Historical data referencing swale

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Zoning File #1970 October 12, 1994 Page 2 F - Hardcover Site Plan G - Hardcover Fact Sheets H - Gustafson Report 10/5/94 I - Grading and Drainage Plan J - Soil Boring Report K - Boring Map L - Preliminary Grading Plan Submitted with Preliminary Subdivision M - Street Elevation-Height Determination N - Side and Rear Elevations Description of Request Applicant proposes construction of a new residence that will require removal of approximately 450 cubic yards of poor soils and replacement with suitable granular material. Review Exhibit I. Applicant will store fill during construction to the southwest corner of the property. Review the grading plan, Exhibit I, changes in elevation must provide positive drainage away from structure directing drainage to ditch along the east side of property line. Note grade changes at the south and east side of garage on property to west. The plan would bring drainage to a catch basin that would drain via an underground tile across the rear yard of the subject property to the drainage ditch at the east. Review Exhibit H. The Engineer is concemed that the proposed grading plan will not provide adequate drainage or retention during heavy storms to protect lower level of garage on lot to the west. The proposed elevations will not maintain the natural drainage to the east. Gustafson recommends that applicant provide a modified drainage swale instead of the underground pipe. He notes that if applicant prefers the underground pipe system, that applicant's engineer provide the necessary hydraulic information to assure that it is designed to carry a 100-year storm frequency with a high water level at least one foot below the garage floor. The City will ask for a permanent drainage easement over the drainageway at a minimum width of 10'. Gustafson also cautions the building department in reviewing the foundation plans noting the results of soil boring #2 and advises of a potential settlement problem. The City is in receipt of a supportive letter from Mr. Terry Lindgren (owner of property to west) who supports the request to alter elevations on his property. Both Mr. Wold and Mr. Lindgren will be required to file for a joint land alteration permit from the City when final site grading commences next spring.