New reconstructions of streamflow variability in the South Saskatchewan River Basin from a network of tree ring chronologies, Alberta, Canada

Abstract

In western Canada growing demand for water resources has increased vulnerability to hydrological drought. The near full allocation of water supplies in the Oldman and Bow River subbasins of the South Saskatchewan River Basin has resulted in a moratorium on new surface water licenses. In this region, short instrumental records limit the detection of long‐term hydrological variability. To extend the historical record, we collected 14 new moisture‐sensitive tree ring chronologies and reconstructed the average October through September flow of the Oldman (1618–2004) and South Saskatchewan (SSR) (1400–2004) rivers. Our SSR proxy record updates a previously published reconstruction. While the 20th century is representative of drought frequency over the long term, droughts are of greater severity and duration in the preinstrumental proxy record. A spectral analysis of the reconstructed flows revealed quasiperiodic cycles at interannual to multidecadal scales.

Modes and Forcing of Hydroclimatic Variability in the Upper North Saskatchewan River Basin Since 1063

“…Our results are not directly comparable to previous studies of long-term hydrologic variability in the Saskatchewan River Basin (Case and MacDonald, 2003;Axelson et al, 2009), because we used somewhat different methods to create, calibrate, and validate the tree-ring models; however, the timing of severe low flow years and multidecadal mega-droughts are generally similar among the proxy records. They also are similar in terms of the amount of instrumental streamflow variance explained by the tree rings, about 50%, although according to other measures of model skill and validation and signal strength, our new reconstruction, based on tree-ring data from seven sites and two species, provides better estimation of the past annual flows than the prior reconstruction from treerings from one site in the watershed.…”

“…and Gan, 2006). Lower frequency variability, reflecting the influence of the Pacific Decadal Oscillation (PDO; Gedalof and Smith, 2001;Gray et al, 2003) is evident in our NSR record but it accounts for a larger proportion of the variance in the SSR reconstruction (Axelson et al, 2009).…”

Observed trends and future projections of precipitation and air temperature in the Lake Winnipeg watershed

“…Historically, the western prairie provinces of Canada have been prone to extremes in precipitation including prolonged droughts, such as that of the recent 1999-2004 event (Axelson et al, 2009;Schindler and Donahue, 2006). By contrast, enhanced precipitation and runoff yields in the Winnipeg and Red River catchment area have produced high-magnitude flows into the South Basin over the last couple of decades (Stainton et al, 2007;St.…”

Tree ring based streamflow reconstruction for the Upper Yellow River over the past 1234 years

“…This approach promises to improve our ability to manage and plan the water resources of the area. Based on the accurately dated, continuous, high-resolution, precisely measured ringwidths, and sensitive relations to climate and hydrology, the sampling and replication of tree rings have been widely applied in reconstructing past streamflow [9,11,12]. In recent years, tree-ring based hydrometeorological reconstruction have been developed for many areas of China, such as the Heihe River [13][14][15], Tongtian River [16], Xinjiang [17][18][19], and the Yellow River Basin [10,20].…”