The board has no power, authority, or jurisdiction, either directly or indirectly, except as provided in this division, to incur any indebtedness or expend any money or adopt or carry into effect any plan or project or to acquire any lands, rights of way, or easements, or to do any work, or cause any work to be performed, for which any land lying within the drainage district is to be assessed, except to maintain, repair, and operate its existing works of reclamation and flood control and to complete, maintain and operate any project adopted by the board prior to April 1, 1923, with the existing powers to levy assessments therefor.