Court Opinion

ID: 4656651
Source: CourtListenerOpinion
Date Created: 2021-02-02 18:04:37.546046+00
Date Added: 2024-06-11T08:00:59.072448
License: Public Domain

Digitally signed
                                                                                by Reporter of
                                                                                Decisions
                                                                                Reason: I attest to
                             Illinois Official Reports                          the accuracy and
                                                                                integrity of this
                                                                                document
                                     Appellate Court                            Date: 2021.02.02
                                                                                09:50:41 -06'00'

             Alliance for the Great Lakes v. Department of Natural Resources,
                                 2020 IL App (1st) 182587

Appellate Court          ALLIANCE FOR THE GREAT LAKES, NATURAL RESOURCES
Caption                  DEFENSE COUNCIL, OPENLANDS, and SIERRA CLUB,
                         Plaintiffs-Appellants, v. THE DEPARTMENT OF NATURAL
                         RESOURCES; WAYNE A. ROSENTHAL, in His Official Capacity
                         as Director of the Department of Natural Resources; and THE
                         METROPOLITAN WATER RECLAMATION DISTRICT OF
                         GREATER CHICAGO, Defendants-Appellees.

District & No.           First District, Fifth Division
                         No. 1-18-2587

Filed                    February 21, 2020

Decision Under           Appeal from the Circuit Court of Cook County, No. 17-CH-05445; the
Review                   Hon. Michael T. Mullen, Judge, presiding.

Judgment                 Affirmed.

Counsel on               Mark N. Templeton and Robert A. Weinstock, of Abrams
Appeal                   Environmental Law Clinic, of University of Chicago Law School
                         (Sara Kinter, law student), and Elbert Ettinger, both of Chicago, for
                         appellants.
                               Kwame Raoul, Attorney General, of Chicago (Jane Elinor Notz,
                               Solicitor General, and Christopher M.R. Turner, Assistant Attorney
                               General, of counsel), for appellees Department of Natural Resources
                               and Wayne A. Rosenthal.

                               Susan T. Morakalis, Ellen M. Avery, and Jorge T. Mihalopoulos, of
                               Chicago, for other appellee.

     Panel                     PRESIDING JUSTICE HOFFMAN delivered the judgment of the
                               court, with opinion.
                               Justices Rochford and Delort concurred in the judgment and opinion.

                                               OPINION

¶1        The plaintiffs, the Alliance for the Great Lakes, the Natural Resources Defense Council,
      Openlands, and the Sierra Club, filed this action for administrative review of the final order of
      the Department of Natural Resources (Department), granting a petition by the Metropolitan
      Water Reclamation District of Greater Chicago (District) to modify its permit to divert water
      from Lake Michigan under the Level of Lake Michigan Act (Act) (615 ILCS 50/1 et seq. (West
      2014)). On appeal, the plaintiffs, who were granted leave to intervene in the administrative
      proceedings, contend that the Department erred in the following two ways: (1) determining
      that the plaintiffs’ evidence of other conservation practices and their related discovery requests
      were not applicable to permit modification proceedings and (2) finding that partial compliance
      with only one water quality standard constituted a “reasonably satisfactory sanitary condition”
      under the Act. For the reasons that follow, we affirm.
¶2        The following factual recitation and procedural history is derived from the pleadings and
      the administrative record.
¶3        Illinois diverts water from Lake Michigan pursuant to a consent decree imposed by the
      United State Supreme Court (Consent Decree). See Wisconsin v. Illinois, 388 U.S. 426 (1967).
      The Consent Decree limits the amount of water Illinois may divert to 3200 cubic-feet-per-
      second (cfs). Id. at 427-28. The Consent Decree specifically allows Illinois to divert water into
      the Chicago Area Waterway System (CAWS), which consists of the Chicago and Calumet
      rivers, in order “to maintain it in a reasonably satisfactory sanitary condition.” Id. Illinois
      codified the terms of the Consent Decree in the Act, which designated the Department as the
      agency responsible for controlling and regulating the apportionment of diverted water from
      Lake Michigan. 615 ILCS 50/1.2 (West 2014). 1
¶4        In addition to the Consent Decree and the Act, Illinois is also bound by the Great Lakes-
      St. Lawrence River Basin Water Resources Compact Act (Compact) (45 ILCS 147/5 (West
      2014)), which codified an interstate agreement among the Great Lakes states and Ontario,
         1
          The Act originally designated that responsibility to the Illinois Department of Transportation
      (IDOT). For clarity, we also refer to IDOT as “the Department.”

                                                  -2-
     Canada. Relevant here, section 4.2 of the Compact requires that Illinois “develop and
     implement a [w]ater conservation and efficiency program, either voluntary or mandatory,
     within its jurisdiction based on the Party’s goals and objectives.” Id. (“Section 4.2. Water
     Conservation and Efficiency Programs.”). The Compact also commits Illinois to promoting
     “Environmentally Sound and Economically Feasible Water Conservation Measures.” Id.
     (“Section 4.2 Water Conservation and Efficiency Programs.”). The Compact defines this as,
     inter alia, “measures, methods, technologies or practices for *** reducing a Withdrawal,
     Consumptive Use or Diversion.” Id. (“Section 1.2. Definitions.”).
¶5        The District operates publicly owned treatment works that assist Illinois in managing the
     direct diversion of water from Lake Michigan into the CAWS. The CAWS is primarily used
     for conveying treated municipal wastewater, commercial navigation, and flood control and, as
     a result, has low in-stream velocities. The CAWS is also subject to the overflow from the
     combined sewer system that serves the Chicago area. Theses combined sewer overflows
     (CSOs), which send untreated wastewater into the CAWS, are designed to occur at points along
     the waterway to avoid flooding streets or residences. When CSOs occur, the influx of untreated
     wastewater into the CAWS can lead to violations of the water quality standards set by the
     Illinois Pollution Control Board (PCB) and enforced by the Illinois Environmental Protection
     Agency (IEPA). Particularly, CSOs have been a main contributor to depressed dissolved
     oxygen (DO) levels in the CAWS. As such, the District uses diverted water from Lake
     Michigan to increase the water flow, dilute the polluted water, and help the CAWS meet water
     quality standards.
¶6        Pursuant to the Act, the Department’s apportionment of diverted water is accomplished
     through a permit program set forth in the Department’s administrative rules (Rules) (17 Ill.
     Adm. Code 3730.301 et seq. (2014)), which were adopted in 1980. See 615 ILCS 50/3 (West
     2014) (“The Department *** shall devise and develop a continuing program for the
     apportionment of water to be diverted from Lake Michigan *** for domestic purposes or for
     direct diversion into the [CAWS] to maintain [it] in a reasonably satisfactory sanitary condition
     ***.”).
¶7        Relevant here are Rules 304, 307, and 310. Rule 304—entitled “Water Needs Criteria”—
     requires that the Department determine the “anticipated water needs for each applicant,” and
     instructs the Department, when making that determination, to consider, inter alia, the
     “implementation of conservation practices.” 17 Ill. Adm. Code 3730.304 (2014). Subsections
     (a) and (b) list the conservation practices that the Department must consider for “applicants”
     of each water user category. Id. § 3730.304(a), (b). Rule 307(a)—entitled “Conservation
     Practices and Other Permit Conditions”—requires that the Department “condition allocations
     within a user category upon required conservation practices for each user category as specified
     in subsections (b) and (c).” Id. § 3730.307(a). Subsection (c) mandates that the Department
     “require evidence of adoptions by the permittee of the following conservation practices as
     applicable to the particular user” and lists 10 such practices. Id. § 3730.307(c). Rule 310—
     entitled “Petitions for Modification”—allows for “[p]etitions for modification of an allocation
     permit” to be filed by a water user at any time. Id. § 3730.310(a). Subsection (b) lists the
     grounds for modification, which include a “substantial change in circumstances that results in
     a change in water needs of the entity” and changes to “standards affecting the water quality of
     the [CAWS].” Id. § 3730.310(b).

