r.agnps50.input(1)	      Grass User's Manual	    r.agnps50.input(1)



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       The  major  objective of the AGNPS-GRASS input interface is to minimize
       the user interaction in preparing the input data for  the  AGNPS  model
       and to minimize the number of user supplied/developed GIS database lay-
       ers. Of the 22 different data required by the model for each cell  (ap-
       pendix  2),  the interface will prepare the input data with only 8 (ap-
       pendix 2) basic GIS database layers supplied by the user and with mini-
       mal  user  interaction.	There are 5 (appendix 2) parameters needed for
       the whole watershed which will be obtained from the user.


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       First start GRASS 5.x from a shelltool window with proper mapset  where
       the data resides


       Execute	_r_._a_g_n_p_s_5_0_._i_n_p_u_t  program from the shelltool window where GRASS
       is running


       A _W_a_t_e_r_s_h_e_d _I_n_p_u_t menu will appear on the shelltool  window  requesting
       the following data/information from the user:


       Watershed  Description:	Enter  a description about the watershed. This
       information optional and will appear in both input and  output  of  the
       AGNPS model run.


       Rainfall  Amount  in  inches:  Enter  the  total  amount of rainfall in
       inches.


       Erosivity Index Value: Enter the erosivity index value for that partic-
       ular storm/rainfall event.


       Enter  the  cell  size  in  meters: The length of the side of a cell in
       meters is entered. The square of the cell size will be the area of each
       cell.


       Enter  a file name to save in AGNPS format: Enter a file name with _._d_a_t
       as the extension to save the AGNPS model  input	file  created  by  the
       AGNPS-GRASS  input  interface  tool. This will be stored in the current
       working directory.


       Enter the watershed name: The name of the watershed should  be  entered
       here.   All  the  input layers should have the same watershed name with
       the proper extension (as _X in appendix 1). Please refer to  appendix  1
       for  the  valid	extensions  and  valid category labels/values that are
       allowed for each layer.


       Then hit the _E_s_c key to continue.




       Error Messages: If any of the category labels/values for the input lay-
       ers  is	not  valid, an error message is printed and the program quits.
       Run _s_u_p_p_o_r_t on the layer where the category label is wrong  to  correct
       it.  The program _s_u_p_p_o_r_t helps to modify the supporting files of a map,
       which include header, category,	color,	and  history.  The  wrong/mis-
       spelled	category  labels  can  be  corrected by running _s_u_p_p_o_r_t on the
       layer to be corrected and choosing the category option. If there is any
       problem	with  the flow direction layer, error messages are printed for
       those cell numbers that had problems and the nature of  those  problems
       (like  circularity, sinks or holes, or flow directions pointing at each
       other).	Use _D_e_d_i_t on the aspect map to correct the problems. The _D_e_d_i_t
       program	helps  to  display  and edit the aspect map with arrows on it,
       which should enable one to correct the flow direction on a cell by cell
       basis.


       For each run of this input interface tool, a new _t_e_m_p___c_e_l_l___n_u_m layer is
       created and stored in the current mapset. In this map,  the  cells  are
       numbered  from  top to bottom and left to right. This is a useful layer
       for editing and interpreting the error messages due to conflicting flow
       direction  for  any  particular	cell. While using the _D_e_d_i_t program to
       correct the errors, this map allows one to locate the cell number where
       conflicts occur.


       Once the input interface completes its run without errors, it saves the
       data in the AGNPS format. The AGNPS model can  be  executed  with  this
       data. The name of the executable file program to run the AGNPS model is
       _a_g_r_u_n.  Type _a_g_r_u_n from the shelltool window where  GRASS  is  running.
       The  program  will  ask	for the input file name. Enter the name of the
       file that was saved by running the AGNPS-GRASS  input  interface,  with
       the  _._d_a_t extension.  The model will output the results of the run with
       a _._n_p_s extension. Both input and output ASCII files are needed to  exe-
       cute the AGNPS-GRASS output interface tool (the Visualization tool).


       AAppppeennddiixx 11



       Watershed boundary

	      (XX.wshd)	Should have category values greater than 0 within  the
	      watershed and 0's outside of the watershed boundary.

       Elevation

	      (XX.elev) Elevation data in meters should be the category	values
	      for  each cell. Also make sure at least 1 row and column of data
	      around the watershed  boundary  exists  to  estimate  slope  and
	      aspect at the boundary of the watershed.

