GROUNDWATER AND BIODIVERSITY CONSERVATION: A methods guide for integrating groundwater needs of ecosystems and species into conservation plans in the Pacific Northwest DECEMBER 2007 JENNY BROWN ABBY WYERS ALLISON ALDOUS LESLIE BACH photos credits (from top): springs at Borax Lake © Allison Aldous/TNC; Whychus Creek © Jim Yuskavitch; spring on Lower Crooked River © Marshall Gannett Acknowledgements: We are grateful to the Northwest Conservation Fund for financial support of this work. Additionally, this guide would not have been possible without the time and contributions of numerous colleagues. Our thanks goes to: • Brad Nye (Deschutes Basin Land Trust) for field trip to Camp Polk to see springs and groundwater-dependent ecosystems of Whychus Creek drainage • Colin Brown for retrieving literature from the Oregon State University library • Don Sada (Desert Research Institute) for review of KEAs for springs • Eloise Kendy (The Nature Conservancy) for review of earlier version of document • Jack Williams (Trout Unlimited) for review of KEAs for springs and Borax Lake chub and review of document • James Newton for review of groundwater-dependent species in Whychus Ck • Jason Dedrick (Crooked River Watershed Council) for field trip to the Lower Crooked • Jen Newlin-Bell (The Nature Conservancy) for design of the cover • John Crandall (The Nature Conservancy) for field testing the methods guide at Moses Coulee Conservation Area in WA • Jonathan Higgins (The Nature Conservancy) for review of KEAs for lakes and discussions of methods development • Jonathan LaMarche (OR Water Resources Department) for review of earlier version of document • Katharine Webster (University of Maine) for review of KEAs for lakes • Kathy Boomer (Smithsonian Institute) for review of earlier version of document • Laurie Morgan (WA Department of Ecology) for review of earlier version of document • Maret Pajutee (US Forest Service) for review of information on groundwater-dependent biodiversity • Marshall Gannett (US Geological Survey) for help in understanding groundwater in the Deschutes and for review of earlier versions of this document; • Michele Dephilip (The Nature Conservancy) for review of earlier version of document • Michelle McSwain (US BLM) for field trip to the Crooked River, discussion about groundwater-dependent biodiversity, FLIR data for the Deschutes and Lower Crooked River, and for review of earlier version of this document; • Mike Riehle (US Forest Service) for information on fish and stream temperatures in Whychus Creek • Natalie Bennon (The Nature Conservancy) for formatting and proofreading • Paul Measeles (OR Department of Agriculture) for review of earlier version of document • Peter Skidmore (The Nature Conservancy) for review of earlier version of document • Robert Wiggington (The Nature Conservancy) for review of earlier version of document • Scott McCalou (Deschutes Resources Conservancy) for field trip to Alder Springs and discussion of groundwater issues in the Whychus Creek drainage • Stephen Stanley (WA Department of Ecology) for review of earlier version of document • Steve Sebeysten (UC Berkeley) for help with KEAs and review of document • Tom Winter (US Geological Survey) for review of earlier version of document • Wendy Gerstel (consulting geologist) for review of earlier version of document Table of contents Acknowledgements............................................................................................................................ 1. INTRODUCTION ....................................................................................................................... 4 2. GROUNDWATER BASICS, IN RELATION TO ECOSYSTEMS AND SPECIES....................... 9 2.1 Groundwater:......................................................................................................................... 9 2.2 Water table........................................................................................................................... 10 2.3 Groundwater recharge: ........................................................................................................ 11 2.4 Groundwater discharge and availability to ecosystems:...................................................... 11 2.5 Groundwater movement ..................................................................................................... 14 3. IDENTIFYING AND MAPPING GROUNDWATER-DEPENDENT ECOSYSTEMS AND SPECIES ....................................................................................................................................... 16 3.1 Description of Groundwater-Dependent Ecosystems: ........................................................ 16 3.2 Overview of the importance of groundwater to biodiversity: ............................................. 17 3.3 Assessing the groundwater-dependence of specific ecosystems:........................................ 18 3.3.1. RIVERS:....................................................................................................................... 19 3.3.2. WETLANDS:............................................................................................................... 27 3.3.3. LAKES:........................................................................................................................ 39 3.3.4. SPRINGS: .................................................................................................................... 45 3.3.5. PHREATOPHYTIC ECOSYSTEMS:......................................................................... 49 3.3.6. CAVES:........................................................................................................................ 52 3.4 Identifying groundwater-dependent species:....................................................................... 53 3.5 Mapping GDEs.................................................................................................................... 58 4. DETERMINING GROUNDWATER REQUIREMENTS OF GDEs.......................................... 59 4.1 Groundwater key attribute................................................................................................... 60 4.2 Measurable indicators of key attributes............................................................................... 60 4.3 Desired future condition of indicators................................................................................. 60 4.4 Groundwater requirements of ecosystems........................................................................... 61 4.4.1. RIVERS:....................................................................................................................... 61 4.4.2. WETLANDS................................................................................................................ 65 4.4.3. LAKES......................................................................................................................... 69 4.4.4. SPRINGS: .................................................................................................................... 72 4.4.5. PHREATOPHYTIC ECOSYSTEMS.......................................................................... 75 4.5 Summary of groundwater requirements of ecosystems....................................................... 78 5. UNDERSTANDING GROUNDWATER FLOW SYSTEMS ...................................................... 83 5.1 The contributing area:.......................................................................................................... 83 5.2 Recharge areas:.................................................................................................................... 86 5.3 Groundwater Movement...................................................................................................... 97 5.3.1. Horizontal Flow Paths:................................................................................................. 97 5.3.2. Vertical flow paths: .................................................................................................... 101 6. SUMMARY.............................................................................................................................. 112 REFERENCES ............................................................................................................................ 113 Groundwater Methods Guide 1Table of Contents Figures: 1-1 Overview of Methods ............................................................................................................... 7 1-2 Location of the Whychus Creek Watershed in the Deschutes Basin of Oregon ...................... 8 2-1 Unconfined and confined aquifers.......................................................................................... 10 2-2 Water table.............................................................................................................................. 10 2-3 View of groundwater flow showing movement of water from surface to substrate .............. 12 2-4 Conceptual effects of groundwater well on water available for discharge to ecosystems ..... 13 2-5 Generalized depiction of nested groundwater flow systems .................................................. 14 2-6 Example of nested flow paths for the eastern slope of Puget Sound...................................... 15 3-1 Decision tree to determine likelihood of groundwater dependence in river ecosystems ....... 20 3-2 Estimated baseflow at locations in Wash. where baseflow analysis complete (map) ........... 21 3-3 Temperature