                                                 -3-
¶8         The Department initially granted the District permission to divert water from 1977 to 1980.
       Following the 1980 adoption of the Rules, the District was granted a 40-year permit to divert
       water in 1981. The District’s allotment of diverted water has been closely tied to the completion
       of its Tunnel and Reservoir Plan (TARP), which began construction in 1975 and, once
       completed, will consist of 109 miles of storm water tunnels and three reservoirs. Completing
       TARP is expected to reduce pollution in the CAWS by limiting CSOs and, therefore, reduce
       the District’s need for future diversionary water. As a result, the District’s 1980 permit
       allocated 320 cfs of water, which was set to reduce to 101 cfs when TARP was completed in
       2001. However, TARP was not completed on time, and in 2000, the District requested that the
       Department modify the permit to delay the reduction in its allocated water until 2014, the new
       completion date for TARP. The Department granted the District’s request to modify its permit,
       increasing its allocation amount to 270 cfs beginning in 2001, which would then reduce to 101
       cfs beginning in 2015.
¶9         On July 7, 2014, the District filed the instant petition with the Department, pursuant to Rule
       310 (id. § 3730.310), seeking to modify its permit to delay the reduction of its allocated water
       scheduled for 2015. The District provided the following four substantial changes in
       circumstances that supported modification of its petition: (1) TARP’s completion date was
       delayed from 2014 to 2029, (2) the Department received notification from the IEPA that
       regulatory standards affecting the water quality of the CAWS had been changed, (3) modeling
       forecasts showed that reducing the District’s diversion as planned would result in exceeding
       water quality standards, and (4) previous modeling had significantly underestimated the
       amount of diversion required to meet water quality standards. The District requested that the
       Department modify the permit to maintain diversion at 270 cfs until TARP is completed in
       2029.
¶ 10       The plaintiffs, the IEPA, and the Illinois Attorney General’s Office all sought to intervene
       in the proceedings. On December 12, 2014, the hearing officer granted their motions “[b]ased
       upon no objection by [the District].” The plaintiffs sought discovery from the District regarding
       specific conservation practices, and the District objected. Following a prehearing conference,
       the hearing officer granted the plaintiffs leave to file a motion to compel discovery and ordered
       them to file a statement of contested issues. The plaintiffs complied and filed a list of 12
       contested issues.
¶ 11       After briefing by the parties, the hearing officer determined that 10 of the plaintiffs’ 12
       contested issues were not appropriately available to be contested in the proceeding. Relevant
       here, the hearing officer noted that eight of the plaintiffs’ contested issues “suggest
       investigating and presumably requiring different actions to reduce the need for the requested
       diversion increase,” which the plaintiffs argued was required by Rule 304 and section 5 of the
       Act. The proposed actions the plaintiffs sought included the same conservation practices
       referenced in their discovery requests. The hearing officer concluded that both Rule 304 and
       section 5 of the Act, by their plain language, apply only to new permit applications, not permit
       modifications, and that Rule 310 provides the procedural and substantive requirements
       governing permit modifications. In support, the hearing officer noted that Rule 304 and section
       5 both used the terms “applicants” and “applications,” whereas Rule 310 used the term
       “permits.” The hearing officer further noted that Rule 310, which explicitly incorporates the
       Rules outlining the procedural requirements for permit applications, does not similarly
       incorporate any of the substantive application requirements, such as Rule 304. Additionally,

                                                   -4-
       the hearing officer noted that the District’s 2000 permit modification stated that “[i]f
       circumstances such as [delay in] the completion of TARP or problems with significant
       exceedances of water quality standards occur, a proceeding for modification may need to
       occur.” The hearing officer interpreted this provision as allowing for a delay in the District’s
       reduction to 101 cfs should the assumptions regarding TARP’s completion prove incorrect. As
       a result of this language, the hearing officer “decline[d] to regulate in a manner that would
       negatively impact legitimate reliance by a permittee on the conditions of a Department permit.”
       The hearing officer, therefore, concluded that the plaintiffs’ contested issues regarding specific
       conservation practices were not “appropriately available to be contested” in the proceeding.
       Based on this determination, the hearing officer also denied the plaintiffs’ motion to compel
       discovery regarding those same conservation practices.
¶ 12       The parties submitted position statements, and the plaintiffs also submitted a prehearing
       memorandum. The District filed written testimony of three witnesses, the plaintiffs filed
       written testimony of four witnesses, the IEPA and the Department each filed the written
       testimony of one witness. The four witnesses for the plaintiffs submitted written testimony
       recommending the study and implementation of the same conservation measures outlined in
       their contested issues. The District filed a motion to quash the plaintiffs’ prehearing
       memorandum and to strike the written testimony of the plaintiffs’ witnesses. On September
       25, 2015, the hearing officer denied the District’s motion and admitted the plaintiff’s
       prehearing memorandum and the written testimony of their witnesses for the limited purpose
       of an offer of proof regarding the prior determination that the plaintiffs’ contested issues were
       not appropriately available to be contested in the proceeding.
¶ 13       The hearing took place on October 6 and 7, 2015. Five witnesses—Dr. Charles Melching
       (the District), Jennifer Wasik (the District), Edward Saudacher (the District), Daniel Injerd (the
       Department), and Scott Twait (IEPA)—testified in person, only for the purposes of cross-
       examination. All five witnesses offered testimony in support of the District’s petition for
       modification. The plaintiffs did not present any witnesses for live testimony, but they did cross-
       examine witnesses.
¶ 14       Dr. Charles Melching testified that, at the District’s request, he created a computer model
       demonstrating that a reduction from 270 cfs to 101 cfs, prior to the completion of certain
       segments of TARP, would result in a nearly 30% drop in system-wide compliance with PCB’s
       DO standards for the CAWS. Dr. Melching testified that the DO regulatory standard has
       historically been used by the Department as the primary indicator for water quality in the
       CAWS. According to Dr. Melching’s model, a reduction from 270 cfs to 101 cfs would result
       in system-wide compliance falling from its current 95.8% to 66.8%.
¶ 15       Injerd, the Department’s director of water resources, testified that the Department agreed
       with using the PCB’s DO standard because it is the “best indicator of water quality to evaluate
       the need for and quantity of discretionary diversion water.” He further testified that the
       Department supported an allocation amount that maintained the CAWS at its current
       compliance rate as to the DO standard. Injerd stated that the Department supported the
       District’s intention to develop guidance for the “optimal use of Discretionary Diversion” and
       recommended that “this project be included as a condition” in the District’s modified petition.
       Injerd testified that the Department supported a diversion amount of 270 cfs from 2015 to
       2017, at which time the amount would reduce to 220 cfs until 2030.

