Discharge Stormwater to Stable Areas Stormwater discharging from road culverts can cause erosion, particularly of uncompacted or un-benched fill areas. Discharge stormwater from culverts on to stable ground, rock or other hard material. It may be necessary to add a flume or sock to the end of culverts to discharge stormwater beyond fill batters or other unstable areas. Culvert and Cut-off Spacing Install culverts or cut-offs at regular intervals to ensure stormwater does not erode the road surface. The number of culverts and cut-offs required will depend on the location of the road, local weather patterns and soil type. As a rough guide, in most cases culverts or cut- offs would be spaced at 100 – 150m intervals on a road or track with a gradient of 1:6. Flumed to clear unstable ll 9 1b0e0t wtoe 1e 5n0 c mulver ts