**Barton Springs Nursery/Ornamental**

NASS data for 2002 (Table 5) indicate that *outside* acreage for
reported ornamental crops in Hays and Travis Counties is negligible
relative to indoor acreage (\< 0.1% total indoor and outdoor acreage).
The majority of acreage for nursery, greenhouse, floriculture,
mushrooms, sod, and vegetable seeds in both years and both counties was
grown under glass or other protection. Three confirmed outdoor nursery
operations reside within the BSS (Kathy Shay, personal communication;
Andrea DeLong-Amaya, personal communication); all three are within the
Travis county portion of the BSS. Total outside wholesale nursery
production in the BSS is approximately three acres.

For the purposes of modeling a nursery/ornamental operation in the BSS,
one of the nurseries\* was used to conceptualize a facility that is
representative of one located within the BSS. Communications with a
staff member were used to parameterize the model. The nursery of
interest has indoor and outdoor areas for growing and maintaining
plants. Outdoor plants include cacti, annuals, perennials, shrubs, and
trees. Outdoor plants are maintained on either weed control mat or on
gravel. Plants are kept in pots of various sizes, ranging from 4" to
multiple gallons, depending upon the type of plant kept within.
Irrigation is carried out daily with either hose or sprinkler systems.
Plants are maintained outside year-round, with some becoming dormant in
the winter and some remaining green. Spring and fall represent the
busiest times for plant production and sales for this nursery (personal
communication with nursery employee).

Based on the above information, several assumptions were made to
parameterize the model. First, it was assumed that the area that would
yield the greatest runoff potential would be from a bare surface that
would be represented by the walkways between the potted plants. These
areas could potentially receive direct applications of pesticides
sprayed on potted plants. Therefore, the surface of the soil was
conceptualized as being gravel or dirt (area under weed mats). This was
an assumption that affected selection of curve numbers, USLE C and
Manning's N. Second, it was assumed that pesticide runoff of potted soil
would not degrade or adsorb and would therefore, be applied directly to
the soil. In order to model this, AMXDR was set to 0. Third, it was
assumed that other crop specific parameters (HTMAX, COVMAX and CINTCP)
were relevant to influencing the application of the pesticide to the
soil.

A soil was selected based on the overlap between the nursery of interest
the soil extents (USDA 2006). Aerial photography was used to identify
the location of the nursery operation and the locations of the outdoor
areas of production. Only one soil type overlapped with the nursery
operation: Tarrant soils and urban land. Therefore, it was determined
that this soil type was a representative soil that an outdoor nursery
operation in the BSS would reside upon. Tarrant is a Hydrologic Group D
soil, with a USLE K factor of 0.32 (USDA 2006). Slopes range from 1 to 8
percent for this series (USDA 1997), but for the portion that overlaps
with the nursery, the slope range is 0 to 2 percent. Since all three
outdoor nursery operations in the BSS are located within Travis County,
soil parameters were obtained soil data mart information pertaining to
Travis County (USDA 2006).

The meteorological station selected for this scenario is located in
Austin, Texas. This station is the closest available weather station
that includes data required for PRZM.

\*The identity and location of the nursery of interest has been
intentionally left out of the metadata for privacy. More information can
be obtained from SRC report submitted with this metadata.

[]{.mark}

+-----------------+----------+-----------------------------------------+
| **Table 1. PRZM |          |                                         |
| 3.12 Climate    |          |                                         |
| and Time        |          |                                         |
| Parameters for  |          |                                         |
| Barton Springs, |          |                                         |
| TX.**           |          |                                         |
+-----------------+----------+-----------------------------------------+
| **Parameter**   | *        | **Source/Comments**                     |
|                 | *Value** |                                         |
+-----------------+----------+-----------------------------------------+
| Starting Date   | Jan. 1,  | Meteorological File from Austin, TX     |
|                 | 1961     | (W13958)                                |
+-----------------+----------+-----------------------------------------+
| Ending Date     | Dec. 31, | Meteorological File from Austin, TX     |
|                 | 1990     | (W13958)                                |
+-----------------+----------+-----------------------------------------+
| Pan Evaporation | 0.69     | PRZM Manual Figure 5.1 (EPA 1998).      |
| Factor (PFAC)   |          |                                         |
+-----------------+----------+-----------------------------------------+
| Snowmelt Factor | 0.36     | PRZM Manual, Table 5.1 (EPA 1998).      |
| (SFAC)          |          |                                         |
+-----------------+----------+-----------------------------------------+
| Minimum Depth   | 25       | Mid point of range (20-30), PRZM        |
| of              |          | Manual, Figure 5.2 (EPA 1998).          |
|                 |          |                                         |
| Evaporation     |          |                                         |
| (ANETD)         |          |                                         |
+-----------------+----------+-----------------------------------------+

