Glossary

• Title: Glossary of CDSS Terms
• Description: Glossary of terms used throughout the CDSS documentation.
• Decision Support - Doc Type: Report
• Date: 7/5/2005
• DSS: All
• Basin: Statewide
• Prepared By: CWCB

The subordinate officers under the state engineer for each water division of the state, who performs
the functions of the state engineer in those water divisions. (Rice (1991))
DMI -Data Management Interface
A program module that provides a data transfer mechanism between the database and models.
Double Mass Curve
A curve used to adjust data when a station taking data is moved or altered. This curve is calculated
using one independant station and one or more representative stations. The representative stations
are normaly stations that are in the immediate vicinity of the station of interest and an average value is
graphed. The representative station is plotted on the y-axis and the other stations are plotted on the x-
axis. Adata point is defined by the independant value versus the average value at a point in time. If
data is good there will be a distinguishable break in the data. One line (with one slope) is drawn up to
the break and another line (with another slope) is drawn from the break to the end of the period of
record. One or the other parts of the graph can then be adjusted based on the slope ratio. (McCuen
(1989))
Due Diligence
The effort necessary to bring an intent to appropriate into fruition by the actual application of water to
the beneficial use intended. Due diligence does not require unusual effort or expenditures, but only
such constancy in the pursuit of the undertaking as is usual with those in like enterprises. Actions
which demonstrate a good faith intention to complete the undertaking within a reasonable time. (Rice
(1991))
Effective Precipitation
Effective precipitation is precipitation (rain and/or snow) falling during a growing period which meets a
portion of the crop's water requirement. Effective precipitation does not include precipitation not used
by crops composed of surface runoff and/or deep percolation past the root zone.
Effective Rainfall
See effective precipitation.
Enlargement
A subsequent right awarded to a ditch or structure enlarging the amount granted originally. More than
one enlargment may be awarded to a ditch or structure and each enlargement will have a priority
related to the date it was appropriated to beneficial use. Enlargements may be absolute or conditional.
(Rice (1991))
ER -Entity Relationships
A description of database or other "object" data in which component parts are linked.
Evaporation
Evaporation is the physical process by which a liquid is transformed to the gaseous state, which in
irrigation usually is restricted to the change of water from liquid to gas.
Evapotranspiration
Evapotranspiration is the combined process by which water is transferred from the earth's surface to
the atmosphere; evaporation of liquid water plus transpiration from plants.
Floodplain
An area adjacent to a stream or other water course which is subject to flooding. (Rice (1991))
Flow Duration Curve
A curve which plots a list of ordered data (greatest to least) against the percent of time each value is
exceeded. Used to analyze stream flows. (Chow (1964))
Forfeiture
The loss of a water right based on its nonuse for a statutorily provided period of time. (Rice (1991))
FORTRAN
"FORmula TRANslator". A computer programming language typically used for scientific programs.
Standardized as ANSI FORTRAN 77 (1977) and ANSI FORTRAN 90 (1990).
Futile Call
A situation in which a junior priority will be permitted to continue to divert in spite of demands by a
senior appropriator in the same water shed, because to curtail the junior from diversion would not
effectively produce water for beneficial use for the senior. (Rice (1991))
Gage