Justice ERICKSON
delivered the Opinion of the Court.
The Board of County Commissioners for Arapahoe County (Arapahoe County), appeals from a judgment of the District Court, Water Division 4 (water court), dismissing Arapahoe County’s applications for conditional water rights decrees in the Gunnison Basin. We affirm the water court’s dismissal of the application for a conditional water rights decree that Arapahoe County purchased from the National Energy Resources Company (ÑECO). We reverse the water court’s dismissal of Arapahoe County’s application for a conditional water rights decree based upon a failure to prove water availability, and re[957]*957mand for further proceedings consistent with this opinion or for a new trial.
The water court’s dismissal of Arapahoe County’s application for a conditional water rights decree requires us to construe section 37-92-305(9)(b), 15 C.R.S. (1990), the “can and will” statute,1 and to determine the extent to which existing conditional and absolute decrees should be considered in determining water availability. In requiring Arapahoe County to prove the availability of water to complete the project in the application for a conditional water right, the water court assumed that all major senior conditional rights will become absolute, and that holders of absolute water rights decrees will divert the maximum amount permitted under the decrees. The “can and will” statute requires an applicant for a conditional water rights decree to prove the availability of water under river conditions existing at the time of the application as a threshold requirement to establishing that there is a substantial probability that the project can and will be completed with diligence and within a reasonable time. Accordingly, we reverse and remand for further proceedings consistent with this opinion or for a new trial.
I
The conditional water rights sought in these cases are for a large water development known as the Union Park Project. The original application was by NECO in 86-CW-226 and asserted a claim for conditional water rights for the Union Park Project. The Union Park Project included construction of the Union Park Reservoir with a capacity of 900,000 acre feet on Lottis Creek, a tributary to the Taylor River. Following a hearing on a motion for summary judgment in 86-CW-226, the water court dismissed most of the application on the grounds that it was a speculative appropriation. § 37-92-103(3)(a), 15 C.R.S. (1990).
Arapahoe County acquired the rights held by NECO to develop the Union Park Project and, on December 30, 1988, filed a separate application in 88-CW-178 to preserve the claims made by NECO in 86-CW-226. On November 30, 1990, Arapahoe County filed amended applications 86-CW-226 and 88-CW-178, which included a plan for augmentation as a contingency in the event the water court found that there was insufficient unappropriated water available to permit diversion of water without injury to existing water rights, and provided for alternate points of diversion.
The Union Park Project would take water from the Upper Gunnison River Basin, located west of the Continental Divide in Gunni-son County, then move the water through a tunnel to the Antero Reservoir located east of the Continental Divide in Park County, and would finally transfer the water by a series of tunnels, pipelines, siphons, and flumes to Arapahoe County for ultimate use by its inhabitants and others who contracted with Arapahoe County for the purchase of water.
The proposed sources of water for the Union Park Project are tributaries of the Gunnison River. Within the Gunnison River Basin, the East River and the Taylor River join at the town of Almont in Gunnison County, Colorado to form the Gunnison River. The East River Basin extends over 300 square miles and the Taylor River Basin encompasses approximately 500 square miles. The Gunnison River is a tributary of the Colorado River, which it joins at the City of Grand Junction. Approximately 1.8 million acre feet of water per year flows from the Gunnison River Basin into the Colorado River.
In order to acquire the amount of water allegedly necessary for the Union Park Project, Arapahoe County relies on: six different points of diversion; eleven alternate points of diversion; use of federal reservoir storage facilities; assessment and redetermination of federal water rights; condemnation of existing water rights; change of use of conditional [958]*958water rights from nonconsumptive to consumptive uses; plans for augmentation; the possible purchase of water rights; and the reevaluation of water rights in the Gunnison River Basin based on the actual legal use of water and present constraints under interstate compacts.2
Over a five-year period, the water court considered the objections of a number of water users whose rights are senior and superior to those asserted by Arapahoe County. The water court conducted hearings and entered pretrial orders formulating the issues for trial of Arapahoe County’s applications for conditional water rights decrees and the statements in opposition filed by other water users in the Gunnison River Basin.
The water court required Arapahoe County to prove the availability of water in the Gunnison River Basin to complete the Union Park Project. After a number of pretrial hearings, the water court required that computer models be prepared to simulate future river conditions with the assumption that all water that can be diverted in the exercise of decreed senior absolute rights and major conditional" water rights be considered unavailable for appropriation.3
The water court bifurcated the trial and in phase I heard evidence to determine the availability of water for Arapahoe County’s Union Rark Project. Phase II of the trial was to determine the feasibility of the Union Park Project and other remaining issues. The water court dismissed Arapahoe County’s application for a conditional water rights decree based upon a finding that the water was not available for completion of the Union Park Project. The dismissal of Arapahoe County’s application eliminated the need for trial of the issues reserved for phase II. The water court’s dismissal of Arapahoe County’s application for a conditional water rights decree was based upon an erroneous standard for determining the availability of water.
The assumption by the water court that all major senior conditional water rights will become absolute and that holders of absolute water rights will divert to the full extent permitted under their decrees excluded water that is available for appropriation under current conditions on the river. The assumptions for the determination of water availability are contrary to experience and are improbable. A conditional water right may not be perfected and may be terminated for lack of diligence or by abandonment. § 37-92-301, 15 C.R.S. (1990 & 1994 Supp.). Absolute water rights are not in all instances exercised to the full extent or for the full time period permitted in the decree. See, e.g., Rominiecki v. McIntyre Livestock Corp., 633 P.2d 1064, 1067 (Colo.1981) (stating that “diversions are limited to an amount sufficient for the purpose for which the appropriation was made, even though such limitation may be less than the decreed rate of diversion”). To require an applicant to prove the availability of water based on the assumption that all senior conditional rights will be perfected and that all absolute rights will be utilized in their full decreed amounts is to foreclose recognition of applications for conditional water rights decrees that have every [959]*959prospect of resulting in completed appropriations within a reasonable time.
