Template:GUM15

From Gsshawiki
Revision as of 18:53, 20 May 2008 by Eshaw (talk | contribs) (Template:GUM14 moved to Template:GUM15)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search


The following sections provide examples to illustrate the typical form of project files for three situations. The first project file represents the bare minimum input requirements for running GSSHA for a single event with spatially uniform surface roughness and rainfall, without infiltration or channel routing. The second project file shows the required cards for an event simulation with spatially varied rainfall, surface roughness, infiltration and channel routing. The third example shows a project file for GSSHA running in the continuous simulation mode with fully spatially varied inputs.

15.1 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:

Figure 16 – Hydrograph output from simple project example

15.2 Involved Project File

Infiltration can be included in the simulations using one of the optional methods. For the sake of this example, Green & Ampt infiltration will be simulated, which requires additional inputs of porosity, saturated hydraulic conductivity, capillary head parameter, and initial water content as maps or as Mapping Table inputs related to index maps. We will assume that these data are saved in maps named “simple.por”, “simple.sat”, “simple.cap”, and “simple.moi”, respectively. Spatially distributed rainfall will also be input, with two rain gages using inverse distance squared interpolation. The rainfall data are stored in a file called “simple.gag”. A single channel, which consists of two links, will also be simulated. The channel input data file will be called “simple.cip”, with a the channel/grid connectivity file "simple.gst". The format of the channel input files is described in Chapter 5.

The resulting project file for this simulation appears as:

GSSHAPROJECT
WATERSHED_MASK          simple.msk
ELEVATION               simple.ele
QUIET
GRIDSIZE                50.0
ROWS                    10
COLS                    10
TOT_TIME                2000
TIME STEP               20.0
MANNING_N               0.036
PRECIP_FILE		simple.gag
RAIN_INV_DISTANCE
GREEN_AMPT
POROSITY		simple.por
CONDUCTIVITY		simple.sat
CAPILLARY		simple.cap
MOISTURE		simple.moi
CHAN_EXPLIC
CHANNEL_INPUT           simple.cip
STREAM_CELL             simple.gst
SUMMARY                 simple.sum
HYD_FREQ                30
OUTLET_HYDRO            simple.hyd


Notice that the START_DATE and START_TIME project file cards have been removed. These two cards are required only for spatially- and temporally-uniform precipitation, because this information is contained in the precipitation input data file. Also note that the OUTCOL, OUTROW, and OUTSLOPE project file cards have been removed, because they are not required when channel routing is enabled. The outlet of the catchment is determined from the overland flow/channel flow connectivity information provided by the link and node maps.

The four maps simple.por, simple.sat, simple.cap, and simple.moi can also be replaced with tabled values related to an index map, such as a soil texture map. This is the standard way processes are assigned parameter values in WMS 6.1 and higher. In this case the project file would look like.

GSSHAPROJECT
WMS 8.1
WATERSHED_MASK          simple.msk

FLINE                   simple.map
ELEVATION               simple.ele
UNITS                   0
QUIET
GRIDSIZE                50.0
ROWS                    10
COLS                    10
TOT_TIME                2000
TIME STEP               20.0
MANNING_N               0.036
PRECIP_FILE		simple.gag
RAIN_INV_DISTANCE
GREEN_AMPT
MAPPING_TABLE           simple.cmt
DIFFUSIVE_WAVE
CHANNEL_INPUT           simple.cip
STREAM_CELL	        simple.gst
SUMMARY                 simple.sum
HYD_FREQ                30
OUTLET_HYDRO            simple.hyd


And the Mapping Table file named simple.cmt would contain the values of hydraulic conductivity, porosity, suction head, and initial moisture, which would be indexed to integer based index maps, such as a soil-texture map, as described in Section 12. Notice that WMS adds informtion it needs to the project file, including the WMS release verion, and the GIS like map information in the FLINE card. GSSHA ignores these and any other unrecognized project cards, and provides a warning to the screen during execution. Notice that WMS substitues DIFFUSIVE_WAVE for CHAN_EXPLIC, either is acceptable.

