Module Discharges

Overview

Module Discharges handles all the point discharges in Mohid Water Modelling System. These discharges can be simple water discharges but can also have properties such as substances concentration (temperature, salinity, nutrients, contaminants, etc) and/or momentum.

Main features

Location

Horizontal

A discharge can be made in a point, along a line or in a polygon. The keyword to define the type of horizontal emission is SPATIAL_EMISSION, the options are: Point, Line and Polygon. The default option is Point.

SPATIAL_EMISSION : Point

A point can be define using the grid coordinates (COORD_X, COORD_Y)

COORD_X : 8.6
COORD_Y : 42.3

or specifing the cell (I_CELL - line, J_CELL - column)

I_CELL : 23
J_CELL : 43

To define a discharge along a line is necessary to specify a file with the Lines format. The keyword used is SPATIAL_FILE.

SPATIAL_FILE : Discharge.lin

To define a discharge in a box is necessary to specify a file with the Polygon format. The keyword used is SPATIAL_FILE.

SPATIAL_FILE : Discharge.xy

Vertical

VERTICAL_DISCHARGE - this keyword is used to specify the discharge distribution in the vertical direction:

1 – discharge in the bottom cell
2 – discharge in the surface cell
3 – discharge in the cell that intersects the depth defined in the keyword K_DEPTH (no default value). It is a depth relative to the water surface.
4 – discharge in the layer defined in the keyword K_CELL (no default value)
5 – Assumes a uniform distribution along the entire water column

Option 4 is the default one.

Discharge type

The discharge type is defined by the keyword

DISCHARGE_TYPE : 1

The discharge can have four possible types:

1 - normal (default)
2 - flow over
3 - valve
4 - OpenMI link 

DISCHARGE_TYPE

normal: In this case the flow is define by the user: constant value or a time serie

flow over: This discharge type aims to simulate the flow associate to a spillway. The flow in this case is function of the water level. The spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically being the river that was dammed. In the UK they may be known as overflow channels

Failed to parse (unknown error): Q=\sqrt{2g}\cdot w_{c_{_}}{\cdot }\Delta H \cdot w_{L}

valve: This discharge aims to simulate the flow associate to a hydraulic valve. The flow in this case is function of the water level difference between two locations. In this type of discharge it is necessary to define two points this way is possible to compute the

User manual

Sample discharge

MOHID WATER

Here's what a configuration file of the Module Discharges should look like for a single river run-off. Note that you are previously required to build a time serie .srw with the flow, the temperature and the salinity in order to correctly implement the discharge.

<begindischarge>
NAME                    : Loire
DESCRIPTION             : Daily timeserie for the year 2004
I_CELL                  : 144
J_CELL                  : 220
K_CELL                  : 38
DEFAULT_FLOW_VALUE      : 300
DATA_BASE_FILE          : M:\Biscay\GeneralData\Level2\rivers\Loire.srw
FLOW_COLUMN             : 2
TIME_SERIE_COLUMN       : 1
DISCHARGE_UNIFORM       : 1

<<beginproperty>>
NAME                    : temperature
UNITS                   : celcius
DESCRIPTION             : temperature in the tagus river
CONSTANT_CONC           : 0
DEFAULTVALUE            : 19.9
TIME_SERIE_COLUMN       : 3
<<endproperty>>

<<beginproperty>>
NAME                    : salinity
UNITS                   : psu
DESCRIPTION            : salinity in the tagus river
CONSTANT_CONC          : 1
DEFAULTVALUE           : 0.01
<<endproperty>>

<enddischarge>

MOHID RIVER NETWORK

For Mohid River Network discharges can be made on nodes. As so, you will need to check within the drainage network difinition in which node to discharge. Here's what a configuration file should look like for a single discharge. Note that you are previously required to build a time serie with the flow, and any other property in order to correctly implement the discharge.

Discharges into MOHID River Network can be automatically linked to SWAT model discharges; see description in SWATLink download package in www.mohid.com

Steps after creating the discharge time serie (with time and flow as minimum):

1 - Have to activate module discharges so that Discharges_X.dat in input data file appears in the simulation (in Simulation Properties add the model if not present)

2 - The block <begindischarge> <enddischarge> has to appear in Discharges_X.dat and can add the number of discharge properties that you want (or none, if only water discharged).

<begindischarge>
NAME                          : NODE_19
DESCRIPTION                   : Not given
NODE_ID                       :  19
DATA_BASE_FILE                : ..\..\GeneralData\Discharge.dat
FLOW_COLUMN                   :  2
<<beginproperty>>
NAME                          : nitrate
UNITS                         : mg N/l
DESCRIPTION                   : nitrate
TIME_SERIE_COLUMN             : 3
<<endproperty>>
...
<enddischarge>

To know the node ID of your discharge, do a query on the GIS, on top of the drainage network in the point required. The query result (if pointing to a river section) will say the node ID.

DATA_BASE_FILE is the file that was prepared with at least time and flow. If giving also property timeserie (e.g nitrate) also need a column to nitrate in the file. FLOW_COLUMN is the column with flow and TIME_SERIE_COLUMN is the column with the property time serie.

3 - have to activate discharges (DISCHARGES : 1) in DrainageNetwork_X.dat

4 - run the simulation and compare flow results in HDF or in node timeseries between a simulation with the discharge and without it (the discharge will only appear in the node timeseries results that are downstream of the inputed discharge).