Environmental flow rates are a crucial benchmark for the sustainable use of water resources without compromising the preservation of natural ecosystems. Knowing their value everywhere is also a requirement established by Mexican law.
This requires, among other things, spatial interpolation techniques compatible with the nature of hydrological data (quantiles, expected values, basin averages, etc.).
A one-year stay at Irstea RiverLy allowed the doctoral candidate to acquire essential geostatistical skills for his work and to integrate them both into the scientific approach of his thesis and the tools developed at UAEM in this context.

On a worldwide scale, there has been an increasing desire to settle up environmental flow in national and regional policies and legislation. The aim is to conserve or restore the ecological health and functioning of rivers such that human demands can be met as well as related ecosystem biodiversity. Its benefits have been economically and ecologically seen by those countries that have already established it. In Mexico, that impact has been one of the main causes for the Mexican standard NMX-AA-159-SCFI-2012 that establishes the procedure for environmental flow assessment in hydrological basins.
The aim of the present research is to develop a hydro-informatics tool in order to assess the environmental flow in non-gauged basins. This is feasible due to the integration of interpolated images related to temperature, precipitation and run-off as well as other explicative variables such as: physical basin parameters, database of flow control dams, spatial relationship of endangered species richness or under special protection, land change use, hydrological alteration indices and climate changing indices. Once all the mentioned information has been recovered, a hierarchical cluster regionalization will be carried out in order to identify and classify regions with similar ecosystem-flow responses. In addition to that, several non-linear regressions will be developed for each cluster to assess the environmental flow in regions with lack of hydrological and climatological information. The proposed research methodology is compound by four stages. The first stage is assigned to integration and information processing. During the second stage, a hierarchical cluster analysis will be performed in order to identify areas with similar ecosystem-flow responses. On third stage, non-linear regression models will be calibrated for those regions where there is a considerable lack of information. Finally, a hydro-informatics tool will be developed in order to offer an efficient and friendly tool to water decision makers in Mexico.
The aim of the present Ph. D. Project is to develop a hydro-informatics tool to assess, in a semi-holistic approach, the environmental flow in non-gauged basins. The objectives are:
- 1. Integration and databases processing such as: physical basin parameters, run-off, climatological data, flow control dams, spatial relation of endangered species or under special protection and land change use;
- 2. Interpolation of climatological data such as: maximum temperature, minimum temperature and precipitation to assess climate change indices and check possible trends;
- 3. Regionalization of basins with similar ecosystem-flow responses;
- 4. Development of non-linear regressions for areas with noticeable lack of information;
- 5. Development of hydro-informatics tool to assess the environmental flow in non-gauged basins using the technical computing language MATLAB.

The PhD is based at UAEM. A one year stay at Irstea Lyon (1/8/2016-20/7/2017) was mostly devoted to understand and adapt to the Mexican data conditions the geostatistical tools for hydrological mapping developed over years by E. Leblois, E. Sauquet and co-authors. On 1/3/2017, the geostatistical developments were done.
The defense successfully happened in November 2018 in Toluca, Mex.

Financement

PhD Grant by Conacyt (Mexico) ; some extra fees for stay in Lyon by Irstea international affairs departement