(Environment & Ecology) National Lake Conservation Plan, Wetlands - Functions, Threats, Protection & Impact of Destruction

ENVIRONMENT AND ECOLOGY


National Lake Conservation Plan

The objective of the scheme is to restore and conserve the urban and semi-urban takes of the country degraded due to waste water discharge into the lake and other unique freshwater ecosystems, through an integrated ecosystem approach. Activities covered under NLCP – Prevention of pollution from point sources by intercepting, diverting and treating the pollution loads entering the lake. The interception and diversion works may include sewerage & sewage treatment for the entire lake catchment area.

Streams and Rivers


These are bodies of flowing water moving in one direction. Streams and rivers can be found everywhere-they get their starts at headwaters, which may be springs, snowmelt or even lakes, and then travel all the way to their mouths, usually another water channel or the ocean. The characteristics of a river or stream change during at the mouth. The water is also clearer, has higher oxygen levels, and freshwater fish and heterotrophs can be found there. Towards the middle part of the stream/river, the width increases, as does species diversity – numerous aquatic green plants and algae can be sediments that it has picked up upstream, decreasing the amount of light that can penetrate through the water, Since there is less light, there is less diversity of flora, and because of the lower oxygen levels, fish that require less oxygen, Such as catfish and carp, can be found. Hence Streams and Rivers can be separated into following three zones-

A. Source Zone – It contains headwaters (headwaters streams) and often begins as springs or snowmelt. The water in this zone is cold, clear and carries little sediment or relatively few nutrients. Channels are usually narrow, current is swift and substrate is rocky.

B. Transition Zone – This zone contains wider and lower elevation streams. The streams- here join to form tributaries. The water of this zone is relatively warmer, less clear and carries more sediment or more nutrients. Channels are usually wider, current is slower and substrate begins to accumulate silt.

C. Floodplain Zone – Rivers get fragmented to form distributaries, which empty into oceans at estuaries. The water of this zone is relatively warmer, murky and carries substantially more sediments or more nutrients. Channels are wider, river mouths are also wider, current is relatively slow and substrate becomes silty from deposition of sediments

The nutrient content of river/stream is largely determined by the terrain & vegetation of the area through which it flows. The input of nutrients is through adjacent and overhanging vegetation, weathering of rock, soil erosion and human activities.

Transitional Communities


This type of Biome or ecosystem lay somewhere between freshwater and married ecosystems. The flora and fauna of such ecosystem are adapted to brackish and acidic water. More about these can be studied by dividing them in following two categories-

Wetlands

These are areas of standing water that support aquatic plants. Marshes, swamps, and bogs are all considered wetlands. Plant species adapted to the very moist and humid conditions are called Hydrophytes. These include pond lilies, cattails, sedges, tamarack, and black spruce. Marsh flora also includes such species as cypress and gum. Wetlands have the highest species diversity of all ecosystems. Many species of amphibians, reptiles, birds (such as ducks and waders), and furbearers can be found in the wetlands. Wetlands are not considered freshwater ecosystem as there are some, such as salt marshes, that have high salt concentrations – these support different species of animals, such as shrimp, shellfish, and various grasses.

According to the Ramsar Convention on Wetlands, “Wetlands are areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six meter. “wetlands are highly variable and dynamic : they are water bodies but also include land. They are freshwater. Brackish or saline, inland or coastal, seasonal or permanent, natural or man-made. Wetlands include mangroves, (peat) swamps and marshes, rivers, lakes, floodplains and flooded forests, rice-fields, and even coral reefs. Wetlands are one of the world’s nost important environmental assets, containing a disproportionately high number of plant and animal species compared to other areas of the world. Throughout history they have been integral to human survival and development.

Functions of Wetlands


Presently 75% of the human population lives in former wetlands and surrounding areas. Wetlands have provided people with various products and services since time immemorial. Many of the greatest civilizations of the past developed in areas surrounded by or close to wetlands. Many societies, especially in the developing countries, still depend on wetlands for their survival. For this reason, in many parts of the world wetlands are an essential part of the local culture, religion, folklore and history.

Traditionally, wetlands have been used for agriculture, fishery, as hunting grounds or just for recreation. They have served as as source of fuel, wood and construction material. In more recent days people discovered that this unique habitat type, which provides the transition from water to terrestrial environment, has even more important functions – wetlands shelter a great number of globally endangered plant and animal species, they are recharge, and wetlands mitigate the negative consequences of floods and erosion.

Some of the most important functions of wetlands can be summarized as follows –

1. Biodiversity protection – support a great diversity of species, many of which are unique and rare. Freshwater ecosystems cover only 1% of the Earth’s surface but they hold more than 40% of the world’s species and 12% of all animal species. Although they cover only 0.2% of the ocean floor, coral reefs may contain 25 % of all marine species.

2. Water storage – water is stored in the soil or retained in the surface waters of lakes, marshes, etc.

3. Water filtration – After being slowed by a wetland, water moves around plants, allowing the suspended sediment to drop out and settle to the wetland floor, Nutrients from fertilizer application, manure, leaking septic tanks, and municipal sewage that are dissolved in the water are often absorbed by plant roots and microorganisms in the soil. Other pollutants stick to soil particles.

