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Protecting our Most Precious Natural Resource

Stormwater Compliance

Northstar is dedicated to ensuring our clients stay in compliance with all regulatory authorities pertaining to stormwater management and SCM maintenance.  We are certified to perform routine maintenance, repairs, installation and inspections on a vast majority of stormwater control measures currently in use today. (Learn more to see types of SCMs)

Stormwater Services


Northstar employs a team of highly skilled personnel ready to assist with any phase of your remediation project. Our experienced professionals have successfully completed remediation of impacted soil and groundwater in a variety of site conditions.

We evaluate risks and impacts and provide our clients with remediation plans tailored to site specific regulatory compliance requirements, closure and end-goal targets, proposed property uses and cost efficiency. We work with each site to minimize interruptions to key facilities during the remediation process while completing the project within a reasonable time frame.

Bio-Retention Basins

Bioretention basins are landscaped depressions or shallow basins used to slow and treat on-site stormwater runoff. Stormwater is directed to the basin and then percolates through layers of filter media where it is treated by a number of physical, chemical and biological processes. The slowed, cleaned water is allowed to infiltrate native soils and/or directed to nearby stormwater drains or receiving waters.

All bioretention systems require maintenance in order to function correctly and remove pollutants from the stormwater runoff. Typical maintenance includes invasive weed and vegetation removal, erosion control and monitoring, sediment removal, mulch monitoring and replacement, plant management, infiltration monitoring, inlet and outlet structure inspections, and trash/debris removal. Routine maintenance is generally a much cheaper route than repairing a failed bioretention system.

Pervious Pavement

Pervious pavement is a permeable pavement surface with an underlying stone reservoir to temporarily store surface runoff before it infiltrates into the subsoil; this porous pavement replaces traditional pavement allowing stormwater runoff to infiltrate directly into parking lots to receive treatment. The benefit of porous pavement is it allows retrofitting of existing paved surfaces instead of taking up a large space installing ponds or bio-retentions.

Regular maintenance is extremely critical for porous pavement to continue functioning properly; the frequency of maintenance depends on the quality of the design, but porous pavement will clog if left unattended. It should be vacuum swept regularly and cleaned of debris and sediments monthly. Occasionally the porous pavement should be serviced by professionals using a pressure hose and vacuum truck to both dislodge and collect sediments that get trapped in the pores of the pavement.

Underground Water Quality Units (Proprietary Devices)

Water quality units come in a variety of shapes and sizes with one main purpose, to remove pollutants from stormwater runoff before conveying the water downstream. These systems can be as simple as an underground vault that slows the flow of water, allowing sediments to drop out and remain in the unit. They can also be more complex, containing filters that are designed to aggressively remove oil and sediment from the runoff as it flows through the unit.

As with other stormwater control measures, maintenance is critical to keep the water quality unit functioning as designed. Maintenance frequency varies depending on the type of unit as well as the amount of stormwater runoff produced by the site.

Constructed Wetlands

A constructed wetland is an artificial wetland created to duplicate the processes occurring in natural wetlands. In these systems, water, plants, microorganisms, soil, the sun and the air all interact to improve the quality of the water that enters the system. When properly constructed and maintained, constructed wetlands can effectively remove many pollutants from municipal and industrial wastewater and stormwater. These pollutants include, but are not limited to, suspended solids, nitrogen, phosphorous and even heavy metals. Although constructed wetlands are extremely functional, they can also be aesthetically pleasing and provide a habitat for various animals, creating a public attraction for visitors to your property.

Once established constructed wetlands tend to be relatively low-maintenance landscapes, but benefit greatly from a management plan which aims at maximizing ecological function and aesthetics. There are eight general wetland types: fen, bog, seepage slope, seepage bog, mars, wet prairie, swamp, and bottomland forest; each of these require slightly different considerations however there is general maintenance that is applicable to all of them. General maintenance involves the consideration of the following factors: vegetation/wildlife management, water depth control structures, cleaning and maintaining inlet/outlet structures, inspecting embankments and structures for damage, inspecting monitoring devices, depth of sediment accumulation before removal is required, the acceptable range of water depth fluctuation, and supplemental water sources entering the wetland.

Detention (Dry) Ponds

Dry ponds are typically dry basins, with a concrete inlet and outlet structure, that attempt to replicate naturally vegetated areas by detaining excess stormwater during rain events and allows sediment and pollutants to settle out of the stormwater as it gradually drains out of the pond. Dry ponds are particularly effective at flood control and preventing channel erosion by reducing peak flow during storm events and giving the water a place to be stored safely.

Maintenance of these systems is crucial for proper functionality; as these systems build up sediment, as they are designed to do, the amount of stormwater that can be detained is decreased over time, and orifices leading to and from the pond can be obstructed. Maintenance typically involves simple weed control, debris removal, and inspection of the structures that constitutes the dry pond, but occasionally sediment needs to be removed from the pond in order to restore the pond’s full stormwater storage capacity.

Retention (Wet) Ponds

Wet ponds are among the most cost-effective and widely used stormwater treatment practices; they are constructed basins that have a permanent pool of water and sometimes landscaped plants around their perimeter. As stormwater enters the pond, the velocity is greatly decreased, allowing suspended particles to settle out of the runoff; simultaneously, the ‘treated’ water from the previous storm exits the system as the new stormwater enters. Nutrient uptake via biological activity in the pond is also an effective mechanism for stormwater treatment.

Wet ponds are very durable and require less maintenance than other applicable water quality controls. However, they do require regular maintenance for optimal operation as designed. Maintenance on these ponds typically includes mowing, removal of dead vegetation/debris regularly, repairing eroded or undercut areas as needed, and monitoring sediment accumulations in the main pond area so it can be removed before the pond becomes eutrophic and completely ineffective.

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