Impacts of Mainstream Hydropower Development on Fisheries and Human Nutrition in the Lower Mekong

Abstract

Dams provide energy and irrigation water, but also alter natural water flows that support fisheries. This tradeoff presents a risk for human nutrition in regions dependent on aquatic foods, including the Lower Mekong Basin (LMB), where over 100 dams are planned or in construction. Previous models estimate significant reductions in fishery production resulting from these dams. This study estimates the number of new nutritionally insecure people (i.e., those at risk for nutritional deficiencies) associated with Mekong damming. We calculated population-level nutritional needs based on the Estimated Average Requirements (EARs) for Cambodia and the entire LMB. We then estimated fish-derived nutrient supplies by integrating data on annual fishery production and fish nutrient content for a wide range of species. Finally, we synthesized available literature and modeling results on the impacts of damming on fisheries production, and estimated the consequent impact on inadequate intakes of protein, zinc, niacin, thiamin, riboflavin, and calcium, as well as potential vulnerability to losses of dietary iron. Hydropower development could restrict access to subsistence fish from the Mekong River Basin and lead to increased risk of nutritional deficiencies in Cambodia and the LMB. Our median estimates suggest that by 2030, relative to 2010, inadequate intakes could lead to an increased population at risk of nutritional deficiencies in the LMB by 0.21 to 2.23 million people for protein, 0.12 to 1.17 million people for zinc, 0.41 to 1.58 million people for niacin, 0.47 to 0.87 million people for thiamin, 0.70 to 2.31 million people for riboflavin, and approximately 10,000 people for calcium. This increased population at risk is additional to those currently malnourished. We then calculated that the average iron intake of many age-sex groups (constituting 58% of the population) will be below 150% of their EAR in 2030, indicating a potential risk of increased inadequate iron intake. Fish is the main source of animal source foods and critical micronutrients in the LMB. In the absence of mitigation efforts, any reductions in fishery production could increase already high levels of nutrient deficiency, creating a widespread risk of nutrition insecurity.

Maintaining Diversity of Integrated Rice and Fish Production Confers Adaptability of Food Systems to Global Change

“…As of 2013, capture fisheries still contributed substantially to inland fish production in Bangladesh (36%), Cambodia (86%), and Myanmar (49%; FAO, 2020a). While growth in aquaculture production has continued, the relative contributions of inland capture fisheries remain sizeable in terms of fish production (Edwards et al, 2019;Funge-Smith and Bennett, 2019), food provision (Arthur and Friend, 2011;Fluet-Chouinard et al, 2018), and nutrition (Halwart, 2006;Kawarazuka and Béné, 2011;Thilsted et al, 2016;Golden et al, 2019).…”

“…Water demand is a growing challenge due to recurrent dry periods and increased frequency and/or severity of adverse conditions during rice cultivation (Chhinh et al, 2014;Thangrak et al, 2020), the limited capacity of existing reservoirs in the Tonle Sap basin (Johnston et al, 2014), "water-scavenging" irrigation at farm level (Mukherji et al, 2009), and large scale upstream hydropower development affecting the Mekong and its inflow into the Tonle Sap (Arias et al, 2014). This last factor has already been linked to an expected decline in food and nutrition security through loss of fish availability (Golden et al, 2019). Local mitigation measures such as effective water management, "fish friendly" designs for irrigation development (McCartney et al, 2019), and continued community fish refuge support and scaling of best management practices (Kim et al, 2019) are essential for sustaining rice field fisheries.…”

Linking Environmental Policy Integration and the Water-Energy-Land-(Food-)Nexus: A Review of the European Union’s Energy, Water, and Agricultural Policies

“…Others instead refer to the nexus among 'water, energy and land' (WEL Nexus) [13,44,45], or a combination of the two [46,47]. Also, some publications specifically investigate certain relations or sectors, such as the nexus between seafood and hydropower [48]. Others again explicitly include a fourth sector-namely climate-to the nexus [11,45,49,50].…”

“…In accordance with the nexus understanding, the roadmap further calls for a comprehensive and integrative management approach to achieve these objectives [85]. Such overarching strategies and plans-despite their reference to the main nexus idea-currently lack an operational implementation in day-to-day policy making [48].…”

Agricultural Innovations to Reduce the Health Impacts of Dams

“…By stemming natural flood regimes, dams disrupt the reproduction of many fish species, affecting inland fisheries [11]. Disruptions to fisheries can, in turn, affect fishing livelihoods and increase the number of people at risk for nutritional deficiencies [28]. Environmental disruption can also facilitate the transmission of infectious diseases.…”