WMS:Land Use Files

When using a land use coverage or grid to map model parameters such as curve number, percent impervious, etc. a corresponding mapping file must be either created manually or imported into WMS. WMS can also export a mapping file created manually so that the same definitions can be remapped in a future model.

Depending on the application, one of three different land use tables will be required:

1. Mapping of land use to CN for hydrologic soil types A, B, C, and D.

2. Mapping of Green & Ampt parameters for the Maricopa County method.

3. Mapping of CASC2D attributes.

Descriptions and examples of each are given below.

Land use tables with corresponding curve numbers for different hydrologic soil groups vary from one text to another, or from one agency to another. For this reason, WMS supports user-defined tables. Users can create tables with the currently required data. The format of the table is shown in Figure 1, and a sample file in Figure 2.

ID1, "Land use description 1", CNA1, CNB1, CNC1, CND1

ID2, "Land use description 2", CNA2, CNB2, CNC2, CND2

ID3, "Land use description 3", CNA3, CNB3, CNC3, CND3

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IDn, "Land use description n", CNAn, CNBn, CNCn, CNDn

Figure 1. Curve Number Land Use File Format.

1, "Fully developed urban areas, Poor Condition", 68, 79, 86, 89

2, "Paved parking lots, roofs, driveways, etc.", 98, 98, 98, 98

3, "Residential 1/8 acre lots (65% impervious)", 77, 85, 90, 92

4, "Residential 1/3 acre lots (30% impervious)", 57, 72, 81, 86

Figure 2. Sample Curve Number Land Use File.

No specific card types are required in this file but a description of each of the six fields required for each land use definition is given below. Each field must be separated by a comma, and the description string must be enclosed by double quotes.

Field	Variable	Value	Description
1	id	+	ID number of land use description.
2	description	str	Land use description.
3-6	curve#	+	SCS Curve Number (CN) for hydrologic soil groups A,B,C,D.

WMS can be used to map Green & Ampt infiltration parameters for HEC-1 using the Maricopa County methods. The file format and an example are given in Figure 3 and Figure 4.

ID1, "Land use description 1", IAB1, RTIMP1, PCTVEG1

ID2, "Land use description 2", IAB2, RTIMP2, PCTVEG2

ID3, "Land use description 3", IAB3, RTIMP3, PCTVEG3

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IDn, "Land use description n", IABn, RTIMPn, PCTVEGn

Figure 3. Green & Ampt Land Use File.

20, "Mountainous shrub and brush", 0.3, 15.0, 50.0

19, "Mountainous forest", 0.25, 30.0, 50.0

29, "Mountainous grassland", 0.15, 55.0, 60.0

7, "Roadway", 0.3, 15.0, 50.0

Figure 4. Sample Green & Ampt Land Use File.

CASC2D map parameters may also be mapped to grid cells using a coverage or grid with an accompanying mapping file. The format of this file is given in Figure 5. The first part of the file serves as a dictionary. You may select any number of the “mappable” attributes listed, but values in the lower part of the table must appear in the same order as they are listed in the dictionary. An example table file is shown in Figure 6.

SOILSTABLE	/* File identifier */
HYDRAULIC_CONDUCTIVITY	/* First field identifier */
CAPILLARY	/* Second field identifier */
POROSITY	/* Third field identifier */
PORE_INDEX	/* Fourth field identifier */
RESIDUAL_SATURATION	/* Fifth field identifier */
MOISTURE_CONTENT	/* Sixth field identifier */
SURFACE_ROUGHNESS	/* Seventh field identifier */
INTERCEPTION_COEFF	/* Eighth field identifier */
STORAGE_CAPACITY	/* Ninth field identifier */
INITIAL_DEPTH	/* Tenth field identifier */
RETENTION	/* Eleventh field identifier */
AREA_REDUCTION	/* Twelfth field identifier */
ALBEDO	/* Thirteenth field identifier */
WILTING_POINT	/* Fourteenth field identifier */
VHEIGHT	/* Fifteenth field identifier */
TCOEFF	/* Sixteenth field identifier */
CANOPY	/* Seventeenth field identifier */
SOIL_ERODABILITY	/* Eighteenth field identifier */
CROP_MANAGEMENT	/* Nineteenth field identifier */
CONSERVATION_PRACTICE	/* Twentieth field identifier */
SAND_MAP	/* Twenty-first field identifier */
SILT_MAP	/* Twenty-second field identifier */
NUMSOILS n	/* Number of soils types in this file */
id1 "description1" hc1 cp1 po1 pi1 rs1 mc1 sr1 ic1 sc1 id1 rt1 ar1 ab1 wp1 vh1 tc1 ca1 se1 cm1 co1 sm1 si1
id2 "description2" hc2 cp2 po2 pi2 rs2 mc2 sr2 ic2 sc2 id2 rt2 ar2 ab2 wp2 vh2 tc2 ca2 se2 cm2 co2 sm2 si2
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idn "descriptionn" hcn cpn pon pin rsn mcn srn icn scn idn rtn arn abn wpn vhn tcn can sen cmn con smn sin

Figure 5. CASC2D Attribute Mapping File Format.

SOILSTABLE

HYDRAULIC_CONDUCTIVITY

CAPILLARY

POROSITY

PORE_INDEX

RESIDUAL_SATURATION

MOISTURE_CONTENT

SURFACE_ROUGHNESS

NUMSOILS 4

1 "Loamy" 0.001000 0.010000 0.100000 0.250000 0.100000 1.000000 0.200000

2 "Sandy" 0.002000 0.010000 0.100000 0.250000 0.100000 1.000000 0.100000

3 "Silty" 0.003000 0.010000 0.100000 0.250000 0.100000 1.000000 0.050000

4 "Clay" 0.004000 0.010000 0.100000 0.250000 0.100000 1.000000 0.030000

Figure 6. Sample CASC2D Attribute Mapping File.