INTRODUCTION

Landscape refers to a portion of heterogeneous terrain with the interacting ecosystems and is characterized by its dynamics, which are governed by human activities and natural processes (Ramachandra et al., 2012a). Human induced land use and land cover (LULC) changes have been the major driver of the landscape dynamics at local levels.  Understanding of landscape dynamics helps in the sustainable management of natural resources (such as water, land, etc.). Forests are degrading due to large scale anthropogenic activities involving the conversion into to agriculture fields (Lin and Wei 2008), or horticulture lands, hydro schemes etc. in turn affecting the hydrological regime (Ramachandra et al 2013, Bonella et al 2010, Lin and Wei 2008). This also has led to higher soil loss through erosion affecting the productivity and water holding capacity of the soils (Subramanian 1998), increased agricultural activities and human interference leads to higher water requirement, if not catered through other available sources leads to agriculture drought conditions. Altered and lower flows in the river are key contributors to the decline in river health and its environs manifested in ways such as increasing algal blooms, a decline in native fish numbers and increases in exotic species, and a decline of wetlands (Sahbaz Khan, 2004).  To overcome such issues, it is necessary to analyse and manage the capacity of the basins to supply resources without losing its current potential through water balance studies (Subramanya 2005, Raghunath 1985) in conjunction with GIS and remote sensing (Neil and Matthew 2012, Mallikarjuna et al 2013). Remote Sensing (Ramchandra et al 2012a, Vinay et al 2012) has advantages such as wider synoptic coverage of the earth surface with varied temporal, spatial and spectral resolutions to monitor these changes.

Drought is a natural phenomenon that has significant adverse effect on the socio-economic, agricultural, and environmental conditions (Nezar and Ali, 2007; Bhuiyan et al, 2006) caused due to the water deficiency either meteorologically or due to anthropogenic activities such as excessive human activities (agriculture, horticulture etc.) due to, increasing population and increased demand of natural resources that are exploited at a very large scale (Ramachandra and Bharath, 2012, Ramachandra et al 2012a). A drainage basin perspective is essential for understanding the upstream downstream connectivity of water supplies, water demands, and emerging water problems. The land use information derived from temporal remote sensing data integrated with the long term meteorological information such as rainfall (Reshma et al 2012), temperature, etc. aid in assessing the water balance of a river basin through quantification of hydrological parameters such as runoff, infiltration, base flow etc. The objective of the study is to model hydrological dynamics of a river basin to monitor the water availability including drought conditions. The current work is done at sub basin level in the Sharavathi river basin, central Western Ghats.