Submarine Groundwater Discharge in a Stream-Dominated Embayment: Kahana Bay, Oahu, Hawaii
Located on the northeastern shore of O`ahu, Hawai`i, Kahana Valley is one of the island’s wettest watersheds. It has a continuously flowing stream, which introduces some challenges when conducting a submarine groundwater discharge (SGD) study. This study utilized a combination of established SGD research techniques, including high-resolution airborne thermal infrared (TIR) remote sensing and in-situ surveys for groundwater tracers (e.g. salinity, temperature, and 222Rn activities). This combination of techniques provided a quantitative understanding of the regional-scale and intra-daily variability of SGD in Kahana Bay. The total SGD flux was calculated to be 62,736 m3/day, approximately 63% of which was derived from a traditional Hawaiian fishpond on the bay’s eastern shore. This fishpond also had the highest nutrient concentrations in the bay. Remarkably, the SGD-derived nutrient fluxes to the bay were calculated be greater than or equal to those from Kahana Stream, ranging from ratios of 5:1 for TDP, 4:1 for TDN, and 1:1 for silica. Submarine groundwater discharge, therefore, has a significant influence on the bay’s geochemical budgets.
American Society of Limnology and Oceanography Ocean Sciences Meeting (ASLO)
Mayfield, K. K., Henrieta Dulaiova, Craig R. Glenn, Jacque L. Kelly.
"Submarine Groundwater Discharge in a Stream-Dominated Embayment: Kahana Bay, Oahu, Hawaii."
Geology and Geography Faculty Presentations.