I respectfully dissent.
I disagree with the posture in which the majority have placed the matter on appeal, which is the predicate for their lengthy discussion on the question of reemployment rights under Education Code sections 87744 and *93087745; it is my opinion that the substance of this case is dealt with by Education Code section 87743 which relates to layoff, not reemployment.
Additionally, the majority opinion gives no more than lip service to the trial court’s determination that plaintiffs’ action was barred by laches. In their conclusion on that question, I believe they are wrong. I view that question as pivotal to the proper disposition of the matter.
In order to adequately state my dissenting decision, I set forth the following factual and legal analysis to support my belief that the judgment should be affirmed.
In 1977, the Educational Employment Relations Board (now the Public Employment Relations Board [see Gov. Code, § 3541]) directed that the Shasta-Tehama-Trinity Joint Community College District (District) part-time (temporary) certificated instructors be included in the same bargaining unit with the District’s full-time (permanent) certificated instructors.
In 1978, the Shasta College Faculty Association (Association), the exclusive bargaining agent for the unit, negotiated a master contract agreement with the District on behalf of all certificated instructors. A high priority item in those negotiations was job security for part-time instructors. Consequently, eligible part-time instructors were accorded layoff and reemployment rights in part-time (evening) courses on the basis of seniority in the part-time service.1 Those contract provisions resulted in the District’s *931establishing, at the Association’s insistence, a separate part-time seniority list to govern assignments into the evening classes.
In 1982, in the face of financial constraints, the District elected to discontinue or reduce services in several areas of its curriculum, necessitating the layoff of a number of full-time, certificated faculty members, including plaintiffs, for the 1982-1983 school year. On April 21, 1982, pursuant to Education Code sections 87740 and 87743, the affected employees were provided a layoff hearing before an administrative law judge.2 Each of the plaintiffs was represented by counsel at the hearing. At the hearing plaintiffs did not challenge the use of dual seniority lists for full-time and part-time instructors, nor did they assert any right to displace, or “bump,” any part-time instructors teaching in areas for which plaintiffs were credentialed and qualified. The administrative law judge found cause for not reemploying plaintiffs because of discontinuance or reduction of certain services, and he further found that “[n]o certificated employees with less seniority are being retained for service which any [laid-off employee] is certificated and competent to render.”
On May 5, 1982, the District’s governing board adopted the administrative law judge’s decision. That same month, the fall 1982 teaching schedule was published and distributed. The schedule included evening classes to be taught by part-time instructors who were being reemployed for the following school year. Following receipt of that schedule, plaintiffs did not request a reconsideration of the layoff decision (see Gov. Code, § 11521), nor did they file a petition for a writ of administrative mandamus challenging the decision (see Gov. Code, § 11523; Code Civ. Proc., § 1094.5).
On June 11, 1982, by letter to the District, plaintiff Dick Kakuda asked for a position teaching any of 11 evening courses being offered in the fall 1982 semester, or any other courses for which his credential qualified him. His request was not construed by the District to be an assertion of a reemployment right, and the request was apparently denied. Kakuda made no objection at that time.
When the spring 1983 teaching schedule was published, the District again heard no protest from plaintiffs or from the Association.
*932In mid-April 1983, one year after the layoff hearing, the Association filed grievances on plaintiffs’ behalf. The Association challenged the District’s use of dual seniority lists under the master contract, and it requested plaintiffs’ reinstatement with backpay. The District denied the grievances in September 1983, and the Association requested binding arbitration. An arbitration hearing was held January 19, 1984, and a decision adverse to the Association was rendered May 25, 1984.
