Shift of Extreme River-Estuary Discharge in Seawater/Freshwater Estuaries under Changing Climate 

Estuaries are unique coastal regions where a river meets a large open body of water.  Recent studies show that changing climate can dramatically affect the flow dynamics and ecosystems of estuaries.  For example, observed global mean sea levels have risen steadily over the past century and are projected to increase into the future. These changes in downstream water levels affect the slope of estuarine rivers, yielding a shift in discharge patterns.  In addition, episodes of heavy precipitation show upward trends and global climate models predict tropical storm rainfall will increase under a changing climate, creating abnormal estuary discharge. While the importance of changing climate in estuaries is recognized, our ability to quantify riverine or estuarine discharge during extreme precipitation events like typhoons or thunderstorms is hindered by a lack of reliable and sustainable measurement techniques. The overall goal of the research is to examine the river/estuary hydrograph and peak discharge in relation to storm event category, precipitation, and duration to determine how the estuary responds to different levels of high-flow events.  To effectively measure riverine/estuarine discharge under extreme weather conditions, we are developing  an Automated River-Estuary Discharge Imaging System (AREDIS).  We use AREDIS to measure the discharge of the Danshui Estuary in Taiwan, Yahara River in Wisconsin, and Sheboygan River entering into Lake Michigan during high-flow events, such as typhoons or thunderstorms. These extreme measurements would allow us to better understand of the impacts of changing climate on estuaries and rivers.        (a) AREDIS on the Danshui River in Taiwan.             (b) The length of the river cross section is 400 m.     (c) AREDIS dual-camera system for far- and near-field      (d) AREDIS Remote Graphical User Interface            (e) Large-Scale PIV (LSPIV) for far-field view           (f) LSPIV for near-field view       (e) AREDIS2 at Lafollette Dam, Yahara River, WI     (f) LSPIV for non-uniform surface velocity                 (g) Discharged measured by a moving ADCP Sponsor :  Dane County Land and Water Resources Department                   NSF                  Water Resources Agency MOEA, Taiwan                  Wisconsin Hilldale Faculty/Undergraduate Research Fellowships                  Wisconsin Alumni Research Foundation                                  Status :   Active Student Investigators: Adam Bechle (PhD), Wei-Bo Chen (PhD), William Kasch (MS), Yuli Liu (Undergraduate) Graduated: Nobuaki Kimura (PhD), W.C. Huang (MS) Collaborators: Professor Wen-Cheng Liu and Dr. Nobuaki Kimura                                                             Publications Bechle, A.J. and Wu, C.H.  Estuarine discharge measurements using an image-based surface velocity technique, submitted, 2011. Bechle, A.J., Wu, C.H., Liu, W.C., and Kimura, N., Development and Application of an Automated River-Estuary Discharge Imaging System,  J. of Hydraulic Engineering-ASCE, 138(4), 327-339, 2012. Kimura, N.. Liu, W.C., Wu, C.H., Bechle, A.J., Chen, W.B.,and Huang, W.C., Flow measurement with multi-instrumentation in a tidal affected river, Water and Environment Journal, 25(4), 563-572, 2011. Liu, W.C., Chen, W.B., and Wu, C.H., Modelling effects of realignment of Keeling River, Taiwan. Proceedings of the Institution of Civil Engineers Maritime Engineering, 161, MA2, 73-97, 2008. Liu, W.C., Chen, W.B., Kuo, J.T., and Wu, C.H., Numerical determination of residence time and age in a partially mixed estuary using three-dimensional hydrodynamic model, Continental Shelf Research, 28(8), 1068-1088, 2008. Water Resources Agency MOEA, Final Report, Development of an Automated River Discharge Imaging System (ARDIS) in high discharge flows. 2008.                                                                                                           Back