a quick primer

I see confusion about the actual amounts of water involved here. As has been noted, I sometimes assume readers know more of the background information on what I am writing about than they actually may.

1889 right, 41QJ 123410. This is a Filed Appropriation Right with a priority date of 8/30/1889. Flow rate claimed is 74 cfs. Volume claimed was 53,574 a/f per year.

Water rights 123408 (1971) and 123411 (1966) are supplemental to this original right.

The 1971 right was for flow of 7 cfs and volume of 5,068 a/f. The 1966 right was for flow of 20 cfs and volume of 14,480 a/f.

This brings our totals to flow of 101cfs and volume of 73,122 a/f.  To achieve anything near this volume of use, Great Falls would have to divert the maximum flow of 101 cfs of water 24 hours a day, 365 days a year. This volume is unsupported by any historic use. Historic use is water we can prove we diverted for beneficial use prior to the 1973 Water Use Act. We cannot show we used that much water, and we cannot prove we have the capacity to store that much water.

So, in 2006, these claims were amended.

1966 right was amended to 0 volume, flow remained 20 cfs.
1971 right was amended to 0 volume but cfs was raised from 7 to 60.
1889 right remained 74 cfs and the volume was adjusted to 20,140 a/f, which volume is shared with the other two rights, as they are supplemental.

This brings the total for these three rights to flow of 154 cfs and volume of 20,140 a/f.

If you compare this flow rate to other cities, (excluding Billings) you will see it appears appropriate, and while many of them claim higher volume amounts, these typically have issue remarks and will probably be lowered during the adjudication process to conform to the flow rates. If you claim 2 a/f, but can only support usage for 1 a/f prior to 1973,  DNRC is going to take your other a/f of volume.

Now the Water Reservation comes in. Based on growth predictions, and the knowledge that the adjudication process was coming, Great Falls wanted to secure additional water beyond the 1973 historical beneficial use allocations. Municipalities were given the option of filing water reservations, which Great Falls did. This 1985 reservation claims flow of 9,155 gpm, and volume of 6,489 a/f. 

This is what Balzarini noted was about .004 % of the river flow. This reservation has no bearing on any historic use, and must be proven before it is a right.

Remember, these historic water rights listed above are based on pre 1973 water use. If we need more water in the future, we have to find it somewhere else.