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October 19, 2020 Page 2 It is also important to note that some areas naturally flow away. from City. right-of-way, These natural flow paths discharge through private property. Public Culvert Conditions In addition to the several driveway culverts within.Scheuneman. Road Fiooding Area, there is one p.ublicaliy owned cross culvert that flows from east to west at approximately 3984 S.cheunerr an Road to 3909 5cheuneman Road. This. crossing is.just downstream of an area of flooding concern (6) identified in the. Scheuneman Road Flooding Memorandum. This particular area is not.a natural lowpoint and.does not have a natural flow. path away from City right-of-way. This crossing is.a plastic, approximately 12" -:15." diameter pipe and is in good .shape structurally. The upstream end of the crossing includes a flared end section. There was some minor seasonal debris accumulation but there did not appear to besedimentation or debris levels that would significantly restrict drainage however; the surrounding:area of the upstream crossing is surrounded by. mature shrub vegetation. Downstream of the crossing, there is. a riprap swale that extends approximately 80 feet downstream of the crossing towards the Gem Lake Golf Course, prior to. reaching the ultimate discharge point of Gem Lake. The rip rap swale appears to be more mounded within the bottom of the swale. This mounding may causing a.taiiwater condition to the culvert crossing. Limitations A hydraulics evaluation was not included in the Scheuneman Road Flooding evaluation or the city wide. culvert inspections. Therefore, it.should be noted that a culvert may not have adequate capacity based on hydraulics regardless of structural condition, submerged condition, sedimentation, orerosion condition. In addition, it is important to note that there are natural low areas throughout the City of Gem Lake. During snow, rain, or melt conditions, it is expected that.these areas will experience inundation. Recommendations and Next Steps The following recommendations from the Culvert Inspections Memorandum} still apply: • Increase Public Education: During inspections, a resident shared with the SEH inspector that they were not clear on whose responsibility it was to clean.and maintain their driveway culvert and roadside ditch adjacent to their property. it is recommended that the City. of Gem Lake increase the public education on the purpose of driveway culverts and. roadside d.itches,.the ownership of this conveyance, and the expectations fo.r the overall system. This may help residents better understand the overall system and encourage residents to keep.culverts and ditches clear from landscaping and vegetation, which may prohibit capacity: • Clean Out Sedimentation; it is recommended that the City initiate a culvert and ditch .clean out programi in the spring, fall, oras needed, to keep culverts and other:conveyance free from obstructions. In addition to the aforementioned recommendations it is also recommended that an elevation survey be completed at the cross culvert and upstream ditch with elevations .taken at the flowline and surrounding areas both up and downstream. Thisinformation should be use to complete a hydraulics evaluation of the area. This information will help the City to determine theappropriate size, and up and downstream flow line conditions necessary as to not exacerbate any area flooding concerns. Final Notes An additional site visit was completed following the City wine culvert inspections. It appears that there have been some recent culvert cleanings in the Scheuneman Road area.