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Thursday, November 05, 2009

Concerns Over Water Consumption Are Valid

By Bill Hume
Water Policy Analyst
      I write to comment on John Fleck's recent Up Front columns concerning the water deficit in the Middle Rio Grande (“Experts Wade in on Future of Rio Grande,” Oct. 20; “Cuts in Area's Water Use Still Not Enough,” Oct. 25).
       From the standpoint of hydrologic reality — what is physically happening today in the Middle Rio Grande — Fleck and the Middle Rio Grande Water Assembly have it right. However, State Engineer John D'Antonio has a procedure in place that is at least whittling away at the deficit. Municipalities that pump groundwater must acquire and retire surface water rights in ever-increasing amounts to balance their effect on the system.
       To understand the offset requirement, one must understand the hydrology it recognizes. Imagine a well as a straw stuck deep into the ground. As water is sucked to the surface, a “cone of depression” forms around the well — an inverted-cone shaped zone of earth from which the water has been removed. As the pumping continues, that inverted cone expands horizontally and extends deeper.
       The growth of the cone of depression is offset by the flow of water from the surrounding aquifer into the void created by the pumping. Eventually that flow extends up to the layer beneath the surface water streams — and water that would have otherwise continued downstream is instead drawn into the void left by the groundwater pumping.
       When the groundwater pumping first commences, it has no immediate effect on the surface flows. Hence, no offsets early in the production life of a well. But, eventually the surface flow is affected, and offsets are required. Now comes the kicker: The offset requirement starts low, but it keeps growing for as long as the well is pumped. And surface water rights must continually be acquired and retired to offset that ever-growing effect.
       Another way of visualizing this might be to imagine a cone-shaped pile of sand. That represents the surface flow. Then imagine someone digging a hole right next to the sand pile. That represents the groundwater pumping. As soon as the edge of the hole reaches the pile, sand starts cascading down the side of the pile into the hole, replacing what was removed. Continued digging removes the sand that has entered the hole — and ever more sand slides into the hole for as long as the hole is deepened and widened. Clearly, the guy who owns the sand (surface water) has an issue with the guy who is digging the hole (well pumper).
       With 50 years of municipal groundwater development out there, this is not just some legalistic abstract. It is a direct reflection of what's happening in the real world. Surface wet water continues to percolate down out of surface flows — and that is a direct and continuing reduction in the water available to meet the needs of senior water rights holders or downstream compact deliveries. So, groundwater pumpers are perpetually buying water rights to retire to offset the effects of their wells.
       This became an issue in the 2009 regular legislative session. Agricultural interests, recognizing the long-term threat to their water, succeeded in passing and getting signed House Bill 40. It exempted from municipal condemnation any “water sources used by, water stored for use by or water rights owned or served by an acequia, community ditch, irrigation district, conservancy district or political subdivision of the state.”
       D'Antonio was concerned about the HB 40's potential effect on the future ability of municipalities to meet their offset requirements. Agricultural interests were concerned about involuntary loss of their water rights.
       The agricultural interests' concerns were well-founded. State Engineer D'Antonio estimates it would take the water rights appurtenant to about 57,000 acres of middle Rio Grande valley farmland to totally offset the approximately 230,000 acre-feet per year of groundwater pumping rights already permitted. Given that the combined total acreage of pre-1907 irrigated lands, Pueblo lands and Middle Rio Grande Conservancy District reclaimed lands is somewhere between 50,000 and 65,000 acres, the train wreck is obvious.
       Are we likely to curtail or shut down our cities if they fail to meet offset requirements? Probably not. Could the cost of water for domestic and industrial use soar to unrealistic heights? Possibly — in which case urban growth might be foreclosed. Power of condemnation or not, the lure of high water rights prices to take water from agriculture is obvious. Can we just miss our delivery requirements under the compact as a long-term solution? In a word, no.
       Clearly, municipal and state growth planning that includes a hard-nosed recognition of water realities is the only strategy for confronting the offset water tap-out. And, new sources of water or new technologies for stretching the use and reuse of existing supplies are mandatory. The introduction of San Juan-Chama project water is one such new source, but it cannot be easily expanded.
       The Water Assembly's concerns about the sustainability of current water consumption in the Middle Rio Grande are totally valid.
       Bill Hume is a former policy analyst for the Bill Richardson administration with a specialty on water issues and a former editorial page editor for the Albuquerque Journal.
       

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