15.3 Continuous Simulation Project File

The following example project file will instruct GSSHA to perform a continuous simulation with the Penman-Monteith evapo-transpiration scheme, Green & Ampt infiltration with redistribution (Ogden & Saghafian, 1997), surface retention storage, spatially distributed surface roughness, and rainfall interception. Furthermore, ASCII GRASS maps of spatially distributed depth on the watershed will be written every 30 minutes. WMS is used to develop the inputs, including the MAPPING_TABLE file and index maps of spatially varied watershed properties, such as land use, soil-texture, and combination land-use/soil-texture maps. In this case the project file would look like.

 
GSSHAPROJECT
WATERSHED_MASK		simple.msk
WMS                     8.1
ELEVATION		simple.ele

FLINE                   simple.map
QUIET
GRIDSIZE            	50.0
ROWS                	10
COLS                	10
TIME STEP           	20.0
PRECIP_FILE		simple.gag
RAIN_INV_DISTANCE
LONG_TERM
LATITUDE            	37.15
LONGITUDE		99.34
GMT			-7
ET_CALC_PENMAN
SOIL_MOIST_DEPTH	0.50
TOP_LAYER_DEPTH         0.20
EVENT_MIN_Q		0.01
HMET_WES		simple.hmt
INF_REDIST
MAPPING_TABLE       	simple.cmt
DIFFUSIVE_WAVE
CHANNEL_INPUT	  	simple.cip
STREAM_CELL             simple.gst
SUMMARY             	simple.sum
HYD_FREQ            	30
OUTLET_HYDRO        	simple.hyd
MAP_FREQ		30
MAP_TYPE		0
DEPTH			simple.dep

The Mapping Table file simple.cmt would supply all the needed parameters for overland flow, ET, infiltration, and soil moisture accounting. The mapping table with only the required inputs is shown below. To increase the ability to view the MAPPING_TABLE in the Wiki, the actual table format has been modified. For the correct format please see Section 12.

GSSHA_INDEX_MAP_TABLES
INDEX_MAP                "landuse.idx" "landuse"
INDEX_MAP                "soiltype.idx" "soiltype"
INDEX_MAP                "STLU.idx"     "stlu"
ROUGHNESS "landuse"
NUM_IDS 2
ID    DESCRIPTION1        DESCRIPTION2         SURF_ROUGH
1     developed                                0.05
2     forest                                   0.15
INTERCEPTION "landuse"
NUM_IDS 2
ID    DESCRIPTION1        DESCRIPTION2         STOR_CAPY  INTER_COEF
1     developed                                0.01       0.01
2     forest                                   1.00       0.2
RETENTION "2"
NUM_IDS 2
ID    DESCRIPTION1        DESCRIPTION2         RETENTION_DEPTH
1     developed                                0.1
2     forest                                   2.0
GREEN_AMPT_INFILTRATION "soiltype"
NUM_IDS 2
ID    DESCRIPTION1    HYDR_COND CAPIL_HEAD POROSITY PORE_INDEX RESID_SAT FIELD_CAPACITY
1     clay            0.010000    4.950000    0.437000    0.694000    0.020000    0.30
2     silt            0.300000    2.000000    0.450000    0.400000    0.010000    0.35
GREEN_AMPT_INITIAL_SOIL_MOISTURE "soiltype"
NUM_IDS 2
ID    DESCRIPTION1       DESCRIPTION2         SOIL_MOISTURE
1     clay                                    0.30000
2     silt                                    0.25000                                   
EVAPOTRANSPIRATION "stlu"
NUM_IDS 3
ID    DESCRIPTION1 DESCRIPTION2 ALBEDO  WILTING_PT  VEG_HEIGHT  V_RAD_COEF CANOPY_RESIST
1     silt         forest       0.2     0.2         10.0        0.5       150.0
2     silt         developed    0.4     0.2          0.1        0.1       300.0 
3     clay         forest       0.2     0.1         10.0        0.5       150.0       

As these examples indicate, the complexity of GSSHA simulations is determined by the contents of the project file (and the availability of data, of course). Project files can be built which incorporate every non-exclusive option of GSSHA to perform continuous simulations with complete spatial variability in rainfall, interception, retention storage, evapo-transpiration, overland flow, channel flow, unsaturated zone calculation for infiltration and soil moisture accounting, and lateral saturated groundwater flow with feedback to the unsaturated zone, stream network, and overland flowplane. In the construction of project files, the user must provide all required data for a given option, and avoid specifying mutually exclusive options.