Estuaries are important natural
places. They provide goods and services that are economically and
ecologically indispensable. Estuaries provide vital nesting and feeding habitats for many aquatic plants and animals. Economically and environmentally, the Bot River Estuary is ranked as the 9th most important estuary in South Africa, being a nursery for certain species of estuarine and marine fish.
These are the main factors that negatively affect an estuary's health and cause habitat loss:
- Water abstraction and alien infestation in the catchment area, reducing the possibility of a natural breach
- Population growth in coastal watersheds
- Dredging, draining, bulldozing and paving
- Polluted runoff from urban, suburban and rural areas
- Dams
- Sewage discharges (septic and conservancy tanks, dumping of sewage)
- Coastal land loss and subsidence (climate change, altering of channels, changing river courses)
- Lack of understanding and apathy
Extract from the draft Bot River Estuary MMP 2018-01:
"If the Bot mouth is not breached artificially it will turn into a freshwater lake within five to ten years. As a result the invertebrate communities that serve as a food source for wading birds will change significantly, with crustaceans and molluscs being replaced by freshwater insects. Most of the 41 fish species that occur in the estuary are estuarine dependent or marine species and not adapted to fresh water condition. Mass mortalities of fish have occurred in the past when the estuary’s salinity fell below 6 practical salinity units (psu - seawater is 35 psu). The Bot Estuary is regarded as a highly important nursery area for marine fish, providing an ecosystem service valued at some R50 million, so this system’s function must be preserved."
The Bot River Estuary Forum (BREF) is a custodial organisation, concerned primarily with the protection and maintenance of this valuable ecosystem. The impact of human activities and intervention from the catchment area to the mouth have in the past and still continue to negatively affect this sensitive and precious ecosystem. In collaboration with governmental departments and nature conservation organisations, a new Bot River Estuary Mouth Management Plan is in the process of being developed, in addition to a revised Estuary Management Plan.
On 31 March 2016, Anton Wilhelm Bredell, Minister for Local Government, Environmental Affairs and Development Planning in the Western Cape, adopted the Western Cape Coastal Management Programme (WCCMP) in accordance with the National Environmental Management: Integrated Coastal Management Act (Act No. 24 of 2008).
Monitoring of Faecal Pollution
All stakeholders need to be kept informed of monitoring results with respect to breaching potential (natural and artificial), birds, fish, water quality, inflow, height and salinity. Monitoring of faecal coliforms is an important function in maintaining healthy water quality.
It is important to be aware of the
significance of bacterial indicators of faecal contamination for the
reports to be read in a meaningful way. This Basic Introduction, written by Ms Sue Matthews for Whale Coast Conservation in 2017, is an interesting and informative guide.
Click here to read the official 2018 reports of various estuaries, including the Bot.
More to follow...
