Estimates of water coming from surface water bodies (stream or lake depletion) are particularly necessary when siting drinking water wells near rivers or lakes with poor quality water. A finite difference model was used to analyze several hydrogeological systems characterized by large surface water bodies (i.e., lakes). A sensitivity analysis of lake width on lake depletion was made. MODFLOW model simulations show that, when lake width is more than about 2000 m, lake depletion becomes independent of its width indicating that rivers behave like lakes when width exceeds 2000 m. After about 600 modelling simulations and a best-fitting procedure a new empirical formula, allowing lake depletion to be estimated, is proposed. It expresses lake depletion as a function of various hydraulic and hydrogeological parameters, such as unit inflow to the lake, lake depth, distance between well and surface water body, filter length of the well, and pumping rate. The new formula can also be applied, with even larger approximations, to the estimation of stream depletion in cases of pumping close to surface water bodies less than 2000 m wide. The formula proposed here should be useful in deciding where to locate a pumping well and the appropriate length of its screen.
Pumping water wells near large surface water bodies
DI MATTEO, Lucio;DRAGONI, Valter Ulderico;
2008
Abstract
Estimates of water coming from surface water bodies (stream or lake depletion) are particularly necessary when siting drinking water wells near rivers or lakes with poor quality water. A finite difference model was used to analyze several hydrogeological systems characterized by large surface water bodies (i.e., lakes). A sensitivity analysis of lake width on lake depletion was made. MODFLOW model simulations show that, when lake width is more than about 2000 m, lake depletion becomes independent of its width indicating that rivers behave like lakes when width exceeds 2000 m. After about 600 modelling simulations and a best-fitting procedure a new empirical formula, allowing lake depletion to be estimated, is proposed. It expresses lake depletion as a function of various hydraulic and hydrogeological parameters, such as unit inflow to the lake, lake depth, distance between well and surface water body, filter length of the well, and pumping rate. The new formula can also be applied, with even larger approximations, to the estimation of stream depletion in cases of pumping close to surface water bodies less than 2000 m wide. The formula proposed here should be useful in deciding where to locate a pumping well and the appropriate length of its screen.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
