Surface Water Prize


mohamed_khayet_souhaimiDr. Larry W. Mays (Arizona State University).

The prize is awarded to Dr. Mays for comprehensive work in surface water hydrology and water resources engineering, culminating in three leading and innovative textbooks in the field and the development of optimization models in practical hydrology for current problems, including real-time optimal dam release during flood conditions and watershed development in urban areas.

The books by Mays, with their breadth, depth and broad relevance, have made a unique and tangible contribution to water resources engineering and the management of water resources throughout the world.

His books include Ancient Water Technologies (2010), Ground and Surface Water Hydrology (2012), and Integrated Urban Water Management: Arid and Semi-Arid Regions (2008). One of his most unique contributions is to demonstrate how ancient water technologies can be applied today to manage water resources in concentrated urban areas and alleviate many present-day sustainability problems.

Winner Profile

Dr. Larry W. Mays is Professor for the Civil, Environmental, and Sustainable Engineering Group, School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe.


• Ph.D. 1976; University of Illinois at Urbana-Champaign, Civil Engineering
• M.S. 1971; University of Missouri at Rolla, Civil Engineering.
• B.Sc. 1970; University of Missouri at Rolla, Civil Engineering.

Selected Awards:

2002: Association of American Publishers PSP Award
1999: Distinguished Alumnus Award, Department of Civil Engineering, University of Illinois at Urbana-Champaign.
1993: Quentin Mees Research Award, Arizona Water and Pollution Control Association.
1992: Engineer of the Year in Education Award, Arizona Society of Professional Engineers.
1989: Certificate of Commendation for Outstanding Achievement in the Field of Water Resources, National Association of Water Institute Directors and the National Association of State University and Land Grant Colleges.

Acceptance Speech

I am deeply honoured to receive the prestigious Prince Sultan Bin Abdulaziz International Prize for Water – The Surface Water Prize. I am very thankful to HRH Prince Khaled Bin Sultan Bin Abdulaziz and his council for selecting me for this prize and to be able to be here this evening to accept this honor.

I deeply feel that my 39 years of university research and teaching efforts in the areas of water resources engineering and hydrology has paid off with this great honor.

A large part of my original research over the years was focused on water resources and surface water hydrology, especially for urban stormwater systems, using optimization and risk/reliability procedures, for the design and operation of these systems.

I have also developed optimization/simulation models for the real-time operation of river-reservoir systems, particularly under flooding conditions. My efforts over the years in optimization and risk/reliability for hydrologic analysis, eventually moved my research efforts into water resources sustainability issues.

My work in surface water hydrology and water resources has culminated in several reference and textbooks that I have authored or edited over the years. Three of my more recent books were noted as part of my efforts for this recognition tonight.

The book, Integrated Urban Water Management in Arid and Semi-Arid Regions, was the result of my volunteer work for the United Nations UNESCO-IHP Program. This book was one of the main outputs of the Integrated Urban Water Management in Specific Climates project of UNESCO-IHP.

The second book, Ground and Surface Water Hydrology, was a result of my 38 years of university teaching of hydrology and water resources engineering. So basically this is a result of my love for teaching hydrology. A rigorous, unified, numerical, and analytical approach is used throughout the book bringing together a balance between theory and application.

I recognized years ago that developing nations in arid regions in the world, with a fast growing population and limited economic resources need special attention. One of my most prized efforts has been the work that I have initiated in the study of ancient water technologies and traditional knowledge specifically in arid and semi-arid regions, within the framework of water resources sustainability for the present and the future.

The third book, Ancient Water Technologies is a result of my interests in studying ancient water technologies as one the methodologies (traditional knowledge) for solving water resources sustainability problems, especially in developing parts of the world. Poor water management hurts the poor the most and some solutions will certainly be found in traditional knowledge through techniques that have been around for millennia More recently I co-edited the new book, Evolution of Water Supply through the Millennia, published by the International Water Association.

This is a grand moment for me with the feeling that my life’s journey in education, research and writing in water resources and hydrology has definitely been a work of love for me which has led to my interest in water resources sustainability particularly in developing parts of the world.

The Prince Sultan Bin Abdulaziz International Prize for Water provides visibility to the important problems associated with water sustainability issues around the world and will promote innovative solutions for our future of water sustainability particularly in developing parts of the world. I applaud and thank the organizers of the Prince Sultan Bin Abdulaziz International Prize for Water, the Prize Council, and His Royal Highness Crown Prince Sultan Bin Abdulaziz himself, for this extraordinary recognition of my work.

Larry W. Mays

Winning Work

1. L.W. Mays, Editor-in-Chief, Ancient Water Technologies. 2010. Springer. The Netherlands.

2. L.W. Mays. Ground and Surface Water Hydrology. 2012. John Wiley and Sons, Inc.

3. L.W. Mays, Editor-in-Chief. Integrated Urban Water Management in Arid and Semi-Arid Regions. 2009.UNESCO-IHP. Taylor and Francis. London.

4. Ahmed, E-S.M.S. and L.W. Mays. 2013. "Model for Real-Time Optimal Dam Releases during Flooding Conditions." Natural Hazards, Springer Vol. 65, 1849-1861, 2013.DOI 10.1007/s11069-012-0444-6.

