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i 1�� May 10, 2007 �� Jay Johnson Zawadski Homes 4614 Churchill Street Shoreview, Minnesota 55126 RE: Variance Rain Garden requirement Dear Mr. ,Iotulson: C� We have had an opportunity to review the lot and proposed home at 397 S. O«�asso Blvd to detennine the size for the rain garden required as a result of your impervious area variance. From the infornlation you provided the additional hard surface is 682 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 infornlation applies in Minnesota. Here is some background 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 682 sf by 0.32 to get 218 sf. Your rain garden should be at least 218 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 witl�in 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 171 sf, a sandy soil one would need to be 102 sf. I have assumed clayey because I have no other information. If you have soils information, please provide it to us with your building permit to support the change in area for the rain garden. • See page 11-15 for construction infonnation 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 of the proposed rain garden be shown on the lot ��hen you come in for a building permit. If you have an i cerely, � a loo , P ons, p�lease contact me. City Engineer Phone: 651-792-7042 deb.blooin(a�ci.roseville.rnn.us CC: Bryan Lloyd �e311 F1riClell 2660 Civic Center Dri�=e ❖ Rose�ille, 1��linnesota 55113 651-792-ROSE ❖ TDD 651-792-7399 •.� www.ci.roseville.mn.us Rec��cled paper - 30°% post-consamer co�tent