Causes and Management of Salinity in the Breede River Valley, South Africa

Autor: J. H. Moolman, H.M. du Plessis, J. Kirchner, A.G. Reynders
Rok vydání: 1997
Předmět:
Zdroj: Hydrogeology Journal. 5:98-108
ISSN: 1435-0157
1431-2174
DOI: 10.1007/s100400050126
Popis: The water-distribution system of the Breede River Irrigation Scheme, South Africa, consists of the river itself, a series of canals, and various pumping schemes. However, the river not only conveys water to the various farms, but it also acts a a huge drainage ditch that receives all the drainage water from the irrigated areas. Since the 1960's, an awareness of salinity levels in the Breede River during the summer months has grown considerably. The perception of increasing salinity over time gave rise to concerns about the sustainability of using the water for irrigation of high-value, salt-sensitive crops. Various studies were undertaken to determine the origin of the river salinisation and how the situation could be managed. Isotopical an geohydrological investigations largely ruled out natural groundwater discharge as the major cause of river salinity; rather, irrigation return flow emanating from excessive leaching under irrigation is probably the major contributor. This contribution is aggravated by the mobilisation of salt in saline sedimentary deposits when these are disrupted during the preparation of new irrigation lands. River salinity is presently being managed by releases of freshening water. Complementary management options have been investigated or are under consideration, including construction of a return-flow intercepting drain or a high-level irrigation canal, and a reduction in irrigation leaching.
Databáze: OpenAIRE
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