April 15, 2020 at 9:21 am

Schenk Article Examines Impacts of Climatic Variability on Northward Flowing Rivers

Xizhen "Jenny" Schenk, portrait

Dr. Xizhen “Jenny” Schenk

Dr. Xizhen “Jenny” Schenk authored an article in the journal River Research and Applications on “Impacts of climatic variability on northward flowing rivers in North America, using a paired basin approach.”

Schenk is Assistant Professor of Instruction in Geological Sciences at Ohio University.

Northward flowing rivers in continental mid- or high-latitude regions, such as the Red River in North America, are most vulnerable to an early warming trend in terms of flood risk because warmer average winter temperatures and earlier spring onset lead to more mid-winter thaws, rain-on-snow events, and heavy rainfall events on frozen ground, Schenk says. As melting water in the south moves downstream to the still frozen river channel in the north, earlier spring and ice-jam floods occur.

In recent decades, in particular, communities along the Red River experienced detrimental floods, such as the floods in 2009, 2010, and 2011 that were ranked as three of the six largest floods in its 100 years’ record.

To better prepare future river management and flood mitigation activities in a changing climate, it is urgent to understand how flood-related variables evolved temporally and spatially.

Abstract: Northward flowing rivers are the most vulnerable system to a general early warming trend in terms of flood risk. In a changing climate, how well we understand the variability of precipitation and streamflow and the correspondence between them determines the appropriateness and efficiency of river engineering activities, flood control structures, and water resource management policies. Using both time and frequency domain approaches, this study investigated variations and periodicities in precipitation and discharge of two neighboring northward flowing river basins, the Red River of the North (referred to hereafter as the Red River) basin and the Little Missouri River basin in North America. Additionally, this study also characterized whether the most dominant quasiperiodic climate variation El Niño Southern Oscillation (ENSO) affected regional precipitation and streamflow. Results indicated that the southern and central Red River basin experienced significant increases in precipitation and discharge, particularly in cold season, while the Little Missouri River basin had no statistically significant change in precipitation or discharge. The global atmospheric oscillation ENSO had little effects on the regional precipitation and streamflow increases in the Red River basin. Furthermore, strong spectral coherences and prominent annual/semi-annual periodicities in precipitation and discharge were revealed, confirming how precipitation determines frequency peaks and primary oscillation cycles of discharges in both basins. By removing broad-scale climatic driver, this study indicated that some local forcing is most likely responsible for the excessive water abundances in the Red River basin, among which agriculture land usages stand out to be the most promising driver.

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