120.7 Drainage
Contents
120.7.1 Pipes and Culverts
Performance Expectation
Pipes and culverts shall be structurally sound and function as intended. They shall be kept clear and free of silt, debris and vegetation.
Performance Measures
Visual inspections will be conducted on randomly selected tenth-mile segments in the spring to determine if the pipes and culverts are performing as intended.
Performance Objectives
90% of the cross-sectional area shall be unobstructed and functioning as intended. No visible evidence of roadway settlement shall exist.
120.7.2 Inlets and Drains
Performance Expectation
Inlets and drains shall be structurally sound and function as intended. They shall be kept clear and free of silt, debris and vegetative growth.
Performance Measures
Visual inspections will be conducted on randomly selected tenth-mile segments in the spring to determine if the inlets and drains are performing as intended.
Performance Objectives
90% of the inlet opening and basin outlet opening shall be unobstructed, the unit shall be structurally sound, and the inlet grates and access covers (where applicable) shall be present and functioning as intended. No evidence of ponding shall exist.
120.7.3 Curbs and Gutters
Performance Expectation
All curb and gutter sections shall be structurally sound and function as intended. They shall be kept clear and free of silt, debris and vegetation.
Performance Measures
Visual inspections will be conducted on randomly selected tenth-mile segments in the spring to determine if the curbs and gutters are performing as intended.
Performance Objectives
100% of the gutter length shall be free of obstructions that would impede drainage flow. 90% of the curb and gutter area shall be free of structural distress. No evidence of ponding shall exist.
120.7.4 Ditches
Performance Expectation
Roadside, outfall, and median ditches shall be unobstructed and function as intended.
Performance Measures
Visual inspections will be conducted on randomly selected tenth-mile segments in the spring to determine if the ditches look good and are performing as intended.
Performance Objectives
90% of the cross-sectional area shall be unobstructed and functioning as intended. 90% of any paved ditch shall be structurally sound and no portion shall exhibit signs of undermining. No erosion or scour exceeding 12 in. deep and 10 ft. long shall exist in unpaved ditches. No evidence of ponding shall exist in unpaved ditches.
