1. General Model Information

Name: Agricultural Non-Point Source pollution model

Acronym: AGNPS

Contact:

Author(s):

Abstract:

AGNPS has three major components:

1. hydrology,
2. soil erosion and
3. nutrient pollution.

The hydrological function provides prediction of runoff volume and peak flow rate. The soil erosion function includes soil erosion and sedimentation. The nutrient function analyzes nitrogen, phosphorous and chemical oxygen demand concentration in the runoff and sediment.

The model requires a total of 22 parameters for execution. These include: Digital Elevation Model (DEM) aspect and slope, soil, land use, and point source information. The model calculates information on the basis of a cell. AGNPS is a single event model for a watershed no larger than several thousand square acres.

Author of the abstract:
CIESIN (CONSORTIUM FOR INTERNATIONAL SCIENCE INFORMATION NETWORK)

II. Technical Information

II.1 Executables:

• http://www.cee.odu.edu/cee/model/agnps.html
• http://www.geog.uni-hannover.de/phygeo/grass/agnps.html
• AGNPS model system (program and user manaual) (2.45 MB)

• http://www.cee.odu.edu/cee/model/agnps_unix.html
• AGNPS model files (program and sample I/O data) for Unix (Solaris 2.5)
  (agnps500.solaris_2.5.tar.gz, 0.10 MB)

II.2 Source-code:

II.3 Manuals:

• AGNPS V 4.03 online manual
• Manual and technical Documents in Word Perfect and MS Word format

  Markus Neteler has compiled a new documentation paket that includes the original documentation of versions 4.03 and 5.00 as well as other technical reports. It is available at

• http://www.geog.uni-hannover.de/phygeo/grass/agnps.html

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

III.2.1 Input

1. cell number (from)
2. receiving cell number (to)
3. SCS curve number
4. land slope
5. land slope shape factor
6. field slope length
7. channel slope
8. channel sideslope
9. Manning's roughness coefficient
10. soil erodibility factor
11. cover and management factor
12. support practice factor
13. surface condition constant
14. aspect (direction of drainage)
15. soil texture
16. fertilization level
17. fertilization availability factor
18. point source indicator
19. gully source level
20. chemical oxygen demand (COD) factor
21. impoundment factor
22. channel indicator

III.2.2 Output

1. watershed description
2. area (acres)
3. area of each cell (acres)
4. characteristic storm precipitation (inches)
5. storm energy-intensity (EI) value

1. runoff volume (inches)
2. peak runoff rate (cfs)
3. fraction of runoff generated within the cell
4. Sediment (by particle size and in total)
5. sediment yield (tons)
6. sediment concentration (ppm)
7. sediment particle size distribution
8. upland erosion (tons/acre)
9. channel erosion (tons/acre)
10. amount of deposition (%)
11. sediment generated within the cell (tons)
12. enrichment ratio
13. delivery ratio

Nutrient

1. Nitrogen
2. sediment associated mass (lbs/acre)
3. concentration of soluble material (ppm)
4. mass of soluble material in runoff (lbs/acre)
5. Phosphorous
6. sediment associated mass (lbs/acre)
7. concentration of soluble material (ppm)
8. mass of soluble material in runoff (lbs/acre)
9. Chemical Oxygen Demand
10. concentration (ppm)
11. mass (lbs/acre)

IV. References