The U.S. Geological Survey (USGS) has played important roles in advancing the science of rivers and in order to help assure that its activities continue to serve the nation well, the agency sought advice from the National Research Council (NRC) as to how it might best address river science challenges by effectively using its resources and coordinating its activities with other agencies. In response, the NRC Committee on River Science at the USGS was formed to carry out the tasks shown in Box S-1. This report contains the results of that study.
The committee addresses the first task (i.e., to identify the highest priority river science questions for the USGS) in Chapter 4. This chapter proposes three topical areas, namely, environmental flows and river restoration, sediment transport and geomorphology, and groundwater surface-water interactions, for special emphasis. It also recommends two crosscutting science activities, namely, surveying and mapping the nation’s river systems according to key physical and landscape features and expanding work on predictive models, especially those that simulate interactions between physical-biological processes.
Most of the second task (i.e., to identify key variables to be monitored and data-managed) is addressed in Chapter 5. Table 5-1 summarizes some key recommended variables. The chapter proposes enhancements in streamflow, biological, and sediment monitoring; these include establishing multidisciplinary, integrated reach-scale monitoring sites and developing a comprehensive national sediment monitoring program. It also encourages the USGS to be at the forefront of new technology application, including airborne lidar and embedded, networked wireless sensors.
The answers to most elements of the third task—which asks the committee to balance temporal and spatial scales, local intense studies vs. broad regional or national studies, and work on small, pristine streams vs. large, heavily impacted rivers—are topic specific. Thus, they are different for each individual recommendation. Establishment of the recommended reach-scale monitoring sites, and increased work in groundwater and surface-water interactions, imply local intense study of processes. In contrast, recommended river surveying and sediment monitoring programs would be national in scale and might last for many decades or even centuries. Overall, most of the recommended research areas, such as stream restoration, environmental flows, and models that predict ecological change, imply considerable work in highly altered rivers. However, most of these would benefit from and may require comparative sites in more pristine environments. Thus, the committee defers the details of this task to the USGS pending how it chooses to organize its scientific disciplines to most effectively address river science issues (see Chapter 6).