This chapter provides an alternative method for the formation of improvement districts for the purpose of cooperating and contracting with the United States and agencies thereof pursuant to the Irrigation District Federal Cooperation Law as contained in Chapter 2 (commencing with Section 23175) of Part 6 of Division 11, or for the purpose of sewage disposal, irrigation water service by a system of pumps, conduits, or both, maintenance of irrigation works, drainage, or distribution of water. The term “district” or “districts” as used in the Irrigation District Federal Cooperation Law shall include improvement districts formed pursuant to the provisions of this chapter. This chapter shall not apply to or affect any other provisions of this division for the formation of improvement districts or the incurring of indebtedness therefor.