ESTUARIES IN SOUTH AFRICA

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SPOEG RIVER ESTUARY: Hydrodynamics and mouth dynamics

	Hydrodynamics
	The mouth of the Spoeg River Estuary is almost always closed except during extreme flood periods. (Ref. 1).
	During dry periods, there is no surface runoff and the mouth is closed. The water body is then maintained in the lagoon by subsurface, fresh water seepage. There is however, a likelihood of extensive overtopping of the sandbar by storm waves during high tide periods. (Ref. 1).

	Mouth dynamics
	During a survey in 1981, there was a 100m wide sandbar separating the mouth from the sea, with its highest point approximately 1,5m above sea level. The crest of the sandbar was almost flat, but the adjoining beach was steep and of coarser sand than the bar itself (Ref. 1).
	The Spoeg River lies in a area of episodic rainfall, therefore the mouth is mostly closed and thus only opened in the event of a heavy flood.(Ref. 1).