The ratiooffecal coliforms to fecal streptococcus can help determine if the pollutants were from human or animal wastes. More than 4500 persons live within a mile of Lake Weatherford's shoreline and their septic tanks contribute roughly 267 pounds of organics and 49 pounds of nitrogen and phosphorous into the lake each day. Agricultural fertilizers add roughly 87 metric tons of nitrogen and 99 metric tons of phosphorus to the lake each year. Much of the fertilizer is applied in February and March when the most intensive rainfall occurs. Based on biological sampling, most of the non- agricultural pollutants originate from the southwestern portion of the lake.
Results also suggest that both animal and human sources are contaminating the lake.