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The Fish-Sundays River Canal Scheme comprises a canal and tunnel system which supplies
Orange River water from the Great Fish River valley to the Sundays River valley to
supplement existing water supply in the Eastern Cape. Since 1992 water from the Sundays
River valley has been supplied to Port Elizabeth. It is estimated that up to
200 million m3 of Orange River water could eventually be transferred
to the Port Elizabeth metropolitan area annually.
Orange River water is diverted from the Great Fish River by a weir at Elandsdrift
into an aqueduct which winds approximately 65 km along steep slopes and cuts through the
Bosberg chain between Cookhouse and Somerset East. The main feature of this aqueduct is
the 13,1 km Cookhouse Tunnel through the Bosberg, which was completed in 1978. The
canal discharges into the Little Fish River near Somerset East via a multi-stepped chute,
from where the water flows down the Little Fish River for some 40 km to the De
Mistkraal Weir.
The droughts of the past have created a critical situation in the Darlington
Dam (formerly Lake Mentz) region which, despite being a fertile area, requires an
assured water supply. The serious drought of 1966 and 1967 emphasized the necessity to
commence work on the Skoenmakers Canal with a capacity of 22 m3/s to link
the Great Fish River to Darlington Dam as soon as possible. In view of an expected
increase in irrigation below Darlington Dam and the demand for water in the Port Elizabeth
metropolitan area, it was decided to replace the Wellington Grove pumping station with De
Mistkraal Weir upstream of Wellington Grove and a short section of connecting canal to
the beginning of the Skoenmakers Canal.
With the completion of the De Mistkraal Weir in 1987 the possibility of transferring
water to Darlington Dam at the full design capacity of the Skoenmakers Canal was created.
This water dilutes the salinated water of Darlington Dam and therefore presents an
immediate benefit by improving the water quality for citrus farming in the lower Sundays
River valley. A long-term economic benefit of the weir is the development of irrigation
potential in the lower Sundays River valley. As a result of the developments, a further
16 500 ha can now be utilized for citrus farming.
A further extension of the scheme was launched in 1989 in order to provide water to
Port Elizabeth where supplies were limited due to a severe drought. Water from Darlington
Dam and the Sundays River irrigation canals flows to the Scheepersvlakte Dam, the main
balancing dam for the irrigation scheme. From there water is conveyed by means of a
gravity pipeline to a point on the right bank of the Sundays River where a purification
works has been constructed. From the purification works, the water is pumped to a
balancing dam on the plateau which separates the Port Elizabeth metropolitan area from the
Sundays River, from where it flows to the municipality's existing reservoir at Motherwell.
Apart from the increase in available water to the Port Elizabeth-Uitenhage metropolitan
area, the municipality is less dependent on the Kouga Dam (formerly Paul Sauer Dam). This
is to the advantage of the irrigators in the Gamtoos Government Water Scheme as it will
increase the assurance of supply for irrigation.
The lower Fish River Scheme was initiated in 1985 and completed in 1992. The purpose of
this scheme is to provide sufficient water of a suitable quality to irrigation
developments along the Great Fish River in the vicinity of Committees Drift. The scheme
consists of the Hermanuskraal Weir in the Great Fish River with a tunnel to discharge
flood water and water released from the Orange River into an off-channel storage dam, the
Glen Melville Dam in the Ecca River. The distribution system consists of a canal and
pipelines to the irrigation areas on both sides of the river. The scheme will enable
further irrigation expansion and will ensure that water of an acceptable quality is
supplied.
The scheme also makes provision for Grahamstown's increasing requirements. When the
scheme was started, Grahamstown was already experiencing problems in meeting its growing
demand for water and the Fish River was the obvious source to serve as a supplement. The
scheme ensures that a stable supply of good quality water is available, which can be
linked to the municipal water supply network. The scheme also benefits rural communities
in the Great Fish River catchment (including portions of the former Ciskei) by improving
the quality and availability of water.
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