Investigation of dominant hydrological processes in a tropical catchment in a monsoonal climate via the downward approach

Abstract

Abstract. This study explores the dominant processes that may be responsible for the observed streamflow response in Seventeen Mile Creek, a tropical catchment located in a monsoonal climate in Northern Territory, Australia. The hydrology of this vast region of Australia is poorly understood due to the low level of information and gauging that are available. Any insights that can be gained from the few well gauged catchments that do exist can be valuable for predictions and water resource assessments in other poorly gauged or ungauged catchments in the region. To this end, the available rainfall and runoff data from Seventeen Mile Creek catchment are analyzed through the systematic and progressive development and testing of rainfall-runoff models of increasing complexity, by following the "downward" or "top-down" approach. This procedure resulted in a multiple bucket model (4 buckets in parallel). Modelling results suggest that the catchment's soils and the landscape in general have a high storage capacity, generating a significant fraction of delayed runoff, whereas saturation excess overland flow occurs only after heavy rainfall events. The sensitivity analyses carried out with the model with regard to soil depth and temporal rainfall variability revealed that total runoff from the catchment is more sensitive to rainfall variations than to soil depth variations, whereas the partitioning into individual components of runoff appears to be more influenced by soil depth variations. The catchment exhibits considerable inter-annual variability in runoff volumes and the greatest determinant of this variability turns out to be the seasonality of the climate, the timing of the wet season, and temporal patterns of the rainfall. The water balance is also affected by the underlying geology, nature of the soils and the landforms, and the type, density and dynamics of vegetation, although information pertaining to these is lacking.

Modeling discharge and sediment concentrations after landscape interventions in a humid monsoon climate: The Anjeni watershed in the highlands of Ethiopia

“…Moreover, the advantages of this model lie primarily in its generalizable structure (water-balance type), its landscape-specific considerations (saturation-excess), its simple-routing method with minimal parameters (Jakeman & Hornberger, 1993;Montanari, Sivapalan, & Montanari, 2006;Perrin, Michel, & Andréassian, 2001), its model efficiency on the daily time step (Tilahun, Guzman, et al, 2013a;Tilahun, Mukundan, et al, 2013b), and its basis in processes observed in Ethiopia versus empiricism from the United States or Europe (Burt & McDonnell, 2015). It therefore provides an effective governing equation approach on a catchment scale based on a reduced form, direct field measurements spanning a range of scales, and theoretical studies (Burt & McDonnell, 2015;Kirchner, 2006).…”

Preliminary evaluation of the runoff processes in a remote montane cloud forest basin using Mixing Model Analysis and Mean Transit Time

“…For inference of the hydrological processes, multiple techniques are used, such as hydrometric data (e.g. Kirkby, ; McDonell, ; Bonell, ; Montanari et al , ), isotopical tracers (e.g. Dincer et al , ; Niemi, ; Payne and Schroeter, ; Sklash and Farvolden, ; Maloszewski et al , ; Turner et al , ; Buttle, ; Mortatti et al , ), chemical tracers (e.g.…”

A three-component hydrograph separation based on geochemical tracers in a tropical mountainous headwater catchment in northern Thailand

“…Uhlenbrook and Hoeg, 2003), tropical studies agree on the importance of fast flow components (different terms, listed in Table 1). Despite this agreement, the dominant processes continue to be among the most difficult and least understood ones (Montanari et al, 2006). Table 1 also shows the lack of attention to areas that receive < 2000 mm annual rainfall and are characterized by bimodal rainfall distribution with a distinct dry season (rainfall ≤ 20 mm month −1 ).…”