4 
Colorado Experiment Station 
purity in the raw water is at once discovered and remedied by 
proper treatment. 
In addition to its resident chemist and regular assistants in 
the laboratory and at the filtration plants, the Company employs 
as consulting chemists and bacteriologists a number of the best 
known and most skilled water experts in the country. These ex¬ 
perts visit Denver frequently for the purpose of checking the 
work done by the filter plants and offering suggestions for keep¬ 
ing the purfication system fully abreast of the times. 
SOURCE OF SUPPLY 
The principal source of supply is Lake Cheesman, located 
fifty miles from Denver, and formed by impounding the waters of 
the South Fork of the South Platte River and Goose Creek. The 
surface area of this reservoir is 879 acres, and it has a storage 
capacity of 26,000,000,000 gallons—enough to supply Denver for 
two years without replenishment or assistance from any other 
source. From Cheesman Lake the water is carried down South 
Platte Canon in the channel of the South Platte River to the in¬ 
take of the water system, 25 miles below, and 25 miles from 
Denver. A 60-inch pipeline conveys the water from the intake 
works to Marston Lake, which can accommodate 6,400,000,000 
gallons and to Platte Canon reservoir, with a storage capacity of 
300,000,000 gallons. 
Besides the Platte River water, Marston Lake receives an 
additional supply from Bear Creek taken out above Morrison. 
Cherry Creek, thru a system of infiltration galleries, con¬ 
tributes a limited amount to the city supply. 
FILTRATION AND TREATMENT 
Three methods of purification by filtration are employed in 
connection with the Denver supply: 
1. Mechanical filtration is practiced at the Willard plant, 
which has a daily capacity of 15,000,000 gallons, and at the two 
Marston Lake plants with a combined daily capacity of 25,000,000 
gallons. The filtered water from the Willard plant is subsequent¬ 
ly treated with hypochlorite. Chlorine gas and hypochlorite are 
used at the two Marston Lake plants, respectively. 
2. An English slow sand plant located at Platte Canon with 
six filter beds having a total filtering area of 10^4 acres is capable 
of furnishing 30,000,000 gallons of filtered water daily. Prelimi¬ 
nary sedimentation is accomplished in Platte Canon Reservoir. 
Hypochlorite is added to the filtered water as needed. 
3. Infiltration galleries located near the slow sand filter beds 
and Lehow Lake, along the South Platte River above Mississippi 
