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Summary of U.S. Geological Survey On-Line Instantaneous Fluvial Sediment Data

Glossary of Terms

Agency Code
The agency that is reporting the data. Agency codes are fixed values assigned by the National Water Information System (NWIS).

The Federal Information Processing Standards (FIPS) code of the county or county equivalent (parish, borough, etc.) in which the site is located.

The U.S. Geological Survey District office that operates the site.

Drainage area
The area enclosed by a topographic divide from which direct surface runoff from precipitation normally drains by gravity into the stream above that point.

Hydrologic Unit Code (HUC)
Hydrologic units are geographic areas representing part or all of a surface drainage basin or distinct hydrologic feature and are delineated on the State Hydrologic Unit Maps. Each hydrologic unit is identified by a unique number (HUC), and a name.

Data for water-quality samples, including suspended sediment, bedload, and bed material, are stored under parameter codes. Each parameter code defines a specific type of data. The USGS and USEPA typically use similar parameter-code definitions, although there are exceptions to this rule. Parameter codes fall into three classes:

  1. Site and sampling-event data, such as site name, site ID, sample data, etc.
  2. Fixed-value codes, which are used to define a certain part of the process of sample collection, processing, or quality assurance.
  3. Chemical, physical, and biological data. The following illustrates how codes are defined, and how for one type of measurement, several parameter codes may exist.

Parameter CodeParameter Definition
70331Sediment, suspended, sieve diameter, percent finer than 0.062 mm
70342Sediment, suspended, fall diameter, distilled water, percent finer than 0.062 mm
80154Sediment, suspended concentration (mg/L)

Station Identification Number
Each site in the data base has a unique 8- to 15-digit identification number.

Station Name
The name of the site in the database.

Definitions of terms used in U.S. Geological Survey Annual Water Data Reports

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Appendix A--Parameter Codes
Appendix B--Selected Retrieval Results
Appendix C--Remark and Value Codes

Figure 1--Locations of Sites with Suspended-Sediment Data
Figure 2--Locations of Sites with Particle-Size Distributions of Suspended-Sediment Data
Figure 3--Locations of Sites with Bedload Discharge Data
Figure 4--Locations of Sites with Particle-size Distribution of Bed Material Data

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