Purpose

The Hydroscope interface enables visualising and extracting a set of descriptors of the river flow regime (including hydrological indices representative of low, mean and high flows). These descriptors are derived from time series of daily discharge.

Recommendation

Skills in both hydrology and statistical analysis are required before running Hydroscope. The user should also be able to convert data file into an appropriate input file format.

Precautions for use and limitations

Calculations are not allowed by Hydroscope
when the size of the sample is too small (less than four years of record).
In case the record period is ranging from 4
to 11 years, a warning message is displayed.

Values of the time series
have to be higher or equal to zero.

Calculations are performed with default options.
These options follow usual recommendations for statistical analysis applied
to hydrology. The user is advised to read the technical literature associated
with the hydrological indices, the stationarity tests and the statistical
inference to avoid misinterpretation of the results.

Annual minima and maxima are sampled considering
the calendar year as hydrological year. Seasonal sampling is currently
not possible with Hydroscope

Hydroscope basics

Available functionalities are listed in the menu located on the top of the webpage:

__1 - Data import
__

Importing the data is the first step. Hydroscope uses several input file formats to retrieve daily discharge data. The user specifies the appropriate format for the data to be read and then select a period of interest considered for the calculations.

Accepted data formats cover most standard data formats. Pre-processing may be necessary to conform to file formats available in Hydroscope.

If an error occurs, the user is notified with a message box. After the validation of the period of interest, the user can access the statistical tools for the hydrological analyses.

__2 - Hydrological
yearbook__

The hydrological yearbook enables visualising, comparing and extracting the main indices describing the overall hydrological regime – mean annual discharge, mean monthly discharge, quantiles extracted from the flow duration curves, etc. Some indices are calculated for each year and others are calculated over the whole period of interest.

__3 - High flows__

This analysis yields the following information:

- A characteristic flood hydrograph and an associated characteristics flood duration,

- A sample of annual maximum of d-day mean discharges (VCXd) . This sample is tested for stationarity (both trend and step-change test) and is used to fit a statistical distribution and compute the associated quantiles for a set of return periods T.

__4 - Low flows__

This analysis enables extracting a sample of annual minimum of d-day mean discharges (VCNd). This sample is tested for stationarity (both trend and step-change test), and is used to fit a statistical distribution and to compute the associated quantiles for a set of return periods T.

At each step the user can open contextual help by clicking on "?" to get guidance for the choices. Hydroscope enables creating output files with the main results and saving the graphs displayed on each page.

**Tip: Different sessions of Hydroscope
can be open in the browser to compare statistics from different gauging
stations.**

Hydroscope was developed within the HYCOS Follow-up project in cooperation between Irstea, CNR and MRC to facilitate visual analysis of daily discharge data with the financial support of AFD.

The interface was developed using the Shiny package from R-Studio (https://shiny.rstudio.com/) by Icare² (http://icare2.fr/). The scripts used for the statistical analyses were developed by Irstea.

R codes, graphics and HTML contents constitute the sole and exclusive property of Irstea. They are registered at Agence de Protection des Programme (https://www.app.asso.fr/en/welcome.html) under the number IDDN.FR.001.460014.000.S.C.2017.000.20700.

The sources are under licence GPL-3 (General Public Licence 3, https://www.gnu.org/licenses/).

For any additional information, please contact eric.sauquet[at]irstea.fr