The Aravalli range is one of the oldest mountain ranges in the world. Many lakes are sustained by the streams generated from the Aravalli range. In the last few years, hill systems are facing changes affecting the catchment of water bodies. Many waterbodies that were earlier able to provide water in peak summers are now dried up before the summer. The study aims to analyse land use land cover change in the Aravalli range on Sambhar Lake. Sambhar Lake is the largest inland saltwater lake in India and was selected as a “Ramsar Site.” A catchment area of the lake is delineated, and micro-watersheds are selected for detailed analysis. A primary survey is done to know the impacts and causes of changes in the lake. The study indicates significant green cover changes in three seasons over the years. Because of the loss in green cover, the soil is losing its moisture, affecting the cropping pattern and agriculture production in the area. Factors causing the drying of the lake are affecting its ecosystem and the number of birds coming to it.
TopIntroduction
The Aravalli range is one of the oldest hill systems in the world. They came into existence by an upheaval of organic nature at the close of the Dharwar era and dominated the geography of India in the Palaeozoic and Mesozoic periods. These are stretched in about 692 Km across Gujarat, Rajasthan, Haryana, and Delhi (Dhabriya, 1988). The Aravalli range plays a significant role in the area as they combat desertification, recharge groundwater, balance the ecology, check the drought occurrence, and provide minerals and other resources (Kohli & Arora, 2018). Many rives like Banas, Luni, Sakhi Sabarmati, Sahibi, Sota and others originated from it. Moreover, many streams originated from these hill system feeds various lakes like Pichola, Rajsamand, Kanota, Jaisamand, Anasagar, Siliserh, Man Sagar and many more (see Figure 1), one of them is a Salt Lake, i.e., the sambhar lake which is an important natural assets with considerable aesthetic, recreational, scientific, cultural, economic, and ecological value (Singh, 2013). In the arid zone of the Thar desert, salt lakes are originated due to the formation of depression by neo-tectonic disturbances along lineaments (Kale, 2014).
Figure 1. Important lakes around Aravalli range
For the last 30 years, these hill systems are facing changes because of mining, deforestation, population growth, and other activities. Because of all the above factors, the land use land cover (LULC) of the area surrounding the Aravalli range is changing rapidly. The land cover defines as the physical state of the land surface, including water bodies, forests, wetland, cropland, etc., whereas land use refers to biophysical resources used by humans. Therefore, land use land cover analysis is essential for environmental studies and natural resource management. This information also helps to understand the relationship between forest, wetland, cropland, settlement, etc. (Singh, Singh, Singh, & Mukherjee, 2016). Furthermore, the ecosystem functions of Aravalli’s are changing due to changes in land use land cover, which is resulting in the drying of many rives and other water bodies. To understand this, the catchment of Sambhar Lake is taken as an example (see Figure 2 and Figure 3).
Figure 2. Google Earth image of December month- year 2001
Figure 3. Google Earth image of December month- year 2018- increased salt mining area
For achieving this study first catchment area is delineated, and watersheds are taken from the Soil and Land Use Survey of India (SLUSI), and then change in vegetation cover and land use land cover is assessed using Normalised Difference Vegetation Index (NDVI) and Geographic Information System (GIS). GIS technology and remote sensing have emerged as a decent tool for analysing the change in land use land cover of the area at spatial and temporal scales. (Singh, Singh, Singh, & Mukherjee, 2016) NDVI is used to calculate the value of vegetation index using multispectral remote sensing data (Zaitunah, Samsuri, Ahmad, & Safitri, 2018). Analysis of land use land cover is focused on the study, on three aspects- detection of changes in land use land cover using Landsat image between 1998-2008-2018 and Bhuvan geoportal image between 2006-2012-2018, identification of nature of changes, and assessment of the pattern of the changes. At the end of the study, some strategies are suggested for the sustainable management of the study area.