X hits on this document

PDF document

Parameter Sensitivity in Hydrologic Modeling - page 141 / 163

644 views

0 shares

0 downloads

0 comments

141 / 163

curve number developed by automated methods as an approximate upper limit, and the curve number developed by TxDOT as an approximate lower limit, gave a coefficient of variation of 3.08%, and a mean value of 89. This number is used to reflect a reasonable error one might encounter in determining SCS curve number.

6.3

SIGNIFICANCE OF ERRORS

Following hydrologic parameter extraction, ranging from traditional methods using paper maps to advanced methods using TINs, a sensitivity analysis based on the concept of elasticity was conducted for Area 2.

Quantifying discharge elasticity with respect to parameter variation is a two-step process. The first step involves determining the variation in SCS lag time with slope, longest flow path, and curve number. Variations in parameter values using the four levels of parameter extraction were plotted against resulting

SCS

lag

time

values.

The

range

in

parameter

values,

divided

by

the

mean

parameter value, resulting SCS lag

was used to describe the times, divided by the mean

parameter variation. The range of SCS lag time, was used to quantify

the lag time variation. The lag describes the lag time elasticity

time with

variation, respect to

divided by the the parameter.

parameter variation, In other words, this

describes the percent increase that will occur in lag time parameter. If this number is less than 1, then lag time is

by a 1% increase in the “inelastic” with respect

to the parameter. If this respect to the parameter. time.

number is greater than 1, then lag time An elastic parameter will cause larger

is “elastic” with variations in lag

131

Document info
Document views644
Page views644
Page last viewedWed Jan 25 00:07:55 UTC 2017
Pages163
Paragraphs3546
Words25756

Comments