Reservoirs are usually exposed to sediment accumulation problems that will lead to reduction in their storage capacity. This problem directly affects the performance of the dams and causes shortage of their useful lif...Reservoirs are usually exposed to sediment accumulation problems that will lead to reduction in their storage capacity. This problem directly affects the performance of the dams and causes shortage of their useful life. The simplest technique to estimate sediment deposition rate is using sediment rating curve with sediment trapping efficiency (TE) of the reservoir. Many empirical and semi-empirical approaches have been suggested for to determine this term depending on the annual inflow rate, reservoir characteristics and features of the catchments area. In this study six different empirical methods depending on the residence time principle (water retention time) were used. These approaches were reviewed and applied to determine TE of Mosul dam reservoir (MDR) for period 1986 to 2011. The monthly operating data for inflow, outflow and water elevations for MDR were used to determine monthly TE and long-term TE for whole period of MDR using the mentioned methods. Furthermore, the monthly inflow rate for River Tigris upstream MDR, its sediment rating curve and sediment feeding from valleys around MDR were used to estimate the amount sediment coming to the reservoir. The results provided by these methods for TE with sediment coming to MDR were used to compute the amount of sediment deposited in MDR on monthly bases during this period. The results obtained were evaluated using observed bathymetric survey data that had been collected in 2011 after 25 years of the operation of the dam. The results showed all the mentioned methods gave convergent results and they were very close to bathymetric survey results for estimating the volume of sediment deposited especially that proposed by Ward which gave 0.368% percentage error. Furthermore, the result computed using monthly TE gave good agreement if compared with that long-term TE where the percentage error was ranging between –3.229% to 1.674% for monthly adopted data and –4.862% to?–2.477% for whole period data. It is believed that this work will help others to use thi展开更多
Present work introduces the sustainable useful storage capacity as the minimum storage capacity able to satisfy the water demand for drinkable, industrial and irrigational purposes and necessary in order to overcome w...Present work introduces the sustainable useful storage capacity as the minimum storage capacity able to satisfy the water demand for drinkable, industrial and irrigational purposes and necessary in order to overcome water deficit situations which, at least in Central Southern Italy, occur in the summer, when agricultural demand is really high. Sediment volumes to be removed from the reservoir bottom will be calculated as the difference between the current and the sustainable useful storage capacities of the reservoir in study. The calculation methodology of the useful sustainable storage capacity, based on the reservoir water balance between inflows at the reservoir and water demand, has been applied to the Camastra reservoir (Basilicata, Southern Italy), for which numerous reliable data including more than 40 years of inflows and water supplied volumes and data relative to 7 bathymetric surveys are available. Result analysis shows that this methodology, at least in the study case, enables sediment quantities to be removed more sustainably from a technical, economical and environmental point of view.展开更多
文摘Reservoirs are usually exposed to sediment accumulation problems that will lead to reduction in their storage capacity. This problem directly affects the performance of the dams and causes shortage of their useful life. The simplest technique to estimate sediment deposition rate is using sediment rating curve with sediment trapping efficiency (TE) of the reservoir. Many empirical and semi-empirical approaches have been suggested for to determine this term depending on the annual inflow rate, reservoir characteristics and features of the catchments area. In this study six different empirical methods depending on the residence time principle (water retention time) were used. These approaches were reviewed and applied to determine TE of Mosul dam reservoir (MDR) for period 1986 to 2011. The monthly operating data for inflow, outflow and water elevations for MDR were used to determine monthly TE and long-term TE for whole period of MDR using the mentioned methods. Furthermore, the monthly inflow rate for River Tigris upstream MDR, its sediment rating curve and sediment feeding from valleys around MDR were used to estimate the amount sediment coming to the reservoir. The results provided by these methods for TE with sediment coming to MDR were used to compute the amount of sediment deposited in MDR on monthly bases during this period. The results obtained were evaluated using observed bathymetric survey data that had been collected in 2011 after 25 years of the operation of the dam. The results showed all the mentioned methods gave convergent results and they were very close to bathymetric survey results for estimating the volume of sediment deposited especially that proposed by Ward which gave 0.368% percentage error. Furthermore, the result computed using monthly TE gave good agreement if compared with that long-term TE where the percentage error was ranging between –3.229% to 1.674% for monthly adopted data and –4.862% to?–2.477% for whole period data. It is believed that this work will help others to use thi
文摘Present work introduces the sustainable useful storage capacity as the minimum storage capacity able to satisfy the water demand for drinkable, industrial and irrigational purposes and necessary in order to overcome water deficit situations which, at least in Central Southern Italy, occur in the summer, when agricultural demand is really high. Sediment volumes to be removed from the reservoir bottom will be calculated as the difference between the current and the sustainable useful storage capacities of the reservoir in study. The calculation methodology of the useful sustainable storage capacity, based on the reservoir water balance between inflows at the reservoir and water demand, has been applied to the Camastra reservoir (Basilicata, Southern Italy), for which numerous reliable data including more than 40 years of inflows and water supplied volumes and data relative to 7 bathymetric surveys are available. Result analysis shows that this methodology, at least in the study case, enables sediment quantities to be removed more sustainably from a technical, economical and environmental point of view.