+-----------------+----------+-----------------------------------------+
| **Table 2. PRZM |          |                                         |
| 3.12 Erosion    |          |                                         |
| and Landscape   |          |                                         |
| Parameters for  |          |                                         |
| Barton Springs  |          |                                         |
| Nurser          |          |                                         |
| y/Ornamental.** |          |                                         |
+-----------------+----------+-----------------------------------------+
| **Parameter**   | *        | **Source/Comments**                     |
|                 | *Value** |                                         |
+-----------------+----------+-----------------------------------------+
| Method to       | 4 (MUSS) | Default value.                          |
| Calculate       |          |                                         |
| Erosion         |          |                                         |
| (ERFLAG)        |          |                                         |
+-----------------+----------+-----------------------------------------+
| USLE K Factor   | 0.32     | Tarrant soils and urban land, Travis    |
| (USLEK)         | tons     | County (USDA 2006).                     |
|                 | EI^-1^\* |                                         |
+-----------------+----------+-----------------------------------------+
| USLE LS Factor  | 0.20     | Calculated according to Haan and        |
| (USLELS)        |          | Barfield (1978) equation: LS =          |
|                 |          | ((λ/72.6)^m^)((430x^2^ + 30x +          |
|                 |          | 0.43)/6.613), where λ = slope length, x |
|                 |          | = SLP/100 and m = constant. In this     |
|                 |          | case, λ = 400 m (default value) and m = |
|                 |          | 0.3 (EPA 2004).                         |
+-----------------+----------+-----------------------------------------+
| USLE P Factor   | 1        | Assumption that there is no contour     |
| (USLEP)         |          | plowing.                                |
+-----------------+----------+-----------------------------------------+
| Field Area      | 10 ha    | Default value for Pond (EPA, 2004)      |
| (AFIELD)        |          |                                         |
+-----------------+----------+-----------------------------------------+
| NRCS Hyetograph | 4        | PRZM Manual, Figure 5.12 (EPA, 1998).   |
| (IREG)          |          |                                         |
+-----------------+----------+-----------------------------------------+
| Slope (SLP)     | 1 %      | Midpoint value for Tarrant soils and    |
|                 |          | urban land Soil Slope range 0-2% (USDA  |
|                 |          | 2006).                                  |
|                 |          |                                         |
|                 |          | The nursery land is flat, with no       |
|                 |          | slopes (nursery employee)               |
+-----------------+----------+-----------------------------------------+
| Hydraulic       | 356 m    | Default value for Pond (EPA, 2004)      |
| Length (HL)     |          |                                         |
+-----------------+----------+-----------------------------------------+
| Irrigation Flag | 1        | 1 = year round (nursery employee).      |
| (IRFLAG)        |          |                                         |
+-----------------+----------+-----------------------------------------+
| Irrigation Type | 4        | 4 = over canopy sprinkler and flood.    |
| (IRTYP)         |          | Irrigation Guidance for developing PRZM |
|                 |          | Scenario, Table 3; (June 15, 2005).     |
|                 |          |                                         |
|                 |          | Sprinkler and hose irrigation are used  |
|                 |          | daily. Irrigation continues until soil  |
|                 |          | in pots is saturated and water flows    |
|                 |          | out of the pots (nursery employee).     |
+-----------------+----------+-----------------------------------------+
| Leaching Factor | 0.1      | Default value. Irrigation Guidance for  |
| (FLEACH)        |          | developing PRZM Scenario, Table 3;      |
|                 |          | (June 15, 2005).                        |
+-----------------+----------+-----------------------------------------+
| Fraction of     | 1.0      | Set to one to model daily irrigation.   |
| Water Capacity  |          | Irrigation Guidance for developing PRZM |
| when Irrigation |          | Scenario, Table 3; (June 15, 2005).     |
| is Applied      |          |                                         |
| (PCDEPL)        |          |                                         |
+-----------------+----------+-----------------------------------------+
| Maximum Rate at | 0.1      | Default value. Irrigation Guidance for  |
| which           |          | developing PRZM Scenario, Table 3;      |
| Irrigation is   |          | (June 15, 2005).                        |
| Applied         |          |                                         |
| (RATEAP)        |          |                                         |
+-----------------+----------+-----------------------------------------+
| \* EI = 100     |          |                                         |
| ft-tons \* in/  |          |                                         |
| acre\*hr        |          |                                         |
+-----------------+----------+-----------------------------------------+