The individual grievants subsequently filed the instant petition for a writ of mandate seeking reinstatement with backpay. They further petitioned the superior court to vacate the arbitrator’s decision as contrary to public policy and beyond the scope of the arbitrator’s authority.3 Plaintiffs’ position, in essence, was that the Education Code accords them, as full-time (permanent) certificated instructors, layoff and reemployment rights not accorded part-time (temporary) instructors.4 They asserted that their statutory reemployment rights preempt the part-time instructors’ contractual rights to the extent part-time instructors have been employed, beginning with the 1982-*9331983 school year, to teach evening courses for which plaintiffs are credentialed and qualified. Moreover, to the extent the master contract protects part-time instructors at the expense of full-time instructors, it is contrary to public policy and presents a nonarbitrable matter.
The District disagreed with plaintiffs on the merits of the controversy. In addition, the District interposed the defenses of laches and statute of limitations. The District maintained that plaintiffs were asserting nothing more than bumping rights, which should have been advanced at the layoff hearing in April 1982. In reliance on plaintiffs’ apparent acquiescence in the District’s use of dual seniority lists, part-time instructors were reemployed to teach in the evening division for the following school year. Despite their knowledge of the pertinent facts in April or, at the latest, May of 1982, plaintiffs first raised this issue one year later, in April 1983, when they filed their grievances under the master contract. The District argued the delay was unreasonable in the circumstances, and the District was prejudiced by it in that it had previously reemployed and paid the part-time instructors for the evening positions now claimed by plaintiffs. Moreover, under the terms of the master contract, the part-time instructors could not be dismissed without cause, and dismissal of the part-time instructors to accommodate plaintiffs’ demands would potentially cause additional litigation for the District. In addition, the District asserted plaintiffs’ exclusive remedy for any asserted violation of bumping rights was by way of administrative mandamus (Code Civ. Proc., § 1094.5), not ordinary mandamus (Code Civ. Proc., § 1085). Accordingly, plaintiffs’ action is barred by the 30-day limitation period for filing a petition for writ of administrative mandamus. (See Gov. Code, § 11523.)
Following a hearing at which the records of the prior layoff and arbitration hearings, as well as testimony of the District’s superintendent, were received into evidence, the superior court found that, regardless of the merits of plaintiffs’ claim, they unreasonably delayed asserting it, to the District’s detriment.5 The writ petition was denied, as was the petition to vacate the arbitration decision, and judgment was entered for the District accordingly.
“The defense of laches requires unreasonable delay plus either acquiescence in the act about which plaintiff complains or prejudice to the defendant resulting from the delay. ... ‘If because of his delay in seeking his *934remedy, without offering a satisfactory explanation for the delay, a prejudice results to his adversary, he will be precluded from enforcing his demand. It is not so much a question of the lapse of time as it is to determine whether prejudice has resulted. If the delay has caused no material change in statu quo, ante, i.e., no detriment suffered by the party pleading the laches, his plea is in vain.’ ” (Conti v. Board of Civil Service Commissioners (1969) 1 Cal.3d 351, 359-360 [82 Cal.Rptr. 337, 461 P.2d 617], quoting Brown v. State Personnel Board (1941) 43 Cal.App.2d 70, 79 [110 P.2d 497], fns. omitted.)
In an action by a discharged public employee for reinstatement with backpay, the defense of laches may be established by a showing that the position for which reinstatement is sought has been filled by another; the resulting double payment by the employer would constitute prejudice. (Conti, supra, 1 Cal.3d at p. 360; Vernon Fire Fighters Assn. v. City of Vernon (1986) 178 Cal.App.3d 710, 726 [223 Cal.Rptr. 871].) This type of prejudice is aggravated when the position sought by the discharged employee has since been filled by one who may not be terminated except for cause. Thus, in Kimberlin v. L. A. City High School Dist. (1953) 115 Cal.App.2d 459 [252 P.2d 344] (disapproved on another point in Conti, supra, at p. 362), a teacher sought reinstatement and backpay about one year after his discharge. In the interim, the school district had hired and paid another teacher, on a written contract basis, for the position demanded by the plaintiff. This was sufficient to sustain the school district’s laches defense: “This notwithstanding the fact that at the trial, appellant, through his counsel, offered to waive his right to receive compensation for the period prior to judgment should the court order his reinstatement. Without undertaking to determine the effectiveness of such purported waiver, the fact remains that another had been appointed to the position formerly held by appellant, whose employment may not be terminated except for cause. [Citation.] Thus the respondent district would be prejudiced if appellant were now reinstated by reason of the financial burden incident to the addition of another employee.” (115 Cal.App.2d at p.465.)
