Outfall Channel Soil Erosion

In 1984 a diversion channel was constructed from Briscoe Ditch to the Brazos River. The diversion was requested by property owners along Briscoe Ditch who wanted to construct amenity ponds along the natural water course. The diversion channel experienced significant soil erosion during a rainfall event in 1985, and an erosion control structure was installed in 1986 to rectify this problem. A second structure was placed at the outfall of the channel, around 2001, to facilitate additional runoff from new development. An inspection of the structure in early 2012 indicated that the pipe installed in 1986 had deteriorated and needed to be replaced. Both the original structure and the one installed in 2001 would need to be replaced because of the proximity of the structures to each other. On May 12, the redesign was near completion when a 10” rainfall, within roughly 6 hours, destroyed the existing outfall structures and caused approximately 100,000 cubic yards of soil to be eroded from within the channel’s easement boundaries. Temporary erosion control measures were implemented after the May 12 event to prevent further loss of soil. This action was also meant to ensure that a bridge structure which crosses the channel close to where the erosion had occurred, remained structurally stable.