BACKGROUND

NCHRP Project 20-68A, Scan 16-02, “Leading Landscape Design Practices for Cost-Effective Roadside Water Management,” was conducted to investigate how transportation agencies are applying principles and practices of green infrastructure (GI) for roadside water management to mitigate adverse impacts of flooding, drought, and temperature extremes affecting their infrastructure.

Although there is a lot of information available from environmental and national highway agencies, only a few state departments of transportation (DOTs) seem to be fully implementing GI practices and recommendations. One reason for this is the lack of a common definition for GI, which was highlighted in a 2022 article titled What is green infrastructure? A study of definitions in US city planning. This lack of standardization can make it difficult to compare approaches and best practices. In 2019, the Water Infrastructure Improvement Act provided a definition of GI that encompasses a range of measures to store, infiltrate, or evapotranspirate stormwater using plant or soil systems, permeable surfaces, and stormwater harvesting. However, other organizations use different definitions, further contributing to the lack of consistency in GI implementation.

The scan team report for NCHRP Project 20-68A, Scan 16-02, identified eight categories of recommendations based on their findings. Information development and sharing is crucial for successful GI implementation, but there is currently no national effort to create a community of practice or collaborate among the related topical committees at the Transportation Research Board (TRB) and at the American Association of State Highway and Transportation Officials (AASHTO). Moreover, there are no peer exchanges or conferences held specifically for GI implementation by state DOTs. To address this, a series of national-level workshops will be conducted to share the scan team's findings and provide a platform for participants to discuss and plan the creation of a community of practice.

OBJECTIVE 

The objective of this project is to implement the benefits of GI for effective roadside water management. This objective will be realized by (1) the development of contextual definitions of GI; (2) the development and conduct of workshops to disseminate information and gather additional information on GI; and (3) the development of viable approaches for funding and continuation of information exchange on GI practices.