Constituents:Point and Non-point sources

Point and Non-point Sources

In addition to the point sources described in the transport section, there is method for specifying time varying point and non-point sources. These point and non-point sources are set up as discrete entries in the point/non-point source file. All of the point and non-point sources are specified as having time varying flows and either 1) a time varying mass input or 2) time varying concentration inputs. To create a constant flow, mass, or concentration, simply put a single time value in the time series. All of these time series will need to be set up in a time series file or files and those files specified in the project file. For more information, see the section of the manual on time series formats.

11.4.1 Project Card

The project card for the point/non-point source file is:

SOURCE_FILE	"filename.src"

11.4.2 File Header

The first line of the file should be a header line identifying the file:

CONSTITUENT_SOURCEFILE

11.4.3 File Organization

The point/non-point source file first sets up specific names for each the point and non-point source spatial distributions. There should be at least one link/node or cell in the distribution file, and there may be more than one (for point sources). For overland point sources, use the SOURCECELLS card and use SOURCENODES for the stream sources. For overland non-point sources, use the SOURCEGRID card.

SOURCECELLS  "source_name"  "distribution_file_name.ext"
SOURCENODES  "source_name"  "distribution_file_name.ext"
SOURCEGRID   "source_name"  "distribution_index_map.ext"

The distribution file is described below.

After the SOURCECELLS and SOURCENODES cards come the point source and non-point source records

11.4.4 Point Sources

Point sources are for inputs that are part of some flow into the domain. These would be outfall points or similar things. The flow specified in the point sources is added to the model as a source into either the overland domain or the stream domain, depending on the type of source chosen (what source type "source_name" is,) and the mass/concentration added to the mass/concentrations of the constituent in the location(s) specified by the "source_name."

POINTSOURCE  "source_name"
FLOW "ts_name"
[constituent_card] [inputs…] 
[constituent_card] [inputs…] 
[constituent_card] [inputs…] 
… 
END_POINTSOURCE

Where the constituent cards and their inputs are from the following

NO2_MASS "mass time series name"
NO2_CONC "concentration time series name"
NO3_MASS "mass time series name"
NO3_CONC "concentration time series name"
NH4_MASS "mass time series name"
NH4_CONC "concentration time series name"
ON_MASS "mass time series name"
ON_CONC "concentration time series name"
OP_MASS "mass time series name"
OP_CONC "concentration time series name"
DP_MASS "mass time series name"
DP_CONC "concentration time series name"
ALG_MASS "mass time series name"
ALG_CONC "concentration time series name"
CBOD_MASS "mass time series name"
CBOD_CONC "concentration time series name"
DO_MASS "mass time series name"
DO_CONC "concentration time series name"
GENERIC_MASS [constituent #] "mass time series name"
GENERIC_CONC [constituent #] "concentration time series name"

Masses are specified in units of kg, while concentrations are specified in units of mg/l.

11.4.5 Non-point Sources

The non-point sources are for loadings that are not dependant upon flow but rather are simply placed across the land surface. Thus, All non-point source loadings are masses, not concentrations. There are two types, instantaneous and continuous. For the continuous loadings, the units are in kg/day/m2. For the instantaneous loadings, the entries in the time series should be just the times of application, and the values should be in units of kg/m2.

Non-point sources due to rainfall are not handled in this file; see the nutrient mapping tables for more information.

NONPOINTSOURCE	“source_name”
[IS_INSTANT]
[constituent card] [inputs…]
[constituent card] [inputs…]
[constituent card] [inputs…]
…
END_NONPOINTSOURCE

Where the constituent cards and their inputs are from the following

NO2_MASS "mass time series name"
NO3_MASS "mass time series name"
NH4_MASS "mass time series name"
ON_MASS "mass time series name"
OP_MASS "mass time series name"
DP_MASS "mass time series name"
ALG_MASS "mass time series name"
CBOD_MASS "mass time series name"
DO_MASS "mass time series name"
GENERIC_MASS [constituent #] "mass time series name"

11.4.6 Point Source Distribution File

The point source distribution file is straightforward. On the first line is the number of cells or nodes, and the following lines either state the cell I and J values or the link and node.

[# point source locations]
[cell I or link] [cell J or node]
[cell I or link] [cell J or node]
[cell I or link] [cell J or node]
…

11.4.7 Channel Point Sources

Point source inputs for channels are described in Section 5.7.

GSSHA User's Manual

11 Constituent Transport and Fate

11.1     Simulating Reactive Constituents in GSSHA

11.2     Transport Formulations

11.3     Simple Constituents

11.4     Point and Non-point sources

11.5     Multi-phase transport