Dr. John Rex’s talk, entitled “Small Streams and Big Dreams: Watershed Management Challenges and Opportunities”, highlighted the important of small streams (esp. in stream order S4 and S6), because they are numerous, and influence to the downstream condition by contributing 60 – 80% water into the major watershed which provides the aquatic migration corridor. With low gradient in their nature, those streams were a great place for juvenile fish as well. However, it was very unfortunate that those streams were neglected to protect in conjunction with our current timber harvesting practices. In fact, it might not be that much important to consider before as now. According to overall current situation including absolute land cover change on the landscape and global warming will be highly impacted to our regional hydrologic cycles. Consequently, it impacts our environment and ecosystem seriously that the decision maker needed to be aware of and a protective action may require following.
Throughout presentation, John articulated his presentation together with facts and figures. Most fascinating thing of his study was inclusion of systematic measurement of various parameters such as air and water temperature, and stand high versus canopy shade, and considered the various aspect of those measured data to understand the whole concept of his study. For example, increase in riparian zone proximity (3m to 10m) of fish bearing stream and removal of salvage trees along those streams after natural disasters event will increase the higher proportion of good outcome of stream function and as well as for riparian habitat. Dr. Rex also found that there were strong linkages between forest operation such as harvesting, new road development and the stream function.
Two examples of management effects he brought up into my attention that can be idealized for my research. The first one was the management practices of silviculture activities; forest types, and the size, i.e. mature Douglas Fir stand has higher evapo-transpiration rate, the stream near those area were not much effective into stream flow, they maintain the stream function. The second one was the clear-cut practices on the landscape increase in overall water yield, and high impact on peak water flow in fall season were the big challenge to maintain long term low flow in the stream. As a result, high snow fall, early snow melt will increase the run off in the watershed as well as a threat to the public safety. Higher erosion and deposition rate along the channel will impact on the stream morphology. As the surface water and groundwater have interrelated each other, those activities on landscape will impact to the groundwater system, must pay attention on how will be affected.
John answered all questions well. If I could have a chance, I would have asked John to elaborate the analytical approach of his bull-trout model that I think it has a slight difference from Pacific Northwest Model. I enjoyed the moment of life-long learning and expecting more because knowledge is golden.
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