Section 15-1923. Plans and estimates

The  department  may  make a study of the works necessary to drain the
  district and prepare  maps,  plans,  estimates  and  reports  showing  a
  complete  system of drainage therefor, the estimated cost of the various
  ditches and other works and parts thereof and the boundaries of the land
  which will be served by and therefor should contribute to  the  cost  of
  each structure. These estimates of costs shall be made on the assumption
  that  no  drainage  work has ever been done in the district. In addition
  the department may show  on  the  plans  any  drainage  work  which  has
  heretofore  been  done  in  the district, may estimate the cost of those
  works on the same basis used  for  the  estimate  of  the  cost  of  the
  proposed  system  and  in similar manner may determine the boundaries of
  the land served by the existing ditches.