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Search criteria and codes

Search criteria are criteria that you enter to select sites of interest. Codes describe data and aid in its interpretation. This page contains links to a comprehensive set of codes used by this site which can be used an an authoritative reference.

Site Criteria | Site Inventory Codes | Groundwater Codes | Surface Water Codes | Water Quality Codes

Definitive list of USGS parameters

Site Criteria

Site criteria let you find sites of interest. Site criteria pages exist for current conditions, site information, surface water, groundwater and water quality data. Not all criteria listed below can be used for all data categories.

  • Agency code
The agency that is reporting the data. Agency codes are fixed values assigned by the National Water Information System (NWIS). A list of agency codes is available. [ Tab-separated -- saved to file || HTML ]
  • Altitude
Altitude of the site referenced to the specified Vertical Datum.
  • Aquifer type
Groundwater occurs in aquifers under two different conditions. Where water only partly fills an aquifer, the upper surface is free to rise and decline. These aquifers are referred to as unconfined (or water-table) aquifers. Where water completely fills an aquifer that is overlain by a confining bed, the aquifer is referred to as a confined (or artesian) aquifer. When a confined aquifer is penetrated by a well, the water level in the well will rise above the top of the aquifer (but not necessarily above land surface). Additional information is available.
  • CASRN
  • Construction date
Date the well was completed.
  • County
The name of the county or county equivalent (parish, borough, etc.) in which the site is located. A list of codes is available. [ Tab-separated -- saved to file || HTML ]
  • Data type
All USGS data falls into one or more of these categories
Any Data type Matches data for any available options
Current Conditions and Recent Daily Data Current condition data is any data down to the 15 minute interval that has been transmitted in the last 120 days. Recent Daily-Value Data is the average daily value for a site and it is usually for the past year and a half of recorded values.
Surface Water Water flow and levels in streams, lakes and springs.
Water Quality Chemical and physical data for streams, lakes, springs, and wells.
Groundwater Water levels in wells.
  • 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.
  • File of site numbers
A previously saved file of USGS site identification numbers, in the format:
USGS 11447650
USGS 394523084582301
The file may be prefixed by the agency code.
  • File of parameter codes
A previously saved file of parameter codes, in the following format:
01130	Minor and Trace Inorganics	Lithium, water, filtered, micrograms per liter
01131	Minor and Trace Inorganics	Lithium, suspended sediment, recoverable, micrograms per liter
01132	Minor and Trace Inorganics	Lithium, water, unfiltered, recoverable, micrograms per liter
List of parameter code names, and help finding a code.
  • Groundwater site type- subset of Site Type, site types used by groundwater
The code indicating the type of site to which these data apply. The codes and their meanings are available.
  • Hole depth
The total depth to which the hole was initially drilled, in feet below land surface datum.
Note: Not all groundwater sites have information on Hole Depth. Such sites will not be retrieved using this search criteria.
  • Hydrologic region
The contiguous United States is broken into 18 different major watersheds. Alaska, Hawaii, and Puerto Rico each have a separate watershed. Additional information is available.
  • 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. Additional information is available.
Note: Not all groundwater sites have been associated with a Hydrologic Unit. Such sites will not be retrieved using this search criteria.
  • (Internal) Site list
A previously saved file of USGS site identification numbers. This option should only appear on displays if the user is inside the USGS network.
  • Latitude-Longitude (Lat-Long) box
When looking at a map, consider a rectangle that encloses the area of interest to you. The maximum latitude and longitude define the upper-left corner, and the minimum latitude and longitude define the lower-right corner of that box. To find the approximate latitude and longitude try the USGS MapFinder. For the best results define the smallest practical latitude-longitude box that includes the area of interest; retrievals from unnecessarily large latitude-longitude boxes (1x1 degree, for example) may yield many undesired sites.
Examples
Degrees-
Minutes-
Seconds
Decimal
Degrees
100 59 01 100.91
45 09 34 45.11
  • Local aquifer (by code)
Local aquifers in the USGS water resources data base are identified by a geohydrologic unit code (a three-digit number related to the age of the formation, followed by a 4 or 5 character abbreviation for the geologic unit or aquifer name). Additional information is available. [ Tab-separated -- saved to file || HTML ]
Note: Not all groundwater sites have been associated with a Local Aquifer. Such sites will not be retrieved using this search criteria.
  • Local aquifer (by name)
Name of the aquifer. Also known as the geohydrologic unit. Additional information is available.
Note: Not all groundwater sites have been associated with a Local Aquifer. Such sites will not be retrieved using this search criteria.
Local aquifer codes and names are fixed values assigned by the National Water Information System (NWIS). A list of aquifer codes and names is available. [ Tab-separated -- saved to file || HTML ]

