Natural water sponges, these recharge the ground water; but a one-size-fits-all approach cannot work
Wetlands are land areas that are saturated or flooded with water either permanently or seasonally. They may be located inland or along the coast. They may be natural or man-made.
Natural wetlands include lakes, high altitude wetlands, waterlogged bodies, lagoons, creeks, intertidal mud flats, salt marshes, mangroves and coral reefs. Reservoirs, tanks or ponds, salt pans and aquaculture ponds are human-made wetlands.
“Wetlands are classified depending upon diverse characteristics,” said Muthukarthick of Care Earth Trust, a non-profit engaged in the field of conservation. “It is not just an ecological classification, but based on various factors such as PH value, salinity, location - whether inlands or coastal, stagnant or running and also altitude.
The Ramsar convention defines wetlands as areas flooded with water, where the depth does not exceed six metres.
In Tamil Nadu we have diverse wetlands. We have the Mudumalai wetlands, with tall grasses and they are seasonally flooded. They go dry at some point in the year. Thus wetlands need not have perennial presence of water.
If you take, Kanchipuram, Tiruvallur and Chennai, most of the wetlands are seasonal only. After Ramanathapuram, Kanchipuram has large number of wetlands and most of them are man-made basically.
Natural wetlands are either in forests or at high altitudes. We are currently working on high altitude wetlands above 2000 metres elevation. These are apart from the reservoirs and catchments,” he added.
Wetlands are a critical part of ecosystem. They provide our water requirements and replenish groundwater.
Coastal wetlands have a major role in sustaining the life cycle of many commercial fish. Wetlands absorb pollutants, and sequester carbon.
They help in flood mitigation and afford protection from cyclones and tidal surges. Wetlands are home to more than 100,000 freshwater species. They are essential for bird breeding and migration.
The Convention on Wetlands, called the Ramsar Convention, is an intergovernmental treaty that provides the framework for national action and international cooperation for the conservation and wise use of wetlands and their resources.
India currently has 27 sites designated as Wetlands of International Importance (Ramsar Sites). There are thousands of other wetlands in India besides these wetlands of international importance.
Each type of wetland has its own characteristics. In fact, not all wetlands of the same type are identical. Each has its own unique features.
Ashtamudi wetland and Vembanad-Kol wetland in Kerala and Chilika lake in Orissa are among the Ramsar wetlands of the lagoon type.
Ashtamudi has a thriving fishing industry but population, urban pressures and pollution caused by oil spills from fishing boats and industries located nearby pose threats to the site.
Chilika Lake is a brackish lake, subject to extreme seasonal fluctuations in salinity because of sea water exchange. It faced threat by siltation and sedimentation choking the mouth of the lake.
Rehabilitation efforts by the Chilika Development Authority won it the Ramsar Wetland Conservation Award.
Bhitarkanika mangroves in Orissa include Gahirmatha beach which is the largest known Olive Ridley sea turtle nesting beach, with nearly half a million nesting annually.
The dense coastal forest protects lakhs from cyclones. The mangrove is the source of food, medicines, tannin, fuel wood and honey but population pressures and encroachment tend to jeopardise the equilibrium.
The Sundarbans wetland in West Bengal is within the largest mangrove forest in the world. It protects the hinterland from storms and tidal waves and seepage of saltwater inland. It is also a critical tiger habitat.
Chandratal wetland in Himachal Pradesh supports red listed snow leopard. Overgrazing by nomadic herdsmen has resulted in 65% of the largest catchment area becoming degraded forest.
Other threats include summer trekking, littering of waste and lack of sanitation facilities. Upgrading eco tourism facilities is the priority in wetlands like this.
Deepor Beel in Assam provides a storm water storage basin for Guwahati. It supports globally pretend spot billed pelican and occupant stock. Infestation by water hyacinth, overfishing Kama hunting and pollution from pesticides and fertilizers are the threats to this wetland.
Sasthamkotta lake in Kerala is a source of drinking water. The larva cavaborus eliminates bacteria in the water ensuring high level of purity.
In the case of Loktaklake in Manipur, a dam for hydroelectric power and irrigation has been held responsible for causing the extinction of several native fish species.
Point Calimere in Tamil Nadu is a maze of shallow waters, long sandbars, intertidal flats, intertidal forests, mangrove, lagoons and salt pans.
Illegal collection of firewood and forest produce, spread of Chilean mesquite and expansion of historical salt works have caused increasingly brackish groundwater or causes for concern.
East Kolkata wetlands in West Bengal serve as an urban facility for treating Kolkata's waste water. The treated water is used for pisciculture and agriculture.
Water flows through fish ponds which act as solar reactors. The system has been developed by local people through ages. However unauthorised use of waste plastic channels by industries add metals to canal sludge and threaten edible quality of fish and vegetables.
As pointed out by Space Applications Centre, Ahmedabad, wetlands exhibit enormous diversity according to their genesis, geographical location, water regime and chemistry, dominant species, and soil and sediment characteristics.
Therefore, a one-size fits all approach cannot be adopted for conservation of different wetlands.
