Category: Stormwater Symposium
There is an increasing demand to implement Low Impact Development (LID) methods into roadway projects especially in the northwest of the USA. Green infrastructure is the LID solution in stormwater management to help maintain the natural hydrological condition of the site. Depending on the project funding source and location, local and federal agencies require green infrastructure facilities to be prioritized in stormwater management. Such engineered facilities are designed to provide treatment and detention as required and to reduce long term maintenance costs. However, there is always a challenge to find the right approach that fits both the project condition and regulations. Challenges include high groundwater level, limited right of way, shallow existing stormwater system, low infiltration rate and limited funding. This paper discusses/compares regulations and challenges for implementing LID techniques in 5 transportation projects in the state of Oregon. Furthermore, the study discusses green stormwater treatment and detention design methods, bioengineered slope protection techniques and how to minimize impacts of a new infrastructure on ecosystem. Selected projects include two Bus Rapid Transit (BRT) systems, two roadway widenings and one intersection construction. Stockholder on these multi-jurisdictional agency projects are the City of Portland, City of Gresham, City of Eugene, Oregon Department of Transportation (ODOT), Western Federal Lands Highway Division (WFLHD), Clean Water Services (CWS), Washington County, and Union Pacific Railroad.
Hamed Hakimelahi– Water Resources Engineer, WSP (former WSP | Parsons Brinckerhoff), Portland, Oregon