ESTUARIES IN SOUTH AFRICA

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GOURITZ ESTUARY: Hydrodynamics and mouth dynamics

	Hydrodynamics
	The tidal lag in the estuary was in 1987 approximately 2 hours at low tide , at the head of the estuary (Ref. 1).
	Saline water seemed to penetrate up to 2 km upstream of the road bridge at “Die Eiland” during high tide. This point is the absolute upper limit of estuarine conditions as confirmed by the vegetation.(Ref. 1).

	Mouth dynamics
	The mouth of the Estuary is normally about 18m wide but during the rainy season and at high tide, it may be wider (Ref. 4). During the floods in August 1986, the mouth was approximately 40m wide (Ref. 5).
	In the past the mouth must have been closed for various lengths of time (Ref. 1). During times of low flow, the sandspit is build up to a state of near closure (Ref. 1). The mouth is opened during floods, when the sediments are washed out to sea, forming an offshore delta, from where the sand is returned to the sandspit during calmer conditions.
	Although the Gourits River mouth occasionally forms a double spit, as was the situation in 1984, the mouth as a rule consists of an extensive sandspit on the western side with rocks lining the eastern shore of the mouth.