The Don Sahong Dam: Potential Impacts on Regional Fish Migrations, Livelihoods and Human Health Ian G. Baird, PhD August, 2009 Author’s Contact Information: Ian G. Baird, PhD, Affiliate, POLIS Project on Ecological Governance, University of Victoria, P.O. Box 3060, University House 4, Victoria, B.C., Canada V8W 3R4
[email protected] www.polisproject.org Photo Credits: All photos were taken by Ian G. Baird 1 Table of Contents Acronyms 3 Executive Summary 4 1. Introduction 5 Figure 1. Proposed location of the Don Sahong Dam and study sites between Khone Falls and Vientiane Municipality 7 2. The Nature of the Mekong River Basin and Fish Migrations 8 3. The Khone Falls and the Hou Sahong Channel 9 Figure 2. Just below the Don Sahong Dam site 9 4. Fish Migrations in the Khone Falls Area 10 Table 1. Fish species that migrate up the Mekong River from the Tonle Sap River each dry season (adapted from Baird et al. 2003) 12 5. Methodology 13 6. Results 14 6.1 The Extent of Upstream Fish Migrations 14 Table 2. Fish species’ presence and absence along Mekong River between the Khone Falls and Vientiane Municipality 16 6.2 The Importance of Upstream Fish Migrations for Fisheries above Khone Falls 18 Figure 3. A fish trap on the Hou Xang Pheuak 19 6.3 Numbers of People Expected to be Impacted Upstream 19 6.4 The Importance of Upstream Fish Migrations for Fisheries below Khone Falls 20 6.5 The Impacts of the Don Sahong Dam to Downstream Fisheries 21 6.6 Numbers of People Expected to be Impacted Downstream 23 6.7 Gas Supersaturation below the Don Sahong Dam 24 6.8 Habitat Destruction below the Don Sahong Dam 24 6.9 Cumulative Impacts on Fish and Fisheries 24 7.