Provision shall be made for the collection of all sums expended by the state under this chapter and their return to the state is not to exceed ten (10) annual installments, said installments to be collected and returned to the state at the same times and in similar manner as may be provided for the collection of the installments due to the national government. Such installments when returned to the state shall constitute a trust fund in the hands of the state treasurer to be used only for the reclamation of other arid lands.