However, in many areas water also comes from surface runoff, watercourses such as streams and rivers, or groundwater sources. Too much or too little water, or water at the wrong time, decreases agricultural production. The extremes, namely droughts or floods, can have disastrous effects. Farmers and other rural residents and industries must share this resource with fish and wildlife, and with those who enjoy the many recreational benefits of our rural landscape. The water resource is affected naturally over time in many ways.
Erosion alters the constituents carried by water.
Leachates reaching groundwater change its chemical composition. Also, climate change causes new runoff patterns. Many of these long-term changes can be speeded up or made worse by human activity. Such changes may be subtle and go unnoticed at first. It is important that the health of our water be monitored so we can understand the changes taking place.