Jun 29, 2018

Construction Considerations

Understanding storm water management compliance on commercial construction sites

Understanding storm water management compliance on commercial construction sites
Understanding storm water management compliance on commercial construction sites

Planning for storm water management as part of construction project management on commercial sites can help prevent unanticipated costs and the need for additional contractors on a project.

The party responsible for planning and managing storm water permitting and compliance for a construction project should be determined well in advance of breaking ground. Frequently, this happens at the beginning of the rainy season when the contractor notifies the owner or storm water permit holder that someone should manage the storm water to prevent scheduling delays. Since this responsibility often is specifically excluded in bids, it can become a last-minute scramble to resolve. If not managed well, nearby businesses could be negatively impacted by dirt or mud in the streets, potentially resulting in complaints being filed with local inspectors.

While an early partnership offers owners the greatest value, it is still worthwhile for project managers who have experienced a violation to work with an experienced firm to quickly bring the site into compliance. With proper planning, storm water design challenges can be addressed, corrected with a licensed contractor, and monitored with weekly inspections. The associated costs can affect project budgets and profits if post-violation recommendations include operation of a chemical treatment system to manage the storm water.

In addition, understanding the permit requirements can be beneficial to help a contractor break the project into construction phases. This can help identify and minimize the area of disturbed soils that will come into contact with storm water and potentially require offsite discharge.

Dirt or mud in a public street can lead state inspectors to a project site.

Dirt or mud in a public street can lead state inspectors to a project site.

Ready to Respond

Ideally, planning for storm water management should be done before construction starts. A recent site in the Northwest received a permitting violation letter following an inspection citing a lack of storm water management at a project site. Although storm water inspectors only visit a fraction of ongoing construction sites, this site was flagged in the state’s permit system when the monthly discharge monitoring reports (DMRs) had not been submitted from the date of permit issuance. It is a common misconception among project managers that reporting is unnecessary if construction has not begun. Although variable in accordance with each state’s storm water regulations, in this case, the permit holder is required to submit a DMR by the 15th of each month after the date the permit was issued, whether or not construction has started, through the permit termination. Due to the lack of reported DMRs for this site, the state inspector visited the site to confirm the current status and if construction had begun, resulting in potential illicit discharges. The inspection violations and corrective actions required were discovered during this visit. Because Terracon’s consulting engineers on the project already were performing geotechnical services, they advised the client how to work with the inspector and quickly bring the site into compliance.

This project included demolition of a multi-level structure in order for the site to be redeveloped with a larger structure. The construction timing was mid-summer, when rainfall normally is minimal. However, the project had reportedly started earlier in the year with the demolition of the former building. At that time, it was reported that onsite catch basins were equipped with catch basin inlet protection during the demolition activities. Construction activities resumed at the site in the summer months and then existing surface coverings were removed, requiring additional best management practices (BMPs) to be properly installed and managed.

Violations noted by the state's storm water inspector included lack of BMPs; excess concrete on the ground not contained in a designated washout area; and cleaning or missing catch basin inlet protection. In this state, the permit for this location required weekly inspections completed by a state-certified erosion and sedimentation control lead (CESCL). Other administrative record keeping violations included failure to report DMRs from the permit start date, and failure to maintain storm water records and inspection sheets onsite to be available upon request.

Terracon worked closely with the agency and inspector to bring the site into compliance by implementing the necessary BMPs and maintaining all required records. In addition, the city inspector required a walk-through with the entire team and for the team to demonstrate how the site would be managing storm water during the upcoming rainy season.

Starting a project in the summer months can allow earthwork contractors to move quickly through daily tasks without spending significant resources for managing exposed soils and storm water BMPs. This is in part due to the allowable days a permit holder can leave soil unworked and exposed. While this is correlated to the geographic area of the project, the dry season can range from seven to 30 days and the wet season can range from two to 15 days. The beginning and end dates of these seasons also differ depending on a site’s location. All states and local jurisdictions can have different regulations, so it always is wise to plan and contact the appropriate agency.

Common Violations

At times, state inspectors are not directed to a job site by a direct complaint. Rather, “breadcrumbs,” such as dirt or mud in the street, may lead inspectors directly to a project site. These simple visual clues may cause an inspector to unexpectedly visit a project site. Frequently, the absence of properly installed and managed construction entrances are the root cause.

If a pile of crushed concrete from a recent onsite demolition will be reused for the construction entrance, it is important to be aware that recycled concrete will contribute to elevated pH in discharge samples. This common mistake could result in an inspector requiring complete removal of the installed construction entrance, an overlay with crushed rock, or other options. The state inspector will decide what is appropriate for a given site and situation. The CESCL will likely recommend the team follow permit guidelines and best practices.

Best Practices

The true test of a project’s Stormwater Pollution Prevention Plan (SWPPP) is the rainy season. Once storm water starts to accumulate and samples are being collected and tested, changes may be needed to both the SWPPP and site design. Knowing the site and the site's soils can help determine if a temporary sedimentation or infiltration storm water pond should be used. While this type of BMP may be proposed in SWPPPs to obtain a permit, it is not always the best option if it ultimately does not infiltrate at the site. If the turbidity cannot be managed by settlement over time, there may be a need for onsite water storage followed by chemical treatment. At construction sites where space is limited, it may not be possible to store storm water until turbidity is within acceptable standards for discharge. Therefore, chemical treatment may be necessary, requiring notification to the state agency to gain approval for the chemical treatment processes. Approval time is not always in line with the contractor’s schedule and can be frustrating.

Storm water permitting and management requirements vary widely among states, making it important for contractors to maintain good working relationships with individual state and local agencies. Understanding local storm water management requirements can help prevent significant potential fines and project delays. 

About the author

Eric A. Dubcak, CESCL, is project manager for Terracon Consultants Inc. Dubcak can be reached at [email protected] or 425.771.3304.