There are 4 parts of a watershed. Those parts are surface water, rivers, lakes, and streams. Four human factors that affect watersheds are we develop the landscape, impervious surfaces, change in the natural water cycle, and dirty water.
The water was infected in April 2014 and went on for 4 years. The high lead in the water causing damage to the heart and kidneys. Children with elevated blood-lead levels may have risen from about 2.5% in 2013 to as much as 5% in 2015. It also caused Legionnaires' disease that killed 10 people and affected another 77. If they treated the pipes they could stop infection in the water. It was caused from the improper treatment that caused the lead aging pipes to leach lead into the water supply, leading to extremely elevated levels of the heavy metal neurotoxin.