  • Multiple site numbers
A list of multiple site numbers separated by carriage returns (generated by pressing the ENTER key on your keyboard) are used to display many sites simultaneously. Each site in the USGS data base has a unique 2 to 15-digit identification number. You can search using an exact match or match using a partial number. To use an exact match you must include all of the digits including any leading zeros (0) that make up the complete site number. A site will not be found if the site number has a leading zero and it is not included in the string tested using an exact match.
Note: The speed of the search using site numbers (and site names) is very fast using exact matches. The next fastest is matching from the beginning. Searches that match any part of the number (or name) are much slower.
  • National aquifer
National aquifers are the principal aquifers or aquifer systems in the United States, defined as regionally extensive aquifers or aquifer systems that have the potential to be used as a source of potable water.
Most of the national aquifers were published on the map sheet Principal Aquifers, part of the National Atlas of the United States of America. A few additional national aquifers were added from descriptions in the Groundwater Atlas of the United States. The aquifer names are regional names, and may not reflect local names used to refer to an aquifer. National aquifers are identified in the USGS water resources database using the codes available here.
Note: Not all groundwater sites can be associated with a National Aquifer. Such sites will not be retrieved using this search criteria.
A list of National aquifer codes and names is available. [ Tab-separated -- saved to file || HTML ]
  • Number of observations
Number of records found meeting a given criteria.
  • Parameter code/name
  • Parameter groupings
Parameters are grouped into major categories of water-quality data. Each parameter belongs to one group only. Parameter codes associated with each group.
  • Period of record
Period of record for the data selected. You can enter either or both of the first date or end date to restrict search. The search is done against the first and last date of record for the given type of data, not against the actual data values. Thus, if a site has one sample collected on 1910-01-01 and all following samples collected between 1980-01-01 and 1990-01-01, and the search "first date" is 1950-01-01, this site will pass the test since the period of record for the site would be from 1910-01-01 to 1990-01-01. (NOTE: checking data values explicitly, and not using a summary of the data is time consuming and is not supported currently. )
Dates can be entered in any of the following formats:
FORMATEXAMPLE
YYYY-MM-DD 2000-05-12
YYYY-M-D 2000-5-12
M/D/YYYY 5/12/2000
M D YYYY 5 12 2000
YYYYMMDD 20000512
YYYY.M.D 2000.5.12
  • Sample medium type
Medium type refers to the specific environmental medium that was sampled and analyzed. Medium type differs from site type because one site type, such as surface water, could have data for several media, such as water, bottom sediment, fish tissue, and others. For a listing of the medium types look in the [Codes Help Section]
  • Site name/Local number
This is the official name of the site in the database. For well information this can be a district-assigned local number. Do NOT include "river", "lake", "creek" or other hydrological term. Search for "trinity" not "trinity river", or a complete or partial local number. All name searches are NOT case sensitive.
Note: Site name searches are the slowest way to find sites, and take 5 to 10 times longer than searches using the site number. The fastest site name search is matching from the beginning. Searches that match any part of the name are much slower.
  • Site number
Each site in the USGS data base has a unique 2- to 15-digit identification number. Site numbers are assigned based on this logic. You can search using an exact match or match using a partial site number. To use an exact match you must include all of the digits including any leading zeros (0) that make up the complete site number. A site will not be found if the site number has a leading zero and it is not included in the string tested using an exact match.
Note: The speed of the search using site numbers (and site names) is very fast using exact matches. The next fastest is matching from the beginning. Searches that match any part of the number (or name) are much slower.
  • Site type
The hydrologic setting of the site. This is not equivalent to the type of data collected at the site.
A list of the codes are available. Tab-separated -- saved to file || HTML ]
  • State/Territory
The name of the state or territory in which the site is located.
  • USEPA SRS
  • Update time
The Update time option provides the ability to select sites that have been updated within the last x minutes (or other interval). The available intervals are dependent on the data being queried - Current condition inventory data intervals are minutes, while Site inventory and Streamflow measurements intervals are minutes, days, weeks, months, or years. It should be kept in mind that while most current condition sites record data onsite every 15 minutes, they only transmit those data to the web database every 1 to 4 hours.
  • Water quality method codes
Water Quality method codes are associated with one or many parameter codes. The method codes and associated parameters used in NWIS are available. [ Tab-separated -- saved to file || HTML ]
  • Well depth
The depth of the finished well, in feet below land surface datum.
Note: Not all groundwater sites have information on Well Depth. Such sites will not be retrieved using this search criteria.

