# properties.monitoring_location_id.description
A unique identifier representing a single monitoring location. This corresponds to the `id` field in the `monitoring-locations` endpoint. Monitoring location IDs are created by combining the agency code of the agency responsible for the monitoring location (e.g. USGS) with the ID number of the monitoring location (e.g. 02238500), separated by a hyphen (e.g. USGS-02238500).

# properties.agency_code.description
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 at [https://api.waterdata.usgs.gov/ogcapi/v0/collections/agency-codes/items](https://api.waterdata.usgs.gov/ogcapi/v0/collections/agency-codes/items).

# properties.agency_name.description
The name of the agency that is reporting the data.

# properties.monitoring_location_number.description
Each monitoring location in the USGS data base has a unique 8- to 15-digit identification number.

# properties.monitoring_location_name.description
This is the official name of the monitoring location in the database. For well information this can be a district-assigned local number.

# properties.district_code.description
The Water Science Centers (WSCs) across the United States use the FIPS state code as the district code. In some case, monitoring locations and samples may be managed by a water science center that is adjacent to the state in which the monitoring location actually resides. For example a monitoring location may have a district code of 30 which translates to Montana, but the state code could be 56 for Wyoming because that is where the monitoring location actually is located.

# properties.country_code.description
The code for the country in which the monitoring location is located.

# properties.country_name.description
The name of the country in which the monitoring location is located.

# properties.state_code.description
State code. A [two-digit ANSI code](https://www2.census.gov/geo/docs/reference/state.txt) (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.](https://www.census.gov/library/reference/code-lists/ansi.html#states) The only countries with political subdivisions other than the US are Mexico and Canada. The Mexican states have US state codes ranging from 81-86 and Canadian provinces have state codes ranging from 90-98.

# properties.state_name.description
The name of the state or state equivalent in which the monitoring location is located.

# properties.county_code.description
The code for the county or county equivalent (parish, borough, etc.) in which the monitoring location is located. A list of codes is available at [https://api.waterdata.usgs.gov/ogcapi/v0/collections/counties/items](https://api.waterdata.usgs.gov/ogcapi/v0/collections/counties/items).

# properties.county_name.description
The name of the county or county equivalent (parish, borough, etc.) in which the monitoring location is located. [A list of codes is available at [https://api.waterdata.usgs.gov/ogcapi/v0/collections/counties/items](https://api.waterdata.usgs.gov/ogcapi/v0/collections/counties/items).

# properties.minor_civil_division_code.description
Codes for primary governmental or administrative divisions of the county or county equivalent in which the monitoring location is located.

# properties.hydrologic_unit_code.description
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.

# properties.basin_code.description
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 monitoring location is located.

# properties.altitude.description
Altitude of the monitoring location referenced to the specified Vertical Datum.

# properties.altitude_accuracy.description
Accuracy of the altitude, in feet. An accuracy of +/- 0.1 foot would be entered as “.1”. Many altitudes are interpolated from the contours on topographic maps; accuracies determined in this way are generally entered as one-half of the contour interval.

# properties.altitude_method_code.description
Codes representing the method used to measure altitude.

# properties.altitude_method_name.description
The name of the method used to measure altitude.

# properties.original_horizontal_datum.description
Coordinates are published in EPSG:4326 / WGS84 / World Geodetic System 1984. This field indicates the original datum used to determine coordinates before they were converted. A list of codes is available at [https://api.waterdata.usgs.gov/ogcapi/v0/collections/coordinate-datum-codes/items](https://api.waterdata.usgs.gov/ogcapi/v0/collections/coordinate-datum-codes/items).

# properties.original_horizontal_datum_name.description
Coordinates are published in EPSG:4326 / WGS84 / World Geodetic System 1984. This field indicates the original datum used to determine coordinates before they were converted. A list of codes is available at [https://api.waterdata.usgs.gov/ogcapi/v0/collections/coordinate-datum-codes/items](https://api.waterdata.usgs.gov/ogcapi/v0/collections/coordinate-datum-codes/items).

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

# properties.contributing_drainage_area.description
The contributing drainage area of a lake, stream, wetland, or estuary monitoring location, in square miles. This item should be present only if the contributing area is different from the total drainage area. This situation can occur when part of the drainage area consists of very porous soil or depressions that either allow all runoff to enter the groundwater or traps the water in ponds so that rainfall does not contribute to runoff. A transbasin diversion can also affect the total drainage area.

# properties.time_zone_abbreviation.description
A short code describing the time zone used by a monitoring location.

# properties.uses_daylight_savings.description
A flag indicating whether or not a monitoring location uses daylight savings.

# properties.aquifer_code.description
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).

# properties.national_aquifer_code.description
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. Not all groundwater monitoring locations can be associated with a National Aquifer. Such monitoring locations will not be retrieved using this search criteria. A list of National aquifer codes and names is available at [https://api.waterdata.usgs.gov/ogcapi/v0/collections/national-aquifer-codes/items](https://api.waterdata.usgs.gov/ogcapi/v0/collections/national-aquifer-codes/items).

# properties.aquifer_type_code.description
Describes the confinement status of an aquifer at the monitoring location. A confined aquifer is an aquifer below the land surface that is saturated with water. A water table--or unconfined--aquifer is an aquifer whose upper water surface (water table) is at atmospheric pressure, and thus is able to rise and fall.

# properties.well_constructed_depth.description
The depth of the finished well, in feet below land surface datum. Note: Not all groundwater monitoring locations have information on Well Depth. Such monitoring locations will not be retrieved using this search criteria.

