DWYER, C.J.

¶ 1 The Growth Management Hearings Boards1 are creatures of statute without inherent or common-law powers. As such, they may exercise only those powers conferred by statute, either expressly or by necessary implication. The Growth Management Act (GMA), chapter 36.70A RCW, empowers the Boards with the authority to invalidate a jurisdiction's comprehensive plan or development regulations under particular circumstances. The appellants herein contend that a Board is required to invalidate an ordinance whenever that Board finds that the challenged ordinance was adopted in violation of the State Environmental Policy Act (SEPA), chapter 43.21C RCW. We disagree. Because the Boards' power to fashion a remedy is strictly constrained by the GMA and the GMA does not provide that the Boards are required, as a matter of law, to invalidate such ordinances, the appellants' contention fails. Accordingly, we affirm the decision of the Central Puget Sound Growth Management Hearings Board.

I

¶ 2 Touchstone Corporation and Touchstone KPP Development, LLC (collectively Touchstone) own an 11.5 acre site in downtown Kirkland known as Kirkland Parkplace. In April 2007, Touchstone and two other landowners applied to the city of Kirkland (City) to amend the City's comprehensive plan and zoning code to allow taller building heights, among other changes. The City then sponsored a proposal to adopt an ordinance establishing the area containing the three properties as a planned action area.

¶ 3 The City conducted a review of the environmental impacts of the proposed amendments and enactments. In April 2008, the City issued a draft environmental impact statement (EIS) that evaluated only the proposed action and a "no action" scenario; it did not evaluate any alternative actions. In October 2008, the City issued the final EIS. The final EIS contained one additional alternative, which was merely a slightly modified version of the proposed action.

¶ 4 The City then enacted several ordinances implementing the landowners' and the City's proposals. The City amended its comprehensive plan through Ordinance No. 4170. The City amended its zoning code through Ordinance No. 4171. The City also enacted Ordinance No. 4173 and Ordinance No. 4174 in order to amend other portions of the comprehensive plan and the zoning code. In addition, the City enacted Ordinance No. 4172, which adopted design review guidelines, and Ordinance No. 4175, which created a planned action area.

¶ 5 Davidson Serles & Associates and TR Continental Plaza Corp. (collectively Davidson), property owners with land neighboring Touchstone's Parkplace property to the southeast, each filed petitions for review with the Central Puget Sound Growth Management Hearings Board, challenging the enactment of the comprehensive plan and zoning code amendments contained within Ordinances No. 4170 and No. 4171. They did not challenge the validity of the other four ordinances before the Board. Their appeals were consolidated. Touchstone was allowed to intervene in the action to defend the validity of the City's ordinances.

¶ 6 Among other rulings, the Board determined that the final EIS was inadequate for failure to consider alternatives. The Board found that, as a result, the City was not in compliance with SEPA and remanded for the City to come into compliance. However, the Board determined that none of the goals of the GMA would be undermined were the ordinances to remain in effect. As a result of this determination, the Board did not invalidate the ordinances.

¶ 7 Davidson appealed the Board's decision to the superior court. Davidson then timely sought direct appellate review pursuant to the Administrative Procedure Act2 (APA), RCW 34.05.518(3) and (6), by filing an application requesting that the Board issue a certificate of appealability.3 The Board determined that delay in Davidson's appeal would be detrimental to Davidson and that direct review by the Court of Appeals would likely have significant precedential value. Thus, the Board issued a certificate of appealability. Davidson then timely filed a motion for discretionary review with this court. A commissioner of our court granted discretionary review.

II

¶ 8 We review a decision of the Board pursuant to the APA.4 Thurston Cnty. v. Cooper Point Ass'n, 148 Wn.2d 1, 7, 57 P.3d 1156 (2002). The APA requires that we base our review upon the record made before the Board. City of Redmond v. Cent. Puget Sound Growth Mgmt. Hearings Bd., 136 Wn.2d 38, 45, 959 P.2d 1091 (1998). We review the Board's legal conclusions de novo, giving substantial weight to the Board's interpretation of the statute it administers. City of Redmond, 136 Wash.2d at 46, 959 P.2d 1091; King Cnty. v. Cent. Puget Sound Growth Mgmt. Hearings Bd., 142 Wn.2d 543, 555, 14 P.3d 133 (2000). The burden of demonstrating the invalidity of the Board's action is on the party asserting invalidity. RCW 34.05.570(1)(a). Thus, Davidson has the burden of demonstrating the invalidity of the Board's decision not to invalidate the City's ordinances. RCW 34.05.570(3) sets forth nine bases for granting relief from the Board's decision, including the only one asserted by Davidson: that "[t]he agency has erroneously interpreted or applied the law."5

III

¶ 9 Davidson contends that the Board was required, as a matter of law, to invalidate the two challenged ordinances—Ordinances No. 4170 and No. 4171—because the EIS supporting those ordinances was found to be inadequate. We disagree.

¶ 10 An analysis of the Board's authority "to impose or fashion a remedy in any given case begins with the principle that administrative agencies are creatures of the Legislature, without inherent or common-law powers and, as such, may exercise only those powers conferred by statute, either expressly or by necessary implication." Skagit Surveyors & Eng'rs, LLC v. Friends of Skagit Cnty., 135 Wn.2d 542, 558, 958 P.2d 962 (1998) (citing Kaiser Aluminum & Chem. Corp. v. Dep't of Labor & Indus., 121 Wn.2d 776, 780, 854 P.2d 611 (1993); Human Rights Comm'n v. Cheney Sch. Dist. 30, 97 Wn.2d 118, 125, 641 P.2d 163 (1982)). "The power of an administrative tribunal to fashion a remedy is strictly limited by statute." Skagit Surveyors, 135 Wash.2d at 558, 958 P.2d 962. Accordingly, we must look to the GMA itself to determine the authority of the Board.

