Introducing Harald Kling - Collaboration Across the Big Pond

bridges vol. 18, July 2008 / News from the Network: Austrian Researchers Abroad

by Christoph Derndorfer

“Great, that’s exactly what we need here!” is a common reply when Harald Kling tells people that he is working in hydrology. However this only started occurring when he moved to Tucson in Arizona. Back in the days in his native Austria, he always had to explain what the field of hydrology was all about …

Kling at desk
Harald Kling

In 2007, Kling received funding through a FWF Erwin-Schrödinger Fellowship that allows him to spend 16 months doing research at the Department of Hydrology and Water Resources at the University of Arizona. His research focuses on modeling the transformation of precipitation into runoff, which is applicable in a variety of fields: Classic examples would be flood prediction and the impact of land use on water resources. Additionally, a wider range of issues such as comprehensive climate change impact evaluation, questions on groundwater recharge, and certain aspects of hydropower generation depend on the accurate model of precipitation and its impact on runoff.

{access view=guest}Access to the full article is free, but requires you to register. Registration is simple and quick – all we need is your name and a valid e-mail address. We appreciate your interest in bridges.{/access} {access view=!guest} Just "a standard research job"

While a researcher at his alma mater in Austria, the University of Natural Resources and Applied Life Sciences (BOKU) in Vienna, Harald Kling had focused on the water balance, modeling its spatial and temporal distribution in Austria. The water balance "describes how precipitation is partitioned into runoff, evapotranspiration, and water storage, either in the snow layer or in the ground, thus being a basis for any kind of water resources-planning," Kling explains. In simple terms, the estimate consists of precipitation being split into three variables:

  • Runoff, which is the overall water flow in a region
  • Evapotranspiration, which is the sum of evaporation and transpiration - the latter being evaporation of water from plants, which accounts for roughly 10 percent of the atmosphere's overall moisture
  • Storage change, which is changes in the snow layer, soil moisture, or ground water.

Kling was initially attracted to the topic via what he calls “a standard research job” at the BOKU that focused on water-balance modeling for the whole Danube basin. In his studies he had focused on hydrology after being enticed by a friend’s comment on how interesting the field was. As a child, he enjoyed redirecting streams with his own typical child-like constructions made of sticks and stones. He also liked being in the water when kayaking with his father. Kling recalls, „So I always liked rivers and I liked this idea of hydrology.“

He also participated in a project to set up a flood-prediction system for the Traisen River in Lower Austria. After five years of working in the field, his interest shifted more upstream and he started working on his dissertation. In close collaboration with Hans-Peter Nachtnebel, the head of the institute, he also contributed to the Hydrological Atlas of Austria which provides a comprehensive overview of hydrological information from Austria.

The work on his dissertation introduced him to the fact that hydrological researchers are strongly dependent on actual measurements of precipitation and runoff as a basis for their projects. The main issue with this dependence is that measurements might be available for one particular area, although what’s really needed is an accurate and consistent estimate for a larger area rather than very specific points. In making these estimations, it is difficult to balance different uncertainties in both measurements and modeling. So when dealing with 188 basins for his Danube project, the main challenge for Harald Kling was to come up with procedures which resulted in good estimates for the whole study region.

Austrian models working in the Sierra Nevada

Precipitation Runoff Model for the Sierra Nevada
Precipitation Runoff Model for the Sierra Nevada (click to enlarge)

This background directly leads to Kling’s FWF Erwin-Schrödinger Fellowship and his current research in Arizona. The goal of his project is to improve the predictive capability of precipitation-runoff models by better accounting for various uncertainties during calibration. At a recent conference, Kling presented his research within the framework of a project by the National Weather Service (NWS) that focuses on flood predictions and stream flow forecasting for the United States. The “Distributed Hydrologic Model Intercomparison Project” pits various modeling approaches against each other and compares the results of their simulation with actual data from the field. As it turns out, the approach developed by Kling’s institute in Vienna and fine-tuned by himself shows promising results. The NWS has asked for more information about it and it is possible that the agency will use some of Kling’s research for future modeling, especially in the Sierra Nevada basin where the Austrian model worked very well. It remains to be seen what the final outcome of the project is, but it looks like another step towards more accurate prediction models.

Regarding his overall experience in Arizona, Kling appreciates the opportunity to collaborate with people like his supervisor Hoshin V. Gupta, whom he considers one of the world leaders in hydrology. Due to the lack of water in the area, hydrology issues are important in Arizona, “a possible reason why the university’s hydrology program is so good.” according to Kling. Even the reviewers of his research proposal in Austria commented that “it’s probably the best place to go.”

Throughout his work, Kling has always valued the high standards and cooperation with colleagues in both Vienna and Arizona. Having worked at both universities allows him to see the differences between their approaches to science. In Austria the focus of projects was to “directly use what you do” while his project at the University of Arizona gives him significantly more freedom when it comes to the focus of his research. Another aspect of working in Arizona, which he appreciates, is the regular meetings with colleagues who work on different projects within the same field. The resulting fruitful discussions are part of the extensive knowledge exchange that Kling sometimes misses in Austria. Another thing that he will miss is the good selection of restaurants on campus in Arizona. Before going to the United States people had told him that he would have a hard time finding good food there. Turns out the choice is actually much preferable to what BOKU has to offer.

For his remaining months in Arizona, Kling plans to write two papers based on the results of his research, and intends to further evolve model diagnostics via projects such as the NWS comparison study. Upon his return to Austria he hopes that the results of his research will be applied in projects at the BOKU, giving his colleagues an opportunity to directly benefit from his work abroad. While he maintains regular exchange with his colleagues at BOKU, he comments on the fact that “there’s simply a much better knowledge exchange when you’re at the same place, in the same room, working on things together.”

Asked about his plans for the future, Kling mentions the importance of “always working on stuff that interests me and being open.” A recent hearing by the House Science and Technology Committee on current water supply challenges stressed the importance of further research in the area of Kling’s expertise. Combined with the fact that water-related challenges are receiving more public attention, Harald Kling might soon find himself explaining his research to random people in the supermarket – even in Austria.


The primary source for this article was a phone interview conducted with Harald Kling on June 3, 2008.


Department of Hydrology & Water Resources, University of Arizona (accessed May 27th, 2008)

The Water Cycle (Water Science for Schools) (accessed May 27th, 2008)
U.S. Geological Survey

Abstract: Hydrological Atlas of Austria (accessed June 2nd, 2008)
Harry Lins
U.S. Geological Survey

Distributed Hydrologic Model Intercomparison Project - Phase 2 (DMIP 2) (accessed June 22nd, 2008)
National Weather Service

Hearings: Water Supply Challenges for the 21st Century (accessed June 16th, 2008)
House Committee on Science and Technology