ORGANIZED BY UNESCO Project “Biosphere and Heritage of Lake Chad” (BIOPALT)

UNESCO Intergovernmental Hydrological Programme (IHP)

International Initiative on Water Quality (IIWQ)

WATER QUALITY MONITORING USING

SATELLITE EARTH OBSERVATION: In collaboration with Lake Chad Basin Commission (LCBC) UNESCO WATER QUALITY PORTAL FOR THE LAKE CHAD BASIN

ONLINE TRAINING | 23 - 24 March 2021 With support for the project BIOPALT

With scientific and technical expertise of

Context The UNESCO Project “Biosphere and Heritage of Lake Chad” (BIOPALT), aims to strengthen the capacities of the member states of the Lake Chad Basin Commission (LCBC) to safeguard and sustainably manage the hydrological, biological and cultural resources of the Lake Chad Basin, in order to contribute to poverty reduction and promote peace. It is implemented in collaboration with the LCBC in five countries of the Lake Chad Basin (Cameroon, Niger, Nigeria and Central African Republic) for a period of four years, with financing from the African Development Bank (AfDB).

Within this intersectoral UNESCO Project BIOPALT, an activity focuses on the operational application of satellite- based water quality monitoring in the Lake Chad Basin through the UNESCO Water Quality Portal, developed under the International Initiative on Water Quality (IIWQ) of UNESCO’s Intergovernmental Hydrological Programme (IHP). In this context, the UNESCO Water Quality Portal for the Lake Chad Basin, which combines satellite Earth Observation (EO) and in-situ water quality monitoring data, has been developed for surface water quality monitoring of the Lake Chad and its main tributaries. The UNESCO Water Quality Portal is developed with scientific and technical expertise of: French National Research Institute for Sustainable Development (IRD); French National Centre for Space Studies (CNES); French Institute for Biodiversity (OFB); French National Research Institute for Agriculture, Alimentation and Environment (INRAE); French Scientific Research Institute (CNRS); and Magellium. Experts from the LCBC have contributed to collecting and analysing in-situ water quality measurements.

The UNESCO Water Quality Portal is an innovative scientific tool, which enables the LCBC and the Member States, sharing this transboundary basin, to monitor the water and natural resources of the basin and to support the sustainable management of these resources.

The activity aims to strengthen the technical and human capacity of the LCBC on water quality monitoring. To this end, a training workshop on water quality monitoring using satellite EO and the use of the UNESCO Water Quality Portal is taking place from 23 to 24 March 2021. The training is intended for professionals of the LCBC, as well as for water professionals, environment and health specialists, decision-makers, researchers and other stakeholders from the five member countries sharing the Lake Chad Basin: Cameroon, Central African Republic, Chad, Niger, and Nigeria.

