Yuval Shani

Dr. Gabriel Rubanenko, Dr. Steven Brounman & Dr. Igor Furman Prize for Excellence in Water Research, 2005.

Department of Environmental Hydrology and Microbiology
Zuckerberg Institute for Water Research
Jacob Blaustein Institutes for Desert Research
Ben-Gurion University of the Negev

I was born in Tel-Aviv in 1975. For most of my childhood I lived in a village called Even-Yehuda which is located in the center of Israel. During high school I was a member of the youth group (Hug Noar) of the Society for the Protection of Nature in Israel, traveling all over the country as part of my activities with them. After serving in the army for three years, I worked in the fields of Ramot Hashavim, a moshav (agricultural village), for half a year. After traveling for eight months in Latin America, I started my bachelor's degree in October 1998 in Soil and Water Sciences at the Faculty of Agricultural, Food and Environmental Quality Sciences in The Hebrew University of Jerusalem's Rehovot campus. I finished my studies in 2001 and then moved to the south of Israel where I started working as an irrigation manager in an agricultural cooperative. After gaining some work experience there I traveled to South Africa for six months. In October 2003 I started studying for my master's degree at the Zuckerberg Institute for Water Research, focusing on Direct Measurement of Flood Water. Currently I am about to complete my M.Sc. degree, and consider my next steps in life.

Description of research:

Floodwater Percolation and Groundwater Recharge in Arid Lands

Supervisor: Dr. Ofer Dahan

The overall scope of this study is to investigate the critical relations between floodwater and recharge processes in shallow alluvial aquifers from both natural, undisturbed ephemeral streams and percolation/storage reservoirs. This research is an integrated study that simultaneously monitors and analyzes all three hydrological domains controlling the recharge process: (1) the flood hydrograph as the water source for the vadose zone; (2) the deep vadose cross section response to flood events; and (3) response of groundwater to both the flood event hydrograph and the vadose zone moisture profile variation.
In order to investigate the above, a new technique of Time Domain Reflectometry (TDR), which enables continuous, real-time, moisture measurement through the entire vadose zone, is being used. The technique allows multi-level installation of Flexible TDR Probes to any desired depth with minimal disturbance of the soil column structure.
To date three monitoring stations have been constructed in the Arava valley, one on the Arava stream by Ein Yahav, and two others by the Tzukim reservoir. Flood events and their impact on groundwater recharge were recorded through three major natural floods in December 2003, January 2004 and October 2004. In addition, a controlled percolation experiment under ponded conditions was carried out in May 2004.
Preliminary analysis of the data shows a quick response of the vadose zone and groundwater to the flood events in open stream channels, while a significant decrease in percolation rate was observed below the reservoirs due to sealing of the reservoir bottom by silt.
The vadose zone moisture profiles will be processed using two modeling approaches: (1) water mass balance over the entire cross section, and (2) numerical modeling using unsaturated zone flow models.