II
The water court’s Findings of Fact, Conclusions of Law, Judgment & Decree was entered on October 21, 1991. The issue in phase I of the trial was the availability of water in the Gunnison River Basin to complete the Union Park Project in accordance with Arapahoe County’s two applications and amended applications for conditional water rights decrees. The water court’s interpretation of Southeastern Colorado Water Conservancy District v. City of Florence, 688 P.2d 715 (Colo.1984), and its application of section 37-92-305(9)(b), the “can and will” statute, require reversal for further proceedings consistent with this opinion or a new trial.
To initiate an appropriation of water there must be a co-existence of an intent to appropriate and an open physical act. Northern Colorado Water Ass’n v. Three Peaks Water, Inc., 859 P.2d 836, 839 n. 2 (Colo.1993). An applicant must have an intent to put the water to beneficial use and must demonstrate his intent by an open physical act sufficient to put third parties on notice. Colorado River Conservation Dist. v. Vidler Tunnel Water Co., 197 Colo. 413, 416, 594 P.2d 566, 568. (1979).4 The right to appropriate water does not include a right to speculate as to the future use and possible sale of the water. Id., at 417, 594 P.2d at 568. We said in Vidler:
Our constitution guarantees a right to appropriate, not a right to speculate. The right to appropriate is for use, not merely for profit. As we read our constitution and statutes, they give no one the right to preempt the development potential of water for the anticipated future use of others not in privity of contract, or in any agency relationship, with the developer regarding that use. To recognize conditional decrees grounded on no interest beyond a desire to obtain water for sale would — as a practical matter — discourage those who have need and use for the water from developing it. Moreover, such a rule would encourage those with vast monetary resources to monopolize, for personal profit rather than for beneficial -use, whatever unappropriated water remains.
Id.
To prevent speculation, Vidler requires a firm contract or agency relationship with a proposed user who is committed to beneficially use the water. Id. at 417-18, 594 P.2d at 568-69. In Vidler, decided before the adoption of the “can and will” statute, we stated, “[a] showing of actual, certain availability, or of a good faith belief in the availability, of unappropriated water is not a prerequisite for an award of a conditional right to waters from surface streams.” Id. at 418, 594 P.2d at 569.
In December of 1978, four related groups of claimants filed applications for the determination of water rights to divert and use large quantities of tributary and nontri-butary ground water for speculative purposes. See State v. Southwestern Colorado Water Conservation Dist, 671 P.2d 1294, 1300 (Colo.1983); Southeastern Colorado Water Conservancy Dist. v. Huston, 197 Colo. 365, 369 n. 2, 593 P.2d 1347, 1349 n. 2 (1979). In response to the Piston case and to concerns regarding speculation in water rights, Senate Bill 481 (S.B. 481) was enacted in 1979. Ch. 346, 1979 Colo.Sess.Laws 1366. The relevant provisions of S.B. 481 are the amendment of the definition of “appropriation” 5 and the addition of the “can and will” [960]*960provision in the statute.6 By amending the definition of “appropriation” the General Assembly reaffirmed the anti-speculation holding of Vidler. See Jaeger v. Colorado [River] Ground Water Comm’n, 746 P.2d 515, 522 (Colo.1987) (“The definition of ‘appropriation’ set forth in the 1969 Act [Water Right Determination and Administration Act of 1969] expressly incorporates the anti-speculation doctrine applied in Vidler...7
The “can and -will” statute imposes limitations on applications for conditional water rights decrees and provides:
No claim for a conditional water right may be recognized or a decree therefor granted except to the extent that it is established that the waters can be and will be diverted, stored, or otherwise captured, possessed, and controlled and will be beneficially used and that the project can and will be completed with diligence and within a reasonable time.
§ 37-92-305(9)(b). The General Assembly enacted the “can and will” statute “to reduce speculation associated with conditional decrees and to increase the certainty of the administration of water rights in Colorado.” FWS Land & Cattle Co. v. State, Div. of Wildlife, 795 P.2d 837, 840 (Colo.1990). The legislative history of the “can and will” statute reflects that the purpose of the statute was to prevent speculation by denying recognition of claims for conditional water rights that have no substantial probability of maturing into completed appropriations.8
[961]*961The “can and will” statute prevents approval of an application for a conditional water right decree that cannot or will not be completed with diligence within a reasonable time. The statute goes beyond the anti-speculation doctrine of Vidler by adding the requirement that an applicant for a conditional water right decree must demonstrate that the water can and will be beneficially used. See Mark E. Hamilton, Comment, The “Can and Will” Doctrine of Colorado Revised Statute Section 87-92-305(9) (b): Changing the Nature of Conditional Water Rights in Colorado; 65 U.Colo.L.Rev. 947, 953 (1994) (hereinafter Hamilton) (stating that the “can and will” statute “moved beyond mere prohibition of speculation and created an entirely new statutory requirement for the acquisition of a conditional right.”). The enactment of the “can and will” statute would have been unnecessary if the General Assembly intended to merely codify Vidler.
