Premium
Field mapping and digital elevation modelling of submerged and unsubmerged hydraulic jump regions in a bedrock step–pool channel
Author(s) -
Vallé Brett L.,
Pasternack Gregory B.
Publication year - 2006
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.1293
Subject(s) - bedrock , digital elevation model , geology , elevation (ballistics) , hydraulic jump , classification of discontinuities , channel (broadcasting) , jump , geomorphology , hydrology (agriculture) , flow (mathematics) , remote sensing , geotechnical engineering , geometry , computer science , mathematical analysis , computer network , physics , mathematics , quantum mechanics
High‐resolution tacheometric field surveying was integrated with computer‐assisted drafting to visualize and contrast three‐dimensional bed and water surface digital elevation models (DEMs) for submerged and unsubmerged hydraulic jump regions in a bedrock step–pool channel. Measurements were conducted for two discharge conditions. Since previous applica‐tions of three‐dimensional field mapping and digital elevation modelling of stream channels have been limited to smoothly contiguous gravel‐bedded systems, surveying was optimized by topographic setting and scaled to localized bed and water surface discontinuities. Traces and visualizations of the jump regions indicated that dichotomous decimetre shifts in water surface topography occurred for both jump regions from lower to higher discharges. Systematic removal of the survey points and DEM differencing indicated that point densities of ten points per square metre, in conjunction with a survey structure targeting grade breaks of 0·3–0·5 m, were required to capture decimetre form variations of the natural jump regions. The DEMs highlight the importance of recognizing the relationship between transcritical flow structures and localized topographic heterogeneities in bedrock channels. Copyright © 2006 John Wiley & Sons, Ltd.