Creating Project Files:Simple Project File

For this project file example, we use an invented watershed data set. The topography of the watershed is shown in the Figure 15 with a 50 m resolution GSSHA grid overlay:

Figure 15 – Example watershed grid with elevation topography

This watershed has a mask map which is appears as (with contrived coordinates):

north:  11000.0
south:  10500.0
east:   2000.0
west:   1500.0
rows:   10
cols:   10
0  0  0  0  1  1  0  0  0  0
0  0  0  1  1  1  0  0  0  0
0  0  1  1  1  1  1  0  0  0
0  1  1  1  1  1  1  1  0  0
1  1  1  1  1  1  1  1  1  0
1  1  1  1  1  1  1  1  1  1
0  1  1  1  1  1  1  1  1  0
0  0  1  1  1  1  1  1  0  0
0  0  0  1  1  1  1  0  0  0
0  0  0  0  1  1  0  0  0  0

In addition, the watershed digital elevation model from which the Figure 15 was derived (using WMS) appears as:

north:  11000.0
south:  10500.0
east:   2000.0
west:   1500.0
rows:   10
cols:   10
  0.0   0.0   0.0   0.0  89.6  85.7   0.0   0.0   0.0   0.0
  0.0   0.0   0.0  86.1  83.1  80.3   0.0   0.0   0.0   0.0
  0.0   0.0  96.7  92.8  80.7  74.8  69.2   0.0   0.0   0.0
  0.0  98.9  90.1  83.5  76.2  71.9  64.8  59.8   0.0   0.0
100.0  92.5  85.5  80.9  66.9  60.3  54.6  50.5  41.5   0.0
101.1  94.6  80.8  77.3  70.2  62.1  50.2  43.2  35.6  30.3
  0.0  97.2  94.8  81.2  77.4  68.6  61.1  52.6  44.9   0.0
  0.0   0.0  95.2  92.2  82.5  73.8  66.1  61.4   0.0   0.0
  0.0   0.0   0.0  94.7  84.9  79.3  71.7   0.0   0.0   0.0
  0.0   0.0   0.0   0.0  87.0  81.3   0.0   0.0   0.0   0.0

The mask and elevation maps were saved in files name “mask.map” and “elev.map”, respectively. Notice that the outlet of the catchment is in row 6 and column 10 of the DEM. This is the lowest point on the perimeter of the watershed. Also notice that the headers for the two maps are identical, and that the grids are square, and 50 m in size.

The following represents the simplest possible project file to run GSSHA. This project file will run GSSHA with a spatially uniform Manning roughness coefficient equal to 0.036 and with spatially uniform rainfall at a rate of 80.0 mm/h for a duration of 2 h (120 min). The simulation will run for 2000 min. The outlet hydrograph will be output every 30 minutes. Notice that lines that begin with the pound sign are comments, which are allowed in the project file.

GSSHAPROJECT
#The only 2 required maps.
WATERSHED_MASK     simple.msk
ELEVATION          simple.ele
#Required watershed geometrical information.
GRIDSIZE           50.0
ROWS               10
COLS               10
#Run duration information.
TOT_TIME           2000
TIME STEP          20.0
#The next 3 lines req’d because no channel routing.
OUTROW             6
OUTCOL             10
OUTSLOPE           0.106
#Spatially-uniform overland flow roughness.
MANNING_N          0.036
#Rainfall input.
PRECIP_UNIF
RAIN_INTENSITY     80.0
RAIN_DURATION      120
#Following two lines required only for spatially-unif. rainfall.
START_DATE         1997	7 17
START_TIME         22 20
#Required output files.
SUMMARY            simple.sum
HYD_FREQ           30
OUTLET_HYDRO       simple.hyd

Without the comments, the project file is more readable:

 
GSSHAPROJECT
WATERSHED_MASK     simple.msk
ELEVATION          simple.ele
GRIDSIZE           50.0
ROWS               10
COLS               10
TOT_TIME           2000
TIME STEP          20.0
OUTROW             6
OUTCOL             10
OUTSLOPE           0.106
MANNING_N          0.036
PRECIP_UNIF
RAIN_INTENSITY     80.0
RAIN_DURATION      120
START_DATE         1997	7 17
START_TIME         22 20
SUMMARY            simple.sum
HYD_FREQ           30
OUTLET_HYDRO       simple.hyd

This project file is saved under the name “simple.prj”. GSSHA is run by typing the command “GSSHA simple.prj”. For this example, the following outflow hydrograph is the result: