April 07, 2017

How to Download Specific Granules from ESA Sentinel 2 Images

April 07, 2017/ Saul Montoya

Sentinel-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/

April 07, 2017

How to Download ESA Sentinel 2 Satellite Images

April 07, 2017/ Saul Montoya

This tutorial show the procedure to download images of ESA Sentinel 2 from the website: https://scihub.copernicus.eu/

April 06, 2017

Evaporation and Homogeneous Redox Reactions Simulation with Phreeqc

April 06, 2017/ Saul Montoya

Evaporation 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.

April 04, 2017

Geochemical Simulation Tutorial of Water Mixing with Phreeqc

April 04, 2017/ Saul Montoya

This 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

April 04, 2017

Hydrological Modeling at Basin Scale with HEC HMS Tutorial

April 04, 2017/ Saul Montoya

This tutorial is about the hydrological modeling at basin scale using different hydrological process as:

Evapotranspiration
Baseflow
Interception
Surface accumulation

The tutorial uses the Soil Moisture Accounting method and compares the results with observed flow measurement on the basin.

April 02, 2017

How to Pythonify (modify and run with Python) a Pumping Test Model in MODFLOW

April 02, 2017/ Saul Montoya

Working 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.

March 31, 2017

Solubility and Thermodynamic Stability of Gypsum and Anhydrite with Water with Phreeqc

March 31, 2017/ Saul Montoya

PHREEQC 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.

March 29, 2017

Simulation of Radial Drains for Tailings Drainage with MODFLOW Tutorial

March 29, 2017/ Saul Montoya

MODFLOW 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.

March 28, 2017

Aqueous species in water speciation calculation with Phreeqc tutorial

March 28, 2017/ Saul Montoya

This 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.