The Governor may designate, from time to time, and may revoke previous designations of, the area within a 20-mile airline radius of the site of principal construction of any water construction project undertaken by the State as an impact area when:
(a)
He is requested to do so by the county board of supervisors or the city council of any county or city within the impact area; and
(b)
He finds that:
(1)
Such construction will cause a sudden influx of people into the impact area.
(2)
The construction will require more than 12 months to complete.
(3)
The construction will result in serious fiscal problems to the affected local governments.
(4)
Peak construction employment on the project within the impact area is estimated by the Department of Water Resources to total more than 500 employees.
(5)
The increase in population in the impact area, found by multiplying such peak construction employment as estimated by the Department of Water Resources by 4.5, equals at least 20 percent of the estimated population in the area on July 1st of the year prior to the date that construction was started. At any time that the increase in population falls below 20 percent of the estimated population of the area, the designation shall terminate as of the following June 30th. All population data are to be determined by the Department of Finance.