Topsoil Standard and Results of Topsoil Study

As the Board may recall, Staff had brought forth a discussion item several months ago related to the City's topsoil specification.  MnDOT's Standard Specifications for Construction (Spec Book) was recently updated and the topsoil specification referenced in City Code no longer exists.  That, coupled with the completion of the topsoil study conducted in North Commons, is prompting the need to revisit this topic to review what, if any, amendments may be necessary.  At the December meeting, the Board did, by motion, recommend that the Common Topsoil Borrow specification from MnDOT's 2014 Spec Book be considered an acceptable equal until such time that City Code was amended.  The Board also commented that they were interested in learning the results of the study once available. 

As can be seen in the executive summary, the current specified topsoil material is very efficient at retaining water and making it available for vegetation. Furthermore, the four (4) inch depth appears to be satisfactory (actually outperformed the six [6] inch depth specified soil). However, based on past discussions with the Board, and as noted in the recommendations section of the executive study, it may be beneficial to begin developing a menu of water conservation strategies that could be considered as part of a potential ordinance amendment. This would provide a developer/builder/home owner multiple options to achieve the goal of water conservation rather than strictly topsoil.  Although, it should be noted that the effectiveness of any option will be directly dependent on the property owners' knowledge and understanding of it.

Staff would like the Board to reaffirm their previous recommendation to accept the Common Topsoil Borrow specification from MnDOT's 2014 Spec Book as an acceptable alternative until such time that an amendment is processed.  Additionally, Staff would like the Board to begin discussing/identifying potential alternatives that may be incorporated into a potential amendment.  Note that it is Staff's intent to bring this topic forward for discussion with City Council at a future work session also to review the results of the topsoil study and seek direction on how to proceed.
 
The Parks and Assistant Public Works Superintendent will be in attendance to review the results of the topsoil study with the Board.

Motion to reaffirm recommendation to consider the Common Topsoil Borrow specification an acceptable equal to the current topsoil standard until such time that City Code is amended.