Frequently Asked Questions
A wetland is an area in which the soil is wet long enough for anaerobic soil conditions to develop. Anaerobic means that little or no oxygen is present. In a wetland, the oxygenated air that is normally found between solid soil particles is replaced by water which is a poor source of oxygen. Wetlands usually occur in low-energy environments. These are flat areas where water run-off is slow and where wetland vegetation grows well. Wetlands may be partially covered with water, or they may simply have waterlogged soils with no layer of surface water. Wetlands are important components of all river systems. In addition to their significant role in hydrological functioning, they are centres of biodiversity, supporting plants, animals and insects that are specially adapted to take advantage of wetland conditions.
As streams and rivers flow into wetlands, the water spreads out over a large area and the flow-speed is reduced. This is beneficial for several reasons:
- Water sinks into the ground where some of it is stored as a reserve for drier periods
- Fast-flowing storm waters are partly contained, which reduces flood damage.
- The slower water movement aids in the deposit of sediment and pollutants, which may either remain in the wetland indefinitely, or be incorporated into beneficial, naturally occurring compounds
- A diverse range of plant and animal species are adapted to live in wetland conditions.
- They are breeding grounds for many wildlife species - from waterfowl to amphibians to fish.
- Wetland vegetation contributes significantly to water purification and provides food and nesting material for many wildlife species. The mechanisms involved in wetlands are so effective that they are being emulated in artificial wetlands that are constructed for the treatment of domestic and industrial waste.
Source: Mondi Wetlands Project
The following are necessary for wetlands to exist:
- a wetland is found in an area with a gentle gradient or slope,
- the soil in the area is permanently or temporarily saturated,
- anaerobic conditions prevail.
It is sometimes difficult to determine whether an area is a wetland or not. When in the field, there are three things to look for in order to establish the presence of a wetland:
- Soils are anaerobic and there is a temporary saturated zone with orange and black mottles
- The plants are adapted to living in anaerobic conditions – Hydrophytes.
- Amphibious (animals that live on land and in water, e.g: hippo, frog, crocodile, water fowl) animals are present.
According to the proposed classification system from the National Wetland Inventory (2006) commissioned by the Water Research Commission, wetlands are categorized into the following three groups:
Marine Systems encompass ecosystems that are part of the open ocean overlying the continental shelf and/or its associated coastline, but not exceeding a depth of 10 m at low tide - i.e. not extending beyond the shallow photic zone, as described by the South African National Spatial Biodiversity Assessment 2004 (Lombard et al. 2005). Examples of Marine Systems include coral reefs, rocky shores, wave cut platforms and sandy or pebble beaches
Estuaries are partially enclosed ecosystems that are permanently or periodically connected to the ocean, which are influenced by tidal fluctuations and within which ocean water is at least occasionally diluted by fresh water derived from surface or subsurface land drainage. Examples of Estuarine Systems include lagoons, estuarine lakes and river mouths.
Inland systems include all ecosystems that are permanently or periodically inundated or saturated and have no existing connection to the ocean, and are therefore characterised by the complete absence of marine exchange and/or tidal influence. The largest diversity of wetland ecosystems occurs within this group. Inland Systems include a wide range of wetland types ranging from rivers to seeps, pans, floodplains, marshes and peatlands.
Source: National Wetland Inventory, 2006
Wetland formation is influenced by a combination of geology, hydrology and topography. Wetlands form in parts of the catchment where the movement of water is slowed down or obstructed, causing the soils to become temporarily, seasonally or permanently waterlogged.
Geology influences the formation of a wetland in two principal ways:
- A geological obstruction such as erosion-resistant rock may form a dyke or ‘plug’ which resists downward erosion. This results in the landscape behind the plug filling with water and sediments, flattening and forming a wetland.
- Impervious material close to the surface forces groundwater to move close to or onto the soil surface, leading to groundwater discharge. Wetlands that form under these circumstances are referred to as ‘seeps’.
The hydrological cycle is the continuous movement of water, over, above and beneath the earth’s surface. Hydrological characteristics which influence wetland formation are:
- Water sources (precipitation, surface water inflow and ground water inflow).
- Water movement through the wetland (surface flow and subsurface flow).
- How water exits the wetland (evaporation, surface water outflow and groundwater outflow). The ways in which water moves into and out of a wetland are referred to as ‘water transfer mechanisms’.
Topography is the term used to describe the three-dimensional features of the earth’s surface, and specific landforms. The topography of a landscape influences if and where wetlands will form. For example, under the right conditions, wetlands are likely to occur in floodplains, valley bottoms, hillslopes, depressions and coastal flats.
Hydro-geomorphic (HGM) types
As we have seen, wetland formation is influenced by the geology, hydrology and topography of a landscape. A range of hydrogeomorphic types can be distinguished, based on their geomorphic setting (i.e. their position in the landscape and their ‘design’), their sources of water, and characteristics of water flow into and out of the area. There are 6 HGM types supporting inland
wetlands in South Africa.
