Autumn view of the Roaring Fork river in the western slope area of Colorado. © Bill Grindle/TNC A PRACTICAL GUIDE TO ENVIRONMENTAL FLOWS FOR POLICY AND PLANNING WITH NINE CASE STUDIES IN THE UNITED STATES Eloise Kendy, Colin Apse, and Kristen Blann with selected case studies by Mark P. Smith and Alisa Richardson MAY 2 0 1 2 CONTENTS Acknowledgments .......................................................................................................................................................................3 Foreword ............................................................................................................................................................................................4 Executive Summary .....................................................................................................................................................................5 1.0 Introduction ...........................................................................................................................................................................7 1.1 Background .....................................................................................................................................................................7 1.2 Purpose .............................................................................................................................................................................8 1.3 Structure and Scope of this Report ........................................................................................................................9 2.0 Case Studies ....................................................................................................................................................................... 10 2.1 Michigan’s Water Withdrawal Assessment Process ..................................................................................... 13 2.2 Massachusetts Sustainable Water Management Initiative ........................................................................ 18 2.3 Connecticut River Basin Ecosystem Flow Restoration ................................................................................. 23 2.4 Colorado Watershed Flow Evaluation Tool ....................................................................................................... 26 2.5 Connecticut Statewide Environmental Flow Regulations ........................................................................... 29 2.6 Middle Potomac River Basin Environmentally Sustainable Flows ........................................................... 33 2.7 Susquehanna River Basin Ecosystem Flow Recommendations ............................................................... 38 2.8 Ohio Thresholds for Ecological Flow Protection............................................................................................. 42 2.9 Rhode Island Stream Depletion Method ........................................................................................................... 45 3.0 Getting Environmental Flows to Scale: An Overview of the Process .................................................. 50 3.1 Understanding Water Availability: Building a Hydrologic Foundation ................................................... 50 3.1.1 What is the Hydrologic Foundation? ...................................................................................................... 50 3.1.2 Criteria for Hydrologic Model Selection ............................................................................................... 51 3.1.3 Components of the Hydrologic Foundation ........................................................................................ 51 3.1.4 General Observations and Summary ..................................................................................................... 53 3.2 Classifying River Types............................................................................................................................................. 55 3.2.1 Why Classify River Types? .......................................................................................................................... 55 3.2.2 General Approaches to Classification ................................................................................................... 55 3.2.3 Parameters Used for Classification ........................................................................................................ 56 3.2.4 General Observations .................................................................................................................................. 56 3.3 Describing Flow-Ecology Relationships ............................................................................................................. 57 3.3.1 Hypothesis Development ........................................................................................................................... 57 3.3.2 Quantitative Analysis ................................................................................................................................... 58 3.3.3 Hybrid Approaches ....................................................................................................................................... 59 3.3.4 General Observations .................................................................................................................................. 60 3.4 Making Flow-Ecology Relationships Operational: Applying Environmental Flow Science at a Regional Scale ....................................................................... 60 3.4.1 Establishing Ecological Condition Goals and Defining Acceptable Risk ................................. 61 3.4.2 Implementation: Putting Flow Standards into Practice ................................................................... 62 3.4.3 General Observations .................................................................................................................................. 64 4.0 Conclusions ......................................................................................................................................................................... 65 5.0 References............................................................................................................................................................................ 67 2 Acknowledgments This compilation would have been impossible without the forward thinking and hard work of many dedicated individuals. LeRoy Poff, Angela Arthington, Brian Richter, Bob Naiman, Stuart Bunn, Mike Acreman, Brian Bledsoe, Mary Freeman, Ken Rogers, Julian Olden, Rebecca Tharme, Dave Merritt, Jay O’Keefe, Rob Jacobson, Jim Henriksen, Jonathan Kennen, and Andy Warner knew that environmental flow protection had to be accelerated, and had the vision to scale up what previously had been a river-by-river endeavor to a practical framework for nationwide protection. Many of them, along with Michele DePhilip, John Sanderson, Sally Palmer, Judy Dunscomb, John Stark, Kim Lutz, Julie Zimmerman, Thomas Wilding, Nicole Rowan, Dave Armstrong, Stacey Archfield, Rodney Knight, Stephanie Flack, Claire Buchanan, Heidi Moltz, Paul Seelbach, Troy Zorn, Rob Burgholzer, Carlton Haywood, Tara Moberg, Dave Hamilton, Josh Knight, Mark P. Smith, David Sutherland, Chris Konrad, Rick Palmer, Austin Polebitski, John Hickey, Chris Hatfield, Rich Bowman, Todd Richards, and more brave, trusting souls accepted their challenge and led the first applications of this framework on the ground. We want to thank them not only for having the courage, resourcefulness, diplomacy, and tenacity to see these ambitious projects through, but also for sharing with us the lessons they learned along the way. Most of all, we applaud their pivotal roles in protecting and restoring environmental flows at a geographic scale never before imaginable. The clarity and accuracy of this report greatly benefited from constructive reviews of earlier drafts by Kim Lutz, Michele DePhilip, and Doug Shaw of The Nature Conservancy; Rick Eades of Nebraska Game and Parks Commission; Mike Robertson of Wyoming Game and Fish Department; Mary Davis of the Southeast Aquatic Resources Partnership; Jackie King of Water Matters; Alisa Richardson of the Rhode Island Department of Environmental Management; and Jennifer Phelan of the Research Triangle Institute International. 3 Foreword Freshwater scientists around the world acknowledge a crisis in biodiversity loss and diminished ecosystem function in streams, rivers, wetlands and lakes. One main culprit in this decline is human-caused change in the historical magnitude, frequency and timing of river flows that have supported key ecological processes and native species in diverse aquatic systems. The Ecological Limits of Hydrologic Alteration (ELOHA) framework arose as a response to the recognition that the rate of global hydrologic change was outpacing science’s ability to develop environmental flow guidelines one site at a time. A new scientific framework was needed, one to guide the development of environmental flow guidelines at a regional scale. Regional environmental flow management is extremely challenging. Not only are data needs great for underlying hydro- ecological models, but translation of science into policy and management necessarily occurs in a complex societal context constrained by governance structures, regulatory authorities and competing political interests. A comprehensive and scientifically sound framework