16 BULLETIN 115, TJ. S. DEPARTMENT OF AGRICULTURE. 
JACKSON DITCH HEADING, COLORADO. 
The concrete and steel structure shown in Plate III, figure 2, was 
constructed in 1909, 8 miles above Fort Collins, Colo., on the Cache 
la Poudre Eiver. A low diversion dam raises the river water high 
enough to supply the demands of the Jackson Ditch, which carries 
about 75 second-feet of water. The gate shutter is of sheet steel 
operated by double rack stems, connected by a bar which turns both 
pinions at once. In front of the slots for this gate is a set of auxiliary 
slots for the insertion of flashboards in case it is necessary to remove 
the steel gates for repairs during the operating season. This feature 
can be adopted to advantage in many gates. The sand sluice adjoins 
the ditch gate. The operators state that it works well but is supple- 
mented by another sand gate a few rods below the diversion gate. 
In other parts of the West an installation similar to this has been 
more cheaply constructed by making the sand sluice merely a de- 
pression in the diversion weir, controlled with flashboards, which 
may be pulled during high water and replaced when the full height 
of the weir is needed, which occurs at a time when less sand is running 
in the stream. The total cost of the weir and gate structure was about 
$600. The concrete was mixed by hand in a ratio of one part cement 
to six parts of sand and gravel mixed. 
NAPESTA DITCH & RESERVOIR CO. HEADING, COLORADO. 
The heading of the Doyle Arroyo feeder of the Napesta Ditch & 
Reservoir Co., located on Doyle Arroyo, in Pueblo County, Colo., is 
out on the plains 21 miles below Pueblo (fig. 1). 
These arroyos in the vicinity of Pueblo are subject to sudden and 
very violent rushes of water, being dry for months at a time and then 
carrying a river of water for a short period. The only possible use of 
such water from an irrigation standpoint is to divert a large head for 
a short time and store the water in a reservoir. The object of this 
heading was to divert 850 second-feet of water from a vertical-sided 
wash, or arroyo as it is known locally. The sides and bottom of this 
wash are in shale where there is little danger of seepage under the 
structure, but it was necessary to protect the bottom of the wash 
above and the canal below the gate by a concrete apron, as the water 
was to be delivered under a head of several feet, through undershot 
gates, where the resulting velocity and scour would be very heavy. 
There are no sand sluices in connection with this heading, as there 
is little or no sand in the water, but the water is very heavy with 
adobe silt in suspension, which is carried on into the reservoir. 
As shown in figure 1, water is checked up by a low-diversion dam 
extending across the arroyo. As the spring and flood flow of this 
wash is estimated at 3,000 second-feet and it is only 50 feet wide, 
