User-defined calibration groups that can be used as conditions in calibration.cal.

There are several SWAT+ files that control the simulation of land use and management. The file landuse.lum summarizes the main land use information and references several other files that specify the details:

• plant.ini stores information about the plants growing in a rotation or plant community,

• management.sch is used to schedule management operations by heat units or dates and/or to list the decision tables to use for scheduling and conditioning management operations,

• lum.dtl contains the land use and management decision tables,

• cntable.lum lists typical Curve Number values for different land use types,

• cons_practice.lum lists the USLE P values and slope lengths for various conservation practices,

• ovn_table.lum lists overland Manning's n values for different tillage and land cover types.

The pointer to the conservation practice database is a foreign key referencing name in cons_practice.lum.

The pointer to the plant community file is a foreign key referencing name in plant.ini.

This number must be consistent with the number of plants listed for the community.

The pointer to the urban database is a foreign key referencing in .

The pointer to the Curve Number database file is a foreign key referencing in .

The pointer to the filter strip file is a foreign key referencing in .

The pointer to the overland Manning's n database is a foreign key referencing in .

The pointer to the management schedule file is a foreign key referencing in .

The name of the land use and management record is a primary key referenced by in . All names in the landuse.lum file must be unique.

The pointer to the user BMP file is a foreign key referencing in .

Most large watersheds and river basins contain areas of urban land use. Estimates of the quantity and quality of runoff in urban areas are required for comprehensive management analysis. SWAT+ calculates runoff from urban areas with the SCS curve number method or the Green & Ampt equation. Loadings of sediment and nutrients are determined using one of two options. The first is a set of linear regression equations developed by the USGS (Driver and Tasker, 1988) for estimating storm runoff volumes and constituent loads. The other option is to simulate the build-up and wash-off mechanisms, similar to SWMM (Storm Water Management Model; Huber and Dickinson, 1988).

References

Driver and Tasker (1988)

Huber and Dickinson (1988)

The pointer to the septic file is a foreign key referencing name in septic.str.

This variable is required for plants that are growing at the beginning of the simulation (lc_status = y).

The pointer to the tile drain file is a foreign key referencing name in tiledrain.str.

The pointer to the grassed waterway file is a foreign key referencing name in grassedww.str.

The name of the plant community is a primary key referenced by plnt_com in landuse.lum. All names in the plant.ini file must be unique.

The plant name is a foreign key referencing the primary key name in plants.plt.

This variable is required for plants that are growing at the beginning of the simulation (lc_status = y).

This variable is required for plants that are growing at the beginning of the simulation (lc_status = y).

The name of the management schedule is a primary key referenced by mgt in landuse.lum. All names in the management.sch file must be unique.

This is the value that is used by the model. The ovn_min and ovn_max values are included in the file to help users stay within reasonable ranges during calibration.

This value is not used by the model. It is included in the file to help users stay within reasonable ranges during calibration.

This value is not used by the model. It is included in the file to help users stay within reasonable ranges during calibration.

A plant community can consist of plants growing at the same time or plants growing in rotation.

The structure of the file plant.ini is different than that of most other SWAT+ input files. The first line for each plant community specifies how many plants there are in the community and what the initial year of the rotation is. It is followed by one line per plant in the community.

Management operations can be scheduled by heat units/dates or by Decision Tables.

The structure of the management.sch file is different than that of most other SWAT+ input files. The first line for each management schedule specifies the name of the schedule and the number of scheduled and/or automatic operations. When using scheduled operations, it is followed by one line per operation listing operation-specific data. The operations must be scheduled by date (Heat Unit scheduling must be done using a Decision Table) listed in chronological order. For automatic operations, the names of the Decision Tables in lum.dtl are listed (one name per line). Behind the name of a Decision Table, the user may list the crop(s) used in the Decision Table, which can be useful when the same Decision Table is used for different crop rotations (see xxx in yyy).

The user may use both scheduled operations and Decision Tables for the same land use. If doing so, the names of the DTs should be listed first.

The name of the Curve Number class is a primary key referenced by cn2 in landuse.lum. All names in the cntable.lum file must be unique.

The name describes the land use type, treatment, and cover condition the Curve Number Values are valid for.

The SCS curve number is a function of the soil’s permeability, land use and antecedent soil water conditions. Typical curve numbers for moisture condition II are listed in the following tables for various land covers and soil types (SCS Engineering Division, 1986). These values are appropriate for a 5% slope.

References

SCS Engineering Division, 1986

The overland flow Manning's n class name is a primary key referenced by ov_mann in landuse.lum. All names in the ovn_table.lum file must be unique.

The name of the conservation practice is a primary key referenced by in . All names in the cons_practice.lum file must be unique.