An assessment of the nonpoint pollution from pastured livestock on a small stream watershed in Central Missouri was made. The stream flows through a state park which includes caves and sink holes. A computer was used to predict storm precipitation, runoff volume and dissolved oxygen (DO) levels in the stream during the summer months. Based on current land use, a cattle population of 500 head would be needed to drop stream DO levels below a minimum of 2. 0 mg/L. This also assumes that 20% of the livestock manure in the watershed reached the stream during runoff. Costs of fencing a 7m corridor on either side of the stream in the 2550 ha watershed was estimated at 76,875. Fencing of the entire corridor was not recommended. Proper management practices coupled with fencing of areas where animals tend to congregate along the stream would provide a high degree of stream protection.