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Mixing engineering and biology

Mixing engineering and biology. Where Fish Passage is required.

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Mixing engineering and biology

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  1. Mixing engineering and biology

  2. Where Fish Passage is required Connectivity is required across the landscape wherever there are fish. Fish and fish habitat assessments standards are under development for TRANS. These are will indicate species specific and crossing specific information so sensitive sites (such as spawning sites) can be avoided when planning the location of watercourse crossing sites.

  3. Even areas that don’t exactly look like spawning habitat ….

  4. …require fish passage.

  5. In terms of culverts, dependent on one’s viewpoint, a culvert providing fish passage is envisioned as either this:

  6. or this………..

  7. Fish Passage Criteria Culvert Diameter Culvert Slope Roughness Velocity In certain cases, type of fish species and invertebrate species

  8. In the past, TRANS had approached regulatory agencies in comparing velocities and depths in a stream to what was in the culvert. For example, we used to produce this type of table: Note: This has now been updated.

  9. Unfortunately, we didn’t realize that the relationship between hydrotechnical design parameters was not clear to folks that weren’t used to dealing with it. For example, how did flow relate to velocity?

  10. ???

  11. In order to create this basic understanding with everyone we’ve used a real life example to illustrate the process. In this we are using the new (draft) Fish Passage Design Discharge (FPDD).

  12. The project involves 12 watercourse crossings – 3 of which are fish bearing. The fish species that is present is Athabasca Rainbow Trout.

  13. Athabasca Rainbow Trout sampled along Highway 32

  14. This is fish habitat.

  15. So is this.

  16. This is one of the culvert crossings we will be replacing.

  17. We’ve approached the issue of fish passage by using a series of informational tools. It proves due diligence and we now have a record of the site.Here are some of the tools.

  18. We produced individual site analyses using satellite imagery.

  19. Topographic

  20. Basin Size

  21. Slope • Crossing 2

  22. Site 2 – Slope Summary Channel Slope At Crossing S~ 1.2% Upstream of Crossing S~ 2.9 to 6.2% Downstream of Crossing S~ 1.8% (entering receiving channel)

  23. In comparison Site 3 Topographic

  24. Basin

  25. Slope • Crossing 3

  26. Site 3 – Slope Summary Channel Slope At Crossing S~ 1.1% Upstream of Crossing S~ 3.2 to 8.0% Downstream of Crossing S~ 0.8% (entering receiving channel)

  27. Summary Table

  28. Definitions: Q - Discharge = the rate of flow of water. It is the volume of water passing through a cross section of a channel in a given period of time. This is not a constant value; it is constantly changing. It is expressed as cubic meters per second (CMS) A - Area = Cross sectional area of flow in the channel. V - Velocity = the mean velocity for the cross section, as determined by V=Q/A.

  29. Definitions: Y - depth of flow B – channel bed width h – hydraulic bank height T – top width S – channel slope n – roughness parameter

  30. Although implicit in this presentation TRANS embeds culverts to D/4 up to 1 meter

  31. Techniques we are using to enable fish passage in steeper creeks 1% and greater. • Substrate Holders

  32. In culverts located on higher gradient streams and those where culvert velocities at the FPDD exceed those in the natural channel, substrate holders can help to provide more low velocity zones.

  33. Substrate holders are small weirs installed in the culvert to retain substrate in the culvert. The substrate provides additional roughness to reduce velocities, with an added benefit of flow variation. This method is typically effective for long culverts where backwater effects are lost.

  34. Substrate holders are designed to hold an engineered streambed in the culvert while allowing for natural sediment transport processes to occur in the stream. for culverts ≤ 3 m in diameter, 200 mm high weirs should be used with Class 1M rock riprap, and for culverts > 3 m in diameter, 300 mm high weirs should be installed with Class1 rock riprap.

  35. The maximum spacing of the substrate holders is equivalent to the substrate holder height divided by the slope of the culvert. Currently the effect of these substrate holders is being researched. More information is available in the draft ‘Culverts and Fish Passage’.

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