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Emergency Reduction of Lake Manitoba and Lake St. Martin Water Levels Aquatic Environment Monitoring January - August 2012 A Draft Report Prepared for Manitoba Infrastructure and Transportation By: North/South Consultants Inc. March 2013 Emergency Reduction of Lake Manitoba Aquatic Environment Monitoring and Lake St. Martin Water Levels January-August 2012 EXECUTIVE SUMMARY Due to widespread record flooding throughout southern Manitoba during 2011, water levels in Lake Manitoba and Lake St. Martin were several feet higher than desirable, resulting in significant damage to hundreds of properties, restricted road access to several communities, and long-term evacuation of four First Nations communities. As part of emergency relief measures, the Province of Manitoba, through Manitoba Infrastructure and Transportation (MIT), constructed an emergency channel (Reach 1 Emergency Outlet Channel) to increase water flow from Lake St. Martin to Lake Winnipeg. Reach 1 allows water to flow from Lake St. Martin through the Buffalo Creek Drainage System and into the lower Dauphin River, immediately upstream of Lake Winnipeg. Water began to flow along the diversion route on 01 November, 2011. Concurrent with construction and operation of Reach 1, MIT initiated environmental studies and monitoring to help describe and assess environmental effects arising from operation of Reach 1. A review of existing information pertinent to aquatic environments in Lake Manitoba, Fairford River, Lake St. Martin, Dauphin River and the Sturgeon Bay area of Lake Winnipeg was conducted and used to provide a preliminary assessment of project-related effects on affected water bodies in the area. During this process, data deficiencies were identified and a monitoring work plan was developed to: • Identify studies that would provide information to fill data gaps to better understand aquatic impacts and plan appropriate mitigation strategies; and, • Collect information to fill identified information deficiencies to provide a background against which post-project changes can be measured. Where possible, studies were designed to provide information to help assess aquatic impacts, as well as provide a baseline against which post-project changes could be measured. Field investigations were conducted through fall 2011 and results were presented in North/South Consultants Inc. (2013). The need for an additional drainage channel to protect the community of Dauphin River from anticipated flooding due to ice jamming at the river mouth during spring break up was identified in fall 2011. The second channel (Reach 3 Emergency Channel) was constructed through winter 2012, and was oriented to deflect flow from Reach 1 and Buffalo Creek to Sturgeon Bay, thereby reducing flow along the lower Dauphin River. At MIT’s request, a second work plan was developed to collect aquatic environment baseline information prior to operation of Reach 3, as well as to collect additional monitoring information related to operation and closure of Reach 1 and, once it became operational, Reach 3. At the time the work plan was prepared, it was anticipated that operation of Reach 1 and Reach 3 would cease at the end of August 2012. Thus, the second work plan included all necessary studies required to document potential operational and closure-related effects on affected water bodies. Emphasis of the studies was placed on water quality, sedimentation, and fish and fish habitat, and included the period extending from January i Emergency Reduction of Lake Manitoba Aquatic Environment Monitoring and Lake St. Martin Water Levels January-August 2012 to August, 2012 (the study period). This report provides results of field programs conducted during that time. While Reach 3 was constructed but not operated, operation of Reach 1 continued into November 2012, and monitoring associated with operation of the channel was continued through fall 2012. Data collections will be ongoing throughout the post-operational phase of Reach 1. Ultimately, the data presented in this report and collected subsequently will be used to produce an environmental effects assessment related to the operation of Reach 1. Results of monitoring information collected from January to August 2012 are presented in the following sections. Emphasis is placed on describing information collected during that period. Detailed examination of Reach 1 operational effects will be provided in subsequent reports, following collection of post-operational data. Water Quality Monitoring Water quality monitoring was conducted to document potential changes in water quality during operation of Reach 1, and to help determine the spatial extent over which any changes to water quality may have occurred. Water quality data were