A. When a contract is entered into between the United States and an irrigation district pursuant to this article, the engineering investigations, letting of contracts by the district and related undertakings related to the construction of works, purchase thereof or of a water supply, or acquisition of property, may be done and performed by the United States or the district, or as provided by the contract between the United States and district.

B. The officers, agents and employes of the United States or the district may enter upon any land in the district to make surveys or locate sites for construction of works in furtherance of such engineering investigations.