The water court construed Southeastern Colorado Water Conservancy District v. City of Florence, 688 P.2d 715 (Colo.1984), as requiring Arapahoe County to assume that all major senior conditional water rights will become absolute and that holders of absolute decrees will divert the amount of water that was decreed in determining water availability. We disagree with the water court’s anal-^ ysis of Florence.
In Florence, the City of Florence (Florence) sought a conditional water right decree to divert 100 cubic feet per second (cfs) from the over-appropriated Arkansas River. The Southeastern Colorado Water Conservancy District (objector) presented evidence that only 5 to 10 cfs was needed and that construction costs to divert 100 cfs would be $2.5 million, which far exceeded Florence’s financial resources. In addition, diversions of 100 cfs would greatly exceed the 4.7 cfs capacity of Florence’s intake, pumping, treatment, and storage facilities. Id. at 716 n. 1. Evidence was presented that the decree sought would be in priority during flood conditions for one or two days every twenty-five years. Id. at 716 n. 2. Florence successfully argued that conditions on the river might change or that there might be meteorological changes that would increase water availability in the future, and was granted a conditional water right. Id. at 718.
We held that the “can and will” statute replaced the Vidler standard on proof of availability of unappropriated water and “requires proof that water will be diverted and that the project will be completed with diligence before issuance of a decree for a conditional right.” Id. The applicant in Florence failed to sustain its burden of proof that it had complied with the “can and will” statute.
The interpretation of the “can and will” statute in Florence is broader than the anti-speculation holding of Vidler. See Hamilton at 957-58. An applicant must prove that water is available for appropriation under Florence. However, Florence left unanswered the extent to which existing conditional and absolute water rights decrees should be considered in determining water availability.
In denying a conditional water right decree in Florence, we considered lack of economic capability, absence of need, present unavailability of water, and the doubtful feasibility of the project and concluded it was unlikely that the project would be completed with diligence and within a reasonable time.
The “can and will” statute should be construed to require an applicant for a conditional water right decree to establish that there is a substantial probability that within a reasonable time the facilities necessary to effect the appropriation can and will be completed with diligence, and that as a result waters will be applied to a beneficial use. Proof of such a substantial probability involves use of current information and necessarily imperfect predictions of future events and conditions.9
[962]*962The long established and legislatively recognized policy of maximum utilization of water provides guidance in construing the “can and will” statute. See, e.g., Fellhauer v. People, 167 Colo. 320, 336, 447 P.2d 986, 994 (1968) (noting that it is implicit in the Colorado Constitution that “there shall be maximum utiUzaMon of the water of this state”); § 37-92-102(l)(a), 15 C.R.S. (1990) (“It is hereby declared to be the policy of the state of Colorado ... to maximize the beneficial use of all of the waters of this state”). The policy of maximum beneficial use is derived from an understanding that the waters of Colorado are a scarce and valuable resource. State Engineer v. Castle Meadows, Inc., 856 P.2d 496, 505 (Colo.1993). The water court’s assumption that holders of absolute and major senior conditional water rights decrees will divert and appropriate to the decreed amounts projects water usage that is unrealistically high, and undermines the policy of maximum beneficial use of water.
The “can and will” statute was intended to prevent approval of a conditional water right that cannot or will not be completed with diligence and within a reasonable time. Therefore, to acquire a conditional water right decree, an applicant must establish that there is a substantial probability that within a reasonable time water can and will be appropriated and put to a beneficial use. The applicant must prove, as a threshold requirement, that water is available based upon river conditions existing at the time of the application, in priority, in sufficient quantities and on sufficiently frequent occasions, to enable the applicant to complete the appropriation with diligence and within a reasonable time. When river conditions existing at the time of the application for a conditional water right decree prevent completion of the proposed appropriation, there is no substantial probability that the project will be completed with diligence within a reasonable time. Conditional water rights under which no diversions have been made, or are being made, should not be considered, and absolute water rights should be considered to the extent of historical diversions rather than on the assumption that maximum utilization of the decreed amount is the amount used. Our construction of the “can and will” statute is in accord with our prior case law, with the intent of the General Assembly, and with the policy of maximum beneficial use of water.
Ill
A. NECO’s Application
NECO, Arapahoe County’s predecessor in interest, obtained a conditional water rights decree, in 82-CW-340,10 for the storage of 325,000 acre feet of water in the Union Park Reservoir for in-basin, non-consumptive hydro-electric power generation. On December 31, 1986, in 86-CW-226,11 NECO applied for additional conditional storage rights to enlarge the Union Park Reservoir by 575,000 acre feet to achieve the contemplated storage capacity of 900,000 acre feet. In 86-CW-226, NECO also sought to include additional non-consumptive and consumptive uses for the right it obtained in 82-CW-340. Arapahoe County acquired NECO’s interest in the Union Park Project, including its existing water rights, and Arapahoe County was sub[963]*963stituted as the applicant to change the use of NECO’s conditional storage decree and application for additional conditional water rights.
On December 29, 1988, as a result of a motion for summary judgment, the water court dismissed most of the application in 86-CW-226. The water court ruled that because NECO did not have firm contracts for use of the water at the time the application was filed, the application for consumptive use of 900,000 acre feet of water per year was speculative.12
B. Arapahoe County’s Application
On December 30, 1988, Arapahoe County filed a separate application for a conditional water right decree to store up to 900,000 acre feet of water per annum.13 Numerous issues of law were presented to the water court under C.R.C.P. 56(h).14 As a result of these pretrial motions, many of which pertained to implementation of the “can and will” statute, the water court entered pretrial orders establishing the framework within which evidence was to be presented. Included in this framework was the requirement that the parties model water availability to simulate river system conditions at the time of the application and assume that all water that can be diverted in the exercise of decreed senior absolute rights and major conditional water rights be considered unavailable for appropriation.