       Aspect

	      (XX.asp.cell_size)  The aspect map should have values between _1_-_8
	      as category values  and should not have any  sinks,  circularity
	      or  more	than one outlet. Cell_size is the number that the user
	      entered for question 4 in the interface input menu.   For  exam-
	      ple, if the watershed is modeled for a 100 meter cell size, then
	      the aspect map name should be XX.asp.100

       Soils

	      (XX.soils) If any of the soil attribute (K factor, clay, sand  or
	      hydrological  soil  group)  maps	do not exist, then the program
	      looks for XX.soils map to extract information  from  the  Soils-5
	      data base. (currently this is not working fully).

       USLE K factor

	      (XX.K)  The  USLE	K factor map should contain the value of the K
	      factor as the category label for each  cell.  This  is  obtained
	      from the soil type map.

       Hydrological soil group

	      (XX.hyg) The category labels allowed are either _A, _B, _C, or _D and
	      should appear as category labels for each cell. This is obtained
	      from the soil type map.

       Sand
	      (XX.sand)	The  percentage of sand content should be the category
	      label for each cell.  This is obtained from the soil type map.

       Clay
	      (XX.clay) The percentage of clay content should  be  there  as  a
	      category	label  for  each  cell. This is obtained from the soil
	      type map.

       Land use

	      (XX.luse) The land use map category labels  allowed  are  _f_a_l_l_o_w,
	      _r_o_w  _c_r_o_p_s,  _s_m_a_l_l _g_r_a_i_n, _l_e_g_u_m_e_s, _r_o_t_a_t_i_o_n _m_e_a_d_o_w, _c_l_o_s_e_-_s_e_e_d_e_d
	      _l_e_g_u_m_e_s, _p_a_s_t_u_r_e, _r_a_n_g_e, _m_e_a_d_o_w, _w_o_o_d_s, _w_o_o_d_l_a_n_d,  _g_r_a_s_s	_w_a_t_e_r_-
	      _w_a_y, _h_a_r_d _s_u_r_f_a_c_e, _f_a_r_m_s_t_e_a_d_s, _r_o_a_d_s _(_d_i_r_t_), _w_a_t_e_r, or _m_a_r_s_h.

       Management Practice

	      (XX.mgpr) The management practice map category labels allowed are
	      _s_t_r_a_i_g_h_t _r_o_w, _c_o_n_t_o_u_r_e_d, or _c_o_n_t_o_u_r_e_d _a_n_d _t_e_r_r_a_c_e_d.

       Nutrient

	      (XX.nut) The cell value should correspond to the level of fertil-
	      izer  application,  i.e  _1,  _2,  _3  or _0. Where 1-low, 2-medium,
	      3-high and 0-urban, water or marsh.  (refer fertilizer level ta-
	      ble).

       Machinery

	      (XX.mach)	This  map  is used to find the fertilizer availability
	      factor for the top 1 cm  depth  of  soil.  The  category	labels
	      allowed  are  _l_a_r_g_e  _o_f_f_s_e_t _d_i_s_k, _m_o_l_d_b_o_a_r_d _p_l_o_w, _l_i_s_t_e_r, _c_h_i_s_e_l
	      _p_l_o_w, _d_i_s_k, _f_i_e_l_d _c_u_l_t_i_v_a_t_o_r, _r_o_w _c_u_l_t_i_v_a_t_o_r, _a_n_h_y_d_r_o_u_s _a_p_p_l_i_c_a_-
	      _t_o_r, _r_o_d _w_e_e_d_e_r, _p_l_a_n_t_e_r, _s_m_o_o_t_h, or _n_o _t_i_l_l. The category label
	      for urban, water, marsh or farmsteads can be no till  or	smooth
	      (refer fertilizer availability factor table).

       Channel slope

	      (XX.chsl)	A  channel  slope length map has to be prepared by the
	      user.  Percentage of channel slope should be the	value  of  the
	      category	in  that  cell. If this layer is missing, the user has
	      the choice to either enter the name of layer which has the chan-
	      nel  slope  values or can accept the default value of 50% of the
	      overland slope value as the channel slope value (recommended  by
	      the AGNPS manual).

       Slope length factor

	      (XX.slen)	A slope length factor layer in feet has to be prepared
	      by the user for each cell. The value should be the value of  the
	      category in that cell.

       USLE C factor

	      (XX.C)  The  USLE	C factor map should contain the value of the C
	      factor as the category label for each cell.


