tool for assessing ecological condition is the current effort to understand the relationship among land use, climate change, and streamflow alteration and to quantify relations between streamflow alteration and biological impairment (Carlisle et al., 2011).
Overall, the NAWQA ecology program has developed nationally consistent measures of the status of primary producers, macroinvertebrates, and fishes in rivers and streams. This has enabled a more complete and integrated assessment of the health of rivers and streams than would be possible with physical and chemical analyses alone. NAWQA’s application of regression analysis and modeling of ecological data have facilitated identification of indicators and indices and may allow the development of predictive models. NAWQA’s urban studies have contributed to the scientific community’s efforts to advance integrative scientific understanding of urban streams (e.g., Wenger et al., 2009).
NAWQA’s National Synthesis Assessments and capstone reports use descriptive statistics to compare study unit data and other historical data (i.e., land use) to draw broad conclusions for the nation—a unique niche for NAWQA. National synthesis teams are able to write these reports because each NAWQA investigation adheres to a nationally consistent study design and employs uniform methods of data collection and analysis. NAWQA’s ability to organize itself around these themes in contrast to a more traditional project-by-project approach represents a major organizational accomplishment. These reports help answer the original NAWQA question: what is the state of our nation’s water quality? These reports identify water quality issues that occur only in isolated areas versus those that are pervasive, and they show the effects of human activities and natural factors on water quality in a range of environmental settings. Three national synthesis reports have been published (pesticides, VOCs, and nutrients), one is in progress (ecology), and the fate of the fifth (trace elements) is unclear.
The Pesticide National Synthesis Project4 and corresponding national synthesis report, Pesticides in the Nation’s Streams and Ground Water, 1992-2001, provides information about the occurrence of 75 pesticides and 8 pesticide degradates in agricultural, urban, undeveloped, and mixed land-use areas (Gilliom et al., 2006). Analytical methods “were designed to measure concentrations as low as economically and technically feasible,” and results were assessed using human health, aquatic-life, and wildlife benchmarks. Pesticide concentrations in streams and groundwater were characterized by land use and geographic patterns in pesticide use as well