For purposes of cooperating with landowners or any other agency or for purposes of cooperating with the United States under provisions of the Watershed Protection and Flood Prevention Act (Chapter 656, Public Law 566, 83rd Cong., 2nd Session), and all acts amendatory thereof or supplementary thereto, lands which need not be contiguous may be formed into an improvement district for constructing, both in or for the improvement district, one or more of the following:
(a) Flood prevention improvements, including structural and land treatment measures.
(b) Improvements for the agricultural phases of conservation, development, utilization, drainage disposal, and distribution of water.
(c) Improvements for prevention or stabilization of soil erosion.
(Repealed and added by Stats. 1975, Ch. 513.)