River Science at the U.S. Geological Survey (2007) / Chapter Skim
Currently Skimming:
2 Major River Science Drivers and Challenges
2 Major River Science Drivers and Challenges
Pages 25-40
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 25... ...
. Simultaneously, expectations to maintain and restore the natural functioning of the nation's river ecosystems are increasing.
|
From page 26... ...
, relicensing of hydropower facilities, invasive species, water allocation, climatic variability, urbanization and other land-use changes, and water quality. We also mention briefly the economic value of river ecosystem services, a matter that is particularly relevant when the case for river science is rationalized based on the values rivers provide.
|
From page 27... ...
The current effort -- known as the USGS Platte River Ecosystem Initiative -- involves all four disciplines within the USGS (Biological Resources, Geologic, Geographic, and Water Resources)
|
From page 28... ...
Authorization to remove these two dams comes from the Elwha River Ecosystem and Fisheries Restoration Act, passed by Congress in 1992 to restore the natural system. As the name of the act implies, the primary purpose of dam removal is to restore the ecosystem and na tive salmon fisheries of the Elwha River system.
|
From page 29... ...
Other research frontiers include determining how best to restore ecosystem processes under highly constrained conditions that surround dams and levees or in urban settings, how to move some aquatic ecosystems beyond "restoration" to boost their ability to perform functions of value to society, and how to identify feedbacks associated with critical thresholds beyond which river restoration is not possible (Palmer and Bernhardt, 2006)
|
From page 30... ...
These more involved analyses consider how the altered flow regime modifies the normal distribution of high and low flows and investigates how the flows influence a much broader suite of species and affect the entire aquatic ecosystem. Still more work is needed to gain a predictive understanding of the linkages between flow variations and river habitat in highly regulated rivers.
|
From page 31... ...
. Since its introduc tion in the 1800s, Tamarisk is now the third most common woody riparian plant species in western river ecosystems in North America (Friedman et al., 2005)
|
From page 32... ...
. However, a better understanding of the habitat needs of species throughout their life cycle and the BOX 2-5 Water Allocation and River Restoration: The San Joaquin River, California The San Joaquin River, the second longest river in California, has been the focus of a recent water allocation controversy.
|
From page 33... ...
While there may not be complete agreement on the anthropogenic contribution to climate change, the evidence of significant climate variation both from the modern instrumental record and from historical reconstructions from tree rings and other paleoclimate data is indisputable. Streamflow variability in the western United States is strongly tied to large-scale interannual and interdecadal climate oscillations (Redmond and Koch, 1991; Kahya and Dracup, 1993; Dracup and Kahya, 1994)
|
From page 34... ...
Understanding and predicting the impacts of climatic variability and change on river flow regimes and flood frequencies is only one of the challenges. A chang ing hydrologic regime would also put a greater strain on water resources manage ment.
|
From page 35... ...
Therefore, an improved understanding of the role of large-scale climate oscillations and trends on streamflow timing and seasonality is needed. With an improved ability to forecast short-term seasonal and interseasonal climate variations, there are more opportunities to better manage water resources for aquatic species, particularly in the context of adaptive management experiments (Pulwarty and Redmond, 1997; Pulwarty and Melis, 2001)
|
From page 36... ...
Therefore, our ability to accurately predict and manage floods or to estimate water availability is limited by our understanding of these minor changes. Current federal regulations governing flood insurance generally do not require the consideration of future conditions, although there is a movement toward including predictions of future riverine hydrology in flood stage predictions.
|
From page 37... ...
Economic approaches to valuing river ecosystem services are particularly relevant when the case for river science is rationalized based on the value rivers provide, and thus ultimately underlies all the drivers and challenges noted above. Given, however, that the USGS does not have an economic analysis capacity, and the development of one is not envisaged in the near future, we do not expand on this here but briefly address valuation methods and their challenges in Appendix A
|
From page 38... ...
While this research has been extremely valuable, it is insufficient to answer questions about the processes affecting sediment movement in major rivers or hypoxia in the Gulf of Mexico. Rivers integrate the multitude of spatially distributed, smallscale alterations to the landscape and waterways, and awareness of such cumulative impacts must guide the vision for river science.
|
From page 39... ...
Some examples of recently established interdisciplinary programs include the National Science Foundation's Biocomplexity in the Environment Program, Environmental Protection Agency's Water and Watersheds Program, and National Oceanic and Atmospheric Administration's Climate and Global Change Program. Other proposals for developing major interdisciplinary research programs at the National Science Foundation are on the table and may soon be underway; these include National Ecological Observatory Network (NEON)
|
From page 40... ...
River science -- an emerging discipline distinct from traditional disciplinary sciences but still supported by their activities -- can provide a vision for organizing scientific endeavors to address these unique challenges. Recommendation: USGS river science activities should be driven by the compelling national need for an integrative multidisciplinary science structured and conducted to develop a process-based pre dictive understanding of the functions of the nation's river systems and their responses to natural variability and the growing, perva sive, and cumulative effects of human activities.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.