What is "unidirectional" flushing?

In the Unidirectional Hydrant Flushing method, City staff isolate the flushing areas by closing pre-selected system valves. With the closure of these valves, water is directed to flow in one direction (“unidirectional”) and increase the velocity of the water in the pipes, thus more effectively removing particles and minerals from the pipe than simply operating hydrants without closing valves. After several years of use by the City, this method of system maintenance has proven to be an efficient and optimal way to maintain the quality of water within water mains. Unidirectional Hydrant Flushing requires additional staff on site to open and close valves and monitor residual pressures (water pressure remaining in the system while a fire hydrant is flowing), and the Water Division may be assisted by street paving staff since asphalt paving is weather dependent and cannot be completed during most of the winter months.

Show All Answers

1. Why is hydrant flushing necessary?
2. What is "unidirectional" flushing?
3. Who will be affected? What locations?
4. What impacts will residents and businesses see during the flushing?
5. What is the City doing to minimize the impacts?
6. Isn't this a waste of water?
7. Why don't we just capture the water and reuse it?
8. Are we polluting the river with the runoff?
9. If we have any additional questions, who do we call?