Appropriate quantification and identification of the groundwater distribution in a hydrological basin may provide necessary information for effective management,planning and development of groundwater resources.Ground...Appropriate quantification and identification of the groundwater distribution in a hydrological basin may provide necessary information for effective management,planning and development of groundwater resources.Groundwater potential assessment and delineation in a highly heterogeneous environment with limited Spatiotemporal data derived from Gelana watershed of Abaya Chamo lake basin is performed,using integrated multi-criteria decision analysis(MCDA),water and energy transfer between soil and plant and atmosphere under quasi-steady state(WetSpass)models.The outputs of the WetSpass model reveal a favorable structure of water balance in the basin studied,mainly using surface runoff.The simulated total flow and groundwater recharge are validated using river measurements and estimated baseflow at two gauging stations located in the study area,which yields a good agreement.The WetSpass model effectively integrates a water balance assessment in a geographical information system(GIS)environment.The WetSpass model is shown to be computationally reputable for such a remote complex setting as the African rift,with a correlation coefficient of 0.99 and 0.99 for total flow and baseflow at a significant level of p-value<0.05,respectively.The simulated annual water budget reveals that 77.22%of annual precipitation loses through evapotranspiration,of which 16.54%is lost via surface runoff while 6.24%is recharged to the groundwater.The calibrated groundwater recharge from the WetSpass model is then considered when determining the controlling factors of groundwater occurrence and formation,together with other multi-thematic layers such as lithology,geomorphology,lineament density and drainage density.The selected five thematic layers through MCDA are incorporated by employing the analytical hierarchy process(AHP)method to identify the relative dominance in groundwater potential zoning.The weighted factors in the AHP are procedurally aggregated,based on weighted linear combinations to provide the groundwater potential index.Based on the potential indexes,the area then is demarcated into low,moderate,and high groundwater potential zones(GWPZ).The identified GWPZs are finally examined using the existing groundwater inventory data(static water level and springs)in the region.About 70.7%of groundwater inventory points are coinciding with the delineated GWPZs.The weighting comparison shows that lithology,geomorphology,and groundwater recharge appear to be the dominant factors influence on the resources potential.The assessment of groundwater potential index values identify 45.88%as high,39.38%moderate,and 14.73%as low groundwater potential zones.WetSpass model analysis is more preferable in the area like Gelana watershed when the topography is rugged,inaccessible and having limited gauging stations.展开更多
The impact of land-use on surface runoff and soil erosion is still poorly understood at basin scale. Thus in the Western Jilin Ecosystem (WJE), surface runoff and soil erosion were measured against identified land-use...The impact of land-use on surface runoff and soil erosion is still poorly understood at basin scale. Thus in the Western Jilin Ecosystem (WJE), surface runoff and soil erosion were measured against identified land-use types in the basin. Due to the spatial nature of the analysis, GIS ArcMap version 9.1 and the WetSpass model were used in the simulation process. In the study, the WetSpass model was extended with the Dynamic Sediment Balance Equation (Ziegler et al., 1997), to simulate and quantify soil erosion. A hypothetical natural grassland scenario was developed for the study area and compared with the present land-use management conditions. The results indicate significant differences in runoff and soil erosion across the different land-use types both within and between the two scenarios. Calculated averages of surface runoff and soil erosion for the present land-use management were 48.03 mm/a and 83.43 kg/(m 2·a) respectively. Those for the hypothetical natural grassland scenario were 24.70 mm/a and 78.36 kg/(m 2·a) . Thus an overall decrease in runoff and soil erosion was observed as the conditions changed from the present land-use management to the hypothetical natural grassland state. Under the present land-use management, urban settlements exhibited the highest surface runoff but one of the least soil erosions, while bare-lands showed the highest soil erosion. It was more generally observed that runoff and erosion varies with vegetation type/density. It was concluded based on the research findings that the present land-use management might not be the best scenario for the ecosystem as it showed increased basin runoff and soil erosion in comparison with the natural grassland vegetation. Since no best scenario was simulated for or advanced in the study, further research to develop a more balanced land management system is thus required. The findings of the study can assist in the identification of vulnerable/fragile ecosystems in the basin and to guide sustainable future planning and development of the basin.展开更多
