Sajid Mahmood

IMPACT OF URBANIZATION ON INFLOWS AND SEDIMENTATION LOAD IN RAWAL LAKE OF PAKISTAN

An agro-based country, Pakistan is largely dependent on one of the world’s largest contagious Indus Basin Irrigation System (IBIS) for the agriculture (Azmat, 2015). Therefore, in order to meet with the needs of food, fiber and for other purposes due to increase of population and immense pressure on the water resources system every country is trying to do its best for water resources storage, regulation and management. The variations in climate and catchment characteristics largely effecting the inflows of the rivers (Azmat et al., 2016; Shakoor et al., 2015). However, water resources are largely affected by several natural hazards due change in climate conditions such as sedimentation, earthquakes and floods etc. It has been documented that world’s 13 large rivers carrying 5.8 billion tons of sediments to the reservoirs every year (Nasir et al., 2006). Poor management of erosion prone areas has resulted in flooding and rapid filling of water reservoirs (Nasir et al., 2006). Kahlown et al. (2002) stated that the Indus and its tributaries carries about 0.35 MAF of sediment load annually, almost 60% (0.2 MAF) of which deposits in the reservoirs, canals and irrigation fields. Islamabad and Rawalpindi are two very important and twin cities of Pakistan. Rawalpindi city is one of the largest populated cities of province Punjab having population of about more than 1.41 million, according to 1998 census. Catchment area of the Rawal Lake is reducing very rapidly due to urbanization during last few decades which leads to poor quality and quantity of inflows to the lake. Indeed, an increase in sediment load caused by the urbanization into the reservoir due to the exposure of bare lands which further approaches to the destruction of natural land cover. Rawal Dam is a major source of drinking water to Rawalpindi, however, the dam capacity and water quality is diminishing with time therefore, water is getting polluted and also caused sedimentation. The rate of urban growth can seriously challenge the integrity of rivers and streams. Number of studies (Moehansyah et al., 2002; Thothong et al., 2011; Huang et al., 2015; Bashir et al., 2013) have carried out to analyze the impact of land use change on inflows and sedimentation of the basin prevailing to the urbanization. These studies suggest that hydrological changes in urban watersheds can most often be attributed to the modification of stream characteristics which govern discharge, stream chemistry, stream/ floodplain interactions and channel morphology. As a result, urbanization is thought to cause reduced base inflows, increased frequency and magnitude of peak discharges, increased sediment loads, reduction in channel and floodplain complexity and impaired water quality (Dunne and Leopold, 1978). Therefore, the aim of this study was to analyze the inflow variations due to urbanization and its implications on sedimentation of the Rawal Dam.

Groundwater Contamination from Agro-chemicals in Irrigated Environment : Field Trials

This paper highlights on the increasing fears that chemicals in agriculture have found their way into drinking water causing health complications. In fact, many chemicals have not had these effects but waiting to do so by moving into groundwater, sinking slowly and finally going into taps. Nitrate fertilizer is largely blamed for these fears. Use of fertilizer obviously would increase manifold to meet the food needs arising out of population explosion and it would further aggravate the situation. Therefore, the use of chemicals in agriculture presents a global alarm particularly for Pakistan where environmental degradation is rampant and unfortunately least attended. It necessitates development of Best Management Practices (BMP’s) to reduce groundwater contamination resulting from application of agricultural chemicals especially the fertilizer. The study conducted at the University of Agriculture for reducing fertilizer pollution of groundwater is presented in this article.