18 BULLETIN 1177, U. S. DEPARTMENT OF AGRICULTURE. 
Operation costs — Tolls. — The basis for securing revenue for oper- 
ating purposes is frequently different from that upon which con- 
struction charges are apportioned. While all irrigable (and some- 
times nonirrigable) lands in an irrigation district are made liable for 
the cost of building or acquiring the irrigation system, nevertheless 
a sentiment sometimes prevails that lands not using water should 
not be required to bear so large a proportion of the cost of main- 
taining and operating the system as lands to which water is actually 
delivered. In some States this distinction may be made in the annual 
assessment for general expenses, and in others it is made possible 
only through the imposition of tolls. 
The ad valorem method in Texas does not apply to assessments 
for maintenance and operation purposes. For such purposes, one- 
third to two-thirds of the estimated expense for each year is charged 
at a uniform rate per acre to all land capable of being irrigated and 
the balance to all persons actually applying for water. In the exercise 
of statutory authority, some of the Texas districts take promissory 
notes in advance from applicants for water and hypothecate these 
notes in order to secure money for operating expenses. 
Where assessments in Idaho districts are levied for maintenance 
and operation purposes, they are required to be in proportion to the 
benefits received from the maintenance and operation of the district 
works rather than proportionate to the construction cost. This 
makes it possible to charge general expenses in whole or in part to 
lands using water in any year. Idaho has a further provision that 
in cases where works were constructed by the United States under 
the reclamation act, operation and maintenance assessments shall be 
levied according to the number of acre-feet delivered during the 
preceding season, with a minimum charge upon each irrigable acre 
for not less than one acre-foot. 
New Mexico provides that in districts formed to contract with the 
United States, the portion of operation and maintenance costs to be 
collected by tax shall be not less than one-fourth nor more than two- 
thirds of the total. 
Most of the States give district directors the discretion of fixing 
rates of toll for water in order to defray the expenses of organization, 
the operation, repair, and improvement of canals constructed and in 
use, salaries, and other current expenses, or of levying assessments 
for such purposes, or of employing both methods. Tolls may some- 
times be made payable in advance of water delivery, but this is 
seldom done (except through the hypothecation of notes in Texas 
districts) owing to the fact that money for the payment of tolls is 
often available only upon the sale of crops which that particular 
water was used in producing. In one Idaho district the quantity of 
water used during the season is the basis of charge for water master's 
and ditch riders' salaries and for repairing an occasional break on the 
canal system, and the area of land irrigable is the basis of assessments 
for maintenance and all general expenses. Three of the older Cali- 
fornia districts which have now no bonded indebtedness derive all or 
nearly all of their income from tolls and several others use both tolls 
and assessments. 
BONDS. 
The outstanding feature that distinguished the early Wright Act 
districts from those authorized by the early Utah law was the power 
