Vol 2 No. 1 March 2004


Honeymoon Bend on the estuary looking north before the rains of the 22-24 January.

Neighbouring communities are equally hard-hit by the drought as they seek pans and streams for cattle


High and dry: St Lucia locals made the most of the drought for boat maintenance.

Brodie’s Crossing in Makakatana Bay had become a dry mudflat

The unique scenario of a closed estuary and no rain flowing into the system

 

Wetlands Wire Page 17

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Drought

SOME RELIEF FROM THE DROUGHT

WW reporter

Welcome, soaking heavy rains fell over the Park for four days from January 21, causing the lake to rise some 30cm, back to last October’s levels.
Mission Rocks (277mm) and Charters (214mm) received the most; good rain also fell at False Bay, Mkhuze, Kosi and Manzengwenya.
The Mphate river is flowing strongly and has raised the level in the narrows significantly - operators in the area say back to 'normal'. The Nyalazi is flowing strongly and spilling (20cm) over the salt water barrier and into southern False Bay. The downside is that it is full of sediments.
The Umfolozi and Umsunduzi river are pumping chocolate brown with lots of debris going out to sea and onto the St Lucia beach - not into the lake.
The Hluhluwe River is flooding west of the Hluhluwe dam but the water bailiff reported the dam only 45.6% full - so we won't see any of that other than local catchment.
The Mzinene river (Sibhicayi) has clear water at the SDI Road but is not flowing to the lake. The uMkhuze is flowing knee-deep (at Denyers Drift - Mantuma) but is unlikely at present to reach the lake.
Pans generally throughout the Park have accumulated water varying from 20 to 80 percent.
This excellent rain has probably given the Park about two months breathing space according to conservation manager Tony Conway, but there is still a whole dry season ahead.
Large volumes of discoloured water were noticed flowing into the narrows and, following a flight, it was confirmed the Umfolozi had breached into the canals in two places: once at the old waterworks intake and a second where the Umfolozi meanders very close to one channel.
The flight also confirmed all the 'lakes' are reconnected, including False Bay.
In Mkhuze game reserve, the Nhlonhlele pan has received a significant quantity of water, and a small group of hippos quickly moved back into the pan.
Communities neighbouring the Park have also benefited from the recent rains.

 

Honeymoon Bend after the recent rains

Tour Operator Kian Barker argues that the mouth should be opened

Fisheries science honours graduate and tour operator Kian Barker argues the mouth should be opened.

Are the managers managing salt levels or biota? Shouldn’t they be looking at how keeping the mouth closed affects the lake’s biodiversity?
A closed river system or lagoon has lower bio-diversity than an estuary; all biological organisms have a limited life span and once gone cannot be re-introduced. The first species to go were the oysters.
If the mouth was open, the back pressure of the normal water level would ensure less water seeped into the estuary. Could it be possible that Mkhuze swamp and adjacent areas have been impacted by the lake’s low level.
Before the man's intervention, the Umfolozi river reached the sea through the lower section of the estuary. The swift flow of the silt-free river flushed out any silt brought by high tide. Obviously when the Umfolozi flowed, the mouth would have been open. Only recently has the Umfolozi stopped flowing! Why has the estuary mouth remained closed?
Many islands with nesting birds have become connected to the mainland allowing access to predators like rats and snakes; very few venture into the water because of crocodiles. So much for protecting bio-diversity.
Migratory fish and invertebrates like crabs and prawns no longer have access to the sea for spawning. The estuary is recognised as a nursery and the current cob ban would not be necessary if the mouth was open! Juvenile fish cannot return and will either die or be eaten. If the current management of the mouth continues, with erratic opening and closing - this could result in dire consequences for many of the 122 fish species.
It may be necessary to introduce the historical amount of freshwater into the lake to mitigate high salinity. Taking water over the ridge from Jozini dam may be a simple solution.
Is the bio-diversity of the Park being maintained by keeping the mouth closed, until rain arrives. Not in my opinion.
We have an international obligation to ensure sound and proper eco-system management - not salinities.