结合WetSpass模型与地理信息系统(geographic information system,GIS)、遥感(remote sense,RS)技术分析了城市扩张引起的土地利用类型变化对北京平原区降水入渗补给量的影响.在估算出1982年和2007年降水入渗补给量的基础上,将2007年土...结合WetSpass模型与地理信息系统(geographic information system,GIS)、遥感(remote sense,RS)技术分析了城市扩张引起的土地利用类型变化对北京平原区降水入渗补给量的影响.在估算出1982年和2007年降水入渗补给量的基础上,将2007年土地利用类型还原成1982年的情景重新估算,利用转移矩阵分析两年土地利用类型的相互转化关系,同时,基于GIS空间数据统计功能,计算出不同土地利用类型下的地下水补给量.结果表明,1982年至2007年,研究区内水浇地减少874km2,其中517km2转变为城镇建设用地.相对于1982年,2007年城镇建设用地扩张了831km2,区内降水入渗补给量减少约3 000万m3.研究成果可以为北京平原区的地下水资源保护及土地资源配置提供较为科学的参考.展开更多
文摘Appropriate quantification and identification of the groundwater distribution in a hydrological basin may provide necessary information for effective management,planning and development of groundwater resources.Groundwater potential assessment and delineation in a highly heterogeneous environment with limited Spatiotemporal data derived from Gelana watershed of Abaya Chamo lake basin is performed,using integrated multi-criteria decision analysis(MCDA),water and energy transfer between soil and plant and atmosphere under quasi-steady state(WetSpass)models.The outputs of the WetSpass model reveal a favorable structure of water balance in the basin studied,mainly using surface runoff.The simulated total flow and groundwater recharge are validated using river measurements and estimated baseflow at two gauging stations located in the study area,which yields a good agreement.The WetSpass model effectively integrates a water balance assessment in a geographical information system(GIS)environment.The WetSpass model is shown to be computationally reputable for such a remote complex setting as the African rift,with a correlation coefficient of 0.99 and 0.99 for total flow and baseflow at a significant level of p-value<0.05,respectively.The simulated annual water budget reveals that 77.22%of annual precipitation loses through evapotranspiration,of which 16.54%is lost via surface runoff while 6.24%is recharged to the groundwater.The calibrated groundwater recharge from the WetSpass model is then considered when determining the controlling factors of groundwater occurrence and formation,together with other multi-thematic layers such as lithology,geomorphology,lineament density and drainage density.The selected five thematic layers through MCDA are incorporated by employing the analytical hierarchy process(AHP)method to identify the relative dominance in groundwater potential zoning.The weighted factors in the AHP are procedurally aggregated,based on weighted linear combinations to provide the groundwater potential index.Based on the potential indexes,the area then is demarcated into low,moderate,and high groundwater potential zones(GWPZ).The identified GWPZs are finally examined using the existing groundwater inventory data(static water level and springs)in the region.About 70.7%of groundwater inventory points are coinciding with the delineated GWPZs.The weighting comparison shows that lithology,geomorphology,and groundwater recharge appear to be the dominant factors influence on the resources potential.The assessment of groundwater potential index values identify 45.88%as high,39.38%moderate,and 14.73%as low groundwater potential zones.WetSpass model analysis is more preferable in the area like Gelana watershed when the topography is rugged,inaccessible and having limited gauging stations.
文摘The impact of land-use on surface runoff and soil erosion is still poorly understood at basin scale. Thus in the Western Jilin Ecosystem (WJE), surface runoff and soil erosion were measured against identified land-use types in the basin. Due to the spatial nature of the analysis, GIS ArcMap version 9.1 and the WetSpass model were used in the simulation process. In the study, the WetSpass model was extended with the Dynamic Sediment Balance Equation (Ziegler et al., 1997), to simulate and quantify soil erosion. A hypothetical natural grassland scenario was developed for the study area and compared with the present land-use management conditions. The results indicate significant differences in runoff and soil erosion across the different land-use types both within and between the two scenarios. Calculated averages of surface runoff and soil erosion for the present land-use management were 48.03 mm/a and 83.43 kg/(m 2·a) respectively. Those for the hypothetical natural grassland scenario were 24.70 mm/a and 78.36 kg/(m 2·a) . Thus an overall decrease in runoff and soil erosion was observed as the conditions changed from the present land-use management to the hypothetical natural grassland state. Under the present land-use management, urban settlements exhibited the highest surface runoff but one of the least soil erosions, while bare-lands showed the highest soil erosion. It was more generally observed that runoff and erosion varies with vegetation type/density. It was concluded based on the research findings that the present land-use management might not be the best scenario for the ecosystem as it showed increased basin runoff and soil erosion in comparison with the natural grassland vegetation. Since no best scenario was simulated for or advanced in the study, further research to develop a more balanced land management system is thus required. The findings of the study can assist in the identification of vulnerable/fragile ecosystems in the basin and to guide sustainable future planning and development of the basin.
文摘结合WetSpass模型与地理信息系统(geographic information system,GIS)、遥感(remote sense,RS)技术分析了城市扩张引起的土地利用类型变化对北京平原区降水入渗补给量的影响.在估算出1982年和2007年降水入渗补给量的基础上,将2007年土地利用类型还原成1982年的情景重新估算,利用转移矩阵分析两年土地利用类型的相互转化关系,同时,基于GIS空间数据统计功能,计算出不同土地利用类型下的地下水补给量.结果表明,1982年至2007年,研究区内水浇地减少874km2,其中517km2转变为城镇建设用地.相对于1982年,2007年城镇建设用地扩张了831km2,区内降水入渗补给量减少约3 000万m3.研究成果可以为北京平原区的地下水资源保护及土地资源配置提供较为科学的参考.
