hat used by cities for general supply, for
household and drinking purposes; next, that which is used for navigation
and the running of boats to carry commerce; third, that which is used
for artificial watering or irrigation, and lastly, that which is used
for power in manufacturing.

In the past, when water has been used it has seldom been employed for
more than one of these purposes, but as we come to understand more the
nature, value and possibilities of this great resource, we shall learn
to make the money spent for one of these lines of activity supply
several other needs.

As we study each of these separately we shall see this interrelation
among them.

The cities of the United States have expended $250,000,000 in waterworks
and nearly as much more in land for reservoirs, and for canals for
conveying the water from these reservoirs to the cities. The better
managed systems protect the drained lands from erosion by planting
forests or grass and the water is completely controlled, so that all the
water, even the storm overflow, is saved. There is very little waste in
these city water systems until it comes to the consumer, where, except
when it is sold through meters, the waste is often great.

The failure to provide the greatest good lies in the fact that the
water systems have been used for water supply only and have not been
made profitable in other ways. The drainage basins should be heavily
planted with trees, which will in time yield a large return, or with
hay, which can be marketed each year. Whenever possible, the canals
carrying the water supply should also be used to furnish power.

The city of Los Angeles, when it had a population of only 150,000,
undertook to provide pure water from a point two hundred and fifty miles
distant. To do so it must take on itself a debt of $23,000,000, a large
sum for a city ten times its size. Yet the people were ready to assume
this great burden to insure an unending supply of pure water, for they
realized that without it their city could not continue to grow. It was
not until the plans for piping water to the city were almost completed
that the value of the water-power along the route was realized. It has
been disposed of at a rate that pays ten per cent. interest on the debt
each year, and has made what seemed a dangerous risk, a profitable
business arrangement. All these other uses of water which are
profitable, help to lower the price of water to the users.

The