FFeerrttiilliizzaattiioonn lleevveell
       ----------------------------------------------------------
       |Level of      | Assumed fertilization (lb/acre) |	|
       |fertilization | 	 N	   P		| Input |
       |--------------------------------------------------------|
       |None			 0	   0		|  0	|
       |Low			50	   20		|  1	|
       |Medium		       100	   40		|  2	|
       |High		       200	   80		|  3	|
       ----------------------------------------------------------


FFeerrttiilliizzeerr aavvaaiillaabbiilliittyy ffaaccttoorrss aaccccoorrddiinngg
       to tillage practice

       --------------------------------------------------------------
       Tillage practice 	 Fertilizer availability factor (%)
       --------------------------------------------------------------
       Large offset disk		      40
       Moldboard plow			      10
       Lister				      20
       Chisel plow			      67
       Disk				      50
       Field cultivator 		      70
       Row cultivator			      50
       Anhydrous applicator		      85
       Rod weeder			      95
       Planter				      85
       Smooth or no till		     100
       --------------------------------------------------------------

       AAppppeennddiixx 22:: AAGGNNPPSS cceellll iinnppuutt ppaarraammeetteerrss

       box;
       l.
       1. Cell number
       2. Number of cell into which it drains
       3. SCS curve number
       4. Average slope %
       5. Slope shape factor
       6. Average field slope length
       7. Average channel slope
       8. Slope length factor
       9. Mannings roughness coefficient for channel
       10. Soil erodibility factor (K) from USLE
       11. Cropping factor (C) from USLE
       12. Practice factor (P) from USLE
       13. Surface condition constant (based on land use)
       14. Aspect (one of 8 directions indicating drainage from cell)
       15. Soil texture (sand, silt, clay, peat)
       16. Fertilization level (zero, low, medium, high)
       17. Incorporation factor (% fertilizer left in top 1 cm of soil)
       18. Point source indicator (indicates existence of a point source input
       within a cell)
       19. Gully source level (estimate of amount, tons, or gully erosion in a
       cell)
       20. Chemical oxygen demand factor
       21. Impoundment factor (indicating presence of an  impoundment  terrace
       system within the cell)
       22. Channel indicator (indicating existence of a defined channel within
       a cell)


       The 8 basic input GIS layers required for extracting the  data  by  the
       AGNPS-GRASS input interface tool are:

	      Soils

	      Elevation

	      Land use

	      Management practice

	      Fertilizer or nutrient inputs

	      Type of machinery used for land preparation

	      Channel slope

	      Slope length factor

       Five pieces of data are required for the total watershed:

	       Watershed identification/description

	       Precipitation (inches)

	       Erosion Index (EI-value) for that storm/rainfall event

	       Area of each cell (acres)

	       Outlet cell number

       An important implication of this set is that AGNPS does not accommodate
       non-uniform storms, _i_._e_. it uses a lumped  modeling  approach  for  its
       rainfall.


       For  each watershed element, AGNPS requires the following 22 input data
       values (its distributed parameter information):

	       Cell number

	       Number of the cell into which it drains

	       SCS curve number

	       Average land slope (%)

	       Slope shape factor (uniform, convex or concave)

	       Average field slope length (feet)

	       Average channel slope (%)

	       Average channel side slope (%)

	       Mannings roughness coefficient for the channel

	       Soil erodibility factor (K) for USLE

	       Cropping factor (C) for USLE

	       Practice factor (P) for USLE

	       Surface condition constant (factor based on land use)

	       Aspect (one of 8 possible directions indicating	the  principal
	      drainage direction from the cell)

	       Soil texture (sand, silt, clay, peat)

	       Fertilization level (zero, low, medium, high)

	       Incorporation factor (% fertilizer left in top 1 cm of soil)

	       Point  source  indicator (indicates existence of a point source
	      input within a cell)

	       Gully source level (estimate of amount, tons, of gulley erosion
	      in a cell)

	       Chemical oxygen demand factor

	       Impoundment  factor  (indicating the presence of an impoundment
	      terrace system within the cell)

	       Channel indicator (indicating existence of  a  defined  channel
	      within a cell)


SSEEEE AALLSSOO
       _r_._a_g_n_p_s_5_0_._r_u_n

       _r_._a_g_n_p_s_5_0_._v_i_e_w



       AGNPS Page

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GRASS 5.0						    r.agnps50.input(1)
