WSP01765

• File Number: 8131.600
• Description: Southeastern Colorado Water conservancy District - SECWCD
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 1/1/1972
• Title: Brochure No 7 - Scientific Water Management Arkansas Valley Colorado - 1969-2050 -- The Future of the Arkansas Valley is It's Water---
• Water Supply Pro - Doc Type: Report/Study

of the Southeastern Colorado Water Conservancy
District, 905 Highway 50 West, Pueblo, Colorado, or
from the nearest Office of the U. S. Geological Survey.

GLOSSARY OF SELECTED WATER TERMS

AQUIFER . A porous water.bearing geologic fonnation.
AREA, INFLUENCE . The surFace area surrounding a well,
or group of wells, during pumping, within which the water
table or other piezometric surface is lowered by withdrawal of
the water. The area \'aries in extent with the rate and duration
of pumping.
BEDROCK Any solid rock underlying ~il. sand, clay. silt.
elc.

CAPACITY. MOISTURE. FIELD. The approximate quantity
of water which can be J'ennanently retained in the soil in op-
position to the downwar pull of gra\'ity. It may he expressed in
percent of dry weight or in inches depth for a given depth of
soil. The lenF;th of time required for a soil to reach field
moisture capacity varies considerably with \'arious soils, being
approximately 24 to 48 hours for sandy soils, 5 to 10 days for
silt clay soils. and longer for clays. Also called capillary capacifJ,
field carryiJ1g capacity, maximllm water holding. capacit)., moist-
ure holding capacity, and J10rmal moisture capacity. See reten-
lion, specific; capacity, field.

CAPACITY, WELL - The maximum rale at which a well will
yield water under a stipulated set of conditions. such as & given
drawdown, pump and motor 01 engine !Oil.e. It may be ex-
pressed in terms of gallons per minute, cubic feel per second. or
other similar unils.

CYCLE, HYDROLOGIC. The circuit of water mo\'ement from
the almosphere to the earth and return to Ihe atmosphere throu8h
various stages or processes as precipitation, interception, runoff.
infiltration, percolation, storage, e\'aporation and transpiralion.

DEPLETION . (I) The continued withdrawal of water from
a surface or ground-water stream, reservoir. or basin at a rate
greater than the rale of replenishment. (2) In appraisal work
the quantitative exhaustion of natural resources, usually in con-
nection with commercial exploitation and usually recorded in
monetary lenns.

FLOW, RETURN. Any flow which relurns to a stream chan-
nel after di\'ersion for beneficial use or other purposes. In irri.
gation. water applied to an <Irea which is nOI consumed in
evaporation or transpiration, and retum'i to a sutface stream or
ground-waler aquifer.
HYDROLOGY - The applied science concerned with the waters
of the earth in all its slates - their occurrences, distribution. and
circulation through the unending hydrologiC cycle of: lrecipita-
tion; consequent runoff, stream flow, infiltration, an sloragei
eventual evaporation; and reprecipilCltion. It is concerned with
the physical. chemical, and physioloRical reactions of waler with
the rest of the earth, and its relation lO the bfe of the earth.
HYDROLOGY, GROUND-WATER The b"och of hydml,
ogy that treats of ground wateri its occurrence and mo\'emenISi
ils re(llenishmenls and depletion; the properties of rocks that
control ground-water movement .md storage; and the melhods of
im'estigation and U1ilization of ground water.
INFLUENCE, COf\:E OF - The depression, roughly conical in
shape. produced in a water table, or olher piezometric surface.

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by the extraction of water from a well at a Ji[iven rate. The
volume of the cone will vary with the rate of withdrawal of
water. Also called cone of depression.
LOG, WELL - A chronolo.'!;ical record 01 the soil a.nd rock
formations which were encountered in the operation of sinking
a well, with either their thickness, or the cle\'ation of the lOp
and ooltom of each formation gi\'en. It <ll~ u~ually includc~
st<ltcments a~ to the litholllJil:ic composition und w..Ller-be.lring
characlerislics of each formation.
METHOD, ELECTRICAL-ANALOGY. A method by which
the phenomena 'pertaining to one physical system. such as flow
of water through porous media, are studied by e:'l.pcrimcnts in
another physical sySlem, namely the flow of electricity through
conductors. It is employed for the solution of problems in dif.
ferent fields such as stress analysis of dams or machine parts by
Ihe pholoelastic method, estimalion of water levels in ti,bl nel-
works. piping and uplift in the desll<(n of structures on permcable
foundations. torsion of shafts, ca\'itation around streamlined
bodies as air~hips. torpedos, heat transfcr in the ucsiJi[n of fur'
naces and imernal combustion enRines. etc.
OVER-DEVELOPMENT - In ground wateri when the eco-
nomic yield of an aquifer is exceeded, that aquifer is said to be
overde\'e1oped. If the trammissibilit)' of an aquifer is limited.
excessi\'e wilhdrawals in a restricted area may cause sufficient
drawdown locally as to make it uneconomic to continue to
withdraw \Valer at that rate, e\'en though the physical yield
limit for the emire aquifer has not been reached. That condilion
is called local ot.'er-~et.'elop'nell!.
PERMEABILITY. The properlY of a material which permits
appreciable mO\'emeor of water Ihrough it when saturated and
actuated by hydrostatic pressure of the magnitude normally. c;n-
countered in natural subsurface water. The rate of penneabillty
is measured by. the quantity of water passing through a unit
cross !Oection. in a unit time when the gradient of the energy
head is unilv. Pret.'ioIlSlJess is !oOmetimes used in the same sense
as renneabillty. See coefficiePlt, permeability.
POROSITY - (I) The state of being porous or containing in.
terstices. (2) An index of the void characteri!Otics of a soil or
stratum as penaimng to percolation; degree of perviousness. (3)
The ralio, usually expressed as a percentage. of (a) the volume
of the interstices in a gi\'en quantity of material, to (b) the
total \'olume of soil or rock.
PRECIPITATION - (I) The total measurable supply of water
of all fonns of falling moisture, including dew, rain, misl, snow,
hail. and sleet; usually expressed as depth of liquid waler on a
horizontal surf::Jce in a dar' momh. or year, and designated as
daily, monthl)', or annua precipitation. (2) The process by
which atmosphetic moisture in li~ui.d or solid state is discharged
onto a land Ot water surface. (3) The phenomenon which oc-
curs when a substance held in solution in a liquid passes OUI
of solulion into solid form.
REOUIREMENT, WATER - The tOlaI quantity of water, re-
gardless of its source. required by crops for Iheir nonnal growth
under field condilions. It may include water applied in irriga-
tion. precipitation. and ground \\-'ater available to the crops.
RESERVOIR, GROUND-WATER. (I) A ....rvoir in which
ground-waler is stored for future eXlCaction and use. The water
may be placed in the reservoir by anificial means (spreading.
etc.) or. by natural means (seepage, infiltration, etc.). (2) See
acquifer.
SPREADING, WATER - (I) The artificial application of
water to lands for the purpose of storing it in the ground for
subsequenl withdrawal by pumps for crops. (2) Irrigation by
surplus waters out of cropping season.

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