I
The Salt River Project (SRP) is a large Arizona irrigation project, designed and constructed by the Bureau of Reclamation (Bureau), an agency of the Department of the Interior.
The Salt River Valley Water Users Association (Association) was created in 1903 as a state corporation for the purpose of dealing with the United States respecting the creation of SRP. In 1904, pursuant to an agreement between the United States and the Association, the United States agreed to construct the project and the Association agreed to repay the costs of construction. The Bureau was given the responsibility for designing and constructing the project and proceeded to do so. The Power Canal Diversion Dam was a component of the project. In a contract dated September 6, 1917, the federal government transferred the care, operation and maintenance of the project to the Association. The contract further provided that the Association would hold the United States harmless from any damages to property arising out of the care, operation and maintenance of the project. The contract allowed the United States certain inspection rights and provided for termination upon notice by either the United States or the Association.
On November 26, 1935, another contract was signed by the Secretary of the Interior and the Association for repairing and improving the project. This contract also provided that the Association assume the care, operation and maintenance of the improvements and that the Association hold the United States harmless for any injury or damages to persons or property arising out of the care, operation and maintenance of the project. The right to inspect was again reserved by the United States.
The Salt River Project Agricultural Improvement and Power District (District) was formed in 1937. In an agreement reached with the Association, the Association made the District its contracting agent and transferred to the District all its property. The Association in turn agreed to continue to maintain and operate the SRP.
By the 1950’s, use of the diversion dam had been completely discontinued. No formal action was taken, however, by the Association or the District to return possession, control or operation and maintenance of the dam to the federal government or to terminate the 1917 or 1935 contracts.
The land under and surrounding the diversion dam is owned by the United States. The surrounding land is managed by the Tonto National Forest, a component of the United States Forest Service. The Forest Service is an agency of the Department of Agriculture.
On April 13, 1979, Jose Borquez and Jonathan Dahlin were drowned and Zane Dah-lin was injured at the diversion dam when they attempted to walk across the top of the dam. Zane Dahlin and the survivors of the other boys brought suit against the United States under the Federal Tort Claims Act. The district court rendered summary judgment in favor of the United States and appellants have taken this appeal under 28 U.S.C. § 1291. They contend that the district court erred in refusing to recognize their claims for injury and wrongful death. They allege that the federal government was liable for (1) the construction of the dam with a defective design; (2) the negligent care, operation and maintenance of the facility; and (3) the failure to warn of the dangerous nature of the project.
II
The Federal Tort Claims Act authorizes suits against the United States for damages “under circumstances where the United States, if a private person, would be liable to the claimant in accordance with the law of the place where the act or omission occurred.” 28 U.S.C. § 1346(b).
The Act does not, however, entirely waive the sovereign immunity of the *1052United States. The federal government may only be held liable for damages caused by the negligent or wrongful act or omission of a government employee. 28 U.S.C. § 1346(b); Logue v. United States, 412 U.S. 521, 525-26, 93 S.Ct. 2215, 2218, 37 L.Ed.2d 121 (1973). Suits against the government arising in strict or absolute liability for ultrahazardous activities are not actionable. Laird v. Nelms, 406 U.S. 797, 799, 803, 92 S.Ct. 1899, 1900, 1902, 32 L.Ed.2d 499, reh’g denied, 409 U.S. 902, 93 S.Ct. 95, 34 L.Ed.2d 165 (1972); Dalehite v. United States, 346 U.S. 15, 44-45, 73 S.Ct. 956, 972, 97 L.Ed. 1427 (1953); Thompson v. United States, 592 F.2d 1104, 1107 (9th Cir.1979).
Ill
With reference to the construction and design of the dam, appellants have failed to adduce any evidence that due care was not used. The government has, however, presented evidence that the dam was correctly designed for its purpose. Summary judgment in favor of the appellee was, therefore, proper as to this issue.
As to negligence alleged in the care, maintenance and operation of the project, these matters were transferred to the Association by the United States in the 1917 and 1935 contracts. The contracts were executed pursuant to 43 U.S.C. § 499. Section 499 states:
Whenever any legally organized water-user’s association or irrigation district shall so request, the Secretary of the Interior is authorized, in his discretion, to transfer to such water-users’ association or irrigation district the care, operation, and maintenance of all or any part of the project works, subject to such rules and regulations as he may prescribe.