The trial extended over twenty-two days of evidentiary hearings. The water court took the case under advisement and entered its Findings of Fact, Conclusions of Law, Judgment & Decree on October 21, 1991. The court found that a maximum of 20,000 acre feet of unappropriated water is legally available for appropriation on an annual basis at the points of diversion claimed by Arapahoe County. The court also found that Arapahoe County had failed to satisfy its burden of proof and had not established that any additional unappropriated water is available. Arapahoe County claimed that expert testimony and the models presented established that between 125,000 and 139,500 acre feet of water was available on an annual basis.
Arapahoe County advised the water court that 20,000 acre feet of water was insufficient to justify proceeding to trial on phase II to determine the feasibility of the project. Accordingly, the water court dismissed Arapahoe County’s application on December 30, 1991, and issued its findings, conclusions, and orders as the final orders of the court. Arapahoe County appealed.
IV
Arapahoe County asserts that the water court erred in ruling that the application for a conditional water rights decree Arapahoe County purchased from NECO was speculative because NECO should have been allowed to offer evidence of its ongoing efforts to obtain commitments for the water sought in its application for a conditional decree up to and including the date of trial. The water court held that NECO had to establish that it had the requisite intent to appropriate water at the time it filed its application. We agree with the water court. An applicant must [964]*964identify the property, the committed ultimate users, and the specifics of its plan to appropriate water. The water court properly required NECO to demonstrate its intent to appropriate at the time the application was made.
A
The filing of an application in the water court to obtain a conditional water right is a claim that is analogous to a civil complaint. § 37-92-302(1), 15 C.R.S. (1990); see also William A. Hillhouse & Barbara T. Andrews, Management of the Complex Water Case, 31 Rocky Mtn.Min.L.Inst. 24-1, 24-12 (1985).
Section 37-92-305(1), 15 C.R.S. (1990), provides:
In the determination of a water right the priority date awarded shall be that date on which the appropriation was initiated if the appropriation was completed with reasonable diligence. If the appropriation was not completed with reasonable diligence following the initiation thereof, then the priority date thereof shall be that date from which the appropriation was completed with reasonable diligence.
Because the date an applicant initiated appropriation can establish priority, an applicant is required to set forth the date it contends it initiated the appropriation of water. § 37-92-302(2)(a), 15 C.R.S. (1994 Supp.) (“In the case of applications for a determination of a water right or a conditional water right, the forms shall require, among other things, a legal description of the diversion or proposed diversion, a description of the source of the water, the date of the initiation of the appropriation or proposed appropriation, the amount of water claimed, and the use or proposed use of the water.”).
For simplicity in administering water rights, the General Assembly has created a system whereby priority is initially determined based on the year the application for the water right is filed:
[T]he priority date awarded for water rights or conditional water rights adjudged and decreed on applications for a determination of the amount and priority thereof filed in such division during each calendar year shall establish the relative priority among other water rights or conditional water rights awarded on such applications filed in that calendar year; but such water rights or conditional water rights shall be junior to all water rights or conditional water rights awarded on such applications filed in any previous calendar year and shall also be junior to all priorities awarded in decrees entered prior to June 7, 1969, or decrees entered in proceedings which were pending on such date....
§ 37-92-306, 15 C.R.S. (1990)! Thus, two dates are critical in determining priority: the date the application was filed, which sets the calendar year the water right was filed and establishes priority in relation to filings in other calendar years; and the date appropriation was initiated, which establishes priority among rights applied for in the same calendar year.
In its application to increase the storage capacity of the Union Park Project to 900,000 acre feet, NECO asserted:
A. Date of initiation of appropriation: September 30, 1982 (Lottis Creek); October 15, 1982 (Taylor River); December 14, 1982 (Willow Creek) (all as decreed in 82CW340); and October 15, 1982 (Union-Antero Conduit).
B. How appropriation was initiated: The Union Park Project is an integrated hydroelectric and water project which was begun in 1982 and was partially decreed in 82CW340, and has continued with the application in 85CW96. The project has been initiated by proper field work, including staking and surveying of the location of the facilities by the agents of the applicant, which work has been ongoing and is presently continuing, and by corporate resolution.15
[965]*965If NECO could sustain its burden of proving that it had initiated appropriation in 1982, and completed the appropriation with reasonable diligence, NECO would have had priority over claims filed after 1986. As to claims filed in 1986, NECO would, on the basis of the relation-back doctrine, have had priority over claims filed after its 1982 initiation dates.
B
The water court required NECO to demonstrate that it had the requisite intent to appropriate water when its application was filed. NECO claims that it initiated appropriation in 1982 and is entitled to priority based on the date of appropriation. NECO could not support its claim that it initiated appropriation in 1982 by pointing to events that occurred years later. In asserting that it can rely on subsequent acts to prove its initial appropriation, NECO ignored the requirements of section 37-92-302(1) and the steps necessary to obtain a conditional rights decree. Acts that occurred after 1982 are not relevant to the determination of whether NECO met the requirements to obtain a conditional water rights decree at the date alleged in the pleadings.16 Although an applicant is required to plead that it initiated appropriation on a specific date and must prove that it complied with the requirements to obtain a conditional decree as of that date, a water court can hear evidence that supports the applicant’s initiation of appropriation that precedes the date the application for a conditional water right is filed.
