02-19-2002 Planning Packet - Laserfiche WebLink

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Native shrubs will also be planted in the mitigation site to provide additional cover and diversity (Appendix B, Sheet 2). Shrubs will be planted in a random pattern within the designated areas and will be a mixture of red osier dogwood (Comus stolonifera), eldc»berry iSambitciis canadensis), and several willow species (SrlU exigua, 5. bebbiana, S. amygdaloides, and S. discolor). Nannyberry (Viburnum Icntago) may also be used to increase diversity if available. Willow species should be concentrated around the existing drainage ditch to provide maximum erosion control. Cuttings from the various willow species and red osier dogwood should be used in and around the banks of the drainage ditch to provide a cost-effective method of revegetating the exposed banks. Cutting should be collected from native stock and kept moist until they are planted. The few red osier dogwood on site may be salvaged and transplanted or used for cuttings. If thej arc transplanted, care should be taken that buckthorn is not incidentally transplanted as well. Container plants should be used throughout the remainder of the site. Erosion Control Appropriate erosion control piocedures will be used for the construction of the mitigation site and the storm water treatment pond. These methods are shown in Appendix A. Appendix B Sheet 3, and detailed in Appendix G. Silt fencing will surround the entire project site and the existing drainage ditch. Silt fencing will also be placed in the ditch to collect any additional material that may enter. Construction will also be timed so that no activity wilt be done if the site is inundated or flooding. Wood fiber blanket will be placed in the mitiaation area w’here water mav be flowinc into or out of the site. W ^ ^ These areas will also be planted with dense willow shrubs to provide rapid soil stabilization. Summary of Wetland Replacement The impacts from the creation of a new fire station will require the creation of 17,180 feet^ (0.39 acres) of wetland as a combination of new wetland or permanent upland buffer. The construction of the mitigation site, upland buffer, and storm water treatment pond will create 15,033 feet* of New Wetland Credit fN'WC) and 14.584 feet* of Public V'alue Credit. These credits are summarized in Table 1. Public Value Credit is composed of 12,605 feet* for upland buffer and 1,979 feet* for the storm water pond (The normal pool area of the storm water pond is 2,638 feet*, of which 759c can be claimed for credit). The City of Orono has an approved storm water management plan, which is a requirement to allow PVC credits from storm water ponds to be allowed. Under the WC.A, replacement of wetland impacts can be done as a combination of N^'C and PVC. We propose to use 8,590 feet* of the new wetland and 8,590 feet* of the upland buffer area to Minnehaha Creek Watershed Oislrtci Permit Application City of Orono, Minnesota A-LONGL0204.00 Page 11