An assessment of the ecological impacts of inter‐basin water transfers, and their threats to river basin integrity and conservation

Abstract

ABSTRACT1. Detailed research into the ecological impacts of inter-basin water transfers (IBTs) is virtually nonexistent on a global scale. However, a growing awareness of the serious nature of such impacts-for example, the loss of biogeographical integrity, the loss of endemic biotas, the frequent introduction of alien and often invasive aquatic and terrestrial plants and animals, the genetic intermixing of once separated populations, the implications for water quality, the frequently drastic alteration of hydrological regimes, the implications for marine and estuarine processes, climatic effects, and the spread of disease vectors, amongst many others-demands a most urgent and world-wide appraisal of all current planning and research strategies.2. This paper first defines the types of extant IBTs, and details some case studies for three widely separated regions of the world, namely: south-eastern Australia, southern Africa, and the central and south-western parts of the United States of America. In doing so, it highlights the chronic paucity of ecological data on their impacts, while simultaneously emphasising their extreme complexities.3. Finally, we call for an international meeting on such schemes, as a matter of priority and extreme urgency, in order to assess the extent of IBTs, their geographical distribution, and their ecological and sociological impacts and implications.

Eco-environmental impact of inter-basin water transfer projects: a review

“…The water quality of the San Francisco Bay thus deteriorated and sea water intruded into the delta, forming a salinity gradient about 80 km long that extends from the western part of the Delta downstream to northern San Francisco Bay (Davies et al, 1992;Ma and Wang, 2011).…”

“…The open nature of the canal might act as an animal trap, which is one of the most contentious, emotive, and serious impacts of the water transfer canal (Davies et al, 1992). …”

“…Of the total, 57 % were reptiles, 22 % amphibians, 19 % mammals, and 2 % were birds. Certain endangered species, such as the Cape Vulture, Gyps coprotheres might have also been fall prey to the canal when feeding on large game which has drowned (Davies et al, 1992).…”

“…Otherwise, another way should be taken. Davies et al (1992) appealed that research should address not only a comprehensive approach to measuring the ecological impacts of IBTs, but also the evaluation of the ecological risks associated with them, as well as the development of monitoring programs which will allow alterations to be made to operational criteria, such that particularly deleterious impacts may be reduced. Davies et al (1992) also urged that an international workshop be conducted to address the lack of knowledge of the ecological impacts of IBTs, their extent and distribution, and the development of a suitable ecological ethic, monitoring programs, and the integration of IBTs into overall catchment planning and management.…”

The potential impact of an inter-basin water transfer project on nutrients (nitrogen and phosphorous) and chlorophyll a of the receiving water system

“…To alleviate water shortage problems in arid regions and promote development, a number of inter-basin water transfer projects have been launched in Australia, United States, Canada, China and India (Ghassemi and White, 2007), such as the Central Valley Project (Dunning, 1993), the Snowy Mountains Hydro-electric scheme (Erskine et al, 1999), the Great Lakes Basin diversions (Becker and Easter, 1997) and the Southto-North Water Transfer Project (SNWTP) (Berkoff, 2003). Any interbasin water transfer system can result in complex physical, chemical, hydrological and biological implications for the receiving system (Davies et al, 1992). Eutrophication has long been recognized as the primary water quality issue for most of the freshwater and coastal marine ecosystems in the world (Smith and Schindler, 2009).…”