Strong team tackles Park's challenges

Parks Chair Mavuso Msimang aims for tangible benefits though investment
Denise Slabbert

Born in KwaZulu-Natal, Mavuso Msimang has a soft spot for the beautiful Greater St Lucia Wetlands Park (GSLWP) area, and says that while the region is blessed with natural abundance, it still remains one of the poorest areas in South Africa.
In his view, the big challenge for the new St Lucia Wetlands Authority is to deliver environmentally responsible and sustainable tourism investments.
He says, `These are twin objectives to reduce unemployment and alleviate poverty while at the same time conserving the spectacular natural beauty and assets of the area.
`This process is well underway and the Authority has consolidated many parcels of land into one park and has created the necessary infrastructure: roads, fencing and a range of tourism facilities,’ he said.

Malaria beaten

He adds that malaria has been controlled and that specific wildlife species have been reintroduced to the park. Most importantly he notes that approximately 60% of the capital spent in the area and the park through the Lubombo SDI and Wetlands Authority has been invested in local people.
He says: `Conservation is about people because it is about how people shape the land and how the land shapes people.’
Msimang adds that communities will continue to benefit through new tourism developments, which will be coming online in the next year, not only as employees but also as partners and service providers to the industry.
`There are 87 expressions of interest in progress in key sites in the park. These involve some of the major players in South Africa,’ he says
Some quarters would criticise the rapid development of the Wetlands, but for Mavuso Msimang and his team, time is of the essence.
He says, `I have undertaken an extensive field-visit to the Wetlands with the Board’s Vice Chair Rob Barbour. From discussions with community members whom we met informally on this visit I sense their impatience and eagerness to see developments in the park.

On fast track

`What this means is that the necessary developments must be fast-tracked, not slowed down. We have to make up for lost time and make things happen in this park – all the time making sure that the natural resources and beauty of the area are conserved and not destroyed.’
He points that that the Wetlands Board has been appointed to safeguard against rampant progress to the detriment of the environment and communities in the region, and stands fully behind the Authority team.
Msimang says, `The foundations have been laid for the Board to take the park forward. The Wetlands Authority team, under the guidance of CEO Andrew Zaloumis, is implementing a well-thought-through and detailed redevelopment plan for the park.
`This plan is based on sound environmental principles and a good understanding of the needs of the people in the area.’

Tangible benefits

He says that the redevelopment plan went through an extensive public consultation process in 2000 and lays down a solid foundation to ensure a balance is reached between conservation and the delivery of tangible benefits to communities.
An updated Integrated Management Plan (IMP) for the Park including a Strategic Environmental Assessment (SEA) will be out for public consultation in the next few months.
Being realistic, Msimang doesn’t deny the many challenges that have faced the development of the Wetlands area, but is decidedly upbeat on the issue.
He says: `Challenges and complications are other words for opportunities. The Authority team has tackled these with vision, innovation and high levels of creativity.
`A new model for conservation is being implemented. It has catapulted the park into the international arena and will be showcased at the upcoming World Parks Congress in September.’

Prof Fred Ellery poses options

The mouth of Lake St Lucia closes naturally at present during the wintertime. This was not always the case since historically the mouth of the Umfolozi River and Lake St Lucia were the same.
Farming on the Umfolozi Floodplain resulted in the separation of the 2 mouths, at which time the mouth of Lake St Lucia started closing seasonally. Its seasonal closure is associated with a rise in the salinity of lake water, which during dry spells can be as high as 3 times the salinity of seawater! This is toxic to freshwater aquatic life, and leads to changes in the ecosystem that are not desirable. The mouth of Lake St Lucia continues to be carefully managed during such spells in order to regulate the exchange of seawater and lake water so that the impact of salinity is minimized. But it is an issue that is still hotly debated as there is little agreement between parties on what constitutes the best management approach. This article attempts to highlight the issues related to management of the mouth of Lake St Lucia.
In order to best understand the issues facing management, one needs to understand the water balance (inputs and outflows of water) of the lake. The lake receives 2 main inputs of water: one is fresh and the other is saline. Freshwater inputs are from 1) rainfall, 2) surface water inflows via inflowing streams such as the Mkuze and Hluhluwe Rivers, and 3) groundwater input from the dunes and wetlands adjacent to Lake St Lucia. Of the freshwater inputs, rainfall and surface water inputs are by far the most important. Saltwater input is due to the influx of water from the Indian Ocean into the lake. Such input occurs daily in the summer, but it is unimportant at this time since there is an abundant supply of freshwater. However, saltwater input is intermittent in the winter due to natural closure of the mouth, but it is important as it is the main source of water during the dry season when freshwater supplies dwindle.