4. Erosion Control – Wetland vegetation stabilizers shorelines and protects from storms (by slowing down the wind speed, minimizing the effects of waves, water flow and runoff, and they trapping sediments).

5. Wetlands control the floods therebyreducing the need for expensive engineered structures.

6. Groundwater replenishment – part of the water filters into the ground and recharge underground aquifers (groundwater reservoirs).

7. Sediment retention – by slowing down the force of water, encouraging the deposition of sediments carried in the water.

8. Retention of nutrients and other substances – wetland species (especially plants) effectively remove nutrients (mainly nitrogen and phosphorous from agricultural sources but also from human wastes and industrial discharges).

9. Wetlands play at least two critical roles in mitigation the effects of climate change; one in the management of greenhouse gases (especially carbon dioxide, CO2and the other in physically buffering climate change impacts:

  • Wetlands act as significant carbon sinks – the destruction of wetlands will release carbon dioxide, a greenhouse gas.

  • Wetlands will play a further role as the frontline defenders of coastal and inland areas as countries deal with the full effects of climate change : increasing frequency of storms, changing rainfall patterns, rising sea-levels and sea surface temperatures.

10. National transport infrastructure

11. Aesthetic and educational value, support for tourism – the natural beauty of many wetlands makes them ideal locations for recreation, education and tourism.

12. Food for animals – cattle and duck graze on some types of wetlands; wetland vegetation may be used as an addition to forage, etc.

Threats to Wetlands


Wetlands are among the most threatened ecosystem. The life-supporting importance of wetlands was largely unrecognized in the past. People drained, dredged. Dammed and channeled wetlands, eliminated or converted them into dry land or filled them for lakes and water retention areas – changing wetlands into cropland, pasture and subdivisions, mining the underlying resources, ridding insect life, filling in for road beds or flooding them for open water lakes, and using them for dumping grounds for waste and sewage.

Common human activities that cause degradation include the following:

Hydrologic Alterations – A wetland’s characteristics evolve when hydrologic conditions cause the water table to saturate or inundate the soil for a certain amount of time each year. Any change in hydrology can significantly alter the soil chemistry and plant and animal communities. Common hydrologic alterations in wetland areas include:

  • Deposition of fill material for development.

  • Drainage for development, farming, and mosquito control

  • Dredging and stream channelization for navigation, development, and flood control.

  • Diking and damming to form ponds and lakes.

  • Diversion of flow to or from wetlands.

  • Addition of impervious surfaces in the watershed, thereby increasing water and pollutant runoff into wetlands

Pollution Inputs – Although wetlands are capable of absorbing pollutants from the surface water, there is a limit to their capacity to do so. The primary pollutants causing wet-land degradation are sediment, fertilizer, human sewage, animal waste, road salts, pesticides, heavy metals, and selenium.

Pollutants can originate from many sources, including:

  • Runoff from urban, agricultural, silver cultural, and mining areas.

  • Air pollution from cars, factories, and power plants.

  • Old landfills and dumps that leak toxic substances.

  • Marinas, where boats increase turbidity and release pollutants.

Vegetation Damage – Wetland plants are susceptible to degradation if subjected to hydrological changes and pollution inputs. Other activities that can impair wetland vegetation include :

  • Grazing by domestic animals.

  • Introduction of non-native plants that compete with natives.

  • Removal of vegetation for peat mining.

Impact of Wetlands Destruction


The loss or destruction of wetlands can result in :

  • Loss or degradation of wetland habitat and a loss of plant and animal biological diversity

  • Deterioration of wetland water quality.

  • Reduction in water supply and water storage

  • Increased occurrence of algae blooms caused by nutrient overload from land adjacent to a wetland

  • Increased sedimentation, which negatively impacts natural filtration

  • Loss of flood plain land and flood plain protection

  • Reduced range of recreational opportunities

  • Loss of aesthetic values

  • Increased abundance of weeds

  • Loss of species and shifts in species dominance

  • Mosquito problems

  • Changed hydraulic regimes, such as permanent water cover in a wetland with a natural cycle of wet and dry periods

  • Reduction in groundwater recharge, with a negative impact on potential crop production and secure water supplies for humans and livestock

  • Increased soil erosion.

Protection of Wetlands


These amazingly productive and diverse wetlands that stand between upland and open water are vanishing at such a quick rate in some parts of the country that within our lifetime they may just be a memory. It has become inevitable and imperative to protect this ecosystem, otherwise it may cost dearly to human beings.

Following can be some of the measures to protect our wetlands –

  • Not to engage in land use changes or hydrologic modifications.

  • Encourage and support local laws to protect and regulate wetlands.

  • Increase awareness and education about the vitality of wetlands.

  • Avoid mining and construction activities in the vicinity of wetlands

  • Proper implementation of EIA

  • Prohibit the direct and untreated discharge from industries.

  • Afforestation

  • Removal of encroachments


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