3. What are the functions of wetlands and why are they so important environmentally, socially and economically?
Flood reduction and stream flow regulation
Wetlands spread out and slow down water moving through the catchment because of:
- the characteristically gentle slopes of wetlands and
- the resistance offered by the dense wetland vegetation.
Also, many wetlands do not have well defined channels that would otherwise speed up the movement of water. By slowing down the movement of water and detaining it for a while wetlands act like sponges which reduce floods and also prolong stream flow during low flow periods. Loss of water to the atmosphere through evaporation and transpiration does, however, reduce the amount of water available to prolong low flows. When wetland vegetation is growing, water is lost from the leaves through transpiration.
However, the water lost into the atmosphere from a vegetated wetland is usually less than would be lost from the surface of an open water area such as a dam. This is because the cover provided by wetland vegetation reduces evaporation from saturated or flooded soil by sheltering it against the sun and wind. When the vegetation dies back, there is no loss of water through transpiration and the dead leaves remain, continuing to shelter the soil. During such times, water loss is most effectively regulated.
Ground water recharge and discharge
Wetlands may have an important influence on the recharge or discharge of groundwater.
Groundwater recharge refers to the movement of surface water down through the soil into the zone in which permeable rocks and overlying soil are saturated. Groundwater discharge, in contrast, refers to the movement of groundwater out into the soil surface. Although poorly understood, it appears that most wetlands are groundwater discharge or throughflow areas. Wetland areas where groundwater is discharging are often referred to as seepage wetlands because they are places where the water seeps slowly out into the soil surface.
Wetlands are natural filters, helping to purify water by trapping pollutants (i.e. sediment, excess nutrients [most importantly nitrogen and phosporus], heavy metals, disease-causing bacteria and viruses and synthesised organic pollutants such as pesticides). Thus, the water leaving a wetland is often purer than the water which enters the wetland. Wetlands are able to purify water effectively because:
- they slow down the flow of water (see flood reduction and streamflow regulation) causing sediment carried in the water to be deposited in the wetland. This also results in the trapping of other pollutants (e.g. phosphorus) which are attached to soil particles;
- surface water is spread out over a wide area, making it easier for exchanges between soil and water;
- there are many different chemical processes taking place in wetlands that remove pollutants from the water. For example, wetlands provide a suitable place for denitrification because anaerobic and aerobic soil zones are found close together. Denitrification is important because it converts nitrates, which could potentially pollute the water, to atmospheric nitrogen which is not a pollution hazard;
- some pollutants such as nitrates (NO3) are taken up by the rapidly growing wetland plants;
- the abundant organic matter in wetland soils provides suitable surfaces for trapping certain pollutants such as heavy metals; and
- wetland micro-organisms help decompose man-made organic pollutants such as pesticides.
Erosion control by wetland vegetation
Wetland vegetation is generally good at controlling erosion by: (1) reducing wave and current energy; (2) binding and stabilizing the soil; and (3) recovering rapidly from flood damage.
Wetlands are usually places where there is much plant growth because of the abundance of water and nutrients in the soil. The plants, in turn, provide food and shelter for animals. There are many different plants and animals that depend on wetlands, and without the habitat that wetlands provide, they would not be able to survive. Several of these species, such as the white-wing flufftail and wattled crane are threatened.
In wetlands, the decomposition of organic matter is slowed down by the anaerobic conditions present in wetlands. This results in wetlands trapping carbon as soil organic matter instead of releasing it into the atmosphere as carbon dioxide. Presently too much carbon dioxide is being released into the atmosphere when fossil fuels (i.e. coal and oil) are used to produce energy, resulting in the global climate being disrupted.
Coal is, in fact, formed from plant material accumulated under wetland conditions in swamps that existed millions of years ago. Thus, instead of destroying wetlands and releasing carbon dioxide into the atmosphere, we should be conserving wetlands which will help reduce carbon dioxide levels in the atmosphere.
Source: Mondi Wetlands Project, 2006
Wetlands, especially temporarily and seasonally waterlogged areas, may provide very valuable grazing-lands for domestic and wild grazers. This is particularly so in the early growing season and during droughts when grazing reserves are low in the surrounding veld (rangeland) but the wetlands continue to produce a lot of grazing. Permanently wet marsh areas tend to have a lower grazing value because most mature marsh plants are unpalatable, and the excessive wetness may stop animals getting into the wetland. Utilization needs to be sustainable if the wetland is to maintain its value for grazing. As with dry land pastures, wetlands are only able to sustain a certain amount of grazing. Particular care is required in wetlands where the erosion hazard is high.
