Section II. D. 6  Page 1 of 120 II. D. Appendices: Drinking Water Exposure 6. N Methyl Carbamate Surface Water Exposure Assessment This appendix provides details on the regional surface water exposure assessments conducted in support of the N methyl carbamate ( NMC) cumulative exposure assessment. A description of the conceptual model and a summary of the analytical plan and results ( focusing on the southeastern region are found in Section I. D). This appendix provides details of the analytical methods, results for each of the regions, and documentation for the modeling inputs and scenarios used for the regional surface water exposures.

A. Constructing the Conceptual Model For surface water exposure, the Agency focused on vulnerable surface water supplies. These vulnerable systems were defined as

small reservoirs in agricultural areas

with high NMC use ( adjusted for relative potency)

and watersheds that are particularly prone to pesticide movement to water ( by runoff and/ or sedimentation)

The Agency used 1997 county level usage data ( Thelin and Gianessi, 2000), with pounds of active ingredient adjusted by the relative potency for the pesticide, to identify high carbamate use areas. Because the usage data represented agricultural usage of the pesticide ( of the NMC pesticides that have the potential to reach drinking water sources, only carbaryl has non agricultural uses), this usage data identified predominantly agricultural areas. Once the regional surface water exposure sites were identified, the Agency used pesticide use surveys from USDA National Agricultural Statistics Service ( NASS) and Doane's to estimate NMC usage in more recent years.

Surface water sources of drinking water were identified using two sources:

A spatial dataset that identifies the population, by county, that gets its drinking water from public surface water supplies ( USGS, 1998);

A spatial dataset showing the location of drinking water intakes for CWS in the U. S. This information was based on the Agency's SDWIS database.

The Agency compared relative vulnerabilities of the areas based on averageannual runoff, average 2 month runoff ( beginning of the growing season), and average soil loss, as developed by the USDA Natural Resources Conservation Service ( Kellogg et al, 1997).

The resulting regional surface water scenario sites are shown in Figure II. D. 6.1. This approach follows the same conceptual model used for the organophosphate ( OP) CRA. Section II. D. 6  Page 2 of 120 II. D. 6. 1  Carbamate cumulative risk assessment regions for drinking water exposure assessment showing high carbamate use areas and regional surface water exposure sites.

For the preliminary NMC CRA, the Agency used estimated carbamate residues from the vulnerable surface water supplies to represent potential NMC exposure from surface water in each region. The Agency assumed that concentrations in the water at the intake represented concentrations found in treated water. This assumption is protective, but not unreasonable, considering the state of published literature on drinking water treatment impacts on NMC pesticides ( Appendix II. D. 3). If carbamate levels in water from these vulnerable sites are not major contributors to the total regional cumulative exposure, then the Agency can reasonably conclude that drinking water exposures will not be a concern in other, less vulnerable, areas. If drinking water exposure from one or more of these vulnerable sites is a significant contributor to the total cumulative exposure, then additional refinements may be necessary to characterize the extent of the potential exposure. Section II. D. 6  Page 3 of 120 B. Estimating Daily Cumulative N methyl Carbamate Concentrations in Surface Water The cumulative assessment focuses on the probability or likelihood of concurrent exposure to multiple pesticides from food, water, and residential use. For surface water sources of drinking water, the Agency determined the potential for co occurrence by considering the potential for more than one NMC pesticide to be used in the same watershed ( on the same or different crops that may be grown in the watershed). The Agency determined the potential for co occurrence at each of the regional surface water exposure sites using USDA National Agricultural Statistics Service ( USDA NASS) and Doane's databases. OPP considered carbamate usage on agricultural crops for a multicounty area surrounding each of the vulnerable surface water exposure sites shown in Figure II. D. 6.1, identifying those carbamate crop uses that accounted for at least 95% of the total carbamate usage in the scenario area. Details of the methods used to collect the usage data can be found in Appendix II. D. 4.

PRZM is a field scale model, while the cumulative water assessment focuses on watershed scale impacts ( i. e., the contributions of multiple carbamate uses on multiple crops occurring in multiple fields in a watershed). The Agency used PRZM to model multiple fields in a watershed, adjusting the estimated exposure concentrations for each carbamate crop use in the watershed by an adjustment factor that reflects the potential area treated ( Figure II. D. 6.2).

This cumulative adjustment factor ( CAF) followed a three step process:

The carbamate crop combination was modeled with PRZM/ EXAMS, using the region specific usage, application timing, soil, site, and weather data. The result is a time series of daily pesticide concentrations in a reservoir spanning a 30 year period.

Each daily concentration is adjusted by the fraction of the watershed that is in the crop being modeled. This is done by dividing the acres of crop grown in the multi county region by the total acres in that region ( percent crop area).

The daily concentrations are then adjusted by the fraction of acres of the crop treated by the particular carbamate. This is done by dividing the acres of crop treated by the total crop acres in the multi county region ( percent crop treated). Section II. D. 6  Page 4 of 120 II. D. 6. 2 Conceptual model for surface water sources of drinking water illustrating how multiple carbamate uses are proportioned in the watershed.

Modeled Watershed Land use in watershed Carbamate use In watershed The adjustments to the estimated daily concentrations for each NMC crop combination are shown in the following equation:

[ C adj]( NMC1, CROPa) = [ C init]( NMC1, CROPa) x RegCA( CROPa) x FractTrt( NMC1, CROPa)

x RPF( NMC1)

where [ C adj]( NMC1, CROPa) is the adjusted concentration for NMC1 on CROPa ( a concentration is estimated for each day over the 30 year period) [ C init]( NMC1, CROPa) is the initial ( unadjusted) concentration for NMC1 on CROPa ( a concentration is estimated for each day over the 30 year period) RegCA( CROPa) is the regional percent crop area, expressed as a fraction = ( Acres of crop planted / ttl acres ag crops) x regional PCA FracTrt( NMC1, CROPa) is the percent of CROPa acres treated with NMC1 RPF( NMC1) is the relative potency factor for NMC1 The resulting adjusted concentrations for each crop carbamate combination are summed across each day to provide a cumulative daily time series, in oxamyl equivalents, over 30 years.

