Resource Category: Journal Papers and Book Chapters

This paper presents results from studies of exposure to climate change
and extreme events in the Mendoza River Basin in western Argentina, the
Chinchina´ River basin in the Colombian Andes, and the Oldman River basin and
Swift Current Creek watershed in the Canadian Prairies. These case studies are a
major component of an international research project: “Vulnerability and Adaptation to Climate Extremes in the Americas” (VACEA). This project is very much
interdisciplinary; with social and natural science providing context and direction for
research in the other realm of scholarship, producing insights that very likely would
not arise from a more narrow disciplinary perspective.

Tree-ring-based reconstructions of paleo-hydrology have proved useful for better understanding the irregularities and extent of past
climate changes, and therefore, for more effective water resources management. Despite considerable advances in the field, there
still exist challenges that introduce significant uncertainties into paleo-reconstructions. This study outlines these challenges and
address them by developing two themes: (1) the effect of temporal scaling on the strength of the relationship between the hydrologic
variables, streamflow in this study, and tree growth rates and (2) the reconstruction uncertainty of streamflow due to the dissimilarity
or inconsistency in the pool of tree-ring chronologies (predictors in reconstruction) in a basin.

Natural proxy records of hydroclimatic behavior, such as tree ring chronologies, are a rich
source of information of past climate-driven nonstationarities in hydrologic variables. In this study, we investigate tree ring chronologies that demonstrate significant correlations with streamflows, with the objective
of identifying the spatiotemporal patterns and extents of nonstationarities in climate and hydrology, which
are essentially representations of past ‘‘climate changes.’’ First and second-order nonstationarities are of particular interest in this study. As a prerequisite, we develop a methodology to assess the consistency and
credibility of a regional network of tree ring chronologies as proxies for hydrologic regime.

Communities and economies are vulnerable to the adverse effects of climate
change. This vulnerability is a function of (1) exposure to climate hazards and
their impacts and (2) social conditions that determine (a) sensitivity, the degree to
which a system is affected by climate-related stimuli, and (b) adaptive capacity, the
ability of a system to adjust to climate risks and opportunities by increasing its
resilience or coping range (Smit and Johanna 2006). Adaptive capacity depends on
access to financial, social, and natural resources and institutions, the management of
current and past stresses, and the ability of institutions and individuals to learn from
experience and to anticipate and plan for future change (Armitage 2005). When
exposed to the impacts of climate change, the adaptive response will depend largely
on the capacity of a community to deal with the impacts and risks.

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In this paper the mean water year (October through September) flow of the North
Saskatchewan River (NSR) at Edmonton, Alberta is reconstructed back to 1063 A.D. using a new
network of moisture-sensitive tree-ring chronologies from limber pine and Douglas fir at seven sites in
the headwater sub-basins of the North Saskatchewan River Basin (NSRB). Over the full extent of the
proxy hydrometric record (1063
2007), we examined 1) the duration and severity of low flow, 2) the
dominant frequencies of periodic variability and 3) the correlation between these significant
periodicities in proxy streamflow and climate indices, specifically sea surface temperature oscillations,
which are known drivers of regional hydroclimatic variability. This new record of the paleohydrology
of the NSRB is compared to previous tree-ring reconstructions of the annul flow of the North and
South Saskatchewan Rivers. Extending the reference hydrology for the basin from decades to centuries
changes perceptions of the reliability of the water supply and understanding of the hydroclimatic
variability. The gauge record not does represent the full extent of interannual to multidecadal
variability in the tree-ring data; there are periods of low flow in the pre-instrumental record that are
longer and more severe than those recorded by the gauge.

Fluctuations in size of annual ring-widths of Quercus species suggest that
environmental factors influence the size and density of vessels within the ring, either
by acting as a limiting factor for growth or through fine tuning of the wood structure
to environmental factors. The purpose of this study is to assess the potential of Q.
macrocarpa to provide multiple dendroclimatic proxies for the Canadian Prairies, by
investigating growth responses of annual, early- and latewood widths to regional
climate variability. Results indicate that ring width chronologies, from southeastern
Saskatchewan capture regional signals related to moisture and drought conditions.

Under anthropogenic global warming (AGW) scenarios, southern Alberta, Canada, is projected to see decreased streamflow, and northern Alberta increased streamflow in the next century [Figure 10.12, IPCC 4]. Because of global climate models’ (GCMs) moderate resolution, it is uncertain exactly where the transition between the two hydrological states will occur. Using the observed instrumental records, there has been much recent research on the detection and projection of climate change trends in Alberta and in western Canadian streamflow [i.e., Rood et al., 2005; Schindler and Donahue, 2006; Rood et al., 2008]. The conclusion of this research is that Alberta, particularly southern Alberta, is running out of water due to global warming. In this paper, we critically examine this interpretation of the instrumental records in the northern Rocky Mountains.

Groundwater could be an increasingly important water supply in the Canadian interior with global warming and declining summer runoff; however, not enough is known about the behavior of groundwater
under climatic variability. Groundwater levels at two wells in southern and central Alberta are analyzed
in order to document long-term variability of groundwater levels and their sensitivity to climatic events.
The instrumental well records span more than 40 years. Strong correlations (r > 0.7, p < 0.01) between mean annual groundwater levels and tree-ring chronologies suggested the use of regression models to reconstruct historical water levels for more than 300 years. From the estimated groundwater levels several periods with five or more consecutive years of low levels were identified (i.e. periods centered on 1698, 1720, 1855, and 1863 at well 117; 1887 and 1923 at well 159). The application of a regime shift method revealed periods with more than 30 years with below-average water levels. Spectral analyses, wavelet and multitaper methods, suggest dominant oscillation modes in groundwater levels in the 2–8 and 8–16 year bands

Groundwater could be an increasingly important water supply in the Canadian interior with global warming and declining summer runoff; however, not enough is known about the behavio of groundwater under climatic variability. Groundwater levels at two wells in southern and central Alberta are analyzed in order to document long-term variability of groundwater levels and their sensitivity to climatic events. The instrumental well records span more than 40 years. Strong correlations (r > 0.7, p < 0.01) between mean annual groundwater levels and tree-ring chronologies suggested the use of regression models to reconstruct historical water levels for more than 300 years. From the estimated groundwater levels several periods with five or more consecutive years of low levels were identified (i.e. periods centered on 1698, 1720, 1855, and