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� 1�� � August 3, 2007 Tom and Pam Gross 2613 Fry Street Roseville, Minnesota 55113 RE: Variance Rain Garden requirement Dear Mr. and Mrs. Gross: � We have had an opporiunity to review the lot and proposed improvements at 2613 Fry St. to determine the size for the rain garden required as a result of your impervious area variance. From the information you provided the additional hard surface is 350 square feet more than what is allowed by code. I have enclosed a copy of "Rain Gardens: A how-to-manual for homeowners" this resource will help you in the construction of your rain garden. It was originally written for Wisconsin, but the information applies in Minnesota. Here is some guidance for the design of your rain garden: • Page 9, Table 1: we do not have soils information on your site, as a result I assumed that your soil was clayey, so to determine the size of a 6 inch deep rain garden we multiplied 350 sf by 0.32 to get 112.0 sf. Your rain garden should be at least 112.0 sf in area. • Page 9 also discusses a simple soils test. I recommend that you conduct this test to better assist with sizing of this garden. Simply dig a hole and fill it with water, if the water disappears within 24 hours, the rain garden will be successful in your yard. • If you have silty or sandy soils, the size of this garden can be reduced. Page 9 also has some guidance on how to determine if the type of soil. A silty soil rain garden for your yard would need to be 87.5 sf, a sandy soil one would need to be 52.5 sf. I have assumed clayey because I have no other information. If you have soil borings, please provide it to us with your building permit to support any proposed change in area for the rain garden. • See page 11-15 for construction information for the rain garden. Be very careful to not compact the soils by driving heavy machinery on the bottom of the garden. • We will require that the location and design of the proposed rain garden be shown on the site plan and return a copy to Roseville Engineering Department before a building permit will be approved. I am available to meet with you on site if you have any questions. Sincer , Dean Findell Proj ect Coordinator Phone: 651-792-7046 dean.findell(a�ci.roseville.mn.us CC: Bryan Lloyd, Gerry Proulx, Deb Bloom 2660 Civic Center Drive ❖ Roseville, Minnesota 55113 651-792-ROSE ❖ TDD 651-792-7399 :• wwwci.roseville.mn.us Recycled paper - 30% post-consumer content