The Massachusetts Department of Transportation ‐ Highway Division (MassDOT) has jurisdiction over numerous roadway stream crossings. Existing bridges and culverts, as well as future structures, potentially affect aquatic and terrestrial wildlife movement along the Commonwealth’s streams and riparian corridors, which in turn potentially affects the viability of wildlife populations and ecological systems. MassDOT considers it important to design new and replacement stream crossings to accommodate fish and other wildlife passage and prevent adverse impacts to important ecological systems. Therefore, MassDOT has developed this guidance document to address wildlife passage issues at new and replacement bridges and culverts and to comply with regulatory standards for stream crossings.
In Massachusetts, state and federal regulations of stream crossings apply requirements based on the Massachusetts River and Stream Crossing Standards.1 Chapter 2 of this document discusses these Standards in detail, along with the regulatory context in which the standards are applied. The remainder of the document presents MassDOT guidance on addressing the regulations and Standards. MassDOT anticipates that project planners and designers will use this guidance in conjunction with other standard MassDOT technical references to evaluate, select, and design stream crossings for conveyance capacity, structural integrity, and wildlife habitat continuity.
This document focuses on fish and other wildlife passage at new and replacement bridges and culverts at freshwater streams. At tidal stream crossings, wildlife habitat continuity and fish passage considerations differ from freshwater, non‐tidal systems. Application of wildlife accommodation measures appropriate for freshwater systems may be ecologically unjustified for tidal systems. This document does not address tidal systems. As this document focuses on wildlife passage, it also does not specifically address other potential habitat impacts associated with placing structures in or over streams, such as permanent impacts on benthic resources, impacts resulting from shade, and stormwater management impacts. Project planners and designers should consult MassDOT environmental professionals and other MassDOT reference materials for direction about these issues.