Idaho, like most western states, has long recognized in principal that the prior appropriation doctrine applies to both ground and surface water.161 Nevertheless, as a practical matter, ground water and surface waters long were managed separately. This is no longer the case. With improving scientific understanding of the physical connection between ground and surface waters, conjunctive administration has become a legal and practical reality.
First a comment on terminology. The term “conjunctive administration” refers to the administration of ground and surface water rights. Administration refers to the Department’s statutory responsibility to enforce priority, including the curtailment of junior water rights when required to meet senior needs. The term “conjunctive management” is broader. It refers to the full panoply of governmental and private efforts to reduce conflict between ground and surface water users and promote more effective utilization of all water resources. Thus, while conjunctive administration deals with the brute-force “policing” of priorities, conjunctive management includes such things as research, education, voluntary conservation measures and other demand reduction, recharge projects, provision of substitute water supplies, and other efforts to stabilize or improve water availability. This distinction in terminology, however, is fairly recent. At the time that the conjunctive management rules were adopted in 1994, the term conjunctive administration was not yet in vogue. Using current terminology, those rules would more appropriately be named the conjunctive administration rules.
Today, conjunctive administration and conjunctive management present perhaps the most complex policy issues in Idaho water administration today. Part of this complexity comes from the limited (but steadily increasing) knowledge about the hydraulic operation of the ground water resource itself and its connection to surface supplies. In the past, it was impossible to quantify how pumping a well here might affect a river there. Today sophisticated computer models are capable of predicting such impacts with remarkable precision—at least in parts of the state. Making such predictions is particularly complex because the impacts are not static. The extent and timing of these effects often are delayed, masked, or compounded by other factors, both known and unknown.162
In most cases, ground water will be “tributary” (i.e., connected) to surface streams, meaning that it will contribute to, or receive water from, surface stream flows. Localized situations do exist where the ground water is confined in such a way that it will not reach a surface stream, where its movement toward a stream is best measured in geologic time, or where the connection is geographically remote from the stretch of river where most wells or headgates are located.
As a matter of law, conjunctive administration is applicable and appropriate anywhere in the state that ground and surface water supplies are hydraulically interconnected. To date, conjunctive administration has been actively undertaken by IDWR only with respect to water rights drawing from the Eastern Snake Plain Aquifer (“ESPA”) and hydraulically connected rivers and streams. It is expected that conjunctive administration will reach other areas of the state, perhaps with the Big Wood River basin being next.
The ESPA is a highly productive ground water aquifer underlying a 10,800 square mile area stretching across southern and southeastern Idaho. (See map of the ESPA set out in Appendix G.) As the Idaho Supreme Court has
observed, “[i]t is estimated that [the ESPA] contains up to a billion acre-feet of water, which would be roughly the amount of water contained in Lake Erie.”163 The aquifer is connected to the Snake River in various places and to varying degrees.
161 This recognition is not universal. For instance, the Supreme Court of Nebraska recently confirmed that Nebraska law ignores the interrelationship of ground water and surface water. In that state, the law of prior appropriation applies only to surface water, while ground water is governed by the common law rule of reasonableness and the statutory Ground Water Management and Protection Act. Spear T. Ranch, Inc. v. Knaub, 269 Neb. 177, 691 N.W.2d 116 (2005).
162 An excellent discussion of the complexities of conjunctive management is contained in Douglas L. Grant, The Complexities of Managing Connected Surface and Ground Water Under the Appropriation Doctrine, 22 Land & Water L.Rev. 63 (1987).
163 Clear Springs Foods, Inc. v. Spackman, 150 Idaho 790, 252 P.3d 71 (2011) (this was the Idaho Supreme Court’s decision in the
“Spring Users’ delivery call,” discussed below).
The aquifer discharges to the Snake River approximately 7.5 million acre-feet annually through spring complexes located in the Thousand Springs area and near the American Falls Reservoir. It reportedly receives an average of 8 million acre-feet of recharge. In addition, the Snake River provides irrigation water to some two million acres through natural flow and some 4 million acre-feet of storage in the River’s upper reaches. Another two million acre-feet of water is pumped each year from the ESPA to serve over one million acres of farm land.
In 1994, the IDWR promulgated rules governing conjunctive administration of ground and surface waters having a common source of supply.164 The Department’s rulemaking was spurred by the decision in the case of Musser v.
Higginson.165 In Musser, the Idaho Supreme Court held that the Department’s Director had a clear legal duty to
“distribute” water to the holder of senior irrigation rights diverted from springs in the Thousand Springs area near Hagerman, Idaho.166 Because the senior’s source of water in Musser was a spring discharge from the ESPA at a point on the Snake River canyon wall, there were no junior spring or surface rights that could be curtailed to fill the calling spring right. The implication of this ruling, then, was that the Director could be required to curtail junior ground water rights withdrawing from the ESPA if the curtailment would result in more water being made available to the spring user.
The Department’s Conjunctive Management Rules establish a procedure by which senior water right holders may make a “delivery call” by petitioning the Department to administer ground and surface water rights in priority within an area of common ground water supply. These rules set out extensive criteria for determining the nature and extent of the interconnection of various water rights, for evaluating whether withdrawals by a junior ground water right will materially injure a senior water right, and for evaluating mitigation plans that might be proposed by a junior right holder who ultimately is found to be subject to the senior delivery call. The rules also provide for phased-in curtailment of ground water rights subject to a delivery call.
The Conjunctive Management Rules are applicable statewide, and apply even to delivery. So far, the Department has designated only the ESPA as an area having a common ground water supply. This area is defined by the Department by reference to the report “Hydrology and Digital Simulation of the Regional Aquifer System, Eastern Snake River Plain, Idaho” U.S. Geological Survey Professional Paper 1408-F (1992).
