Agenda - Council - 08/23/2011 - Laserfiche WebLink

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CC Regular Session Meeting Date: 08/23/2011 By: Tim Himmer, Engineering/Public Works 7. 2. Title: Accept Petition Requesting the Review of Drainage Concerns Around the 149th Lane NW and TH 47 Wetland Complex Background: With the recent significant rain events that have occurred throughout the summer, the City has received many calls from residents related to flooding concerns. The attached petition was received requesting that the City review the drainage problems in the neighborhood near 149th Lane NW and TH 47. This area is largely comprised of the RAMSEY MEADOWS neighborhood, which has 5 different subdivisions associated with it. This area was built around a rather large wetland complex, and easements were secured up to the 100 year flood elevation. The petition has 29 signatures from 28 properties in the area. Two signatures are from individuals that are different from what is currently shown as the property owner in Anoka County property records; but this could be due to recent sales, rentals, marriages or name changes, and/or a lag in time for data entry. If required, additional research could be conducted to verify those signatures in question. Staff received a call from the resident at 5410 149th Lane NW stating they had a considerable amount of standing water in their backyard. We conducted a site visit and reviewed the plat information for the property in question. It was determined that the backyard of all the homes along the east side of 149th Lane have a rather large platted drainage and utility easement at the rear of their property. This easement corresponds to the 100 year flood elevation of the surrounding water bodies. The City has received 2 - 3 100 year rainfall events over the past 2 months, which has contributed to elevated water tables and standing water in all ponds and wetlands citywide. Observations: Staff also reviewed all downstream pipes, culverts, and ditches to determine whether there may be an obstruction holding back the water. While no obstructions were found, it was discovered that the outlet pipe from the adjacent wetland that was installed as part of the TH 47 reconstruction several years ago may have been installed too high. We immediately modified that structure, and was able to provide some relief of existing surface water levels. It was also determined that the property owner had constructed some improvements in their backyard (retaining wall construction and/or grading revisions) that may have reduced some of the storage capacity in the area and compounded the situation. After reviewing the downstream system and witnessing that the water levels were consistent with what could be expected under extreme rainfall conditions, there was no further action proposed for addressing the stormwater situation in this area. The stormwater management system in this area appears to be functioning as originally designed. While residents in this area may not have experienced high water to this level in the past, doesn't mean that it won't occur under extreme conditions; which is what is currently being experienced throughout the City of Ramsey and many other areas within Anoka County. Recommendation: Staff recommends that the City Council accept the petition and provide direction on how they would like to address this matter. Funding Source: The review of this request to date has been completed using staff time. If additional work is directed staff will need to determine how much and from what source funding would need to be utilized to address the matter. Council Action: