THE ECO-STATUS OF THE RIVERS

WITHIN THE GOURITZ RIVER CATCHMENT

The Breede-Gouritz Catchment Management Agency (BGCMA) has undertaken biomonitoring in the Gouritz sub-Water Management Area (WMA) for the purpose of implementation of the River Ecostatus Monitoring Programme (REMP) in the Western Cape. The aim of REMP is to determine the ecological status of the rivers in this catchment. This is achieved by sampling macroinvertebrates, using the South African Scoring System version 5 (SASS5) protocol. The sampling was done from June 2020 to February 2021.

The Gouritz sub-WMA is situated along the southern coast of South Africa and extends inland across the Little Karoo and into the Great Karoo. The area covers about 53 140 km2 and includes the Gouritz River catchment, as well as the catchments of the smaller coastal rivers that lie to the east and west of the Gouritz River mouth. The following rivers have been sampled: Doring, Touws, Buffels, Groot at J11J quaternary catchment, Groot River at J13C quaternary catchment, Gamka, Olifants, Kammanassie, Gouritz, Duiwenhoks, Goukou, Groot Brak, Malgas, Kaaimans, Diep, Karatara, Goukamma, Knysna, Gouna and Keurbooms. Most rivers in this subWMA are in a moderately modified condition (C ecological category), indicating a loss and change of natural habitat and biota have occurred but the basic ecosystem functions remain unchanged. Some are in largely natural condition (B ecological category), indicating that a small change in natural habitats and biota may have taken place but the ecosystem functions are essentially unchanged, while others are and in-between, with a largely natural to moderately modified condition (B/C ecological category).

The Gouritz sub-WMA is situated along the southern coast of South Africa and extends inland across the Little Karoo and into the Great Karoo. The area covers about 53 140 km2 and includes the Gouritz River catchment, as well as the catchments of the smaller coastal rivers that lie to the east and west of the Gouritz River mouth.

Only one was found to be in a largely modified condition, (D ecological category) indicating that a large loss of natural habitat, biota and basic ecosystem functions has occurred. The rivers are mainly impacted by alien vegetation, agricultural runoff, planting and irrigation of crops in riparian zone, water abstraction, bulldozing, flow modification by in-stream dams upstream, rubbish dumping, cattle trampling. Only the coastal rivers were flowing during this period, the inland rivers were dry throughout the entire sampling period.

The results have been compared with the recently determined Resource Quality Objectives (RQOs), and some sites are compliant with RQOs while others are not. Those that are not compliant will be monitored closely to see if the situation will improve or remain the same. If the conditions remain the same, this will trigger an investigation on what causes the sites to be non-compliant.

The REMP monitoring is an ongoing programme, where any degradation that will be detected will be recommended to be investigated and addressed.

The recommendations for the impacts on the rivers are as follows:

• Clearing of alien vegetation be undertaken in rivers that are affected, • Buffer areas be introduced and enforced where agricultural activities are impacting on water resources, especially during the water use authorisation process, • Implementation of ecological water requirements when instream dams are constructed, • Rehabilitation and restoration of riparian zones, • Education and awareness on protection of water resources be undertaken.

For any queries contact M Mlabateki-Public Relations & Marketing Officer on 023-346 8000