In March 2015, Prince George’s County, MD, and Corvias entered into a “first of its kind” innovative 33-year community-based public private partnership (CBP3), the Clean Water Partnership (CWP). The partnership is the first and largest CBP3 addressing stormwater management with a portfolio of hundreds of unique sites and projects located throughout the County. 


Brier Mill Stream restoration
Corvias’ partnership approach aggregates projects and creates economies of scale through innovative engagement, planning, design, and execution.

The CPB3 includes county-wide planning, community engagement, green stormwater infrastructure implementation, and stream restoration to treat the runoff from nearly 6,000 acres. The CWP benefits from Corvias’ alternative delivery model that combines programmatic management and contractor development to solve its infrastructure needs. This approach allows for the majority of the program’s funds to be used to contract with small, local, and minority-owned businesses, enabling them to participate in projects by removing financial barriers that small businesses typically face. To date, 79% of all funds have been awarded to target-class businesses, comprising of small, local, and minority-owned entities. 

Corvias’ compensation is tied to the achievement of performance metrics related to the environmental, socioeconomic, and technical specifications. Metrics include reduction of phosphorous, nitrogen, and sediment, target-class business participation, local resident utilization, annual Mentor Protégé Program graduates, fixed price, and schedule guarantee.


In 2012, Prince George’s County faced regulatory non-compliance of the Clean Water Act and needed a cost-effective and immediate solution to treat and manage stormwater runoff . The three major contributors to the poor health of Prince George’s waterways (the Anacostia River, Potomac River, Patuxent River, Piscataway Creek, and the Chesapeake Bay) are nitrogen, phosphorus, and sediment. Green stormwater infrastructure provides a nature-based solution to remove the pollutants from stormwater. To date, Corvias has constructed green infrastructure that removes more than 55,700 lbs. of nitrogen, 7,700 lbs. of phosphorous, and 5 million lbs. of suspended solids annually.

To help ensure a significant community impact, Corvias created a Mentor Protégé Program that has provided training and resources to more than three dozen firms.


Construction teams work on pond restoration in Prince george's county
To help ensure a significant community impact, Corvias created a Mentor Protégé Program that has provided training and resources to more than three dozen firms with a focus on local WMBE.

When the CWP began, there was not an existing contractor base that could implement large-scale infrastructure programs. To address this gap and to help ensure a significant community impact, Corvias created a Mentor Protégé Program that has provided training and resources to more than three dozen firms with a focus on local, women and minority owned business entities (WMBE). To date, the program has completed its sixth cohort and has 45 graduating companies. Each of these firms has opportunities to work within the CWP with access to mentoring companies and partnering opportunities with other graduates.

One of the initial challenges identified by small businesses was the lengthy payment schedule when working with local government, which created a financial burden that restricted their growth potential. To solve this, Corvias created a working capital payment program where Corvias pays all subcontractors promptly, ahead of County reimbursement, which is critical for maximizing local participation and allowing small businesses to access larger projects they otherwise wouldn’t be able to.


To create another layer of positive community impact, the CWP engages with each neighborhood to understand their needs and wants. To date, there have been more than 100 community listening events. Some of the co-benefit opportunities that have been uncovered include creating outdoor classrooms on school and recreational properties, a Teaching and Treating program which has educated more than 300 students, beautification and expansion of green space, and enhancing the natural environment.

Program Details

  • First of its kind CBP3 and EPA-endorsed model for counties to achieve stormwater compliance.
  • Local economic development through more than 63% resident utilization and 79% of work subcontracted to local small and minority-owned businesses.
  • Accelerated project timelines, reduced costs, and surety of execution.
Duration 33 years, 2015-2048
Capital Raise $350 million
Financing Structure Clean Water State Revolving Fund
Program Size 4,500 total acres
Development Costs $350 million
Total Local Economic Impact $655 million
CWP Stormwater
CWP Stormwater
CWP Stormwater Acteon Group
CWP Stormwater
CWP Stormwater Kirila Earthworks construction
CWP Stormwater Kirila Earthworks
CWP Stormwater pond
CWP Brier Mill Bridge
CWP Retention Pond
CWP Storm drain
CWP Stormwater Grace Management