+-----------------+----------+-----------------------------------------+
| **Table 3. PRZM |          |                                         |
| 3.12 Crop       |          |                                         |
| Parameters for  |          |                                         |
| Barton Springs  |          |                                         |
| Nurser          |          |                                         |
| y/Ornamental.** |          |                                         |
+-----------------+----------+-----------------------------------------+
| **Parameter**   | *        | **Source/Comments**                     |
|                 | *Value** |                                         |
+-----------------+----------+-----------------------------------------+
| Initial Crop    | 1        | Default value                           |
| (INICRP)        |          |                                         |
+-----------------+----------+-----------------------------------------+
| Initial Surface | 1        | 1 = fallow. Assumption: gravel surfaces |
| Condition       |          | kept clear of plant debris.             |
|                 |          |                                         |
| (ISCOND)        |          |                                         |
+-----------------+----------+-----------------------------------------+
| Number of       | 1        | Set to number of crops in simulation.   |
| Different Crops |          | Default value.                          |
| (NDC)           |          |                                         |
+-----------------+----------+-----------------------------------------+
| Number of       | 30       | Set to weather data in meteorological   |
| Cropping        |          | file: Austin, TX (W13958).              |
| Periods (NCPDS) |          |                                         |
+-----------------+----------+-----------------------------------------+
| Maximum         | 0.1      | Table 5-4 PRZM manual, light density    |
| rainfall        |          | crops (EPA, 1998).                      |
| interception    |          |                                         |
| storage of crop |          |                                         |
| (CINTCP)        |          |                                         |
+-----------------+----------+-----------------------------------------+
| Maximum Active  | 0 cm     | Plants are kept in pots so roots are    |
| Root Depth      |          | above the soil.                         |
| (AMXDR)         |          |                                         |
+-----------------+----------+-----------------------------------------+
| Maximum Canopy  | 30 %     | This value was estimated based on       |
| Coverage        |          | assumptions of presence of walkways     |
| (COVMAX)        |          | between plant rows and presence of      |
|                 |          | single plants in pots, which decreases  |
|                 |          | plant density.                          |
+-----------------+----------+-----------------------------------------+
| Soil Surface    | 1        | 1 = fallow. Assumption: gravel surfaces |
| Condition After |          | kept clear of plant debris.             |
| Harvest (ICNAH) |          |                                         |
+-----------------+----------+-----------------------------------------+
| Date of Crop    | 01/01/61 | Set to model continuous maturity.       |
| Emergence       |          |                                         |
|                 |          | During the winter season, some outdoor  |
| (EMD, EMM,      |          | plants senesce and some remain green    |
| IYREM)          |          | (cold hearty perennials) year-round     |
|                 |          | (nursery employee)                      |
+-----------------+----------+-----------------------------------------+
| Date of Crop    | 02/01/61 |                                         |
| Maturity        |          |                                         |
|                 |          |                                         |
| (MAD, MAM,      |          |                                         |
| IYRMAT)         |          |                                         |
+-----------------+----------+-----------------------------------------+
| Date of Crop    | 31/12/61 |                                         |
| Harvest         |          |                                         |
|                 |          |                                         |
| (HAD, HAM,      |          |                                         |
| IYRHAR)         |          |                                         |
+-----------------+----------+-----------------------------------------+
| Maximum Dry     | 0.0      | Not used in scenario.                   |
| Weight (WFMAX)  |          |                                         |
+-----------------+----------+-----------------------------------------+
| Maximum Canopy  | 61 cm    | Heights of plants range from a couple   |
| Height (HTMAX)  |          | of inches (forbes) to ten feet (trees). |
|                 |          | The average height range for plants is  |
|                 |          | 1-2' (nursery employee). 2' was chosen  |
|                 |          | for HTMAX since this value is more      |
|                 |          | representative of the overall plant     |
|                 |          | stock.                                  |
+-----------------+----------+-----------------------------------------+
| SCS Curve       | 89, 89,  | TR-55 (Table 2-2a). CN for open space,  |
| Number (CN)     | 89       | poor condition (grass cover \<50%); as  |
|                 |          | well as impervious dirt areas (USDA     |
|                 |          | 1986).                                  |
+-----------------+----------+-----------------------------------------+
| Manning\'s N    | 0.011    | Value appropriate for gravel. Table 3-1 |
| Value (MNGN)    |          | (USDA 1986).                            |
+-----------------+----------+-----------------------------------------+
| USLE C Factor   | 0        | Assumption that gravel layer will       |
| (USLEC)         |          | impede soil loss.                       |
+-----------------+----------+-----------------------------------------+

