Technical Foundation for Future Management of Vancouver Lake
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DRAFT Technical Foundation for Future Management of Vancouver Lake November 2008 Prepared by the Vancouver Lake Watershed Partnership’s Technical Group Contents Contents ..............................................................................................................................................iii Glossary ............................................................................................................................................... v 1. Introduction............................................................................................................................... 1-1 Background ................................................................................................................................ 1-1 Purpose of This Document....................................................................................................... 1-1 Overview of Vancouver Lake .................................................................................................. 1-2 Character of the Lake and the Larger Watershed ....................................................... 1-2 History of Vancouver Lake ............................................................................................ 1-2 Ownership and Surrounding Land Uses ..................................................................... 1-4 2. Hydrology, Vegetation, Fish and Wildlife .......................................................................... 2-1 What Makes Shallow Lakes Different?................................................................................... 2-1 Two States of Shallow Lakes.................................................................................................... 2-1 Hydrology of Vancouver Lake ................................................................................................ 2-2 Columbia River, the Flushing Channel, and Lake River ........................................... 2-2 Burnt Bridge and Salmon Creek.................................................................................... 2-3 Smaller Tributaries .......................................................................................................... 2-4 Groundwater .................................................................................................................... 2-4 Typical Water Year .......................................................................................................... 2-4 Lake Bottom...................................................................................................................... 2-5 Fish, Wildlife, Invertebrates, and Aquatic Vegetation at Vancouver Lake ....................... 2-5 Fish..................................................................................................................................... 2-6 Wildlife.............................................................................................................................. 2-6 Invertebrates..................................................................................................................... 2-6 Aquatic Vegetation.......................................................................................................... 2-6 3. Issues at Vancouver Lake........................................................................................................3-1 Nuisance Algal Blooms............................................................................................................. 3-2 What Is the Concern? ...................................................................................................... 3-2 What Is the Extent at Vancouver Lake?........................................................................ 3-2 What Is the Likely Source? ............................................................................................. 3-3 Excess Nutrients ........................................................................................................................ 3-3 What Is the Concern? ...................................................................................................... 3-3 What Is the Extent at Vancouver Lake?........................................................................ 3-3 What Is the Source? ......................................................................................................... 3-4 Bacteria and Pathogens............................................................................................................. 3-4 What Is the Concern? ...................................................................................................... 3-4 What Is the Extent at Vancouver Lake?........................................................................ 3-4 What Is the Source? ......................................................................................................... 3-4 Temperature and Dissolved Oxygen...................................................................................... 3-5 What Is the Concern? ...................................................................................................... 3-5 What Is the Extent at Vancouver Lake?........................................................................ 3-5 What Is the Source? ......................................................................................................... 3-5 CHAPTER 0 iii CONTENTS Toxic Contaminants .................................................................................................................. 3-5 What Is the Concern? ...................................................................................................... 3-5 What Is the Extent at Vancouver Lake?........................................................................ 3-6 What Is the Source? ......................................................................................................... 3-6 Low Water Clarity..................................................................................................................... 3-7 What Is the Concern? ...................................................................................................... 3-7 What Is the Extent at Vancouver Lake?........................................................................ 3-7 What Is the Source? ......................................................................................................... 3-7 Sedimentation ............................................................................................................................ 3-7 What Is the Concern? ...................................................................................................... 3-7 What Is the Extent at Vancouver Lake?........................................................................ 3-8 What Is the Source? ......................................................................................................... 3-8 Exotic Plant Species................................................................................................................... 3-8 What Is the Concern? ...................................................................................................... 3-8 What Is the Extent at Vancouver Lake?........................................................................ 3-9 What Is the Source? ......................................................................................................... 3-9 Lack of Aquatic Habitat............................................................................................................ 3-9 What Is the Concern? ...................................................................................................... 3-9 What Is the Extent at Vancouver Lake?........................................................................ 3-9 What Is the Source? ......................................................................................................... 3-9 4. Data Gaps................................................................................................................................... 4-1 Technical Questions .................................................................................................................. 4-1 Available Information..................................................................................................... 4-2 Data Gaps.......................................................................................................................... 4-3 Physical Environment (Hydrology/Hydraulics).................................................................. 4-3 Available Information..................................................................................................... 4-4 Data Gaps.......................................................................................................................... 4-5 Available Information..................................................................................................... 4-6 Data Gaps.......................................................................................................................... 4-7 5. Technical Strategy .................................................................................................................... 5-1 Strategy Overview..................................................................................................................... 5-1 Studies........................................................................................................................................