... | ... | @@ -8,7 +8,9 @@ including the water-quality method Weighted Regressions on Time, Discharge, and |
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Evaluating long-term changes in river conditions (water quality and discharge) is an important use of hydrologic data. To carry out such evaluations, the hydrologist needs tools to facilitate several key steps in the process: acquiring the data records from a variety of sources, structuring it in ways that facilitate the analysis, routines that will process the data to extract information about changes that may be happening, and graphical techniques that can display findings about change. A pair of tightly linked R packages, called `dataRetrieval` and `EGRET` (Exploration and Graphics for RivEr Trends), have been developed for carrying out each of these steps in an integrated manner. They are designed to accept easily data from three sources: U.S. Geological Survey hydrologic data, Water Quality Portal Data (currently including U.S. Environmental Protection Agency (EPA) STORET data, and USDA STEWARDS data), and user-supplied flat files. The `dataRetrieval` package not only serves as a "front end" to the `EGRET` package, it can also be used to easily download many types of hydrologic data and organize it in ways that facilitate many other hydrologic applications. The `EGRET` package has components oriented towards the description of long-term changes in streamflow statistics (high flow, average flow, and low flow) as well as changes in water quality. For the water-quality analysis, it uses Weighted Regressions on Time, Discharge and Season (WRTDS) to describe long-term trends in both concentration and flux. `EGRET` also creates a wide range of graphical presentations of the water-quality data and of the WRTDS results. This report serves as a user guide to these two R packages, providing detailed guidance on installation and use of the software, documentation of the analysis methods used, as well as guidance on some of the kinds of questions and approaches that the software can facilitate.
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The link for the official USGS publication user guide is here:
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[http://dx.doi.org/10.3133/tm4A10](http://dx.doi.org/10.3133/tm4A10)*
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*Awaiting final edits, expected to be published very soon
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Package Installation
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