African Travel Solutions News Update “iSimangaliso and drought”
iSimangaliso and drought
Drought is never easy for wildlife and even less so for people and domestic stock. While dry cycles are part of the natural process, increasingly there are questions being asked and a growing awareness of man-induced consequences and climate change and other human-induced impacts on our water resources.
Lake St Lucia levels at Charters Creek on the Western Shores have dropped due to a prolonged drought in the region.
How has iSimangaliso been affected by the drought?
According to the South African Weather Service, iSimangaliso has received below normal summer rainfall and is experiencing extremely dry conditions. Rainfall for July to October 2014 was in the region of 100-200mm compared with 200-300 mm for the same period in 2013. Consequently, water levels in the lakes, rivers, wetlands and pans across the iSimangaliso Wetland Park are very low.
Lake St Lucia is a 36 000ha shallow system with fluctuating depths and varying salinities. Although not unexpected, water levels in Lake St Lucia dropped through the winter of 2014 to just above mean sea level. With little summer rainfall, water levels have dropped further, the water body has shrunk and salinity levels have risen in the northern sections of Lake St Lucia to about 50 parts per thousand (ppt) at Lister’s Point and the Nhlozi Peninsula. Typically sea water ranges between 30 – 35 parts per thousand (ppt). The driver of the natural variability in depth and salinity is the seasonal variation in rainfall.
Droughts are a natural part of the weather patterns in iSimangaliso and drive biodiversity and resilience. It is this very biodiversity that contributed to iSimangaliso’s listing as South Africa’s first World Heritage Site.
“Lake St Lucia is in a better state than during the previous drought which spanned eight years from 2002 to 2010 when there were extremely low water levels, desiccation of large areas of the lake, and extreme hypersalinity. I vividly recall in the last drought walking across the Lake from Catalina Bay to Charters Creek without getting my feet wet,” says Andrew Zaloumis, iSimangaliso CEO. “If we do not get good rains this summer and uMfolozi River water into the system, conditions could well become extremely dire.”
Estuarine scientist Nicolette Forbes says “The fact that Lake St Lucia is in better shape during this drought is largely due to iSimangaliso’s mouth management strategy which has since 2012 allowed the uMfolozi River to follow its natural path into Lake St Lucia. This resulted in increased water levels, initiated the process of restoring estuarine functioning and a normal salinity range over the past 24 months. The uMfolozi is Lake St Lucia’s largest catchment and is the main fresh water source (about 60%) to this estuarine system. Its importance increases during dry years. In addition, the substantial land restoration of the Eastern and Western Shores has also assisted and contributed to the water balance needs of the estuary.”
Greater flamingo are attracted to the Lake in numbers due to the favourable feeding conditions.
The 2015 winter water bird counts provide a good indication of the ecological condition of Lake St Lucia. As a Ramsar Wetland of international importance and UNESCO world heritage site, these counts are important in assisting management to keep its finger on the pulse of the overall condition of the system. The aerial survey completed on the 9th of June counted over 16 500 water birds across the Lake. The dry-down condition suits both the approximately 4200 Greater Flamingo as they stand in shallow water when feeding, and the Greater White Pelicans (approximately 4100). There are also currently over 950 Caspian Terns with about 300 active Caspian Tern nests.
One of Africa’s best game viewing hides, kuMasinga Hide in iSimangaliso’s uMkhuze section is supplied with pumped water to assist in times of low rainfall. The wildlife and bird sightings here are incredible and a huge draw card for tourists.
From a game perspective, pans and water points on the Eastern Shores, Western Shores and uMkhuze are very low or dry. A system of boreholes and water supply points for animals is in place across the Park. As part of our drought preparation these have all been serviced and operationally tested. Auxiliary water systems such as uBhejane Pan on the Western Shores, kuMasinga Hide at uMkhuze and Mfazana Pan on the Eastern Shores have been switched on, resulting in some spectacular game viewing and birding. The situation is being closely monitored and other pumps will be switched on as and when necessary. Further maintenance to the water supply system is underway.
Tourism facilities in the Park all have water including Cape Vidal (above) which has its own auxiliary water system in place.
Lake Sibaya (above) is South Africa’s largest coastal freshwater lake with a historical estuarine past. It is fed almost entirely by groundwater seepage and levels constantly fluctuate in response to varying amounts of groundwater discharge into the lake, seepage loss through the coastal dunes, abstraction and evaporation from the lake surface. Levels are very sensitive to local weather conditions and show direct responses to local rainfall conditions and seasonal cycles. Unsurprisingly the levels are therefore low at the moment and this has accentuated the two sand spits, which are in the process of growing towards one another from the opposite banks. The data from previous studies show these are rapidly growing features with high sedimentation rates which may result in permanent lake segmentation in the long term.
It is also likely that the rates of water abstraction from the lake for human consumption, combined with decreasing rainfall and rapidly increasing commercial plantations, may have exacerbated the observed decreases in lake level. By volume the current abstractions have been evaluated as “small” relative to the large volumes flowing in and out of the lake. However, examination of the water level records show a different story and indicate that the lake may be more vulnerable to abstraction and adjacent stream flow reduction from tree plantations. An iSimangaliso-commissioned study is currently underway to look at the interactions between groundwater levels and lake water levels in response to different water uses.
What has been done to counter the effects of the drought?
“Droughts are part of the natural cycle and management of the World Heritage Site. The restoration and rehabilitation work undertaken in iSimangaliso has gone a long way to improving the resilience of the Park to extreme weather patterns”, says Zaloumis. “However, in the medium to long term managers will increasingly need to develop responses to the conditions that are emerging as a result of changing weather patterns and global warming.”
Management is not driven by the need to respond to the conditions that emerge in response to changing weather patterns. However, The restoration and rehabilitation work undertaken in the iSimangaliso Wetland Park has gone a long way in improving the resilience of the Park to extreme weather patterns.
In the last fourteen years, significant progress has been made in the restoration of degraded habitats. iSimangaliso has effected the removal of over 24 000ha of exotic commercial timber plantations on Lake St Lucia’s Eastern and Western Shores, and implements major community-based, labour-intensive land care programmes with the Department of Environmental Affairs that include Working for Water, Working for Wetlands and Working for Fire, across iSimangaliso. This has provided an important support function to the Lake system and improved its resilience to natural salinity fluctuations.
Progress has also been made in the hydrological restoration of the Lake St Lucia estuarine system by iSimangaliso with funding from the Global Environment Facility (GEF). Based on the most recent scientific work undertaken, the uMfolozi River is being allowed to reconnect with Lake St Lucia and an active monitoring programme has been put in place. For more information on this project, visit www.isimangaliso.com and download the document “Lake St Lucia: Understanding the problem and finding the solution.”