As noted in the previous section, the second part of consent orders directed local governments to continue to implement the nine minimum controls required under EPA’s CSO policy. Several of these measures are directed toward reducing stormwater flows entering collection systems. As for CMOM, the committee recommends that similar actions be undertaken by all other municipalities that contribute sanitary sewer flows to the ALCOSAN system.

These measures might also include a wide range of alternative technologies, including urban retrofitting, low-impact developments, and recently considered ecological techniques that may offer potential stormwater flow reductions and are being tested in other communities.

3. Segregation of Combined Sewer Flows into Separate Sewers. In some portions of the combined sewer systems, it may be cost-effective to separate stormwater from sanitary sewage by constructing parallel collection systems. In some instances, construction of separate sanitary sewers may be appropriate. Segregated stormwater could then be treated and discharged through decentralized treatment systems, including wet and dry detention basins and other technologies discussed in later sections of this chapter. In some cases, the quality of stormwater runoff may be sufficient to allow rerouting of segregated stormwater through open channels with direct discharge to streams.

4. Real-Time Control of Combined and Separate Sewers. The use of RTC of flows in separate sanitary and combined sewers and stormwater conveyance systems should be investigated and evaluated as a means to reduce peak loading on centralized and decentralized treatment systems. The October 2003 consent orders required affected municipalities to install