The doctrine of maximum beneficial use of water requires courts to interpret applications for water rights to encourage development of Colorado’s water resources. See Metropolitan Suburban Water Ass’n v. Colorado River Water Conservation Dist., 148 Colo. 173, 194, 365 P.2d 273, 285 (1961) (stating that the relation-back principle should be construed and applied in a manner which would “aid and encourage, rather than to block development and early use of the water resources of the state.”). Accordingly, it is within a water court’s discretion to hear evidence that would establish whether the appropriation was initiated later than the appropriation date but prior to the application for a conditional decree.
If sufficient evidence of the initiation of appropriation prior to the filing of the application is produced, the trial court may conform the pleadings to the evidence and fix the date when appropriation was initiated as the relevant date for priority purposes. The water court permitted Arapahoe County to present evidence of its intent to appropriate water that existed prior to the date of the application for a conditional water rights decree. NECO offered evidence to prove that it entered into a contract with Parker Water and Sanitation District in Douglas County, Colorado, to sell 1,000 acre feet of water and an option to purchase an additional 2,000 acre feet prior to the application date. The contract stated:
Whereas, NECO has at present no other contracts with municipal or quasi-municipal end users of its water, and such contracts committing such purchasers to purchase some Project water are essential to avoid possible dismissal of the Application under Colorado case law... .[17]
In an order entered on October 29, 1988, dismissing with prejudice most of NECO’s application in 86-CW-226, the water court held:
NECO’s application [86-CW-226] filed December 29, 1986, claimed new water (i.e., 575,000 acre feet over and above the [966]*966325,000 acre feet it was conditionally awarded in 82-CW-340 in this Court), and it failed to properly identify committed ultimate users, except for Parker Water and Sanitation District in Douglas County, Colorado, which was committed to purchase 1,000 acre feet out of the 900,000 acre feet claimed by NECO. This contract alone is totally inadequate to meet the requisites of the anti-speculation statute.
NECO’s application in 86-CW-226 sought priority for 900,000 acre feet of water. At the date of filing, NECO had only contracted for the sale and use of 1,000 acre feet of water. NECO based its application on unsupported claims and then attempted to support the claims by obtaining contracts subsequent to the filing. The water court correctly required NECO to substantiate its assertions and refused to grant a conditional water rights decree because the application was based on future contingencies.18
The record does not support a conclusion that NECO formed the requisite intent prior to filing its application. The application was speculative when filed and the water court properly granted summary judgment, in 86-CW-226, dismissing the application Arapahoe County purchased from NECO.
V
Arapahoe County claims that water was available for the Union Park Project based on the current water usage in the Gunnison River Basin. At pretrial hearings and at trial, the water court rejected Arapahoe County’s assertions and a number of theories to support its application. In its pretrial orders the water court provided the basis for determining whether a conditional water rights decree would be granted for the Union Park Project. The decree outlines the procedures followed by the water court in determining the availability of water:
14. As a result of the pre-trial motions ..., the Court entered a number of orders which established a framework within which evidence was to be presented regarding the modelling of water availability and regarding the extent to which the Applicant would have to demonstrate compliance with permitting requirements as prerequisites to the issuance of the conditional decrees sought.
15. Because of the complexity of the issues and the lack of precedent, the Court, on the basis of certain motions for reconsideration, modified and refined some of said Orders, so that the most recent amendments to said Orders, together with the Court’s Case Management and Pretrial Orders, became the law of the case. Because of the sheer volume of data and materials bearing on the many issues in these cases, the issues were bifurcated for trial. As a result, the threshold issue of “water availability” was tried first. This Decree addresses that issue and some [967]*967closely related “permitting” issues regarding the Applicant’s legal eligibility to obtain three federal approvals which concern water availability (i.e. the impact of the need for special use permits from the United States Forest Service and the Bureau of Reclamation, and the impact of the Endangered Species Act).
16. Some of the significant holdings by the Court in its pretrial orders which were to guide counsel in their preparation for trial included the following:
a. “[T]he operative facts of the case must be determined as of April 15,1991, or earlier.” (1/8/91 Order)
b. The Applicant may not establish water availability by relying on the prospect of purchasing water or water rights owned by senior appropriators in order to eliminate the call of those rights. (9/14/90 Order, p. 12)
c. “Federal approval will be required before the Applicant can utilize Taylor Park Reservoir as a forebay to serve the Applicant’s pumping facilities.” (9/14/90 Order, p. 14)
d. The Applicant cannot premise water availability on an assumption that it can obtain federal approval to maintain Taylor Park Reservoir at a full or nearly full level or to install pumping plants in the reservoir. (9/14/90 Order, p. 15)
e. The Bureau of Reclamation cannot dispose of water in the Aspinall Unit except through a written contract. A subordination of water rights is tantamount to a disposition and therefore a formal written contract for subordination is necessary before the Applicant can premise water availability on subordination. (9/14/90 Order, p. 18) In connection with this principle, the Court also ruled on 4/4/91 that to the extent Arapahoe was relying on the Aspinall Unit for augmentation water, the plan could not be successfully pursued unless Arapahoe established its right to use Aspinall Unit water by written contract.
f. In analyzing water availability, the Court directed that the parties were to consider existing water rights, both absolute and major conditional decrees (which upon being made absolute would materially impact the Gunnison River Basin). Major conditional decrees were defined as those involving at least 10 c.f.s. for direct flow or at least 1,000 acre feet for storage rights. While the Court indicated that it expected the existing rights to be quantified based upon reasonable application and use of their decreed amounts, the Court also recognized that the parties had divergent views in modelling existing rights. Because this was a matter of first impression for this court,' it also authorized each party to present its theory of quantifying existing water rights with the understanding that the Court would base its decision on water availability on the approach which seemed to be most reasonable after the evidence was presented.
