Client: Maryland State Highway Administration
Grant Date: 2002-2004
Engineered filter device along
U.S. Route 1 under construction
The LID Center is working with the University of Maryland, College Park and the Hydrology and Hydraulics Division of the Maryland State Highway Administration (SHA) on the development of LID techniques for urban retrofits. SHA is faced with the challenge of providing water quality retrofits (e.g. reducing impervious impacts) on road improvement projects in highly urbanized watersheds. With the advent of regulations such as Total Maximum Daily Load (TMDL) or watershed trading in impaired watersheds, they must also be prepared to reduce pollutant loads. Another key issue is the cost of right-of-way in urban areas. Centralized controls such as ponds take up a tremendous amount of space and reduce the amount of funds for the construction and delivery of the projects. Unfortunately, many existing State regulations are not suitable for linear transportation projects.
The Center has been developing standards and specifications for linear projects for SHA over the last several years in conjunction with the University of Maryland and SHA staff. Our process has been to plan and design a series of pilot projects that include pre- and post-construction monitoring. The Center works with SHA staff and their on-call highway design consultants to develop the plans and specifications. The existing specifications are examined during this process to identify how they need to be modified for the specific LID practices. This includes an evaluation of the MDE stormwater design and construction standards, including pre-treatment. For example, the Center worked with SHA on developing new standards and specifications for bioretention that more accurately reflect the flow characteristics of the soil media, as well as improvements to the media itself that have made it more effective and sustainable.