Parks Packet 04.19.23 - Laserfiche WebLink

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Draft Prospectus Document Page 3 07/07/2020 east to west of approximately 918 down to 908, slope grades are approximately 0.50%. This ditch is wide and shallow with an approximate width of 3-4 feet and a depth of 5 inches near the inlet. Near the ditch intersections this east-west ditch may get up to 3 feet deep depending on wet conditions. Water generally flows from the north part of the site to the south (to the east-west ditch) where it is then directed to the west. Water at the central and southern portions of the site flow to the west. Rice Creek Watershed District (RCWD) floodplain, FEMA floodplain, and FEMA floodway are all mapped within the site. Judicial Ditch 3 (JD 3) is present along the western boundary of the parcel and is also a DNR Public Watercourse (PWI No. M-059-008-005-002). There are a few easements (drainage and utility) nearby or within the property. The easement for JD 3 runs along the western property boundary. Adjacent to JD 3 is also a utility easement for a Metropolitan Council sewer line. There is also a powerline in the upper northwest corner and north side of the property with an approximately easement width of 60 ft. A few stormwater inputs into the wetland were encountered from surrounding infrastructure along the southeast. No apparent drainage easements were found for the inputs, but further investigation is needed during the next project phase. An open water area near the inlet at Hwy 61 appears to be a constructed stormwater pond, but the City and MnDOT do not have records of a BMP at this location. A vegetation meander survey was conducted during the 2022 growing season and documented a mostly monotypic plant community consisting mostly of invasive species like reed canary grass mixed with a few native sedges, grasses, and shrubs such as wool grass and red osier dogwood (Appendix C). Much of the area north of the east-west ditch is dominated by native sedges and shrubs. A wooded area at the south end of the site has both native and invasive/nuisance woody trees. Hydrology monitoring wells were installed in eight locations from July 2022 through October 2022 and did not show hydrology for 14 consecutive days or more within 12 inches of the soil surface. The antecedent precipitation for this site was considered normal, however the U.S. Drought Monitor showed that Minnesota experienced a drought during the 2022 growing season. At most well locations, the maximum elevation of the water table was about two feet below the ground surface, with water elevations closer to the ground surface near the east-west ditch. Results from hydrology monitoring, review of historic aerial photos, and soil survey information indicate hydraulic alteration due to the existing ditch system and or subsurface tile drainage. Drain tiles may be present within the site given the past agricultural use. A tile investigation will need to be conducted during the prospectus phase. Partial or full drainage of the wetland from alterations to site hydrology have created ideal growing conditions for invasive monotypic vegetation. The City has established the project’s restoration and rehabilitation goals from the results of the initial hydrology monitoring and vegetation survey. Photos of the existing conditions are included in Appendix D. Existing Wetlands: Describe any existing wetlands on your site, the wetland vegetation present, and any alterations to the wetland. Show the existing wetlands and important features on Figure 2. Several level 2 wetland delineations have been completed in portions of the property. Level 2 delineation was completed at: • the western boundary and northwest corner by WSB in 2021. • the southwest part of the site near the cemetery by WSB in 2020. • A level 1 boundary was completed for the remainder of the site in association with the delineation from 2021.