WSP08828

• File Number: 8449.800
• Description: Denver Basin and South Platte River Basin Technical Study
• State: CO
• Basin: South Platte
• Date: 1/1/1984
• Author: CWCB/SEO
• Title: Notes for Ground-Water Model Presentation
• Water Supply Pro - Doc Type: Report/Study

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NOTES FOR GROUND-WATER MODEL PRESENTATIONS:

Basic Statistics:
Amount of water on the earth:
only about 3% to 6% of the water on the earth's surface is
fresh water (depending upon who the author is)
1% to 2% of the water on the earth is in glaciers and icecaps
2% to 4% of the water on the earth is ground water
of the fresh water on the earth, excluding the icecaps and
glaciers - i.e. usable fresh water, 95% is ground water, 3.5%
is surface water, and the remaining 1.5% is soil moisture
in terms of something to relate this too; if all the water on
the earth could be put into 100 I-gallon milk jugs, then 94 to
97 of them would be salt water. Using the highest figure of
6% fresh water, then 6 gallons would be fresh water. Of these
6 gallons, 2 gallons would be in the icecaps and glaciers. Of
the remaining 4 gallons (64 cups or 512 oz.), 3.8 gallons
(60.8 cups or 486.4 oz) are in the ground, 0.14 gallons (2.24
cups or 17.92 oz) are on the surface, and 0.06 gallons (0.96
cups or 7.68 oz) are in the soils. Of the 100 gallons of
water on the earth, fresh water on the surface would amount to
about a medium Taco Bell soda.

95% of the water available in the United States is in the
ground: of all the water used in the United States in 1970,
81% came from surface water supplies and 19% came from the
ground 57% was used by industry, 35 % was used for
irrigation, 7% was used for public/domestic supplies, and 1%
was for. rural domestic supplies. In the western states,
ground water accounts for 44% of the industrial supplies and
46% of the public supplies; in the eastern states ground water
accounts for 16% of the industrial supplies and 29% of the
public supplies. In the western states, there are some areas
that get 100% of their water from ground-water resources
(Denver gets between 45% and 60% of its water from ground-
water resources depending upon the time of year and the amount
of rainfall/snow fall in any given year) .

Basic Con,cepts:
porosity is a measure of the ratio of void (open) spaces in a
material to the total volume of the material. One way to look
at this is if you have a 32 oz cup from Taco Bell and you fill
it with a solid material (the ice) and then fill it with a
fluid (the soda), then the amount of fluid that the cup will
hold is a measure of the porosity of the solid material in the
cup (the ice filled cup) - which will be a lot less than the
nominal 32 oz capacity of the cup.
porosity is controlled by the sizes of the solids, the shapes
of the solids, how well sorted the solids are, and how tightly
packed the solids are. Think of having two rooms the same
size as the one you are in; fill one room with basketballs and
the ~ther with baseballs, then turn on the sprinkler system
and fill the rooms with water. Which room will hold more
water? Answer - they will both hold the same amount of water