On the water and sediment yield of Chitral river, Pakistan
2003
Rehman, S.S. (Peshawar Univ. (Pakistan). Dept. of Environmental Sciences) | Sabir, M.A.
Discharge and sediment load of the Chitral River has been analyzed and discussed to understand hydro-meteorological characteristics of the Chitral river and its tributary system. The paper not only reviews some of the published data by WAPDA but some new data has also been incorporated in the study. The result shows that mean annual runoff of the Chitral River usually remains close to 7 MAF from a catchment area of about 11400km2. Extraordinary flows exceeding 9 MAF have also been recorded. Peak average discharge of about 856m3s-1 is experienced in July whereas a minimum flow of 68.6m3s-1 is usually recorded in March. The effect of snowmelt on the runoff can be gauged from the fact that 74% of the total annual runoff takes between June & September, when there is little rainfall in the area but excessive snow melts due to high summer temperatures. The volume of sediment transported by this river is also significantly large and on average about 22 and 1.6 million tones of suspended and dissolved load is annually transported by the Chitral River respectively. Similarly the bed- load is estimated at approximately 5.5mt. This high sediment load evidently signifies the higher erosion rates (2632 tones/km2) operating in the Chitral river catchment. Besides, physical parameters such as pH, temperature, conductivity, turbidity, dissolved oxygen and chemical parameters like Ca, Na, K, HCO3, Cl, SO4 & NO3 have also been determined for Chitral river and its tributaries. Most of these parameters fall within the safe limits for agricultural and domestic uses except the suspended solids, which are beyond the safety limits for the purpose of drinking.
显示更多 [+] 显示较少 [-]