Whether the improvement is initiated by petition or resolution, the county legislative authority shall conduct a public hearing at the time and place designated in the notice to the property owners. At this hearing the authority shall hear objections from any person affected by the formation of the local district and may make such changes in the boundaries of the district or such modifications in plans for the proposed improvement as are deemed necessary: PROVIDED, That the authority may not change the boundaries of the district to include property not previously included therein without first passing a new resolution of intention and giving a new notice to property owners in the manner and form and within the time herein provided for the original notice.
After said hearing the county legislative authority has jurisdiction to overrule protests and proceed with any such improvement initiated by petition or resolution: PROVIDED, That the jurisdiction of the authority to proceed with any improvement initiated by resolution shall be divested by protests filed with the clerk of the authority prior to said public hearing signed by the owners, according to the records of the county auditor, of at least forty percent of the area of land within the proposed local district. No action whatsoever may be maintained challenging the jurisdiction or authority of the county to proceed with the improvement and creating the local district or in any way challenging the validity thereof or any proceedings relating thereto unless that action is served and filed no later than thirty days after the date of passage of the resolution ordering the improvement and creating the local district.
If the county legislative authority finds that the district should be formed, it shall by resolution order the improvement, adopt detailed plans of the local district and declare the estimated cost thereof, acquire all necessary land therefor, pay all damages caused thereby, and commence in the name of the county such eminent domain proceedings and supplemental assessment or reassessment proceedings to pay all eminent domain awards as may be necessary to entitle the county to proceed with the work. The county legislative authority shall proceed with the work and file with the county treasurer its roll levying special assessments in the amount to be paid by special assessment against the property situated within the local district in proportion to the special benefits to be derived by the property therein from the improvement.