+---------+-------------------+---------------------------------------+
| **Table |                   |                                       |
| 4. PRZM |                   |                                       |
| 3.12    |                   |                                       |
| Tarrant |                   |                                       |
| soils   |                   |                                       |
| and     |                   |                                       |
| urban   |                   |                                       |
| land    |                   |                                       |
| Soil    |                   |                                       |
| Par     |                   |                                       |
| ameters |                   |                                       |
| for     |                   |                                       |
| Barton  |                   |                                       |
| S       |                   |                                       |
| prings, |                   |                                       |
| TX      |                   |                                       |
| Nursery |                   |                                       |
| /Orname |                   |                                       |
| ntal.** |                   |                                       |
+---------+-------------------+---------------------------------------+
| **Para  | **Value**         | **Source/Comments**                   |
| meter** |                   |                                       |
+---------+-------------------+---------------------------------------+
| Total   | 20 cm             | Tarrant soils and urban land, 0-2%    |
| Soil    |                   | slopes, Travis County, TX. NRCS Soil  |
| Depth   |                   | Data Mart Database                    |
| (CORED) |                   | (<                                    |
|         |                   | http://soildatamart.nrcs.usda.gov/>). |
|         |                   |                                       |
|         |                   | Additional data were listed for a 3rd |
|         |                   | HORIZN. However, these were not       |
|         |                   | included in this soil profile since   |
|         |                   | the 3rd HORIZN is composed of         |
|         |                   | bedrock.                              |
|         |                   |                                       |
|         |                   | PRZM Scenario Guidance (2004).        |
|         |                   |                                       |
|         |                   | Adjusted using the relationship % OC  |
|         |                   | = % Organic Matter/1.724 (Doucette    |
|         |                   | 2000).                                |
+---------+-------------------+---------------------------------------+
| Number  | 2                 |                                       |
| of      |                   |                                       |
| H       |                   |                                       |
| orizons |                   |                                       |
| (       |                   |                                       |
| NHORIZ) |                   |                                       |
+---------+-------------------+---------------------------------------+
| Horizon | 10 cm (HORIZN =1) |                                       |
| Th      |                   |                                       |
| ickness | 10 cm (HORIZN =2) |                                       |
| (THKNS) |                   |                                       |
+---------+-------------------+---------------------------------------+
| Bulk    | 1.25 g/cm3        |                                       |
| Density | (HORIZN = 1)      |                                       |
| (BD)    |                   |                                       |
|         | 1.25 g/cm3        |                                       |
|         | (HORIZN = 2)      |                                       |
+---------+-------------------+---------------------------------------+
| Initial | 0.229 cm3/cm3     |                                       |
| Water   | (HORIZN =1)       |                                       |
| Content |                   |                                       |
| (THETO) | 0.229 cm3/cm3     |                                       |
|         | (HORIZN =2)       |                                       |
+---------+-------------------+---------------------------------------+
| Comp    | 0.1 cm (HORIZN =  |                                       |
| artment | 1)                |                                       |
| Th      |                   |                                       |
| ickness | 5.0 cm (HORIZN =  |                                       |
| (DPN)   | 2)                |                                       |
+---------+-------------------+---------------------------------------+
| Field   | 0.229cm3/cm3      |                                       |
| C       | (HORIZN =1)       |                                       |
| apacity |                   |                                       |
| (THEFC) | 0.229cm3/cm3      |                                       |
|         | (HORIZN =2)       |                                       |
+---------+-------------------+---------------------------------------+
| Wilting | 0.166 cm3/cm3     |                                       |
| Point   | (HORIZN =1)       |                                       |
| (THEWP) |                   |                                       |
|         | 0.166 cm3/cm3     |                                       |
|         | (HORIZN =2)       |                                       |
+---------+-------------------+---------------------------------------+
| Organic | 2.61 (HORIZN = 1) |                                       |
| Carbon  |                   |                                       |
| Content | 2.61 (HORIZN = 2) |                                       |
| (OC)    |                   |                                       |
+---------+-------------------+---------------------------------------+