                                                   -5-
¶ 16       Twait, an engineer in the water quality standards section of the IEPA, similarly testified
       that the IEPA supported increasing the District’s allocation of water to 270 cfs because that
       “will maintain the highest frequency of compliance with [DO] standards.” Twait further
       testified that the IEPA supported using the DO standard for determining “compliance here.”
¶ 17       On September 22, 2016, the Department issued an order granting the District’s petition to
       modify its allocation amount. In the written order, the Department first determined that the
       District had established, pursuant to Rule 310(b) (id. § 3730.310(b)), a substantial change in
       circumstances that supported a modification of its allocated water amount. Specifically, the
       Department noted the delay in completing TARP, the forthcoming changes to the PCB’s DO
       standard for the CAWS, and Dr. Melching’s modeling that showed a failure to increase the
       water amount would result in exceedances of water quality standards. Having so concluded,
       the Department then addressed the appropriate modified diversion amounts and the permit
       terms and conditions.
¶ 18       The Department concluded that the PCB’s DO standard was the best indicator of water
       quality for the purposes of evaluating the need for, and quantity of, discretionary diversion
       water. The Department noted that the District, the IEPA, and its own employee supported using
       the DO regulatory standard to assess water quality in the CAWS and also supported an
       allocation amount that maintained the current compliance rate at the time of the proceeding,
       which was 95%. The Department further noted that the plaintiffs made no objections to any of
       the witnesses’ ” qualifications or ability to render an opinion on this issue,” nor did the
       plaintiffs offer any “witness testimony providing the substance of an alternate position.”
       Accordingly, the Department determined that compliance with DO regulatory standards at a
       95% compliance rate was an appropriate standard for determining the water amount necessary
       “for purposes of this proceeding.”
¶ 19       Lastly, the Department addressed what, if any, conservation practices should be required
       of the District as a condition of their permit modification. The Department concluded that Rule
       307 exclusively governed this issue. The Department noted that, in its first water allocation
       decision after promulgating the Rules, it stated that Rule 307’s predecessor was the
       Department’s response to section 5’s mandate that “all feasible means reasonably available
       *** shall be employed to conserve and manage the water resources of the region.” 615 ILCS
       50/5 (West 2014). After reviewing the history of the Act and the Rules, the Department found
       that its consistent interpretation has been that the Rules codified the “Permit Condition
       Approach” when requiring conservation practices. The Department explained that, under this
       approach, each permit, whether an initial application or a permit modification, must impose as
       a condition only the conservation practices specified in Rule 307. In support, the Department
       noted that, in its first water allocation decision after the Rules were promulgated, the permit
       order contained only a provision requiring that “[e]ach permittee *** shall comply with the
       requirements of [Rule 307].” The Department highlighted the success of this longstanding
       approach to conservation by noting that the Department had already achieved a reduction in
       the District’s allocation of water from 320 cfs to 270 cfs. The Department further noted that
       the record established the District is already implementing several conservation practices that
       will help reduce its need for diverted water. Accordingly, the Department included the
       following language in the District’s modified permit: “[The District] will complete all water
       conservation practices mandated by [Rule 307].”

                                                  -6-
¶ 20       In so holding, the Department incorporated the hearing officer’s interpretation of Rules
       304 and 310 and rejected the plaintiffs’ argument that the Act and the Rules require that it
       conduct a Rule 304 water needs analysis and make a case by case determination of what
       conservation practices to require as a condition of water allocation. The Department concluded
       that Rule 310, which governs modifications to an existing permit, by its plain language,
       “focuses on the basis for modification,” such as “changes in circumstances and changes in
       information to that originally submitted in a permittee’s application for permit,” and on “the
       appropriate modification as a result of said basis.” As such, Rule 310 does not require the
       Department to replicate the substantive requirements of the permit application process, such
       as a Rule 304 water needs analysis.
¶ 21       Ultimately, the Department ordered the District’s petition modified to reflect the following
       allocation amounts: 270 cfs through 2017, 220 cfs through 2030, 101 cfs from 2031 to 2035.
¶ 22       The plaintiffs filed a motion to reconsider the Department’s decision, arguing, inter alia,
       that the Department failed to address their argument that the Compact imposed distinct legal
       requirements in addition to the Act and was, therefore, applicable to the permit modification
       proceeding.
¶ 23       On March 14, 2017, the Department issued a written order, denying the plaintiffs’ motion
       to reconsider. Relevant here, the Department agreed that section 4.2 of the Compact was
       relevant to the modification proceeding. However, the Department emphasized that the plain
       language of section 4.2 “only makes a water conservation program applicable to Illinois’s Lake
       Michigan water use” and, thus, there was no requirement to “specifically cite or mention the
       Compact” during the proceeding. Moreover, the Department concluded that “[t]he
       Department’s legally binding regulatory program set forth in [the Rules] clearly meets” the
       Compact’s requirement that Illinois create a voluntary or mandatory water conservation
       program. Accordingly, the Director denied the plaintiffs’ motion to reconsider.
¶ 24       On April 14, 2017, the plaintiffs filed a complaint for administrative review in the circuit
       court of Cook County, naming the District, the Department, and the Department’s Director,
       Wayne A. Rosenthal, as the defendants. The plaintiffs’ four-count complaint alleged the
       following: (1) the Department violated state and federal law by failing to meet its obligations
       under the Compact, (2) the Department misinterpreted Rule 304 as being inapplicable to
       petition modification proceedings, (3) the Department misinterpreted Rule 307 when it
       determined that it need not condition the District’s permit to require the implementation of
       specific conservation practices, and (4) the Department misinterpreted the Act and the Rules
       in determining that “reasonably satisfactory sanitary condition” and “water quality standards”
       are satisfied by partial compliance with DO regulatory standards.
¶ 25       On October 5, 2017, the District filed a combined motion to dismiss the plaintiffs’
       complaint pursuant to section 2-619.1 of the Code of Civil Procedure (Code) (735 ILCS 5/2-
       619.1 (West 2016)). The District argued that, pursuant to section 2-619(a)(9) of the Code, the
       plaintiffs lacked standing to appeal the Department’s modification of the District’s permit. The
       District also argued that the plaintiffs’ complaint should be dismissed pursuant to section 2-
       615 of the Code for failing to allege sufficient facts to establish their standing.
¶ 26       On January 8, 2018, the circuit court granted, without prejudice, the District’s motion to
       dismiss pursuant to section 2-615 of the Code and denied, as moot, the District’s motion to
       dismiss pursuant to section 2-619 of the Code.

