As the world marks World Water Day on Monday 22 March the Food and Agriculture Organisation of the United Nations warns that just 30 years from now there will be a dire need for the precious resource

In 2050, our planet will need to provide food for an estimated 9 to 10 billion people. In order to produce anything like that figure, we’re going to need a lot of water.

Achieving food security in the future while using water resources in a sustainable manner is a major challenge for this and for next generations. The big question is:  how can we increase water productivity so that we can grow more crops per drop?

Well, technology could be the answer. FAO’s portal to monitor  Water Productivity through Open-access of Remotely sensed derived data (WaPOR) uses satellite data to help countries monitor agricultural water productivity, identify water productivity gaps and find solutions. By increasing water use efficiency, we increase the amount of crops grown with the same amount of water and can provide food for a larger population.

What is water accounting?

Everyone needs access to water for agriculture, but it’s a finite resource and as our population increases, there’s not always enough to go around. As an example, the Nile River is one of the vastest basins, extending within and across the borders of 11 countries. For these countries, which include Egypt all the way to Burundi and Tanzania, the Nile is the main source of water.  All these countries have economies that are centred around agriculture and that means water access is competitive.

In order to cope with that pressure on water resources, it is important to understand and account for the water that is available. Water accounting shows where and how much water there is and who can access it.

How does it work?

Thanks to new developments in earth observation technology, we can monitor water management data using satellite remote sensing.

Satellites are able to measure and quantify evapotranspiration, the process that includes both evaporation of water from the soil and water bodies, as well as transpiration from plants. By measuring the evapotranspiration of an agricultural plot, we can understand how much water the crops have used in their development from seed to harvest. Several satellites, from both the National Aeronautics and Space Administration of the  USA (NASA) and the European Union Earth Observation programme (Copernicus), provide free global data on evapotranspiration. FAO is using this information to develop a publicly accessible, near real-time database that monitors agricultural water productivity.

Who benefits from the information?

Anyone needing information on using water more efficiently!

By measuring evapotranspiration water productivity can be improved by using the appropriate farming practices. This data, which is available on FAO’s WaPOR portal, assists countries in monitoring water productivity, identifying water productivity gaps, proposing solutions to reduce these gaps and contributing to a sustainable increase of agricultural production. Government agencies can use it to monitor the state of their natural resources and promote their efficient use. Local partners can translate this water productivity data from satellites into practical solutions to improve water productivity.

For example FAO, in partnership with the International Water management Institute (IWMI), carried out an assessment in 2018 on the Koga reservoir irrigation scheme in Ethiopia. Based on the data, the team designed and implemented activities with the aim of improving water productivity in irrigation, which included reducing water irrigated to the crop during the growing season when the data showed water in the ground was plentiful.

Farmers can use WaPOR to evaluate how productively they use water on their farm and monitor the effect of improved water management over time.  It can even be used to develop apps that can be run on smart phones and provide locally relevant information. For example, in Egypt, the International Water Management Institute in partnership with the Soil, Water and Environmental institute and FAO have developed a mobile application for farmers, providing information of local conditions of water and vegetation and helping farmers ensure that they grow the right crops in the appropriate climatic conditions.

Johannes Phoku is a subsistence and small scale commercial farmer in Motsane in Sekhukhune. He says the COVID-19 lockdown has had a major impact on his livelihood and is worried about the future. Photo: Lucas Ledwaba/Mukurukuru Media

Let’s put this into context…

Rwanda suffers from localised water scarcity or an excess of demand over available supply. In fact, the capital Kigali often experiences water shortages. To change this, it is important to understand and manage the quantity of water used from the rivers that Kigali depends on for its water supply. WaPOR data can help provide the answer.  

Prime Ngabonziza, the Director General of Rwanda Water Resources Board, explains: “In Rwanda, the level of water scarcity is projected to increase in the future as the country continues to develop economically and as its population grows. Maintaining accurate information and data on the amount of water used and the purposes of its use are important for effective water resources management,” he says.

The FAO project “Knowing Water Better” (KnoWat) aims to build local capacities for water accounting, and train technical staff on data collection and use. In Rwanda, the project is reviewing water management and allocation of the Yanze River, one of the main water sources for Kigali as well as a vital source of water for small-scale farmers, pastoralists and fisherfolk. WaPOR data will be used to update water balance studies through a detailed assessment of evapotranspiration, precipitation, land cover, biomass production and water productivity. This will then inform decisions on sustainable water governance and management, so that users can get water they need, when they need it.

Our world is changing. Our population is growing and the way we use water is becoming ever more important. More people than ever are depending on the same supply. Technology and data are key to solving this problem, creating a sustainable, modern agricultural sector fit for the future.

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