When the local undertakings provided for in NRS 539.363 to 539.395, inclusive, are accomplished and paid for, a showing to that effect shall be made to the board of directors of the district, and upon the approval thereof by such board the terms of office of the local directors shall terminate, and any moneys of such division in the district treasury shall be appropriately credited to the lands of the division in connection with future assessments against such lands.
NRS 539.400