Surface Water Routing:Introducing Dischage/Constituent Hydrographs

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Any number of point discharges can be added to the stream network using the CHAN_POINT_INPUT card in the project file. The CHAN_POINT_INPUT card specifies the name of the input file that contains the point discharge information. The point source input file is card based and very similar to the rain gage input file, Section 6.2.

The first card in the point source input file is the NUMPT card which specifies the number of point sources in the file. The NUMPT card is followed by a NUMPT number of POINT cards, which are used to specify the node number, link number, and discharge (cms) of the point source. If constituent transport is being simulated, Chapter 11, then the concentration of each point source (mg/L) must be included. The order of the constituents should be the same as specified in the MAPPING_TABLE file. For steady-state point sources this is the end of the input file.

The discharge or concentration of the point sources can also vary in time. To include varying point sources specify the number of changes with the NRPDS card. The NRPDS card is then followed by a NRPDS number of INPUT cards, which are used to specify the time (year month day hour) and updated discharges (cms), along with updated concentrations (mg/L) if simulating constituent transport. For each point discharge the concentrations follow the discharge.

Card Argument Description
NUMPT integer Number of point discharges.
POINT1
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POINTNUMPT

integer integer real

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Point node and link location, discharge (cms). Followed by concentrations (mg/L) if simulating constituents. One for each NUMPT.
NRPDS integer Number of discharge updates.
INPUT1
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INPUTNRPDS

date time val1,1..val1,NUMPT

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date time valNRPDS,1..valNRPDS,NUMPT

The number of INPUT cards must equal NRPDS. Each INPUT card must have the date and time of the recording, and be followed by NUMPT real values of discharge during that period. Each discharge is followed by constituent concentrations if simulating constituent transport.

For example, assume that two steady-state point discharges are to be added to a stream network in a standard surface water hydrology study. These point discharge could represent pumping to the stream or the addition of base flow from a groundwater model. Discharge 1 is located at node 1, link 1 and is 1.0 cms. Discharge 2 of 2.0 cms is located at node 5 link 6. For this case the input file would be:

NUMPT 2
POINT 1 1 1.0
POINT 5 6 2.0

For a three month simulation starting January 1, 2005 where these flows increase each month by 1.0 cms, the input would be:

NUMPT 2
POINT 1 1 1.0
POINT 5 6 2.0
NRPDS 2
INPUT 2005 02 1 0 0 2.0 3.0
INPUT 2005 03 1 0 0 3.0 4.0

Notice that the order of the discharges for the INPUT card follows the order the order specified with the POINT cards.

For a steady-state simulation with two contaminants having concentrations of contaminant 1 at discharge point 1 of 0.1 mg/L and 0.5 mg/L at discharge point 2, and concentrations of contaminant 2 of 10.0 mg/L at discharge point 1 and 50.0 mg/L at discharge point 2, the input would be:

NUMPT 2
POINT 1 1 1.0 0.1 10.0
POINT 5 6 2.0 0.5 50.0

If these contaminant concentrations were to double in February and then again in March during our dynamic simulation, the input would be:

NUMPT 2
POINT 1 1 1.0
POINT 5 6 2.0
NRPDS 2
INPUT 2005 02 1 0 0 2.0 0.2 20.0 3.0 1.0 100.0
INPUT 2005 03 1 0 0 3.0 0.4 40.0 4.0 2.0 200.0

Notice that for the INPUT cards the concentrations for point 1 follow the discharge for point 1 before specifying the discharge at point 2, followed by the concentrations at point two. The order of the constituents is specified in the MAPPING_TABLE file.

GSSHA User's Manual

5 Surface Water Routing
5.1     Channel Routing
5.2     Overland Flow Routing
5.3     Channel Boundary Conditions
5.4     Overland Boundary Conditions
5.5     Embankments
5.6     Overland/Channel Interaction
5.7     Introducing Discharge/Constituent Hydrographs
5.8     Overland Routing with Snow