Any city may, pursuant to this chapter, incur indebtedness and liability, although in excess of the income and revenue provided by it for the current fiscal year, but not so that the aggregate funded indebtedness of the city exceeds 6 per cent of the assessed value of all the real and personal property in the city, for any or all, or any part of, the following purposes:
(a) To protect the city from overflow by water.
(b) To drain the city.
(c) To secure an outlet for overflow water and drainage.