60 BULLETIN 1201, U. S. DEPARTMENT OF AGRICULTURE. 
Buch work. One method of arriving at the reduction is to assume 
that the same ratio exists between cost and benefits of this additional 
work as exists between the cost and benefits of the work to be done by 
the district. Thus, if the total benefits of the district are three times 
the cost of the district improvement, the individual benefits as deter- 
mined for complete drainage should be reduced by a sum equal to 
three times the cost of any work which must be done by the owner 
to secure complete drainage. 
In the same way deductions can be computed for the disadvantage 
suffered by a tract which lies at a distance from the outlet furnished 
by the district. 
Where the land is subjected to a hazard due to insufficient size 
of drain or poor outlet, the benefits determined should be reduced by 
an amount based upon the estimated time during which the land will 
be overflowed and the extent of the injuries from such overflow. 
In case a tile drain is laid in an open ditch or natural watercourse 
the additional benefit due to this would be equal to the drained 
value of the newly made land. 
If it is desired to find the amount of additional benefit due to a 
ditch or tile drain crossing a tract of land, the difference in value 
between the completely drained strip and the rest of the tract should 
be determined and added to the benefits found for the entire tract. 
Where there is variation in the porosity of the soils within the dis- 
trict, the width of the- strip so drained should be considered as 
that of the most impervious soil. 
If conditions be such that it is advisable to make each lateral or 
other section of the improvement an assessment subdistrict, it can be 
done by apportioning the costs of the subdistrict, plus a proportional 
part of the outlet costs, among the lands affected by the lateral ac- 
cording to their several benefits. 
The following form has been used with success for some years in 
Wisconsin : 
Parcel No. No. of acres . Owner 
Township Range Section 
Fall to ditch No. feet. 
Acres wet land Acres medium Acres high 
Soil 
Present value per acre of wet land 
Improved value per acre of wet land_. 
Tot ;il improved value of wet land 
Total present value of wet land 
Gross benefits to wet land 
Allow for drains already constructed 
Allow for outlet 
Allow for 
Net benefits to wet land 
Dollars. 
Present value per acre of medium land 
Improved value iter acre of medium land 
Total improved value per -^rrr of medium land 
Total pi-. 'son! value per acre of medium land 
Cross benefits to medium land 
Allow for drains already constructed 
Allow for outlet 
Allow for 
Special benefits to dry land 
Nature of special benefits to dry Land 
