For the public purposes contemplated in La. Rev. Stat. 34:341, the commissioner of wildlife and fisheries shall endeavor to acquire the needed canals and locks by amicable agreement with the owners thereof, failing which he may expropriate the needed properties in accordance with the general expropriation laws of the state.  An agreement of purchase or lease contemplating the acquisition of the needed properties may be made by the commissioner upon a basis of annual or semi-annual installment payments bearing not more than seven per centum per annum interest with vendor’s privilege or other security clauses; he may also execute the necessary acts of purchase or lease and issue the required interest-bearing notes or evidences of indebtedness, which notes or other evidences of indebtedness shall be properly paraphed for identification with the acts of purchase or lease.  The commissioner may provide in his annual budget for the payment of the obligations so incurred.