Creating global monitoring of the load of hydraulic dams
Water resources monitoring, including surface and ground water, is a vital issue for governments and public institutions. Water resources are essential for society and economic activity (drinking water, irrigation, hydroelectricity, industry, flood control) and for natural and water ecosystems.
Generally, reservoirs stock information is collected and held by the local reservoir managers (public or private). Regional and national authorities might access this information with a certain latency, which depends on national water policies. Central authorities are then confronted to 2 issues: long latencies to retrieve water stock information and sparse or inexistent information about small reservoirs.
Stock-Water project holds a partnership initiative, open to new countries willing to participate, that proposes a global solution to monitor reservoirs stock volumes based on frequent satellite measurements. This solution is based on reservoirs area monitoring by imaging satellites (Sentinels 1&2). Volume information is then derived using digital elevation models (DEM) around reservoirs areas.
Figure 1. DEM Analysis to retrieve Elevation/Area/Volume relationships for each reservoir © ESRI/CNES
TERRITORIES FOR EXPERIMENTATION
StockWater partnership gather IRD collaborators in
- Burkina Faso
- Sentinel 1, Sentinel 2 for reservoirs imagery
- DEM Copernicus issued from satellite (TandemX)
- Elevation/Volume time series from some reservoirs to qualify volume estimations
RESULTS - FINAL PRODUCTS
Throughout the project lifetime, Stockwater provided several major outcomes:
- The proposed methods based on global DEM (30m resolution) provided similar quality results to those obtained from regional DEM (5m resolution), which validates the global approach.
- Estimation of Volume, Filling Rate and Water Areas of 110 reservoirs over six countries for 3 years
- Extended assessment of results over different territories, such as Spain, France, India and Brazil. Results over Andalusia and Occitania showed uncertainties lower than 8% for filling rates and 20 and 33% respectively for absolute volume estimations when compared to in situ records. Reservoirs in Brazil and India yielded worse filling rate uncertainties (like 27% in Brazil), but also, it should be considered that more in situ data inconsistencies were detected in such regions.
- An improved automation of the different processing components, chaining water surface estimation, reservoir bathymetry and the final time series calculation.
The detailed final report is available for download in the Resources section below.
- Results of 110 reservoirs for 3 years are available at sco-stockwater.org platform, allowing inter annual comparisons and regional water balance account.
- The bathymetry estimator from DEM is now released under open source license: github.com/CNES/dem4water
Stockwater might display inter-annual comparisons. In this example, volumes by radar measurements are shown for the years 2018 (red) , 2019 (yellow) and 2020 (blue) in Ramappa reservoir (Hyderabad, India). © SCO/CNES
Global monitoring requires improved accuracies for smaller water bodies, especially in terms of area estimation and DEM precision. An expansion of StockWater for such purpose would need to handle the development of new algorithms. On the other hand, estimation methods for extremely large reservoirs should also be revised.
- 03/03/2023: StockWater is available for water volumes and filling rates of dams
- 07/04/2022: Presentation of the Stock Water project and its progress at the 4th Quarterly Meeting of the SCO France on the theme "Water management and vulnerability of territories"