“Ordinarily laches is a question of fact. [Citation.] Whether laches has occurred in a particular case presents a question primarily for the trial court, and an appellate court will not interfere with a trial court’s discretion in this respect unless it is obvious that manifest injustice has been done or unless its conclusions do not find substantial support in the evidence. [Citation.]” (Chang v. City of Palos Verdes Estates (1979) 98 Cal.App.3d 557, 563 [159 Cal.Rptr. 630]; see Vernon Fire Fighters Assn. v. City of Vernon, supra, 178 Cal.App.3d at pp. 718-719 [substantial evidence standard of review].) I review the record accordingly.
*935Initially, in order to place this matter in what I believe is its proper perspective, I observe what this case is not about. Regardless of the label plaintiffs and my colleagues in the majority opinion attach to it, this case is not about reemployment rights under Education Code sections 87744 and 87745. Plaintiffs were laid off under Education Code section 87743 after the District decided to reduce or discontinue particular services that plaintiffs had theretofore been employed to render. For instructors so laid off, Education Code sections 87744 and 87745 provide a preferred right to reappointment if, within the specified time periods, “the discontinued service is reestablished.”6 I fail to discern any evidence in this case that that predicate to plaintiffs’ preferred right to reappointment had occurred. Indeed, I believe the evidence from the District is uncontroverted, that the discontinued services for which plaintiffs were laid off had not been reestablished. Under those circumstances, Education Code sections 87744 and 87745 do not come into play. Reduced to its essence, plaintiffs’ complaint is that assertedly less senior, part-time instructors were retained by the District to render services which plaintiffs were certificated and competent to render. This places plaintiffs’ claim within the purview of Education Code section 87743, which relates to layoff, not reemployment, rights.
The record discloses that plaintiffs, aware of the District’s use of dual seniority lists for full-time and part-time instructors, failed to assert at their layoff hearing any right to bump part-time instructors who were being retained.7 Within 30 days of the District’s adoption of the administrative decision finding cause for plaintiffs’ layoff, the District published and distributed its teaching assignments for the 1982-1983 school year. Assuming the publication of these assignments was plaintiffs’ first notice that part-time *936instructors were being retained to teach evening classes for which plaintiffs were credentialed and qualified, plaintiffs did not, despite their right to do so, request a reconsideration of the layoff decision. Nor did they petition the superior court for a writ of administrative mandamus. Plaintiffs’ first indication to the District that they considered the use of dual seniority lists improper in making teaching assignments came one year after the layoff hearing. In the interim, and in reliance on plaintiffs’ apparent concurrence in the District’s interpretation of the master contract, the District retained and paid part-time instructors to teach the classes now claimed, with back-pay, by plaintiffs. Moreover, by the terms of the master contract, the retained part-time instructors were not subject to dismissal except for cause.8 Finally, plaintiffs have simply offered no satisfactory explanation for their delay in asserting the invalidity of the dual seniority lists.9 The record amply supports the superior court’s finding that plaintiffs unreasonably delayed asserting their claim, acquiescing for one year in the District’s interpretation of the master contract, to the District’s prejudice. Perceiving no manifest injustice in the circumstances, I would conclude the court did not abuse its discretion in sustaining the District’s laches defense.
