2024-02-07 P & R Packet - Laserfiche WebLink

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Teresa Bender From:Mark Statz Sent:Thursday, December 21, 2023 11:51 AM To:Teresa Bender Cc:Paul Palzer Subject:RE: Prairie Restoration - Committee Concerns Teresa, Here are my responses to the quesons posed by the Parks and Recreaon Commiee, according to your memo. Concerns for underdrain and soils (was it there, proper depth retained, etc.) The original design of the infiltration/filtration basin (rain garden) included the scarification of underlying soils, and the amendment of existing soils. The soil amendment involved replacement of existing soils with poorly graded, granular material mixed with a small percentage of organic material to promote plant growth. The placement of granular soils and the scarification of underlying soils were done to promote infiltration. However, in Centerville, no matter how deep you excavate, you will continue to hit a layer of impervious soils. Therefore, an underdrain was also installed in the rain garden to ensure the stormwater retention time did not exceed 48 hours, as required by the watershed district. This requirement helps ensure plants which thrive in intermittently flooded areas will survive. The work contemplated by the proposal from Prairie Restorations does not intend to disturb the existing soils or underdrain in the rain garden. Concerns for plantings and whether they were the same as previous or different variety (if the plantings did not prosper previously, why plant again?) The original design documents were shared with Prairie Restorations. We asked them to review the documents and, if appropriate recommend new species or eliminate species from the original design. Their proposal is a blend of the original design and updated recommendations for plant diversification. We believe the gradual decline of the rain gardenÓs original plantings had more to do with the lack of professional maintenance, such as is being proposed by Prairie Restorations, and less to do with a flawed original design. In summary, the old design was good; we can make it better. But, all plantings need care from knowledgeable professionals to thrive. The goal, going forward, is to provide that level of care to our investment. Committee Member Seeley wanted to speak with the Conservation District ÐMitchÑ We did not reach out to the Anoka Conservation District to review the proposal. As I recall, the ACD was more heavily involved with the shoreline plantings than they were with the rain garden. We are happy to ask ACD to weigh in if Committee Member Seeley has not already done so. If we are not able to get in touch with the ACD prior to the meeting, the Committee could certainly make their approval contingent upon their review and approval of our plans. We are happy to answer any further questions the committee may have and are interested to know if the committee (and other volunteers) wishes to have a hands-on role in the work, as is outlined in one of the proposalÓs options. 1