Neb. Rev. Stat. § 46-522

If the Chief Water Officer shall find from the evidence that the protesting petition is signed by the requisite number of owners of lands, the Chief Water Officer shall forthwith dismiss the original petition praying for the creation of the district. The finding of the Chief Water Officer upon the question of the genuineness of the signatures, and all matters of law and fact incident to such determination, shall be final and conclusive on all parties in interest whether appearing or not.