EXPLANATION OF INDEX TABLES

This index lists the sites at which the following data are available: continuous-record stream-gaging stations, crest-stage gage and low-flow partial-record stations; daily chemical, sediment, and temperature stations; stations where chemical, sediment, and biological data have been collected on an intermittent basis; and lakes where chemical, biological, and lake-level data have been collected

For all records prior to 1988, streamflow stations are listed in order of their location in a downstream direction along the main stream.  For all records added after 1988, stations are located at the end of each hydrologic subregion table. Lake sites are grouped by geographical location.

Station Identification

Numbers have been assigned to each station as an added means of identification and are of two types. In the 8-digit number, such as 15008000, the first two digits "15," denote Alaska and the remaining six digits, "008000" indicate downstream order. These assigned numbers are in numerical order but are not consecutive. They are selected from the complete 6-digit number sequence so that intervening numbers will be available for future assignment to new locations.

A 15-digit identification number, which is the original latitude and longitude location plus a 2-digit sequence number, has been assigned to most lake and miscellaneous stream water-quality sites where data have been collected on an intermittent basis. This number may differ from the currently assigned location because of revisions to the topographic maps or adjustments to the original location. These stations are inserted in the standard downstream order.

Name

The station name consists of the name of the stream or lake and in some instances its position relative to another physical feature or the nearest town. The name shown is the most recently used in publications. Another name may have been used in earlier publications.

Location

All station locations have been assigned a latitude and longitude determined from the most recent topographic maps available for the respective areas.

Drainage Area

The drainage area of a stream at a specific point is that area, measured in a horizontal plane, enclosed by a topographic divide from which direct surface runoff from precipitation normally drains by gravity into the stream above the specified point. Drainage areas given herein include all closed basins or noncontributing areas within the area unless otherwise noted.

Surface Area

The surface area of a lake is that area outlined on the latest U.S. Geological Survey topographic map as the boundary of the lake and measured by a planimeter in acres. All areas shown are those for the stage when the planimetered map was made.

Streamflow Stations

Continuous Record: A stream-gaging station for which the discharge or stage data are published on a daily, weekly, or monthly basis for a continuous period of time. Annual extremes of discharge, stage, and low flow are also determined for most stations.

Crest-stage partial record: A station for which only the annual maximum discharge and stage data are published over a period of years.

Low-flow partial record: A station for which measurements of low flow are published. For some stations, measurements made periodically through the year are also included.

Discharge measurements have been made at many ungaged sites and published as "Discharge at Miscellaneous Sites" in the annual data reports. These sites are not included in this index, nor are the data entered in the Survey's computer storage system.

Lake Sites

Sites at which lake-level and (or) water-quality data have been collected, either continuously or on an intermittent basis.

Water-Quality Stations

Chemical: A station at which samples have been collected on either a daily or intermittent (one or more samples per year) basis for one or more of the following constituents: major cations and anions, specific conductance, pH, dissolved oxygen, color, trace metals, nutrients, radiochemicals, or pesticides.

Water temperature: A station at which either continuous or one-daily temperature records have been collected. Water temperatures are also usually measured when discharge measurements are made and water-quality samples are collected, but are not indicated in this report.

Sediment: A station at which samples for analysis of suspended-sediment concentrations and particle-size distributions have been collected on either an intermittent (one or more samples per year) or daily basis.

Biological: A station at which samples have been collected on either a continuous or intermittent basis for analysis of one or more of the following: phytoplankton, periphyton, or benthic invertebrates.

Water-quality data collected at springs have been published and entered in the Survey's computer storage system; these data are not included in this index.

Periods of Record

The periods of record for daily or monthly discharge, chemical, water temperature, sediment, and biological data collected are listed as calendar years in which records began or ended; "breaks" in the records of less than a year are not shown. For example, if a record began in October 1973, stopped in April 1982, began again in March 1983, and ended in September 1994, the period of record would be shown as 1973-94.

The "crest-stage annual peaks" and "low flow" periods of record show the water years for which the record of annual maximum or minimum discharge is available. The water year begins October 1 and ends September 30. In listing the water year, only one date is shown; for example, 1982 stands for water year October 1, 1981, to September 30, 1982.

A date followed by only a dash indicates that the station was continued in operation to the present. A date followed by a semicolon indicates a break in the collection of records. Additional explanatory notes are given in the heading of each table.