FLOOD09983

• County: Statewide
• Community: State of Colorado
• Stream Name: All
• Basin: Statewide
• Title: Mudflow A Two Dimensional Hyperconcentrated Sediment Flow-routing computer Model
• Date: 3/1/1989
• Prepared For: State of Colorado
• Prepared By: Simons Li & Associates Inc.
• Floodplain - Doc Type: Educational/Technical/Reference Information

3,11

line

Vari ab 1 e~,

(R)
XKX '

The laminar flow resistance parameter for over'land flow divided by
the average Mann i ng' s n val ue for the gri d system. It is suggested
that a value of 2285 be used for XKX. This corresponds to K = 160
and an average Manning's n of .07 from Equat'ion 2.21.

(I)
KKL(I) -

Array of channel grid elements in the upstream watershed for which
a sediment concentration matrix will be specified. The channel grids
will constitute the origin of the sediment for processing the mud
flow.

(R)
CCV (ITI ,
KKL(I)) -

~
Array of sedi ment con cent rat ions by vol ume wh i ch constitute the
inflow of sediment to the watershed channel system. Corresponding
to time interval (ITI) and channel gl'id element KKL(I). (0. ~
CCV(ITI,KKL(I)) ~ 1.0).

3.2.1 Important Coments Regarding Data Input Parameters

The MUDFLOW mode has the capabil ity to analyze hyperconcentrated sediment
flows in overl and areas or in channel s. Over1 and fl ow can be s imul ated across an
uncDnfi ned all uvi a 1 fan or in a steep watershed. The watershed can be modeled to
gener,ate an outflow hydrDgraph at the fan apex that would constitute the inflow
hydrDgraph to the alluvial fan. If hyperconcentrated sediment flows are going to
be simulated set MUD = 1. If the upstream ~Iatershed is going to be util ized to
deve lop an outflow hydrograph set IUPMUD = 1.
A one,dimensional analysis can be per'formed for the channel and a two'
dimensional analysis for the flood plain using the channel,flood plain interface
routine. If a one,dimensional analysis is to be conducted, set ITER = O. For a
two,dimensional analysis without a channel, set both ITER and NODe equal to zero.
If a channel is included and a one, and two-dimensional analysis is being performed,
ITER and NODe are nonzero. The channel and flood plain routing can be performed
as either a kinematic or diffusive wave approximation using the KMODEL switch. The
following comments will assist in the developing of the data file:

1. Either the channel or the flood plain grid elements can be used to input the
inflow hydrograph to grid system.

2. The channel bottom elevation is calculated internally in the model based on
the input channel depth and the flood plain elevation.