Appellants have failed to adduce facts sufficient to challenge this transfer. The 1917 and 1935 contracts did not reserve to the government any ultimate duties over care, operation and maintenance. These agreements granted the United States no more than the right to inspect the project and terminate the agreements. The agreements were never terminated.1 Indeed, the government obtained hold-harmless agreements from the Association.
Liability for duties delegated pursuant to statute is forbidden. Among the classes of claims exempted from the Tort Claims Act is
[a]ny claim based upon an act or omission of any employee of the Government, exercising due care, in the execution of a statute or regulation, whether or not such statute or regulation be valid____ 28 U.S.C. § 2680(a).
The purpose of this provision is to bar “tests by tort action of the legality of statutes and regulations.” Dalehite, 346 U.S. at 33, 73 S.Ct. at 966. No evidence has been introduced which indicates that due care was not used in the transfer to the Association. The failure by the government to erect barricades or to post warnings is not, therefore, actionable, because a lawsuit concerning these omissions would represent a challenge to the statutory authority of the government to transfer full care, operation and maintenance.2
IV
The government, having validly transferred operation, care and mainte*1053nance, is also not liable for any acts or omissions of the Association. The liability of the United States extends only to the negligence of employees. 28 U.S.C. §§ 1346(b), 2671; United States v. Orleans, 425 U.S. 807, 814, 96 S.Ct. 1971, 1976, 48 L.Ed.2d 390 (1976). A contracting party is an employee if, unlike the Association, it is subject to day to day supervision. See Orleans, 425 U.S. at 815, 96 S.Ct. at 1976. That a contracting party is maintaining property owned by the federal government is irrelevant to employee status. See Thompson, 592 F.2d at 1107.
V
Because liability for properly delegated duties is forbidden under the Tort Claims Act, any tort liability of the United States must reside in some non-delegable duty under Arizona law. This court has previously recognized, under California and Nevada law, the existence of a non-delegable duty to exercise reasonable care in seeing that inherently dangerous work, which an independent contractor has agreed to perform, is performed in a non-negligent manner. See Rooney v. United States, 634 F.2d 1238, 1244 (9th Cir.1980); McGarry v. United States, 549 F.2d 587, 590 (9th Cir.1976), cert. denied, 434 U.S. 922, 98 S.Ct. 398, 54 L.Ed.2d 279 (1977); Thorne v. United States, 479 F.2d 804, 808 (9th Cir.1973). In this case, the injuries did not arise from any special dangers inherent in the actual maintenance or operation of the dam for the purpose for which it was intended. Cf. Rooney, 634 F.2d at 1240, 1244 (employee injured in fall while painting a fifty-five foot high radome); McGarry, 549 F.2d at 589-90 (employee electrocuted while preparing to drill an exploratory hole); Thorne, 479 F.2d at 805 (employee injured in construction of a dam spillway). Even if the care, maintenance and operation of the dam assumed by the Association were construed to include a duty to warn the public away from the dam, such warnings, if given, would permit the dam to be operated safely. The operation of the dam cannot then be viewed as “inherently dangerous” for purposes of rendering the United States liable, because it does not involve “a risk of harm which cannot be eliminated by the exercise of reasonable care.” Bible v. First National Bank of Rawlins, 21 Ariz. App. 54, 57, 515 P.2d 351, 354 (1973).
Judgment affirmed.
. The dissent relies upon a national 1948 agreement between several agencies of the federal government that provides for Forest Service administration of "lands in a reclamation withdrawal which are not in actual use in connection with reclamation works." In our view, that language refers to administration of land not yet used for reclamation structures. Once the diversion dam was built, the land used in connection with that dam was in actual use and the Forest Service's duty to administer it ceased. The land continues to be actually used by the diversion dam, whether or not the diversion dam continues to be in active use.
. We do not reach the question of whether, absent the bar imposed by 28 U.S.C. § 2680(a), the government would have had any duty under Arizona law as a landowner or builder either to maintain the premises in a safe condition or to warn of a dangerous condition. See Morris v. United States, 521 F.2d 872, 874 (9th Cir.1975) (If a tort claim falls within an exception delineated in 28 U.S.C. § 2680, the court lacks subject matter jurisdiction).