g. After entering at least two conflicting orders on how the hydropower generation rights of the Aspinall Unit should be modelled, the Court indicated that it would reconsider the issue, and enter its final ruling as a part of this Decree.
h. During the course of the pretrial proceedings in these two cases, the Court also made rulings in certain other cases which impact to some extent the issues herein. Briefly those cases are:
1) The Court’s 9/18/90 Decrees in cases 86-CW-202 and 86-CW-203 which awarded to the Upper Gunnison River Water Conservancy District a decree to refill the Taylor Park Reservoir to the extent of 106,203 acre feet with an appropriation date of August 28, 1975. (This case is now on appeal, but the Court held in its 4/11/91 Order that the decree in 86-CW-203 is “entitled to full recognition and enforcement unless reserved or modified by the Colorado Supreme Court.”)
2) The Court’s March 25, 1991, Decrees in 90-CW-92 and 90-CW-110 upholding the validity of certain private minimum instream flow decrees issued in 1975 in cases: W-1985, W-1986 and W-1991 (addressed in the order in 90-[968]*968CW-92) and W-1987 (addressed in the order in 90-CW-110).
3) The Court’s Decree issued in May 1991 in 88-CW-183 wherein it found reasonable diligence with respect to certain conditional decrees for the Upper Gunnison River Project (owned by the Colorado River Water Conservation District), but significantly, the Court canceled certain conditional decrees in said project, including decrees for the East River Canal and the Taylor River Canal.
Decree at ¶¶ 14-16, pp. 7-9.
In response to the numerous pretrial rulings, Arapahoe County and two objectors, the Crystal Creek Homeowners Association and the Colorado River Water Conservation District, produced computer models to simulate river conditions and to determine water availability. The models offered by Arapahoe County, and by those opposing the granting of the conditional right, produced widely disparate conclusions regarding water availability as a result of the differing assumptions used in preparing the computer models. The water court approved a method of modelling which assumed that holders of all major senior conditional and absolute water rights decrees would divert water to the maximum amount permitted under their decrees.19
The water court gave detailed directions for modelling water availability:20
17. Premises for Analysis of Existing Rights: As part of the law of the case, the Court informed counsel that it defined existing water rights as including all absolute decrees and “major conditional water rights” which had priority over the Applicant’s proposed project. (See the Court’s pretrial orders of April 4 and May 6, 1991, regarding existing water rights.) The Court recognized that in some ways a basin-wide analysis of water availability was a matter of first impression without statutory or ease law to provide well-defined guidelines. Thus, the Court indicated a willingness to let each party present its theory of the case regarding water availability, “... so long as the theory reflects the ‘present condition of the river’ and not some future condition of the river.” [Paragraph 4(g) of Order of 5/6/91 on Existing Rights.] However, while permitting some flexibility of approach, the Court also indicated that in the absence of persuasive evidence to the contrary it expected the parties to model water availability on the basis of the following principles:
a. The model was to reflect the impact of existing water rights senior to the priority dates claimed by Arapahoe.
b. The Court utilized April 15, 1991, as the date to determine the quantity of a given right.
c. As a general rule, the Court expected the parties to model existing senior rights on the basis of the face amount of the decrees for said rights, while taking into account the decreed purpose of the right — i.e. taking into account for example, that a direct flow irrigation right is not diverted continuously 365 days per year, but rather is [969]*969utilized only during the irrigation season (commonly from April through October), and that it is diverted only as needed to maintain a given crop. To permit reliable analysis in this regard, the Court authorized the parties to utilize historic data as a guide to the actual use of a given right. Further, the Court established the following guidelines:
1) In quantifying an absolute right, the Court recognized that the original decreed amount of an absolute right could be altered by a formal abandonment proceeding or by being re-quantified through a change proceeding or by modification by the Division Engineer pursuant to § 37-92-502(2). Thus, the April 15, 1991, date fixed the time after which such alterations could not be considered.
2) In quantifying a conditional right, the Court indicated that the parties could properly consider said right’s “contemplated draft on the stream.” And in this regard the Court indicated that accepted rules of thumb should be employed with respect to water usage based upon the amount of water decreed, but that in the absence of accepted formulas, the Court would consider expert opinion regarding the “quantity which is reasonable to satisfy the amount claimed for the decreed purpose.” (p. 3 of Order of 5/6/91 on Existing Rights.) However, in adopting this concept, the Court did not anticipate reevaluating the conditional right and reducing its decreed quantity based upon a belief that future demand for water would be less than reasonably estimated when the decree was granted.
159. In fact, the Upper Basin has not been intensively administered by the Division Engineer in the past, in part because of cooperative efforts by neighboring ranchers, and also based on agreements (such as the- 1975 Exchange Agreement regarding releases from Taylor Park Reservoir), which sought to maximize the beneficial use of scarce water resources. Further, records of historic diversions reflect only the water being diverted under absolute decrees, and modelling based on said records alone fails to reflect the impact of existing conditional rights which are being diligently developed to utilize additional water.
Decree at ¶¶ 17, 159, pp. 9-10, 61.
The water court ruled that in calculating the amount of water available, absolute water rights must be considered based on the face amount of the decree and the decreed purpose. We disagree.
