Abstract
To meet European Water Framework Directive requirements, data are needed on faecal indicator organism (FIO) concentrations in rivers to enable the more heavily polluted to be targeted for remedial action. Due to the paucity of FIO data for the UK, especially under high-flow hydrograph event conditions, there is an urgent need by the policy community for generic models that can accurately predict FIO concentrations, thus informing integrated catchment management programmes. This paper reports the development of regression models to predict base- and high-flow faecal coliform (FC) and enterococci (EN) concentrations for 153 monitoring points across 14 UK catchments, using land cover, population (human and livestock density) and other variables that may affect FIO source strength, transport and die-off. Statistically significant models were developed for both FC and EN, with greater explained variance achieved in the high-flow models. Both land cover and, in particular, population variables are significant predictors of FIO concentrations, with r2 maxima for EN of 0.571 and 0.624, respectively. It is argued that the resulting models can be applied, with confidence, to other UK catchments, both to predict FIO concentrations in unmonitored watercourses and evaluate the likely impact of different land use/stocking level and human population change scenarios.
Highlights
Introduction―programmes of measures‖ to manage point and diffuse sources of faecal indicator organisms (FIOs) that could cause non-compliance of bathing and shellfish-harvesting waters with microbial standards [1,2]
Under the Water Framework Directive (WFD) EU member states are legally required to design―programmes of measures‖ to manage point and diffuse sources of faecal indicator organisms (FIOs) that could cause non-compliance of bathing and shellfish-harvesting waters with microbial standards [1,2]
To increase the robustness of the modelling, only sites that meet the following criteria have been included: (1) catchment area ≥ 5 km2; (2) < 50% of land within the subcatchment is located upstream of lake and/or reservoir outlets; (3) FIO data available for ≥ 5 samples taken under the flow conditions being modelled; (4) river discharge records available; and (5) land within the subcatchments had not been subject to programmes of measures aimed at reducing
Summary
―programmes of measures‖ to manage point and diffuse sources of faecal indicator organisms (FIOs) that could cause non-compliance of bathing and shellfish-harvesting waters with microbial standards [1,2]. To meet this requirement, data are needed to define FIO concentrations and fluxes in individual rivers and streams so that the magnitude of the problem can be assessed and more heavily polluted waters identified for potential remedial action. Kay et al [3], for example, report an increase in geometric mean (GM) faecal coliform (presumptive Escherichia coli) (―FC‖) export coefficient for 205 UK rivers and streams from 5.5 × 108 cfu km−2 h−1 at base flow to. FIO concentration data are lacking for many UK watercourses, and, even for those that are routinely monitored, there is often poor characterisation of high-flow conditions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
