Glossary ======== +-------------------+------------------------------+---------------------------------------+ | Term | Definition | Reference | +===================+==============================+=======================================+ | .. _cllabel: | A continuous 12-month period | `Hammond et al. (2022)`_ | | | selected to present data | | | Climate Year | relative to climatic | | | | phenomena during which the | | | | annual low-flow period | | | | normally occurs. The climate | | | | year used by the U.S. | | | | Geological Survey runs from | | | | April 1 to March 31, and is | | | | designated by the year in | | | | which it ends. | | +-------------------+------------------------------+---------------------------------------+ | Cubic feet per | A rate of the flow, in | `USGS Water Science Glossary`_ | | second (cfs) | streams and rivers, for | | | | example. It is equal to a | | | | volume of water one foot | | | | high and one foot wide | | | | flowing a distance of one | | | | foot in one second. One | | | | "cfs" is equal to 7.48 | | | | gallons of water flowing | | | | each second. | | +-------------------+------------------------------+---------------------------------------+ | Discharge | The volume of water that | `USGS Water Science Glossary`_ | | | passes a given location | | | | within a given period of | | | | time. Usually expressed in | | | | cubic feet per second. | | | | Typically, synonymous with | | | | streamflow or flow. | | +-------------------+------------------------------+---------------------------------------+ | .. _dblabel: | Land area where | `USGS Water Science Glossary`_ | | | precipitation runs off into | | | Drainage Basin | streams, rivers, lakes, and | | | | reservoirs. It is a land | | | | feature that can be | | | | identified by tracing a line | | | | along the highest elevations | | | | between two areas on a map, | | | | often a ridge. Large | | | | drainage basins, like the | | | | area that drains into the | | | | Mississippi River contain | | | | thousands of smaller drainage| | | | basins. Also called a | | | | "watershed." | | +-------------------+------------------------------+---------------------------------------+ | Exceedance | The probability a given flow | `Searcy (1959)`_ | | Probability | value will be equaled or | | | | exceeded during a given time | | | | period. | | +-------------------+------------------------------+---------------------------------------+ | Flow duration | A cumulative frequency curve | `Searcy (1959)`_ | | curve | showing the percent of time | | | | specified discharges were | | | | equaled or exceeded during a | | | | given period of record. | | +-------------------+------------------------------+---------------------------------------+ | Hydrograph | A plot of streamflow | `USGS Water Science School (2019)`_ | | | (discharge) versus time. | | +-------------------+------------------------------+---------------------------------------+ | .. _hulabel: | Hydrologic units and | `Jones and others (2022)`_ | | | associated n-digit (2-16) | | | Hydrologic Unit | hydrologic unit codes | | | | (HUC2-16s) belong to a widely| | | | used geographic framework | | | | for the conterminous United | | | | States (CONUS). Each unit | | | | defines a geographic area | | | | representing part or all of | | | | a surface drainage basin | | | | or a combination of drainage | | | | basins. For example, | | | | cataloging units (HUC8s) are | | | | each represented with unique | | | | eight-digit numeric | | | | identifiers, and they | | | | subdivide larger six-digit | | | | accounting units (HUC6s), | | | | four-digit subregions | | | | (HUC4s) and two-digit | | | | regions (HUC2s) into smaller | | | | areas designated by the U.S. | | | | Water Resources Council and | | | | the USGS's National Water | | | | Data Network. | | +-------------------+------------------------------+---------------------------------------+ | hyswap | HYdrologic Surface Water | `hyswap`_ | | | Analysis Package | | +-------------------+------------------------------+---------------------------------------+ | Metadata | Data that provides | | | | information about other data.| | +-------------------+------------------------------+---------------------------------------+ | NWIS | National Water Information | `USGS NWIS`_ | | | System | | +-------------------+------------------------------+---------------------------------------+ | Percentile | The value below which a | `USGS Water Science Glossary`_ | | | given percentage of | | | | observations in a group of | | | | observations fall. For | | | | example, the 20th percentile | | | | is the value below which 20 | | | | percent of the observations | | | | may be found. | | +-------------------+------------------------------+---------------------------------------+ | Raster | Pixed-based visualization | `Koehler (2004)`_ | | hydrograph | of, typically, streamflow | | | | data with years on the y-axis| | | | and days on the x-axis. | | +-------------------+------------------------------+---------------------------------------+ | Rating Curve | A drawn curve showing the | `USGS Water Science Glossary`_ | | | relation between gage height | | | | and discharge of a stream at | | | | a given gaging station. | | +-------------------+------------------------------+---------------------------------------+ | Recurrence | The average number of years | `USGS Water Science School (2018)`_ | | Interval | between floods of a certain | | | | size is the recurrence | | | | interval or return period. | | | | The actual number of years | | | | between floods of any given | | | | size varies a lot because of | | | | the naturally changing | | | | climate. | | +-------------------+------------------------------+---------------------------------------+ | Runoff | (1) That part of the | `USGS Water Science Glossary`_ | | | precipitation, snow melt, or | | | | irrigation water that | | | | appears in uncontrolled | | | | surface streams, rivers, | | | | drains or sewers. Runoff may | | | | be classified according to | | | | speed of appearance after | | | | rainfall or melting snow as | | | | direct runoff or base | | | | runoff, and according to | | | | source as surface runoff, | | | | storm interflow, or | | | | groundwater runoff. (2) The | | | | total discharge described in | | | | (1), above, during a | | | | specified period of time. | | | | (3) Also defined as the depth| | | | to which a drainage area | | | | would be covered if all of | | | | the runoff for a given period| | | | of time were uniformly | | | | distributed over it. | | +-------------------+------------------------------+---------------------------------------+ | Stage | The water level above some | `USGS Water Science Glossary`_ | | | arbitrary point in the river | | | | and is commonly measured in | | | | feet. | | +-------------------+------------------------------+---------------------------------------+ | Streamflow | The water discharge that | `USGS Water Science Glossary`_ | | | occurs in a natural channel. | | | | Typically, synonymous with | | | | discharge or flow. | | +-------------------+------------------------------+---------------------------------------+ | .. _wylabel: | A continuous 12-month period | `USGS Water Science Glossary`_ | | | selected to present data | | | Water Year | relative to hydrologic or | | | | meteorological phenomena | | | | during which a complete | | | | annual hydrologic cycle | | | | normally occurs. The water | | | | year used by the U.S. | | | | Geological Survey runs from | | | | October 1 through September | | | | 30, and is designated by the | | | | year in which it ends. | | +-------------------+------------------------------+---------------------------------------+ .. _Hammond et al. (2022): https://doi.org/10.1029/2022WR031930 .. _hyswap: https://doi-usgs.github.io/hyswap/index.html .. _Jones and others (2022): https://pubs.usgs.gov/tm/11/a3/ .. _USGS Water Science Glossary: https://www.usgs.gov/special-topics/water-science-school/science/water-science-glossary .. _USGS NWIS: https://waterdata.usgs.gov/nwis .. _Searcy (1959): https://doi.org/10.3133/wsp1542A .. _Koehler (2004): https://repository.arizona.edu/handle/10150/280516 .. _USGS Water Science School (2018): https://www.usgs.gov/special-topics/water-science-school/science/100-year-flood .. _USGS Water Science School (2019): https://www.usgs.gov/special-topics/water-science-school/science/streamflow-and-water-cycle .. _USGS Watershed Boundary Dataset: https://www.usgs.gov/national-hydrography/watershed-boundary-dataset