Flow and filtration into HDD wells in river bottom sediments for potable water.

摘要

Horizontal Directional Drilling (HDD) may be used to pre-treat surface water for drinking water provision. Placed in the saturated sediments beneath rivers, they could serve as an alternative to the intake structures commonly used by water treatment plants, using the sediments as filters. Pilot-scale field tests were conducted in 2000 and 2001 to estimate the improvement in water quality achieved from such a system. These tests indicate that turbidity can routinely be reduced by 75%–85%, and particle counts by 80%–90%.; Finite-element models were then used to evaluate the flow rate of water produced by such horizontal wells. The model results were examined for their sensitivity to well length, diameter, depth, and the aquifer hydraulic conductivity. The effect of pipe hydraulics was included to examine well length optimization. Numerical model results generally agree well with published accounts of horizontal collector well and infiltration gallery performance.