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1330 Win Hentschel Boulevard, Suite 260 West Lafayette, IN 47906-4156 Phone: 765.448.6661 Fax: 765.448.6665

August 6, 2015 Michael Susong, P.E. Assistant City Engineer City of West Lafayette 222 N. Chauncey Avenue, Room 102 West Lafayette, IN 47906 RE: GM Development Childcare Facility TSC Project #9338.001 Michael, This letter is a request to be heard at the Tuesday, August 11, 2015 City of West Lafayette Board of Works meeting to hear and approve the variances from the Stormwater Technical Standards for the above referenced project. The variances requested are summarized as follows:

1. Variance from meeting the allowable release rates - A portion of the site must direct release to the existing Todd’s Creek ditch (which is planned to be eliminated with the State Street project). This portion of the site cannot be routed into the planned ponds. Also, in order to meet the allowable release rate, orifice plates smaller than those allowed in the Technical Standards would be required.

2. Variance from the channel protection requirements – the proposed dry ponds will provide some channel protection treatment. To fully meet the channel protection requirements, the ponds would need to hold the water back a certain amount of time. However, to do so would require orifice plates smaller than allowed in the technical standards. So, channel protection benefits will be realized, but not to the full extent based on orifice sizing limitations.

3. Variance from post-construction stormwater quality requirements – proposed dry ponds will provide some post-construction stormwater quality treatment. To fully meet the post-construction stormwater quality requirements, the ponds must hold the water back a certain amount of time. However, to do so would require orifice plates smaller than allowed in the technical standards. Therefore, post-construction stormwater quality benefits will be realized, but not to the full extent based on the orifice sizing limitations.

If you have any questions, please contact Josh Nixon (237-5250) or Jim Pence (237-5249) to discuss. Sincerely,

Joshua A. Nixon, P.E. Engineering Department Manager