July 2008
- Removal of width, area, and velocity from Streamflow Measurements on this site
- More streamflow measurements are now available (No longer limited to only active gaging stations)
- Modified measurement outputs for new improvements (html and rdb)
- Modified measurement symbol on graphs (from X to *) for greater visibility
- Improved Station Name Searching ability (Use quotes for exact matching, allows apostrophes, multiple spaces, and period)
- Peak formats should now be more consistent with qualification codes in all outputs
- Changed peak watstore format name to peakfq
- Implemented new three-character medium codes for water-quality data
- Added links to Instantaneous Data Archive to allow access to long term data
- Added links to Annual Data Report
- Added additional geographic regions: American Samoa, Northern Mariana Islands, Guam
- Format Changes
- Measurements (html, and rdb)
- Peaks (peakfq, html, rdb)
- Discrete water-quality data (html, rdb)
As part of the July 2008 update to this site, the properties of stream width, area, and velocity were removed from the streamflow measurements (surface-water field measurements) available on this site for the following reasons:
The streamflow measurements provided on this site are primarily made in support of continuous stream gaging stations. For this use, it is critical that the measured streamflow is representative of the gaging station at which the measurement was made. Other properties such as width, area, and velocity, however, are not representative of any one location on the stream. In most cases the exact location of the measurement will vary from year to year or measurement to measurement as channel geomorphology or flow conditions change. The measured streamflow is always representative of the stream gaging station, but the other properties are not. In addition, for many measurements the total flow is the sum of several different channels of a stream, each with a width, area, and velocity. It can be misleading to attempt to represent these multichannel measurements because of the overly simplistic display of these complex data and the potential for misuse with a single width, area, and velocity.
The decision to remove width, area, and velocity from this site was predicated by a major expansion in the internal NWIS database to store a much more complete and accurate representation of a discharge measurement, including the location of each measurement and the potential for multiple channels. We do not feel it appropriate to simplify the new internal design into the old this site display due to the problems noted above. We intend to incorporate the new details of discharge measurements into this site as soon as possible. Because of the complexity of the new database design, an updated this site display of measurements to include these data will inherently be more complex and require careful consideration. In the mean time, we have chosen to limit display to those measurement properties most associated with support of continuous stream gaging stations.
We are aware of the importance of providing width, area, and velocity on this site for use in geomorphologic, water-quality, or other studies. Until we can provide an accurate portrayal of these data from the new database design on this site, interested users should request these data directly from USGS Water Science Centers, where the data and its limitations can be adequately explained on a site-by-site basis as necessary.
We regret any inconvenience and will work toward the restoration and clearer presentation of these data as soon as possible.
