Section 15-1925. General apportionment of cost

1.  A  general  apportionment  of  the  cost of the complete system of
  drainage shall be made as herein described. The  total  cost  determined
  under  the  provisions of section 15-1923 shall be equitably apportioned
  on the various parcels of land  in  the  district  and  on  such  public
  corporations  as  the department may find to be justly chargeable with a
  part of such cost in addition to what might be apportioned  to  them  as
  owners  of property in the district. Such charge on a public corporation
  shall be expressed as a percentage  of  the  whole  cost  and  only  the
  remaining  percentage of the cost shall be apportioned on the individual
  properties.
    2. The general theory of such apportionment shall be that  any  parcel
  using  or served by any ditch or part of a ditch shall share in the cost
  of that ditch or part and that share  shall  be  in  proportion  to  the
  drainage  enhancement  of that parcel already determined as set forth in
  section 15-1919 as compared with the sum of such  drainage  enhancements
  of all the parcels using or served by the same ditch or part of a ditch,
  but  such  strict  rule  may  be  modified should it lead to inequitable
  results.
    3. The department may divide the whole drainage system into individual
  ditches and appropriate parts of ditches, estimate  for  each  ditch  or
  part the total cost thereof, determine the boundaries of the lands which
  would  use  or be served by that ditch or part, subdivide the previously
  determined drainage enhancement of each parcel which may  be  subdivided
  by such boundaries and apportion the total cost of each ditch or part of
  a  ditch  accordingly. Finally all amounts apportioned to any one parcel
  shall be added together and compared with the  drainage  enhancement  of
  that  parcel. Should the total cost apportioned to any parcel exceed the
  drainage enhancement of that parcel, the design of the  drainage  system
  or  the  boundaries of the district shall be changed in such manner that
  for no parcel shall the costs exceed the  enhancements.  The  department
  may  make  a  similar  apportionment  of  the  cost determined under the
  provisions of section 15-1923 for such drainage  works  heretofore  done
  which  in  its  opinion  are  useful  and  may  be incorporated into the
  complete system of drainage.