Assessing the Feasibility of Soil Infiltration Trenches for Highway Runoff Control on the Island of Oahu, Hawaii

Authors

Martina Sobotkova, Czech Technical University, PragueFollow
Jaromir Dusek, Czech Technical University, PragueFollow
Ghasem Alavi, Swedish Meteorological and Hydrological InstituteFollow
Laxman Sharma, University of HawaiiFollow
Chittaranjan Ray, University of Nebraska-LincolnFollow

ORCID IDs

https://orcid.org/0000-0002-4863-2168

https://orcid.org/0000-0001-6511-9182

Date of this Version

12-12-2018

Document Type

Article

Citation

2018 by the authors

Comments

Water 2018, 10, 1832; doi:10.3390/w10121832 www.mdpi.com/journal/water

Abstract

The coastal waters of Hawaii are extremely important for recreation as well as for the health of the marine environment. Non-point source pollution from storm runoff poses a great threat to surface water quality in Hawaii. The State of Hawaii Department of Transportation (HDOT) includes 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 pollutant loads to streams and the ocean. In this study, the suitability of soils adjacent to highways on Oahu for the siting of infiltration trenches was examined. In addition to field surveys and in-situ tests, laboratory investigations on soil properties, infiltration experiments on undisturbed soil columns, and mathematical modeling of hydraulic functioning of the infiltration trench were conducted. Dissolved metal concentrations in highway stormwater runoff were observed to exceed the groundwater environmental action levels for all heavy metals tested, but the soils had high sorption capacity for these metals. The results of the simulations indicated that all the sampled Oahu soils, with one exception, would require less than two hours to drain a filled hypothetical trench. Therefore, these soils are suitable for construction of infiltration trenches as a possible BMP, even when clogging of soil is considered in the simulation.