Analysis of Historic Changes in Spokane River Flows

John Porcello, LHG and Jake Gorski, EIT of GSI Water Solutions, Inc. presented a Screening Level Analysis: Causes of Historical Changes in Seasonal Low Flows in the Spokane River at the Spokane Aquifer Joint Board Meeting on December 3, 2015.
View / Download the GSI presentation slides or the presentation with notes.

The trend line for 1900-1950 shows a strong correlation between seasonal low flows and time, as shown by the high coefficient of determination (R2=0.7254). In contrast, the period 1950-2007 has a very weak trend over time (R2 is much less than 10 percent). This raised several questions in the minds of GSI and SAJB personnel about what happened historically and what those historical conditions might mean for the current continued decline that is being seen in seasonal low flows.