                                                  -7-
¶ 27        On February 5, 2018, the plaintiffs filed an amended complaint, which included a section
       that addressed their standing. The District and the Department adopted the administrative
       record as their answer to the plaintiffs’ amended complaint.
¶ 28        The plaintiffs, the District, and the Department each filed cross-motions for summary
       judgment. The District and the Department both argued that the Department correctly
       interpreted the Rules when it granted the District’s petition to modify its permit. The District
       also renewed their argument that the plaintiffs lacked standing to bring their claims. On
       November 13, 2018, the circuit court, in an oral pronouncement, denied the plaintiffs’ motion
       for summary judgment, denied the District’s motion for summary judgment as to the standing
       issue, and granted summary judgment in favor of the District and the Department on all four
       of the plaintiffs’ claims. This appeal followed.
¶ 29        On appeal, the plaintiffs argue that the Department erred in the following two ways:
       (1) determining that the plaintiffs’ evidence of other conservation practices and their related
       discovery requests were not applicable to permit modification proceedings and (2) finding that
       partial compliance with the DO standard constituted a “reasonably satisfactory sanitary
       condition.”
¶ 30        At the outset, we must first address the District’s argument that the plaintiffs lack standing
       to bring this appeal.
¶ 31        To begin, we note that the District did not raise the standing argument before the
       Department when the plaintiffs sought to intervene. According to the December 12, 2014
       order, the hearing officer allowed the plaintiffs to intervene “[b]ased upon no objection by the
       [District].” In Illinois, lack of standing is an affirmative defense and will be waived if not raised
       in a timely fashion. Greer v. Illinois Housing Development Authority, 122 Ill. 2d 462, 508
       (1988). Therefore, the District has arguably forfeited review of this issue. Forfeiture aside, we
       nevertheless conclude that the plaintiffs do have standing to bring this action.
¶ 32        Standing requires an “injury in fact,” whether actual or threatened, that is “(1) distinct and
       palpable; (2) fairly traceable to the defendant’s actions; and (3) substantially likely to be
       prevented or redressed by the grant of the requested relief.” Glisson v. City of Marion, 188 Ill.
       2d 211, 221 (1999). A distinct and palpable injury refers to an injury that cannot be
       characterized as “a generalized grievance common to all members of the public.” Greer, 122
       Ill. 2d at 494. However, article XI of the Illinois Constitution broadens the law of standing by
       eliminating the traditional special injury requirement in an environmental action. Ill. Const.
       1970, art. XI, §§ 1-2; see Glisson, 188 Ill. 2d at 228. In Illinois, “[t]he doctrine of standing is
       designed to preclude persons having no interest in a controversy from bringing suit, but it
       should not be an obstacle to the litigation of a valid claim.” People v. $1,124,905 U.S. Currency
       & One Chevrolet Astro Van, 177 Ill. 2d 314, 330 (1997). To that end, our supreme court has
       recognized that Illinois standing law is more liberal than federal law and that “State courts are
       generally more willing than Federal courts to recognize standing on the part of any plaintiff
       who shows that he is in fact aggrieved by an administrative decision.” Greer, 122 Ill. 2d at
       491.
¶ 33        The plaintiffs argue that they have met the standing requirements because either they, or
       their members, own shorefront property on Lake Michigan and use and enjoy both the CAWS
       and Lake Michigan. They argue that these interests are harmed by the Department’s decision
       to modify the District’s permit to increase its water allocation in the followings ways:
       (1) increasing water diversion into the CAWS by an additional 420 billion gallons impacts the

                                                     -8-
       water level in Lake Michigan, which diminishes the value of lakefront property and the ability
       to recreate in Lake Michigan; (2) an increase in water diversions into the CAWS also increases
       the likelihood of an invasive species transfer, such as Asian Carp; and (3) an ineffective
       program to maintain water quality in the CAWS impacts the plaintiffs’ members’ ability to
       recreate in the CAWS. We agree.
¶ 34        Put simply, the District sought to increase its allocation of water from Lake Michigan by
       approximately 420 billion gallons for the purposes of maintaining water quality in the CAWS.
       The plaintiffs alleged sufficient facts to establish that such an increase would injure their
       members by lowering water levels in Lake Michigan, increasing the likelihood of invasive
       species migrating into Lake Michigan, and failing to address unsanitary conditions in the
       CAWS. The plaintiffs further alleged that these harms could have been redressed if the
       Department had required that the District implement the plaintiffs’ specific conservation
       practices as a condition of their allocation because these practices would reduce CSO events
       and, therefore, reduce the need for diverted water. Moreover, the Department allowed the
       plaintiffs to intervene below, without the District objecting, and afforded it the chance to cross-
       examine witnesses, submit evidence, and make applications for reconsideration. “[T]o allow
       an intervenor the status of party and to accord it all the panoplies of the adversary process but
       to deny it the statutory right of appeal requires a great leap of the imagination to satisfy the
       fundamentals of simple fairness.” Illinois Telephone Ass’n v. Illinois Commerce Comm’n, 67
       Ill. 2d 15, 23 (1977). Accordingly, we conclude that the plaintiffs have alleged sufficient facts
       to establish that they have standing to prosecute this appeal.
¶ 35        Turning to the merits, the plaintiffs first contend that the Department erred when it
       determined that their evidence of specific conservation practices was not relevant to the
       District’s permit modification proceeding. The plaintiffs contend that their evidence was
       relevant for the purposes of determining the District’s anticipated water needs pursuant to Rule
       304 and for drafting the appropriate conditions for the District’s permit pursuant to Rule 307.
       Essentially, the plaintiffs argue that the Department interpreted these Rules in such a way that
       contravenes the plain language of the Rules, the Act, and the Compact. The plaintiffs further
       contend that, due to the Department’s erroneous interpretation of their Rules, it also abused its
       discretion when it denied the plaintiffs’ discovery requests and limited their ability to introduce
       evidence.
¶ 36        In administrative review cases, we review the decision of the administrative agency, not
       the decision of the circuit court. Exelon Corp. v. Department of Revenue, 234 Ill. 2d 266, 272
       (2009). “[T]he applicable standard of review depends upon whether the question presented is
       one of fact, one of law, or a mixed question of fact and law.” (Internal quotation marks
       omitted.) Cinkus v. Village of Stickney Municipal Officers Electoral Board, 228 Ill. 2d 200,
       210 (2008).
¶ 37        The proper construction of a statute and the regulations thereunder are questions of law
       reviewed de novo. People ex rel. Madigan v. Illinois Commerce Comm’n, 231 Ill. 2d 370, 380
       (2008). “In construing regulations promulgated by an administrative agency, the same rules
       used to interpret statutes apply.” LaBelle v. State Employees Retirement System of Illinois, 265
       Ill. App. 3d 733, 736 (1994). “One of the primary rules of statutory construction is that the
       court should first consider the language of the provision at issue, and, where that language is
       clear, it should be given effect without resorting to other aids for construction.” Id. That said,
       an agency’s interpretation of an ambiguous provision in its enabling statute or its regulations

