Modified-Puls Routing in Chuquatonchee Creek.
Abstract
A given reach of the Chuquatonchee was schematicized by a simple prismatic geometry, with a rectangular main channel for in-bank flows, to receive the large flood flows. The unsteady flow generated by the test floods in the test channel were modeled by solution of the complete one-dimensional Saint-Venant equations. Water-surface profiles (and, hence, stored volumes), as well as outflow, were monitored during the course of the calculation. Time and distance steps in the numerical procedures were taken small enough that their size played no significant role in the resulting solutions. The modified-puls method with a storage-outflow based on steady-flow profiles is not suitable for this reach, primarily because of the great size of the depth gradient relative to other forces driving or retarding the flow, and because the depth gradient is strongly a function of the unsteadiness in a channel of small slope. Further, the effect of depth on storage is highly exaggerated by the broad flat floodplains of this reach. By the same token, S(O) is highly event dependent, so that no single function, even approximately valid for a wide range of peaks, exists. While doubt has been cast on the accuracy of the topographical data gathered for Chuquatonchee Creek, it was found that the errors stemming from application of Modified-Puls to events in reaches for which it is theoretically unsuitable, were of sufficient magnitude that they alone could explain the noted discrepancy.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1985
- Accession Number
- ADA154285
Entities
People
- T. Strelkoff