The guideline for this subject is scheduled to be published in summer 2002. It contains culvert design options (no-slope, hydraulic and stream simulation), design considerations for fish passage at road crossings (culvert siting, culvert barriers, new culverts, channel profile, log sills, plank controls, roughened channels, boulder controls, flood capacity, migration timing, high/low flow, species and size of fish, culvert hydraulics, streambed simulation, baffles, channel backwater, culvert elevation), and other considerations of design (channel headcut and regrade, maintenance, water quality, ecological connectivity, habitat loss, channel impacts, construction impacts, risk of culvert failure).

Guiding Principles for Water-Crossings:

1. Culverts result in permanent direct loss of instream and riparian habitat.
2. Installation and maintenance of water crossings that confine or constrict the channel or floodplain will break ecological connectivity, alter channel processes, and change adjacent channel character and shape by affecting the movement of debris, sediment, channel migration, flood waters, and aquatic and terrestrial organisms.
3. Water crossings may create an entry point for road runoff pollutants.
4. Fish Passage can be hindered or blocked at water crossings.
5. Water crossings increase the risk of damage to the downstream habitat due to water crossing failure.
6. Cumulative impacts and risks of water crossings can be avoided or minimized by consolidating water crossings, employing full-span bridges, by simulating a natural channel through culverts, or removing water crossings. Access solutions that do not require water crossings are preferred.

Works in Progress - These "works in progress" have been developed to show the progress being made with the Aquatic Habitat Guidelines program. Drafts of guidelines currently under development, as well as information pertaining to their development, are presented here. The "works in progress" documents posted on this site illustrate the thoughts of those individuals contributing to the program. The information provided is continually changing and being updated. The "works in progress" documents do not necessarily reflect current guidelines or the policies of state agencies. By entering the links below, you agree to use these documents as discussion drafts only.

• Fish Passage Design at Road Culverts
• Notes From Draft Guidelines Peer Review - (PDF Format) To help ensure that the guidelines drafted as part of the Aquatic Habitat Guidelines program are comprehensive and reflect best available scientific information, they are reviewed in workshops that bring together regional experts, users, and regulators to discuss and critique the documents. Input from the workshops, as well as written comments, are reviewed and considered for incorporation into revisions of the guidelines documents.