20230830 Environmental Board Packet Combined

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K:\020018-000\Admin\Docs\Memo\020018-000 Amelia Ditch Study Memo.docx Memorandum To: Michael Grochala, Lino Lakes Community Development Director Phil Belfiori, VLAWMO Administrator Diane Hankee, Lino Lakes City Engineer From: Earth Evans, PE, Director of Water Resources Tom Hoffman, Engineering Technician Henry Meeker, EIT Date: August 10, 2023 Re: Amelia Ditch Study WSB Project No. 020018-000 EXECUTIVE SUMMARY The Amelia Lake Ditch study was conducted with the goal of analyzing existing drainage conditions and proposing drainage improvements to the ditch draining to Lake Amelia within the City of Lino Lakes and the Vadnais Lake Area Water Management Organization (VLAWMO). The ditch has known flooding and other stormwater concerns in existing conditions. While these have been addressed in the past with localized private and public projects, the City aims to understand the problems along the entirety of the ditch and find solutions that best serve the surrounding properties Based on the existing concerns and anticipated future changes to the area, two phases of work are recommended. The short-term phase would consist of conveyance improvements to the section of the ditch currently causing the most problems for landowners. The long-term phase proposes more holistic improvements to the corridor that would occur alongside its eventual development. HISTORICAL BACKGROUND Based on the ditch alignment and surrounding topography, all signs indicate this was a constructed channel, not a natural stream. It is likely that the ditch was built and further expanded or modified based on agricultural needs in the surrounding areas. Where it is not serving direct surface flow drainage, the ditch also receives drain tile flows to aid in managing groundwater levels for nearby fields. This is supported by the broken remnants of a clay drain tile pipe found in the ditch during survey. All evidence indicates that this is and always has been a private ditch. No easement or maintenance records have been found supporting public ownership or management of the ditch. Maintenance has been conducted on a piecemeal basis depending on the needs and concerns of property owners along the ditch. Historical aerial images of the ditch have been found that date back to 1938. Th is oldest imagery appears to show the ditch with a slightly different and smaller alignment. However, certain stretches appear to be consistent with the current location. Imagery from 1957 shows the ditch with its current alignment. It appears much of the work bringing the ditch to its current condition occurred around this time. The spoil piles on either side of the channel appear in sharp relief and