We are a C57 licensed contractor: Approved to perform this work, dewatering and sealing wells
Dewatering Wells are used to control the water table and to remove any excess hydrostatic head pressure. This applies to substructures, deep excavation, vaults, pipelines, and various utilities when the ground water or water table is located above the target elevation or the level the contractor needs to perform his work.
Dewatering Wells Past and Future Risk; and the Exposure to You
In the past proper sealing and permitting in some areas, had not been addressed or taken seriously however the local agencies and state are beginning to pay more attention since ground water has become a commodity but only if it is clean.
Therefore, on every project we check in with the local agency to find out how they would like the temporary wells sealed upon completion. The state has their standards. However, in some cases the local agencies standards are more stringent so we generally will include the states state standards and then offer an alternate upgrade if the local agency standards are more stringent, to inform our client, and possibly keep them protected from future risk and exposure with regards to their site causing cross contamination issues.
The less likely you will have future risk and exposure if you follow the more stringent sealing means and methods, since you followed their procedures.
Dewatering Wells Abandonment; pressure grouting of well pipe with a eleven sack sand slurry and 5% bentonite, (per state of California guidelines) using trimie pipe to grout from the bottom up. In layman’s terms, we are ceiling a well to eliminate aquifer cross contamination. Decommissioning a dewatering well, pumping 27 sack neat cement before we remove it. This was the material requested by the local agency in this case, which was more stringent.
Some of our discharge plumbing from a small dewatering wells site in Sunnyvale. General was installing a new Vault, about 16′ below grade.
Water table was about 10′, so we set them up with a small dewatering system which worked fine to get the base sub grade nice and dry.
“Specialized Drilling Operation”