# properties.hole_constructed_depth.description
The total depth to which the hole is drilled, in feet below land surface datum. Note: Not all groundwater monitoring locations have information on Hole Depth. Such monitoring locations will not be retrieved using this search criteria.

# properties.depth_source_code.description
A code indicating the source of water-level data.

# properties.id.description
The ID of the time series or field measurement series (identified by `data_type`) that collection metadata corresponds to.

# properties.unit_of_measure.description
A human-readable description of the units of measurement associated with an observation.

# properties.parameter_code.description
Parameter codes are 5-digit codes used to identify the constituent measured and the units of measure. A complete list of parameter codes and associated groupings can be found at [https://api.waterdata.usgs.gov/ogcapi/v0/collections/parameter-codes/items](https://api.waterdata.usgs.gov/ogcapi/v0/collections/parameter-codes/items).

# properties.statistic_id.description
A code corresponding to the statistic an observation represents. Example codes include 00001 (max), 00002 (min), and 00003 (mean). A complete list of codes and their descriptions can be found at [https://api.waterdata.usgs.gov/ogcapi/v0/collections/statistic-codes/items](https://api.waterdata.usgs.gov/ogcapi/v0/collections/statistic-codes/items).

# properties.last_modified.description
The last time a record was refreshed in our database. This may happen due to regular operational processes and does not necessarily indicate anything about the measurement has changed.
You can query this field using date-times or intervals, adhering to RFC 3339, or using ISO 8601 duration objects. Intervals may be bounded or half-bounded (double-dots at start or end).
Examples:

  - A date-time: "2018-02-12T23:20:50Z"
  - A bounded interval: "2018-02-12T00:00:00Z/2018-03-18T12:31:12Z"
  - Half-bounded intervals: "2018-02-12T00:00:00Z/.." or "../2018-03-18T12:31:12Z"
  - Duration objects: "P1M" for data from the past month or "PT36H" for the last 36 hours

Only features that have a `last_modified` that intersects the value of datetime are selected.

# properties.begin.title
Time series first observation timestamp - UTC

# properties.begin.description
The datetime of the earliest observation in the time series. Together with `end_utc`, this field represents the period of record of a time series. Note that some time series may have large gaps in their collection record.
You can query this field using date-times or intervals, adhering to RFC 3339, or using ISO 8601 duration objects. Intervals may be bounded or half-bounded (double-dots at start or end).
Examples:

  - A date-time: "2018-02-12T23:20:50Z"
  - A bounded interval: "2018-02-12T00:00:00Z/2018-03-18T12:31:12Z"
  - Half-bounded intervals: "2018-02-12T00:00:00Z/.." or "../2018-03-18T12:31:12Z"
  - Duration objects: "P1M" for data from the past month or "PT36H" for the last 36 hours

Only features that have a `begin_utc` that intersects the value of datetime are selected.

# properties.end.title
Time series most recent observation timestamp - UTC

# properties.end.description
The datetime of the most recent observation in the time series. Data returned by this endpoint updates at most once per day, and potentially less frequently than that, and as such there may be more recent observations within a time series than the time series `end_utc` value reflects. Together with `begin_utc`, this field represents the period of record of a time series. It is additionally used to determine whether a time series is "active".
You can query this field using date-times or intervals, adhering to RFC 3339, or using ISO 8601 duration objects. Intervals may be bounded or half-bounded (double-dots at start or end).
Examples:

  - A date-time: "2018-02-12T23:20:50Z"
  - A bounded interval: "2018-02-12T00:00:00Z/2018-03-18T12:31:12Z"
  - Half-bounded intervals: "2018-02-12T00:00:00Z/.." or "../2018-03-18T12:31:12Z"
  - Duration objects: "P1M" for data from the past month or "PT36H" for the last 36 hours

Only features that have a `end_utc` that intersects the value of datetime are selected.

# properties.data_type.description
The computational period type of data collected at the monitoring location.

# properties.computation_identifier.description
Indicates the computation performed to calculate this time series. Values of "Instantaneous" reflect point measurements.

# properties.thresholds.description
Thresholds represent known numeric limits for a time series, for example the historic maximum value for a parameter or a level below which a sensor is non-operative. These thresholds are sometimes used to automatically determine if an observation is erroneous due to sensor error, and therefore shouldn't be included in the time series.

# properties.sublocation_identifier.description
An optional human-readable identifier used to specify where measurements are recorded at a monitoring location.

# properties.primary.description
A flag identifying if the time series is a "primary" time series. "Primary" time series (which have this flag) are standard observations which undergo [Bureau review and approval processes](https://www.usgs.gov/survey-manual/5028-fundamental-science-practices-review-and-approval-scientific-data-release). Non-primary time series, which will have missing values for "primary", are provisional datasets made available to meet the need for timely best science and to assist with daily operations which need real-time information. Non-primary time series data are only retained by this system for 120 days. See the [USGS Provisional Data Statement](https://waterdata.usgs.gov/provisional-data-statement/) for more information.

# properties.web_description.description
An optional description of the time series. WDFN and other USGS data dissemination products use this field, in combination with sublocation_identifier, to distinguish the differences between multiple time series for the same parameter code, statistic code, and monitoring location.

# properties.parameter_description.description
A description of what the parameter code represents, as used by WDFN and other USGS data dissemination products.

# properties.parent_time_series_id.description
The unique identifier representing the parent or "upchain" time series that a daily values time series is generated from. Daily values time series have one and only one parent time series.