A wetland is a distinct ecosystem that is flooded by water either permanently or seasonally, where oxygen-free processes prevail. The primary factor that distinguishes wetlands from other land forms or water bodies is the characteristic vegetation of aquatic plants, adapted to the unique hydric soil. Wetlands play a number of functions, including water purification, water storage, processing of carbon and other nutrients, stabilization of shorelines, and support of plants and animals. (Ramsar, convention 2010)

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India has over 27000 wetlands of which over 23000 are inland wetlands while around 4000 are coastal wetlands. Wetlands are the ultimate groundwater recharging areas which not only help collection of rainwater and making it available for percolation but also in cleaning the water, and enabling nutrient retention, flood protection and erosion control. Hence, they are also known as the ‘kidneys of landscape’. (Woziniak et al., 2014)

 

The location of wetland in Kamrup(M) District, Assam, its ecological importance and scenic beauty and it maintain reigm of the region. The problems regarding the study is listed below:

1. Shrinkage of  Deepor Beel, Borsola Beel, Silsako Beel is seen.

2. Due to Urbanization the morphological (a particular form, shape, or structure.) change of wetland is massive in short span of time.

3. Municipal and Industrial effluents have become a major threat to the survival of wetlands.

4. Encroachment of the wetland area.

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OBJECTIVES OF THE STUDY AREA

• To investigate the geographical location, distribution and morphology of  wetland in Guwahati metropolitan city, Assam

• To study the impact of human activities on the selected wetlands of study area.

• To suggest preventive and conservative measures in the study area.

 

DATABASE AND METHODOLOGY

For identification of my study area measurement and subsequent change of wetland data has been collected from satellite images from Earth Explorer USGS (U.S. Geological Survey), bhuvan.com (map based content created by ISRO) and relevant secondary information such as:

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1. Base map using TOPOSHEET & Satellite Imagery for 1999, 2009 & 2019 .

2.  Then  NDWI (The Normalized Difference Water Index)  procedure to extract wetland boundary by using  Arc GIS Software [http://www.esri.com/software/arcgis.ArcGIS is a geographic information system (GIS) for working with maps and geographic information maintained by the Environmental Systems Research Institute (Esri)] .

3. After that Digitization of the Wetland Boundary of  different period using Quantum GIS Software (Q GIS or Quantum GIS is an open source geographic information system).

4. Preparation of Supervised & Unsupervised Classification Map to show the LULC (Land Use Land Cover) in and around wetland for different period (i.e 1999, 2009 & 2019) using Arc GIS & Q GIS, which look like this

5. To access the change of wetland for the act of human activities within 500m Buffer ( to specify a distance inward from the boundary of the area features) using Arc GIS .

6. Clipping of the Unsupervised map (ISO cluster) Taking 500m Buffer using Arc GIS.

7. Digitizing wetland area to show Temporal Change  of Wetland for different period using Q and other departmental data. For better understanding of the wetlands and the surrounding areas with GPS(Global Positioning System) information. To know about the economic , socio-cultural, and natural status of the dependent population and prepared a Questionnaire and relevant data has been collected from the field using Random Sampling Technique. And tabulation of the collected data and incorporated them in the study using statistical methods and cartographic techniques.

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Showing Overall Changes in and around Wetland area for different period using Maps, Graphs, and in the form of Table

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Findings

The area of wetlands have declined and other categories such as settlements have increased numerously  from 1999 to 2019 for example : in Deepor Beel the area in hectare was 41.09985, by 2009 it was 36.72 and in 2019 it is 34.56 .  A comparison of the size distribution of wetlands in 1999 with that in 2019 showed. Over the 30 year period, the dominant vegetation cover type shifted from forest to scrub-shrub and emergent to settlement. The study points out the importance of multiple-sampling years for detecting temporal changes in wetlands during shifts in land use.

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The main threats to the wetland are water pollution, decline in fish population, land use pattern and decrease in the number of plant and animal species. The data collected are evident that how human enterferences has affected  the development of both wetland as well as the surrounding in sustainable management.

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Due to improper management of solid waste and absence of sewerage network, this Beels (wetlands)  has become a dumping ground. Quality of  water is very poor. Unchecked growth of algae has taken over the lakesurface. The  areas are also infested by mosquitoes which have made this place prone to vector-borne diseases such as Japanese Encephalitis and Dengue.

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Effective steps are needed for creating awareness among the community on protecting and conserving the Deepor Beel, Borsola Beel and Silsako Beel and its resources.

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There are several interpretations of my findings and calculations of the study area, like the rainfall data , changes of the wetlands individually from 1999-2019.

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For any query regarding this case study contact here -

NAME:             MEGHALI RAI

EMAIL ID:        meghalibororai@gmail.com