The order requires the City to construct and operate two Combined Sewer Overflow (CSO) retention tanks to control contaminated solids discharges. EPA?s order follows previous orders that EPA issued in 2014 and 2016 to require the City to design the two tanks. Controls to reduce CSO discharges and prevent other land-based sources of pollution, such as street runoff, from compromising the in-canal cleanup are a critical part of the site?s cleanup plan. Full-scale dredging of the canal commenced in November 2020. The order also requires the City to, among other things: 1) ensure that developers comply with municipal stormwater regulations within the Gowanus area to prevent additional sewer volume from impairing the effectiveness of the CSO tanks; 2) provide treatment for separated stormwater discharges; 3) perform monitoring of sewer solids discharges to ensure protection of the dredging remedy; 4) perform associated maintenance dredging, if determined by EPA to be necessary; 5) construct a bulkhead on City-owned property to prepare for the second phase of dredging work; and 6) adhere to an overall schedule for remaining tank design work and construction. The Region expects compliance with the order, which is estimated to cost $1.1 billion and take about 9 years to implement. The order acknowledges that the City is in significant noncompliance with the two prior administrative orders, which has delayed completion of certain CSO tank remedial design work and preparatory response