Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Geological Survey.
Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in ARC/INFO format, this metadata file may include some ARC/INFO-specific terminology. Users are cautioned not to be confused by this terminology. This metadata file should contain enough information to eliminate any confusion caused by the use of ARC/INFO-specific terminology.
Nutrient stream-loading estimates were derived from water-quality and flow data collected by State and Federal agencies (Langland and others, 1995) using the methods described in Smith and others (1997). Load-estimate regressions were fit on the basis of actual flow and concentration data. Loads were then estimated using those regressions and an average discharge time series (average daily flow values for the period 1950 to 1995), specifying the year 1987 for the trend component. By use of this method, load estimates may differ from those previously published because of the average discharge values used as input for the regressions. Nutrient stream loads were estimated for total nitrogen, total phosphorus, nitrate/nitrite, amonium, phosphate, and total suspended soilds at as many as 109 sites within the Chesapeake Bay watershed (figure 2). The nitrogen (79 sites) and phosphorus (94 sites) load estimates were used as the dependent variables in the calibration of the SPARROW models. Other nutrient-load estimates may be used for calibration in future applications of the SPARROW models.
Latitude and longitude coordinates of the streamflow sampling sites used for nutrient stream-load estimates were obtained from the USGS National Water Information System (NWIS) and used to generate a point-location data set. Attributes for this point data set consist of a station identification number for the streamflow sampling sites and their associated water-quality sites, and 1987 load estimates for total nitrogen and total phosphorus.
Q_SIT.PAT:
COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME
1 AREA 4 12 F 3
5 PERIMETER 4 12 F 3
9 Q_SIT# 4 5 B -
13 Q_SIT-ID 4 5 B -
17 STAID 15 15 C -
32 QWSTAID 15 15 C -
47 ERF1## 4 5 B -
51 TN 8 18 F 2
59 TP 8 18 F 2
STAID - USGS Station Identification number where
flow data was collected
QWSTAID - Agency Station Identification number where
water-quality data was collected
ERF1## - New unique reach identifier
TN - 1987 load estimates of Total Nitrogen, in kg/yr
TP - 1987 load estimates of Total Phosphorus, in kg/yr
Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data.
The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials.
Generated by mp on Tue Sep 22 13:02:53 1998