Consideration of request to construct retaining wall in Drainage & Utility Easement

The property owners at 15069 Helium Street NW are requesting that they be allowed to construct a modular block retaining wall along their east side lot line within the public drainage and utility (D&U) easement. They believe their side yard has been settling over time resulting in a steeper side slope that is getting more difficult to maintain and reducing support for their home's foundation walls. The property owner therefore feels that the settling of their side yard is putting their home in danger, and would therefore like to construct a retaining wall as quickly as possible.

City staff met with the property owners on their property to review and discuss the issue.  As can be seen in the attached pictures, the property owner had previously purchased and placed numerous retaining wall blocks on the surface of the ground along the bottom of the side slope along their easterly lot line. Staff also observed that their sod had never fully taken root and was therefore allowing water to run into the seams and between the partially-dead sod mat and the underlying soil. Therefore, whenever it rains the soil gets wet and the sod mat simply slides on top of the soil, resulting in a weak turf mat on the side slope. Based on this observation, staff believes this issue could most easily be resolved by removing the dead and decaying sod and establishing new turf, either seed or sod, and watering it adequately until it becomes firmly rooted.  The property owner did state that they plan to install an underground irrigation system this summer so this would help in establishing new turf and keeping it healthy.

It should be noted that during staff's site visit it appeared that the portion of the east side yard next to the garage is sloped at 3:1 or slightly steeper, making it difficult to maintain that portion of the yard.  Typically, the maximum slope used to allow for safe maintenance of turf is 3:1 as slopes steeper than 3:1 can result in riding lawn mowers tipping over when driven parallel to the side slope.

During the site visit staff explained that the city has an ordinance regulating allowable uses within public D&U easements, and that this ordinance prohibits the construction of permanent structures such as retaining walls within D&U easements. It was discussed that the construction of retaining walls can limit a neighbors use of their property due to the corresponding alteration of drainage patterns, grades and elevations. It was also discussed that D&U easements allow private properties to be served by utilities, both public and private, and that if a retaining wall is constructed over an existing utility it can impact the ability to cost-effectively access or maintain that utility. And conversely, if a new utility needs to be installed and a retaining wall exists in the easement area, the presence of a retaining wall may increase costs for utility companies, which are then passed on to users of the utility.

At the end of the meeting on site, staff informed the property owners that city staff do not have the authority to relax or waive the requirements of city ordinances.  However, staff informed them that their request could be presented to the Public Works Committee at their June 18th meeting and that the property owners would be welcome to attend to present their concerns and request. Then, based on the recommendations of the Public Works Committee, this item may be reviewed by the City Council at their June 25th meeting.  Since that time, the property owners have requested that a letter be provided to them stating the reason(s) why they are not being allowed to construct a retaining wall in the D&U easement.

Staff submitted an email to the property owners with the date, time and location of this meeting and invited them to attend to address the committee in person with their concerns.

The primary issue on the property appears to be the fact that much of the sod initially installed in the yard has died so the roots of the sod never fully took hold.  Staff therefore believes that the best solution would be for the property owners to establish new turf on their property, instead of constructing a retaining wall.

No funds are anticipated to be expended in relation to this item.

Staff recommends that the property owners request be denied for reasons stated herein.

The Public Works Committee is asked to deny the request of the property owners of 15069 Helium Street to construct a retaining wall within the D&U easement for reasons stated herein.