In any event, I am persuaded by the District’s argument that, because plaintiffs’ claim is essentially an assertion of bumping rights (in the guise of an assertion of reemployment rights), their exclusive remedy, assuming the assertion has merit, was through the administrative layoff procedure. Having failed to request reconsideration of the administrative decision or to seek judicial review by petition for writ of administrative mandamus within the 30-day limitation period (see Gov. Code, §§ 11521, 11523), plaintiffs are barred from asserting their claim in this proceeding. (See Temescal Water *937Co. v. Dept. Public Works (1955) 44 Cal.2d 90, 106 [280 P.2d 1]; Compton v. Board of Trustees (1975) 49 Cal.App.3d 150, 154, 159 [122 Cal.Rptr. 493].) Moreover, to the extent plaintiffs argue the evidence giving rise to their claim did not arise until after the administrative decision—i.e., the subsequent publication and distribution of the 1982-1983 teaching assignments— the fact remains that this evidence came to light within the 30-day period for administrative reconsideration of the decision. By failing to avail themselves of that opportunity for reconsideration, plaintiffs have simply waived judicial review of the matter for their lack of reasonable diligence. (Cf. Schoenen v. Board of Medical Exrs. (1966) 245 Cal.App.2d 909, 915 [54 Cal.Rptr. 364].)
The parties raise a number of other procedural points, as well as renewing their arguments made below on the merits of plaintiffs’ claim; because of my conclusion that laches was properly invoked, I have not addressed those arguments.
I would affirm the judgment.
Article I, section G, of the master contract agreement, relating to organizational security, provided: “1. Part-time Employees [fl] a. Reemployment [j[] (1) A part-time certificated employee who has taught the equivalent of three semesters out of the last six semesters can expect to be rehired. Division Directors will render to the part-time certificated employee notification setting forth reasons for termination of any class. Upon request of the employee, he/she shall be given both cause for termination and due process before the Board of Trustees in open and or closed session as requested by the employee, [ft] (2) In the event of temporary termination due to insufficient class enrollment, the said instructors will be offered the first opportunity for reemployment in classes for which they are credentialed and qualified, [j[] b. Layoffs and Termination [j[] (1) Layoffs for instructors who have taught the equivalent of three semesters out of the last six semesters and who have been laid off for lack of enrollment will be on a seniority basis in the area of certification. [H] (2) If it becomes necessary, as provided for under the provisions of Article II—Hours of Employment, for a full-time instructor to replace a part-time instructor, layoffs of the part-time instructor shall be made on the basis of the part-time seniority list; and, if possible, the part-time instructor reassigned. Part-time instructors with the least seniority in the bargaining unit shall be the first to be temporarily terminated. Seniority in the bargaining unit shall be determined on the basis of first-rendered paid service.”
Thus, the master contract accorded part-time instructors more job security and procedural rights than otherwise provided under the Education Code. (See Ed. Code, § 87742 [“Governing boards of community college districts may dismiss temporary employees at any time at *931the pleasure of the board.”]; Saraceno v. Foothill-De Anza Community College Dist. (1982) 127 Cal.App.3d 850, 856-857 [179 Cal.Rptr. 742].)
The District also gave notice (accusations) to a number of part-time instructors, but, as those instructors were not entitled to a hearing before an administrative law judge (the master contract provided for a hearing before only the board of trustees), the accusations were dismissed by the administrative law judge. The record is silent as to the further disposition of those part-time instructors.
Although the Association disagrees with the arbitrator’s decision, it chose not to challenge it. The Association asserts that its interest at this point lies in supporting the public policy favoring the finality of arbitration decisions in the field of labor relations. Accordingly, pursuant to Code of Civil Procedure section 1285, the Association is a named respondent on the petition to vacate the arbitrator’s decision.
Education Code section 87743, governing layoff of permanent employees, and as it read at the time in question, provides, in pertinent part: “Whenever in any school year the average daily attendance in all of the schools of a district for the first six months in which school is in session shall have declined below the corresponding period of either of the previous two school years, or whenever a particular kind of service is to be reduced or discontinued not later than the beginning of the following school year, and when in the opinion of the governing board of said district it shall have become necessary by reason of either of such conditions to decrease the number of regular employees in said district, the said governing board may terminate the services of not more than a corresponding percentage of the certificated employees of said district, regular as well as contract, at the close of the school year; provided, that the services of no regular employee may be terminated under the provisions of this section while any contract employee, or any other employee with less seniority, is retained to render a service which said regular employee is certificated and competent to render. . . . [H] The board shall make assignments and reassignments in such a manner that employees shall be retained to render any service which their seniority and qualifications entitle them to render.”
