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2004-04-16 Mud Lake Permit AppSEH April 16, 2004 Ms. Patricia Fowler Area Hydrologist MN DNR 940 Industrial Drive South, Suite 103 Sauk Rapids, MN 56379 Dear Ms. Fowler: RE: Albertville, Minnesota Mud Lake Outlet Permit Application, Mud Lake SEH No. A ALBEV 0314 32 The following items are in response to our phone conversation of April 12, 2004 about the outlet permit application for the proposed outlet structure, Mud Lake (86-26P), in Wright County. 1. Model results. I have attached a new Table 1, which reports the model results for the proposed Mud Lake culvert outlet. 2. Wetland permit. The Developer will be completing the wetland permit as a part of their planning process. 3. Culvert plan details. I have attached a typical detail sheet that shows what the outlet requirements will be for this culvert, including the apron and riprap. The road elevation at that location is proposed to be about 956.00-feet. With this elevation, and the modeled 100-year high water level of 947.5-feet, there is no predicted 100-year event flooding risk for the new road. 4. Channel clean out. The City has no plans to clean out the channel for any purpose, other than to keep the outlet channel free from vegetation that hinders water discharge. The Developer also has no plans to clean out any material from the channel, except for under the proposed roadway. Under the roadway they will clean out material that is not suitable as a road base. The Developer will be able to present their calculations for wetland material removal as they progress with the plans. At this time, they are waiting for the outlet permit approval before they finalize their plans. Please let me know if there is any further information that you need to submit the permit application. You can reach me at 320.229.4383 with any questions. Sincerely, Shannon Sant , E Project Engineer sesljmw c: Pete Carlson, SEH Jim Schulz, SEH Fran Hagen, Westwood Professional Services _ cAa projem\albev0314U-dnr-041504.doc Short Elliott Hendrickson Inc., 1200 25th Avenue South, P.O. Box 1717, St. Cloud, MN 56302-1717 SEH is an equal opportunity employer I www.sehinc.com 1 320.229.4300 1 800.572.0617 1 . 320.229.4301 fax Albertville Hydrologic Study Table 1 - Existing and Proposed Conditions XP-SWMM Modeling Results AALBEV0314.00 Wetland (Upstream of loth) 946.9 37 cfs 36" RCP 945.5 944.9 Wetland (Downstream of Mud) _- 36" RCP 946.2 945.5 Mud Lake 36" CMP 945.9 946.2 School Lake 36" CMP 946.2 946.7 Wetland (Upstream of loth) 947.1 46 cfs 947.5 20 cfs 36" RCP d 945.5 944.9 Wetland (Downstream of Mud) 36" RCP 946.2 945.5 Mud Lake 947.6 20 cfs 949.0 30 cfs 36" CMP 945.9 946.2 School Lake 36" CMP 946.2 946.7 33.6 cfs 946.9 3Rv .'*`.'.� Wetland (Upstream of loth) 36" RCP 945.5 944.9 Mud Lake 947.5 17.1 cfs 27" RCP 945.9 945.5 School Lake 949.0 30.4 cfs 36" CMP 946.2 946.7 Notes: s 1. All models run for 100-yr event. 2. Proposed Condition: Maintain existing NWL; Do not exceed a final discharge of 17.4 cfs. Mud Lk. and Downstream wetland are one pool; delete one culvert Starting water surface of Mud lake = 946.0 Tablel 041304 short ver.xls 4/15/04 z rt �i ' o O I- N J N 0 N z O 2 M O U W U O Er \ x r 4 1 0 14 vv CLASS III RIPRAP- REQUIREMENTS 2 1 O 12" TO 24" 6 CUBIC YARDS 27" TO 33" 12 CUBIC YARDS 36" TO 48" 18 CUBIC YARDS 5 X DIAMETER 54" AND UP 24 CUBIC YARDS (ONE CUBIC YARD IS OR SPAN APPROXIMATELY 2,800 LBS) PLAN GEOTEXTILE FILTER BLANKET SHALL EXTEND UNDER APRON NOTE FILTER BLANKET RE,______ UNDER RIPRAP OR 2 LAYERS OF 50OX "MIRAFI" FABRIC OR EQUAL a SEC. A -A SEC. B-B RIPRAP SLOPE VARIES RIPRAP LINER RIPRAP FILTER BLANKET LINER - CLASS III RIPRAP, D50- 9 IN. (MNDOT SPEC 3601) RIPRAP AT OUTLETS ALBERTVILLE, MINNESOTA STO-9b