                                                    -9-
       is entitled to “substantial weight and deference” as an informed source based upon its
       “experience and expertise” to ascertain legislative and regulatory intent. Abrahamson v. Illinois
       Department of Professional Regulation, 153 Ill. 2d 76, 98 (1992).
¶ 38       An administrative agency’s decision “regarding the conduct of its hearing and the
       introduction of evidence is properly governed by an abuse of discretion standard.” Wilson v.
       Department of Professional Regulation, 344 Ill. App. 3d 897, 907 (2003). “An abuse of
       discretion occurs when no reasonable person would take the view adopted by the court.”
       Trettenero v. Police Pension Fund, 333 Ill. App. 3d 792, 801 (2002).
¶ 39       We turn first to the Department’s interpretation of Rule 304, which is entitled “Water
       Needs Criteria” and states as follows:
                    “The Department will determine anticipated water needs for each applicant. The
               Department will take into consideration in making that determination the population of
               the area to be served, projected population growth, current and projected per capita
               consumption within the area, the nature and extent of industrial uses ***, municipal
               and hydrant uses ***, implementation of conservation practices, and the reduction of
               non-revenue water as required by this Section.” 17 Ill. Adm. Code 3730.304 (2014).
       The Rule goes on to list the conservation practices that “will be considered with respect to
       applicants” in each of the specific user categories. Id. Rule 304(b) states that, for users such as
       the District, the “[c]onservation practices that will be considered” include
               “improved and more accurate measurement and accounting procedures, improved
               treatment of all wastewater flows, elimination of untreated combined sewer bypass
               flows, reasonable use of aeration facilities, implementation of navigational and storm
               response operations, and procedures to minimize Lake Michigan diversion and
               implementation of effective programs of leak prevention, detection and correction.” Id.
               § 3730.304(b).
¶ 40       The plaintiffs contend that Rule 304’s water needs analysis is applicable to each allocation
       of water, not just for new diversion applicants. As such, the plaintiffs argue that the Department
       was required to consider evidence of the specific conservation practices listed in Rule 304(b)
       relevant to a user such as the District. The Department responds that Rule 304 is only
       applicable to initial permit applications, not modifications of existing permits. The Department
       maintains that Rule 310, and the Rules incorporated therein, is the only provision applicable
       to determining whether to modify an existing user’s permit, and Rule 310 does not incorporate
       Rule 304.
¶ 41       By its plain language, Rule 304 requires the Department to determine the water needs of
       “each applicant,” which supports the Department’s interpretation that Rule 304 is only
       applicable to an initial application for diverted water. However, as the plaintiffs correctly point
       out, Rule 304(a) also refers to “permittee[s]” and “users,” which arguably supports their
       interpretation that Rule 304 is applicable to all allocations of water. Therefore, the Rules are,
       at best, ambiguous regarding whether Rule 304 is applicable to modifications of an existing
       permit. As mentioned, an agency’s interpretation of an ambiguous provision in its enabling
       statute or its regulations is entitled to “substantial weight and deference” as an informed source
       based upon its “experience and expertise” to ascertain legislative and regulatory intent.
       Abrahamson, 153 Ill. 2d at 98. Consequently, we conclude that the Department did not err in
       interpreting Rule 304’s water needs analysis as applying only to initial applications, not to
       permit modifications.

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¶ 42       The plaintiffs further contend that, if Rule 304 is read as being inapplicable to modifying
       exiting permits, then Rule 304(b), which outlines the conservation practices to be considered
       when determining the anticipated water needs of diversion water users, such as the District, is
       superfluous. Bonaguro v. County Officers Electoral Board, 158 Ill. 2d 391, 397 (1994)
       (“Statutes should be construed, if possible, so that no term is rendered superfluous or
       meaningless.”). At the center of the plaintiffs’ argument is that, since the District is the only
       entity that meets the definition of a diversionary user under Rule 303, and its permit predates
       the adoption of the Rules, then no diversion water user will ever be subject to a water needs
       analysis under Rule 304(b). The Department responds that the plaintiffs’ argument fails
       because it assumes that there will never be another entity tasked with managing the diversion
       of water into the CAWS. We agree with the Department. Although the District is the only
       entity that currently falls within that category, this does not preclude a future entity from taking
       on those responsibilities and applying for a new allocation. Therefore, nothing about the
       Department’s interpretation renders Rule 304(b) superfluous.
¶ 43       The plaintiffs nevertheless contend that Rule 310 also supports its reading of Rule 304.
       Rule 310, which is titled “Petitions for Modification,” states that
               “[p]etitions for modification of an allocation permit may be filed by any entity at any
               time. *** If the Department finds that any such petition is supported by an adequate
               statement of reasons, is not plainly devoid of merit or frivolous, and does not deal with
               a subject on which a hearing has been held within the preceding six months, a hearing
               shall be held pursuant to Sections 3730.201 through 3730.215.” 17 Ill. Adm. Code
               3730.310(a) (2014).
       Rule 310(b) then lists four possible bases for modifying an allocation permit, one of which is
       “[e]vidence of a substantial change in circumstances that results in a change in water needs of
       the entity.” Id. § 3730.310(b)(1).
¶ 44       The plaintiffs maintain that the reference to “change in water needs” contemplates a full
       water needs analysis pursuant to Rule 304. The Department responds that nothing in Rule 310
       explicitly incorporates the substantive requirements of Rule 304. We agree with the
       Department. Although Rule 310 does use the phrase “water needs,” the Rule does not
       incorporate or refer to Rule 304. In its other provisions, Rule 310 explicitly incorporates the
       procedural and substantive provisions relevant to permit applications that it wishes to duplicate
       during the permit modification process. Id. § 3730.310(a) (“Petitions for modification must
       comply with Section 3730.204(c). *** [A] hearing shall be held pursuant to Sections 3730.201
       through 3730.215.”). We, therefore, conclude that the Department did not err in determining
       that Rule 310 did not require a water needs analysis pursuant to Rule 304.
¶ 45       The plaintiffs next contend that the Department’s interpretation of Rule 304 contravenes
       the text and purpose of the Act. In support, the plaintiffs refer to the following language
       contained in section 5 of the Act:
                    “The Department in determining each allocation of water under this Act shall
               consider the water requirements of the Northeastern Illinois Metropolitan Region ***;
               the Department shall be guided by population, business and economic projections and
               requirements. The Department shall require that all feasible means reasonably available
               *** shall be employed to conserve and manage the water resources of the region and
               the use of water therein in accordance with the best modern scientific knowledge and
               engineering practice.” 615 ILCS 50/5 (West 2014).

