38, 35, and 34 percent, respe tively. Sanitary surveys, which are emphasized by the SWTR, were used by percent of the watersheds and were ranked sixth in overall effectiveness. Use of formal written agreements with landowners in the watershed, similarly recomommended by the SWTR, were found Ommen only 16 percent of the watersheds and were one of the three least common control measures. Informal agreements with landowners were ranked as the least effective control measure by water utilitie
Water quality monitoring program
The survey gathered information on the monitoring frequency fo key water quality variables. Figure 3 displays theresults of the monitoring program inventory terms of the percentages of systems that monitor for a given water quality variable at any frequency,The block charts correspond to the four general categories of monitoring locations that were inventoried for the survey: finished water, raw water intake, reservoirs, and tributary streams. (A 100 percent scale is shown interpretation of the frequency distribution) The bar heights (and coresponding percentages) for the rows labeled reservoirs and tributary streams" have been adjusted to account for only those systems that have the portunity to monitor in these locations (i.e., the few systems that obtain wate from intakes on large rivers were elimnated from the analysis)
The analysis found that monitoring some frequency (e.g.. daily, week monthly) for a given water quality variable occurs in about the same relative proportion for the four monitoring location categories. The basic physical wat quality variables (turbidity, temperatur and pH) are the most commonly monitored variables in all locations.
The survey also highlighted a number of s in raw water monitoring on a nationwide scale. For programs example, only 60 percent of the system monitor reservoirs for key, easily measured variables such as turbidity and pH and even fewer (about one third of th systems monitorthese variables in the tributary streams. Monitoring for two the basic indicators of eutrophication