Idaho Code § 42-2931
In any case where the work set out in the plan for drainage as provided in this chapter, or the work or improvements and the system of diking and reclamation constructed or in process of construction, are deemed or found by the board of commissioners of any drainage district at any time before or after the completion thereof to be insufficient or inadequate for any reason or by reason of any occurrence or circumstance, said board may order and cause to be done and constructed (in the manner provided and permitted by this chapter and subject to the judicial proceedings required by this chapter) additional work and improvements for the purpose of rendering sufficient and adequate the work and improvements and system of reclamation and drainage already constructed or for the purpose of reconstructing and for the preservation of the same; and also in any case where in the judgment of said board, new, additional or separate works and improvements (in the nature of original construction or reconstruction work and improvements) shall be or become necessary for the sufficient, safe and adequate drainage and reclamation of said district or for the safety and preservation of the work, improvements and system already constructed, said board may order and cause to be done and constructed such new, additional and separate works and improvements; and a new estimate of benefits may be made in each and all of said cases based on the additional or separate additional work or construction or reconstruction work proposed; and additional assessments for each or all of such additional or separate works and improvements may be made on the lands benefits in conformity with the procedure provided in this chapter as in the case of original construction; and the lands in said district, or any part of such lands, shall be assessed in proportion to the benefits estimated as accruing to such lands because of such additional or separate work and improvements or because of such separate or additional construction and reconstruction work and improvements. The provisions of chapter 29 shall apply to all proceedings had or matters or things done pursuant to the authorization of this section, the necessary substitutions and changes being made because of any variant circumstances.
Idaho Code § 42-2931