Outputs from the lake include surface water outflow via the narrows into the Indian Ocean and evaporation of water into the atmosphere. Outflow of water into the ocean is the most important means of water loss from the system, although evaporation is the only means of water loss from the system when the mouth of the lake closes.
It is useful to consider the water balance of the lake during summer and winter, in order to appreciate how the lake behaves. During the summertime, freshwater inputs dominate the water balance and the lake remains fresh, despite daily inputs of seawater. The influx of fresh water into the lake in the summer results in the mouth remaining open most of the time. During the wintertime, freshwater inputs diminish and this has 3 important consequences. The first is that marine inputs dominate the inputs of water to the system. The second is that the mouth of the lake into the sea tends to close, as there is insufficient outflow of water from the lake to remove sediment being moved along the coast by longshore drift. Therefore, (thirdly) the water balance is dominated by evaporation.

Evaporation is a process of removal of water from the lake, and is driven by energy from the sun. It results in water loss, but dissolved chemicals remain behind. These chemicals accumulate in proportion to the volume of water lost by evaporation relative to the volume of water present in the lake. Herein lies a big part of the problem. Being an extremely shallow lake, St Lucia is extremely prone to a dramatic increase in salinity over the period of a few months as a consequence of evaporation. For example, if the lake was 10m deep, the removal of 1m of water by evaporation would increase the salinity by roughly 10%. But with a mean depth of something like 2m, the loss of 1m of water by evaporation leads to a doubling of the salinity. Therefore, the rise in salinity per unit depth of water loss by evaporation is primarily dependant upon the depth of water left in the lake, and salinity will rise exponentially as depth decreases due to evaporative water loss.

Salts are toxic to freshwater organisms, such that high salinities result in the death of freshwater organisms unless they can adapt or seek out localized refugia where salinity is low. As salinity rises, freshwater aquatic organisms disappear to be replaced by organisms tolerant of higher salinities. At very high salinities, the life of the lake changes again to reflect prevailing salinity. This sequence of change is particularly evident for birds using the lake for feeding, since they are close to the top of the food chain and are mobile. Thus, under conditions when the lake is fresh, ducks feed on the aquatic plant Potamogeton. As salinity increases, fish invade the lake and pelicans become the dominant bird species inhabiting the lake. As salinity increases further, microscopic plankton form the primary source of food and flamingos dominate the bird fauna.

So, what are the options for management? The mouth of the lake is no longer opened on a regular basis, mainly because of the drastic separation of the Umfolozi River mouth from that of Lake St Lucia, leading to greater variation in salinity in the lake than would be expected naturally. Management therefore feels compelled to intervene. But, how much intervention should there be and what are the implications of such intervention?

There are 3 scenarios to which management may resort. The first is to do nothing at all and let the system experience wildly fluctuating salinities. This is the cheapest option. The second is to repeatedly open the mouth and promote regular exchange of water between lake and sea. Such intervention would require greatest effort in the wintertime, and would require the movement of massive quantities of sediment at great cost. It would result in lake salinities fluctuating between fresh and saline, but salinities would seldom rise much above that of sea water. Thus, salinities would fluctuate over a moderate range. The third scenario would be to do something in-between these two widely divergent courses of action, at intermediate cost and leading to salinity fluctuations between those that would be experienced by no action and continuous action.

What are the critical issues? In my view the main issue confronting managers now is the mean depth of water in the lake. Recall that salinity in the lake increases in proportion to the amount of water lost in relation to volume of water in the lake. With a large volume of water in the lake, the impact of daily water loss is less than it would be for a small volume. We should expect salinity to rise rapidly over the next few weeks in view of the mean water depth being extremely low at present, and it may therefore be opportune to open the mouth of the lake sooner rather than later