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Risks: water and soil
Improve the quantity and quality of water and soil
The ACMG analyzes the risks associated with climate change and their impacts on soils and surface or deep water. The technical service produces land use maps at the watershed scale by processing satellite images (radar and optical), implements water level monitoring observations, participates in work on recharge water tables and soil erosion.
Observe impacts via satellite
Knowing the land use of a watershed makes it possible to target areas at risk of runoff, to rethink the vegetative covers of the basins, to improve water retention.
In order to be able to observe the soils during intense climatic periods, the ACMG has innovated and today uses the RADAR satellite to map four land uses within the watersheds: active vegetation, bare soils, vines, woods.
Sensitivity of soils to erosion in the Labourdasse watershed
Example of use of cards:
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Development of the edges of watercourses
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Quantification of bare soils from 2015 to 2020 within watersheds
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Change in the proportion of active vegetation over the year, month by month
Measure water levels
" Réagir puis agir "
In order to develop watersheds, manage low water levels and warn about the risk of flooding, ACMG is developing and testing, within the framework of the European projects RiskAquaSoil and ClimAlert, a new station transmitting information from sensors every 12 minutes. water level supplemented with meteorological parameters.
The ClimAlert program makes the data available for the Moyen Garonne on the Aqualis.fr platform.
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Water level station (Sérac - 47)
Connected to meteorological stations and soil moisture probes, these sensors make it possible to relate climatic hazards, the soil's water retention capacity and the state of the watercourse. Linked together, this information makes it possible to alert in real time and then to think about solutions adapted to the specificities of the basin.
Flood mapping
" Anticipate climatic events "
The ACMG maps the extent of flooding from satellite radar images in order to meet the needs of waterway managers, local communities, emergency services and municipalities in their implementation of adaptation strategies. and risk management.
This service offers the possibility:
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To observe the extent of the impacts over a large area in order to respond as quickly as possible to the needs of emergency services as well as to the various managers in the territory.
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To observe the evolution of the flooded area day after day according to the availability of satellite images (map with in yellow and in red according to evolution between the 27th, 02nd and 03rd).
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To establish the history of flooding over time: radar data available since 2015, optical data since 1985-1990 on certain areas.
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To understand the origin of the phenomena and to model the risks and future impacts if necessary by linking for example the extent of the floods with the occupation of the watersheds, the quantity of fallen water, the water retention capacities of the soils, etc.
This mapping service can be combined with the early warning service (flood warning) set up as part of the Interreg ClimAlert project within the rivers of rural areas of Lot et Garonne and Dordogne.
Flood of the Garonne river in February 2021