Inside Maryland's mission to tackle stormwater

Inside Maryland's mission to tackle stormwater

The state of Maryland tackles stormwater mitigation through a first-of-its-kind partnership between conservation groups and the private sector.

September 29, 2020

Since becoming an independent company in 2014, OptiRTC Inc., Boston, has grown to become a leader in stormwater infrastructure control systems. Operating in 21 states and over 160 sites around the country, the company provides cloud-based solutions to connect, manage and operate stormwater systems at a watershed scale.

Most recently, Opti has made headlines for a new public-private partnership to benefit the Chesapeake Bay watershed through advanced stormwater control technology. In November 2019, a joint venture between the U.S. Environmental Protection Agency (EPA) Region IIIWalmartThe Nature Conservancy (TNC) and Opti Development Partners LLC was announced to help reduce pollutants and curb local flooding in Maryland.

“In most of the country, you need private landowners to participate,” says David Rubinstein, CEO of Opti. “So, we pulled together a relationship with the Nature Conservancy and Walmart to be able to bring these kinds of assets—primarily stormwater ponds and retention basins—to the state and say, ‘We have an opportunity to engage with the private sector, and to have it financed in a manner where you can save a lot of money stretching and leveraging your taxpayer dollars and doing good things for your community.’”

According to the Stormwater Report, a news service operated by the Water Environment Federation, typical stormwater retention ponds accept large volumes of water during heavy storms and drain it at a controlled pace that discourages local flooding and nourishes groundwater aquifers.

However, achieving the most benefit from retention ponds requires operators to know when and how much precipitation is expected, the correct drainage rates to prevent both flooding and pond overflow, and how to put this information to work quickly during potentially extreme and sudden downpours.


Opti’s solution, known as a “smart pond,” takes the guesswork out of retention pond operations by outfitting stormwater ponds with sensors to monitor water levels and remaining storage volumes.

“[With the smart pond], we’re actually able to retain the water at a higher level because it’s not passive outflow anymore, it’s an automated valve,” says Rubinstein. “What we can do is drain the water out before the next storm comes in. So, not only is it handling water quality, but it handles flood mitigation.”

The internet-enabled system also receives up-to-the-minute weather forecasts. When expecting rain, the system can automatically open valves at the bottom of the pond to minimize flood risks while maximizing retention time. Longer retention times increase water quality by enabling the pond to capture more sediment and nutrients before draining the runoff, the Stormwater Report says.

“[This] technology can have multiple purposes, and having that real-time data can actually inform us as to what the issues are,” says Rubinstein. “For instance, we might sense that the water level is going down, but the valve is not open. Well, there could be a leak in the liner if [the valve] is blocked, etc. There’re a whole host of things that we’re able to diagnose.”

Operators also can manually tune the system from any smartphone, computer or other internet-capable device. The smart pond’s monitoring data is hosted in a software application called Opti Platform, which connects the distributed stormwater systems to a single, secure cloud management layer.


The Chesapeake Bay project represents a first-of-its-kind partnership between the Maryland state government, conservation groups and the private sector.

As part of an agreement with Maryland Environmental Services (MES), the Maryland Department of Transportation (MDOT) will contribute $4 million to facilitate the installation of smart pond technology at a pilot-sized group of retention ponds.

According to EPA, there are currently 65,000 privately held stormwater management ponds in the Chesapeake Bay watershed alone, including 18,500 in Maryland. To demonstrate the potential of working with the private sector to improve stormwater management, the Maryland Department of the Environment (MDE) and MES approached Walmart with the idea to install smart pond technology in retention ponds near four Walmart parking lots in Maryland.

“This is an exciting opportunity to demonstrate how private-public partnerships can be used to advance long-term environmental preservation goals, and in particular, to help protect the Chesapeake Bay,” said Roy McGrath, director and CEO of MES, in a release. “MES is excited to put its organizational skill and expertise in service of this groundbreaking project.”

"[With the smart pond], we’re actually able to retain the water at a higher level because it’s not passive outflow anymore, it’s an automated valve.” –David Rubinstein, CEO of Opti

The contract between MES and TNC/Opti was finalized on July 8, 2019, with the technology expected to be installed at the four Walmart ponds between summer and fall of this year.

“This program reflects MDOT’s commitment to be responsible stewards of the environment and our mission to explore partnerships and innovation to make our communities better,” MDOT Secretary Pete Rahn said during a press conference at the Walmart Superstore in Fruitland, Maryland—one of the sites that will receive the smart pond technology.

The MDOT public-private partnership also complements other initiatives geared towards implementing water quality improvement strategies that meet the EPA’s Chesapeake Bay total maximum daily load (TMDL) requirements for the year 2025.


The cost to MDOT for the new credits is about $37,500 per acre, including installation of smart pond technology and 20 years of monitoring, inspecting, operating and pond maintenance conducted by TNC/Opti. That cost is significantly less than the average construction cost of $150,000 per impervious acre treated through stormwater devices such as swales, bioretention cells and stormwater ponds, Opti says.

“We took their cost of a water quality credit down from $150,000 to approximately $40,000. So, the economics become very attractive,” says Rubinstein.

MDOT’s payment of $4 million will purchase 100 acres worth of Chesapeake Bay impervious area treatment credits generated by the smart ponds at Walmart and additional locations that are still being finalized.

The credits will help MDOT State Highway Administration (SHA) satisfy compliance goals set by the MDE to treat stormwater runoff from 4,621 acres of impervious area by October. As of July 1, 2019, MDOT SHA had treated 3,472 acres, or 75 percent of that requirement.

The smart pond partnership represents the first time a state department of transportation is purchasing credits from a water quality trading program. MDE established Maryland’s program, creating a water quality marketplace for credits generated by pollutant reductions elsewhere in Maryland’s portion of the Chesapeake Bay watershed. This market-based approach offers economic incentives for pollutant reductions.

“We need innovative new ideas and partnerships to address stormwater pollution—the fastest growing source of freshwater pollution worldwide,” said Mark Bryer, director of the TNC’s Chesapeake Bay Program, in a release. “This project is a perfect example of what the Chesapeake Bay needs: public and private sectors working together to harness technologies that deliver low-cost solutions to water pollution that can be replicated across the Bay watershed and beyond.”

This article originally appeared in the July/August issue of Waste Today. The author is the assistant editor of Waste Today and can be reached at