Starting in 1987 (through 1994), Peoria proactively undertook about $10 million (in 1980s dollars) in projects to reduce overflows. Projects included: Separating sewers in seven drainage basins by constructing either new sanitary or storm sewers to separate the combined flows; Constructing swirl concentrators at two locations to remove trash from overflows; Using a mile-long, 60-inch and 48-inch diameter sewer to store excess flows until downstream capacity is available in the riverfront interceptor; Installing gates to control the amount of flow discharged to the interceptor sewer and backflow valves to prevent the river from flowing into the interceptor sewers during flood conditions; Constructing treatment plant improvements and installing telemetry to monitor and report on sewer flows.
The benefits included reducing …
- The number of CSO locations is from 20 to 16.
- The average days of overflows from 40 a year to 28 a year.
- The overflow volume from an estimated 840 million gallons averages to 250 million gallons average in a typical year.
- The amount of trash discharging into the Illinois River.