Significant chloride increases at many sites were probably due to effluent from STWs that was less dilute than previously because of low flows, road salt stored near river banks, and in some cases industrial effluents from meat-processing factories and water softening plants ([13], pers. comm.). Low flows, such as those during 1993–1997, allow for more algal growth, which could have stripped SRP from the water, accounting for the positive relationship between flow and SRP shown in Fig. 5.