Sec. 27. In developing a plan to improve water quality or mitigate flooding in the part of the basin described in a cooperative agreement entered into under section 26 of this chapter, the commission shall determine the best method and manner of improving water quality or mitigating flooding, giving consideration to the following:
(1) The increase infiltration method.
(2) The channel improvement method.
(3) The wetland restoration method.
(4) Flood plain regulation.
(5) All nonstructural methods.