What is a Piper diagram for water chemistry analysis and how to create one?

In 1994, Arthur M. Piper, proposed an effective graphic procedure to segregate relevant analytical data to understand the sources of the dissolved constituents in water. This procedure was born under the statement that most natural waters contain cations and anions in chemical equilibrium. It is assumed that the most abundant cations are two “alkaline earths” calcium (Ca) and magnesium (Mg) and one “Alkali” sodium (Na). The most common anions are one “weak acid” bicarbonate (HCO3) and two “strong acids” sulphate (SO4) and chloride (Cl). Less common anion and cation-constituents are summed with the major three anions and cations as shown in the following table:

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Dynamic Simulation of Hillslope Landslide with openFoam - Tutorial

This tutorial shows the whole procedure to simulate a landslide of a hillslope from a initial condition of failure. The tutorial was done with the interFoam solver from openFoam on a non- Newtonian flow. The fluid has a variable kinematic viscosity (nu) based on the Bird-Carreau model. Failure scenario last only 6 seconds and results were recorded every 0.1 seconds. Final geometry and the landslide development were analyzed with paraView with predefined views (paraView states).

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Modeling and Analysis between 5 Newtonian Fluids in OpenFOAM - Tutorial

Computational fluid dynamics modeling with OpenFOAM could be challenging for water resources engineers since OpenFOAM models all types of fluids like water, air, heat and electromagnetism. On a normal hydrological software, it is implicit that the physical properties or the empiric formulation matches water on the liquid phase at temperatures around 20°C; however in a CDF program as OpenFOAM we have to define that the fluid we are working with is water and this increases the level of complexity on the model conceptualization and analysis.

But there is a interesting face of this complex fluid formulation in OpenFOAM: we can model any fluid, fluid type and turbulence condition; that means that we can model fluids like oil, alcohol, beer, or glycerine just with their property definition. In this tutorial we model and compare the behavior of 5 Newtonian fluids: beer, benzene, glycerine, olive oil and water. All fluids have been simulated on the same geometry and timeframe and all simulation output have been integrated in one paraView session for the comparative analysis of the fluid performance. Fluids were modeled with the interFOAM solver on turbulent conditions with the k-epsilon schema.

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Floating Object Stability Modeling with OpenFOAM - Tutorial

This tutorial is about a floating object stability simulation from a water surface oscillation (wave). The model was done with the interFoam solver that is a solver for two incompressible fluids, on isotermic conditions using a volume of control (VOF) phase-fraction interface approach. Turbulence was conceptualized on the model with the kEpsilon turbulence model. Simulation was done for 4 seconds with outputs every 0.05 seconds and runs in almost 5 minutes on OpenFOAM for Windows, better computation times are expected when run on Linux with paralleling computing.

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Electric Conductivity Analysis of a River Pathway using QGIS 3 and the Profile Tool Plugin

Electrical Conductivity (EC) has been used to analyze the content of dissolved salts in water. EC refers to the ability to transmit electricity (Ikeda et al. 1991). Pure water has low values of EC because the electricity is conducted by the ions in solution; therefore, the greater the concentration of ions in water, the greater the value of EC. This tutorial explains how to analyze the EC of a river using the Profile Tool plugin in QGIS 3.0.

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How to visualize time series in QGIS 3.0 with the Time Manager Plugin - Tutorial

Time series in hydrology can be analyzed to a) detect a trend due to another random hydrologic variable, b) develop and calibrate a model, c) predict future characteristics of a variable (Machiwal & Jha 2012). The application of time series analysis is diverse; for instance, it can be used to evaluate global trends of soil moisture (Dorigo et al. 2012), to analyze river discharges (Papa et al. 2012), to detect glacial lake outburst floods (Veh et al. 2018) or to detect rainfall patterns (Wang et al. 2016).

The visualization of the data variability over the time can be a useful tool to identify patterns or to compare the behavior of different samples. The use of software for Geographic Information Systems (GIS) allows to identify the location of the samples and to compile the information that the samples have. Open-source software like QGIS offers excellent tools to achieve this objective. This tutorial will explain how to use the Time Manager Plugin.

