Over one million simulations were conducted using the Hec-Ras4b (US Army Corps of Engineers, 2004) model to evaluate the sensitivity of model predictions to field data accuracy, density and estimation techniques and provide guidance towards balancing human resource allocation with model accuracy. Notable differences were identified in model accuracy if a project is concerned with river processes occurring within the limits of the bankfull channel versus floodplain regions. Increased cross section discretization, bankfull channel detail and main channel roughness were of greatest field survey and measurement importance when processes relevant to the bankfull channel are of concern (i.e. geomorphic processes or sediment transport). Conversely, where flood conditions are of highest consideration, estimates of floodplain roughness dominate the accuracy of the results of computed water surface elevations. Results for this case study also demonstrate that higher orders of total station field surveys provide little additional accuracy in final predicted water surface elevations, relative to proper estimates of in-channel and floodplain roughness. As long as drift in field surveys has been accounted for during or subsequent to total station surveys, survey techniques such as hangers can be readily employed with very little increase in final model prediction error, while improving field data acquisition efficiency.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OWTU.10012/4205 |
| Date | January 2008 |
| Creators | Kuta, Robert Matthew William |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation |
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