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2.
(INEMATIC WAVE
Derivatlve of the futt St, Venant Equations _ tgnores dlffuslon anat
accelerat.ion Lerros i.n dyflanic equdtioo _ justified where Ldteldl
lnr row predonlnates-
The Chezy equacion is assr:rneai to be
dynamic equatlon.
e.q. V = Chn for overland ftow
v,here C is the Chezy constant
and n is the exponent (= ! for the chezy eqn)
a satisfactory exanple fot the
subcatchrDent raay be divided inao
"he
up to tO elemenrs either
overland
of
flow or of open-channef gutLer flow. Faram€lers of th;
are
model
the Chezy constant and exponent for each efenent, rhe Aisaavantage
of the modet is thar much dara (slopes, lengths, dirnension. i"r-.."n
element) and runrine are require.l, tut it srror:lc ;.;;,
to its beinq
dr.
a dlstributed noate_t. CorDpurer pacftage "ir;i;;;
effecttreiy
up to
rrrnrt.
4 elernents; so far: only trieal \dhere Oi"tsiin i"to .f.r"it"
closely natches real.ity.
3. TIME OF EIIIRY
TradiLional model
lhe irput tblough
the iime of entry.
used in design.!n the U.K.
a l-inear t*ne-area dtagra0,
ra infall
Equivalent to rouring
of time base equat to
Fure trans]ation, no dynamic storage