Adjacent catchments with similar patterns of land use and climate have markedly different dissolved organic carbon concentration and runoff dynamics

Abstract

Temporal patterns in specific runoff, dissolved organic carbon concentrations [DOC] and fluxes were examined during two periods: 1994–1997 (period 1) and 2007–2009 (period 2) in five adjacent tributary catchments of Lake Simcoe, the largest lake in southern Ontario, Canada. The catchments displayed similar patterns of land use change with increases in urbanization (5–16%) and forest cover (0.2–4%) and declines in agriculture (4–8%) between 1994 and 2008. Climate in the catchments was similar; temperature increased slightly, but no significant change in precipitation was observed. Despite similar pattern of climate and land use, runoff responses and tributary [DOC] were different across the catchments. Following a very dry year (i.e. 1999), runoff increased steadily until the end of record. We observed increased variability in tributary [DOC] and higher DOC exports in period 2. This led to ~10% increase in [DOC] and a 13% increase in flux between the two study periods. Between the two periods, [DOC] increased by 15% in spring and 25% in summer, whereas flux increased by 17% in spring and 48% in summer. [DOC] was consistently higher in the growing (summer + autumn) than the dormant (winter + spring, minus spring melt months) seasons, but no unique pattern or simple linear flow/concentrations relationships existed. This suggests complex spatial and temporal pattern to runoff controls on DOC and flow dynamics in adjacent catchments. We therefore caution against extrapolating from monitored to unmonitored catchments. Copyright © 2012 John Wiley & Sons, Ltd.

Hydrological footprints of urban developments in the Lake Simcoe watershed, Canada: a combined paired‐catchment and change detection modelling approach

“…Previous remote sensing analysis, as presented in Oni et al . (), showed that land use change was evident across the LSW. The results showed that impervious surfaces increased by 5–16% because of urbanization, forest slightly increased by 4%, while agriculture declined by 4–8% across the LSW.…”

“…Previous research in the LSW (Oni et al ., ) showed significant site‐by‐period interactions for run‐off across the watershed. Landscape development such as urbanization could amplify catchment run‐off flashiness during spring melt regimes (Cheng and Wang, ) and enhance overland flow that results in greater run‐off peaks (Rose and Peters, ).…”

“…Ide et al ., ; Schelker et al ., ) rather than urban catchments. This is because, in part, of the unavailability of undisturbed reference catchments in close proximity to the urban catchment of interest (Oni et al ., ).…”

PERSiST: a flexible rainfall-runoff modelling toolkit for use with the INCA family of models

“…While there is a great deal of research interest in Prediction in Ungauged Basins (PUB; Hrachowitz et al, 2013a, and references therein), PERSiST has been designed for use in flow simulations at gauged catchments. Thus, regionalization studies such as Hellebrand et al (2011) have very different modelling goals than those motivating the development of PERSiST, which may be more useful for understanding the differences in hydrological response between apparently similar catchments such as those reported by Oni et al (2013).…”

Long-term patterns in dissolved organic carbon, major elements and trace metals in boreal headwater catchments: trends, mechanisms and heterogeneity

“…This has been described as "Aqua Incognita" by Bishop et al (2008). Large river basins will contain a mixture of DOC of different quality from various landscape sources making the DOC dynamics more uniform over time and space (Oni et al, 2013). In contrast, the DOC processes in headwaters are dependent on both local soil conditions and hydrology that both have a heterogeneous nature.…”