Trends in Stream Water-Quality Data in Arkansas during Several Time Periodsbetween 1975 and 1989

摘要

The report describes (1) trends in selected water-quality data for streams inArkansas during selected periods of time and (2) briefly lists potential causes for some of these trends. The report describes the statistical procedures and assumptions used in the trend analysis. The data used were collected by the USGS and ADPCE and are stored in the USGS's National Water Information System data base. Some data were not included in the trend analyses because of indications that the trend analyses might be affected by changes in field or laboratory procedures. Water-quality properties and constituents selected for analysis include physical properties, fecal bacteria, common ions, nutrients, and trace elements.