Streamflow regime of a lake-stream system based on long-term data from a high-density hydrometric network |
| |
| Authors: | Danielle T Hudson Jason A Leach Kara Webster Daniel Houle |
| |
| Institution: | 1. Natural Resources Canada, Canadian Forest Service, Great Lakes Forestry Centre, Sault Ste. Marie, Canada;2. Science and Technology Branch, Environment Canada and Climate Change, Montréal, Canada |
| |
| Abstract: | Northern landscapes are dominated by a mosaic of lakes and streams, yet only a limited number of studies have explored how these lake-stream networks influence streamflow regimes. In order to gain further insight into the hydrologic behaviour of lake-stream systems, we conducted a study using long-term streamflow data to investigate the annual-, seasonal- and event-scale streamflow regimes of a lake-stream network at the Turkey Lakes Watershed (TLW) in central Ontario, Canada. Streamflow metrics were compared for seven lake and 12 no-lake catchments within the TLW, in addition to 14 no-lake catchments from other forested landscapes. It was difficult to attribute patterns in annual streamflow regimes to the influence of lakes due to the confounding influence of catchment size; however, streamflow regimes appeared to be less flashy at locations with more lake influence. In addition, lake catchments showed high similarity in streamflow regimes across seasons, whereas no-lake catchments showed more similarity to lake catchments during wet seasons but less similarity during dry seasons. Event-scale streamflow regimes further downstream from lake outlets were associated with greater increases in peakflow response and hydrograph rise rate following rain events than locations closer to lake outlets. Antecedent conditions were also important for both the peakflow response and rise rate, but less so than the amount of rainfall during the event. Variability in streamflow across lake-stream networks appears to be driven by interactions between delayed contributions from lakes and relatively rapid runoff contributions from hillslopes and tributaries without lakes. In addition, streamflow regimes are influenced by temporal changes in lake storage deficits, which are a function of lake and catchment properties, as well as hydrometeorological conditions. Our results highlight that a network-scale perspective that incorporates lakes and streams is needed to understand how these landscapes will hydrologically respond to environmental change. |
| |
| Keywords: | forest hydrology lakes rainfall stream network streamflow streams |
|
|
