Water Retention Index

WRI is a composite indicator developed to assess the capacity of the landscape to regulate and retain water passing through it. This indicator shows where there could be a deficit in the capacity of the landscape to retain water which, combined with rainfall extremes, could lead to higher flood risk or water scarcity. WRI is dimensionless and takes into account the role of interception by vegetation, the water-holding capacity of the soil, and the relative capacity of both the soil and the bedrock to allow percolation of water. The influence of soil sealing and slope gradient are additionally considered.