Agenda - Council - 02/24/2015 - Laserfiche WebLink

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Community Development Department Standard Operating Policy #001-15 Topsoil Specification Background In an effort to improve water conservation measures within the city, a topsoil requirement was implemented in June of 2009. The topsoil requirement has been amended several times over the years but the current standard is triggered whenever a building permit is issued for the construction of a new principal building and requires four (4) inches of topsoil applied to all disturbed areas not otherwise improved with impervious surfacing (roofs, driveways, walkways, etc.). Topsoil is defined as 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 consistent with the requirements of Table 3877-3 in MnDOT Specification 3877C (Premium Topsoil Borrow) as seen below: Table 3877-3 Premium Topsoil Borrow Requirement Minimum Maximum Material Passing 2.0 mm (#10) Sieve 95% -- Clay 10% 25% Silt 25% 60% Sand & Gravel 25% 60% Organic Matter 5% 15% pH 6.0 7.1 Soluble Salts -- 0.15 siemens/m 1.5 mmho/cm Issue In 2014, MnDOT published a new Specifications Book: Standard Specifications for Construction. This current edition does not include the Premium Topsoil Specification identified in Ramsey City Code. Thus, the definition of topsoil in City Code references a MnDOT Specification that no longer exists. Interim Solution The Environmental Policy Board (EPB) has reviewed the new topsoil specifications and has recommended that the City accept, at least for the interim time, material meeting MnDOT's Common Topsoil Borrow standard outlined in Table 3877-1 below. This was based on the fact that the allowable ranges for sand and organic matter within this specification most closely resemble the city's current requirement for these components. When a topsoil requirement was originally discussed by the City Council, it was these two components (sand because of the sandy soils present throughout much of the community, and organic matter because of its water holding capabilities) that were primary factors in selecting the current specification.