Excessive amounts of two types of nutrients, nitrogen and phosphorus, are found in the Rouge River. This increased plant and algae growth robs the water of oxygen that fish and other aquatic life depend on to survive. If there are too many suspended solids in the water the water appears cloudy. This cloudiness is call turbidity. When the water has a high turbidity the sunlight that plants need to grow is blocked out, reducing the amount of plants.
Plants are important to add oxygen through photosynthesis and to provide food.
Stream Level and Flow A program to monitor instream flow rates has been implemented by the Rouge Project on a seasonal basis since 1993. Flow levels are continuously monitored with readings taken and recorded every 15 minutes. Networks of eight to 20 stations are established for a monitoring season, which typically lasts six to nine months. Flow rates are then calculated from the level data using rating curves that have developed at each station. The USGS develops the rating curves for the RPO using procedures that are consistent with the curve maintenance performed at their own gaging stations.