C S A S S C C S Canadian Science Advisory Secretariat Secrétariat canadien de consultation scientifique Research Document 2012/039 Document de recherche 2012/039 National Capital Region Région de la capitale nationale Review of approaches and methods to Examen des approches et des méthodes assess Environmental Flows across d’évaluation des débits Canada and internationally environnementaux au Canada et à l’échelle internationale Linnansaari, T.1, Monk, W.A.2, Baird, D.J.2 and Curry, R.A.1 1 Canadian Rivers Institute, University of New Brunswick, Department of Biology, P.O. Box 4400, Fredericton, New Brunswick, E3B 5A3 2 Environment Canada, Canadian Rivers Institute, University of New Brunswick, Department of Biology, P.O. Box 4400, Fredericton, New Brunswick, E3B 5A3 This series documents the scientific basis for the La présente série documente les fondements evaluation of aquatic resources and ecosystems in scientifiques des évaluations des ressources et Canada. As such, it addresses the issues of the des écosystèmes aquatiques du Canada. Elle day in the time frames required and the traite des problèmes courants selon les documents it contains are not intended as échéanciers dictés. Les documents qu‘elle definitive statements on the subjects addressed contient ne doivent pas être considérés comme but rather as progress reports on ongoing des énoncés définitifs sur les sujets traités, mais investigations. plutôt comme des rapports d‘étape sur les études en cours. Research documents are produced in the official Les documents de recherche sont publiés dans language in which they are provided to the la langue officielle utilisée dans le manuscrit Secretariat. envoyé au Secrétariat. This document is available on the Internet at: Ce document est disponible sur l‘Internet à: www.dfo-mpo.gc.ca/csas-sccs/ ISSN 1499-3848 (Printed / Imprimé) ISSN 1919-5044 (Online / En ligne) © Her Majesty the Queen in Right of Canada, 2013 © Sa Majesté la Reine du Chef du Canada, 2013 TABLE OF CONTENTS ABSTRACT .................................................................................................................................................. iv RÉSUMÉ ...................................................................................................................................................... vi 1. INTRODUCTION ....................................................................................................................................... 1 1.1 NEEDS FOR ENVIRONMENTAL FLOW FRAMEWORK IN CANADA ........................................ 1 1.2 PURPOSE AND SCOPE OF REVIEW ......................................................................................... 2 2. CONFLICTING TERMINOLOGY OF "ENVIRONMENTAL FLOWS" ....................................................... 3 Instream Flow Need / Requirement ............................................................................................ 3 Environmental Flow ..................................................................................................................... 3 Ecological Flow: .......................................................................................................................... 4 Base Flow: ................................................................................................................................... 4 3. REVIEW OF ENVIRONMENTAL FLOW ASSESSMENT METHODOLOGY ........................................... 4 3.1 HYDROLOGICAL METHODS ...................................................................................................... 5 3.1.1 The Tennant method and its derivatives ............................................................................ 5 3.1.2 Flow Duration (Exceedence) curves, and statistical low-flow frequency methods ............. 6 3.1.3 Indicators of Hydrologic Alteration (IHA) and the Range of Variability Approach (RVA) .... 7 3.1.4. Percentage of Flow (POF) methods, Sustainability Boundary Approach (SBA) and Presumptive Standards ..................................................................................................... 8 3.1.5 Strengths, weaknesses and data requirements of hydrological methods ........................ 10 3.2 HYDRAULIC RATING METHODS .............................................................................................. 11 3.2.1 General description and common methods ..................................................................... 11 3.2.2. Strengths, weaknesses and data requirements of hydraulic methods ............................ 12 3.3 HABITAT SIMULATION METHODS ........................................................................................... 13 3.3.1 Habitat simulation methods at the microhabitat scale ...................................................... 13 3.3.2 Strengths, weaknesses and data requirements of habitat simulation methods ............... 18 3.3.3 Generalized (statistical) habitat models ........................................................................... 19 3.3.4. Mesohabitat models ........................................................................................................ 20 3.3.5 Bioenergetic models ......................................................................................................... 23 3. 4 HOLISTIC METHODS AND OTHER ANALYTICAL FRAMEWORKS FOR DEVELOPING ENVIRONMENTAL FLOW STANDARDS ................................................................................ 23 3.4.1 Building Block Methodology (BBM) .................................................................................. 24 3.4.2 Downstream Response to Imposed Flow Transformation (DRIFT) ................................. 25 3.4.3 Benchmarking and the derived frameworks ..................................................................... 27 3.4.4 The Ecological Limits of Hydrologic Alteration (ELOHA) Approach ................................. 28 3.4.5 Strengths, weaknesses and data requirements of holistic methods ................................ 33 4. SUMMARY OF ENVIRONMENTAL FLOW GUIDELINES CURRENTLY USED IN CANADA AND INTERNATIONALLY .............................................................................................................................. 34 4.1 CURRENT ENVIRONMENTAL FLOW GUIDELINES IN CANADA ........................................... 34 4.1.1 British Columbia ............................................................................................................... 35 4.1.2 Alberta .............................................................................................................................. 35 4.1.3 Saskatchewan and Manitoba ........................................................................................... 36 4.1.4 Ontario .............................................................................................................................. 36 4.1.5 Quebec ............................................................................................................................. 36 4.1.6 Atlantic Provinces (New Brunswick, Nova Scotia, Prince Edward Island and Newfoundland and Labrador).......................................................................................... 37 4.1.7. Eastern and Western Arctic ............................................................................................ 37 4.2 ENVIRONMENTAL FLOW GUIDELINES IN OTHER SELECT COUNTRIES ........................... 37 4.2.1 USA .................................................................................................................................. 37 4.2.2 European Union ............................................................................................................... 38 4.2.3 Australia, South-Africa and New-Zealand ........................................................................ 38 ii 5. ACKNOWLEDGEMENTS ....................................................................................................................... 39 6. REFERENCES ........................................................................................................................................ 39 TABLES ....................................................................................................................................................... 50 FIGURES .................................................................................................................................................... 58 APPENDIX A: List of Abbreviations ............................................................................................................ 72 APPENDIX B. The current method of establishing minimum or environmental flows in some European countries................................................................................................................................................. 73 iii Correct citation for this publication: Linnansaari, T., Monk, W.A., Baird, D.J. and Curry, R.A. 2013. Review of approaches and methods to assess Environmental Flows across Canada and internationally. DFO Can. Sci. Advis. Sec. Res. Doc. 2012/039. vii + 75 p. ABSTRACT Freshwater resources are under increasing threat from anthropogenic activities, both in terms of consumptive and non-consumptive use. The increasing societal demands for water have led to substantial flow alterations in rivers in Canada. Flow alteration can be directly linked to impacts on the physical and chemical attributes and processes of rivers and subsequent ecological changes. In addition to increasing