The Sentinel 2 satellites have a Multi-Spectral Instrument (MSI) with 13 spectral bands that range from the visible range to the shortwave infrared (SWIR). Bands come in variable resolutions from 10 to 60 meter and their wavelenght is determined based on specific purposes.
Read MoreThe NDVI (Normalized Difference Vegetation Index) is a versatile vegetation index to evaluate the vegetation and dynamic of the vegetation coverage change. This index has been studied and evaluated with many satellites over the years, changing its calculus method in relation to the number and type of bands of the satellite. The following tutorial shows the NDVI calculus for Landsat 8 images using QGIS.
Read MoreIf you need hydrogeology bibliography that includes topics like modeling, groundwater quality and remediation, the options are scarce. In this article we will show 8 excellent and recent groundwater books and a summary about them.
The following books have been bought by the author in bookstores or through websites. They all are in English and are in no particular order.
Read MoreSentinel-2 carries an innovative wide swath high-resolution multispectral imager with 13 spectral bands for a new perspective of our land and vegetation. The mission is based on a constellation of two identical satellites in the same orbit, 180° apart for optimal coverage and data delivery. Together they cover all Earth’s land surfaces, large islands, inland and coastal waters every five days at the equator (source ESA).
This tutorial show the procedure to download especific granules from a ESA Sentinel 2 Image using the website: https://scihub.copernicus.eu/
Read MoreSentinel-2 carries an innovative wide swath high-resolution multispectral imager with 13 spectral bands for a new perspective of our land and vegetation. The mission is based on a constellation of two identical satellites in the same orbit, 180° apart for optimal coverage and data delivery. Together they cover all Earth’s land surfaces, large islands, inland and coastal waters every five days at the equator (source ESA).
This tutorial show the procedure to download images of ESA Sentinel 2 from the website: https://scihub.copernicus.eu/
Read MoreOne of the most common tasks when working with Geographic Information Systems (GIS) is the representation of points from a spreadsheet to a shapefile. Here, we will explain the steps to achieve this.
Read MoreEvaporation is accomplished by removing water from the chemical system. Water can be removed as an irreversible reactant with a negative reaction coefficient in the REACTION keyword input. This example uses this method; the REACTION data block is used to simulate concentration of rain water by approximately 20 fold by removing 95 percent of the water. The resulting solution contains only about 0.05 kg of water. In a subsequent simulation, the MIX keyword is used to generate a solution that has the same concentrations as the evaporated solution, but has a total of mass of water of approximately 1 kg.
Read MoreThe study of the environment, the understanding of the water cycle / atmospheric processes and the interaction with the aquatic and terrestrial ecosystems need advanced analysis tools. It is important to understand how the environment works and the potential impacts of our actions in the future. This goes further than a regulatory approach, we need a constant search and evolution of codes and models and this is where open source software has important advantages.
This article shows the most important open source software that can be used to make the different sections of an EIA.
Read MoreQGIS development in the past years has been impressive for an open source software. The current version is 2.18 Las Palmas. Each version is better than the previous one when it comes to functionalities, amount of tools, and bug fixing. In my opinion, for an intermediate QGIS user, the amount of new tools are bigger than the ability to learn them. Being up to date with the latest QGIS characteristics requires quite some time.
Read MoreThe following video is a useful tutorial that shows you how to plot terrain profiles using QGIS. In this example, we used two raster files: (1) one representing the elevation of the water table and (2) another representing the elevation of the terrain.
Read MoreThe spatial analysis world is dominated by two software: ArcGIS and QGIS. Both have been available for years and have a strong fanbase. The use of each one of these software generates a duality or polarization of the preferences and opinions about Geographic Information Systems tools (GIS). This article is not about showing the advantages of deficiencies of any of them, but to show the reasons why QGIS is a good option.
Read MoreWe have looked for different water resources free software, checked their documentation and analyzed their advantages and deficiencies to get this top 12.
Read MoreThis example demonstrates the capabilities of PHREEQC to perform a series of geochemical simulations, with the final simulations relying on results from previous simulations within the same run. The example investigates diagenetic reactions that may occur in zones where seawater mixes with carbonate ground water. This example is take from the Phreeqc documentation that can be found here:
https://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/html/final-72.html
Read MoreThis tutorial is about the hydrological modeling at basin scale using different hydrological process as:
The tutorial uses the Soil Moisture Accounting method and compares the results with observed flow measurement on the basin.
Read MoreWorking with graphical user interfases (GUIs) can be slow when one wants to do a severe trial-error runs on a groundwater flow model. Pumping test intepretation requires a lot of attemps in order to calibrate the steady and transient parameters as hydraulic conductivity, vertical anisotropy, specific storage and specific yield.
This tutorial show a procedure to generate the modflow files and run them by scripts in Python. The process allows to setup a generic model for a pumping test interpretation where the pumping rates, and observed head can come in separate files or arrays.
Read MorePHREEQC version 3 is a computer program written in the C and C++ programming languages that is designed to perform a wide variety of aqueous geochemical calculations. PHREEQC implements several types of aqueous models: two ion-association aqueous models (the Lawrence Livermore National Laboratory model and WATEQ4F), a Pitzer specific-ion-interaction aqueous model, and the SIT (Specific ion Interaction Theory) aqueous model. Using any of these aqueous models, PHREEQC has capabilities for (1) speciation and saturation-index calculations; (2) batch-reaction and one-dimensional (1D) transport calculations with reversible and irreversible reactions.
This tutorial shows how to calculate the solubility and relative thermodynamic stability of two minerals, gypsum and anhydrit as a function of temperature at 1 atm.
Read MoreMODFLOW is a versatil and applied computer code written in Fortran capable of modeling groundwater flow on steady and transient conditions. MODFLOW can simulate a diverse sort of groundwater flow management cases due to its packages and solvers. This tutorial shows the application of MODFLOW for the simulation of radial drains in a mine tailings facility. The simulation considers 16 drains of 60 m length over a simulation period of 1000 days.
Read MoreThis example calculates the distribution of aqueous species in seawater and the saturation state of seawater relative to a set of minerals. To demonstrate how to expand the model to new elements, uranium is added to the aqueous model defined by phreeqc.dat.
Read MorePHREEQC version 3 is a computer program written in the C and C++ programming languages that is designed to perform a wide variety of aqueous geochemical calculations. PHREEQC implements several types of aqueous models: two ion-association aqueous models (the Lawrence Livermore National Laboratory model and WATEQ4F), a Pitzer specific-ion-interaction aqueous model, and the SIT (Specific ion Interaction Theory) aqueous model. Using any of these aqueous models, PHREEQC has capabilities for (1) speciation and saturation-index calculations; (2) batch-reaction and one-dimensional (1D) transport calculations with reversible and irreversible reactions.
Read MoreNowadays, water resources management requires a better understanding of nature and a superior evaluation of the impacts caused by humans. We are concerned and focused on sustainability because we live on a planet with limited resources and changing environments. In some way, we know that the actual changes are results from past and present actions along with the effect of nature cycles.
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