After two years in intensive care Hartbeespoort Dam is showing welcome signs of recovery

(2009-09-28)

After two years in intensive care, Hartbeespoort Dam is already showing visible signs of a recovery in progress. According to the Department of Water Affairs (DWA) this is directly attributable to the Harties Metsi a me Integrated Remediation Programme.

Mr Petrus Venter, DWA leader for the programme, yesterday claimed that the improved results can to a great extent be ascribed to the actions undertaken by those involved in the remediation plan. These include the continuous removal of algae and hyacinth, re-establishment of the shoreline vegetation, manufacturing of floating wetlands as well as progress with restructuring the food web in the dam.

One visible sign of the current pristine condition of the Dam was the report by a monitoring team that there was clarity of water depth of up to five metres below the surface in some areas of the Dam.

Prospects for further improvement is good because of the continuous removal and control of algae and hyacinth; between January and August this year 4460m³ of algae, 7277 m³ of hyacinth and 169 tons of debris were removed from the Dam. “These actions have reduced the deposit of organic material to the bottom of the Dam,” Mr Venter said, “organic material acts as the fuel to mobilise more nutrients from the sediments.”

The fishing project
Despite continued damage to the contractor’s nets and equipment, the fishing project is also making good progress. The purpose of the fishing project is to alleviate the negative impact accompanied by eutriphication (nutrient enrichment) of the Dam and its aim is to restructure the presently unhealthy aquatic food web.

Fish species which re-introduce nutrients to the water column are targeted for removal. They include: bottom feeders such as catfish and carp. Also targeted are zooplankton feeders which reduce the uptake of algal to the foodweb such as the canary kurper.

Fishing efforts have been renewed and there has been a remarkable increase in the fish catches between 4 and 14 August 2009 with 3.956 tons of fish netted.

Fish have mainly been caught in the areas of Meerhof, Oberon, De Rust and Kommando Nek. From February 2008 to date a total of 45 530.95 kgs of fish have been removed. Long lines will also be used over the next few months for targeting catfish as this species will soon start feeding with increased intensity in preparation for the spawning season.

Shoreline rehabilitation
With regards to the shoreline rehabilitation, teams are busy removing exotic plants in order to start planting in spring. The manufacturing of floating wetlands is progressing well and they produce on average about 50 x 20m² units per month. A number of estates have indicated their desire to participate in the floating wetlands project by purchasing, installing and maintaining them on their own immediate shorelines. This is especially relevant where the shoreline has been irreparably damaged due to various factors.

The earthworm project
The vermiculture (earthworm) project is making progress with about 800 m³ of compost which is currently in process and 25 m³ of pure vermicast at the damwall.

The Vermi-compost produced is of a high quality and algae and hyacinth are used in this process. Three other composting sites were established at Schoemansville Oewer Club, Ifafi Conservation area and the inlet of Saartjiespruit. The total stock of earthworms now stands at 2 300kg.

The information centre
The information centre is open during the week for school groups by arrangement and staffed on Saturdays between 9:00 and 14:00. It’s situated just west of the tunnel.

The public and especially schools are encouraged to visit the centre. Schools are welcome to contact the Harties metsi a me offices to arrange for visits to the centre as well as visiting other aspects of the programme.

The Resource Management Plan
The Resource Management Plan for Hartbeespoort Dam has been developed and made public for comment. Although the review period
ended on 30 April 2009 various requests have been received for a further meeting to discuss the draft RMP.

This will be done as soon as the comments received have been incorporated into the document (planned for the end of November 2009).

For further information contact the "Harties metsi a me" office at either telephone 012-207-9911 or e-mail harties@dwaf.gov.za. You can also visit the web site at www.dwa.gov.za/harties

Worth noting:
What a pleasure to publish the occasional good news story for a change.
In reporting on a water bird count around the Dam in July conducted by WESSA for the Animal Demographic Unit of the University of Cape Town, Mr John Wesson of WESSA remarked that the number of birds counted in July nearly doubled compared to the count in January. Does that mean that the word is spreading among the water birds that Harties is now a salubrious place to be? – Editor.

Thanks to the Madibeng Pulse for this article.