5. Chill, J. and L.W. Mays. 2013. "Determination of the Optimal Location for Developments to Minimize Detention Requirements", Water Resources Management, 27(15), 5089-5100.

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Creativity Prize (Co-Winners)


psipw5thwinnersteam 4web 41. The GPS Reflections Group led by Dr. Kristine M. Larson (University of Colorado at Boulder), and including Professor Eric E. Small (University of Colorado), Dr. Valery U. Zavorotny (NOAA) and Dr. John J. Braun (UCAR).

The prize is awarded to this team of researchers for their discovery that standard geodetic GPS instruments are sensitive to hydrological influences and the subsequent development of a new, unexpected, and cost-effective technique, GPS Interferometric Reflectometry (GPS-IR), to measure soil moisture, snow depth, and vegetation water content.

GPS-IR is based on the discovery that the “noise” (interference pattern) observed with ordinary GPS instruments correlates with the water content of the reflecting surface in the vicinity of the receiving antenna.

This method of measuring soil moisture complements the cosmic ray technique (COSMOS) of Dr. Marek Zreda and Dr. Darin Desilets, a work previously honored by PSIPW back in 2010. Whereas COSMOS provides soil moisture averages over a circular area of radius 300 m to a depth of several decimeters, continuously-operating GPS receivers can be used to estimate soil moisture variations over areas of radius 50 m to a maximum depth of 6 cm, with greatest sensitivity to the upper 1 cm of soil depth at near saturation.

Furthermore, GPS-IR has the advantage of relying on an existing GPS infrastructure installed by surveyors and geoscientists that covers an increasingly large portion of the global surface (including more than 12,000 continuously-operating GPS systems on and near a wide range of soil and vegetation types around the world).

Its ability to reliably measure and track snow depth is extremely important because on-site snow distribution data are sparse and remotely sensed data are coarse-scale and imprecise. The ability of GPS-IR to sense and track vegetation growth complements conventional remote sensing data that have limited temporal coverage and do not work well in the presence of clouds.


Winner Profiles

Dr. Kristine M. Larson

Dr. Kristine M. Larson is Professor in the Department of Aerospace Engineering Sciences and the Environmental Engineering Program, University of Colorado at Boulder.


• Ph.D. 1990; Institute of Geophysics and Planetary Sciences, Scripps Institution of Oceanography, University of California at San Diego, Geophysics.
• B.A. 1985; Harvard University, Engineering Mechanics.

Selected Awards:

2013: University of Colorado Boulder Faculty Assembly Award for Excellence in Research 
2006: Japan Society for the Promotion of Science (JSPS) Award.
2005: AGU Geodesy Section Award, recognizing major advances in geodesy.
1997-1998: National Science Foundation POWRE Award.
1994: NASA Group Achievement Award, Jet Propulsion Laboratory, in recognition of significant advances developing new techniques that permit the determination of an absolute global reference frame accurate to one centimeter with measurements from the Global Positioning System.
1993: National Science Foundation Career Advancement Program Award.
1992: NASA Group Achievement Award, Jet Propulsion Laboratory, in recognition of the pioneering OASIS/GIPSY software package that has set the world standard for global positioning system-based orbit determination and global geodetic measurement accuracy.


Dr. Eric E. Small

Dr. Eric E. Small is Professor in the Department of Geological Sciences, University of Colorado at Boulder.


• Postdoctoral Research Associate, 1998; Department of Civil and Environmental Engineering, MIT.
• Ph.D. 1998; Earth Sciences Department, University of California Santa Cruz.
• B.A. 1993; Williams College, Williamstown, Massachusetts, Geology.


Dr. Valery U. Zavorotny

Dr. Valery U. Zavorotny is a Physicist at the Physical Science Division of the Earth System Research Laboratory, National Atmospheric and Oceanic Administration (NAOA).


• Ph.D. 1979; Institute of Atmospheric Physics, USSR Academy of Science, Moscow, Physics and Mathematics.
• M.Sc.; Warsaw Technical University, Poland, Solid State Technology.

Selected Awards:

2014: Distinguished Lecturer, IEEE/Geoscience and Remote Sensing Society.
2010: Recognition for Best Reviewers for the IEEE Transactions on Geoscience and Remote Sensing (TGRS).


Dr. John J. Braun

Dr. John J. Braun  is a Project Scientist for the Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) Program at the University Corporation for Atmospheric Research (UCAR).


• Ph.D. 2004; University of Colorado at Boulder, Aerospace Engineering Sciences.
• MS. 1997; University of Colorado at Boulder, Aerospace Engineering Sciences.
• B.A. 1991; University of Colorado at Boulder, Physics and Mathematics.

Acceptance Speech

First, I wish to thank the Prince Sultan Bin Abdulaziz Prize Council for recognizing our group’s work to develop cost-efficient instrumentation to measure soil moisture, snow depth, and vegetation water content. It is a great honor to be in Riyadh and to receive this prize. It is a pleasure to share this with my colleagues Eric Small, John Braun, and Valery Zavorotny.

