Evaluation of Land-Use/Land Cover Changes in Indus Delta through Geo-Spatial Techniques

Abstract

The Indus River travels on extensive Indus plain and divided in to several major and minor creeks. It is called as ‘Indus Delta’. During several decades, it has been observed that the flow of Indus water has decreased in lower Indus plain particularly Indus delta, due to this sea water entering creeks of Indus delta resulting land-use / land cover have drastic changes and consequently causing the socio-economic crises in the study area. Land use / Land cover changes are valuable parts of the worldwide environmental changes (Dickinson, 1995; Hall et al. 1995; Dewidar, 2004). Due to urban and agricultural developments drastic change in LULC has been observed in the world. Satellite Remote Sensing is one of the most readily available and up-to-date sources for detection, quantification and mapping of LULC patterns and changes. The objective of the study is (i) to identify existing Land use/ Land cover in the study region. (ii) To explore temporal Land-use / land cover (LULC) changes in past 20 years through satellite imageries using Geo-Spatial Technologies (iii) To execute standard Remote Sensing procedures to extract Land-use / Land cover (LULC) classes (iv) To evaluate Land-use / Land cover impacts on Land Surface Temperature (LST) in the Indus Delta (v) To analyze the variable character of Normalize Difference Vegetation Index (NDVI) in the study area.(vi) To discover relationship in spectral and informal classes.(vii) To analyze the relationship between LST and NDVI with LULC classes. (viii) To monitor the impacts on Socio-economic activity in study region. (ix) To develop the questionnaire and fill with local person field survey. (x) To evaluate change of environmental resources, currently practiced in the field of ecology. The current research study divided into two broad categories with respect to seasons: Pre-monsoon period and Post-monsoon period. Satellite images of Landsat-5 TM, Landsat-7 ETM+ and Landsat-8 OLI / TIRS were used in each period of the study, acquired on 27th April-1992, 8th March-2000, 29th April-2010, and 8th April-2014 in premonsoon period and 28th October-1989, 24th September-2000, 7th November-2010 and 20th December-2014 in post monsoon period. Four techniques: Supervised Classification, Change Detection, Normalize Difference Vegetation Index (NDVI) and ix Land Surface Temperature (LST) analysis was performed in the study area. Ten Landuse / land cover were selected namely, dense mangrove, normal mangrove, cultivated land, other vegetation, wet mudflat, dry mudflat, wet barren / vacant land, dry barren / vacant land, turbid water and deep water. The result indicate of the research is that LULC classes were increased except dry barren / vacant land in post monsoon period. Mangrove forest increased gradually with aforesaid period and year. The reason of that different government and private organization like Sindh Forest Department, IUCN, WWF etc. were plantation of mangrove forest in several areas of Keti Bunder, Shah Bunder, Bin Qasim area and other areas of creek in Indus Delta, due to this normal mangrove was increased as compare to dense mangrove. It has been revealed from this study that NDVI and LST values derive from Landsat images of pre-monsoon period and post monsoon period of aforesaid years. It was observed that NDVI value of dense mangrove, normal mangrove, cultivated land and other vegetation were high in pre-monsoon period as compared to post monsoon period, due to floods and rainfall during monsoon period. While in term of area, greenness area was high in post monsoon period. While the LST was high in post monsoon period and temperature was raised continuously due to global warming. As far as LULC are concerned the LST of turbid water and deep water was low and dry barren / vacant land and wet barren / vacant land was high. A linear regression analysis between LST & NDVI for LULC classes excluding turbid water and deep water in the study area. The results show that significant moderate and negative correlation with LST and NDVI. When LST values of LULC like dry barren / vacant land, wet barren / vacant land are increased, then the NDVI value of LULC are decreased. The relationship between LST and NDVI of Post Monsoon period of 20th December-2014 was strong and negative. It has been found through questionnaire and field surveys, it was observed that drastic changes in socio-economic activities of the area, LULC patterns and climatic change with respect time to time. Mostly respondents said agricultural land, mangroves and biodiversity of this region is under serious condition. Last few decades, Red rice cultivated in this region but now is almost non-existent, similarly mangrove species were abundant last few decades, but now only four species survived, due to lack of fresh water x and sea water intrusion. More than 117,823 acres of agricultural land has been affected from sea water intrusion. Huts around creeks were made of wood, chatai and dry straw, because cyclone comes every year, while settlements of agricultural land were made cemented home. Relationship between LULC and climate change was significant correlation, because floods and rainfall occur during monsoon period, due to this houses, livestock and agricultural land damage around the katcha area of Indus River. While during post-monsoon period, those areas were fertile and suitable to agriculture.