Abstract

Horizontal well technology, borrowed from the oil and gas, river crossing, and utility line industries, has been increasingly applied in remediation of subsurface environmental problems. A horizontal well may be constructed to follow typical aquifer geometry, groundwater flow patterns, and contaminant plumes. In many cases, horizontal wells are the choice because contaminants are often found directly beneath buildings, landfills, and other obstacles to remedial operations. Another advantage of a horizontal well is its relatively high specific capacity, the discharge rate of the well divided by the drawdown. The specific capacity ratio of horizontal-to-vertical wells increases with decreasing aquifer thickness. Extraction of contaminated groundwater is often more efficient with horizontal wells; a horizontal well placed along the long axes of a contaminant plume can recover more mass of a contaminant at a given flow rate than a vertical well. In addition to enhancing a recovery system, horizontal wells can also provide additional information about a hazardous waste site that is not obtainable from vertical wells alone.