Turbidity_Protocol_Details_0001.pdf

Protocol Details

All in-water work must comply with the Washington State Clean Water Act. This means;

1. At the 500 foot downstream station, if turbidity samples show an increase of more than 5 NTU above background level, equipment operator should be contacted immediately. In-water work should stop, and immediate action should be taken to correct the surge of turbidity. Work activities can commence when turbidity samples are compliant.

2. Before work activities start, background turbidity samples are taken two hundred feet upstream of the in-water work activities.

3. Turbidity samples are taken at a 500 foot downstream station from the work activities, and should be taken once every ½ hour if work activities are in or near a waterbody.

Turbidity samples should be taken immediately if excessive turbidity is observed. If turbidity samples are not compliant, follow step number 1 above, and continue sampling once every 15 minutes. Once compliant, continue once every ½ hour.

4. If extra staff is available, take turbidity samples 200 feet downstream. They can warn the sampler at the 500 foot station of excessive turbidity, watch project activities, provide feedback to staff at the 500 foot station, and should be able to provide easier contact to the equipment operator.

5. Samples can be reduced to once every two hours if staffs are certain the project activities will not increase turbidity levels.