Treating runoff

A system configured to treat water passing through a catch basin, the system comprising:

• a filter extending from a first end portion having a first perimeter defining an opening to a second end portion having a second perimeter, the first end portion attached to an inlet of a catch basin and the second end portion removably secured to an inner surface of the catch basin at a location spaced apart from the inlet of the catch basin, such that the filter defining a continuous surface separating an inner portion of a cavity of the catch basin from an outer portion of the cavity of the catch basin;
• wherein the inner portion of the cavity of the catch basin is defined in part by the bottom of the catch basin.

A method of treating runoff, comprising:

• installing a filter in a catch basin in a position in which a first end portion of the filter is removably mounted to define an opening below the inlet of the catch basin, and a second end portion of the filter removably secured to an inner surface of the catch basin at a location spaced apart from the inlet of the catch basin, such that the second filter defines a surface separating an inner portion of a cavity of the catch basin from an outer portion of the cavity of the catch basin, wherein the inner portion of the cavity of the catch basin is defined in part by the bottom of the catch basin;
• and
• retaining some solid material within the inner portion of the catch basin as water passes through the filter into the outer portion of the cavity of the catch basin and flows out an outlet of the catch basin.