03-26-2002 Planning Commission Meeting with Sibley Township

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ROAD SPECIFICATIONS WITHIN CITIES AND TOWNSHIP BY TERRY CURTIS-ANDERSON BROTHERS With the rapid growth in our communities throughout the lakes area,the need for defining road specifications is becoming increasingly more critical. With low interest rates and the need for housing in the area,2001 was the year for subdivisions and new plats. In 2001 Crow Wing County alone approved 15 new plats and or subdivisions for townships or unorganized territories producing some 183 new residential and or rural residential lots. Along with new housing developments come issues with proper right of way,easements,roads and storm water run off. Take a Sunday drive through many of our area townships and cities and you'll see varying standards or respectively, the lack of. Years earlier these cities,townships and counties didn't design roads and streets with the kind of growth the area is currently absorbing. Numerous cities and townships have begun to define and adapt standards to accommodate or help encourage smart infrastructure design and growth within their limits. Townships such as,Lake Edward in Crow Wing County, have adapted new minimum road construction/maintenance standards and in the absence of written county specifications properly adopted and in force on existing county roads,the townships minimum road specifications applies to reverted county standards. The Lake Edward township minimum road specifications are summarized as follows: • Sufficient clearing and grubbing shall be done to provide an adequate snow storage area for winter maintenance-the right-of-way shall be cleared. Stumps and debris must be removed from the easement area and all rocks larger than 3inches shall be disposed of or buried outside the limits of the roadbed. • A geotextile construction fabric shall be laid on the in-place unfrozen ground to provide support for the embankment and minimize the potential for failure of the fill. • The roadbed paved width shall be twenty-two(22)feet plus two(2)feet of shoulder on either side for a toatl width of twenty-six(26)feet. The roadbed shall be crowned 0.025 ft/ft laterally from the centerline to drain surface water and prevent standing water from saturating the roadbed. • Side ditch and embankment construction shall provide adequate roadbed drainage including installation of centerline culverts as required. Ditches shall have a minimum depth of two(2) feet below the edge of the shoulder. • Driveways within the road easements shall be a minimum of 25 ft wide. • Topsoil and seeding should be considered for all graded areas as a result of road construction to minimize erosion • The aggregate base shall be a minimum of six(6)inches of compacted class 5. • The driving surface shall be a bituminous mat twenty-two(22)feet wide and two and one-half(2 'h)inches in compacted depth. • Compacted class 1 aggregate shouldering shall be placed two(2)feet wide on either side of the bituminous surface. • Fast growing cities such as Crosslake have adapted aggressive standards not only for roads but also for many sub-developments. Crosslake has defined specifications for major rural roadways serving over 40 lots, rural roadways serving 26-40 lots,minor rural roadways serving 11-25 lots, lanes and accesses serving 0-10 lots,as well as,defining two classifications of drives serving from 0-5 and 6-10 lots. Additionally,the city has defined and recommended"dead end"treatments for city maintained roadways,such as,the preferrred"offset" cul-de-sac and the"t"type or branch type road conclusion. • In addition to elevation,ditching,righ-of-way, base and bituminous standards,Crosslake has developed the following minimum design requirements in road standards: • Topsoil: Minimum 4"compacted depth,MNDOT 3877 Type A Borrow • Turf establishment Seed Mix 125 lbs per acre Mulch Material Type 1(4): 1.5 ton per acre Mulch Material Type 5(4): 500 lbs per acre Dis anchoring is required unless hydroseeded