Researchers used a computer program to study water quality in the Mad River Basin in Ohio. They looked at fecal coliform and nitrate levels in the water from 1999 to 2003. They found that some areas had too much fecal coliform, especially near Springfield. Nitrate levels were also high in agricultural areas. By making changes like fixing septic systems and keeping cattle away from streams, they were able to reduce fecal coliform levels by 73%.