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Engineering Review 'ox Den Acres City of Lino Lakes, Minnesota • Page 2 December 8, 2004 2. As a result of the plan revision, the site layout, grading, stormwater routing, and utilities have been adjusted in some locations. Revised drainage calculations have also been submitted. 3. Of the 50 acres, approximately 75% is upland or developable, while the remainder is pockets of wetlands scattered throughout the property or portions of DNR Wetland No. 565P, which borders the south and east edge of the properties. According to the information provided, the Ordinary High Water Level of the wetland is 893.0, and the Flood Zone limits have been indicated on the survey in accordance with the local Flood Insurance Rate Map, dated May 17, 1982. A ponding and flowage easement in favor of the City of Lino Lakes (Document No. 595478), corresponding roughly to the Flood Zone limits, is also indicated on the Plan. A Letter of Map Amendment (LOMA) will ultimately be required to perform the improvements as proposed. 4. A Resource Inventory Survey has also been prepared for this site. The site is generally undulating with mixtures of wooded areas, pasture, and wetlands. According to records of a Soil Survey by the USDA Soil Conservation service, the soils are generally fine sands and fine sandy loams with the exception of areas of muck in the vicinity of the lower flood plain areas. A Geotechnical Report as referenced above has also been provided and provides the following observations of note: a) Glacial outwash deposits of fine sand dominate the area. b) In the lowland areas, a black organic topsoil has developed, varying in thickness from 1 to 3.25 feet at the test pits. The total thickness of organic topsoil in the lowland areas was not explored. This should especially be taken into consideration where utilities and roadways traverse through lowland areas. c) The majority of test pits and test borings exhibited soil mottling which was used to assist in determining seasonal high ground water levels. Grading and Drainage 1. A General Stormwater Discharge Permit, Minnesota Pollution Control Agency (MPCA), will be required in accordance with the most current requirements of NPDES Phase II and State of Minnesota regulations. All NPDES regulations and requirements in accordance with the MPCA shall be adhered to, including submittal to the City of a Stormwater Pollution Prevention Plan (SWPPP). 2. Sedimentation and Erosion Control must be enforced at all times during the course of all grading and utility work. This includes the establishment of silt fence around all graded and disturbed areas, and the sweeping of streets on a regular basis, and as directed by the City. As per RCWD requirements, the grading plan must also be revised to specify inlet protection for the proposed catch basins. In the event the Contractor does not maintain erosion control as required, any costs incurred by the City as a result will be withheld from escrows or other monies due. It is strongly suggested that a note be added to all construction plan sheets (including grading, streets, and utilities) reminding the Contractor to address erosion control requirements. 3. The Grading Plan indicates that wetlands shall be replaced at a 2:1 ratio per requirements of the Wetland Conservation Act. The Plans also must be approved by the Rice Creek Watershed District (RCWD). A permit application has been submitted to RCWD (Permit No. 04 -039, dated March 12, -41- •