Geosyntec has provided consulting services to We Energies on several sediment removal projects at their Port Washington Generating Station (PWGS), a 545-MW power generating facility on the shore of Lake Michigan. Sediment removal was critical to plant reconstruction activities and continued operations. For an intake and discharge tunnel sediment removal project, the selected removal method was to isolate tunnel segments, dewater and solidify the sediment in-place, and dispose of the sediment in an off-site landfill. For an emergency intake tunnel sediment removal project, the selected removal method was to remove sediment from the tunnel, mix it with a polymeric additive within geotubes to facilitate the dewatering and solidification process, and dispose of it in an off-site landfill.
Geosyntec's Scope of Services
Intake and Discharge Tunnel Sediment Removal: Geosyntec performed pre-removal sediment sampling and reviewed tunnel inspection data; assisted We Energies in developing the sediment removal plan; prepared bid documents; coordinated sediment removal contractor, discharge water filtering contractor and disposal facility; performed construction oversight and performed field discharge water and sediment paint filter testing; reviewed contractor submittals; and prepared construction documentation report. We worked with the disposal facility to develop an acceptable field solidification testing program to ensure that the solidified sediment met landfill acceptance criteria. This program allowed sediment to be hauled directly to the landfill without temporary on-site storage. Geosyntec also developed a water suspended solids field testing program to ensure that the discharge met WDNR permit criteria. This program allowed the Contractor to remove water from the active tunnel segments and discharge it continuously.
Emergency Intake Tunnel Sediment Removal: Geosyntec's pre-removal services have included procuring inspection bids and coordinating diver inspection work; compiling and evaluating inspection data and determining distribution and volume of sediment; performing sediment sampling; assisting We Energies with developing the sediment removal plan, including assessment of removal, dewatering, and solid and water management options; assisting We Energies with WDNR dredging permit including evaluation and correspondence regarding polymer toxicity/dosage and discharge water quality criteria; and preparing sediment removal bid documents and procuring bids. We are currently coordinating and assisting in the oversight of filter tube containment pad construction. We will provide oversight of the diver-assisted dredging, filter tube dewatering and associated discharge; review contractor submittals; perform discharge monitoring pursuant to the WDNR permit; assist in the coordination of dewatered sediment disposal; and prepare a construction documentation report.