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       The plaintiffs’ argument rests on the phrases “each allocation of water under this Act” and “all
       feasible means reasonably available *** to conserve and manage the water resources,” which
       they contend requires the Department to conduct a full water needs analysis for both new
       applications and permit modifications. See id. The Department responds that section 5 does
       not mandate that the Department consider conservation practices when determining “each
       allocation of water.” Id. Rather, section 5’s sole reference to conserving water occurs in a
       separate sentence and directs only that the Department “require” all feasible and reasonably
       available means to conserve and manage water. Id. The Department, therefore, maintains that
       nothing in section 5 supports the plaintiffs’ argument that the Act requires the Department to
       consider a permittee’s water conservation practices to determine its modified water allocation.
       We agree with the Department.
¶ 46       By its plain language, section 5 states what the Department must consider when
       determining “each allocation of water” and conservation practices are not listed. Section 5’s
       mandate that the Department require “all feasible means reasonably available” be “employed
       to conserve and manage the water resources of the region” is a separate command from a
       separate sentence. Accordingly, the Department’s interpretation of Rule 304 does not
       contravene the text of the Act because section 5 does not require the Department to consider
       conservation practices when determining “each allocation of water.”
¶ 47       The plaintiffs also contend that the Department’s interpretation of Rule 304 contravenes
       the purposes of the Compact, which they argue imposes obligations on Illinois to consider
       alternative conservation measures when determining a user’s water needs. Section 4.2 of the
       Compact requires that Illinois “develop and implement a [w]ater conservation and efficiency
       program, either voluntary or mandatory, within its jurisdiction based on the Party’s goals and
       objectives.” 45 ILCS 147/5 (West 2014) (“Section 4.2. Water Conservation and Efficiency
       Programs.”). The Compact also commits Illinois to promoting “Environmentally Sound and
       Economically Feasible Water Conservation Measures.” Id. (“Section 4.2. Water Conservation
       and Efficiency Programs.”). Section 1.2 of the Compact defines “Environmentally Sound and
       Economically Feasible Water Conservation Measures” as
               “those measures, methods, technologies or practices for efficient water use and for
               reduction of water loss and waste or for reducing a Withdrawal, Consumptive Use or
               Diversion that (i) are environmentally sound, (ii) reflect best practices applicable to the
               water use sector, (iii) are technically feasible and available, (iv) are economically
               feasible and cost effective based on an analysis that considers direct and avoided
               economic and environmental costs and (v) consider the particular facilities and
               processes involved, taking into account the environmental impact, age of equipment
               and facilities involved, the processes employed, energy impacts and other appropriate
               factors.” Id. (“Section 1.2. Definitions.”).
¶ 48       The plaintiffs cite to the provision in the Compact that commits Illinois to promoting
       “measures, methods, technologies or practices for *** reducing a Withdrawal, Consumptive
       Use or Diversion” as support for its contention that the Department’s interpretation of Rule
       304 contravenes the purpose of the Compact. Id. (“Section 1.2. Definitions.”) The Department
       responds that the Rules do satisfy Illinois’s obligations under the Compact because the Rules
       require a consideration of conservation practices when determining each application for
       diverted water and each permit features a condition requiring the permittee to implement
       certain conservation practices. We agree with the Department.

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¶ 49       Put simply, the Compact commits Illinois to promoting general conservation practices,
       which Illinois does through the Department and its Rules. The Compact does not speak,
       however, to how Illinois should approach determining allocations for new applicants as
       opposed to existing permittees. As such, the Department’s interpretation of Rule 304 does not
       contravene any provisions of the Compact, and the plaintiffs’ argument is, therefore,
       unavailing.
¶ 50       The plaintiffs’ final contention in support of their Rule 304 interpretation is that a
       Department employee made comments during the 2014 rule amendment process that suggested
       the Department would consider the conservation practices listed in Rule 304 during a future
       modification hearing. The plaintiffs offer no authority to support their position that comments
       made by an agency employee during rulemaking constitutes a persuasive aid to interpret an
       agency’s regulation. To the contrary, when confronted with an ambiguous rule or statute, we
       defer to an agency’s interpretation of its regulations made in formal proceedings, not to the
       views otherwise expressed by its staff. See McHenry County Defenders, Inc. v. City of
       Harvard, 384 Ill. App. 3d 265, 279 (2008) (finding that deference to an administrative agency’s
       interpretation occurs “in the context of specific administrative decisions [citation] and is not
       based on one employee’s deposition testimony”). We will not depart from that practice here.
¶ 51       Accordingly, we conclude that the Department did not err when it determined that it need
       not consider the conservation practices listed in Rule 304 during proceedings to modify an
       existing permit. The language in Rule 304 is, at best, ambiguous, and we therefore defer to the
       reasonable interpretation of the Department. Abrahamson, 153 Ill. 2d at 98.
¶ 52       We turn next to the Department’s interpretation of Rule 307. Rule 307—titled
       “Conservation Practices and Other Permit Conditions”—states that
               “[t]he Department shall condition allocations within a user category upon required
               conservation practices for each user category as specified in subsections (b) and (c).
               Failure by any permittee to meet the conservation requirements applicable to it within
               a reasonable period of time will, upon notice, hearing and determination of the failure,
               constitutes a violation of a Department order.” 17 Ill. Adm. Code 3730.307(a) (2014).
       While subsection (b) is not relevant here, subsection (c) states that “[t]he Department shall
       require evidence of adoptions by the permittee of the following conservation practices as
       applicable to the particular user” and lists 10 specific conservation practices. Id. § 3730.307(c).
       The parties agree that one of those 10 conservation practices—Rule 307(c)(10)—is applicable
       to the District, and it requires “[i]nstallation *** and implementation of programs to reduce to
       a reasonable minimum, and to accurately account for, water used for navigational and
       discretionary *** purposes.” Id. § 3730.307(c)(10). The Department interpreted Rule 307 as
       providing the exclusive list of conservation practices that it could require a permittee to adopt
       as a condition of their permit. As a result, the Department determined that it need not consider
       the plaintiffs’ proffered conservation practices and ordered the District to “complete all water
       conservation practices mandated by [Rule] 307.”
¶ 53       The plaintiffs challenge both the Department’s determination that Rule 307 provides the
       exclusive list of conservation practices that the Department can require of a permittee and their
       determination that a general condition requiring compliance with Rule 307 is sufficient.
       Specifically, the plaintiffs argue that the phrase “as applicable to the particular user” in Rule
       307(c) would be superfluous under the Department’s interpretation. The Department responds
       that the phrase “as applicable to the particular user” in subsection (c) is not superfluous but