Fibre for construction and handcraft production
Wetland plants have been used for thousands of years, providing valued material for products such as mats, baskets and paper (produced from papyrus, which is a sedge).There are several plant species which are suitable and are used extensively for making handcrafts in South Africa, such as the rush Juncus krausii (iNcema), and the sedges Cyperus latifolius (Ikhwane) and C.textilis (iMisis). The common reed (Phragmites australis) is used for construction purposes. Some wetland plants are also collected for medicines.
Handcraft production from harvested wetland plants has many benefits as a development option in poor communities: it makes use of local traditional skills; it has the potential for immediate cash returns and, by increasing the financial benefits to the local people, it increases the incentive not to destroy the wetland, thereby contributing to the conservation of natural habitats. However, harvesting needs to be sensitive to the functioning of the wetland.
Although the value of wetlands for fisheries varies greatly, floodplain wetlands (e.g. Pongola River Flats) and estuaries (e.g. Kosi Bay) are typically valuable in the production of fish for human consumption. Many sea fishes in South Africa spend some of the early phases of their life cycle in estuaries, and freshwater fishes such as barbel also use wetlands.
Hunting waterfowl and other wildlife
Some wetlands are important places where waterfowl (including ducks and snipe) and other wildlife such as reedbuck can be hunted. In the USA a great many people take part in the recreational hunting of waterfowl which depend on wetlands for breeding and food. In fact, duck hunters have helped to conserve many wetlands. The hunters recognize the importance of wetlands for ducks and are willing to pay to make sure that the wetlands remain in their natural functioning condition.
Valuable land for cultivation
Wetland soils are potentially productive. However, the anaerobic conditions associated with wetlands exclude most commonly grown crops except for those specially adapted, such as madumbes (Colocasia esculenta) and rice. Thus, wetlands are often drained so that plants not adapted to the waterlogged conditions can be grown. This has important environmental impacts, requiring that the cultivation of wetlands be well controlled. Some wetlands are used for timber production but because of the impact that trees have on wetland benefits, strict controls are required.
A valuable source of water
Because water is stored in wetlands, they provide sites for the supply of water for
domestic and livestock use, as well as for irrigation. The storage capacities of
wetlands are sometimes increased through damming. However, this often has
important negative effects on other benefits.
Economically efficient wastewater treatment
Wetlands purify water. Natural wetlands provide this service to society “free of charge”. Thus, natural wetlands are sometimes purposefully used to treat polluted water and many artificial wetlands area being created for wastewater treatment. When using a wetland to treat wastewater, several factors need to be considered to assess how effectively a wetland will purify water:
- the pollutant, the wetland soil, flow patterns in the wetland, the size of the wetland, and the climate affecting the wetland, which all determine the capacity of the wetland for purifying the wastewater. For example, more pollutants are likely to be trapped in a wetland where the flow is spread out across all of the wetland than in a wetland where a channel concentrates flow in only part of the wetland. If the pollutants are heavy metals then a wetland with soils rich in organic matter is likely to be more efficient at trapping heavy metals than a wetland with soils poor in organic matter; and
- the amount of pollutant relative to the capacity of the wetland. The capacity of the wetland is obviously limited, and if the amount of pollutant greatly exceeds the capacity, the wetland will not effectively purify the water. The impacts of pollutants on the wetland also need to be considered.
Aesthetics (beauty) and nature appreciation
Although wetlands which fringe estuaries, rivers and streams are next to open water, most natural inland wetland have fairly limited open water associated with them. Thus, they are generally not good sites for water sports. However, wetlands are good places to see birds. Large numbers of birds are often attracted to wetlands, with many of these birds found only in wetlands. Wetlands also add to the diversity and beauty of the landscape. Wetlands have a diverse range of colours and textures and some very attractive flowers such as those of vlei lilies (Crinum spp.) and ground orchids.
Source: Mondi Wetlands Project, 2006
A peatland, or mire, is a wetland that contains a type of soil called peat. Peat enhances the normal wetland functions, making peatlands particularly efficient in water storage and highly effective as filters. Peatland soils are anaerobic and acidic.
Peatlands require specific conditions to form:
- Permanent water - either from high rainfall or a raised water table or both;
- Low-energy environments with poor drainage;
- Annual vegetation growth where the growth rate is higher than the decomposition rate.
Peatlands form originally either by the filling in of shallow water bodies by peat and organic matter, or they form in areas where forests, grasslands, rocky areas or river floodplains previously existed. These changes occur because of climatic or tectonic processes. Local climatic conditions and geology greatly influence the formation of peatlands. For example, high rainfall and high nutrient levels result in greater vegetation growth, which enhances peat production.
More than 50% of the world's wetlands are peatlands, and most are concentrated in the northern hemisphere. Southern hemisphere peatlands are generally small (under a hundred hectares), sparsely distributed and relatively shallow. In the northern hemisphere with its considerably higher rainfall, peatlands occur over large areas (hundreds of thousands of hectares) and have an average thickness of 1.5m. Less than 1% of the world's peatlands are found in Southern African and South America.
