A performance goal specifies what level of stormwater treatment must be achieved. The MIDS performance goals were developed to satisfy the legislation by determing how much precipitation must be retained on a particular site.
In April 2011, MIDS work group members agreed on a performance goal for new development: For new, nonlinear developments that create more than one acre of new impervious surface on sites without restrictions, stormwater runoff volumes will be controlled and the post-construction runoff volume shall be retained on site for 1.1 inches of runoff from impervious surfaces statewide.
In June, 2013, the MIDS work group members agreed on a performance goal for redevelopment and linear. Nonlinear redevelopment projects on site without restrictions that create one or more acres of new and/or fully reconstructed impervious surfaces shall capture and retain on site 1.1 inches of runoff from the new and/or fully reconstructed impervious surfaces. Linear projects on sites without restrictions that create one acre or greater of new and/or fully reconstructed impervious surfaces, shall capture and retain the larger of the following:
Mill and overlay and other resurfacing activities are not considered fully reconstructed. All projects shall first attempt to meet the volume reduction Performance Goal on site. However, if an applicant is unable to achieve the full Performance Goal due to site restrictions as attested by the local authority and documented by the applicant, the Flexible Treatment Options Approach shall be followed.