Model help:TopoFlow-Diversions

TopoFlow-Diversions

This is the diversions component for a D8-based, spatial hydrologic model.

Model introduction

This process component is part of a spatially-distributed hydrologic model called TopoFlow, but it can now be used as a stand-alone model. TopoFlow supports three different types of flow diversions: sources, sinks and canals. Sources are locations such as natural springs where water enters the watershed at a point by some process other than those that are otherwise modeled. Similarly, sinks are locations where water leaves the watershed at a point. Canals are generally man-made reaches such as tunnels or irrigation ditches that transport water from one point to another, typically without following the natural gradient of the terrain that is indicated by the DEM. The upstream end is essentially a sink and the downstream end a source.

Input

Parameter	Description	Unit
Component status	Enabled / Disabled	[-]
Input directory	The location of the input files	[-]
Output directory	The location for the output files	[-]
Site prefix		[-]
Case prefix		[-]
Use sources toggle	Option to use sources	[-]
Sources file	source information file	[-]
Use sinks toggle	Option to use sinks	[-]
Sinks file	sink information file	[-]
Use canals toggle	Option to use canals	[-]
Canal file	canal information file	[-]

Uses ports

• Channels (surface water flow in a network of channels with trapezoidal cross-section)

Provides ports

• Diversions (sources, sinks and canals)

• Configure (tabbed dialog GUI to change settings)

• Run (only if used as the Driver)

Main equations

A list of the key equations. HTML format is supported; latex format will be supported in the future

Nomenclature

Symbol	Description	Unit
ID	source pixel ID as long integer, calendar index (for sources and sinks)	-
nd	number of durations and flow rates (for sources and sinks, cannals)	-
durations	vector of durations (for sources and sinks, canals)	T
flow rates	vector of discharges (for sources and sinks, canals)	L3 / T
ID1	start pixel ID as long integer; calendar index (for canals)	-
ID2	end pixel ID as long integer; calendar index (for canals)	-

Notes

To use flow diversions, you must provide the required information in specially-formatted text files (see examples below). Where required, vector-valued input variables such as discharges are specified as a list of space-delimited numbers on one line (i.e. terminated by a single end-of-line character). Keys that end with "_ID" refer to the integer value that is assigned to a given pixel (i.e. grid cell) when all pixels in the corresponding DEM are numbered sequentially in calendar order , that is, from top row to bottom row and from left to right within each row. Pixel IDs start at zero and are read and processed as long (4-byte) integers.

Canals are currently assumed to be lossless, so that the flow rates at the two ends are identical, but lagged by the travel time.

Format of a Sources File

A "sources" file is a plain text file that starts with 3 key-value pairs that provide information for all sources. This is followed by n_sources blocks (with 3 more key-value pairs each) which each provide information for one of the sources. The six keys are defined as follows.

n_sources is the number of sources
nt_max is the maximum number of times for which discharge values are provided (out of all the sources).
dt is the timestep between successive values.
source_ID is the long-integer, calendar-style ID of the grid cell that contains the source.
nt is the number of timesteps for the corresponding source_ID.
Discharge is the volumetric discharge that comes from the source, in units of m3/s.

Example:
n_sources: 2
nt_max: 10
dt: 0.0
source_ID: 65
nt: 10
Discharge: 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05
source_ID: 62
nt: 5
Discharge: 0.05 0.05 0.05 0.05 0.05

Format of a Sinks File

A "sinks" file is a plain text file that is identical in format and keys to a sources file, except replacing the word "source" with "sink".

Example:
n_sinks: 1
nt_max: 10
dt: 0.0
sink_ID: 65
nt: 10
Discharge: 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05
sink_ID: 62
nt: 5
Discharge: 0.05 0.05 0.05 0.05 0.05

Format of a Canals File

A "canals" file is a plain text file that starts with 1 key-value pair that provides the number of canals. This is followed by n_canals blocks (with 4 more key-value pairs each) which each provide information for one of the canals. The five keys are defined as follows.

n_canals is the number of canals
canal_in_ID is the long-integer, calendar-style ID of the grid cell that contains the upstream end of the canal.
canal_out_ID is the long-integer, calendar-style ID of the grid cell that contains the downstream end of the canal.
Q_fraction is the fraction of discharge (Q, m3/s), between 0 (none) and 1 (100%) which is to be removed from canal_in_ID and routed to canal_out_ID.
travel_time is the time, in seconds, for the flow to travel from canal_in_ID to canal_out_ID.

Example:
n_canals: 1
canal_in_ID: 216
canal_out_ID: 203
Q_fraction: 0.5
travel_time: 240.0 [seconds]

Examples

An example run with input parameters, BLD files, as well as a figure / movie of the output

Follow the next steps to include images / movies of simulations:

• Upload file: http://csdms.colorado.edu/wiki/Special:Upload
• Create link to the file on your page: [[Image:<file name>]].

See also: Help:Images or Help:Movies

Developer(s)

Scott Peckham

References

Key papers

Links

• Model:TopoFlow-Diversions
• Model:TopoFlow