Is That My Groundwater or Your Surface Water?

Issue mixes law and hydrology, with mixed results.

The legal wheels continue to turn in efforts to settle the controversy about when a well is or is not pumping subflow, with a lot riding on the outcome in the Gila River adjudication.

Consider: Water use by a well owner pumping groundwater in areas outside Active Management Areas is subject to “reasonable and beneficial use.” If a legal ruling then determines the well is in fact pumping subflow, water hydrologically connected to surface water, the water is then subject to the jurisdiction of the adjudication court. A well subject to adjudication will be involved in a court process to determine the nature, extent and relative priority of its water right.

Same well, same water, but a new legal designation means the water is subject to different regulations that affect its ownership and use.

Understanding the situation requires an understanding of the workings of Arizona’s bifurcated water law; i.e. surface water and groundwater are considered separate and distinct, with each regulated differently. That groundwater and surface water actually intermingle hydrologically therefore presents a legal problem, to define at what point groundwater and surface flow interact.

In 1988, Stanley Z. Goodfarb, the then presiding judge in the Gila River adjudication, made a stab at such a definition when he adopted a 50%/90-day rule. It said groundwater is appropriable if, over a 90 day period, its removal from the underlying aquifer reduces the flow of any nearby surface supply by 50 percent or more of the total volume pumped. The Arizona Supreme Court rejected this formula as arbitrary. In 1994, Goodfarb then came up with a definition of subflow as saturated Holocene floodplain alluvium that the state Supreme Court upheld.

(The state court’s ruling eventually went to the U.S. Supreme Court when the Phelps Dodge Corp. asked the Court to review it. Attorney’s for the mining company argued that the Arizona high court greatly expanded the definition of groundwater, with the result that huge deposits of groundwater would be reclassified as subflow and therefore be appropriable as surface water. The Court let the ruling stand, refusing to hear the dispute.)

The next order of business is to determine the lateral extent of the subflow or, in other words, the actual or jurisdictional subflow zone. Wells within that zone will be presumed to be pumping subflow subject to adjudication. Further, wells located outside the designated zone, if their cone of depression enters the subflow zone, also could be determined to be pumping subflow

This is critical determination, with much at stake. Arizona Department of Water Resources attorney Jan Ronald says. “This is a issue that will ultimately determine the boundaries of the entire Gila River adjudication and is an important concern among all major parties in the adjudication.”

The essence of the issue is whether the jurisdictional subflow zone will be determined to be narrow or wide. Preferences of involved parties mostly depend upon the type of water right they now hold. For example, parties with water rights to the Verde River prefer a wide jurisdictional subflow zone. This will include a greater number of wells in the adjudication. The impact of groundwater pumping on the river flow would then likely be reduced.

On the other hand, those relying on groundwater pumping for their water supplies prefer a narrow subflow band to be drawn, with the result that many fewer wells would be brought into the adjudication. Thus the status quo would be generally maintained, with groundwater pumping still regulated according to “reasonable and beneficial use,” a situation far less threatening to groundwater pumpers than being subject to the adjudication.

Even if a well is determined to be within a subflow zone however it does not necessarily mean the well is in fact pumping subflow. Ronald explains: “The action in effect determines the number of wells to be brought into the court’s jurisdiction to be subject to further analysis as part of the court process. If your well is within the jurisdictional subflow zone there is a presumption that you are pumping subflow, not a determination.”

Ronald says the burden is then on the well owners in the subflow zone to show that their wells are not in fact pumping appropriable subflow.

DWR is now embarked on a quest to define the jurisdictional subflow zone and otherwise do the legal work to apply the Court’s subflow ruling. In a Jan. 8 hearing, Judge Ballinger chided DWR for a lack of progress and directed the agency to prepare a report on the San Pedro watershed, describing a methodology for determining the jurisdictional subflow zone as well as proposing a test for implementing the cone of depression analysis. The report is to be filed by March 29. Parties will then have 45 days to comment and provide any additional information for the court to consider.

Ronald considers this just the beginning. She says, “I think a lot more work will need to be done. The court asked DWR to use the San Pedro watershed as starting point for developing methods and procedures for implementing the test in the Arizona Supreme Court decision.”

To some critics much of this legal wrangling is beside the point, the result of flawed state water law. University of Arizona hydrologist Thomas Maddock says, “The thing about subflow is that it is not a scientific fact. It is strictly a legal entity made up because of the bifurcated water law we have in Arizona; i.e., reasonable use for groundwater and prior appropriation for surface water.”

He says, “Lots of money will be spent trying to define jurisdictional subflow zones in a high-powered, high-falutin manner, and the critical thing is the cone of depression. Whether a well is declared to be within a jurisdictional zone or not, if its cone of depression is affecting the river the well is pumping surface water. The judge should realize he does not have to spend a lot of effort defining the jurisdictional boundaries because the cone of depression will take care of that.

“But the problem is we are dealing with a non-hydrological issue that people are trying to make into a hydrological issue, and it does not work. There is no difference between water that is groundwater and surface water. And they are constantly interchanging — surface water becomes groundwater and groundwater becomes surface water”

Meanwhile the impatience of some of the major parties to the adjudication adds further pressure for working out a definition of subflow and may ultimately force the cone of depression issue. Indian tribes have been filing suits along the Gila River seeking injunctions against groundwater pumpers pumping surface flow. A political heavyweight, the Salt River Project also is an aggrieved party, its rights on the Verde River threatened. During the last six years over 3,000 wells have been installed in likely subflow zones along the Verde River. SRP is very concerned.

Also calling attention to the Arizona’s groundwater-surface water dilemma is the issue of riparian protection, which has attracted increased notice lately. Groundwater pumping is generally recognized as a prime factor in disrupting surface water flow. A lawsuit recently filed against the state by the Arizona Center for Law in the Public Interest claims that existing state law does not adequately protect water courses.

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