Watershed conservation districts may be established as provided in this chapter within one or more soil and water conservation districts to develop and execute plans and programs relating to a phase of the control or prevention of soil erosion or flooding; the conservation, protection, improvement, development, or utilization of soil and water resources; stormwater management; or the disposal of water. This authority applies, but is not limited to, the planning and carrying out of works of improvement for the foregoing purposes which may be considered by the United States Secretary of Agriculture under the Watershed and Flood Prevention Act, 68 Stat. 666, as amended, and does not affect the existing procedures followed by local interests in the planning and construction of water resources development projects of other agencies. However, this chapter may be used when, in the opinion of those agencies, the use is advisable or expedient.