Agenda - Council - 04/28/2009 - Laserfiche WebLink

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CASE # L/ ADOPT ORDINANCE ESTABLISHING TOPSOIL REQUIREMENTS By: Tim Rimmer, City Engineer Chris Anderson, Environmental Coordinator Background: Ramsey has been identified as one of the largest users of non-consumptive water in the metro area. In an attempt to reduce the quantity of water used annually, the City has considered and implemented various conservation measures over the years. There have been several iterations of a topsoil requirement considered by both the PublIC Works Committee and the Environmental Policy Board, dating back to January of 2006. At the July 15, 2008 Public Works Committee meeting, staff was directed to prepare a topsoil ordinance requiring a minimum of four inches of topsoil, meeting MnDOT specification 3877.2C (premium topsoil borrow), in landscaped areas of all new developments (residential and commercial/industrial). After further research, staff modified the recommended topsoil specification slightly, to more specifically address the soil conditions found in Ramsey, and brought it before the City Council for introduction on January 13, 2009. At that meeting Council made additional revisions to the proposal and requested that it be brought to a work session to resolve any issues prior to adoption, which was done on April 7,2009. At that meeting samples were presented, along with a price break down of each, and aJist of suppliers that could produce the material. It was determined by the Council that instead of producing a specific blend meeting MnDOT specifications, we should be looking to define in more general terms the City's requirements for topsoil. Observations: The sandy soils found throughout the City have low water retention capacity, thus large quantities of water are used each year for irrigation. Generally speaking, the topsoil in the City consists of silty sand with minimal organics and clay content. Therefore, establishing a. topsoil requirement should increase the soil moisture holding capacity of the soil, due to the higher amounts of organics required. Based upon investigation and discussions with some local suppliers, the additional financial impacts of this proposed ordinance would equate to approximately $1,000 for.a standard % acre residential lot, and $2; 200 per acre for an industrial/commerciallot. This new topsoil requirement would be triggered by the issuance of a building permit for new construction of a principal structure. The benefits realized from.requiring topsoil would include reduced demand for non-consumptive water, improved recharge of aquifers, and lower utility bills for residents as a result of less frequent watering. . The proposed ordinance requires the installation of a minimum of four (4) inches of topsoil over all exposed areas not improved with buildings and paving, excluding natural areas that are left undisturbed. The topsoil requirement would apply to any lot, in any zoning district, being improved with the construction of a principal building. From direction at the April 7,2009 work session the revised topsoil definition is proposed to be: "Black dirt composed of unconsolidated material, largely undecomposed . organic matter that is a suitable foundation for vegetative growth. The composition of the topsoil shall include a well balanced medium consisting ofthefollowing: · A maximum sand/silt content of 20% · A minimum organic content of 35% · A pH between 6 and 7 · Removal of all rocks in excess of 3/4" -163-