IRRIGATION IN NORTHERN COLORADO. 3 
In 1870 occurred two events of great importance in the develop- 
ment of the valley. The first was the completion of the Denver Pa- 
cific Bailroad from Cheyenne to Denver, which afforded a safe and 
quick means of travel from the East and solved, to a great extent, 
the problem of supplies. The second was the establishment of the 
Union Colony in the vicinity of the present town of Greeley. 
The first work of this colony was the construction of the Greeley 
Canal No. 3 to water the town site and the lands adjoining. 1 In the 
fall of 1870 work on the Greeley Canal No. 2 was started, and water 
was carried in the canal the following spring. The Greeley Canal 
No. 2 is notable for the fact that it is the first large canal built by 
community effort in Colorado and also the first built to water ex- 
tensive areas of bench land. Mistakes were made in the design and 
construction of these canals and the cost was many times the esti- 
mated amount, but the colonists kept fighting against disheartening 
odds and were finalty rewarded by success. 
The success of the Greeley colony in canal building was such that 
construction by corporations or community effort soon almost entirely 
supplanted individual effort, and by 1882 practically all the large 
canals of the valley had been built. 'Since 1882 the development has 
consisted of extensions of canals already constructed, the construction 
of ditches to bring water across from other drainage basins, and the 
building of the reservoir systems of the valley made necessary by the 
diversification of crops to include those requiring late irrigation. 
METEOROLOGY. 
Meteorological records have been taken at the State Agricultural 
College at Fort Collins for many years and are complete beginning 
with 1887. (Fig. 1.) While there is a slight variation in climatic 
conditions over the valley proper, due to a gradual transition from 
a plains to a foothill climate, this difference is so small as to be of 
no significance so far as irrigation is concerned, and the Fort Collins 
records may be taken as representative of the whole valley. They 
show the chief characteristics of the climate to be a light rainfall, with 
correspondingly few stormy days and much sunshine, a wide range 
in daily and seasonal temperature, low relative humidity, a moder- 
ate^ 7 high wind movement, and a comparatively low rate of evapora- 
tion. In Table 1 is given a summary of 31 years of the Fort Collins 
records. 
1 See Second Biennial Report, State Engineer of Colorado, 1883-84, by Col. E. S. 
Nettleton. Also History of Greeley and the Union Colony, by David Boyd. Also History 
of Larimer County, by Ansel Watrous. Also University of Colorado Historical Collec- 
tions : The Union Colony at Greeley, 1869-1871, by James F. Willard. 