Site Inventory Codes

These codes document attributes of sites in the system.

  • Agency codes (agency_cd) - The agency that is reporting the data. Agency codes are fixed values assigned by the National Water Information System (NWIS). Tab-separated -- saved to file || HTML ]
  • Aquifer type code (aqfr_type_cd) - Describes the type of aquifer(s) encountered by a site type of well (groundwater). [ Tab-separated -- saved to file || HTML ]
  • Basin codes (basin_cd) - The Basin Code or "drainage basin code" is a two-digit code that further subdivides the 8-digit hydrologic-unit code. The drainage basin code is defined by the USGS State Office where the site is located.
  • Hydrologic unit codes (huc_cd) - The United States is divided and sub-divided into successively smaller hydrologic units which are classified into four levels: regions, sub-regions, accounting units, and cataloging units. The hydrologic units are arranged within each other, from the smallest (cataloging units) to the largest (regions). Each hydrologic unit is identified by a unique hydrologic unit code (HUC) consisting of two to eight digits based on the four levels of classification in the hydrologic unit system.
  • Lat/Long coordinate accuracy codes (coord_acy_cd) - Indicates the accuracy of the latitude longitude values.
  • Lat/Long coordinate method codes (coord_meth_cd) - Indicates the method used to determine latitude longitude values.
  • Lat/Long in DMS coordinate datum code (coord_datum_cd) - Latitude/longitude (horizontal) coordinate datum.
  • Local aquifer codes (aqfr) - The eight-character string identifying an aquifer. Codes are defined by the "Catalog of Aquifer Names and Geologic Unit Codes used by the Water Resources Division."
  • Local standard time flag (local_time_fg) - Y for yes or an N for no to indicate whether the site is in an area that switches to Local Standard Time (Daylight Savings Time) for a part of the year.
  • National aquifer codes - National aquifers are the principal aquifers or aquifer systems in the United States, defined as regionally extensive aquifers or aquifer systems that have the potential to be used as a source of potable water. [ Tab-separated -- saved to file || HTML ]
  • Site-Type Codes (site_tp_cd) - A list of primary and secondary site types that can be associated with data collection sites. A site type is a generalized location in the hydrologic cycle, or a man-made feature thought to affect the hydrologic conditions measured at a site. All sites are associated with a primary site type, and may additionally be associated with a secondary site type that further describes the location. The exception to this rule is the Facility primary site type, which must always be associated with a secondary site type. The site type code incorporates these hierarchial distinctions. [ Tab-separated -- saved to file || HTML ]
  • State and county Codes (state_cd, county_cd) - State code. A two-digit ANSI code (formerly FIPS code) as defined by the American National Standards Institute, to define States and equivalents. A three-digit ANSI code is used to define counties and county equivalents. A lookup table is available.
  • Time zone codes (tz) - Time zone offset from GMT. An ANSI SQL/92 time zone offset string. Some examples are '-05:00' (Eastern), '+02:00' (Eastern Europe), and '+03:30' (India). [ Tab-separated -- saved to file || HTML ]
  • Topographic setting code (topo_cd) - Refers to the geomorphic features in the vicinity of the site.
  • Type of data collected (data_types_cd) - This is a legacy field from the old WATSTORE days therefore the national consistency of the information/values stored in this field will vary. This field is actually a 30-POSITION ARRAY of characters.

Groundwater Codes

These codes document attributes unique to groundwater sites in the system.

Surface Water Codes

These codes document attributes unique to surface water sites in the system.

Water Quality Codes

These codes document attributes unique to water quality sites in the system.

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Page Last Modified: 2011-11-09 15:04:35 EST