  -------------------------------- ---------- --------- ------------ ---------
  **Table 5. NASS 1997/2002 census                                   
  of agriculture for ornamental                                      
  production for open areas versus                                   
  under glass in Hays and Travis                                     
  Counties, Texas (USDA 1997,                                        
  2002).**                                                           

                                   **HAYS**             **TRAVIS**   

  **Crop**                         **1997     **2002    **1997 Total **2002
                                   Total      Total     Acres**      Total
                                   Acres**    Acres**                Acres**

  Nursery, greenhouse,             x          65        x            111
  floriculture, aquatic plants,                                      
  mushrooms, flower seeds,                                           
  vegetable seeds, sod harvested,                                    
  total **In open**                                                  

  Nursery, greenhouse,             x          407,925   x            115,274
  floriculture, aquatic plants,                                      
  mushrooms, flower seeds,                                           
  vegetable seeds, sod harvested,                                    
  total **Under glass (not                                           
  applicable for modeling)**                                         

  Nursery, floriculture, vegetable 26         36        99           106
  and flower seed crops, sod                                         
  harvested, etc., grown in the                                      
  open, irrigated                                                    

  Floriculture crops --            x          14        23           x
  bedding/garden plants, cut                                         
  flowers and cut florist greens,                                    
  foliage plants, and potted                                         
  flowering plants, total , in                                       
  open                                                               

  Bedding/garden plants, in open   4          x         6            4

  Nursery stock, in open           2          27        73           90

  Other nursery and greenhouse     x          25        x            x
  crops, in open                                                     
  -------------------------------- ---------- --------- ------------ ---------

X = data not available, not applicable or withheld

***Sensitive Parameter Uncertainties***

[USLE C Factor and Manning's N Value]{.underline}

The RUSLE Project was not used for determining the USLE C and Manning's
N values. No appropriate scenarios existed in the project for modeling a
gravel surface.

[Soil Data]{.underline}

Only one nursery was used to identify a soil type.

**References:**

EPA. 1998. Carsel, R.F., J.C. Imhoff, P.R. Hummel, J.M. Cheplick, and
A.S. Donigian, Jr. PRZM-3, A Model for Predicting Pesticide and Nitrogen
Fate in the Crop Root and Unsaturated Soil Zones: Users Manual for
Release 3.0. National Exposure Research Laboratory, Office of Research
and Development, U.S. Environmental Protection Agency, Athens, GA.

EPA. 2004. Pesticide Root Zone Model (PRZM) Field and Orchard Crop
Scenarios: Guidance for Selecting Field Crop and Orchard Scenario Input
Parameters. November 15, 2001; Revisions July 2004.

EPA. 2005. Irrigation Guidance for developing PRZM Scenario. June 15,
2005.

Haan, C.T. and B.J. Barfield. 1978. Hydrology and Sedimentology of
Surface Mined Lands. Office of Continuing Education and Extension,
College of Engineering, University of Kentucky, Lexington, Kentucky
40506. pp. 286.

Martinez, R. 2006. NRCS officer for Travis County. Personal
Conversation, March 22, 2006.

Nursery employee. Personal conversation, 23 March 2006.

USDA. 1997. 1997 Census of Agriculture. U.S. Department of Agriculture,
National Agricultural Statistics Service. Accessed March 2006. Online
at: <http://www.nass.usda.gov/index.asp>.

USDA. 2002. 2002 Census of Agriculture. U.S. Department of Agriculture,
National Agricultural Statistics Service. Accessed March 2006. Online
at: <http://www.nass.usda.gov/index.asp>.

USDA. 2006. Soil Survey Areas of Hays Counties, Texas. U.S. Department
of Agriculture, Natural Resources Conservation Service (NRCS), Soil Data
Mart. March 1, 2006. Online at:
[http://soildatamart.nrcs.usda.gov](http://soildatamart.nrcs.usda.gov/).

USDA. 1986. Urban Hydrology for Small Watersheds. United States
Department of Agriculture, Natural Resources Conversation Service.
Technical Release 55.

USDA. 1997. Official Series Description. Tarrant Series. Information
from the website: http://ortho.ftw.nrcs.usda.gov/osd/dat/T/TARRANT.html.