When applying for your Construction Generic Permit (CGP) to discharge stormwater on construction sites, it’s important to know if dewatering will be required at any point during the project duration. Section VI of the Construction Generic Permit’s Notice of Intent (NOI) is where you may indicate about the need for dewatering.
Dewatering may be required due to accumulated water in trenches or excavation sites, areas with inadequate slope, locations with high rainfall, or if a site has a high water table. Dewatering is useful to keep a project on schedule and it can have environmental repercussions if proper Best Management Practices (BMPs) are not in place.
As previously stated, you may apply for a dewatering permit when applying for your CGP, or you may apply for it separately. When applying for your permit, it must be verified that the property is either not identified as a contaminated site and there is no contaminated site within 500 feet, or it is a contaminated site but documentation confirms the contamination has been remediated. This means that your dewatering permit only authorizes discharge of uncontaminated ground water. If you have any reason to suspect a discharge from dewatering on site has occurred, the permittee should contact the permitting authority immediately.
Not only should you discharge clean ground water but dewatering should not contribute to increased erosion and sedimentation or discharge turbid water. Regardless of the quality of the discharged water from dewatering operations, direct dumping of dewatering material into wetlands, lakes, creeks, rivers and into storm drains are not permissible unless you have been granted from proper regulatory agencies. All of these situations can be mitigated or avoided by implementing and maintaining proper BMPs. To reduce erosion, consider the volume and velocity of the discharge. If discharge is sediment-laden, utilize a control structure (like a dirt bag) or a vegetated buffer zone (like a swale). Storm drains and inlets should always be protected in active locations to safeguard sediment from entering.
If you are interested in learning more about BMPs for dewatering on your site, give the experts at KCI a call today – (888) 346-7779.
