Can Rain Solve the Problem?

We are missing several key pieces of information.  Hence, answering the question is more of a guess than it should be.  Things we do not know include:

  1. Historical Consumptive Use by district, especially for the Upper Republican NRD.  The reason the Consumptive Use for the URNRD would be useful is because the URNRD has accurate pumping data.  The other districts in the Basin do not.

  2. Allocations by district.  Again, for the same reason, only the URNRD has accurate historical pumping data.

  3. Historical Consumptive Use by surface users.

  4. Consumptive Use caused by prior year pumping.

  5. The DNR says that the Consumptive Use increases each year, even if no new wells are added.  It does not tell us how much that increase is.

  6. Complete input data unavailable.  The data used by the Republican River Compact Administration is not available and, hence, not verifiable.

The DNR could generate this data.  The NRDs could require the DNR to generate this data.  The Legislature or Governor could require the information.  As of October 2005, none of these government entities wish to deal with the issue.  For the purposes of this article, Consumptive Use and Depletion are used interchangeably.

In graph 1, Nebraska is okay as long as the blue area is above the red line.  Several things to note:

  1. The 2005, 2006, 2007 red line estimate is provided by the DNR in one of its worksheets.  It is not an official estimate and is about 20,000 AF less than the average. 

  2. The dark line is a trend line.  It shows the expected depletion based on historical depletions. By our estimate, the depletions increase by 1% each year.

  3. The amount of ground water pumped in the Basin is not statistically related to depletion. Because pumping causes a delayed effect on the stream, one cannot use pumping to estimate depletions nor adjust pumping and expect to have any noticeable effect on the stream for many years.


Graph 1

Graph 2 shows the estimated pumping for the Basin overlaying the Allocations and Depletions data.  The pumping numbers are the URNRD data multiplied by two.  The point is that pumping and depletions are not statistically related. The graph is the same except on a different scale.


Graph 2

 


Graph 3

Precipitation data for 2005 is projected through the end of 2005.  As of October 8, 2005, 88% of the annual precipitation has been received.  Actual received 19.04", projected is 21.64", based on the last 24 years of average precipitation.

The point of graph 3 is to show that if the Allocation were directly related to precipitation, the allocation should have been significantly higher in 2003 and 2004.   There is a correlation in some years and not in others.  1983, 1991, 1992, 1994, 2003, and 2004 are examples of where precipitation and allocation are disjointed.  

In 2004, precipitation was above normal at 23.24 inches while average is 21.87 inches (or 1.37 inches above normal for the entire Basin), yet the allocation for the Basin was at its lowest point in the last 24 years. 

In other words, there are other factors besides precipitation that determine the allocation for the Basin.   These other factors include when the precipitation falls, the quantity that falls at one time, and the evapotranspiration rate.

In 2003, the Basin received 85% of the normal precipitation, and Nebraska was 25,000 AF over its allocation.

In 2004, the Basin received 106% of the normal precipitation; and Nebraska was 36,000 AF over its allocation, even though its use was less.

As of October 8, 2005, the Basin has received 87% of the normal precipitation. It is normal to have received 88% by this date.  So, the Basin is exactly at average for 2005.


Graph 4

  1. Nebraska is currently 61,000 acre feet over its allowance.  This reflects 2003 and 2004 data.  Only 2003 through 2007 data matters.

  2. Nebraska has failed to live within its allocation 7 out of the last 24 years, or 29% of the time.  

  3. The average surplus allocation is 60,000 AF in the 18 years Nebraska underused its allocation. However, 65% of the time in the surplus years, the surplus is less than 60,000 AF. 

In other words, 71% of the time over the last 24 years, Nebraska had a surplus.   Forty-five percent (45%) of those surplus years will generate enough of a surplus to eliminate the 2003 and 2004 overage. 

If one used this data only, one might conclude that Nebraska has a 32% chance of resolving the problem in each year 2005, 2006, and 2007. Obviously, the weather does not respond to statistics, so the numbers are only useful in the long term.

Can rain solve the problem?  Unfortunately, there is insufficient data to answer the question.  Even if the Basin has more than normal precipitation, it does not mean that it will have a good allocation and, hence, be in compliance.   This means it is inaccurate to blame the drought for the problem..  Nebraska has agreed to be governed by a computer simulation that makes it almost impossible to predict with any accuracy whether the State will be in compliance.   Land retirement programs will cause a long-term benefit to the stream, but they will have no meaningful effect in the short term.  The only practical way to assurance compliance is to supplement the allocation in the year after Nebraska has been found to be out of compliance. Any other method of compliance will result in adding uncertainty.