TRANSMITTAL LETTER FOR BOARD MEETING OF DECEMBER 16, 2010
COMMITTEE ON ENGINEERING
Mr. Richard Lanyon, Executive Director
Title
Recommendation to grant a variance with respect to stormwater detention requirements for the Illinois Department of Transportation Maintenance Yard, Elk Grove Village, MWRD Sewerage System Permit Application No. 10-119
Body
Dear Sir:
The Engineering Department is in receipt of Sewerage System Permit Application No. 10-119, for sanitary sewer construction in conjunction with taking an existing Illinois Department of Transportation (IDOT) Maintenance Yard facility off a failing septic system and providing a connection to an existing public sewer. Stormwater detention for the project is required under the Sewer Permit Ordinance (SPO) and the Manual of Procedures for the Administration of the Sewer Permit Ordinance (MOP). However, the applicant is seeking a variance from such requirements.
To prevent or mitigate the adverse impacts of new development on flooding, effective January 1, 1972, the MOP was amended to add Article 6-4 which requires that in separate sewer areas, stormwater detention be provided for all sewer permit projects exceeding certain acreage limits. The intent of the detention requirements is that the rate of stormwater runoff from a site after its development not exceed the rate of runoff from the area in its undeveloped, natural state.
Article 6-4 of the MOP was further amended in 1998 by revising Section c(1), which now sets forth detention requirements specifically for redevelopments (i.e. totally or partially previously developed areas undergoing further development or redevelopment). In administering Article 6-4c(1), if a site undergoing redevelopment is already served by a sanitary sewer, and the site is part or all of a contiguous ownership totaling five acres or larger, then stormwater detention is required for the specific area being disturbed or redeveloped (e.g. a new or expanded building within the developed site). This requirement for stormwater detention also applies to areas that are unsewered. An existing facility and the adjacent property served by a septic system is considered an unsewered area. When an unsewered site connects to a sanitary sewer system, stormwater detention is required for the entire site.
In the case of the IDOT Maintenance Yard project, the proposed redevelopment will not result in an increase of impervious area. Therefore, the project will result in the same amount of stormwater runoff that currently exists. That runoff is directed to the stormwater collection system for Interstate 290 which is adjacent to the IDOT Maintenance Yard. It is in the best interest of the public and public health to encourage property owners to abandon septic systems whenever possible and not require construction of stormwater detention facilities in conjunction with connection to a sanitary sewer system.
In light of the Engineering Department’s opinion that the requested variance will cause no harm and will not violate the spirit and intent of the District’s Sewer Permit Ordinance, it is requested that the Executive Director recommend that the Board of Commissioners grant the variance requested in this case.
If further clarification is required, please advise the undersigned.
Requested, Kenneth A. Kits, Director of Engineering, WSS:MD
Recommended, Richard Lanyon, Executive Director
Respectfully Submitted, Frank Avila, Chairman Committee on Engineering
Disposition of this agenda item will be documented in the official Regular Board meeting Minutes of the Board of Commissioners for December 16, 2010