Healthy, undisturbed peatlands remain active and effective no matter how old they are for as long as conditions are favourable. There are several types of peatlands, which are classified according to vegetation typeand the source of water. The two main peatland types are fens and bogs.
A bog is a peatland that is fed from rain water only. It is a perched wetland, where the groundwater has no contact with the wetland. Some bogs support forests, but they are generally nutrient-poor.
A fen is a peatland that is fed from both rainwater and groundwater. The water table is bowed. It arches upwards into the peatland, adding mineral elements to the peatland from rocks underground. The rich swamp forests of Maputaland occur in fens.
In South Africa, peatlands are rare and unique. They occur in inter-river valleys on the Highveld and escarpment, and inter-dune and inter-river valleys along the coast. About 15% of the wetlands along the KwaZulu-Natal coastal plain contain peat. Most of the peatlands in Maputaland and the Highveld are fens.
Peatlands support typical wetland wildlife. Where open water exists, safe nesting grounds are provided for waterfowl. Fauna includes species such as hippos and crocodiles, as well as nematodes, amphibians and a great diversity of bacteria.
The thickest peatland in South Africa is the Mfabeni Swamp in St Lucia. It is 10m thick and about 45 000 years old.
The thickest recorded peatland in the world is the Grande Pile in Haute Saôre, France. It reaches down 30m.
Source: Mondi Wetlands Project, 2006
Peatlands as archives
Peatlands are palaeo-environmental archives, since pollen grains are preserved in peats. These pollen grains can provide information what past landscapes and past climates were like.
Peatlands as carbon sinks
Peatlands are organic sinks. Although peatlands cover only 3% of the earth’s surface, they store 30% of ‘land’ carbon. Disturbance of peatlands can lead to the release of Carbon and Methane from peatlands. These are ‘greenhouse gases’ which are believed to contribute to global warming.
Peatlands store freshwater
Peatlands store about 20% of all the world’s freshwater resources. One cubic metre of peat holds just under a cubic metre of water. They can act as a ‘sponge’ regulating the hydrology of downstream ecosystems and buffering against floods and drought.
Peat is a non-renewable resource
Peat is not regarded as a renewable resource as it forms over very long periods of time. A peatland can only return to its original state if it is left undisturbed for hundreds or even thousands of years. It is extremely difficult to rehabilitate extensively mined peatlands back to a health state.
Some relevant legislation
Peat extraction is regulated under CARA and NEMA and the NWA. A National Peat Working Group comprising of the three Departments (DWEA, DoA and DEAT) is responsible for the evaluation of applications for peat extraction. Peat is not considered a mineral in terms of the Mineral and Petroleum Resources Development Act 28 of 2002. An Environmental Impact Assessment (EIA) must be carried out before peat extraction will be granted a licence.
Source: Mondi Wetlands Project, 2006
Over-grazing by livestock
Grazing may have both positive and negative effects on the indirect benefits of wetlands. In wetlands which have some areas grazed short and other areas left tall, the diversity of habitats is increased. In wetlands which are grazed short completely, the diversity of habitats is decreased.
Heavy grazing may cause valuable grazing species to be replaced by less productive and/or palatable species. Some wetlands erode easily when disturbed by trampling and grazing. The most easily eroded are those wetlands with unstable soil and where water flowing diffusely across the wetland concentrates into a channel. In these situations erosion can cause the channel to cut up into the wetland and dry it out, destroying most of its value. Thus, grazing pressure should not be too high and cattle need to be kept away from these flow concentration areas.
Soil erosion and drainage caused from peat mining
Because so little is known about peatlands, the detrimental effects of any disturbance are immeasurable and cannot be accurately predicted until we learn more about our peatlands.
Peat extraction: between 30% and 60% of Highveld peatlands (about 6% of known South African peatlands) are being or have been exploited for peat. This affects local biodiversity negatively, and drastically reduces the water storage and filtering properties of the wetland. In South Africa, peat extraction is severely damaging to our scarce water resources, and impacts on the wetland's flood control function.
Peat extraction in South African peatlands cannot be sustained ecologically or economically. The cost of water and water quality is immeasurable. South Africa is already forced to import water. Where peatlands have been severely impacted, we have seen a decline in flood control, water quality and biodiversity. There is no justification for damaging local hydrology and reducing water quality.
Peat mining is destructive wherever it occurs but if absolutely necessary, South Africa can import peat from countries with large peat resources, where peat extraction is not as ecologically damaging. This could be justifiable for purposes such as pollution cleanups and medicinal uses. The main users of locally extracted peat, the mushroom and nursery industries, produce non-necessities for a small component of our population, yet they are exploiting peatlands that area valuable to all. Both these industries can substitute peat with other materials. There are 20 000 people in the nursery industry who work with peat, but none of these jobs are entirely dependent on peat. It is highly unlikely that jobs in this industry will be lost if local peat becomes unavailable.