                                                   - 13 -
       merely acknowledges that not all of the 10 listed conservation practices are applicable to all
       possible category of users and that only those conservation practices applicable to a particular
       category of user are required.
¶ 54       By its plain language, subsection (a) mandates only that the Department impose permit
       conditions that require the conservation practices “for each user category” specified in
       subsections (b) and (c). Nothing in the Rules allows the Department to impose conditions on
       permits requiring conservation practices not listed in subsections (b) or (c). Consequently, the
       Department did not err when it determined that Rule 307 provided the exclusive list of
       conservation practices that it could require as a condition in the District’s modified permit.
¶ 55       Moreover, the Department’s interpretation does not render any part of Rule 307
       superfluous. Subsection (a) states that only the “conservation practices for each user category”
       are required, reflecting the fact that not all the conservation practices listed in subsection (b)
       and (c) are applicable to all categories of users. For instance, five of the listed practices in
       subsection (c) are applicable only to users who have the ability to pass ordinances, such as
       Rule 307(c)(5), which requires “[t]he adoption of ordinances requiring the installation of
       closed system air conditioning in all new construction and in all remodeling.” Id.
       § 3730.307(c)(5). Thus, the phrase “conservation practices as applicable to the particular user”
       in subsection (c) is not superfluous, as the plaintiffs suggest, because only some of the 10
       practices listed in that subsection will be applicable to a given user. As such, that phrase is
       included to reflect the fact that only the applicable conservation practices are required.
¶ 56       As they did with Rule 304, the plaintiffs also argue that the Department’s interpretation of
       Rule 307 contravenes the Act, citing once more to section 5’s mandate that “[t]he Department
       shall require that all feasible means reasonably available *** shall be employed to conserve
       and manage the water resources of the region and the use of water therein in accordance with
       the best modern scientific knowledge and engineering practice.” 615 ILCS 50/5 (West 2014).
       According to the plaintiffs, the phrases “all feasible means reasonably available” and “in
       accordance with the best scientific knowledge and engineering practice” require that the
       Department review all available conservation measures and tailor the required conservation
       measures to each specific user’s needs. The Department responds that section 5 does not
       provide the substantive standards to determine when conservation practices are “feasible” or
       “reasonably available,” nor does it provide guidance on what procedures should be used to
       require such practices, and as such, the Act grants the Department discretion to formulate the
       rules and procedures to implement these mandates. The Department further responds that
       requiring each permittee to comply with the specific conservation practices applicable under
       Rule 307 fulfills its obligations under section 5 of the Act. We agree with the Department.
¶ 57       Section 5 does not instruct the Department on how to determine when conservation
       practices are “feasible” or “reasonably available.” Instead, the General Assembly left that task
       to the Department, which promulgated Rule 307 in response to section 5’s mandate. Church v.
       State, 164 Ill. 2d 153, 161-62 (1995) (“Where the legislature expressly or implicitly delegates
       to an agency the authority to clarify and define a specific statutory provision, administrative
       interpretations of such statutory provisions should be given substantial weight unless they are
       arbitrary, capricious, or manifestly contrary to the statute.”). As mentioned, Rule 307 requires
       that each permit application contain a condition requiring the permittee to implement specific
       conservation practices applicable to its user category. As the Department noted, this approach
       to water conservation has resulted in a considerable reduction in the amount of diverted water

                                                   - 14 -
       the District uses for maintaining water quality in the CAWS. Moreover, we note that the
       Department’s determination that Rule 307 satisfied its obligations under section 5 of the Act
       is long held, having been first articulated in 1980 when the Rules were first promulgated. See
       Illinois Bell Telephone Co. v. Illinois Commerce Comm’n, 362 Ill. App. 3d 652, 657 (2005)
       (“The longer an agency has adhered to an interpretation of the statute, the more weight the
       interpretation deserves ***.”). Consequently, we conclude that the Department’s reasonable
       interpretation of Rule 307 does not contravene the Act.
¶ 58        The plaintiffs also cite to Prairie Rivers Network v. Illinois Pollution Control Board, 2016
       IL App (1st) 150971, in support of their argument that the Department’s interpretation of Rule
       307 is legally insufficient. In Prairie Rivers, we held that a National Pollution Discharge
       Elimination System permit did not comply with the Illinois Environmental Protection Act (415
       ILCS 5/1 et seq. (West 2014)), where the permit included a special condition “mandating that
       [the permittee’s] effluent cannot cause or contribute to water quality violations.” Prairie
       Rivers, 2016 IL App (1st) 150971, ¶ 39. We noted that the Environmental Protection Act
       specifically required that such permits contain “sufficiently stringent” terms, conditions, and
       schedules of compliance to “ ‘ensure’ ” that the permittee’s effluent discharges comply with
       numeric federal and state water quality regulations. Id. ¶ 26. Given these requirements, we
       concluded that “the special condition did not ensure compliance with water quality standards
       as it gave no guidance as to what was expected from the [permittee], nor did it allow the IEPA
       to determine whether the [permittee] was violating water quality standards.” Id. ¶ 41. Here,
       unlike in Prairie Rivers, the Act does not require permits to include “sufficiently stringent”
       terms, nor does the Act mandate that the Department “ensure” that permittees comply with
       specific conservation practices. Rather, the Act charges the Department with developing a
       water conservation program to apportion Lake Michigan water and directs it to require that
       water users employ “all reasonably available means” to conserve water resources. The
       Department, through Rule 307, has identified conservation practices that each specific user
       must undertake as a condition of receiving a water allocation permit and the District’s permit
       requires it to comply with Rule 307. As such, the permit gives the District guidance as to what
       is expected from it and it allows the Department to determine whether the District has violated
       the terms of its permit. As such, we find Prairie Rivers to be distinguishable from the instant
       case.
¶ 59        The plaintiffs’ final contention regarding Rule 307 is that the Department’s interpretation
       of Rule 307 contravenes the mandates of the Compact. We conclude, as we did for Rule 304,
       that the plaintiffs’ argument is unavailing. As mentioned, the Compact commits Illinois to
       promoting “measures, methods, technologies or practices for *** reducing a Withdrawal,
       Consumptive Use, or Diversion.” 45 ILCS 147/5 (West 2014) (“Section 1.2. Definitions.”).
       Illinois accomplishes this through Rule 307, which conditions each permit on the users’
       implementation of the conservation practices contained therein. See 17 Ill. Adm. Code
       3730.307(c) (2014). Therefore, the Department’s interpretation does not contravene the plain
       language of the Compact.
¶ 60        Having determined that the Department did not err by interpreting that its Rules do not
       allow for consideration of specific conservation practices during a permit modification
       proceeding, we also conclude that the Department did not abuse its discretion when it denied
       the plaintiffs’ efforts to introduce evidence and request discovery relating to specific
       conservation practices. See Trettenero, 333 Ill. App. 3d at 801; see also Three Angels

