~10 m). The circulation of Lake St. Clair is largely dominated by the flows from the St. Clair River to the Detroit River. The average river discharge is about 5,700 m3/s. High flows and shallow water depths produce a delicate dynamic balance between hydraulically‐driven and wind‐driven circulation patterns within the lake. Waves are typically small in amplitude due to the lake’s relatively limited fetch length, shallow water, and gentle offshore slopes. Consequently, the waves tend to break offshore and produce relatively minor littoral flows, especially in the area of the St. Clair Delta.
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Leach, 1980 Limnological sampling intensity in Lake St. Clair in Relation to Distribution of Water Masses Two distinct water masses denoted A & B 1. Mass A composed mostly of low nutrient water from Lake Huron. 2. Mass B more stable water enriched by nutrient loadings from tributaries and urban development.
Lake St. Clair
1978
A
B
1990 & 1994 taken from R.W, Griffiths: “Unpublished maps of aquatic plants in Lake St. Clair” Ontario Ministry of Environment and Energy. Figure 9. Water mass “A” (left above) is dominated by cool oligotrophic Lake Huron waters characterized by low nutrient levels and short residence time. Water mass “B” is dominated by warmer waters with higher nutrient levels and longer residence times. Macrophyte distribution in 1994 is more representative of historic conditions (right above). MDNR estimates 80% of the Lake St. Clair Lakebed is colonized by aquatic macrophytes. (Source: Robert Haas, MDNR, personal communication) Within the shallow‐water open lake zone, there are at least two major water masses that behave in ways analogous to larger open lake systems (Figure 9). Water temperatures in Lake St. Clair are strongly influenced by shallow water depths and the cooler waters of Lake Huron conveyed by the St. Clair River, its primary contributing source. Temperatures change quickly, responding to changes in seasonal atmospheric temperature. Water is well mixed, so that temperatures are usually similar at the surface and at the bottom. The thermal influence of Lake Huron is most obvious in the western half of the lake, where Lake Huron water is discharged through the north and middle St. Clair River channels into Lake St. Clair, producing summer water temperatures about 2 to 4°C lower than occur in the eastern half of the lake (Bolsenga and Herdendorf 1993). Work by the MDNRE and others have shown that up to 80% of the bed of Lake St. Clair has been colonized by aquatic macrophytes (Haas et al. 2005). The combination of relatively shallow water depths, energy, extensive beds of submergent aquatics, and distinct water‐mass characteristics create a unique and highly productive mosaic of aquatic habitats within Lake St. Clair. Because Lake St. Clair is so shallow, changes in upstream flows and water levels can adversely impact the Lake St. Clair ecosystem. A lowering of Lake St. Clair water levels by a meter or more could eliminate more than 40% of the available fish spawning habitat in shallow nearshore areas of Lake St. 21
Clair. Given the relative importance of the Lake St. Clair fishery, significant reductions in water level for a period of 3 years or longer could have a catastrophic effect on the Lake St. Clair fishery (ETWG Lake St. Clair Ecological Performance Indicator, 2010).
Summary
Key St. Clair River Environmental Findings •
Critical fish habitat for endangered species located at headwaters of the St. Clair River near the Bluewater Bridge (critically important lake sturgeon habitat)
•
Potential fish habitat restoration sites are located adjacent to Stag and Fawn Islands
•
St. Clair River is an important fish migratory pathway between Lake Erie and Lakes Michigan‐Huron
•
St. Clair River fishery is economically important, but available fish and habitat data are limited (no systematic monitoring or assessment programs)
•
Contaminants (mercury) are present in sediments along the Canadian (eastern) shoreline near Stag Island
•
Regulatory hurdles are significant and my take 25 to 35 years to implement a one‐time project and up to 45 years to implement a longer‐term staged project
Key Environmental Issues and Results •
•
•
Long‐term implementation (staging) of restoration project will minimize downstream environmental impacts resulting from altered St. Clair River flow regimes and water levels o
Hydraulic routing model run for a 25 cm scenario shows minimal changes to downstream flows and water levels when implemented over a 20 to 25 year period adjusting water levels 5 cm every 5 years, thereby significantly reducing potential downstream environmental impacts.
o
More detailed analyses including the use of hydraulic routing models will be required to assess downstream environmental impacts once the project design and implementation specifications are developed.
Locations of proposed water control structures overlay and are coincident with critical habitat areas in the St. Clair River o
Critical fish habitats for lake sturgeon (listed as endangered in both the U.S. and Canada) are found downstream from the Bluewater Bridge.
o
Possible habitat enhancements associated with water control structures would not effectively mitigate loss of natural lake sturgeon spawning habitat.
o
Possible alternative sites downstream from the mouth of Black Creek are too shallow to place water control structures without impacting navigation.
o
Stag and Fawn Island sites are coincident with potential habitat restoration sites identified by the USGS in a GLRI‐funded study.
Alternatives to proposed water control structures o
Increase bed roughness (Manning’s “n”) by placing boulder cobble material on channel floor would retard flows and create new aquatic habitat. This approach was not considered in prior 22
studies and would require extensive hydraulic modeling and validation before being considered for implementation. •
St. Clair River is an important migratory pathway for aquatic organisms between Lakes Michigan‐ Huron and Lake Erie. o
•
•
Species at Risk (e.g. Northern Madtom) may be a “show stopper” in Canadian waters under the Canadian Fisheries Act. o
Potential for destruction or impairment of habitats used by species‐at‐risk (not permissible under Canadian Fisheries Act)
o
No habitat data available for Northern Madtom. Fisheries Oceans Canada conducting ongoing research in St. Clair River to determine Northern Madtom distribution and habitat utilization.
Concerns about possible disturbance or resuspension of contaminated sediments during construction activities and/or due to altered flows resulting from placement of water control structures within the side channel east of Stag Island. o
•
•
Regulatory structures that restrict movements of migratory fish would be detrimental to the Great Lakes fishery.
Implementing agency must design and assume responsibility for mitigation/cleanup of contaminated sediments that are disturbed by construction activities and/or altered flows resulting from placement of water control structures.
Environmental regulatory hurdles are significant. Estimate 25 to 35 years to complete one‐time restoration project. Estimate 45 years to complete a long‐term staged project o
Multinational issues related to coordination of environmental requirements and permitting
o
Lack of available environmental, habitat, and fisheries data will limit the ability of agencies to produce comprehensive environmental assessments within a reasonable time frame.
o
Additional regulatory details are summarized in White Paper #2 from the AM Institutional Analysis
Effects of GIA are an important consideration due to the long time frame needed to implement project. o
Example: GIA in the Georgian Bay area will negate any benefits derived from a 10 cm restoration of Lake Michigan‐Huron water levels by the time the project is fully implemented.
Conclusions Potential St. Clair River environmental issues are significant. A comparison of potential benefits versus environmental impacts of restoring Lake Michigan‐Huron water levels by placing water control structures on the bed of the St. Clair River will show that: •
Local environmental impacts will be severe,
•
Regulatory requirements are complex, and
•
Long time frame to implement project (35 to 45 years) will negate many of the anticipated benefits.
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