Pat distributed outline of two methods for determining measurable change . PAW believes SAR or salinity should be used to determine measurable change because those are the parameters that will impact uses in Montana. There is no SAR data from the 1990s to use as a baseline. Therefore, it is not reasonable to assume that 1970s data can be extrapolated though the 1990s because the 1970s data includes a lot of salty water discharged from the Salt Creek oil field. PAW- indicated that SC data exists for the 1990s and that SC is related to SAR, so the lack of SAR data in 1990s is not important.
PAW wants to look at seasonal changes only.
Pat Newby- Believes that SC and SAR are not correlated. He says seasonality is removed from his method and his method uses all the data throughout the year, which makes it more statistically powerful. But such a review would take a significant amount of time and money, so it was decided not to do such a review. Sensitivity of his method to measure change in alkalinity is about 1 cfs of measured CBM flow. For Na, it can detect a change due to 4 cfs of CBM water reaching the river.