A particular strength of WRD is its capability for multi and interdisciplinary approaches to the analysis of the components of the hydrologic cycle and its management. For example, the agency monitors the quantities and quality of surface and groundwaters. In recent years, it has extended its concern “upstream” by linking these measurements with information on rainfall, snowmelt, and the conditions of watersheds through empirical analysis of data collected by other agencies and by development of its own modeling capabilities to address both land use effects and climate change on water resources. Looking “downstream” within the hydrologic cycle, the agency is involved in data collection on the water quality and ecological functioning of natural and impacted aquatic ecosystems. It continues to expand its analysis of water availability and use, as well as the functioning and restoration potential of large coastal water bodies such as San Francisco Bay, the California Bay-delta, Chesapeake Bay, the Mississippi Delta, and the Florida Everglades (Chapter 2). The involvement of WRD in the linked systems that constitute our water resources and their management problems, from climate to the sea, positions the agency as a critical contributor and potentially a leader of efforts to advise governments and the public in addressing the expanding water-related issues.
The interdisciplinary nature of the WRD can also provide flexibility, which ideally can allow the agency to adjust rapidly to emerging concerns, whether they are the environmental role of new chemicals or nanoparticles, atmospheric connections that affect regional-scale water resources, or the terrestrial and atmospheric linkages associated with warming of boreal regions. The broad geographic reach of WRD, with its offices in all fifty states also means that the agency has a means of keeping its finger on the pulse of changes in water resources and their use across the country and the potential to recognize changes and emerging issues at an early stage. The agency is also well-placed to participate in, or even facilitate constructive resolution of interstate water-resource conflicts because it is involved in monitoring and analyzing the behavior of water resources (rivers, lakes, and aquifers) that cross state boundaries.
What we are describing is a long-standing WRD tradition of studying the impact of human activities on natural resources such as land, water resources, and ecosystems. This fundamental tradition facilitates, not only thorough effective assessments by the agency itself, and it prepares WRD personnel to collaborate with and even to provide interdisciplinary leadership among other agencies, that generally have a more narrow disciplinary focus in, for example, atmospheric science, or land and wildlife management. The issue of whether society can manage resources sustainably in the face of population growth, wealth production, and climatic uncertainty