The DEP plans to spend up to $125 million--with money coming from city
water and sewer fees--on cleaning up the Gowanus mess. Solutions include the
planned modernization of the flushing tunnel that draws water from New York
Harbor into the canal with "a much more robust, reliable pumping system" and
an upgrade of the sewage pump that directs sewage away from the canal and
toward the Red Hook treatment plant from the current 20 million gallons a
day to 30 million gallons daily. There might also be a "floatables vessel"
that would go around after bad storms and skim "floatables" from the surface
and there could be dredging of 750 feet of the end of the canal past the
Union Street Bridge to remove "sediment" left in the canal when raw sewage
flows into it. Underground retention tanks to hold storm runoff until it can
be handled have been dismissed as costing too much and requiring too much
land. (There was an early proposal to use the toxic parcel known as Public
Place for holding tanks, but the land is now supposed to become a mid-rise,
mixed use project with hundreds of units of housing.)
And the Gowanus has one heck of a wikipedia page. An accessible historical primer for you.