What seasonal conditions cause yellow water?
In the Eagle Gorge Reservoir behind Howard Hanson Dam, water nearest the surface warms during the summer and colder water sinks to the bottom. Eventually, the reservoir becomes separated into layers by temperature. As oxygen is used up in the deeper water, it cannot be easily replenished and depletes. Low oxygen levels can cause iron and manganese in the reservoir’s sediments to dissolve into the water supply. When the iron and manganese react with chlorine and ozone at the water treatment plant, the minerals become even more visible in the water. Chlorine and ozone are required to help ensure the safety of the drinking water.
