Bot Estuary drainage area

The Bot Estuary has a relatively small drainage area, especially in view of the rather large estuary area.

The Bot Estuary drainage area includes the Bot River and Jakkalsriver which is the main water input into the estuary. Most of the rain in this area comes from the south and drops on the mountains areas west of the Bot River. The Swartriver which flows into the Bot River is a large area, but with significantly low rainfall. This area is in the rain shadow of the mountains across the south of the image. Even Caledon at the base of the mountains receives little rain with only a periodic river through Caledon.

The Afdaks River is a small drainage area, mostly in the rain shadow of the southern mountains. However the start of the Babilonstoring mountains do provide a source of water for the Afdaks River. It is interesting to note that the Onrus River has a very small drainage area, south of the Babilonstoring Mountains. A dam on the Onrus River is the main water supply to Hermanus.

The small river which flows mostly to Kleinmond, sometimes flows back into the the Estuary. When the Bot Estuary is full some of the water exits via Kleinmond.

The Bot Estuary lies below sea level, but can fill up to about 3m before it breaches again. Cape Nature breaches the Estuary artificially occasionally. Michael Austin has written about the last breach and this is available on this site.

This includes a report to BREF (Bot River Estuary Forum).