AWWA ACE93099

Small aquifers, especially those of high permeability and with well-defined boundaries, lend themselves to alternative approaches to wellhead and groundwater protection. This type of aquifer is common in Hawaii, and many occur elsewhere. Development of a wellhead protection strategy for Hawaii is technically difficult because of the wide range of aquifer types and groundwater extraction units. Three protection approaches are currently being considered for Hawaii. The first approach involves the delineation of wellhead protection areas (WHPAs) around individual extraction units. This is the approach originally envisioned by the US Environmental Protection Agency (EPA) in its guidelines for delineation of WHPAs. We have identified appropriate delineation methods for the principal extraction units in Hawaii. The second approach involves delineation of aquifer protection areas (APAs), which are based on aquifer boundaries. The APA approach is conceptually superior to the WHPA approach by virtue of its comprehensiveness since the entire aquifer is protected, rather than just isolated areas surrounding the wellheads. The third is a time-phased approach that involves the initial delineation of WHPAs followed by an APA; that is, delineate WHPAs during the early stage of groundwater exploitation, and then switch to an APA at a later stage of exploitation near the sustainable yield of the aquifer. These approaches provide a choice, depending on the degree of protection desired and the extent of groundwater development in the aquifer.

Product Details

Published:

01/01/1993

ISBN(s):

0898677122

Number of Pages:

25

File Size:

1 file , 810 KB