DETERMINING GROUNDWATER RECHARGE FROM IRRIGATION SYSTEMS FOR PRODUCTION OF BIOFUELS IN HAWAII
Grassland, Soil and Water Research Laboratory
2011 Annual Report
1a.Objectives (from AD-416)
Determine the rates of potential groundwater recharge in the sugar cane production system including seepage from irrigation canals and reservoirs. Seepage in these areas is critical for recharging aquifers that supply water to the Island of Maui. Quantifying the rates of recharge is needed to assess water supplies for potential biofuels production.
1b.Approach (from AD-416)
Categorize the existing 75 miles of irrigation canals by similar soils, geology, and slope and whether the canal is lined or unlined. Within specific sample areas of similar geology, slope, soils, and canal type (line or unlined), use geophysical methods to assess potential for seepage. In areas of potentially high seepage, install seepage meters to give more quantitative rates of water loss within the canal system.
The Navy's dependence on oil strains operational planning. Its focus is on securing a sustainable fuel supply. ARS research and models will help determine how best to manage natural resources to allow Office of Naval Research (ONR) sustainability in fuel supply while also promoting ecological services and the local economy in Hawaii.
Seepage under irrigation canals and water supply reservoirs has been identified as potential sources of water loss. An extensive literature review was conducted to determine available and appropriate field techniques to estimate seepage under canals and reservoirs. A resistivity method was tested on a representative reservoir and canal section to determine areas of active seepage. Seepage meters were designed to quantify seepage rates under areas identified as leaking using the resistivity testing. The seepage meters will be tested and applied next year on the HC&S (Hawaii Commercial & Sugar Company) sugar plantation in Maui.
The ADODR monitored progress through regular emails and phone calls with the collaborator.