Determining surface and hyporheic retention in the Yarqon River, Israel
2010 (English)In: / [ed] Dittrich, Koll, Aberle & Geisenhainer, Braunschweig, Germany: Bundesanstalt für Wasserbau , 2010, 1767-1774 p.Conference paper (Refereed)
Solute transport in rivers is controlled by surface hydrodynamics and by mass exchanges with distinct retention zones. The downstream propagation of transported substances such as nutrients and contaminants is affected by the transient storage in surface dead zones (e.g., eddies, vegetated pockets) and in the permeable subsurface in the so called hyporheic zones. General residence time models allow to represent surface and hyporheic retention processes via specific modelling closures, yet current stream tracer tests do not allow a clear separation of the different storage components. A conceptual distinction can be given by associating in-channel transient storage to relatively short time scales and hyporheic retention to longer time scales. Based on this conceptual separation, we apply the STIR (Solute Transport In Rivers) model to interpret tracer test data from four different reaches of the Yarqon river, in Israel. In the model we use an exponential residence time distribution (RTD) to represent surface storage processes and we experiment with two distinct modelling closures to simulate hyporheic retention: an exponential RTD and a distribution approximating Elliott and Brooks’ (1997) solution for bedform-induced hyporheic exchange which is asymptotically a power law. Both modelling closures lead to acceptable approximations of the observed breakthrough curves, but better fits are obtained using an exponential distribution to represent hyporheic (long timescale) retention. We then compare the results in terms of retained mass. The comparison shows that, although the two modelling choices lead to differences in the calculated retained mass, the model response in terms of relative importance of surface and hyporheic retention in the four reaches examined remains unaltered.
Place, publisher, year, edition, pages
Braunschweig, Germany: Bundesanstalt für Wasserbau , 2010. 1767-1774 p.
STIR, Transient Storage, Hyporheic Layer, Dead Zones, Vegetated Zones
Ocean and River Engineering
IdentifiersURN: urn:nbn:se:kth:diva-81632ISBN: 978-3-939230-00-7OAI: oai:DiVA.org:kth-81632DiVA: diva2:497700
River Flow 2010, International Conference on Fluvial Hydraulics
QC 201202132012-02-132012-02-102012-02-13Bibliographically approved