¶ 11 The Board has jurisdiction to hear and determine SEPA claims related to the adoption or amendment of a comprehensive plan or development regulation.

RCW 36.70A.280(1) (emphasis added). RCW 36.70A.300(1) indicates that the Board shall issue a final order "based exclusively on whether or not [a jurisdiction] is in compliance with the requirements of this chapter. . . or chapter 43.21C RCW." In its final order, the Board may find compliance "with the requirements of [the GMA] . . . or chapter 43.21C RCW" or may find that the jurisdiction is not in compliance "with the requirements of [the GMA] . . . or chapter 43.21C RCW" and remand the matter to the jurisdiction. RCW 36.70A.300(3). Thus, the legislature has empowered the Board to find noncompliance with SEPA and remand to allow the jurisdiction to come into compliance.

¶ 12 Even upon a Board's finding of noncompliance and order of remand, comprehensive plans and development regulations remain valid "[u]nless a board makes a determination of invalidity as provided in RCW 36.70A.302." RCW 36.70A.300(4).6 A Board's authority to make a determination of invalidity is limited by the statute, which provides:

RCW 36.70A.302(1).7 In sum, the Board is empowered with the authority to invalidate a jurisdiction's comprehensive plan or development regulations where the Board (1) makes a finding of noncompliance; (2) remands; (3) makes a determination supported by findings and conclusions that the continued validity of the plan or regulation will substantially interfere with the fulfillment of the goals of the GMA; and (4) specifies the portion of the action that is invalid and explains why. RCW 36.70A.302(1).

¶ 13 However, contrary to Davidson's assertions, the legislature did not grant the Board the authority to invalidate comprehensive plans or development regulations simply because those enactments were based on an inadequate EIS. Rather, the Board is restricted by the plain terms of the GMA.

¶ 14 To find invalidity in this instance, the Board would have needed to determine that the continued validity of the SEPA-noncompliant ordinances would "substantially interfere with the fulfillment of the goals" of the GMA.8 RCW 36.70A.302(1)(b). One of the GMA goals that was considered by the Board herein was Goal 10, which states: "Protect the environment and enhance the state's high quality of life, including air and water quality, and the availability of water." RCW 36.70A.020(10). On the appropriate facts, the Board could find that failure to properly conduct the required environmental review for a city or county action interfered with fulfillment of the GMA's environmental goal, and, upon such a finding, could invalidate the relevant ordinance. This case does not, however, present such appropriate facts. As the Board herein stated:

Davidson Serles v. City of Kirkland, No. 09-3-0007c (Cent. Puget Sound Growth Mgmt. Hr'gs Bd. Final Decision and Order Oct. 5, 2009).

¶ 15 Notwithstanding the Board's limited statutory authority, Davidson contends that the Board was required to render the ordinances invalid in order to fulfill its duties under SEPA. Quasi-judicial bodies such as the Growth Management Hearings Boards are categorically exempt from SEPA's threshold determination and EIS requirements. WAC 197-11-800(11). Davidson contends, however, that the Boards are still bound by SEPA's other requirements— namely, SEPA's pronouncements that state agencies shall interpret and administer the laws of the State of Washington in accordance with SEPA's policies, RCW 43.21C.030(1), and shall

RCW 43.21C.020(2).

¶ 16 SEPA overlays and supplements all other state laws. Donwood, Inc. v. Spokane Cnty., 90 Wn.App. 389, 398, 957 P.2d 775 (1998); see also Dep't of Natural Res. v. Thurston Cnty., 92 Wn.2d 656, 664, 601 P.2d 494 (1979) ("SEPA is an overlay of law which supplements existing statutory authority."). Thus, the Boards are constrained by SEPA's policies. However, the Board's decision herein to remand to the City to comply with SEPA is consistent with the policies of SEPA. The Boards are not required, as a matter of law, to always invalidate an ordinance that was enacted based on a noncompliant EIS in order for the Boards to abide by SEPA's policies. In fact, such a rule conflicts with the Boards' statutory authority to invalidate actions, which is not mandatory and certainly is not absolute. Therefore, the Board herein did not violate SEPA by determining that invalidation of the ordinances was not appropriate and by remanding to the City.9

¶ 17 Davidson also contends that the Board was required to invalidate the ordinances upon its findings of noncompliance with SEPA because several judicial decisions set aside actions that were made in violation of SEPA's requirements. Appellant's Br. at 25-27 (citing Weyerhaeuser v. Pierce Cnty., 124 Wn.2d 26, 47, 873 P.2d 498 (1994); Noel v. Cole, 98 Wn.2d 375, 655 P.2d 245 (1982); Barrie v. Kitsap Cnty., 93 Wn.2d 843, 861, 613 P.2d 1148 (1980); Lassila v. City of Wenatchee, 89 Wn.2d 804, 816-17, 576 P.2d 54 (1978); Eastlake Cmty. Council v. Roanoke Assocs., Inc., 82 Wn.2d 475, 487, 513 P.2d 36 (1973)). As discussed above, the Boards are creatures of the legislature, without inherent or common-law powers. Skagit Surveyors, 135 Wash.2d at 558, 958 P.2d 962. As such, the Boards may exercise only those powers conferred upon them by statute, and their power to fashion a remedy is strictly limited by the GMA. Skagit Surveyors, 135 Wash.2d at 558, 958 P.2d 962. The remedy that the judiciary has fashioned when presented with a violation of SEPA's requirement cannot alter the Boards' statutory authority. The Boards take their power from and are constrained by applicable statutes as enacted by the legislature.

¶ 18 Affirmed.10

We concur: APPELWICK and GROSSE, JJ.