into ax and adz.

There seems to be a fall of about 22 feet between A at the upper
dam and B at the discharge from the troughs.[24] This fall in a
distance of about 3,000 feet seems needlessly great; however, the
primitive engineer has shown excellent judgment in the matter. First,
by putting the dam (upper dam) where it is, only half the stream had
to be built across. Second, there is a rapids immediately below the
dam, and, had the Igorot built his dam below the rapids, a dam of the
same height would have raised the water to a much lower level; this
would have necessitated a canal probably 10 or 12 feet deep instead
of three. Third, the height of the water at the upper dam has enabled
him to lay the log section of the waterway above the high-water mark
of the river, thus, probably, insuring more or less permanence. Had
the dam been built much lower down the stream the troughs would have
been near the surface of the river and been torn away annually by
the freshets, or the people would be obliged each year to tear down
and reconstruct that part of the canal. As it now is it is probable
that only the short dam will need to be rebuilt each year.

All dams and irrigating canals are built directly by or at the expense
of the persons benefited by the water. Water is never rented to persons
with sementeras along an artificial waterway. If a person refuses
to bear his share of the labor of construction and maintenance his
sementeras must lie idle for lack of water.

All sementera owners along a waterway, whether it is natural or
artificial, meet and agree in regard to the division of the water. If
there is an abundance, all open and close their sluice gates when they
please. When there is not sufficient water for this, a division is made