                                                  - 15 -
       Broadcasting Network, Inc. v. Department of Revenue, 381 Ill. App. 3d 679, 700-01 (2008)
       (finding that agency did not abuse its discretion by excluding testimony irrelevant to ultimate
       disputed issue).
¶ 61       The plaintiffs next argue that the Department erred when it used partial compliance with
       the PCB’s DO standard to determine the District’s modified discretionary diversion allocation.
¶ 62       The plaintiffs first contend that the Department erred in using the DO standard because the
       Act mandates that the Department apportion water “to maintain [the CAWS] in a reasonably
       satisfactory sanitary condition.” 615 ILCS 50/3 (West 2014). According to the plaintiffs, the
       DO standard fails to satisfy this mandate because DO is not a relevant proxy for a “sanitary
       condition” as it does not relate to “public health or to waste disposal.” The Department
       responds that the Act does not define the phrase “reasonably satisfactory sanitary condition”
       and, therefore, left it to the Department to interpret that phrase. The Department also responds
       that all of the evidence presented during the hearing disputes the plaintiffs’ contention that DO
       is not a relevant proxy for a “sanitary condition.”
¶ 63       The Department is correct that the Act does not define what it means to maintain the CAWS
       in a “reasonably satisfactory condition” and so left that determination to the Department. As
       such, we give substantial weight and deference to the Department’s reasonable interpretation.
       Church, 164 Ill. 2d at 161-62; People v. Marshall, 242 Ill. 2d 285, 297 (2011) (finding that
       silence “in the statutory language creates an ambiguity” that requires giving “substantial
       weight and deference” to the interpretation of the “agency charged with the administration and
       enforcement of the statute”). Moreover, according to the record, the Department has been using
       the DO standard for determining the allocation of water to maintain the CAWS in a “reasonably
       satisfactory sanitary condition” for over 50 years. The Department stated in its initial water
       allocation order that “DO is affected by or affects most of the parameters used to measure
       pollution and therefore *** an analysis of [DO] levels [is] an adequate indicator of water
       quality.” Moreover, the Department stated that “[t]he purpose of the discretionary flows ***
       is to add oxygen to the waterways to maintain sanitary (aerobic) conditions and to disperse
       local pollution loadings.” Given that this is the Department’s longstanding interpretation, it is
       entitled to “substantial deference.” Illinois Bell, 362 Ill. App. 3d at 657 (“The longer an agency
       has adhered to an interpretation of the statute, the more weight the interpretation deserves
       ***.”). We also note that, in the 50 years of applying this regulatory system, the General
       Assembly has never amended section 5 to suggest that the Department’s water conservation
       program was deficient, which suggests that the agency has correctly interpreted the Act’s
       mandate. See People ex rel. Birkett v. City of Chicago, 202 Ill. 2d 36, 53-54 (2002) (deferring
       to agency’s reasonable interpretation of statute in its regulations where legislature never
       intervened). Consequently, we conclude that the Department did not err when it used the DO
       regulatory standard to determine the amount of water the District required to maintain the
       CAWS in “reasonably satisfactory sanitary condition” under section 5 of the Act.
¶ 64       The plaintiffs also argue that the Rules twice reference water quality “standards,” which
       they contend supports their argument that the Department was required to consider more than
       one standard to determine the District’s allocation amount. The Department responds that
       nothing in the Rules’ plain language requires that it consider all of the water quality standards
       when determining an allocation of water. The Department further responds that it did not
       “refuse” to consider other water quality standards; rather, the plaintiffs failed to either present
       evidence of an alternative water quality standard for the Department to consider or to challenge

                                                   - 16 -
       the qualifications of those who testified in support of using the PCB DO standard. We agree
       with the Department.
¶ 65        Rule 303 defines the various categories of water users, with subsection (a)(4) defining one
       category as “[a]pplicants whose water demands are for the minimum discretionary dilution
       flows necessary to meet water quality standards in the [CAWS].” 17 Ill. Adm. Code
       3730.303(a)(4) (2014). This reference to “water quality standards” does not impose any
       obligation on the Department. Rather, Rule 303 references water quality “standards” because
       it is undisputed that the CAWS is subject to multiple regulatory standards related to water
       quality. However, the plaintiffs point to nothing in the Rules requiring that the Department
       consider all regulatory standards applicable to the CAWS when determining the District’s
       allocation of water. Consequently, the Department did not err when using the DO regulatory
       standard to determine the District’s allocation of water.
¶ 66        That said, we note that nothing in the Department’s order suggests that it did, in fact, refuse
       to consider other water quality standards when it determined the District’s water allocation.
       Instead, the record establishes that all of the relevant testimony during the administrative
       proceeding was in favor of using the DO regulatory standard and the 95% compliance rate
       because that was the best indicator of water quality in the CAWS. Dr. Melching testified on
       behalf of the District that “DO remains the primary indicator of water quality attainment (the
       sanitary condition) in the CAWS and is the most important beneficiary of discretionary
       diversion.” Twait and Injerd testified in support of both using the DO standard and the 95%
       compliance rate. The plaintiffs chose not to present evidence to contradict the considerable
       testimony in support of using the DO standard during the administrative hearing, nor did they
       offer an alternative standard for determining the discretionary diversion amount. We, therefore,
       conclude that the Department did not err in interpreting its Rules when it modified the District’s
       permit to increase its diverted water amount to a level that would ensure partial compliance
       with the PCB DO standard.
¶ 67        In sum, we conclude that the Department did not err when it determined the District’s
       modified allocation amount based on a 95% compliance rate with the PCB’s DO standard, as
       this has been the Department’s longstanding and reasonable interpretation of its obligations
       under the Act and the Rules and the only relevant testimony presented during the
       administrative hearing was in support of both the standard and the compliance rate.
¶ 68        For these reasons, we affirm the judgment of the circuit court of Cook County.

¶ 69      Affirmed.

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