To provide protection to the rights of other appropriators, limitations are read into every decree for a water right. Orr v. Arapahoe Water and Sanitation Dist., 753 P.2d 1217, 1223 (Colo.1988). One limitation is that “diversions are limited to an amount sufficient for the purpose for which the appropriation was made, even though such limitation may be less than the decreed rate of diversion.” Rominiecki v. McIntyre Livestock Corp., 633 P.2d 1064, 1067 (Colo. 1981). The holder of a water right decree cannot divert more water than can be used beneficially. Weibert v. Rothe Bros., Inc., 200 Colo. 310, 316, 618 P.2d 1367, 1371 (1980).
Absolute water right decrees should be considered to the extent of historical diversions, not to the maximum amount for the decreed purpose. Applicants should not be required to assume, contrary to historical practice, that every absolute decree for water rights will be exercised to divert the amount of water decreed. An applicant for a conditional water right decree may prove that water is available by demonstrating that historically water has been available at the time water is needed.21
[970]*970B
In quantifying the conditional right, the water court assumed that water would be diverted to the extent of the decreed purpose. The water court “did not anticipate reevaluating the conditional right and reducing its decreed quantity based upon a belief that future demand for water would be less than reasonably estimated when the decree was granted.” Decree at ¶ 17, p. 10. The water court’s analysis assumes that all major senior conditional decrees for water rights will be perfected, and that water will be diverted when no water is being diverted.22
We disagree with the water court’s analysis. A conditional water right is, “a right to perfect a water right with a certain priority upon the completion with reasonable diligence of the appropriation upon which such water right is to be based.” § 37-92-103(6), 15 C.R.S. (1990). Appropriation is defined as, “the application of a specified portion of the waters of the state to a beneficial use pursuant to the procedures prescribed by law....” § 37-92-103(3)(a).
In Qualls, Inc. v. Berryman, 789 P.2d 1095, 1098 (Colo. 1990), we said, “ ‘A conditional water right is adjudicated by a judicial decree recognizing the existence of an uncompleted application.’ ... Thus the holder of a conditional water right holds a vested right to obtain an absolute water right subject to completion of the appropriation with reasonable diligence.” (citations omitted).
The special concurrence in Qualls stated: Although a conditional water right has been termed vested, it is vested in the sense that if the appropriator diligently puts the water to beneficial use, the appropriator is entitled to a water right to the extent, and in the amount, actually put to beneficial use with a priority date of the original conditional decree.
Id. at 1103 (Erickson, J. specially concurring) (citations omitted).
A conditional water right decree does not reflect actual water usage. The extent to which a conditional decree will be perfected cannot be predicted with certainty and depends upon the completion of the requirements necessary to appropriate and put the water to a beneficial use. See, e.g., Upper Gunnison River Water Conservancy Dist. v. Board of County Comm’rs of Arapahoe, 841 P.2d 1061, 1064-65 (Colo.1992) (discussing the statutory requirement that owners or users of conditional water rights must file applications for a determination of reasonable diligence to maintain their conditional rights); Southeastern Colorado Water Conservancy Dist. v. Twin Lakes Assocs., Inc., 770 P.2d 1231, 1237-38 (Colo.1989) (discussing abandonment of water rights in general); Talco, Ltd. v. Danielson, 769 P.2d 468, 472 (Colo.1989) (noting that in order to obtain a finding of diligence an applicant must prove “an intention to use the water, coupled with concrete action amounting to diligent efforts to finalize the intended appropriation.”) (quoting Orchard Mesa Irrigation Dist. v. City & County of Denver, 182 Colo. 59, 65, 511 P.2d 25, 28 (1973)).
The water court’s interpretation of the “can and will” statute prohibits future appropriations based on unrealistically high assumptions of water utilization by holders of absolute and senior conditional water rights decrees. Applicants for new conditional water rights decrees are prevented from beneficially appropriating unused waters, and the policy of maximum beneficial use is undermined by the water court’s analysis of the “can and will” statute.
Although a conditional water rights decree may affect the calculation of the availability of water when the rights are exercised, it is [971]*971difficult to predict whether, and to what extent, the appropriation will be completed. Rather than speculate about the extent to which conditional rights will be exercised, and without the assumption that conditional rights will be exercised to the decreed amount, river conditions existing at the time of the application for a conditional water rights decree should be considered to determine water availability. Present conditions provide a more accurate representation of what water is being beneficially used and what water is available for appropriation. Conditional water rights under which diversions have not been made or none are being-made should not be considered in determining water availability.
VI
A cross appeal was filed by a local homeowners association (cross-appellant) and local, state, and national environmental groups. The cross-appellants contend that the water court erred in not considering the alleged impact the Union Park Project would have on the natural and man-made environment in the Gunnison River Basin. Specifically, the cross-appellants maintain that the Union Park Project would adversely affect fisheries and wildlife habitat, recreation, water quality, the basin’s economy including the tax base, property values and land use, and the general quality of life — factors they deem “vitally important to the public.” The limited inquiry required to determine whether to issue a conditional water rights decree in this case does not include evaluation of environmental factors.
The water court has exclusive jurisdiction over an application for a conditional water right decree. In re Application of Bubb v. Christensen, 200 Colo. 21, 25, 610 P.2d 1343, 1346 (1980). The relevant inquiry in determining whether to grant an application for a conditional water right decree is whether the applicant has completed a valid first step toward appropriation. The applicant, as a'first step, must establish there is an intent to appropriate water for beneficial use and overt acts put others on notice that a specified water right is being claimed. See, e.g., Northern Colorado Water Ass’n v. Three Peaks Water, Inc., 859 P.2d 836, 839 n. 2 (Colo.1993); City of Thornton v. City of Fort Collins, 830 P.2d 915, 924-25 (Colo.1992).
