Quantifying hydrological budgets and pathways in a small upland catchment using a combined modelling and tracer approach

Abstract

Abstract:Hydrological budgets and flow pathways have been quantified for a small upland catchment (1.76 km 2 ) in the northeast of Scotland. Water balance calculations for four subcatchments identified spatial variability within the catchment, with an estimated runoff enhancement of up to 25% for the upper western area, compared with the rest of the catchment. Data from spatial hydrochemical sampling, over a range of flow conditions, were used to identify the principal hillslope runoff mechanisms within the catchment. A hydrochemical mixing analysis revealed that runoff emerging from springs in various locations of the hillslope accounted for a significant proportion of flow in the streams, even during storm events. A hydrological model of the catchment was calibrated using the calculated stream flows for four locations, together with results from the mixing analysis for different time points. The calibrated model was used to predict the temporal variability in contributions to stream flow from the hillslope springs and soil water flows. The overall split ranged from 57% : 43% spring water : soil water in the upper eastern subcatchment, to 76% : 24% in the upper western subcatchment.

On the value of combined event runoff and tracer analysis to improve understanding of catchment functioning in a data-scarce semi-arid area

“…Christophersen et al, 1990;Uhlenbrook et al, 2002;Dunn et al, 2006;Laudon et al, 2007;Hrachowitz et al, 2009), analysis of catchment transit time distributions (e.g. McGuire et al, 2005;Hrachowitz et al, 2010a;Lyon et al, 2010) as well as interpretations of the spatio-temporal evolution of tracer concentrations in soils and streams (e.g.…”

Dissolved organic carbon dynamics in a UK podzolic moorland catchment: linking storm hydrochemistry, flow path analysis and sorption experiments

“…1), part of the Glensaugh UK Environmental Change Network (ECN) site (http://www.ecn.ac.uk/sites/glens). The Cairn Burn catchment (NE Scotland) has been the focus of a number of investigations into hydrological flowpaths (Dunn et al, 2006) and DOC properties in soil solutions (Lumsdon et al, 2005;Stutter et al, 2007a). Average annual precipitation is 1115 mm at 300 m altitude (2004)(2005)(2006).…”

“…Transport processes include DOC sources within different landscape units (McGlynn and McDonnell, 2003;Jensco and McGlynn, 2010) and the connectivity of these units with changing hydrology (Dunn et al, 2006;Laudon et al, 2011). Biogeochemical processes include a range of geochemical (sorption and alteration of DOC by contact with soil surfaces) as well as biological (for example, microbial processing and plant exudation) interactions.…”

Untangling hydrological pathways and nitrate sources by chemical appraisal in a stream network of a reservoir catchment

“…Stream waters (8.78 ‰) were enriched in heavy isotopes as a consequence of evaporation with respect to shallow groundwater (from −3.42 ‰ to 2.16 ‰). It is known that during low-flow periods in semiarid areas evaporation generates characteristically heavy isotope enrichment in residual surface waters above +3 ‰ (Gonfiantini, 1986). The difference in stable isotope composition between the shallow groundwater and the stream water can be used for tracing the contributions of water to the streams.…”

“…Many studies have been carried out regarding the role of instream processes as decisive factors of stream water chemistry. Such processes can be strongly related to hydrological conditions such as connectivity among streams, temperature regime, rainfall occurrence and intense evaporation (Dunn et al, 2006;Y. Liu et al, 2008;Meredith et al, 2009).…”