Civil and Environmental Engineering - Master Calendar

Abstract
The magnitude 8.0 Wenchuan Earthquake in 2008 was centered in the mountains at the border of the Sichuan Basin and the Tibetan Plateau. It is said to have caused the largest number of geohazards ever recorded, including about 200,000 landslides and more than 800 quake lakes distributed over an area of 110,000 km2, 69,000 deaths and at least 5 million people rendered homeless. On the order of 1 trillion yuan (about US$150 billion) was dedicated to infrastructure reconstruction in areas ravaged by the earthquake. This effort generated an urgent need for concrete aggregate. The beds of rivers flowing from the highlands into the Sichuan Basin provided a major source for this aggregate. Massive unregulated sediment mining in these rivers led to a secondary disaster. In the case of the Shi-ting River, the river channel degraded as much as 30 m (over half the elevation drop of Niagara Falls), causing numerous infrastructure failures including the collapse of a bridge and the destruction of an irrigation intake. Here we report on a joint research effort spearheaded by Chenge An, China Institute of Water Resources and Hydropower Research, using numerical modeling to diagnose the underlying causes of the Shi-ting river disaster. We show that while overmining was the main cause of the disaster, the installation of grade control structures contributed to rather than ameliorating it. Our study resulted in methodology and software that can be used for sustainable management of sediment mining. We provide a scientific and engineering basis for strategies that can help avoid similar disasters in the future.

Bio
Gary Parker joined the faculty of the University of Illinois in the summer of 2005. He was previously an Institute of Technology Distinguished Professor in the Department of Civil Engineering at the University of Minnesota. During the period 1995-1999, he also served as Director of the St. Anthony Falls Laboratory, a water resources/fluid mechanics laboratory in the same department. Professor Parker received a B.S. from the Department of Mechanics and Materials Science of Johns Hopkins University (1971) and a Ph.D. from the Department of Civil Engineering of the University of Minnesota (1974).

Prof. Parker was elected a Fellow of the American Geophysical Union in 2003, and received the G.K. Warren Award in Fluviatile Geomorphology in 2002. He has received the Schoemaker Award twice and the Ippen Award from the International Association of Hydraulic Research, and the Einstein Award, Hilgard Prize and Stevens Award from the American Society of Civil Engineers. In 1991 he also received the University of Minnesota Institute of Technology Outstanding Teacher Award. In addition to numerous journal articles, he has written an e-book, “1D Sediment Transport Morphodynamics with Applications to Rivers and Turbidity Currents.” Parker taught undergraduate and graduate courses in fluid mechanics, river engineering, sediment transport. One of Prof. Parker's major research goals is to use the fundamental techniques of fluid mechanics and applied mathematics to treat interesting geomorphological problems. Related special research includes mechanics of river meandering; oceanic turbidity currents; sorting of mixed grain sediment by fluvial processes; bank erosion and protection using permeable dikes and vegetation; and reservoir sedimentation. Development of a mechanistic understanding of the processes involved with sediment transport in rivers and the ocean environment, and the morphologies they create, is of prime importance. River meander migration research has led to the development of computer models that predict channel shift and can therefore be used in the design of floodplain structures such as bridges, intakes, etc. In addition, research on depositional submarine fans has been found useful to oil companies as a means of helping locate oil deposits.