When you think about all of the green initiatives that surround us, you don’t expect to see a creek or river filled with green water. But that’s exactly what you might see if you are in the city of Wauwatosa or another community that is conducting dye water flooding this summer.
Dye water flooding (testing) is one of several proactive steps communities are taking to evaluate their sanitary and storm sewer systems in an effort to improve performance. It’s part of a green approach that prevents failing systems and basement backups.
R.A. Smith National has provided dye water flooding on more than 150,000 lineal feet of sanitary sewer for the City of Wauwatosa with plans to complete another 50,000 lineal feet by the end of the year.
The City’s goal is to quantify the total amount of clearwater that is infiltrating the sanitary sewer system, due to exfiltration from the storm sewer, and identify what methods are needed to remove the unwanted water. Recommendations to correct the deficiencies involve both public and private property repairs.
Dye water flooding is a process in which a non-toxic bright colored dye is added to a manhole or catch basin while the storm sewer system is being manually flooded with a hose. The manhole or catch basin is filled to street level to simulate a storm event that has reached the design capacity of the storm sewer.
The intense water pressure forces the dye into what may otherwise be invisible defects. The defects are identified with the use of closed circuit television (CCTV).
Once the process is complete, the dye water is released from the sewer system into a nearby creek. The data that is collected is analyzed and recommenda-tions are made for improving the system.
Dye water flooding is just one of several steps communities can take as part of a Sanitary Sewer Evaluation Study (SSES). An SSES is a formal program of investigation work encompassing dye water flooding, manhole and structure inspection, smoke testing, CCTV and flow monitoring. R.A. Smith National has extensive experience in conducting all of these steps in many communities throughout southern Wisconsin.
For more information regarding dye water flooding or conducting other aspects of a Sanitary Sewer Evaluation Study, please contact Chris Stamborski, P.E., 262-317-3337, project engineer in the Municipal Services Division at R.A. Smith National.