Review of the Potential Effects on Selected Ecological and Cultural Resources of Proposed Changes in Water Level Regulations for Rainy and Namakan Lakes
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REVIEW OF THE POTENTIAL EFFECTS ON SELECTED ECOLOGICAL AND CULTURAL RESOURCES OF PROPOSED CHANGES IN WATER LEVEL REGULATIONS FOR RAINY AND NAMAKAN LAKES Prepared by Dennis Anderson Peter Fasbender Virginia Gnabasik St. Paul District U.S. Army Corps of Engineers 190 Fifth Street East St. Paul, Minnesota 55101-1638 January 1997 Table of Contents EXECUTIVE SUMMARY ........................................................................................................... iii 1.0 INTRODUCTION .....................................................................................................................1 1.1 Location .........................................................................................................................1 1.2 Background ....................................................................................................................1 1.3 Proposed Rule Curve Changes.......................................................................................2 1.4 Purpose of Review .........................................................................................................3 2.0 LITERATURE REVIEW PROCESS ........................................................................................4 3.0 EVALUATION..........................................................................................................................4 3.1 General ...........................................................................................................................4 3.2 Water Quality and Plankton ...........................................................................................5 3.2.1 Summary of Information on Water Quality and Plankton ..............................5 3.2.2 Effects Under the Current IJC Rule Curves on Water Quality and Plankton .5 3.2.3 Anticipated Effects Under the Proposed ISC Rule Curves on Water Quality and Plankton....................................................................................7 3.3 Benthic Macroinvertebrate Community Including Mussels ..........................................8 3.3.1 Summary of Information on Benthic Macroinvertebrates ..............................8 3.3.2 Effects Under the Current IJC Rule Curves on Benthic Macroinvertebrates .9 3.3.3 Anticipated Effects Under the Current IJC Rule Curves on Benthic Macroinvertebrates ....................................................................................10 3.4 Aquatic Plant Community............................................................................................11 3.4.1 Summary of Information on Aquatic Plants .................................................11 3.4.2 Effects on Aquatic Plants Under the Current IJC Rule Curves ....................14 3.4.3 Anticipated Effects on Aquatic Plants Under the Proposed ISC Rule Curves ........................................................................................................14 3.5 Amphibians and Reptiles .............................................................................................15 3.5.1 Summary of Information on Amphibians and Reptiles ...............................15 3.5.2 Effects on Amphibians and Reptiles Under the Current IJC Rule Curves ...15 3.5.3 Anticipated Effects Under the Current ISC Rule Curves on Amphibians and Reptiles ................................................................................................17 3.6 Aquatic Mammals - Muskrats, Beavers, and Otters ....................................................18 3.6.1 Summary of Information on Aquatic Mammals ..........................................18 3.6.2 Effects Under the Current IJC Rule Curves on Aquatic Mammals ..............18 3.6.3 Anticipated Effects Under the Proposed ISC Rule Curves on Aquatic Mammals....................................................................................................19 3.7 Grebes, Loons, and Marsh Birds ..................................................................................20 3.7.1 Summary of Information on Grebes, Loons, and Marsh Birds ....................20 3.7.2 Effects under the Current IJC Rule Curves on Grebes, Loons, and Marsh Birds ...........................................................................................................21 3.7.3 Anticipated Effects Under the Proposed ISC Rule Curves on Grebes, Loons, and Marsh Birds .............................................................................21 3.8 Predatory Birds ............................................................................................................22 i 3.8.1 Summary of Information on Predatory Birds ..............................................22 3.8.2 Effects Under the Current IJC Rule Curves on Predatory Birds ..................22 3.8.3 Anticipated Effects Under the Proposed IJC Rule Curves on Predatory Birds ..........................................................................................22 3.9 Cultural Resources .......................................................................................................23 3.9.1 Summary of Information on Cultural Resources .........................................23 3.9.2 Effects Under the Current IJC Rule Curves on Cultural Resources .............25 3.9.3 Anticipated Effects Under the Proposed ISC Rule Curves on Cultural Resources ...................................................................................................26 4.0 CONCLUSIONS......................................................................................................................27 4.1 "Are the data adequate for making decisions on the proposed rule curve changes?" ..27 4.2 "Are the concerns/perceived problems valid?" ............................................................28 4.3 "What further changes to the ecosystem components can be expected under the present mode of regulation?" .................................................................................28 4.4 "Would the proposed rule curve changes contribute, and by what magnitude, to meeting the objectives established for the proposed resolution to address the concerns/perceived problems?" .............................................................................28 4.5 "Would other causal factors (either outside of the IJC’s control or not being addressed by the proposal, such as restricted year-to-year variability) mask any effects of the proposed rule changes?" ..................................................................31 4.6 "Are all of the proposed changes required to achieve environmental resource benefits?" ...............................................................................................................32 4.7 "Are there alternative changes to the rule curves that would further enhance the economic and social values of the environmental resources?" ..............................32 5.0 RECOMMENDATIONS FOR ADDITIONAL OR FUTURE STUDIES ..............................33 6.0 LIST OF PREPARERS ...........................................................................................................34 7.0 LITERATURE REVIEWED ...................................................................................................35 Appendix A: Synopsis and Critique of Pertinent Literature and Investigations on Cultural Resources ........................................................................................................................ A-1 Appendix B: Synopsis and Critique of Pertinent Literature on Selected EcologicalResources ..B-2 List of Tables Table 1. Amphibians and reptiles in the Rainy and Namakan Area ..............................................16 Table 2. Summary of impacts of proposed ISC rule curves for Rainy Reservoir .........................29 Table 3. Summary of impacts of proposed ISC rule curves for Namakan Reservoir ....................30 ii EXECUTIVE SUMMARY The Rainy Lake watershed drains 38,600 square kilometers (km) (14,900 square miles) along the Minnesota-Ontario border. Power dams constructed in 1909 at International Falls-Fort Frances (Rainy Lake) and in 1914 at Kettle and Squirrel Falls (Namakan Reservoir) by the Boise Cascade Corporation regulate the water levels of Rainy, Little Grassy, Grassy, and Shoal Lakes, and the Namakan Reservoir which includes Namakan, Kabetogama, Sand Point, Crane and Little Vermilion Lakes. The operation of these dams is under the jurisdiction of the International Joint Commission (IJC) established under the treaty of January 11, 1909, between Great Britain and the United States. The International Rainy Lake Board of Control (IRLBC), created by the treaty and directive of the IJC, monitors lake levels and flows to ensure compliance with the IJC's Orders of Approval. In recent years, basin interests in the Rainy Lake watershed have expressed concerns regarding the effects of the current method of regulation on those interests. Many of these issues were formally submitted to the IJC with recommendations for changes in the Final Report and Recommendations of the Rainy Lake and Namakan Reservoir Water Level International Steering Committee (ISC), dated November 1993. A plan of study was developed by the IRLBC, at the request of the IJC, to identify and outline a detailed phase I review process to assess the adequacy of existing studies, data and information related to the regulation of Rainy Lake and the Namakan Chain of Lakes to determine if modifications to the existing Order for the Lakes are warranted. This review is a portion of the phase I effort identified in the plan