Major excavation works at the North Dam – the dam that faces Lebanon Borough – officially started earlier this week, the New Jersey Water Supply Authority (NJWSA) reports.
According to their latest project update, soils will be excavated from the downstream (north facing) slope of the embankment and stockpiled. Excavation will proceed from the crest (top) to the toe of the embankment.
“Stone and sand will be placed in the excavation to filter and collect any water that may seep through the embankment from the reservoir. The excavated soils and topsoil will be re-placed over the new sand and stone filter and the structure will look largely the same after construction,” said NJWSA.
The North Dam project area has four sediment control basins with diversion channels and outlet structures complete with skimmers, and overflow spillways.
Sediment control basins help to control soil erosion during construction. Each basin has been placed to capture runoff and control erosion and sediment from the embankment excavation itself or from a staging and stockpiling area.
Work at the North Dam will be ongoing through at least late 2021.
Concurrently, excavation and other embankment rehabilitation work at the Dike is ongoing and is expected to continue for at least several more months.
Work at the South Dam is expected to start later this year following completion of the Dike and the South Dam construction will continue throughout 2022.