Infiltration of Stormwater from Highway Operations to Reduce Coastal Pollution.

摘要

The coastal waters of Hawaii are extremely important for recreation as well as for the health of the marine environment. Runoff from the construction and operation of highways can be a source of pollution to coastal waters. Individual states in the US have established regulatory programs to protect surface waters for their designated uses. Protecting near shore waters is particularly important in the State of Hawaii where beach water quality is critical to the tourism-based economy. Diffuse pollution from storm runoff is found to have a great impact on surface water quality (Novotny, 1999; Kim et al., 2005). State and federal regulatory agencies are increasing their efforts to quantify and control the sources of non-point source pollution. Limited water quality monitoring data for storm runoff from the construction and operation of highway H-3 on Oahu are available (Wong, 2005; Presley, 2001; Presley 2002; Young and Ball, 2004; Young and Ball, 2005). Such data are not widely available for all areas of the state, although the Hawaii Department of Health (HDOH) and the Clean Water Branch are trying to develop and implement TMDLs for various streams. The current research was undertaken to obtain additional data on storm runoff water quality. The State of Hawaii Department of Transportation (HDOT) has included infiltration trenches as a Best Management Practice (BMP) option to reduce pollution caused by stormwater runoff. HDOT guidelines state that the implementation of BMPs is needed to reduce sediment and associated pollutant loads to streams and the ocean (State of Hawaii, 2007a, 2007b). In the standard trench design, highway runoff first passes through swales or buffer strips where most coarse materials and some contaminants are removed. This water then enters the trench and infiltrates through the trench bottom and sides, into the surrounding subsurface. While passing through the soil surrounding the trench, sediments and other pollutants (such as heavy metals, oil and grease, bacteria, and nutrients) are removed. This project attempts to identify potential sites for the construction of stormwater infiltration trenches on the island of Oahu.