Big Creek, draining into Lake Erie just west of Holiday Beach Conservation Area, was selected as the study watershed for the Clean Up Rural Beaches (CURB) program. The study determined fecal coliform and phosphorus loadings from upstream sources within the watershed using CURB algorithms and ranked the relative impact of these sources. In addition, the impact of the Detroit River and shoreline homes located west of Big Creek outlet, were assessed for their impact on water quality at Holiday Beach. A water and sediment sampling monitoring program was used to verify algorithm rankings. Improperly functioning septic systems within the watershed were identified from CURB algorithms as having the greatest fecal coliform loading of 1.04 x 1013 FC-yr-1, or 73% of the total 1.42 x 1013 FC-yr-1 loading. Sediment samples taken at the watershed outlet confirmed the presence of human fecal contamination. Similarly, elevated fecal coliform counts of human origin were measured at the Detroit River. However, the distance of the Detroit River from Holiday Beach was sufficient to minimize the impact of this source on water quality at the Beach, under normal lake conditions. Improper manure management practices accounted for approximately 23% of the total fecal coliform loading. CURB algorithms estimated winter spreading and spring/summer/fall overspreading to have significant fecal coliform loadings to Holiday Beach. Relatively insignificant fecal coliform loadings were associated with the other agricultural sources. Soil erosion within the watershed was identified as contributing the greatest phosphorus load of 7358.4 kg.yr-1, or 83% of the total load from the watershed as estimated by the CURB algorithms. High suspended solids and phosphorus concentrations measured at the watershed outlet confirmed sediment loading from upstream sources. A cost-effectiveness analysis determined that restricting livestock stream access, improving septic system operation and expanding manure storage facilities would result in the greatest fecal coliform load reductions. It was also determined that remedial measures directed at these sources will lower phosphorus loadings. Additional phosphorus loading reductions can be secured through the promotion of soil conservation practices. Water quality problems exist at other beaches throughout Essex County. The rural watersheds effecting downstream water quality have been identified and are considered to be eligible for the CURB Implementation Program.