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Modeling Effluent Disposal Mixing Zone into the Ocean with OpenFOAM - Tutorial

A right assessment of the effluent mixing zone would require a baseline of sea currents, discharge flows, seawater and effluent density, bathymetry, waves, infraestructure geometry and a tool that can analyse the interaction of the mentioned factors. OpenFOAM is a numerical model for Computational Fluid Dynamics (CFD) modeling capable of modeling fluids with complex geometries, conditions and requirements; with OpenFOAM one can model compressible/uncompressible, single phase / multiphase, flows that mix, non-newtonian flows, etc. OpenFOAM comes with build-in tools for model construction and visualization, and there is Salome Platform for advanced mesh generation.

This tutorial show the entire procedure for the simulation of a effluent of 40 l/s into the ocean that has a current of 0.05 m/s. The model is on transient conditions, model simulation were done under uniform discharge rates, the development of the mixing zone was analyzed with paraView tools and a water chemistry component was introduced into the simulation with some Python scripts. 

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Comparison of IMERG Precipitation with Station Information with QGIS, Python and Pandas - Tutorial

There are tools for temporal data analysis like Python, IPython and Jupyter; there are tools for spatial data analysis like QGIS. But, are there tools for spatio-temporal analysis? Unfortunately no, but there are good approaches to manage spatial data in Jupyter or to run IPython in QGIS3. These approaches aren't a complete ansqwe to the current demands of big data processing in few computational time with simple scripts, but by sure it will help to shape better solutions.

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OpenFOAM Model Local Mesh Refinement with Salome and Python3 - Tutorial

Discretization is the “art” of transforming a continuous media as nature into discrete parts; for numerical models the spatial and temporal discretization have become a key issue in assuring model efficiency, output precision and the overall quality of the modeling work. Flow models are constructed to represent an specific requirement on the surface water/ groundwater flow regime (local scale), however, the model has to represent first the overall flow regimen (global scale). On the general model areas, an efficient spatial discretization criteria rules to keep the mesh elements as big as possible, meanwhile, in the areas of interest the model should be discretized into the smallest parts.

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Direct NASA IMERG precipitation images download in QGIS3 with Python

The new version of QGIS is QGIS3 and it runs with Python 3 which introduces some change on the interaction with webservers with package “requests”. For those that are new to the IMERG images, those are some kind of the new TRMM images with precipitation estimation from multiple passive microwave (PMW) sensors on various precipitation-relevant satellites starting in March 2014. The IMERG images have a pixel resolution of 0.1 degrees and a temporal scale of 30 minutes; on the current panorama of precipitation estimates based on satellite-gauge, the IMERG data product with the highest spatial and temporal resolution available over the last 4 years.

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Massive Operations on Rasters with QGIS3 and Python - Tutorial

There are new available tools and resources to understand climate change, land use dynamics, water cycle and other parts of our physical environment. Many spatial data come on raster format and are available on web servers, those servers have a image register every year, every month, every day, hour, half hour or minute. If we want to assess a physical phenomena we have to be able to analyze large set of data.

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Object / fluid interaction modelling with OpenFOAM - Submarine Case - Tutorial

This tutorial will apply OpenFOAM to simulate the flow effect on submerged object using the simpleFoam solver and the k-epsilon turbulence schema. The tutorial develops the case of a submarine model against a flow current; the velocity and pressure applied on the submarine will be analyzed on the model results and flow paths will be plotted to see the main patterns around the submarine. Model output visualization is performed on Paraview that allows the representation of velocity and pressure vectors over the submarine.

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Energy Dissipator Modelling in Open Channels with OpenFOAM - Tutorial

This tutorial will demonstrate the modelling configuration to simulate a power dissipator in an open channel. The dissipator design is proposed on the Stormwater Drainage Manual from the Drainage Services Department of Hong Kong and  OpenFOAM will be used for the simulation with the interFoam solver since two immiscible and isothermal fluids are involved (water and air). The main variable of interest on the dissipator simulation is flow velocity to assess the efficiency of the dissipator.

