- Nick Cuba
Interactive Map: Mariana Dam Disaster
Updated: Sep 27, 2019
On November 5, 2015 an iron ore tailings dam failed in Mariana, Minas Gerais, Brazil. The catastrophic flooding that resulted downstream resulted in the deaths of 19 people and severe environmental devastation.
False-color composites are images that assign reflectance values to the (screen-visible) Red, Green, and Blue that come from areas of the spectrum that are NOT Red, Green, and Blue. Here, Red on screen does show red band reflectance, but Green shows near-infrared reflectance, and Blue shows short-wave infrared reflectance.
Photosynthetically productive vegetation strongly reflects near-infrared reflectance, so the bright green areas here show high vegetation density. Brown shows fallow fields, and purple shows bare soil or built-up areas.
You can find the interactive map HERE. Clicking the "rainbow" layer button in the top right triggers a sliding feature in the map that allows you to compare Landsat images from just before, and just after the collapse. It also opens up a panel where you can toggle on/off a red feature that shows the affected area immediately downstream.
A paper by Aires et al. in the journal Land Use Policy provides a detailed description of the effects experienced downstream from the dam collapse and use perform multi-criteria evaluation in Idrisi software (developed at Clark University) to investigate potential local sites for the disposal of tailings.