Paper No. 96048 of the Journal of the American Water Resources Association (formerly Water Resources Bulletin). Discussions are open until December 1, 1997.
PRECISION OF CHANNEL WIDTH AND POOL AREA MEASUREMENTS1
Version of Record online: 8 JUN 2007
JAWRA Journal of the American Water Resources Association
Volume 33, Issue 3, pages 647–659, June 1997
How to Cite
Myers, T. J. and Swanson, S. (1997), PRECISION OF CHANNEL WIDTH AND POOL AREA MEASUREMENTS. JAWRA Journal of the American Water Resources Association, 33: 647–659. doi: 10.1111/j.1752-1688.1997.tb03539.x
- Issue online: 8 JUN 2007
- Version of Record online: 8 JUN 2007
- stream morphology;
- aquatic habitat;
- stream surveys;
- survey design
ABSTRACT: The precision of width and pool area measurements has rarely been considered in relation to downstream or at section hydraulic geometry, fisheries studies, long-term or along a continuum research studies, or agency monitoring techniques. We assessed this precision and related it to other stream morphologic characteristics. Confidence limits (95 percent) around mean estimates with four transects (cross-sections perpendicular to the channel center-line) ranged from ± 0.4 to 1.8 m on streams with a width of only 2.2 m. To avoid autocorrelation, transects should be spaced about three channel widths apart. To avoid stochastic inhomogeneity, reach length should be about 30 channel widths or ten transects to optimize sampling efficiency. Precision of width measurements decreased with decreased depth and increased with stream size. Both observations reflect variability caused by features such as boulders or coarse woody debris. Pool area precision increased with pool area reflecting increased precision for flat, wide streams with regular pool-rime sequences. The least precision occurred on small, steep streams with random, boulder or coarse woody debris formed pools.