| Autor: |
Christina M. Richardson, Henrietta Dulai, Robert B. Whittier |
| Jazyk: |
angličtina |
| Rok vydání: |
2017 |
| Předmět: |
|
| Zdroj: |
Journal of Hydrology: Regional Studies, Vol 11, Iss C, Pp 178-193 (2017) |
| Druh dokumentu: |
article |
| ISSN: |
2214-5818 |
| DOI: |
10.1016/j.ejrh.2015.11.006 |
| Popis: |
Study region: Maunalua Bay, Oʻahu, Hawai’i. Study focus: We examined submarine groundwater discharge (SGD), terrestrial groundwater, and nearshore marine water quality in two adjacent aquifers (Waialae East and Waialae West) with differing land-use and hydrogeologic characteristics to better understand the sources and spatial variability of SGD-conveyed nutrients. Nutrient concentrations and NO3− stable isotope ratios were measured and integrated with SGD flux, land-use, and recharge data to examine SGD nutrient loads and potential sources in each aquifer. New hydrological insights for the region: Regionally elevated NO3- concentrations (166–171 μM) and δ15N–NO3− values (10.4–10.9‰) were apparent in SGD in the Waialae West Aquifer, an area with high on-site disposal system density (e.g., cesspools). Coastal sites sampled in the neighboring Waialae East Aquifer exhibited significantly lower values for these parameters, with δ15N–NO3− values ranging from 5.7–5.9‰ and NO3− concentrations from 43–69 μM. The isotopic composition of NO3− in SGD originating from the Waialae West Aquifer was consistent with wastewater. Modeled recharge data corroborated the NO3− stable isotope source designation. SGD emanating from Waialae West Aquifer was primarily influenced by two-component mixing of a wastewater source with low nutrient groundwater as wastewater effluent accounted for more than 4% of total recharge and 54–95% of total N and P loads in the aquifer. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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