Repeated observation or sampling at a site, on a scheduled or event basis, for study and analysis. In general, this category excludes sampling programs in which materials are obtained in the field and brought back to a laboratory for study and analysis.
They're abundant in this area, but hard to count reliably. We outline a procedure for estimating the population sizes so that we can determine whether they're increasing or dwindling. We must both listen for their calls and visually confirm them.
Complex report on the interpretation of aeromagnetic data to study hydrogeology of the San Pedro basin, Cochise County, Arizona determining geologic structure, basin fill and depth to water. Online version of a CD-ROM publication.
Previous analysis showed this area to have reduced macroinvertebrate biodiversity, an important measure of ecosystem health. New observations indicate that conditions have improved; report includes methods and results of sampling.
Document on the federally supported interagency National Acid Precipitation Assessment Program (NAPAP) covering research on causes and effects of acid precipitation with the USGS as the lead agency for monitoring wet acid deposition.
The study of petroleum in both the saturated and unsaturated zones, to better understand the processes that control contaminant behavior, and to use this understanding to estimate the future behavior of the contaminants.