collected from upstream of Lake Manitoba and throughout Lake St. Martin, the Reach 1 Emergency Outlet Channel System, and Sturgeon Bay during operation of Reach 1. Water quality data collections consisted of several components, each with discrete objectives. Water quality monitoring consisted of the following programs: • Regional Water Quality Monitoring Program (RWQMP); • Operational EMP Monitoring; and, • In situ and TSS Monitoring in Sturgeon Bay. RWQMP During the conduct of the RWQMP, water quality information was collected from all major waterbodies and waterways within the study area that were affected by flooding and encompassed the major inputs to the north basin of Lake Manitoba (i.e., Waterhen River and at the Lake Manitoba Narrows) downstream to and including Sturgeon Bay on Lake Winnipeg. The objectives of the program were to: • monitor water quality conditions on a regional level during Reach 1 operation; • supplement data sets at sites within the study area where Manitoba Conservation and Water Stewardship, Water Quality Management Branch (MCWS) conducts water quality monitoring; and, • evaluate spatial differences in water quality within the study area. An assessment of potential effect(s) of the operation of Reach 1 on the water quality on potentially affected waterbodies has not been undertaken for this report. A brief assessment will be included with the presentation of the results from the fall 2012 monitoring program with a thorough assessment including historical and project-related water quality data to follow. ii Emergency Reduction of Lake Manitoba Aquatic Environment Monitoring and Lake St. Martin Water Levels January-August 2012 RWQMP results indicate that water quality within the study area can be generally described as moderately nutrient-rich, low to moderately turbid, slightly alkaline, hard to very hard, and well- oxygenated. Lake St. Martin was consistently isothermal and in situ parameters, including DO, turbidity, pH, and specific conductance were consistent across depth. Molar ratios of N:P indicated that the lake was phosphorus limited in 2012. All routine water quality variables for which there are MWQSOGs and CCME guidelines, including phosphorus, DO, pH, ammonia, nitrate and nitrite were within PAL objectives and guidelines. Buffalo Creek and the Dauphin River were also phosphorus limited and all routine water quality variables for which there are MWQSOGs and CCME PAL guidelines, including phosphorus, DO, pH, ammonia, nitrate and nitrite were within PAL objectives and guidelines. Sturgeon Bay was consistently isothermal and DO, turbidity, pH and specific conductance were fairly consistent across depth. Based on N:P molar ratios, the bay was phosphorus limited during all seasons. The water quality of Sturgeon Bay was influenced by the Dauphin River such that sites closest to the river mouth exhibited water quality similar to upstream sites, including: higher alkalinity; higher conductivity and TDS; higher total nitrogen; lower carbon concentrations and, higher chlorophyll a. This trend was particularly evident during the open-water season. The MWQSOGs narrative guideline for phosphorus in lakes was exceeded at the mouth of the Dauphin River during May and four sites in Sturgeon Bay during July. DO concentrations near the bottom were below the MWQSOGs for the protection of cold water aquatic life at the mouth of the river in July. Concentrations of the major ions (i.e., calcium, chloride, magnesium, potassium, sodium, and sulphate) tended to be higher at sites closer to the Dauphin River outflow than at the other sites sampled in Sturgeon Bay, reflecting the higher concentration of these substances at upstream waterbodies in the region relative to Lake Winnipeg. Aluminum, cadmium, chloride, fluoride, iron, selenium, and silver all exceeded PAL guidelines or objectives on at least one occasion within the study area. All other metals and major ions were within MWQSOGs and CCME guidelines for PAL. Of the 63 pesticides analysed for, only glyphosate and 2,4-D were detected in the study area; both were below the federal and provincial guidelines for PAL. Operational EMP Monitoring Operational EMP monitoring was conducted from January to Reach 1 closure in November 2012. The objective was to monitor potential changes to water quality in Buffalo Creek and the lower Dauphin River during operation of Reach 1, and was a continuation of Construction EMP monitoring conducted during fall 2011. Construction EMP monitoring indicated that TSS concentrations had returned to near baseline conditions following an initial increase measured in November 2011 (AECOM 2012). During the spring freshet in 2012, TSS concentrations increased at all sites, but particularly in Reach 1 and Buffalo Creek iii Emergency Reduction of Lake