When more than one petition is filed covering portions of the same territory, the board of land and natural resources may consolidate the petitions. Having received the petitions, on the basis of such evidence as may be submitted to it by the petitioners and on the findings of investigations or surveys made by or for it, or by other governmental agencies, the board shall establish such projects as it deems necessary to carry out the purposes of this chapter. Before making a final determination to establish a project or projects, the board shall hold a hearing, notice of which shall be duly advertised in the same manner and form, as nearly as may be, as provided in section 174-17. The department shall assure that adequate water is reserved for future development and use on Hawaiian home lands that could be served by the proposed water project.