Continued local peat extraction will result in phenomenally increased environmental costs.
Excess nutrients from agricultural fertilisers and pesticides
Excess nutrients stimulate mass growth of hydrophytes, which in turn clog the system and decrease oxygen levels in the water. The mass of plant material provides habitat for bacteria to grow and thrive and nutrients from dead and rotting material add to the cycle and eventually eutrophication occurs, where all the oxygen in the water is used up and little life can be supported in the system.
The drainage of wetlands for agriculture or development - the functions of the wetland become obsolete, decreasing the bio-diversity:
When wetlands are converted to cropland most of the indirect benefits of the wetland are lost, especially if the wetland is drained. Drained wetlands are less effective at regulating stream flow and purifying water because the drainage channels speed up the movement of water through the wetland. Drainage increases the danger of erosion by concentrating water flow and thus increasing the erosive power of the water.
Also, the hydrological changes resulting from drainage have negative effects on the soil (e.g. reduced soil organic matter and moisture levels and, sometimes, increased risk of underground fires and increased acidity due to the oxidation of sulphides to produce sulphuric acid). The soil is disturbed when crops are planted, and crops do not bind or cover the soils as well as the natural wetland vegetation. Thus, erosion is controlled less effectively, which may be a very serious problem in areas with high erosion hazards. Adding fertiliser and pesticides (which may leach into the river system) further reduces the effectiveness of the wetland in purifying water.
The impact of cultivation can be reduced if practices characteristic of low input/traditional cultivation are followed.
Pollution from mismanaged sewerage works, dumping and litter from storm water drains
For example water hyacinth (Eichhornia crassipes). Water hyacinth is usually free-floating with bunches of long, feathery, hanging roots. It is the most damaging aquatic weed in South Africa. It occurs in dense mats in waterways and in dams, obstructing flow, increasing siltation and evapotranspiration. It also disrupts the aquatic environment by reducing light penetration and the large amounts of rotting plant material use up the oxygen, eventually resulting in eutrophication (water enrichment resulting in the decrease of dissolved oxygen and the death of aquatic life) in dams and ponds.
Any aquatic plant can become a nuisance and it is often indicative of a silt build-up or excessive amounts of nutrient being available- should this situation arise it is advisable to determine the cause. Fertiliser being washed off surrounding lands, washings from a dairy or sewerage can create problems. However if there is no apparent source of nutrients, or if the situation cannot be altered, then it may be possible to control the weed. Dense mats of floating weeds have an
enormous capacity for vegetative reproduction and the effects on the aquatic environment include blocking out light, reducing oxygen, increasing evapotranspiration and providing habitat for mosquito breeding and some vectors of bilharzia.
Timber plantations have a high impact on the water storage function of wetlands because a lot of water is lost by the trees through transpiration. Some trees (e.g. gum trees) use more water than other trees (e.g. poplars, which lose their leaves in winter). Trees also have a strong negative effect on the habitat value of wetlands. Under increased shading beneath the trees, the vigour of indigenous plants which are not adapted to these conditions is reduced and they are often out-competed by alien invasive plants. In South Africa there is a law (Section 75 of the Forestry Act No 122 of 1986) which prevents the planting up of wetlands to timber.
Poor urban storm water management
The flood storage potential of wetlands is especially important near urban areas. Urban development with it’s tremendous increase in impervious surfaces (roads, driveways, parking lots, and buildings) coupled with the loss of wetlands, causes more water to run off the land during and immediately after rainstorms. This raises the flood peaks, increases the frequency of destructive floods, and escalates the cost of damages.
This is easy to see from the recent tragedies along the Jukskei River in Gauteng, and below the Hartebeespoort Dam in the North West Province. Gauteng is a watershed for rivers that run to all points of the compass, and most notably, it is where the headwaters of the Crocodile River rise. In the past, the grasslands and wetlands of Gauteng acted as sponges, absorbing water and dampening peak flows. These days, most of Gauteng is paved so water hardly soaks into the ground anymore. Instead it runs off in great volumes and at great speeds into storm water drains and then into rivers.
To exacerbate matters, there is little natural grass or indigenous tree cover along the riparian areas of our rivers. In turn the river banks become highly unstable. As a result storm water slices off great chunks of river bank as it ploughs through, creating large, straight channels that encourage even greater water speeds, which drown people and livestock, carry off homes and flush away bridges.
Source: Mondi Wetlands Project., 2006
Wetland destruction is detrimental to our water supply because wetlands are crucial to a healthy catchment in any river system. One of the main functions of wetlands is to purify water by removing excess nutrients, trapping litter and debris and causing the deposition of effluent on the wetland bed. This ensures cleaner water exits the wetland. If a wetland is destroyed or modified (for example , the reeds are removed and drains are dug), the basic functions of the wetland are then compromised, thus compromising the quality of the water that exits the wetland.