In the SRBA, the court has adopted a “general provision” dealing with conjunctive management that places all water users on notice that the designation of a source for their water right does not immunize them from a delivery call from a senior right holder in a separate, but connected, source.167 The court’s decision in what was designated as Basin Wide Issue 5, concluded protracted litigation among SRBA claimants concerning the manner in which the SRBA decree would address conjunctive management. In A&B Irrigation Dist.168 the Idaho Supreme Court observed that
“[c]onjunctive management of ground water and surface water rights is one of the main reasons for the commencement of
164 Rules for Conjunctive Management of Surface and Ground Water Resources (“Conjunctive Management Rules” or “CMR”), IDAPA 37.03.11, were promulgated by order of the Director on October 7, 1994. The Idaho Legislature took no action to disapprove the rules under Idaho Code § 67-5291. The Idaho Supreme Court has ruled that the Conjunctive Management Rules are constitutional on their face. American Falls Reservoir Dist. No. 2 v. IDWR, 2007 WL 677947 (Idaho).
165 Musser v. Higginson, 125 Idaho 392, 871 P.2d 809 (1994).
166 Musser v. Higginson, 125 Idaho at 395, 871 P.2d at 812.
167 In re: SRBA Case No. 39576, Memorandum Decision and Order of Partial Decree, Connected Sources General Provision (Conjunctive Management), Basinwide Issue No. 5, (Feb. 27, 2002).
168 A & B Irrigation Dist. v. Idaho Conservation League, 131 Idaho 411, 958 P.2d 568 (1998).
the Snake River Basin Adjudication.”169 The court went on to require the SRBA Court to determine the ultimate source of the ground and surface water rights being adjudicated and the relative priority between surface and ground water rights.170
The Department also has proposed in draft form additional rules of statewide applicability.171 These draft Water Management Rules are contemplated to serve as blanket rules, of which the existing Conjunctive Management Rules would be a subset. They include a process by which the Department would administer (i.e., curtail or reduce diversions or require mitigation from) junior water rights, including junior ground water rights, to prevent injury to senior ground and surface water rights. A key difference between the Conjunctive Management Rules and the proposed Water Management Rules is that, under the latter, administration of junior ground water rights would occur whenever the Department
determined that such diversions were causing injury, without the need for a senior delivery call.172
The draft Water Management Rules also propose criteria for establishing rebuttable presumptions about the depletive effects of ground water withdrawals, and about whether injury is occurring to a senior water right as a result of junior ground water withdrawals.
The draft rules thus would form an overlying framework for conjunctive administration by the Department. As water right claims have been recommended173 or decreed in the SRBA, the Department either has incorporated, or will incorporate, them into Water Districts organized pursuant to Chapter 6, Title 42 of the Idaho Code. Five new Water Districts (Water Districts 100, 110, 120, 130 and 140, encompassing much of the ESPA, have been formed by the
169 A&B Irrigation Dist., 131 Idaho at 422, 958 P.2d at 579 (quoting 1994 Interim Legislative Committee Report on the Snake River Basin Adjudication, p. 36-37).
170 A&B Irrigation Dist. v. Idaho Conservation League. Interestingly, in response to the SRBA Court’s ruling that a conjunctive management general provision was not required because the Department had adopted the Conjunctive Management Rules, the Supreme Court also held that
[the Rules] do not necessarily overlap the SRBA proceedings. They do not provide for administration of interconnected surface and ground water rights in the SRBA, nor do they deal with the
interrelationship of water rights within the various Basins defined by the Director and the SRBA district court, and they do not deal with the interrelationships of those Basins to each other and to the Snake River in the SRBA proceeding. The Rules adopted by the IDWR are primarily directed toward an instance when a “call” is made by a senior water right holder, and do not appear to deal with the rights on the basis of “prior appropriation” in the event of a call as required.
A&B Irrigation Dist. v. Idaho Conservation League. This language has confounded many. It could be read to mean simply that the Rules themselves do not determine the relative priorities of rights or the hydrologic interrelationship between those rights or between the various sources and basins, which the Court ruled were issues the SRBA was specifically commenced to conclude. Others have argued that this statement holds that the Conjunctive Management Rules violate the prior appropriation doctrine. The Idaho Supreme Court’s 2007 ruling that the Conjunctive Management Rules are constitutional on their face, however, is inconsistent with that argument. See American Falls Reservoir Dist. No. 2 v. IDWR, 2007 WL 677947 (Idaho).
171 Working Draft Text for Negotiated Rulemaking by the Idaho Dep’t of Water Resources, IDAPA Docket No. 37-0313-9701 (July 10, 2001).
172 Section 37.03.13.020.04.a of the draft rules provides:
[W]hen data gathered by the Department or otherwise submitted to the Department show to the satisfaction of the Director that the diversion of ground water under any water right, which is not included in a water district, causes injury to a senior priority surface water right or to a senior priority ground water right, such junior priority diversion shall be curtailed under the provisions of Section 42-237a.g., Idaho Code, unless approved mitigation is provided in accordance with Rule 20.13 of these rules.
173 Some water right claims have been incorporated into Water Districts on the basis of the Department’s recommendations of the claims to the SRBA before final determination and decree by the Court. The Department has sought such “interim administration” in areas where it believes it has sufficient information about the water rights and where immediate administration has been deemed necessary.
Department since 2002.174 Administration of ground water rights in these new Water Districts, including conjunctive administration, is to occur pursuant to standing instructions from the Department to the Watermasters.
B. Response to changes in aquifer levels and spring production