The Latest on Stream Crossing

Originally Printed in the Maine Aggregate Association’s Newsletter — Sand & Gravel News

by Steve Blais, PE

Crossing a stream with a road or driveway requires a permit from the Department of Environmental Protection (DEP) under the Natural Resources Protection Act (NRPA). A permit by rule (PBR) under DEP Chapter 305 allows for approval of an NRPA permit in two weeks provided all application submission are provided and standards are met.

Legislation enacted earlier this year (P.L. 2009 Chapter 460) required that the DEP modify Section 10 of Chapter 305 Permit by Rule Standards (PBR) to require municipalities to achieve natural steam flow when repairing or maintaining stream crossings. Natural stream flow improves stream hydraulics and habitat connectivity. It also allows for the passage of fish and other aquatic organisms.

Crossing structures that span 1.2 times the bankfull width of a stream are presumed to allow for natural stream flow.

The rule amendments were to apply to “water courses containing fish”. The DEP has modified Chapter 305 accordingly and has made the new rules applicable to everyone not exempt under P.L. Chapter 460, and not just municipalities. Furthermore, discussions with fisheries biologist revealed that fish may occupy some portion of any stream. Accordingly, the new rule defines “watercourse containing fish” to mean the same as “river, stream, or brook”. Bottom line: the new rule applies to all rivers, streams, and brooks.

Changes in Design Requirements:

Stream measurements are now based on bankfull capacity of the streams and no longer on the normal high waterline. Definition of Bankfull Width: The width of the bankfull channel at the point the water level, or stream state, begins to overflow into an active floodplain or bench. Where only one side of a stream contains a floodplain or bench, the width is measured as a straight line from that point horizontally across the stream to the opposite bank. Where no floodplain or bench exists, the width is measured as a straight line between the highest points of the normal high water line on each bank.

Span or diameter of crossing structures need to be 1.2 times the stream bankfull width. As an example, a 5-foot wide (bankfull) stream would require a 6-foot wide culvert. A good portion of this culvert would need to be buried to achieve the required span. Proposed structures are also required to have a cross sectional area for 3.5 times the stream cross sectional area, an increase of 0.5 from the old rule.

If ledge prevents properly embedding the culvert, an open span structure must be used.

An exception to this rule is if the ledge creates a barrier for fish passage. Sign-off from the IF&W and Department of Marine Resources (DMR) is required to determine if the ledge is a barrier for fish passage. Open bottom structures are also required in perennial watercourses that slope more than 2% or are considered navigable watercourses. The old rule allowed pipe arches in this case.

Culverts must be corrugations or similar internal roughness to decrease water velocity and stream diversions are now required during construction for all streams. The old rule required diversions for streams 3 feet deep or less.

Waivers and Exemptions:

Maintenance, repair or replacement of smooth-bore culverts and culverts that are being changed to smaller diameters are not exempt. Certain maintenance and repair activities at existing crossings that result in a smaller diameter culvert, such as so-called slip-lining, or that use smooth bore culverts may be allowed
in certain cases to waiver from the new standards.

Many sections of the rule do not apply to forest management activities.

Submission requirements:

New submission requirements include scaled drawings showing the cross sectional area of the stream and the size and type of crossing structure to be used. These drawings must show the bankfull width and calculations to support the cross-sectional area of the stream as well as the available cross-sectional area of the proposed structure. Further requirements were added with respect to Site photographs. These photographs must be taken immediately upstream and downstream of the crossing. Applicants will need to submit approval from the Departments of Inland Fisheries (IF&W) and Wildlife and Marine Resources (DMR) for the following:

  • Crossing constructed between October 2 and July 14 of the year.
  • Culvert maintenance, repair or replacement activities that use smooth bore culvert or result in a smaller diameter culvert than the culvert being maintained, repaired or replaced.
  • Crossings that will not allow for fish passage where the purpose is to prevent the spread of invasive fish species, such as pike.
  • Any crossing where existing ledge prevents embedding of the crossing structure and the ledge condition is deemed a barrier to fish passage by IF&W and DMR.

Cost:

DEP states that, based on 350 some recent stream crossings, new crossing may require a culvert two sizes bigger to meet the new standards, which could cost $100 to $300 more. It does not appear that these numbers include additional earthwork, and the use of larger installation equipment. The biggest cost implications will be for projects requiring an open bottom structure. These structures can be as much as 10 times more costly to install.

These rules will be presented to the Board of Environmental Protection and once adopted will be in effect for 2010.