WaPOR, remote sensing for water productivity

Introduction

WaPOR, FAO’s portal to monitor Water Productivity through Open access of Remotely sensed derived data, monitors and reports on agriculture water productivity over Africa and the Near East.

It provides open access to the water productivity database and its thousands of underlying map layers. It allows for direct data queries, time series analyses, area statistics and data download of key variables associated to water and land productivity assessments.

The portal’s services are directly accessible through dedicated FAO WaPOR APIs, which are being gradually published and documented through the FAO API site.

Water productivity assessments and other computation–intensive calculations are powered by Google Earth Engine.

Water and land productivity is assessed in a different way for the three spatial levels:

On level I (continental level - 250 m ground resolution), water productivity is monitored in terms of biomass production per hectare per cubic meter of water consumed. A distinction is made between irrigated and rainfed agriculture. Land and water productivity are calculated on pixel basis, which can be aggregated to country or river basin level.

On level II (national and sub-national level - 100 m ground resolution), land and water productivity is monitored for a selected set of countries and river basins while distinguishing several main crops under irrigated or rainfed agriculture. Land productivity is expressed in terms of yield (kg/ha), water productivity is calculated as production per volume of water (kg/m³).  Water used for agricultural production is expressed in actual evapotranspiration, where a distinction is made between evapotranspiration originating from precipitation (‘green’ water) and incremental evaporation originating from irrigation (‘blue’ water).

On level III (irrigation scheme and sub-basin - 30 m ground resolution), land and water productivity is monitored for a selected set of irrigation schemes to assess the functioning of the irrigation system and to propose improvements of these systems. On this level land and water productivity is calculated similarly to level II. In addition, economic water productivity for multiple uses of water is assessed in terms of economic return per amount of irrigation water used. Indeed, water productivity plays a central role in the performance assessment of irrigation which is the basis of irrigation modernization. After modernization of an irrigation scheme, the water services provided to all water users should be more reliable, more cost effective, more adapted to increased climatic variability due to climate change and more environmentally friendly.

On spatial level III, special emphasis is given to the multiple uses of water services (MUS) in agriculture. MUS can provide the more vulnerable water users with low cost services for domestic water, water for homesteads, water for livestock, habitats for fish and other aquatic resources and rural enterprise water supplies. The multiple uses of water services often increases the economic productivity of water use in irrigation schemes. Within multiple uses of water services, gender relations are of main interest.