Effects of Groundwater Extraction and River Regulation on Coastal Freshwater Resources

Abstract

AbstractWith increasing coastal development based on the so-called “blue economy”, freshwater resources in nearshore areas have come under increased pressure. Improved coastal zone management is needed to sustain coastal ecosystems and resource use, as well as support for industries and infrastructure related to blue economic development. We present and synthesize here case studies of how groundwater extraction and river regulation schemes (including dam construction) have affected natural coastal environments. This includes consideration of some unanticipated consequences of these activities. Dams, even when located hundreds of kilometers upstream, can still result in significant environmental changes to estuaries, deltas, and adjacent seas. Modifications and engineering of rivers has resulted in changing volumes and compositions of river flow and submarine groundwater discharge. Groundwater and/or hydrocarbon extraction in deltaic settings often leads to subsidence, which results in flooding and coastal erosion. The examples in this chapter, drawn mostly from Asia, illustrate issues that are developing worldwide. We show how application of the most up-to-date scientific approaches, such as natural geochemical tracers (e.g., radium isotopes), can provide useful information in support of sustainable management actions. These issues are presented to call for more science-based and ecosystem-inclusive management plans to achieve “blue economy” goals.KeywordsCoastal freshwater useGround water extractionCoastal subsidenceRiver regulationIsotope geochemistry