Parameter Class

Detailed Documentation

Example Usage

General

Parameter objects are named objects that indicate abstract or physical elements subject to measurement, computation, or estimation.

Required Information

• name

• unit

Notes

Parameter names comprise a base parameter name and an optional sub-parameter name. If the name is hyphenated, the portion before the first hyphen is the base location name and the portion after the first hyphen is the sub-location name.

Base Parameters

Base parameter names are constrained to entries in the resrouces/base_parameters.txt file in the module installation directory. When the module is installed, the file contains information shown in the table below. You can programmatically retrieve a list of all available base parameters by executing:

from hec import Parameter
print(Parameter.base_parameters())

['%', 'Area', 'Code', 'Coeff', 'Conc', 'Cond', 'Count', 'Currency', 'Current', 'Date', 'Depth', 'DepthVelocity', 'Dir', 'Dist', 'Elev', 'Energy', 'Evap', 'EvapRate', 'Fish', 'Flow', 'Freq', 'Frost', 'Head', 'Height', 'Irrad', 'Length', 'Opening', 'Power', 'Precip', 'Pres', 'Probability', 'Rad', 'Ratio', 'Rotation', 'Speed', 'SpinRate', 'Stage', 'Stor', 'Temp', 'Thick', 'Timing', 'Travel', 'Turb', 'TurbF', 'TurbJ', 'TurbN', 'Volt', 'Volume', 'Width', 'pH']

Base Parameter Units

Parameter units are constrained to those that are compatible with the default units shown in the table below. You can retrieve a list of all units compatible for a base parameter by executing the following for a specified base parameter:

from hec import Parameter
print(Parameter.get_compatible_units(Parameter("Stor")))

['1000 m3', 'ac-ft', 'dsf', 'ft3', 'gal', 'kaf', 'kdsf', 'kgal', 'km3', 'm3', 'mcm', 'mgal', 'mile3']

Unit Aliases

Many units have aliases that can be used in place of the actual unit. You may can retrieve a list of aliases by executing the following for a specified unit:

from hec import unit
print(unit.get_unit_aliases("ac-ft"))

['AC-FT', 'ACFT', 'acft', 'acre-feet', 'acre-ft']

You can register a new unit alias by executing the following for a specified unit and alias:

from hec import unit
unit.add_unit_alias("ac-ft", "ft-acre")
print(unit.get_unit_aliases("ac-ft"))

['AC-FT', 'ACFT', 'acft', 'acre-feet', 'acre-ft', 'ft-acre']

You can unregister a new unit alias by executing the following for a specified unit and alias:

from hec import unit
unit.delete_unit_alias("ac-ft", "ft-acre")
print(unit.get_unit_aliases("ac-ft"))

['AC-FT', 'ACFT', 'acft', 'acre-feet', 'acre-ft']

Base Parameters Table

Base Parameter Name	Long Name	Description	Default English Unit	Default SI Unit
%	Percent	Ratio expressed as hundredths	%	%
Area	Surface Area	Area of a surface	ft2	m2
Code	Coded Information	Numeric code symbolically representing a phenomenon	n/a	n/a
Coeff	Coefficient	Unitless coefficient for formulas	n/a	n/a
Conc	Concentration	Relative content of a component dissolved or dispersed in a volume of water	ppm	mg/l
Cond	Conductivity	Ability of an aqueous solution to conduct electricity	umho/cm	umho/cm
Count	Count	Progressive sum of items enumerated one by one or group by group.	unit	unit
Currency	Currency	Economic value expressed as currency/money	$	$
Current	Current	Electric current flowing past a point in a circuit	ampere	ampere
Date	Coded Date-Time	Date and/or time encoded as a number	n/a	n/a
Depth	Depth	Depth of any form of water above the ground surface	in	mm
DepthVelocity	Depth Velocity	Depth Velocity	ft2/s	m2/s
Dir	Direction	Map direction specified clockwise from North	deg	deg
Dist	Distance	Distance between two points.	mi	km
Elev	Elevation	The height of a surface above a datum which approximates sea level	ft	m
Energy	Energy	Energy, work, or quantity of heat	MWh	MWh
Evap	Evaporation	Liquid water lost to vapor measured as an equivalent depth of liquid water	in	mm
EvapRate	Evaporation Rate	Rate of liquid water evaporation	in/day	mm/day
Fish	Fish Count	Fish Count.	unit	unit
Flow	Flow Rate	Volume rate of moving water	cfs	cms
Freq	Frequency	The number of cycles or occurrences per time unit	Hz	Hz
Frost	Ground Frost	Depth of frost penetration into the ground (non-permafrost)	in	cm
Head	Head	Difference between two elevations in a column of water	ft	m
Height	Height	The height of a surface above an arbitrary datum	ft	m
Irrad	Irradiance	Radiant Power on a unit area of irradiated surface.	langley/min	W/m2
Length	Length	Linear displacement associated with the larger horizontal planar measurment	ft	m
Opening	Opening Height	Height of opening controlling passage of water	ft	m
Power	Power	Energy rate, Radiant Flux	MW	MW
Precip	Precipitation	Deposit on the earth of hail, mist, rain, sleet, or snow	in	mm
Pres	Pressure	Pressure (force per unit area)	in-hg	kPa
Probability	Probability	Expected fraction of all events for a specific event	n/a	n/a
Rad	Irradiation	Radiant energy on a unit area of irradiated surface.	langley	J/m2
Ratio	Ratio	Quotient of two numbers having the same units	n/a	n/a
Rotation	Rotation	Angular displacement	deg	deg
Speed	Speed	Rate of moving substance or object irrespective of direction	mph	kph
SpinRate	Spin Rate	Number of revolutions made about an axis per unit of time	rpm	rpm
Stage	Stage	The height of a water surface above a designated datum other than sea level	ft	m
Stor	Storage	Volume of impounded water	ac-ft	m3
Temp	Temperature	Hotness or coldness of a substance based on measuring expansion of mercury	F	C
Thick	Thickness	Thickness of sheet of substance	in	cm
Timing	Timing	A duration of a phenomenon	sec	sec
Travel	Accumulated Travel	Accumulated movement of a fluid past a point	mi	km
Turb	Turbidity	Measurement of interference to the passage of light by matter in suspension	JTU	JTU
TurbF	Turbidity	Measurement of scattered light at an angle of 90+/-2.5 degrees to the incident light beam from a monochromatic light source (860+/-60 nm) (ISO 7027)	FNU	FNU
TurbJ	Turbidity	Measurement of interference to the passage of light by matter in suspension	JTU	JTU
TurbN	Turbidity	Measurement of scattered light at an angle of 90+/-30 degrees to the incident light beam from a white light source (540+/-140 nm) (EPA method 180.1)	NTU	NTU
Volt	Voltage	Electric Potential	volt	volt
Volume	Volume	Volume of anything other than impounded water	ft3	m3
Width	Width	Linear displacement associated with the smaller horizontal planar measurment	ft	m
pH	pH	Negative logarithm of hydrogen-ion concentration in a solution	su	su