described substantively in Chapter 3. Each of these priority areas addresses actions that would improve the scientific foundation and enhance the scope of river science.
The first two science priority areas are crosscutting activities that would strengthen the holistic river science approach. These translate into recommendations for the USGS to (1) conduct a national inventory to survey and map the nation’s stream and river systems according to key landscape features that act as determinants of hydrologic, geomorphic, and ecological processes in streams and rivers and (2) develop conceptual and predictive models that could be used to couple surface water, groundwater, geochemistry, and sediment fluxes, and to quantify ecological responses.
Although we pose these crosscutting science priority areas individually, there is great potential for these activities to enhance each other. A national river science survey would provide a framework or template through which the multiple disciplines within river science could communicate both monitoring information and model results about rivers across the landscape. Additionally, modeling river processes can help indicate the key variables that are most important to monitor and synthesize nationally. Thus, these activities would underpin the USGS’s science contribution to a broad national effort in river science.
In addition to suggesting ways to enhance the interdisciplinary river science vision, the committee has identified three areas of river science for which improved knowledge and understanding is needed, and for which the USGS can play a leading role. These are (1) the characterization of environmental flows in rivers (flow levels and patterns necessary to maintain healthy aquatic ecosystems), (2) basic research, synthesis, and monitoring of fluxes (bed load and suspended load) and their relation to channel dynamics, and (3) full integration of floodplain processes and groundwater hydrology as a basic component of river systems. Investigations into each of these topical science activities are more targeted, both in their geographic extent and specific processes monitored, than the crosscutting activities, although each of these science activities would involve enhanced monitoring and modeling and would be key components of the overall river science framework.
In each section below, the committee outlines the science recommendation and then expands on this recommendation by addressing four overarching questions:
Why is the recommendation in the national interest?
Why should the USGS be involved in this river science issue?
What is a compelling problem related to the recommendation?
What are some examples on how the USGS might do this?