ABSTRACT
Horizontal wells installed using horizontal directional drilling technology are a new consideration for environmental remediation and water supply problems. Unfortunately, their implementation is being hindered by a lack of unbiased performance assessments of field installations. To provide some information regarding the performance characteristics and limitations of this new technology, a field investigation focussing on the response of an unconfined aquifer to groundwater extraction from a horizontal well was conducted. A monitoring network comprised of over 85 distinct observation points was installed in the aquifer in the neighbourhood of the horizontal well. For comparison, a fully-screened vertical well was also installed. Both short-term and long-term pumping tests were performed. The results from this investigation suggest that at distances greater than 80% of the screened length of the horizontal well, the aquifer response is identical for extraction from either a horizontal or vertical well. The nature of the response in close proximity to the wells, however, is distinctly different and may have significant implications to remedial applications.