I am a GPS geodesist. Generally this means that my job is to measure how the ground moves. How does a GPS geodesist win a prize given for measuring water? It turns out it started when I was trying to measure how the ground moves during an earthquake. To improve how well GPS could do this, I began to work on eliminating the effect of ground reflections on the GPS signals because they produce inaccurate positions. Eventually we were successful at deriving empirical corrections for ground reflections; it was this initial work that ultimately led me to try to measure ground reflections on purpose - specifically for hydrological applications.

While in principle ground reflections measured by a GPS instrument will be sensitive to changes in water content, there was a small problem to overcome: GPS instruments are designed to reject ground reflections. But if these technical difficulties could be overcome, we would be able take advantage of existing instrumentation operated by geophysicists and surveyors - installed to measure non-hydrologic parameters such as fault motions and land boundaries. Given that installing and maintaining any kind of scientific network is expensive, this is an incredible cost-savings. An added benefit of using GPS instruments to measure hydrologic parameters is that it increases the stakeholders for those networks. Going forward, I envision these stakeholders working together to build new GPS (and GNSS) networks for both traditional positioning and hydrological users. This could be particularly useful in regions that are not currently operating soil moisture networks.

I would like to end this short speech with both some professional and personal acknowledgements. First, none of this water cycle research could have been done without the Global Positioning System, which is truly a technological achievement in and of itself. What started out as just an idea became a reality via generous funding from both NSF and NASA. Having shown our ideas worked at a few sites, we were able to demonstrate it on a broader scale by taking advantage of the EarthScope Plate Boundary Observatory. I am very grateful to the people that designed, installed and maintained that GPS network. For myself, I want to thank my family, but especially my father, for always encouraging me to pursue a career in engineering and my husband for supporting me during these past twenty-five years.

Kristine M. Larson

Winning Work

1. Larson, K.M., E. Gutmann, V. Zavorotny, J. Braun, M. Williams, and F. Nievinski. "Can We Measure Snow Depth with GPS Receivers?" Geophys. Res. Lett., 36, L17502, doi:10.1029/2009GL039430, 2009.

2. Larson, K.M., J. Braun, E. E. Small, V. Zavorotny, E. Gutmann, and A. Bilich. "GPS multipath and its relation to near-surface soil moisture", IEEE-JSTARS, Vol 3(1), pp. 91-99, 10.1109/JSTARS.2009.2033612, 2010.

3. Zavorotny, V., K. M. Larson, J.J. Braun, E. E. Small, E. Gutmann and A. Bilich. "A physical model for GPS multipath caused by ground reflections: toward bare soil moisture retrievals", IEEE-JSTARS, Vol. 3(1), pp. 100-110, 10.1109/JSTARS.2009.2033608, 2010.

4. Small, E.E., K.M. Larson, and J. J. Braun. "Sensing Vegetation Growth with GPS Reflections", Geophys. Res. Lett., 37, L12401, doi:10.1029/2010GL042951, 2010.

5. Chew, C.C., E.E. Small, K.M. Larson, and V. Zavorotny. "Effects of Near-Surface Soil Moisture on GPS SNR Data: Development of a Retrieval Algorithm for Volumetric Soil Moisture", IEEE Trans. Geo. Rem. Sens., doi:10.1109/TGRS.2013.2242332, 2013.

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6th Award (2014)

Prizewinners for the 6th award were announced at the Prize Council meeting convened in Riyadh on 12 October 2014, which was presided over by PSIPW Council chairman, HRH Prince Khaled Bin Sultan Bin Abdulaziz.

International Water Portal



The International Water Portal is a joint effort of the United Nations and the Prince Sultan Bin Abdulaziz International Prize for Water (PSIPW). It is a comprehensive online forum and database for all parties that are professionally involved with water. It combines the functionality of a professional database, an online digital library, and a professional networking site.

The portal can be accessed at: .

Read the Brochure (pdf).


waterportalthumbnailhomepageshotThe water portal was originally envisioned as a water professional database, which would host information about water researchers from around the world. It was commissioned as one of the resolutions published at the United Nations 1st International Conference on the Use of Space Technology for Water Management which was held in Riyadh in 2008 and co-organized by UN-OOSA, UNESCO, Prince Sultan Bin Abdulaziz International Prize for Water (PSIPW), and the King Abdulaziz Center for Science & Technology (KACST).

After preliminary development of the database by the PSIPW team, the vision expanded to being an interactive database for water research, water organizations, companies, and water professionals, with added networking functionality where water specialists can contact one another, exchange information, and add to a searchable online water library.

The Water Portal's goal is to gather together all parties involved in the water issues in one place to enhance international cooperation, communication, and access to information.

This new vision was presented by the PSIPW delegation at the following meeting of the Committee for the Peaceful Uses of Outer Space (COPUOS) in Vienna in 2009, where it was endorsed, adopted, and renamed as the International Water Portal. It was agreed the portal will be hosted by PSIPW.

The International Water Portal was officially launched during the COPUOS Scientific and Technical Subcommittee meeting that was held in Vienna Austria from 6-17 February 2012.