What water quality problems can be caused by impoundment stratification?

In the context of impoundment stratification, water quality concerns often arise specifically due to layered thermal stratification found in reservoirs. This stratification can lead to distinct layers where colder, denser water can become isolated from the warmer surface water. This phenomenon can cause significant changes in water chemistry, particularly leading to taste and odor issues.

When the deeper waters become anoxic, or low in oxygen, it can result in the release of dissolved metals like iron and manganese from sediments. As these metals are stirred back into the water column, they can cause taste and odor problems, especially as they become more concentrated when mixing occurs, such as during seasonal changes or turnover events.

This understanding underscores the importance of monitoring and managing stratification in impoundments to mitigate potential adverse effects on drinking water quality related to taste and odor, as well as higher levels of iron and manganese.