The word “Wetland” is a family name given to many different types of wetland. They range from springs, seeps, mires and bogs in the upper catchment, to midland marshes and floodplains, to coastal lakes, mangrove swamps and estuaries at the bottom of the catchment. All these are connected by yet another wetland type - river banks. Few people understand what lies at the heart of the need for wetland conservation – real economic worth. These wetland systems have an enormous monetary value and make huge, direct contributions to national economies and the creation of wealth. Lest anyone think this is an exaggeration, Nature – one of the most respected scientific journals in the world – reported recently that, worldwide, wetlands are worth some $4.0 trillion (R25-trillion) a year!
Why are they so valuable? Because their primary task is to manage water. At current supply and demand it is estimated that South Africa’s water resources will be fully utilized by 2030. Without sufficient water we cannot grow enough crops, support the growth of industry and mining, or develop a growing tourism industry. Our economy is therefore totally dependent on a continual supply of water of sufficient quality and quantity. Wetlands protect water. Acting like giant sponges, they hold back water during floods and release it during dry periods. In a dry country like South Africa, this is crucial. By regulating water flows during floods, wetlands reduce flood damage and help prevent soil erosion. Wetlands recharge ground water sources, and also remove pollutants from the water. Being natural filters, they help to purify water by trapping these pollutants, which include sediment, heavy metals, disease-causing bacteria and viruses. Some wetlands, such as estuaries, serve as important breeding grounds for oceanic fish. Many wetlands can be used as grazing areas, if done on a sustainable basis. They perform all these vital functions for free - and as a bonus, wetlands conserve biodiversity. Yet wetlands are one of the most threatened habitats in the world today. It is estimated that over 50% of South Africa’s wetlands have already been destroyed. The main culprits have been the drainage of wetlands for crops and pastures, poorly managed burning and grazing which has resulted in head cut and donga erosion, the planting of alien trees in wetlands, mining, pollution and urban development. All these impacts alter the water flow and water quality which kills the wetland. Continued wetlands destruction will result in less pure water, less reliable water supplies, increased severe flooding, a lower agricultural productivity, and more endangered species.
So wetlands are not just a pretty face. They are crucial to our national economy, and when the real value of their free ‘service’ is calculated, one realises that wetlands earn South Africa millions of rands a year. We simply cannot afford to lose one more wetland!
Source: Mondi Wetlands Project, 2006
De-mystifying the Ramsar Convention
By Michelle Nel
South Africa was one of the first signatories to sign the Ramsar Convention which protects wetlands. But what is this Convention? How does it work? What wetland work can you do to help SA achieve its obligations and how can we all pressure the government into fulfilling its obligations to Ramsar?
What is the Ramsar Convention?
The full name is the 'Convention on Wetlands of International Importance Especially as Waterfowl Habitat' and it was adopted in Ramsar, Iran in 1971 (coming into force in 1975). As of June 1999, there were 116 Contracting Parties (or countries) in all parts of the world.
Approximately 980 wetlands (over 70 million hectares) have been designated as Ramsar Sites. Ramsar is the only environmental treaty dealing with a particular ecosystem. Ramsar is also the first of the modern, global, intergovernmental treaties on conservation.
How did it begin?
In 1971, the representatives of 18 countries went to the small town of Ramsar in Iran to put their signatures to a Convention on Wetlands, or the Ramsar Convention.
How does it operate?
The Ramsar Convention promotes the intrinsic functions and services wetlands provide for human populations, and encourages their wise use. Ramsar’s guidelines emphasise the benefits and values of wetlands for: sediment and erosion control; flood control; maintenance of water quality and abatement of pollution; maintenance of surface and underground water supply; support for fisheries, grazing and agriculture; outdoor recreation and education; and climate stability Ramsar aims to provide the tools for involving local people and stakeholders in the development of management plans for wetlands whether these are recognised under the Convention or not.
UNESCO serves as Depositary for the Convention, but its administration has been entrusted to a secretariat known as the Ramsar Bureau at IUCN which co-ordinates day to-day activities. The conference of the Contracting Parties (those countries belonging to the Convention) meets every three years to further the application of the Convention. The Standing Committee, including representatives of the world's seven regions, meets annually. The Scientific and Technical Review Panel provides guidance on key issues.
Participating countries are encouraged to establish national wetland committees made up of government and non-governmental bodies. The list of Wetlands of International Importance is also an important tool of the Convention. Ramsar sites facing problems can receive technical assistance. Small grants are available for conservation and wise-use projects (although this is limited to one site per country). The Convention also publishes technical and educational materials including a newsletter.
Contact: Ramsar Convention Bureau
Tel+41-22-999 0710, fax 9990169
Ramsar Web site: www.ramsar.org
How does SA benefit from being a member?
