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IMPROVING NEW MEXICO’S WATER MANAGEMENT - page 35 / 47

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aquifer. Pumping out of the aquifer creates a deficit that the river will eventually recharge. A

major complication is that the recharge process may take decades. But the net effect is that the

river is drawn down as it replenishes the depleted aquifers. This affects downstream surface

users and compact obligations. To counteract the effect on surface flows, often the SEO will

require junior groundwater users to purchase senior surface water rights to neutralize the effect

on the river. We have not implemented this part of the law either - witness the Pecos river valley.

The state of New Mexico has been spending millions of dollars in buying or leasing water to

meet Compact obligations to Texas caused by excessive groundwater pumping. In essence the

state of New Mexico is buying out Pecos valley agriculture to ship water to Texas (just a side

note, by the time the water in the Pecos reaches the New Mexico/Texas border it is too salty to

be of any value).

A Lower Pecos Valley Regional Water Plan approved by the NM Interstate Streams

Commission in 2002 has an innovative method to meet compact obligations. Junior groundwater

irrigators in a water short year would pump out of the aquifer directly into the river enough water

to meet compact obligations. In water surplus years, the river would naturally replenish the

depleted aquifers and still satisfy compact obligations and senior water rights. The junior water

right holders would bear the cost of the program, but this would be small price considering the

alternative, a shut down of groundwater based agricultural production.

Anther conjunctive relationship between river and shallow aquifers is return flow.

Irrigators put on more water than is actually required by the crop. This is necessary even with

very efficient irrigation. The evapotranspiration process of the crops builds up salts in the root

zone. Sufficient salt buildup will reduce yields or worse kill the crop. Using leaching fractions, a

technique of putting on more water that the crop uses and leaching the salt down below the root

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