Problem 3: Base flows

EDITOR'S NOTE -- The following is the fourth in a series by Steve Smith of WaterClaim.com concerning the ongoing Republican River dispute:

Problem 3 with the Model - Input Data -- Base Flows

Base flow is the amount of water oozing from the aquifer into the streams. Stream flow is base flow plus run off from precipitation events. Base flow cannot be greater than the total stream flow.

The RRCA estimates the base flow for 15 different sites on the Republican River and its tributaries since 1918.

Via an open records request, WaterClaim obtained and has analyzed base flow data from the Nebraska Department of Natural Resources. We also looked at stream flow data from the USGS.

We plotted the base flows used by the Model and compared them to the stream flows. Base flows used by the computer simulation that governs Nebraska's compliance are much higher than stream flows on at least one stream. That is an impossibility. This means that historic base flows are artificially high. It also means that when we compare historic base flows to current base flows, the drop attributed to groundwater pumping is inflated.

There is an actual drop in stream flows in the Republican River Basin, but the data fed into the simulation exaggerates the reduction in base flow by a large amount. The simulation compares base flows from 1918 to base flows now and assigns the difference to depletions caused by groundwater pumping.

This is probably an unintentional problem. We provide documentation, using DNR and USGS data files, available on the WaterClaim site. If the exports verify that the problem we point out is correct, then it means that the base on which the States have determined compliance must be recalibrated and recalculated. It has a significant effect on whether Nebraska is or is not in compliance.

This is something that the DNR is able to verify without much difficulty. Other parties, such as the NRDs, could also check out the documents. If they find what we have found, they should require a correction before continued participation in the process. Nebraska could decline to certify the results until the data is corrected. We have provided document references for easy analysis, should those responsible choose to look.

Steve Smith,

WaterClaim.com