(2) The commissioners shall proceed to view the premises and determine the value of all lands within or without the district to be acquired and used for rights of way, holding basins or other works set out in the plan for reclamation. They shall assess the amount of benefits and the amount of damages, if any, that will accrue to each parcel of land, including irrigated lands, irrigation ditches and canals which contribute to the swampy, wet or overflowed condition of those lands, or any lands, public highways, railroads and other rights of way, roadways and other property which will be affected by the proposed reclamation work.

(3) For the purpose of determining benefits under the provisions of this section, all irrigated lands having an available water supply for irrigation that are adjacent to and on a higher level than other lands within the district and which fall naturally within the same watershed as the land within the district, shall be deemed contributing to the wet, swampy or overflowed condition of the lands of the district, and shall be deemed benefited by the construction of the works as specified in the plan for reclamation.

(4) The commissioners shall give due consideration and credit to any other drains, ditches, levees or other systems of reclamation which already have been constructed and which afford partial or complete protection to any tract or parcel of land in the new district.

(5) The public highways, railroads and other rights of way, roadways and other property shall be assessed according to the increased physical efficiency and decreased maintenance cost thereof by reason of the protection to be derived from the proposed works and improvements.

(6) The commissioners shall have no power to change the plan for reclamation.

(7) The commissioners shall prepare a report of their findings, which shall be signed by at least a majority of the commissioners and filed in the office of the county clerk of the county in which the district is organized. The secretary of the board of supervisors shall accompany the commissioners while engaged in their duties, and shall perform all clerical work of the board. The commissioners shall report to the board of supervisors the number of days each was employed and the actual expenses incurred. Each commissioner shall be paid $5 per day for services, and necessary expenses in addition thereto.