Muthukarthick of Care Earth agrees vehemently. “First the wetland has to be studied. For example, if we are studying high altitude wetlands, we need to know if there are peat bogs. These are basically a layer of carbon storage beneath the wetlands.
Second, wherever be the wetland, its connectivity must be looked into. Water inflow and outflow of the wetland is called varathukaal and pokkukaal respectively in Tamil.
In our state, wetlands are mainly managed for irrigation and all these are interconnected. This is called a system of tanks. So when a wetland is to be studied, it means the entire system of tanks needs to be studied so that we may know the functionality of the wetland, if it is lying head stream or tail stream or as a link between a large lake and river.
Thus functionality such as the drainage and ecological factors play an important role.
Third dynamics should be understood. For example, Pulicat lake is connected to the sea. During monsoon, salinity of the water decreases and it increases after the season is over. So water is highly dynamic in nature, as in mangroves. Species are unique to the wetlands and the productivity is very high.
Crustaceans and crabs are well adapted to the changing salinity and there are certain fresh species which breed in fresh water and migrate to sea.
Some breed in the shades of mangroves. Basically they are totally dependent on the dynamics and the balance or else their life cycle would be affected.
Our approach must vary depending upon the wetlands.
Wetlands are largely affected by anthropogenic activities. Our land use patterns have changed and in most cases, wetlands have disconnected inflow or outflow or both.
Our approach should be focused on the land and not the water surface. For example, if there is a sewage inflow into a wetland - it would cause contamination, biological transformation and breeding of invasive species.
We should not interfere with the water or the species. Rather we must focus on sewage flow, which should be prevented.
We have actually tried this in the Narayanapuram, Thazhambur and Pallikarani lakes,” he explained.
Any proposed scheme should take into account the peculiar features and should also involve local stakeholders.
For instance, the mangroves and fisheries in the lower delta of Senegal river nearly disappeared after construction of two dams upstream.
An agency called Diawling National Park was established after which pre-dam flood cycle was restored by setting up sluices and embankments for reflooding, in consultation with local fishermen who had the requisite knowledge.
The government of India has come out Wetlands (Conservation and Management) Rules, 2017, which vest responsibility in State governments for conservation and wise use.
The rules project conversion of wetland for non-wetland uses, encroachment, setting up of any industry, manufacture or disposal of demolition waste and hazardous substances and electronic waste, solid waste dumping come on discharge of untreated wastes and it prevents, any construction of a permanent nature and poaching.
Muthukarthick narrates the experience with the Pallikaranai marshland which is now a restored and rejuvenated marsh, thanks to the work of the Care Earth team in consort with the government of Tamil Nadu.
“We have been studying the Pallikaranai marshland since 2000. It was a no-man’s land by then. Even Koyambedu was like that before the market came up.
We understood the marshland’s importance in flood mitigation in south Chennai. It was absorbing water like a sponge and passing it on to the sea.
We drafted an Adaptive Management Plan for it. The water is not deep there. Shallow, swampy with more mud, there are zones in the marshland, which are not reachable.
And the water is slightly brackish. It is not fresh water. There are some plants and animals in the marshland which are coastal, indicating the salinity in the water.
The Pallikaranai Wetland Conservation Authority was set up focusing on the nature of the marshland, its flood mitigation, saline environment in consideration. This was the approach.
In 2014, we drafted management plans like this for 11 bird sanctuaries in the state. All these are wetlands managed by the forestry and they include saline, brackish and freshwater like Vedanthangal which is fresh water and the Point Calimere which is brackish,” he said.
The rules will apply to wetlands categorised as wetlands of international importance under the Ramsar convention and such as those wetlands as are notified by the central or state governments.
But long term sustenance of wetlands will come only if various government departments work together, says Muthukarthick.
“First the Wetland Authority must study all the wetlands and classify them. They need to work with the departments in charge of various wetlands and come up with management plans for each of the classification.
In case of natural wetlands with greater ecological functionality, we should adapt minimal anthropogenic approach.
So forestry takes over these wetlands, they declare it a No Go zone like we have with Vedanthangal, which is one of the oldest bird sanctuaries.
Public works department manages lakes and water bodies for irrigation. Earlier we had traditional water body management system which was sustainable. But due to anthropogenic pressures, we tend to overexploit resources.
Generally, there must be a check for misuse of wetlands.
Wetland authority can do overall management. They can oversee all the departments if they are following the guidelines as per the classification of wetlands.
If there is a wetland meant for irrigation, then the management plan should be based on water capacity, quantum outflow that can be drained. You cannot completely drain out all the water in a marsh.
In case a tank is leased for fisheries, then it must be ensured that they don’t breed invasive species like the Tilapia, or disturb the ecosystem otherwise.
In case there is tourism, we need to check for the resilience, the threshold of the wetland, if it can support tourism.
If we take our state, mainly wetlands are affected by the anthropogenic pressures. They are either disconnected or contaminated. It must be ensured that water is not stagnant for more than two years.
So there must be a single authority which supervises all the departments if they work according to adaptive management plans without becoming susceptible to exploitation of resources,” he emphasised.
(This article is sponsored by Care Earth Trust as part of an awareness campaign on water conservation)