VIRG: Vegetation interception of rainfall using nature’s gamma radiation

All drinking water in Denmark originates from our groundwater resources. Precise knowledge of how much new groundwater is generated each year and the variation over the season is necessary to ensure sustainable groundwater usage by maintaining sufficient water for groundwater dependent ecosystems and streamflow. The water budget describing the partitioning of rain into evapotranspiration and groundwater recharge depends on land cover. Changing the land cover, from agriculture to forest, is increasingly used as a water management practice to improve the water quality, for climate mitigation, and to ensure biodiversity. The significance of evaporation of rain intercepted by the forest canopy (known as interception loss) is well established and has been widely examined during the last decades. To date, the temporal interception loss of other vegetation has not been measured as the state-of-the-art measurement techniques are inappropriate for shorter plants. For hydrological applications, gamma-ray spectrometry (GRS) is a novel measurement technique. Using custom-made spectrometers and a unique measurement design, this cutting-edge experiment will explore the use of natural gamma radiation to quantify the temporal interception loss at an agricultural field.