Objectives The training will enable participants to: - acquire theoretical knowledge on the innovative approach to monitoring freshwater quality using Earth observation satellites ; - acquire practical skills for using the UNESCO Water Quality Portal and to interpret the data and products made available through the Portal; - manipulate the Portal products and provide a synthetic analysis of the spatial and temporal dynamics of the different water quality parameters measured to support decision making on the management of water and water-related ecosystems. The overall objectives of the training are to: - promote innovative approaches to freshwater monitoring to address the lack of data and information on water quality at local, national, regional and global levels and to foster open access data sharing. - facilitate science-based policy development and management priorities for the protection of water quality and ecosystems, for the sustainable management of water resources, and for the implementation of the Sustainable Development Goals (SDGs), including SDG 6: Clean Water and Sanitation, and SDG 15: Ecosystems and Biodiversity. Programme Day 1: Tuesday, 23 March 2021 09:00 – 09:40 Opening session Opening speeches • Alio Abdoulaye, Technical Director a.i., Lake Chad Basin Commission • Noeline Raondry Rakotoarisoa, Chief of the Section on Biosphere Network and Capacity Building, Division of Ecological and Earth Sciences, UNESCO Presentation on the UNESCO World Water Quality Portal: from the demonstration phase to operational applications Ms Sarantuyaa Zandaryaa, Programme Specialist, International Initiative on Water Quality, Division of Water Sciences – Intergovernmental Hydrological Programme, UNESCO 09:40 – 11:00 Session 1: Introduction to the monitoring of water resources using remote sensing The monitoring of water quality is essential for the definition of environmental policies as well as for the assessment of the impact of these policies. The session will begin with a broad review of the application of Earth observation satellites for water cycle assessment. A short introduction on the conventional techniques used for water quality monitoring in catchments will be given. The lack of robust monitoring networks across the world is leading the stakeholders to consider alternative techniques such as remote sensing data that make possible to monitor multiple components of the water hydrological cycle. As an introduction to the techniques used for water monitoring using satellite images and for the elaboration of the UNESCO Water Quality Portal for the Chad Lake Basin, basic concepts and examples of results of monitoring water level and water temperature from space will be presented. Earth and water resources observation using satellite data - general presentation Alice Andral, French National Centre for Space Studies (CNES) General objectives of water quality monitoring of lakes and rivers; types and sources of pollutants; main protocols for conventional water quality measurements Jean-Michel Martinez, French National Research Institute for Sustainable Development (IRD) Introduction to spatial altimetry for monitoring water level over lake and rivers Alice Andral, CNES Introduction to the estimation of water surface temperature from satellite images Thierry Tormos, French Institute for Biodiversity (OFB) A short break 11:00 – 12:00 Session 2: Introduction to water quality monitoring by optical and infrared remote sensing In this session, the main concepts related to the monitoring of water quality using satellite images will be presented, in particular: a presentation of the water quality parameters that can be monitored from space; light absorption and scattering processes by water-optically active components; calculation of the remote sensing reflectance, atmospheric corrections and skylight reflection at the water surface. Finally, methods allowing the calibration and validation of the remote sensing products will be discussed. Review of the main concepts concerning the optical properties of water, the relationship between water quality and water color, and presentation of water quality parameters detectable by remote sensing Guillaume Morin, OFB Revision of the processing techniques used to produce water quality parameter maps for the Lake Chad portal: characteristics of the sensors and satellites used, atmospheric and skylight reflection corrections, presentation of the algorithms used to quantify turbidity and suspended matter concentration, eutrophication (Chlorophyll-a and HAB), dissolved organic matter Tristan Harmel, French Scientific Research Institute (CNRS) Calibration and validation methods for water quality parameters obtained from satellite images and examples of validation from the literature Tristan Harmel, CNRS 12:00 – 12:45 Session 3: Interpretation of satellite images and application examples In this session, examples of the use of satellite images for environmental studies will be presented to illustrate the new possibilities linked to the use of remote sensing data for the observation of the environment. Through examples, the emphasis will be placed on the characteristics of satellite products (spatial resolution, temporal frequency, spectral resolution, etc.) and how users should consider these specifications when analyzing the results and understanding their representativeness. Basic concepts for the interpretation of a water quality map obtained from satellite images, analysis of the impact of spatial resolution, acquisition frequency, temporal coverage and cloud cover. Presentation of some remote sensing-based applications on the detection of environmental changes in lakes and rivers around the world Jean-Michel Martinez, IRD

Day 2: Wednesday, 24 March 2021 09:00 – 10:45 Session 4: Presentation of the satellite-based UNESCO World Water Quality Portal for Lake Chad Basin This session will focus on the new UNESCO Water Quality Portal for the operational monitoring of Lake Chad Basin. It will include presentations: on the water quality parameters available on the portal; the validation results in comparison with the available in-situ measurements; and some examples of use. Presentation of the basin water quality parameters provided by the UNESCO portal Tristan Harmel, CNRS Validation of the portal products based on the data collected by the CBLT during the preparation phase of the portal and on historical time series: presentation of the data collected by the CBLT and analysis of the results of comparison between field and satellite data Hamit Abderamane, LCBC / Jean-Michel Martinez, IRD Data visualization and handling using the portal: viewing maps and time series, navigating between the different information layers, downloading data, metadata Remi Jugier, Magellium A short break 10:45 – 12:15 Session 5: Practical exercises and interactive discussions on the first results obtained from the assessment of the data provided by the UNESCO Water Quality Portal In this session, the participants will be invited to use the UNESCO World Water Quality Portal in order to visualize the Lake Chad water quality data on their own computers. This exercise, including data visualization and downloading, will be proposed and supervised remotely by the training supervisors. The analysis of the Portal’s data makes possible to retrieve seasonal and inter-annual variations of the water quality parameters retrieved from space. A review of the water quality parameter variations, based on the Portal’s data, including comparisons with past observations will be presented and discussed with the participants before engaging in an interactive discussion. Practical exercises: the participants will manipulate the portal on their own computer and carry out a series of tasks, defined in advance, to test each stage of consultation of the site The training facilitators will intervene and will be available to help the participants and respond to questions. Presentation and discussion of the firsts results obtained from the analysis of the remote sensing- derived products available on the portal: monitoring of seasonal and inter-annual variability of the water quality parameters monitored and comparison with the measurements available in the literature on the Lake Chad Basin Jean-Michel Martinez, IRD Discussions between participants and training speakers 12:15 – 12:30 Closing Feedback from the participants Closing remarks

Contact UNESCO Secretariat Sarantuyaa Zandaryaa (s.zandaryaa(at)unesco.org) Division of Water Sciences – Intergovernmental Hydrological Programme (IHP), International Initiative on Water Quality Bandiougou Diawara (b.diawara(at)unesco.org) UNESCO Project BIOPALT Djibrilla Mohamadou (d.mohamadou(at)unesco.org) UNESCO Office for Central Africa in Yaoundé Lake Chad Basin Commission (LCBC) Hamit Abderamane (a.hamit (at) cblt.org), Water Quality Expert