Description

Introduction

1.1 General

Land-use change is a very important issue considering global dynamics and their response to hydrologic characteristics of soil and water management in a catchment. The assessment of Land-use and Land cover (LULC) changes on hydrology is essential for the development of sustainable water resource strategies. Understanding the impacts of small change in each LULC class on hydrological components will greatly improve the predictability of hydrological consequences to LULC changes and thus can help stakeholders make better decisions. Land use activities, development and management of water resource are interdependent and thus land use/land cover (LULC) change has significant impacts on water quality and quantity such as surface runoff, groundwater, over a range of temporal and spatial scales. Alteration in land use and climate invokes the Hydrological response dynamics (an integrated indicator of watershed conditions) and water response in various river basins. Expanded impervious surfaces, such as parking lots, roofs, sidewalks, and driveways, block the precipitation infiltrating into the groundwater and increase the total volume and peak discharge of the streamflow. Increase in settlements, deforestation, expansion of agricultural area and intensive grazing yields high runoff and sediment yield. These changes enlarge the quantity, velocity and intensity of runoff.

Understanding how changes in distinctive land use/land cover (LULC) types influence the basin hydrology would greatly improve the predictability of the hydrological consequences of LULC dynamics for sustainable water resource management. For foresightful and sustainable water management, reliable information on the water balance components today and their future changes could be a prerequisite. Both natural erosional dynamics and human induced changes have intense effects on the land use/land cover (LULC) of the global earth. These LULC changes have a considerable impact on soil and water. Hydrologic response at the watershed level is greatly impacted by land use land cover change (LULC). Land use land cover (LULC) changes may end up in shortage of water, flood risk and erosion and thus contribute to the deterioration of living conditions. Quantitative assessment of LULC impacts on runoff generations is important for water resources development. General statements about land-water interactions need to be continuously questioned to determine whether they represent the best available information and the available information supports decision making processes for developmental activities in a sustainable way. Regional-scale hydrological models can play a vital role in river basin management. They simulate impacts on possible future changes of LULC and help to find measures improving the adaptive capacity of river basins. Expansion of agriculture, urbanization, deforestation and the day to day activities of mankind resulted in a temporal and spatial change in land use land cover have affected water flow pathways and water balance. The impacts of LULC change are likely to be severe in developing countries due to lack of adaptability. Developing countries where agriculture serves as the backbone of the economy and ensure the wellbeing of people, the adverse effects of land use land cover change are diverse. Many river basins in India, where drastic LULC change has taken place in the last century, have been facing adverse reoccurring hydro meteorological extremes such as floods and droughts in the recent times. The future climate and LULC changes within the basin are the vital reasons for such changes within the hydrological regime. In addition to this, the developmental activities pursued throughout the country are expected to put additional stress on future water availability. Hence there is a need to understand and point out the impact of such changes on water resources availability, so as to develop suitable adaptation strategies. Stream flows are sensitive to land use change i.e. minor change in land use causes major changes to stream flows.