Seepage from old meandering Pleistocene river channels continue to feed into the left bank of Canal A (primary irrigation canal on the DMAD system) resulting in sand boils, nearly constant seepage into the canal and destabilization of the left canal banks in close proximity to DMAD Dam.
Working in concert with Bowen Collins & Associates engineers, we designed a canal-lining system through this reach consisting of the following elements:
- Removal of old riprap (primarily old concrete ditch lining materials and loose, sloughed materials).
- Construction of a filter/drain system that would pipe seepage water away from the left canal bank and into the dam downstream toe drain.
- Stabilization/replacement of canal bank and bottom materials, and placement of a geotextile-bonded geomembrane up to the canal high-water level.
- Placing riprap bedding and riprap to dissipate water energy coming through the outlet works and to minimize bank erosion adjacent to the dam.