C153379 Feasibility Study

• Contract/PO #: C153379
• Contractor Name: Brook Forest Water District
• Contract Type: Loan
• Water District: 9
• County: Jefferson
• Bill Number: SB 80-67
• Loan Projects - Doc Type: Feasibility Study

C. HISTORICAL DEVELOPMENT OF WATER

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The presence of the Rocky Mountains has a dramatic impact on the climate

of Colorado. These mountains also exert a primary influence on the winter

moisture supply from the prevailing westerly weather system movements.

Weather systems from the Gulf of Mexico, which provide the moisture supply for

the intense thunderstorms that cause major floods in eastern Colorado, are

confined to the plains by the mountains. As moist air moves eastward from

the Pacific Ocean, it is forced upward by the Rocky Mountains, causing con-

densation and precipitation on the windward side. Having lost much of its

water content, the air descends the eastern slope, warming in the process,

thereby giving eastern Colorado a climate that is normally warm, dry and

semi-arid. This is illustrated by annual rainfall varying from 20 inches in

the mountains to 10 inches in the plains, by snowfall varying from 200 inches

to 40 inches and by annual runoff varying from 20 inches to 1 inch. The

highest average monthly streamflows occur in May and June due to snowmelt from

the mountains, however, the peak flood flows, which occur most frequently in

the same months, originate from intense thunderstorms. The remainder of the

year, streamflows result from snowmelt, rainfall runoff and groundwater

discharge.

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The first significant use of water in Colorado began with the practice of

placer mining. With such use, a system of water rights evolved which was

patterned after common law and statutory law regarding a miner's claim. A

pure appropriation doctrine of water rights developed, not initially based on

land ownership, but on the date of initia.tion of beneficial use. Thus, the

concept in water law of "first in time, first in right" was developed in

Colorado.

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Due to mining in the mountains and to early settlement patterns, the
first water users in the mountain foothills generally became the more senior
holders of direct flow water rights; those farther east became the more
junior holders of direct flow and storage water rights. As increased agri-
cultural development occurred on the plains, surface water diversions were
made as needed until complete streamflow depletion occurred during dry years.

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