The directors of the soil and water conservation district or districts in which the watershed improvement district is situated shall be the governing body of the watershed improvement district. They may appoint, in consultation with and subject to the approval of the Virginia Soil and Water Conservation Board, three trustees who shall be owners of land within the watershed improvement district. The trustees shall exercise the administrative duties and powers delegated to them by the directors of the soil and water conservation district or districts. The trustees shall hold office at the will of the directors of the soil and water conservation district or districts and the Virginia Soil and Water Conservation Board. The trustees shall designate a chairman and may change such designation. One of the trustees may be selected as treasurer and shall be responsible for the safekeeping of the funds of the watershed improvement district. When a watershed improvement district lies in more than one soil and water conservation district, the directors of all such districts shall act jointly as the governing body of the watershed improvement district.