HYDRAULICS OF HORIZONTAL AND SLANTED WELLS IN WATER TABLE AQUIFERS

New analytical solutions for evaluation of the drawdown near horizontal and slanted wells with finite length screens in water table aquifers are presented. These fully three-dimensional solutions consider instantaneous drainage or delayed yield and aquifer anisotropy. As a basis, solution for the drawdown created by a point source in a uniform anisotropic unconfined aquifer is derived in Laplace domain. Using superposition, the point source solution is extended to the cases of the horizontal and slanted wells. The previous solutions for vertical wells can be described as a special case of the new solutions. Numerical Laplace inversion allows effective evaluation of the drawdown in real time. Examples illustrate the effects of well geometry and the aquifer parameters on drawdown. Results can be used to generate type curves from observations in piezometers and partially or fully penetrating observation wells. Computer software WHI is written to calculate drawdown in real time and to generate type curves. The proposed solutions and software are useful for the parameter identification, design of remediation systems, drainage, and mine dewatering.