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Abstract: Despite improvements in understanding biophysical response to climate change, a better understanding of how such changes will affect societies is still needed. We evaluated effects of climate change on the coupled human–environmental system of the McKenzie River watershed in the Oregon Cascades in order to assess its vulnerability. Published empirical and modeling results indicate that climate change will alter both the timing and quantity of streamflow, but understanding how these changes will impact different water users is essential to facilitate adaptation to changing conditions. In order to better understand the vulnerability of four water use sectors to changing streamflow, we conducted a series of semi-structured interviews with representatives of each sector, in which we presented projected changes in streamflow and asked respondents to assess how changing water availability would impact their activities. In the McKenzie River watershed, there are distinct spatial and temporal patterns associated with sensitivity of water resources to climate change. This research illustrates that the implications of changing streamflow vary substantially among different water users, with vulnerabilities being determined in part by the spatial scale and timing of water use and the flexibility of those uses in time and space. Furthermore, institutions within some sectors were found to be better positioned to effectively respond to changes in water resources associated with climate change, while others have substantial barriers to the flexibility needed to manage for new conditions. A clearer understanding of these opportunities and constraints across water use sectors can provide a basis for improving response capacity and potentially reducing vulnerability to changing water resources in the region. [Copyright &y& Elsevier]

The article provides information on a study that identified areas of hyporheic exchange on a large, gravel-bed river and investigate their relationship with channel morphological features. It quantifies the amount of hyporheic exchange occurring and estimates how much hyporheic exchange affects overall river temperatures. The study identified a total of 52 temperature anomalies using a combination of field investigations and thermal infrared radiometry (TIR) imagery over summer 2006. The research estimated that existing hyporheic flow in the Clackamas River in Oregon has a minimal impact on daily maximum temperature.

The article discusses hydrogeologic controls on summer stream temperatures in the McKenzie River basin, Oregon. The author states that stream temperature is a complex function of energy inputs such as solar radiation and latent and sensible heat transfer. The article explains that in streams in which groundwater inputs are significant, energy input through advection can be an important control on stream temperature. Researching spatial patterns of a stream's temperature at a landscape scale requires estimating how the environment varies through space and under varying atmospheric conditions.

• Increased sediment transport after forest harvest is not attributable to one process. • Both changes in sediment supply and streamflow may contribute to increased transport. • Long-term paired catchment data suggest increased sediment supply predominates. • Suspended sediment and bedload transport recover at different rates after harvest. • Full recovery to pre-harvest sediment transport conditions may require many decades. The magnitude of sediment yield following forest timber harvest is controlled by increases in both sediment supply and streamflow. Since the relation between sediment transport and streamflow typically follows a power law, small increases in streamflow may translate into large increases in sediment transport. Interpreting the geomorphic effects of streamflow increases is confounded by the fact that timber harvest influences both the hydrologic regime and sediment supply of a watershed simultaneously, making it difficult to isolate the streamflow effect alone. Here we report on a novel approach to this problem using long-term data from two paired catchments located in the H.J. Andrews Experimental Forest, Oregon, USA. We use observed streamflow from the treated (clearcut) and control watersheds to reconstruct a natural streamflow time series for the treated watershed, one that represents streamflow response in conditions prior to harvest. We combine this reconstructed natural streamflow time series with observed relations between streamflow and sediment transport to quantify the background sediment yield and disentangle the relative effects of changes in hydrology and sediment supply. Results indicate that while increases in streamflow can account for modest increases in sediment transport, this is dwarfed by the increased supply of sediment that accompanies most timber harvest. These results have broad relevance to forest timber harvest and fuel management practices worldwide and can be used to constrain or set bounds on likely effects of more modest (i.e., thinning) techniques. [ABSTRACT FROM AUTHOR]