Recommended dimensions for stabilized berms. Source: MnDOT 2018 Standard Specifications
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Berm Type/Material Recommended shape Recommended base width Recommended height Recommended side slopes
Type 1 - compost Trapezoidal 5 feet 2 feet (minimum) 2:1
Type 2 - slash mulch Trapezoidal 5 feet 2 feet (minimum) 2:1
Type 3 - rock weeper system Trapezoidal 8 feet 2 feet (maximum) 2:1
Type 4 - topsoil Trapezoidal 7 feet 2 feet (minimum) 2:1
Type 5 - rock Trapezoidal 5 feet 2 feet (maximum) 2:1