#08 - Irrigation Alternatives for Oak Land Middle School

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A figure has been provided by the school district indicated which areas on the property are irrigated during the growing season. Irrigation Alternatives Identified: The 11/4/24 Irrigation Alternatives memo provided a basic assessment of the following alternatives for irrigation on site: 1. Private well – The school could continue to use its private well, however, the School District has indicated that this well is at the end of its useful life. Therefore, the School District would need to construct a new well for the purpose of continued irrigation of its property. 2. Stormwater Reuse – This would involve retrofitting the existing and proposed stormwater treatment systems. Currently, the school district uses infiltration basins which would be supplemented with underground systems with the new school addition. To facilitate reuse, the School District would need to reroute stormwater to a new storage tank with integrated pumping and mainline improvements to serve the existing irrigation. 3. Rose Lake – The school could construct a system to utilize water from the nearby Rose Lake. New irrigation improvements would be required in order to gather and then treat the water from this source prior to irrigating with it. 4. Municipal Water Supply – The School District would utilize its planned connection to the City’s water supply by connecting the school building, and therefore irrigation system, to municipal water. The School District has identified the connection to the Municipal water supply as its strong preference. This is due to the cost of either replacing its existing well or constructing the systems needed to reuse stormwater or pull water from Rose Lake. The School District has indicated that there are health concerns for stormwater reuse and pumping water from Rose Lake. The School District submitted a memo on February 28, 2025, so an analysis was not possible in this report. A verbal update and review will be provided by staff at the City Council’s March 4, 2025 meeting. Irrigation Reuse Requirements and Implementation in Lake Elmo: The City of Lake Elmo City Code does not require stormwater reuse for irrigation. However the City does allow for a density bonus when single family residential developments incorporate stormwater reuse into development plans. Over the last several years, the City has also seen stormwater reuse count towards Valley Branch Watershed District (VBWD) permitting requirements. As a result of focus on stormwater reuse in new development, the City of Lake Elmo has seen a number of new residential and commercial developments incorporate these systems into their design. Several recent examples include the Northstar and Wildflower residential developments, along with the Roers Lake Elmo Multifamily and Bridgewater Village multifamily and commercial developments. Over the past several years, the City of Lake Elmo has discussed whether it should require stormwater reuse. This issue is more complex than simply adding a new standard to the City’s ordinance. If the City chooses to revise its ordinances to require Stormwater Reuse, staff would need time to consider how this could be implemented the best. Factors for consideration include, irrigable area, impervious area, soils on a property, and other site specific issues along with considerations for the many different forms of development. Currently, staff are not aware of any municipalities in the Metro area that have this requirement. One reason is that there are likely to be certain properties or sites where stormwater reuse is not feasible or practical. One recent example is the At Home Townhomes project which did not use wet ponds, making stormwater reuse infeasible. Incorporating stormwater reuse is even more difficult for site expansions and could prove challenging depending on the amount of retrofitting required to a site. It is easiest to incorporate stormwater reuse