Modeling the influence of sea level rise on fecal coliform contamination in tidal estuarine system.

Wen-Cheng Liu, Wen-Ting Chan

Thursday 2 july 2015

17:30 - 17:33h at Asia (level 0)

Themes: (T) Hydro-environment, (ST) Impacts of pollutants on the water environment, Poster pitches

Parallel session: Poster pitches: 13G. Environment - Impact

Estuaries are the crucially vital aquatic resources in the world. They provide food resources and habit for ecologically and economically important fish and shellfish species, recreational regions, educational and scientific experiences, and other important ecosystem services. However, adverse impacts on the estuarine ecosystem by environmental perturbations (e.g., anthropogenic nutrient loading, land use change, hydrological modification) have been widely reported (McGlathery et al., 2007; Wild-Allen et al., 2013). Numerical water quality models have been used to assist the understanding of biological processes and assessment the influences of climate change on water quality conditions in aquatic systems (Paliwa and Patra, 2011; Long et al., 2011; Gao et al., 2013). However, little knowledge is focused on investigating the influences of climate change induced the change of freshwater discharge and sea level rise on local microbiological water quality. Sea level rise (SLR) is one of key factors affecting the future microbiological water quality in rivers and tidal estuaries. A coupled three-dimensional hydrodynamic and fecal coliform model has been developed and applied to the Danshuei River estuarine system in northern Taiwan for predicting the influences of sea level rise on microbiological water quality. The hydrodynamic and fecal coliform transport model was validated with observational water level, salinity distribution, and fecal coliform concentration. According to the analyses of statistical error, predictions of water level, salinity, and fecal coliform from the model simulation quantitatively agreed with the observational data. The validated model was then adopted to predict fecal coliform distributions between the baseline (with SLR) and different scenarios, including SLRs 0f 0.34 m, 1.05m, and 1.40m for the year 2100. The simulated results reveal that SLR would decrease fecal coliform distributions in the tidal estuarine system as a result of water level and water volume increasing. The maximum decrease ratios of tidal-averaged and depth-averaged fecal coliform concentration under the SLR of 1.40m would be 72.8%, 77.5%, and 73.2% in the Danshuei River-Tahan Stream, Hsintien Stream, and Keelung River, respectively. The SLR would have a positive impact on fecal coliform contamination in tidal estuaries.