Unsaturated Zone

About the Technical Committee

The unsaturated (or vadose) zone is critical in the partitioning of incident precipitation into run-off, storage, recharge, or evaporation. It is also the zone mainly impacting agricultural operations. The Unsaturated Zone Technical Committee works towards synergizing research activities on the various topics related to the unsaturated zone, and to highlight key issues, solutions, results, and researchers.

The unsaturated zone (UZ) community has been focused on the fundamental processes that govern flow and transport processes in the vadose zone and their engineering applications. Increasingly, we realize that these processes play a vital role in regulating subsurface biological and geochemical dynamics as well as land-surface processes. Therefore, the community has endeavored to form tighter partnerships with bio-geo-sciences and atmospheric and climate science in addressing contemporary challenges in water, climate, and food. Three critical questions that are of relevance to UZ are: 

  1. How do small-scale processes and heterogeneities in the unsaturated zone influence and regulate fluxes within and across the UZ across multiple spatial and temporal scales?
  2. How do resiliency and thresholds of UZ processes respond to anthropogenic disturbances, and how do they vary across climates, biomes, and geological settings?
  3. How can we harness the full potential of rapid advances in data science as well as communication and measurement technologies in developing predictions and decision support tools that benefit society?

Technical Committee Meeting

The Unsaturated Zone Technical Committee will convene next during the 2019 AGU Fall Meeting. 

Time: 6:45am – 7:45am

Date: Monday, 9 December

Venue: Marriott Marquis, Nob Hill A, Lower B2

Fall Meeting sessions by the UZTC

Session ID Title Description

Conveners (UZTC
members highlighted)

The Food-Water Link and Nonpoint Source Flux Impact on Groundwater, Vadose Zone, and Surface Water Quality I Nonpoint source (NPS) fluxes in vadose zone, groundwater, and at their interface to surface water are critical to societal issues including agricultural sustainability, food security, drinking water quality, ecosystem health, and global change.  Better understanding is needed of bio/geo/hydro/chemical and anthropogenic factors affecting diffuse mass fluxes of nutrients, pesticides, emerging contaminants, trace elements, greenhouse gases and other chemical/biological agents. Strategies are emerging to monitor the sources and fate of NPS fluxes and to more effectively control and remediate water quality. We invite contributions assessing NPS transport processes and flow routes using field, laboratory, and modeling approaches (lab, plot, or watershed/(sub)basin scale); presentations on innovative remediation options to control or intercept NPS pollution in rural or urban settings; on studies that address linkages between chemical, biological, hydro(geo)logical, climatological, and/or social factors affecting NPS fluxes, and on studies linking agricultural practices to NPS fluxes to develop sustainable management options. Rozemeijer Joachim
Green Christopher
Basu Nandita
Harter Thomas
Environmental Vadose Zone Hydrology The vadose zone provides an important linkage between the Earth’s surface and groundwater, and influences a wide range of critically-important environmental hydrologic phenomena such as recharge, ET, and subsurface transport. However, many vadose zone dynamics and hydrologic controls are still poorly understood due to the random and structural heterogeneities that exist across scales in both time and space, the complexities and non-linearities that occur within and between processes, and the difficulties associated with quantifying and monitoring these processes. We solicit presentations that advances our understanding of dynamic hydrologic and (bio)geochemical processes in the vadose zone. Topics may include but are not limited to: unsaturated and multiphase flow and transport, effects of heterogeneity including preferential flow, climate change-induced vadose zone processes, measurement or monitoring techniques applicable to the vadose zone, and uncertainty in vadose zone flow and transport prediction. Smits Kathleen
Sayde Chadi
Joaquin Jimenez-Martinez
Hsu Shao-Yiu
Water and Society: Groundwater in a Changing Climate Groundwater-climate interactions are dynamic and affect subsurface hydrological processes, groundwater quantity, groundwater quality, and the potential for shallow geothermal energy. However, the impacts of natural and anthropogenic disturbances on the variability of the groundwater system as well as their associated social, economic, and public health implications have not been fully addressed in a comprehensive manner. Furthermore, management regimes do not necessarily take into account this variability. This session will explore natural- and human-induced changes in the spatiotemporal and thermal variability of the groundwater system and how they affect the water and energy budget. It will also examine how management regimes strive for sustainable quantitative groundwater management. Particular focus will be given on how stakeholders craft collective allocation rules that resolve competing societal objectives while harnessing the spatial and temporal variability of groundwater resources. Benz Susanne
Lo Min-Hui
Rouillard Josselin
Li Yusong
Application of Artificial Intelligence/Machine Learning to enhance process understanding of pristine and agriculture-intensive watersheds An understanding of watershed functions is required to quantify effects of climate change and extreme weather on the downstream delivery of water, nutrients, carbon and metals – all of which affect freshwater resources and agriculture in the long term. Simultaneously, a multi-scale understanding of vadose zone processes is required to quantify the effects of water and nutrient dynamics – factors that affect water quality and agriculture in both the short and long term. We invite contributions describing use of artificial intelligence, machine learning, and other data-driven techniques that involve (1) aggregating a variety of data sources, (2) modeling uncertainty associated with data used to fit or initialize watershed-scale models, (3) computational techniques to account for data challenges inherent in models, (4) modeling flow of water and nutrients in the vadose across space and time scales, and (5) modeling impacts of hydrological processes on agriculture. Mital Utkarsh
Jana Raghavendra
Dwivedi Dipankar
Xie Yuying


The Unsaturated Zone Technical Committee is excited to announce, with the help of the Hydrology Section leadership, a new award for the two top-rated OSPA entries from the Environmental Vadose Zone Hydrology session (H053-1) at the 2019 Fall Meeting with cash prizes! The awards will be in the amount of $300 to the first placed presenter, and $200 to the second. The presentations will be ranked based on the OSPA judges' evaluation scores.


The Committee

The Committee takes an active role in directing the unsaturated zone research community within AGU. 
Please contact the Chair if you are interested in becoming involved with this committee.

Yusong Li (Chair), University of Nebraska-Lincoln
Joaquin Jimenez-Martinez (Deputy Chair), Swiss Federal Institute of Aquatic Science and Technology
Teamrat A. Ghezzehei (Past Chair), University of California, Merced
Thomas Phelan, U.S. Air Force Academy
Raghavendra (Raghu) Jana, Skoltech, Russia
Manoj Shukla, New Mexico State University
Thomas Harter, University of California – Davis
Joshua Larsen, University of Queensland, Australia
Kathleen M. Smits, University of Texas, Arlington
Clare Robinson, University of Western Ontario
Wei Zhang, Michigan State University
Chadi Sayde, Oregon State University
Ryan Stewart, Virginia Tech
Lirong Zhong, Pacific Northwest National Lab
Veronica Morales, University of California – Davis
Jason Gurdak, San Francisco State University
Ian Molnar, University of Edinburgh
Shahab Karimifard, University of Nebraska-Lincoln

Brief bio's of the committee members can be found here.