Agenda - Public Works Committee - 06/16/2009

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CASE #~ CONSIDER IJRt\..INAGE RESOLUTIONS FOR GORHAMS SANDY ACRES By: Tim Himmer, City Engineer Bncl;.ground: A resident at 15130 Waco Street NW contacted the engineering deptlrtment last summer requesting assistance wlth localized flooding on his property; at times affecting his existing garage. Staff visited the site and reviewed the area topography to determine the extent of the problem. The property owner ,lives at the low point on the road and this street is constructed with ditch sections on both sides, so all runo ff from the contributing area drains to the ditch sections and flows to the low point. No culverts exist under drivew,\ys so each property along the roadway basically has some standing water during rain events until such time that it gc;ts deep enough in the ditches to overtop the driveways, or infIltrate into the ground. " The property owner's garage was constructed in a location that ;;lltered the existing drainage patterns of the area and damns the water at a k)w point located in his back yard. Runoff is notable to tind an overland path and t10w through to Xkimo Street. Even if water were able to tlow to Xkimo Street, as previously existed, there is a low point in the road surt11.ce along that roadway that would push the runoff problem onto ~mother resident. Therefore, staff considered this as a potential larger regional project as opposed. to a single drainage compl,lint. We started evalua.ting'u more all encomfmssing approach to handling this issue. Observations: . This area of the City was constructed in the late 1970' 5! and there is very little storm sewer that exists in the area. The ntral ditch sections do not appear to be well maintained and most driveways lack culverts that allow a contin1.1ott5 drainage path for runo ft'. A neighborhood open house was held at City Hall on April 29, 2009. Invites were sent to forty (40) property owners in the area located between Yakima and Waco Streets. Two individuals responded to the mailing; the resident that called in the initial concern and one other resident who claimed this item is being blown out of proportion. A few options htwe, been discussed for either a site specific fix, or a more regional solution. The property owner talked through all the improvements that he has undertaken to correct this standing water concern on his own (gutters and downspouts on his home, draintile, trench drains, and grading)! and he is now requesting assistance from the City to help resolve this issue. Staff has offered to provide information and calculations on the drainage area and approximate size of ~\ rain garden/infiltration basin that could be privately constructed along the common lot line with the neighbor to his south, who is open to assisting in a workable $Ol"ltion. Funding; This project could be eligible to utilize Stormwater Utility funds. Options: 1. Approach this as a regional problem and address runoff on a larger scale with storm sewer, easements! re~ditching, culvert installation, etc. Additional work would be required to accomplish this, and more residents would need to be included in the discussion related to a solution. Another item to consider under this scenario is whether to address this as a standalone project now, or wait for a reconstruction/maintenance project scheduled for the future. 3