ESTUARIES IN SOUTH AFRICA

Main Page	General Information	Catchment Characteristics	Land and Estuary Uses	Ecology
Threats	Hydrodynamics and mouth dynamics	Physical Features	Climate	References
LOURENS RIVER ESTUARY: Water Quality

	Physio-chemical Characteristics
	During 1982, a tidal interchange was observed up to 1 300m from the Lourens River Mouth. During summer the estuary became hypersaline, as opposed to the *salinity* during winter, when the estuary became an almost completely fresh system (Ref. 2).
	In 1982, average water temperatures varied between 12°C in winter and 27°C in summer (Ref. 2).
	In 1982, transparency of the water was measured with a Secchi disc, which gave readings of approximately 100cm, when the mouth was closed and 74cm, when the mouth was opened (Ref. 2).
	The water was reported to be well oxygenated during the survey period from December 1981 to May 1982 (Ref. 2).
	The pH measurements were lowest (between 4.1 and 5.4) during February and March 1982, due to the influx of water (pH = 3) from the AECI drain (Ref. 2).
	As far as nutrients were concerned, it was concluded that nitrate concentrations in the estuary can periodically reach very high levels (Ref. 2).
	Pollution
	Pesticides, herbicides and fertilisers from the upper catchment reach the Lourens Estuary via the Lourens River. (Ref.2.)
	Storm water drains from the adjacent residential areas drain into the Lourens Estuary via the Lourens River. (Ref.2.)
	Waste products are dumped all along the river, polluting the estuary and subsequently also the adjacent beach.