Chloride circulation in a lowland catchment and the formulation of transport by travel time distributions
Article first published online: 5 AUG 2013
©2013. American Geophysical Union. All Rights Reserved.
Water Resources Research
Volume 49, Issue 8, pages 4619–4632, August 2013
How to Cite
2013), Chloride circulation in a lowland catchment and the formulation of transport by travel time distributions, Water Resour. Res., 49, 4619–4632, doi:10.1002/wrcr.20309., , , , and (
- Issue published online: 23 SEP 2013
- Article first published online: 5 AUG 2013
- Accepted manuscript online: 17 MAY 2013 12:13AM EST
- Manuscript Accepted: 13 MAY 2013
- Manuscript Revised: 10 MAY 2013
- Manuscript Received: 20 JAN 2013
- SNF-FNS . Grant Numbers: 200021-124930/1 , 200021-135241
- travel time distributions
 Travel times are fundamental catchment descriptors that blend key information about storage, geochemistry, flow pathways and sources of water into a coherent mathematical framework. Here we analyze travel time distributions (TTDs) (and related attributes) estimated on the basis of the extensive hydrochemical information available for the Hupsel Brook lowland catchment in the Netherlands. The relevance of the work is perceived to lie in the general importance of characterizing nonstationary TTDs to capture catchment transport properties, here chloride flux concentrations at the basin outlet. The relative roles of evapotranspiration, water storage dynamics, hydrologic pathways and mass sources/sinks are discussed. Different hydrochemical models are tested and ranked, providing compelling examples of the improved process understanding achieved through coupled calibration of flow and transport processes. The ability of the model to reproduce measured flux concentrations is shown to lie mostly in the description of nonstationarities of TTDs at multiple time scales, including short-term fluctuations induced by soil moisture dynamics in the root zone and long-term seasonal dynamics. Our results prove reliable and suggest, for instance, that drastically reducing fertilization loads for one or more years would not result in significant permanent decreases in average solute concentrations in the Hupsel runoff because of the long memory shown by the system. Through comparison of field and theoretical evidence, our results highlight, unambiguously, the basic transport mechanisms operating in the catchment at hand, with a view to general applications.