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How to download and use the LocClim software to estimate climate - Tutorial

LocClim is a software developed by the Agrometeorology Group of the Food and Agriculture Organization of the United Nations. The software provides an estimate of climatic conditions at different location regardless of the availability of observations. This software is of great importance if you want to know the climatic conditions of certain location and you do not have available observation points. It is possible to modify the stations that provide the data, so you can control the accuracy of the estimates. This tutorial demonstrates how to download the New LocClim software, how to find a location and how to export the resulting data.

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Downloading and preprocessing Sentinel 2 images using the Semi-Classification Plugin in QGIS 3.0

Sentinel-2 carries an innovative wide swath high-resolution multispectral imager with 13 spectral bands (443–2190 nm) (European Space Agency). Sentinel images have a swath width of 290 km and a spatial resolution of 10 m (four visible and near-infrared bands), 20 m (six red edge and shortwave infrared bands) and 60 m (three atmospheric correction bands) (Satellite Imaging Coorporation).The images are very powerful and are of great relevance for land and water management because analyses can be done from the spectral bands, natural color and false color image can be visualized and spectral indices can be obtained. Therefore, downloading them for free is an incredible opportunity for scientists and analysts to meet their goals. This tutorial demonstrates how to download and preprocess Sentinel 2 images using the Semi-Classification Plugin in QGIS 3.0. In addition, how to install the plugin is explained.

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How to insert a background image in ModelMuse - Tutorial

It is very common that before we start doing the modelling in Model Muse, we first begin with a geographic information system like QGiS where we can see our data and define the information we are going to import into ModelMuse. We usually use background images for a better understanding of where we are located, what we are seeing and how this terrain may be affecting our results. 
It is also useful to have a background image in ModelMuse as we do in QGIS in order to ease the analysis of the simulation results in the software. In this tutorial we will show you how to do this in a very simple way so you can apply it in future models.

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How to model a contaminant plume with ModelMuse and MT3DMS - Tutorial

MT3DMS Is a modular three dimensional transport model that can be coupled with Modflow to simulate the concentration changes of miscible contaminants in groundwater considering different processes like advection, dispersion, diffusion and some chemical reactions.

By studying how the contaminants behave in groundwater we can determine influence areas and use this information in prevention plans to reduce contamination in order to achieve a sustainable management of aquifers.

In this tutorial we will show how to set up a MT3DMS in simple ModelMuse model in order to evaluate the degradation of the contaminant coming from a source.

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Labelling and Clipping using Hydrologic Information of a Basin in QGIS 3.0 - Tutorial

Presenting Geographic Information Systems (GIS) is of great importance to transmit the correct ideas of the analyzed information. QGIS 3.0 is a powerful software to design and present maps. GIS can contain diverse and vast information; however, the analyst should decide what to present and how to present it. Therefore, labelling is a skill that must be developed when creating maps. This tutorial shows how to clip features to the shape of the study area and how to label the features of interest. The study area is a basin within the state of Tlaxcala, Mexico and it has a channel network shapefile and points with the name of the channel network features. The explanation includes how to create an expression to label the features using conditionals and how to change the style of the labels using QGIS 3.0.

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Particle Tracking Simulation with Model Muse and Modpath - Tutorial

MODPATH is a particle tracking post-processing package that computes and displays three-dimensional pathlines based on output from MODFLOW. These pathlines help us to see the expected transport trajectories coming from a specific contaminant source. In addition, we can also use this package to obtain the time that these pathlines will take to reach a particular point. 

In this tutorial, we will show how to set up MODPATH to see the movement of particles over time coming from a  contaminant source and how these can be influenced by factors like the presence of low permeability areas.

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How to obtain a Basin, Channel Network and Flow Accumulation from a Digital Elevation Model with no sinks in SAGA GIS and QGIS 2.18 – Tutorial

A basin is defined as a topographic region in which all water drains to a common area. Identifying basins within a study area can be beneficial for land and water management because priority areas can be defined and the hydrology of the area can be visualized. Delimiting a basin can be done by using Geographic Information Systems such as QGIS and SAGA GIS. To do so, a Digital Elevation Model (DEM) is required since the drainage network is determined by the elevation and slope of the terrain. This tutorial demonstrates how to reproject a DEM raster in QGIS, how to fill the sinks of a DEM, to calculate flow accumulation, to obtain the channel network and the basin limits with SAGA GIS based on the DEM using the Upslope Area interactive tool.

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