If a board determines that improvements which differ from repairs are necessary or desirable, the board may appoint an engineer to conduct a survey of the proposed improvement, estimate its cost, and file the estimate with the board. An improvement may include enlarging, reopening, widening, deepening, strengthening, or lengthening of any drain; changing the location of or improving and enlarging an outlet for better service; converting all or a part of any drain from an open ditch to a closed drain; installing surface pipe for open ditches; leveling spoil banks; or constructing settling basins. If the estimated cost of the improvements does not exceed ten thousand dollars, the board may order the work done without notice.
SDCL 46A-10A-86