Whenever the bonds of any irrigation district have been certified, as provided in this chapter, no expenditures shall be made from the proceeds of such bonds, nor shall any liability chargeable against such proceeds be incurred, until there shall have been filed with and approved by the director of ecology a schedule of proposed expenditures in such form as said director shall prescribe, and no expenditures from the proceeds of said bonds shall be made for any purpose in excess of the amount allowed therefor in such schedule without the written consent of said director: PROVIDED, FURTHER, That, if it shall be necessary, the attorney general may employ competent attorneys to assist him or her in the performance of his or her duties under this chapter, said attorneys to be paid by the irrigation district for which services are rendered from any of the funds of said district at such time and in such manner as the attorney general shall require.