EFlowCalc - An open-source calculator of ecological stream flow characteristics in Python

EFlowCalc is an open-source calculator of ecological stream flow characteristics in Python. It is licensed under GNU GPL-3.0 (see licence file provided). EFlowCalc currently gives access to 17 of the 171 different ecologically relevant stream flow characteristics inventoried by Olden and Poff (2003). More characteristics will gradually be added to EFlowCalc. A key strength of EFlowCalc is the vectorisation of all calculations (using numpy, and therefore C code in the background) which makes for very efficient computation of the stream flow characteristics.

How to Install

EFlowCalc is available on PyPI, so you can simply use pip and the name of the package:

python -m pip install eflowcalc

You can also use pip and a link to the GitHub repository directly:

python -m pip install git+https://github.com/ThibHlln/eflowcalc.git

Alternatively, you can download the source code (i.e. the GitHub repository) and, from the downloaded directory itself, run the command:

python setup.py install

How to Use

A tutorial in the form of a Jupyter notebook is available to get started with the usage of EFlowCalc's API. The input file required for the tutorial is provided in the examples/ folder.

Stream Flow Characteristics Available

The stream flow characteristics currently available in EFlowCalc are as follows:

• Magnitude of flow events
  • MA26 - Variability of March flow
  • MA41 - Mean annual daily flow
  • ML17 - Base flow ratio
  • ML20 - Base flow 3
  • MH10 - Maximum October flow
• Frequency of flow events
  • FL2 - Variability in low pulse count
  • FH6 - Frequency of moderate floods
  • FH7 - Frequency of large floods
  • FH9 - Flood frequency
• Duration of flow events
  • DL9 - Variability in annual minimum of 30-day average flow
  • DH4 - Annual maximum of 30-day average flow
  • DH13 - Annual maximum of 30-day average flow normalised by median flow
  • DH16 - Variability in high-flow pulse count
• Timing of flow events
  • TA1 - Constancy by Colwell (1974)
  • TL1 - Timing of annual minimum flow
• Rate of change in flow events
  • RA2 - Variability in rise rate
  • RA7 - Rate of flow recession

These stream flow characteristics are amongst the 171 hydrological indices inventoried by Olden and Poff (2003). The computations implemented in EFlowCalc are partially inspired by the work of Henriksen et al. (2006), however EFlowCalc is neither endorsed by these authors nor by the U.S. Geological Survey.

Dependencies

EFlowCalc requires the popular Python packages numpy and pandas to be installed on the Python implementation where eflowcalc is installed.

Version History

• 0.0.1 [26 Oct 2018]: First version of EFlowCalc

Acknowledgment

This tool was developed with the financial support of Ireland's Environmental Protection Agency (Grant Number 2014-W-LS-5).