Actual construction work shall be commenced on any project for which permit has been granted within such reasonable time as shall be prescribed by the department, and shall thereafter be prosecuted with diligence and completed within the time prescribed by the department. The department, in fixing the time for the commencement of the work, or for the completion thereof and the application of the water to the beneficial use prescribed in the permit, shall take into consideration the cost and magnitude of the project and the engineering and physical features to be encountered, and shall allow such time as shall be reasonable and just under the conditions then existing, having due regard for the public welfare and public interests affected. For good cause shown, the department shall extend the time or times fixed as aforesaid, and shall grant such further period or periods as may be reasonably necessary, having due regard to the good faith of the applicant and the public interests affected. Good cause includes prevention or restriction of water use by operation of federal laws for the time or times fixed for commencing work, completing work, and applying water to beneficial use otherwise authorized under a water right permit issued for a federal reclamation project. In fixing construction schedules and the time, or extension of time, for application of water to beneficial use for municipal water supply purposes, the department shall also take into consideration the term and amount of financing required to complete the project, delays that may result from planned and existing conservation and water use efficiency measures implemented by the public water system, and the supply needs of the public water system's service area, consistent with an approved comprehensive plan under chapter 36.70A
RCW, or in the absence of such a plan, a county-approved comprehensive plan under chapter 36.70
RCW or a plan approved under chapter 35.63
RCW, and related water demand projections prepared by public water systems in accordance with state law. An existing comprehensive plan under chapter 36.70A
RCW, plan under chapter 35.63
RCW, or demand projection may be used. If the terms of the permit or extension thereof, are not complied with the department shall give notice by registered mail that such permit will be canceled unless the holders thereof shall show cause within sixty days why the same should not be so canceled. If cause is not shown, the permit shall be canceled.