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Many Euclid residential areas were built with Combined Sewer systems. In the ‘CSs,’ storm and sanitary sewage is mixed for treatment.
Each Combined Sewer subsystem drains a small catchment. Each catchment has an Overflow point (CSO) at which a regulator dumps storm surges into an escarpment run sewer.
In this way, CSOs can deliver polluted stormwater directly to Lake Erie.
Euclid has just two remaining Sanitary Sewer Overflow (SSO) points. These will be eliminated in 2015, in compliance with the consent decree.
The EPA consent decree addresses ‘priority’ CSOs, those that activate (overflow) four or more times in a typical year. EPA regulates overflow. We need to manage catchment runoff.
Euclid has 8 priority catchments draining 312 acres with total annual overflow of 53.7 million gallons.
In order to meet the EPA mandate, the priority CSOcatchments must be the targets for ‘gray’ and ‘green’ stormwater infrastructure.
We must see the priority CSO catchments as localized landscapes on which ‘green’ can help solve the stormwater problem and enhance neighborhood quality of life.
In 2011, CT Consultants, Euclid’s engineering firm, wrote a Long Term Control Plan to address priority storm events.
Priority catchment overflow would be delivered to ‘gray’ equalization tanks near each catchment.
The stored overflow is later delivered to an upgraded wastewater treatment plant for processing.
Equalization tank location (red balloons), size and projected cost were as follows.
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CT priority catchment ‘gray’ solutions
Priority catchment equalization tanks ID basin location size MG $ M06/09 Erwine school lot 0.804 6.4307/12 Bir-Bee-Wal triangle 1.375 8.1608 Bab-NKPRR-Tungsten 0.009 0.6711 E 222-Coulter basin 0.012 1.1020 St. Robert church lot 0.240 4.4022 NKPRR-E 196-E 204 0.412 6.12
In 2013, Strand Associates and Human Nature (Strand) were hired to identify green stormwater possibilities within six priority CSO catchments. The goal was to eliminate or downsize the equalization tanks.
In five catchments, Strand identified areas in which new separate storm sewers could direct runoff to small bio-retention basins. These are called ‘green sub-catchments’.
Green sub-catchments can infiltrate significant volumes of stormwater thereby reducing the need for ‘gray’ infrastructure. As we shall see, the green sub-catchment solution is cost effective.
Particular features of Strand’s green sub-catchments are outlined in the following slides
Priority catchment ‘gray’ equalization tanks ID basin location size MG $ M06/09 Erwine school lot 0.804 6.4307/12 Bir-Bee-Wal triangle 1.375 8.1608 Bab-NKPRR-Tungsten 0.009 0.6711 E 222-Coulter basin 0.012 1.1020 St. Robert church lot 0.240 4.4022 NKPRR-E 196-E 204 0.412 6.12