The cross-appellants contend that the first prong of this inquiry requires evaluation of environmental factors because an applicant must prove “beneficial use.” The cross-appellants assert that this phrase inherently encompasses a broad public policy of protecting the natural and man-made environment. We disagree.
The General Assembly has defined “beneficial use”:
“Beneficial use” is the use of that amount of water that is reasonable and appropriate under reasonably efficient practices to accomplish without waste the purpose for which the appropriation is lawfully made and, without limiting the generality of the foregoing, includes the im-poundment of water for recreational purposes, including fishery and wildlife. For the benefit and enjoyment of present and future generations, “beneficial use” shall also include the appropriation by the state of Colorado in the manner prescribed by law of such minimum flows between specific points or levels for and on natural streams and lakes as are required to preserve the natural environment to a reasonable degree.
§ 37-92-103(4), 15 C.R.S. (1990). In enacting this definition, the General Assembly referenced the mechanism it established to address protection of the environment — in-stream flow legislation.
In enacting instream flow legislation, the General Assembly granted the Colorado Water Conservation Board “exclusive authority” to appropriate minimum stream flows in natural streams and minimum levels for natural lakes. This legislation recognizes the need to protect the environment. See § 37-92-102(3), 15 C.R.S. (1990) (stating that the Colorado Water Conservation Board has authority “to correlate the activities of mankind with some reasonable preservation of the natural environment”). Thus, the General Assembly has established a statutory mechanism whereby the state can protect the interests that concern the cross-appellants.
[972]*972In addition, the General Assembly adopted the Colorado Water Quality Control Act in 1981, section 25-8-102(1), 11A C.R.S. (1989), which states:
[I]t is declared to be the policy of this state to prevent injury to beneficial uses made of state waters, to maximize the beneficial uses of water, and to develop waters to which Colorado and its citizens are entitled and, within this context, to achieve the maximum practical degree of water quality in the waters of the state consistent with the welfare of the state.
The Act further provides that:
No provision of this article shall be interpreted so as to supersede, abrogate, or impair rights to divert water and apply water to beneficial uses in accordance with the provision of sections 5 and 6 of article XVI of the constitution of the state of Colorado....
§ 25-8-104(1), 11A C.R.S. (1989). The Water Quality Control Act establishes that the General Assembly considered the need to protect the quality of the water of the state! but the legislation did not reach the degree of protection sought by the cross-appellants.
Although environmental factors might provide a reasonable and sound basis for altering existing law, we have previously held: “If a change in long established judicial precedent is desirable, it is a legislative and not a judicial function to make any needed change.” People v. Emmert, 198 Colo. 137, 141, 597 P.2d 1025, 1027 (1979) (quoting Smith v. People, 120 Colo. 39, 51, 206 P.2d 826, 832 (1949)).
In Southeastern Colorado Water Conservancy District v. Shelton Farms, Inc., 187 Colo. 181, 529 P.2d 1321 (1974), the holders of water rights attempted' to augment their water rights by eliminating phreatophytes— water consuming plants.23 The applicants asserted that they had salvaged water by eliminating phreatophytes and that the right to this salvaged water was not subject to the call of prior appropriators. We recognized that it was worthwhile to develop this source of water, but declared that “to create such a scheme is the work of the legislature-” Id. at 192, 529 P.2d at 1327.
Similarly, in R.J.A., Inc. v. Water Users Ass’n, 690 P.2d 823 (Colo.1984), an applicant proposed to remove peat bogs in order to reclaim water in the bogs. We held:
Whether to recognize such rights, and thus to encourage innovative ways of reducing historical consumptive uses by modifying conditions found in nature, is a question fraught with important public policy considerations. As such, the question is especially suited for resolution through the legislative process.
Id. at 828. We rejected R.J.A.’s invitation to establish a new state policy regarding preservation of the environment and said:
The General Assembly has addressed the accommodation of the policy of maximum utilization of water and the policy of preservation of natural resources, but only in a limited way. It has expressed its concern that maximum utilization of water be balanced by preservation of the natural environment “to a reasonable degree” by authorizing appropriations on behalf of the people of the state of Colorado for that latter purpose. §§ 37-92-102(3) and 103(4), 15 C.R.S. (1973)....
We have consistently recognized that the General Assembly has acted to preserve the natural environment by giving authority to the Colorado Water Conservation Board to appropriate water to maintain the natural environment, and we will not intrude into an area where legislative prerogative governs. The degree of protection afforded the environment and the mechanism to address state appropriation of water for the good of the public is the province of the General Assembly and the electorate.
Conceptually, a public interest theory is in conflict with the doctrine of prior appropriation because a water court cannot, in the absence of statutory authority, deny a legitimate appropriation based on public policy. [973]*973Arapahoe County offered evidence that it intended to divert water for municipal use; this use of water has always been deemed a beneficial use under Colorado law and is given priority over other competing beneficial uses by the General Assembly. See § 37-92-305, 15 C.R.S. (1990 & 1994 Supp.). The cross-appellants do not cite any authority that authorizes a water court to deny an application for a conditional decree because of environmental concerns, and we reject the cross-appellants’ invitation to create a complex system of common law to balance competing public interests.
VII
We affirm the water court’s dismissal of the application for a conditional water rights decree that Arapahoe County purchased from ÑECO. We reverse the water court’s dismissal of Arapahoe County’s remaining application for a conditional water rights decree and remand for further proceedings consistent with this opinion or for a new trial.
Justice MULLARKEY dissents, and Chief Justice ROVIRA and Justice SCOTT join in the dissent.
Justice SCOTT dissents.