For over 30 years the Convention has served as an essential mechanism towardsheightening awareness of wetlands. It has also protected specific wetlands. Forexample, a project to mine heavy metals from the dunes at the St Lucia Ramsarsite was stopped due to local and international pressure (two of South Africa’s 16 Ramsar sites are on private land and the rest are in reserves).
In global terms the Convention has served to draw attention to wetlands. At a regional level it has served to cement treaties and agreements on wetland use and management.
At a country level it has helped to draw attention to important wetlands, improve protection and contributed to restoration. One of its greatest strengths is its simplicity.
What are the SA government’s obligations?
The Convention sets out five primary obligations for signatories:
To designate and promote the conservation of at least one Ramsar Site
(although members are encouraged to designate all of their sites that are
internationally important) to co-operate internationally on transboundary
wetlands, shared wetland species and development aid for wetland projects
around the country
- To formulate and implement planning for the wise use of all wetlands in their territory (not just Ramsar sites)
- To establish conservation areas and promote training in wetland management and research
- Consult with other contracting parties about the implementation of the Convention
- To contribute to the Convention budget (SA pays R30 000 per year in membership fees)
Future challenges for the Ramsar Convention
Perhaps the most important goal is to increase the total number and area of Ramsar sites around the world (it is likely that there are at least another 1 000 sites of international importance comprising at least another 100 million hectares).
- Ensure that Ramsar sites are representative of all major ecosystems.
- Improve the management of wetland sites on private land.
- Make people part of the solution, not just government workers.
- Adopt a catchment approach to wetland management
- Address the emerging crisis in freshwater resources and biodiversity
- Strengthen international co-ordination to improve the conservation and wise use of wetlands.
Worldwide, some 50 000 people die daily due to waterborne and water related diseases, while 80% of all diseases worldwide are attributable to drinking water quality, says David Lindley, national coordinator of the Mondi Wetlands Project.
“People don’t realise how dangerous dirty water is,” he says. “For example, Environmentek’s Cape Water Programme involved 12 rural communities in the Western Cape and found that 33% of people did not disinfect their drinking water, even though almost two thirds of samples failed the SABS Drinking Water Maximum Allowable Limits.”
At least 650 South Africans die of diarrhoea every day. The Water Research Commission says that short term direct costs, such as hospitalisation and treatment of diarrhoea patients are around R5 billion a year. Total annual costs are estimated at R15 billion.
These costs can only get higher if we consider South Africa’s rising population, lack of services and falling health budget. For example, the rivers around Gauteng are rapidly deteriorating and the water has become a microbiological cesspool. Samples taken by Urban Green File magazine at Bruma Lake, Gillooly’s Farm, Alexandra and Northern Wastewater Treatment Works showed faecal coliforms per 100ml as 450 000, 450 000, 3 million and 30 000 respectively. (The target is 130 maximum). E coli per 100 ml were 60 000, 25 000, 3 million and 30 000 respectively. (The ideal is a maximum of 130).
The Northern Sewage Works’ discharge water after processing has had E. coli counts as high as 69 000 per 100 ml. Yet water is considered suitable for swimming with less than 125 E. coli per 100 ml. At one stage, eight sewage works in Gauteng were allowing raw waste into rivers. Sewerage can carry cholera, typhoid, hepatitis and dysentery, all of which start with acute diarrhoea.
Johannesburg children have even contracted dangerous shigella dysentery. Fishermen, canoeists and swimmers often seek recreation in waterways that posed a dire threat to health. “Contaminated rivers do not only affect people who wash or play in them,” warns David Lindley. “Diseases which start with swimmers can quickly spread through a community.” When contaminated water is sprayed on crops, food becomes unsafe. People who drink river water work in the homes of people who drink tap water. The bacteria can be spread. There is a cycle and everyone is at risk, no matter who they are.
Wetlands to the rescue
Luckily wetlands provide a free service in purifying water, a service we would do well to utilize more effectively if we are to contain the rapid deterioration of water, David Lindley points out. If we lost the services of wetlands, we would have to replace them with artificial wetlands and extra water treatment plants at great cost.
In America, the important role that wetlands play in improving the water quality is recognised by protecting wetlands in the Clean Water Act. In both USA and Europe, extensive wetland areas are being restored and conserved as part of broad integrated plans to maintain good catchment quality.
That natural wetlands improve water quality should be taken into consideration by all private and government agencies concerned with land-use management and planning, says South African wetland expert George Begg.
