Western Indian Ocean Ecosystem Guidelines and Toolkits Guidelines for the Assessment of Environmental Flows in the Western Indian Ocean Region Guidelines for the Assessment of EFlows in WIO region Western Indian Ocean Ecosystem Guidelines and Toolkits Guidelines for the Assessment of Environmental Flows in the Western Indian Ocean Region Published by the United Nations Environment Programme/Nairobi Convention Secretariat. Copyright © Nairobi Convention 2020. All rights reserved: The findings, interpretations and conclusions expressed herein are those of the authors and do not necessarily reflect the views of the Contracting Parties to the Nairobi Convention. Rights and Permissions: The information in this report is copyrighted, therefore, copying and/or transmitting portions of this report without permission of the Nairobi Convention may be a violation of applicable law. How- ever, the Nairobi Convention encourages dissemination and use of the materials in this report. Disclaimer: This publication has been produced by the United Nations Environ- ment Programme-Nairobi Convention and WIOMSA with the kind assistance of various regional governments, Non-Governmental Organizations, Civil Society Organizations, as well as of individuals through the Global Environment Facility (GEF) funded WIOSAP pro- ject and SIDA funded MASMA project executed by the Convention and WIOMSA respectively. The report is copyrighted entirely to the Nairobi Convention and WIOMSA. Compiled and prepared by: Cate Brown and Jackie King, with contributions from Lara Van Niekerk and Susan Taljaard. Series Editor: Matthew D. Richmond Designed by: Marco Nunes Correia Coordinated by: Jared Bosire, Julius Francis and Timothy Andrew Citation: UNEP-Nairobi Convention/WIOMSA (2020). Guidelines for the Assessment of Environmental Flows in the Western Indian Ocean Region. UNEP, Nairobi, 79 pp. Western Indian Ocean Ecosystem Guidelines and Toolkits ISSN: 2714-1942 Table of Contents 1. Introduction ___________________________________________________________________________ 1 1.1 Background to the development of the Guidelines ______________________________________________ 1 1.2 Structure of the Guidelines _____________________________________________________________________ 3 1.3 Definitions______________________________________________________________________________________ 3 2. Environmental Flows __________________________________________________________________ 5 2.1 The need for EFlows ____________________________________________________________________________ 5 2.2 The effects of human developments on rivers and estuaries ____________________________________ 6 2.3 Climate change and EFlows ____________________________________________________________________ 8 2.4 Negotiating objectives for river and estuarine ecosystem status ________________________________ 9 2.5 An integrated river basin management approach ______________________________________________ 10 3. EFlows Assessments _________________________________________________________________ 13 3.1 EFlows Assessment methods _________________________________________________________________ 13 3.2 Trends in EFlows Assessments in the WIO region _____________________________________________ 18 3.3 Overview of information provided by EFlows Assessments ____________________________________ 20 3.3.1 EFlows information to support the sustainability of marine ecosystems ___________________ 22 4. Undertaking an EFlows Assessment _________________________________________________ 25 4.1 Nature of the assessment, budget, method and team __________________________________________ 25 4.1.1 Purpose and scope _______________________________________________________________________ 25 4.1.2 Budget ___________________________________________________________________________________ 25 4.2 Select an appropriate EFlows Assessment method ____________________________________________ 27 4.2.1 Supporting models _______________________________________________________________________ 30 4.2.2 Consideration for the selection of methods for WIO EFlows Assessments _________________ 30 4.3 EFlows Assessment team _____________________________________________________________________ 32 4.4 Spatial and temporal units of assessment _____________________________________________________ 32 4.4.1 Site selection _____________________________________________________________________________ 32 4.4.2 Time-scales for analysis __________________________________________________________________ 34 4.4.2.1 Climate change ______________________________________________________________________ 34 4.4.2.2 Sediment ____________________________________________________________________________ 35 4.4.3 Baseline conditions _______________________________________________________________________ 35 4.5 Stakeholder engagement ______________________________________________________________________ 35 4.6 Scenarios _____________________________________________________________________________________ 36 4.7 Biophysical and social indicators ______________________________________________________________ 37 4.7.1 Mapping indicator links ___________________________________________________________________ 37 4.8 Data requirements ____________________________________________________________________________ 37 4.8.1 Physical/chemical ________________________________________________________________________ 37 4.8.1.1 Hydrology ____________________________________________________________________________ 37 4.8.1.2 Hydraulics ___________________________________________________________________________ 45 4.8.1.3 Water quality ________________________________________________________________________ 46 4.8.1.4 Sediment and geomorphology _______________________________________________________ 46 4.8.2 Biology ___________________________________________________________________________________ 46 4.8.3 Social ____________________________________________________________________________________ 47 4.9 Field visits _____________________________________________________________________________________ 47 4.10 Set-up and calibrate EFlows models __________________________________________________________ 47 4.11 Analyse the scenarios ________________________________________________________________________ 48 4.12 Reporting ____________________________________________________________________________________ 48 4.12.1 Other deliverables _______________________________________________________________________ 50 EFlows Assessments iii 5. Managing data limitations ___________________________________________________________ 51 6. Mainstreaming the uptake of EFlows Assessments __________________________________ 53 6.1 Deciding on EFlows allocations ________________________________________________________________ 53 6.2 Harmonizing policies and working with government agencies _________________________________ 54 6.3 Building managerial and technical capacity in EFlows Assessment ____________________________ 55 6.4 EFlows information systems __________________________________________________________________ 55 6.5 Funding to support EFlows ____________________________________________________________________ 56 7. References __________________________________________________________________________ 59 iv EFlows Assessments List of Tables Table 1. Commonly-used EFlows Assessment methods for rivers. __________________________________ 16 Table 2. Commonly-used EFlows Assessment methods for estuaries. ______________________________ 17 Table 3. Actions required for including the nearshore marine environment into an EFlows Assessments. ______________________________________________________________ 18 Table 4. Definitions of the ecological condition categories. __________________________________________ 21 Table 5. Strengths and weakness of categories of EFlows Assessment methods. ___________________ 23 Table 6. Personnel time (days) for different resolution levels of flow assessments per river, excluding travel and stakeholder liaison time, and disbursements. __________________________ 26 Table 7. Personnel time (days) for different resolution levels of flow assessments per estuary, excluding travel and stakeholder liaison time, and disbursements. __________________________ 27 Table 8. Decision matrix for selection of a suitable EFlows Assessment method. ____________________ 28 Table 9. Potential members of an EFlows Assessment technical team. ______________________________ 33 Table 10. Example of biophysical EFlows indicators used for a site on the Zambezi River and for the Great Berg estuary. _____________________________________________________________ 38 Table 11. Basic data/information used for five different EFlows Assessment methods for rivers. _____ 42 Table 12. Basic data/information requirements for five different EFlows Assessment methods for estuaries. _____________________________________________________________________ 44 Table 13. Examples of ecologically relevant summary statistics that can be calculated from hydrological time-series of different time-steps. ____________________________________________ 46 Table 14. Sustainable use of rivers: key attributes of EFlows implementation. _________________________ 53 EFlows Assessments v List of Plates Plate 1. Sampling macro-invertebrate in the Zambezi River. __________________________________________ 2 Plate 2. Mangrove fringed esturary in Zanzibar, providing a natural barrier to sea-level rise. ___________ 9 Plate 3. Setting nets to sample