Dams for water supply usually represent an untapped hydroelectric potential. It is a small energetic potential, in most situations, usually requiring a particular solution to be viable. The use of pumps as power turbi...Dams for water supply usually represent an untapped hydroelectric potential. It is a small energetic potential, in most situations, usually requiring a particular solution to be viable. The use of pumps as power turbines often represents an alternative that enables the power generation in hydraulic structures already in operation, as is the case of dams in water supply systems. This potential can be exploited in conjunction with the implementation of PV modules on the water surface, installed on floating structures, both operating in a hydro PV hybrid system. The floating structure can also contribute to reducing the evaporation of water and providing a small increase in hydroelectric power available. This paper presents a pre-feasibility study for implementation of a hydroelectric power plant and PV modules on floating structures in the reservoir formed by the dam of Val de Serra, in southern Brazil. The dam is operated to provide drinking water to about 60% of the population of the city of Santa Maria, in the state of Rio Grande do Sul, in southern Brazil. The pre-feasibility study conducted with Homer software, version Legacy, indicated that the hydroelectric plant with a capacity of 227 kW can operate together with 60 kW of PV modules. This combination will result (in one of the configurations considered) in an initial cost of USD$ 1715.83 per kW installed and a cost of energy of USD$ 0.059/kWh.展开更多
in arid and semi-arid areas, artificial recharge is a key technology in groundwater resources management, and a reliable estimate of artificial recharge is necessary to its sustainable development. Several methods are...in arid and semi-arid areas, artificial recharge is a key technology in groundwater resources management, and a reliable estimate of artificial recharge is necessary to its sustainable development. Several methods are available to estimate the artificial recharge; however, most of them require field data or model parameters, thus limiting their applications. To overcome this limitation, we presented an analytical method to estimate the artificial recharge through monitoring the water release by piezometer and analysing the controlling factors of the artificial recharge from a hill dam in Tunisia. A total of 97 measurements of water flow in the streambed recorded from 4 gauging stations were analysed. Results indicated that the average infiltration velocity ranged from 0.043 to 0.127 m/d and the infiltration index varied from 7.6 to 11.8 L/（s.km）. Pearson＇s correlation coefficient analysis shows that the infiltration index, the stream gradient, the thickness of unsaturated zone, the number of infiltration pond, the stream geometry, and the water flow rate were found to be the main factors in determining the infiltration. The high correlation coefficients （0.908 for the number of infiltration pond and 0.999 for the stream geometry） mean that the number of infiltration pond and the stream geometry are the most influential factors. Time variations of groundwater level were used to analyze the recharge effects on the piezometry of aquifer. The analysis showed that during the artificial recharge, the water table increased at a rate of 5 mm/d and that the increase was limited to the area surrounding the recharge site. Based on the results of the study, building infiltration ponds along streambed and improving the potential of rainwater harvesting over the study area are recommended.展开更多
1-D and 2-D mathematical models for dam break flow were established and verified with the measured data in laboratory. The 1-D and 2-D models were then coupled, and used to simulate the dam break flow from the reservo...1-D and 2-D mathematical models for dam break flow were established and verified with the measured data in laboratory. The 1-D and 2-D models were then coupled, and used to simulate the dam break flow from the reservoir tail to the dam site, the propagation of dam break waves in the downstream channel, and the submergence of dam break flow in the downstream town with the hydrodynamics method. As a numerical example, the presented model was employed to simulate dam break flow of a hydropower station under construction. In simulation, different dam-break durations, upstream flows and water levels in front of dam were considered, and these influencing factors of dam break flow were analyzed, which could be referenced in planning and designing hydropower stations.展开更多
基金The authors wish to thank the institutions involved for their support to research activities related to renewable energy,which resulted,among other things,in this articleSpecifically,the third author would like to thank the partial financial support provided by CNPq through a support grant for research productivity.
文摘Dams for water supply usually represent an untapped hydroelectric potential. It is a small energetic potential, in most situations, usually requiring a particular solution to be viable. The use of pumps as power turbines often represents an alternative that enables the power generation in hydraulic structures already in operation, as is the case of dams in water supply systems. This potential can be exploited in conjunction with the implementation of PV modules on the water surface, installed on floating structures, both operating in a hydro PV hybrid system. The floating structure can also contribute to reducing the evaporation of water and providing a small increase in hydroelectric power available. This paper presents a pre-feasibility study for implementation of a hydroelectric power plant and PV modules on floating structures in the reservoir formed by the dam of Val de Serra, in southern Brazil. The dam is operated to provide drinking water to about 60% of the population of the city of Santa Maria, in the state of Rio Grande do Sul, in southern Brazil. The pre-feasibility study conducted with Homer software, version Legacy, indicated that the hydroelectric plant with a capacity of 227 kW can operate together with 60 kW of PV modules. This combination will result (in one of the configurations considered) in an initial cost of USD$ 1715.83 per kW installed and a cost of energy of USD$ 0.059/kWh.
文摘in arid and semi-arid areas, artificial recharge is a key technology in groundwater resources management, and a reliable estimate of artificial recharge is necessary to its sustainable development. Several methods are available to estimate the artificial recharge; however, most of them require field data or model parameters, thus limiting their applications. To overcome this limitation, we presented an analytical method to estimate the artificial recharge through monitoring the water release by piezometer and analysing the controlling factors of the artificial recharge from a hill dam in Tunisia. A total of 97 measurements of water flow in the streambed recorded from 4 gauging stations were analysed. Results indicated that the average infiltration velocity ranged from 0.043 to 0.127 m/d and the infiltration index varied from 7.6 to 11.8 L/（s.km）. Pearson＇s correlation coefficient analysis shows that the infiltration index, the stream gradient, the thickness of unsaturated zone, the number of infiltration pond, the stream geometry, and the water flow rate were found to be the main factors in determining the infiltration. The high correlation coefficients （0.908 for the number of infiltration pond and 0.999 for the stream geometry） mean that the number of infiltration pond and the stream geometry are the most influential factors. Time variations of groundwater level were used to analyze the recharge effects on the piezometry of aquifer. The analysis showed that during the artificial recharge, the water table increased at a rate of 5 mm/d and that the increase was limited to the area surrounding the recharge site. Based on the results of the study, building infiltration ponds along streambed and improving the potential of rainwater harvesting over the study area are recommended.
基金the National Basic Research Program of China(973 Program, Grant No. 2003CB415203)the National Natural Science Foundation of China (Grant No.50579054).
文摘1-D and 2-D mathematical models for dam break flow were established and verified with the measured data in laboratory. The 1-D and 2-D models were then coupled, and used to simulate the dam break flow from the reservoir tail to the dam site, the propagation of dam break waves in the downstream channel, and the submergence of dam break flow in the downstream town with the hydrodynamics method. As a numerical example, the presented model was employed to simulate dam break flow of a hydropower station under construction. In simulation, different dam-break durations, upstream flows and water levels in front of dam were considered, and these influencing factors of dam break flow were analyzed, which could be referenced in planning and designing hydropower stations.