Education Code section 87744, governing reemployment rights for regular (tenured) instructors, provides, in pertinent part: “Any regular employee whose services have been terminated as provided in Section 87743 shall have the following rights: [][] (a) For the period of 39 months from the date of such termination, any employee who in the meantime has not attained the age of 70 years shall have the preferred right to reappointment, in the order of original employment as determined by the board in accordance with the provisions of Sections 87401 to 87424, inclusive, if the number of employees is increased or the discontinued service is reestablished, with no requirements that were not imposed upon other employees who continued in service. However, no contract or other employee with less seniority shall be employed to render a service which the employee is certificated and competent to render.”
Education Code section 87745 provides similar reemployment rights for contract (probationary) instructors for a period of 24 months and subject to the rights of tenured instructors.
Although not raised by the District as a defense, the court also concluded, by parity of reasoning, that plaintiffs’ claim was further barred by the doctrine of equitable estoppel. As I conclude the court properly held for the District on its laches defense, I need not address the propriety of the court’s alternative holding on a defense not specifically pleaded.
Education Code section 87743 also provides for layoff when, because of decline in average daily attendance, it becomes necessary to reduce the number of instructors. Education Code sections 87744 and 87745 provide a corresponding preferred right to reappointment if the number of regular or contract (i.e., “full-time”) instructors is subsequently increased. Because plaintiffs were not laid off because of decline in average daily attendance, a subsequent increase in the number of the District’s instructors would not alone trigger their preferred right of reappointment. In any event, the uncontroverted evidence is that the District’s average daily attendance and its number of instructors had consistently decreased since the 1982 layoff.
As the superior court found, “The Accusations for termination of both regular [full-time] and temporary [part-time] employees referred prospectively to the 1982-83 academic year. Only a small portion of the persons contained on each of the two separate seniority lists received Accusations. Regardless of the statutory propriety of the accusations to the temporary employees, said process at the very least put the Association and its members on notice that the District planned to rehire for the academic year 1982-83 those temporary employees in the night school who had not received Accusations. Despite this patent indication of the District’s interpretation of Section G [of the Master Contract], neither the Association nor its members even mentioned, much less asserted, any bumping rights under Education Code Section 87743 against the temporary nighttime instructors at the layoff hearings.”
Plaintiffs assert that consideration of this fact as an element of prejudice in support of the District’s laches defense improperly reaches the merits of the controversy. I disagree. Education Code section 87742 provides: “Governing boards of community college districts may dismiss temporary employees at any time at the pleasure of the board.” (Italics added.) When the Education Code does not provide a mandatory, inflexible standard in conflict with a contract proposal, that proposal is negotiable, and employees may contract for rights greater than those provided by statute. (San Mateo City School Dist. v. Public Employment Relations Bd. (1983) 33 Cal.3d 850, 866 [191 Cal.Rptr. 800, 663 P.2d 523].) And I perceive no inherent conflict between the part-time instructors’ contractual right to dismissal only for cause and the full-time instructors’ statutory layoff and reemployment rights.
Plaintiffs rely on Education Code section 87744, subdivision (b), which provides: “The aforesaid right to reappointment may be waived by the employee, without prejudice, for not more than one school year, unless the board extends this right, but such waiver shall not deprive the employee of his or her right to subsequent offers of reappointment.” Plaintiffs argue that, between April 1982 and April 1983, they so waived their right to reappointment and, consequently, cannot now be penalized for having failed to assert it earlier. I am not persuaded. In my view, Education Code section 87744, subdivision (b), contemplates first an offer of reappointment. No such offers were made in this case, and thus the threshold for waiver without prejudice was never reached.