(1)(a) The average percentage water loss per annum in terms of the allocation to the Great Fish River Water Users Association in terms of the allocation is as follows:
|
Annual allocation (Mm3 ) |
Average annual water loss (Mm3) |
Percentage (%) water losses |
|
426 |
106.5 |
25% |
(b) The average percentage water loss per annum in terms of the allocation to the Lower Sundays River Water Users Association in terms of the allocation is as follows:
|
Annual allocation (Mm3 ) |
Average water loss (Mm3) |
Percentage (%) Water Losses |
|
170 |
19 |
11.3% |
(c) The average percentage water loss per annum in terms of the allocation to the Glen Melville Dam in terms of the allocation is as follows:
|
Annual allocation (Mm3 ) |
Average annual water loss (Mm3) |
Percentage (%) Water Losses |
|
110 |
16.5 |
15% |
(d) The average percentage water loss per annum in terms of the allocation to the Lower Fish Permit Area forms part of Greater Fish River Water User Association (GFRWUA), therefore GFRWUA’s water loss also incorporates the Lower Fish Permit Area.
(2)(a)&(b) The short-listed Water Use Efficiency (WUE) interventions which were identified and screened as part of Water Reconciliation Strategy for the Algoa Water Supply System - Orange River Project/Nooitgedacht Low-Level Scheme are as follows:
(b)(i) The lining of the 500 km earth canals in the GFRWUA (Intervention 1) is not recommended to be considered further for the purposes of this study, as the relative cost of water saved of this intervention is far too high. The lining of prioritised “hot spot” canal sections (about 10% of the total 500 km earth canals) is likely a more feasible option as this will potentially lead to substantial volumes of water saved at a relative lower cost. The compulsory removal of overgrown riparian vegetation in and along the GFRWUA earth canals and ongoing maintenance is recommended.
(ii) Improved measuring and monitoring in the GFRWUA and Lower Sundays River Water User Association (LSRWUA) areas of jurisdiction. Although the potential water saved as a result of the implementation of this intervention was not quantified as part of this study, this intervention will lead to improved management and operation of the system and improved compliance to water allocations and water requests made, and will potentially reduce losses in the process.
(iii) Glen Melville Dam obtains its water from the Orange Fish River Scheme. It is an off-channel storage dam. Water is diverted via the Hermanuskraal Weir via the Ecca Tunnel. When Glen Melville Dam is at 50% of Full Supply Capacity (FSC), water is released from Elandsdrift Weir on the OFS into the Great Fish River to fill Glen Melville Dam to 100% of FSC. This operational procedure occurs 2 or 3 times per annum, depending on the water usage. The GFRWUA and the LSRWUA has no inputs to the operations and maintenance of the Lower Fish Permit Area and fall directly under DWS.
(iv) The Lower Fish Permit Area forms part of Greater Fish River Water User Association (GFRWUA) and Lower Sundays River Water User Association (LSRWUA), and therefore the interventions in GRWUA and LSRWUA are applicable in Lower Fish Permit Area.
(3) The Department of Water and Sanitation, through its National Water Resources Infrastructure (NWRI) branch conducts the Water Resources upgrades in respect of infrastructure related to the Great Fish River Water Users Association, Lower Sundays River Water Users Association, Glen Melville Dam and Lower Fish Permit Area. Currently, the rehabilitation of Darlington Dam is the major project that is being planned.