A12. Repeat Cross Sections

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1. Objectives[edit]

  • Accurately measure channel dimensions
  • Measure the level of morphological adjustment

2. Method summary[edit]

Cross section surveys carried out before the restoration work can be compared with surveys taken in exactly the same place, but which are repeated at predefined intervals (for example immediately post restoration, then 1 year after and three years after). The repeat cross sections will then show how much the channel has changed as a result of the restoration work.

3. Advantages[edit]

  • Temporal variation analysis. Comparison insight into dynamics of landscape/bed form.

4. Limitations[edit]

  • Location recording to ensure accuracy – can introduce surveyor bias if inaccurate.
  • Time intensive if covering large areas and wide rivers.

5. Recommendation for method application[edit]

  • Make sure the grid reference and location are accurately documented to ensure accurate repeat survey and accurate analysis/comparison

6. Costs[edit]

Labour time.

7. Data analysis[edit]

Use cross-section profile graphs to determine changes in the bed form.

8. References[edit]

Harrelson C. C., Rawlins, C. L., and Potyondy, J. P. (1994)
Stream channel reference sites: An illustrated guide to field technique. General Technical report RM-245, Fort Collins, CO: United States Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station, 61p. Downloadable for free at http://www.stream.fs.fed.us/publications/documentsStream.html