Every effort should be made to preserve the few wetlands remaining in many agricultural and urban areas. Wetlands behave as nitrogen and phosphorous ‘traps’. Removal efficiencies of up to 90% of nitrogen have been reported for some wetlands. Submerged soils, high in organic matter are phosphorous ’sinks’. Various studies have been made in wetland ecosystems of the changes in concentrations of other dissolved compounds in water such as sodium, chloride, calcium, magnesium and potassium. Their fate is less well understood. There is some evidence that wetlands remove heavy metals - from 15% to 32%. It is important to note that wetlands store certain components that they remove but the disturbance of wetlands leads to their release back into the system. Water-borne pathogens are not stored but destroyed by wetlands.
An efficiency of 86% coliform bacteria was achieved in the USA. “Conserving and improving what wetlands we have left, as well as restoring defunct wetlands, are urgent priorities if we are to address South Africa’s deteriorating water quality,” says David Lindley. At present in Gauteng, the water drawn by Rand Water is from the Vaal Dam and not the barrage and this water is in good condition so purification costs are low (they would increase if there were more bacteria in the water) say Marc de Fontaine, Catchment Coordinator for the Vaal Barrage at Rand Water.
There are however problems with the Rietspruit, Blesbokspruit and Klip Rivers but these drain into the Vaal Barrage below the dam. Purified drinking water is safe because it is disinfected but danger lurks for people using river water - either for drinking, washing or swimming, he warns. The Klip River already has many wetlands on it which are helping to keep the water clean, Marc de Fontaine comments. Water quality would be a lot worse if the wetlands were absent.
However, there is a limit to how much pollution wetlands can remove from water. “Artificial wetlands would be a good idea but they would not function straight away,” he says. “People using river water need to be educated.” Because faecal contamination is a diffuse source it is difficult to point fingers but some of the culprits include informal settlements without sanitation and municipal water treatment works that do not purify water properly.
Hope in artificial wetlands
While conserving and restoring natural wetlands is Mondi Wetlands Project’s main function (and also because nature does a more efficient job than mankind), artificial wetlands have their place as well in water purification,” says David Lindley.
Constructed wetlands are designed, built and operated to emulate the natural functions of wetlands. Constructed wetlands have advantages over other means of treating wastewater because they require little energy, chemical input or maintenance. The constructed wetland at Mount Grace Hotel, for example, is both functional and aesthetically pleasing. Its operating costs are also low. Wetland are being actively investigated on a number of South African mines to provide a self-maintaining long term (including after mine closure) solution to the treatment of acid drainages and leachates. However, the technology is new and still being perfected. Nursery owners in America and Europe were facing punitive measures if they did not reduce contamination of their water supplies and many turned to artificial wetlands to purify water so they could avoid using chlorine and other harmful chemicals. A local nursery owner is now also using researchers at Potchefstroom University to help him construct an artificial wetland.
The CSIR Water Technology branch as “Wetland Ecological Technologies (WET)”, a range of artificial wetland installations. Wetlands can be used as rural schools, police stations, game lodges, caravan parks or in communities without sewerage systems. Standard wetland designs are also available for smaller installations, from 25 to 100 people. A DIY installation is also available as modular design kits, in four-person modules which can handle the waste of up to 12 people. There are currently more than 40 artificial wetland sewage systems operating in South Africa including 12 in the Kruger National Park, other game reserves and in small communities (for information, contact CSIR on (012) 841 3580).
For further information on the Mondi Wetlands Project, contact David Lindley on 083 – 222 9155 or e-mail: firstname.lastname@example.org
Source: Mondi Wetlands Project, 2006
The primary objective of wetland delineation is usually to identify the outer edge of the temporary zone of a wetland (see diagram below). The outer edge of the temporary zone marks the boundary between the wetland and the adjacent terrestrial zone. There are 4 specific indicators used in delineation:
- Terrain Unit Indicator
- Soil Form Indicator
- Soil Wetness Indicator
- Vegetation Indicator
The soil wetness indicator is the most important when making a delineation decision, with the other three indicators used in a confirmatory role.
The point where the wetland indicators are no longer present is regarded as the edge of a wetland.
When delineating a wetland (finding its extent), you start where the permanent water ends and take soil samples with a soil auger at equal intervals along a transect perpendicular to the water flow.
The centre of the wetland is characterised by dark grey, clay soil. This is because of the lack of oxygen, which is required for the oxidation (rust) of the minerals like iron in the soil which gives dry-land soils their red-brown colour. This is the permanently wet zone.
Towards the edges the seasonally wet zone is encountered. This zone is characterized by grey soils, but there are lots of orange and black mottles evident in the soil. This shows that for some time of the year the soil is exposed to the air and oxidation of the minerals occurs. The soil in the temporarily wet zone tends to be lighter and more brown, with few mottles, and the non-wetland, or dry-land soils are the characteristic red-brown colour.
There should be no agricultural, forestry or development activities in any of the previously named zones in order for a wetland to be properly conserved. There should be a buffer zone between the edge of the temporarily wet zone and any development.
A transect in a wetland showing areas with different water regimes
Source: Wetlands and People, Sharenet booklet
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