Zeekoevlei / Rondevlei Rehabilitation Study ... - Southern Waters

Southern Waters Ecological Research and Consulting
Five Point Rehabilitation Action Plan Summary
1. Reduce total annual loading of phosphorus to Zeekoevlei by 60% through:
• dredging of 1.1 million m 3 of accumulated sediments;
• attenuating the seepage of phosphorus-rich water from the adjacent
wastewater treatment plant.
Core programme cost over five years: R 13 000 000.
(parallel reduction of pollution within the Zeekoevlei catchment is being
investigated and costed by a separate study)
2. Reduce total annual loading of phosphorus to Rondevlei by 45% through:
• rehabilitation of the Princess Vlei ecosystem and, in particular, internal
nutrient generation from the sediments and catchment management (30%
total reduction);
• implementation of Best Management Practices within the Rondevlei
catchment (10% total reduction);
• wetland treatment of low flows during the dry season (5 % total reduction).
Core programme cost over five years: R 3 500 000.
3. Implement landuse planning and management policies to reduce the
generation of nutrients at the catchment level, by:
• imposition of non-structural Best Management Practices including
legislation to reverse, modify or relocate identified polluting activities;
• adopt and/or develop Best Management Practices to reduce nutrient
generation by current landuse, or prevent same occurring from planned use;
• apply economic benefit and regulatory mechanisms to encourage catchment
and wetland management directed towards nutrient reduction.
Core programme cost over five years: R 500 000.
4. Monitor and audit water chemistry and biotic response of both vleis to the
implemented rehabilitation (years 3-5).
Core programme cost over five years: R 500 000.
5. Reassess ecosystem health and functioning in terms of:
• Post- vs pre-rehabilitation condition;
• Attainment of water quality targets
• Ecosystem structure, composition, functioning and direction of change,
and determine second phase (year 5+) management needs, inclusive of a
reassessment of the diversion option.
Core programme cost over five years: R 600 000
Zeekoevlei / Rondevlei Rehabilitation Study: Executive Summary
ii