Mexico City has the best hotel shower ever. I am not one to spend a long time in the shower, but since I have long thick hair, efficient showers are of great importance to me when on travel. So-called eco-friendly showers are doing the exact opposite of their intentions in my case. You do not have to be a physicist to understand that the difference of spending 7-8 min under fast flowing water and close to half an hour in slow flowing water results in a larger volume of water transitioning from valuable clean water to waste water. For the record, I seldom spend more than 2-3 min in the shower.

Enough about personal details from my life. This excellent shower made me think about how this huge city, the largest on the western hemisphere, managed its water sources. After some quick research I was reminded that this old city is built upon a drained lake. Because of that, the entire city is subsiding at an incredible rate. Some places, like the cathedral, is sinking as much as 35-40 cm per year! I had to investigate further. Particularly because this is then all about using geodetic tools. And I am sucker for geodesy still after my many years working both nationally with geodesy and in the Global Geodetic Observing System, the International Association for Geodesy and others. I immediately contacted my geodesy friends and colleagues and asked for help.

The deformation of Mexico City is caused by ground water extraction, with some areas of the city subsiding at up to 2.5 cm/month (red). These preliminary results were presented at the InSARap Workshop at ESA’s ESRIN centre for Earth observation in December 2014. InSARap is a project under ESA’s Scientific Exploitation of Operational Missions (SEOM) programme. I have some news for you later, that will change this image substantially! Credit:  Copernicus data (2014)/ESA/DLR Microwave and Radar Institute–SEOM InSARap study

So far I have lined up a bunch of experts, both global and local ones, and the last half of this week at the Group on Earth Observation Ministerial Week in Mexico City, I will conduct some interviews on the subject. Stay tuned folks. You will learn the absolute latest about geodetic tools being applied on an amazing feature of a wonderful city.