Trends in Annual Peak Flows and Mean Annual Flows of Selected Streams Within and Near Oklahoma: Usgs Scientific Investigations Report 2005-5192 by Charles a Perry, Ming-Ta Lee, Teresa J Rasmussen, Robert L Tortorelli (Paperback / softback, 2011)
Evidence that the magnitudes of the annual peak flow for some streams in Oklahoma are changing led to an investigation by the U.S. Geological Survey, in cooperation with the Oklahoma Department of Transportation, of trends in the magnitude of annual peak flows and mean annual flows in Oklahoma. Trends in peak flow are of particular interest to State and Federal highway agencies because trends might indicate changing levels of risk to highway structures in flood plains. The Kendall's tau test was used to identify trends and LOWESS trend lines were used as a graphical exploratory technique for trends. A peak-flow analysis used the entire period of record from 80 streamflow-gaging stations within and near Oklahoma that had a minimum of 36 years of record. Records from 3 streamflow-gaging stations indicated statistically significant upward trends in peak flows, while records from 12 stations indicated statistically significant downward trends. The records with upward trends were from streamflow-gaging stations scattered in the central and rtheastern part of the study area, while the significant downward-trend stations were all located in the western part of the study area.
Charles a Perry, Ming-Ta Lee, Robert L Tortorelli, Teresa J Rasmussen