Animal Waste, Water Quality and Human Health

324Animal Waste, Water Quality and Human HealthUnited States (Francy & Darner 2003, Olyphant & Whitman 2004, Nevers &Whitman 2005, He & He 2008, Nevers et al. 2009). The USEPA has developed afreely available software package designed to construct site-specific MultipleLinear Regression (MLR) models for the prediction of FIO levels at recreationalbeaches. (Virtual Beach, online: http://www.epa.gov/ceampubl/swater/vb2/).Since 2009, the Wisconsin Department of Natural Resources (WDNR) and theOzaukee County Public Health Department (Ozaukee, WI, US) have partnered toimplement an operational “nowcast” system in Port Washington, WI, usingVirtual Beach which has proven more accurate than traditional monitoring(Mednick et al. 2011). Local operation of the “nowcast” model is tied to routinemonitoring and notification, and requires less than five minutes of HealthDepartment staff time per day (Mednick et al. 2011). Because beaches are unique,however, the predictive ability of “nowcast” models varies considerably frombeach to beach and is not necessarily dependent on the number or quality ofobservations available for model-building (Mednick 2009). Another VirtualBeach case study site (Red Arrow Park Beach, Manitowoc, Wisconsin) had only40 data points, yet the model FIO estimation was still more accurate than thepersistence model (binary open/closed decision based solely on FIO counts).Similarly, results of experimental models built for North Beach in Racine,Wisconsin, showed that beaches with very few exceedances can still besuccessfully modelled (Mednick & Watermolen 2009, Kinzelman 2011).Ultimately, a model’s predictive power – as measured by model sensitivity andspecificity, in addition to various goodness-of-fit measures – will determinewhether input data were adequate or the beach was a good candidate for modeling(Mednick & Watermolen 2009). With respect to MST, predictive models, byvirtue of associating increases in FIO density to prevailing environmentalconditions, may provide site-specific estimates on when, and potentially where,faecal loading to surface waters is likely to occur.9.3 SANITARY SURVEYSEmpirical evidence drawn from environmental observations may provide clues asto the “when” and “where” of contamination events, as well as inform associationsbetween ambient conditions and FIOs. Measured ambient environmentalconditions provide useful data for the development of tools such as predictivemodels. Well-crafted models have the ability to estimate FIO loading in realtime, but in order to execute a classification scheme for recreational or othersurface waters there must be a suitable mechanism to confirm pollutant sources;sanitary inspections are one such tool. A sanitary inspection, or survey, is anassessment tool designed to evaluate potential sources of faecal pollution