Intellectual Merit. A method of detecting the impact of sea-level rise on estuarine salinity will be developed. The method exploits high temporal resolution records of salinity, streamflow and tidal stage in order to develop statistical models of the influence of rivers and tidal currents on salinity. The models are then applied to long-term salinity observations of lower temporal resolution. Sea-level rise is the expected main cause of trends in the residual (observed minus modeled). The method will be applied to several mid-Atlantic estuaries, where data records are long and relative sea-level rise is about twice the global average. Modeling studies and scaling arguments suggest that the sea-level signal is well above instrumental error. What is uncertain and what makes the research exploratory is (1) the accuracy to which tidal and riverine influences on salinity can be quantified and (2) whether the instrumental records are of sufficient length and resolution.
Broader Impacts. Effective coastal management requires robust model predictions of estuarine salinity over the next 100 years. Models will be reliable only if they are calibrated with observations that clearly reveal a signal attributed to sea-level rise. This proposal is a first attempt to uncover such a signal. The method is general enough to be applied to any monitored estuary.
