Effects of storm-sampling frequency on estimation of water-quality loads and trends in two tributaries to Chesapeake Bay in Virginia

Original publisher: Richmond, Va.: U.S. Dept. of the Interior, U.S. Geological Survey, 2001. OCLC Number: (OCoLC)271472229 Subject: Water quality -- Chesapeake Bay (Md. and Va.). Excerpt: ... ( A ) 160,000 100-percent data set 80-percent data set ( 54 ) ( 50 ) 120,000 80,000 40,000 0 COND 160,000 40-percent data set 60-percent data SEset ( 33 ) ( 43 ) PER 120,000 FEET CUBIC80,000 IN DISCHARGE, 40,000 0 160,000 20-percent data set 0-percent data set ( 20 ) ( 0 ) 120,000 80,000 40,000 0 1991 1991 1992 1995 1998 1999 1992 1995 1998 1999 1990 1996 1993 1990 1993 1996 1994 1997 1994 1997 EXPLANATION DAILY MEAN DISCHARGE INSTANTANEOUS DISCHARGE AT TIME OF WATER-QUALITY SAMPLE ( 43 ) PERCENTAGE OF STORM SAMPLES IN THE DATA SET Figure 3. Water-quality samples and daily mean discharge at James River monitoring station for each storm data set, 1990 through 1995 ( A ) and 1995 through 1999 ( B ). James River Load Estimates 15