Engineering Professor at Colorado State to Evaluate Stormwater Management in Denver, Other Cities

Colorado State University’s Urban Water Center has been awarded a contract valued at $800,000 from the Water Environment Research Foundation in a first-of-its-kind study to develop planning tools for municipalities to determine the best way to protect urban waterways from pollution due to stormwater runoff.

Municipal stormwater management agencies in Denver, Los Angeles, Seattle and Philadelphia have volunteered to participate in the study, which is intended to provide municipalities with effective tools for improving stormwater drainage. Stormwater can carry harmful pollutants such as automobile products or chemicals such as antibiotics used for humans and animals into streams.

The study will examine whether best management practices for stormwater pollutant control are directly linked to improved water quality in streams, said Larry Roesner, professor in the Department of Civil and Environmental Engineering and director of the Urban Water Center.

"This study will provide the foundation for making better, fact-based decisions on the types of Best Management Practices that local governments use and approve within their jurisdictions," said Ben Urbonas, manager, Master Planning Program for the Urban Drainage and Flood Control District. The district covers 1,608 square miles and includes Denver, parts of the six surrounding counties and all or parts of 33 incorporated cities and towns.

"The issue at hand is selecting the Best Management Practices that are most effective in protecting the receiving waters of the state of Colorado and are also most cost effective when full life-cycle costs are considered," Urbonas said. "That includes not only initial cost but also the cost of maintenance, eventual rehabilitation and administering the oversight required by the state of cities and counties to ensure that facilities in the ground continue to function for years to come."

Commonly used methods for treating runoff include settling and biofiltration that remove solids and associated pollutants from the runoff. Wetlands and created ponds are also used to remove pollutants plus nutrients that stimulate algae growth in urban waterways.

Colorado State engineers are leaders in the design of pragmatic computerized models that can help cities predict their success with these runoff-control measures. The university plans to hire subcontractors, including CDM, CH2MHill and Geosyntec, to provide specialized expertise on the study.

"We’re developing tools municipalities can use to make better decisions about management practices and where they need to put them so they can effectively predict impacts on water quality in streams, lakes and other natural water areas," said Christine Rohrer, a research associate who is working on the grant with Roesner and Assistant Professor Brian Bledsoe.

"Some metropolitan stormwater agencies have experience with state-of-the-art controls that are used to meet water-quality standards," Roesner said. "Denver and Philadelphia, in particular, are leaders in this area. However, they and most other American municipalities lack the planning tools to determine which controls work best in a given situation, how many are required in a river basin, and what is the whole-life cost to the agency for implementing these controls."

Roughly half the streams in the country remain polluted as a result of storm runoff. Continuously flowing streams such as Spring and Fossil creeks in the Fort Collins area are examples of the numerous small streams that must meet minimum federal water quality standards., Rohrer said.

"It’s our responsibility to take care of the environment," said Rohrer, who is obtaining her doctorate in civil and environmental engineering. "I’m glad in my job I can do that."

Roesner holds the first endowed chair in the Department of Civil Engineering known as the Harold H. Short endowed chair for urban water infrastructure systems. He was elected to the National Academy of Engineering in 1990 and is a nationally recognized expert in the development and application of hydrologic, hydraulic and water quality simulation models. He served as chief technical officer and senior vice president at Camp Dresser and McKee Inc. before coming to Colorado State in 1999. Roesner’s area of specialization since 1970 has been urban hydrology and nonpoint source pollution control.