For the analysis of river evolution, the use of quantitative parameters can be quite useful in order to assess changes in the channel planform. Among the several parameters proposed by different authors in a number of...For the analysis of river evolution, the use of quantitative parameters can be quite useful in order to assess changes in the channel planform. Among the several parameters proposed by different authors in a number of papers, channel length and width, braiding and sinuosity indexes, and channel lateral shifting are proved to be the most effective ones for a quantitative analysis of river changes. However, the calculation of these parameters is time-consuming, tedious and error-prone, even where made in a GIS environment. This work describes four shell scripts that perform fast and automatic calculation of the morphometric parameters and draw curves showing the variation of the calculated parameters along the entire channel development. The scripts are based on commands of the GRASS GIS free and open source software and, as input, they require a simple vector map containing the essential features of a river channel, i.e. bankfull channel limits and longitudinal and lateral bars.展开更多
Influence of structural and lithological controls of various drainage patterns and their stream orientations（for 2nd, 3rd and 4th order steams） were identified to evaluate the direction and controlling factors of dr...Influence of structural and lithological controls of various drainage patterns and their stream orientations（for 2nd, 3rd and 4th order steams） were identified to evaluate the direction and controlling factors of drainage network. To investigate the prospect of groundwater, hydrogeomorphological features of river basin viz. Mulki-Pavanje were identified and mapped. To evaluate the characteristics of the basin, different morphometric parameters（linear, areal and relief） were computed in sub-basin wise（SB-I to-VII）. The linear parameters suggest drainage network is controlled by geomorphology. The form factor（Ff）, elongation ratio（Re） and circularity ratio（Rc） suggest that the basin is in an elongated shape. The drainage density（Dd） indicates resistant/permeable strata under medium-dense vegetation with moderate relief. The areal parameters of the sub-basins（except SBI and Ⅲ） indicates moderate ground-slopes associated with moderately permeable rocks, which promote moderate run-off and infiltration. Drainage texture（T） of the whole basin indicates coarse texture while the SB-I, and Ⅲ showing an intermediate texture. The relief parameters namely ruggedness number（Rn） infers low basin relief and poor drainage density. To identify the most deficit/surplus zones of groundwater suitable weightages were assigned to the hydrogeomorphological units and morphometric parameters. The study reveal that the basin manifest that SB-Ⅲ shall be most deficit zone of groundwater, whereas SB-VII, VI and V are found to show increase in groundwater potentiality. Groundwater prospect area in this basin is estimated to be 7% area under poor, 44% area under moderate and 49% area under good to excellent. This paper demonstrated the potential application of geographical information system（GIS） techniques to evaluate the groundwater prospect in absence of traditional groundwater monitoring data.展开更多
文摘For the analysis of river evolution, the use of quantitative parameters can be quite useful in order to assess changes in the channel planform. Among the several parameters proposed by different authors in a number of papers, channel length and width, braiding and sinuosity indexes, and channel lateral shifting are proved to be the most effective ones for a quantitative analysis of river changes. However, the calculation of these parameters is time-consuming, tedious and error-prone, even where made in a GIS environment. This work describes four shell scripts that perform fast and automatic calculation of the morphometric parameters and draw curves showing the variation of the calculated parameters along the entire channel development. The scripts are based on commands of the GRASS GIS free and open source software and, as input, they require a simple vector map containing the essential features of a river channel, i.e. bankfull channel limits and longitudinal and lateral bars.
文摘Influence of structural and lithological controls of various drainage patterns and their stream orientations（for 2nd, 3rd and 4th order steams） were identified to evaluate the direction and controlling factors of drainage network. To investigate the prospect of groundwater, hydrogeomorphological features of river basin viz. Mulki-Pavanje were identified and mapped. To evaluate the characteristics of the basin, different morphometric parameters（linear, areal and relief） were computed in sub-basin wise（SB-I to-VII）. The linear parameters suggest drainage network is controlled by geomorphology. The form factor（Ff）, elongation ratio（Re） and circularity ratio（Rc） suggest that the basin is in an elongated shape. The drainage density（Dd） indicates resistant/permeable strata under medium-dense vegetation with moderate relief. The areal parameters of the sub-basins（except SBI and Ⅲ） indicates moderate ground-slopes associated with moderately permeable rocks, which promote moderate run-off and infiltration. Drainage texture（T） of the whole basin indicates coarse texture while the SB-I, and Ⅲ showing an intermediate texture. The relief parameters namely ruggedness number（Rn） infers low basin relief and poor drainage density. To identify the most deficit/surplus zones of groundwater suitable weightages were assigned to the hydrogeomorphological units and morphometric parameters. The study reveal that the basin manifest that SB-Ⅲ shall be most deficit zone of groundwater, whereas SB-VII, VI and V are found to show increase in groundwater potentiality. Groundwater prospect area in this basin is estimated to be 7% area under poor, 44% area under moderate and 49% area under good to excellent. This paper demonstrated the potential application of geographical information system（GIS） techniques to evaluate the groundwater prospect in absence of traditional groundwater monitoring data.
