Wetlands are areas of land that are permanently, seasonally or occasionally water logged with fresh, saline, brackish, or marine waters, including both natural and man-made areas that support characteristic biota. Globally, wetlands occupy about 6% of the earth's surface. Kenya's wetlands occupy about 3% to 4%, which is approximately 14,000 kilometers square of land surface and fluctuates up to 6% in the rainy seasons.
Wetlands have several functions and uses which range from ecological, economic, recreational and cultural. They include;
• Maintenance of the water table
The impeded drainage of a wetland allows water to stay in one place long enough to maximize infiltration. This helps in the recharge and discharge of both ground and water resources. A high water table means that in the immediate surroundings of the wetland there is access to water supplies for plants.
• Erosion control and flood control
In their natural condition, wetlands function as a barrier to erosion. The regions downstream of the wetlands would receive full erosive force of storm events, resulting in soil and stream bank degradation. Flood damages in the United States average to $ 2 billion each year causing significant loss of life and property. Wetlands therefore play a role in reducing the frequency and intensity of floods by acting as natural buffers, soaking up and storing significant amount of floodwater. A wetland can typically store about three-acre feet of water, or one million gallons.
• Sediment trap (Acts as a sieve)
Material eroded from the surrounding catchment areas by rivers is sedimented out when the flow of water is slowed upon entering a wetland. Sediment retention prevents downstream resources such as dams, farmlands, rivers and lakes from being silted up. Natural wetlands are so effective at removing pollutants from water that flows through them as the plants and soils absorb much of the excess nutrients in the water hence improving water quality.
• Wetlands as carbon sinks/ storage
Wetlands are one of the most effective ecosystems for carbon storage a critical aspect to climate change and global warming mitigation.
• Wildlife Habitat and centers of biological diversity
Diverse species of mammals, plants, insects, birds, reptiles, and fish rely on wetlands for food, habitat or shelter. Endangered species use or inhabit wetlands at some time in their life. Some species must have a wetland to reproduce. Migrating waterfowl rely on wetlands for resting, eating and breeding areas, leading to increased populations. The appeal of wetlands and diversity of plant and animal life contribute to or support many businesses.
SOCIO- ECONOMIC FUNCTIONS
• Tourism and recreation
Wetlands are often inviting places for recreational activities including hiking, fishing, bird watching, photography and hunting. These activities also contribute towards the country’s foreign exchange. According to studies done, Lake Nakuru for instance gets approximately 300,000 visitors per year bringing US$ 24 million and the estimated value of flamingos in Lake Natron as a flamingo breeding site based on the recreation value of one flamingo per year is US$ 11,819,091. An average price tag of US$33 trillion a year has been established by researchers on these fundamental ecosystem services globally. That is nearly twice the gross national product (GNP) of US$ 18 trillion.
• Plant products
Papyrus and similar plants have been traditionally harvested for necessities such as thatching, mats, baskets while the palms and smaller sized trees are used as structural building materials. For instance communities living around Rivers Nzoia, Yala, Nyando and Sio use papyrus plants materials to make traditional fishing gear. Traditional conical basket traps “esivu” and “Omukono” among the :Luhyia and “Sienya” among the Luo.
• Water supply
Wetland plants have the capacity to take out impurities from the water thus filtering it. Because of this function, it has been possible for rural communities to obtain a pure water supply at no cost.
• Cattle grazing
The marginal parts of wetlands, where the soil is permanently or seasonally moist, have for long been used as grazing areas for livestock especially during the dry season. Grazing and watering of livestock is an important traditional common practice for many communities in Kenya for example the Maasai, Tugens, Turkana, Oromo and Njemps. Traditional livestock rearing is a cultural activity and wetlands are its life support.
Wetlands harbor a substantial population of fish, which have traditionally been caught as an important food item in many parts of Kenya.
• Ceremonial sites
Most communities in Kenya have used wetlands as site for carrying out traditional rites for example circumcision ceremonies among the Bukusu people of Western Kenya use special wetlands sites in River Nzoia basin for these ceremonies. The Kipsigis community of Bomet also carry out circumcision ceremonies on sites at River Sise and the Pokomo of Tana River District.
• Sacred sites
Several wetlands in Kenya are considered as sacred sites where communities make sacrifices for ancestral spirits and spiritual consultations. For example part of Yala Swamp has sites that have traditionally been used for spiritual purposes.
• Sources of traditional food
Wetlands provide traditional vegetables to many riverine communities for example Luhya women collected “enderema” and “lubiliabilia” from the wetlands. The Pokomo used Nyamthaceae species of leaves as vegetables while its potatoes like tuber “Makole” is a source of carbohydrate. Typha domigensis locally known as “Enarau” is a root chewed by the Maasai during the dry periods.