The temporal component of co occurrence of NMC pesticide residues in surface water sources of drinking water is addressed by modeling pesticide applications within Section II. D. 6  Page 5 of 120 the most likely window of application for each crop in each region. Appendix II. D. 4 describes the methods used to estimate the windows of application. The Agency systematically selected the beginning of the most active window for the initial application date of each carbamate. Where multiple applications were identified, the Agency spread those evenly over the most active window.

C. Regional NMC Drinking Water Exposure Estimates From Surface Water Sources The Agency estimated drinking water concentrations for individual carbamate pesticides and for the cumulative carbamate load for each of the regional surface water scenario sites shown in Figure II. D. 6.1. Table II. D. 6.1 gives the cropcarbamate combinations modeled for each region, along with the application related inputs for each combination. More detailed usage information used for the application parameters can be found in Appendix II. D. 4. Chemical specific model inputs are described in Appendix II. D. 5. Documentation of the scenario inputs are provided in Section II. D. 6. D.

Table IID. 6.1. Regional crop carbamate combinations and application related inputs used in the surface water exposure assessment.

Crop/ Use Chemical PRZM scenario App. Rate, kg/ ha App Date No Apps / Interv. ( da) (+) Pct Ac Trt CA M Spray Drift Southeast/ NC ( Regional PCA = 0.61; NMC use PCA = 0.40) Cotton Aldicarb NCcottonC 0.81 ( 0.12*) 1 May 1 0.43 1 0 [ gran] Cotton Carbaryl NCcottonC 0.83 1 Jun 1 0.00 2 0.055 Peanut Aldicarb NCpeanutC 1.20 ( 0.18*) 10 Apr 1 0.62 1 0 [ gran] Peanut Carbaryl NCpeanutC 0.63 30 May 1 0.01 2 0.055 Peanut Oxamyl NCpeanutC 1.39 30 May 1 0.02 2 0.055 Peanut Methomyl NCpeanutC 0.42 30 May 1 0.03 2 0.055 Cucumber Carbaryl NCcucumbCRA 1.11 27 Apr 3 / 14 0.07 2 0.055 Tobacco Aldicarb NCtobaccoC 1.82 ( 0.27*) 30 Apr 1 0.01 1 0 [ gran] Tobacco Carbaryl NCtobaccoC 1.21 30 Apr 3 / 36 0.01 2 0.055 Tobacco Carbofuran NCtobaccoC 4.44 30 Apr 2 / 53 0.00 2 0.055 Tobacco Methomyl NCtobaccoC 0.39 30 Apr 1 0.03 2 0.055 Southeast/ GA ( Regional PCA = 0.61; NMC use PCA = 0.21) Cotton Aldicarb NCCotton / GA met file 0.65 ( 0.10*) 1 May 1 0.22 1 0 [ gran] Peanut Aldicarb NCpeanutC w/ GA met file 1.10 ( 0.16*) 10 Apr 1 0.34 1 0 [ gran] Pecans Aldicarb GAPecanC 3.22 ( 0.48*) 1 May 1 0.01 1 0 [ gran] Section II. D. 6  Page 6 of 120 Table IID. 6.1. Regional crop carbamate combinations and application related inputs used in the surface water exposure assessment.

Crop/ Use Chemical PRZM scenario App. Rate, kg/ ha App Date No Apps / Interv. ( da) (+) Pct Ac Trt CA M Spray Drift Pecans Carbaryl GAPecanC 2.04 1 Aug 2 / 25 0.08 2 0.055 Florida / Central ( Regional PCA = 0.28; NMC use PCA = 0.11) Oranges Aldicarb FLCitrusC 4.27 ( 0.64*) 1 Apr 2 / 121 0.08 1 0 [ gran] Oranges Carbaryl FLcitrusC 3.93 1 Mar 2 / 46 0.01 2 0.055 Oranges Oxamyl FLCitrusC 1.07 1 Apr 3 / 61 0.01 2 0.055 Grapefruit Aldicarb FLCitrusC 4.32 ( 0.65*) 1 Apr 2 / 121 0.07 1 0 [ gran] Grapefruit Carbaryl FLCitrusC 3.47 1 Mar 1 0.03 2 0.055 Florida / South ( Regional PCA = 0.28; NMC use PCA = 0.21) Sugarcane Carbofuran FLsugarcaneC 0.80 20 Jun 1 0.02 2 0.055 Sweet Corn Methomyl FLsweetcornC 0.39 1 Apr 8 0.40 2 0.055 Sweet Corn Carbofuran FLsweetcornC 1.11 1 Aug 1 0.07 2 0.055 Sweet Corn Thiodicarb FLsweetcornC 0.64 1 Apr 4 / 60, 168, 22 0.23 2 0.055 Sweet Corn Methomyl from Thiodi. FLsweetcornC 0.52 3 Apr 4 / 60, 168, 22 0.23 2 0 Pepper Methomyl FLpepperC 0.69 1 Apr 6 / 12 0.16 2 0.055 Pepper Oxamyl FLpepperC 0.57 1 Mar 6 / 20 0.15 2 0.055 Oranges Aldicarb FLCitrusC 4.27 ( 0.64*) 1 Apr 2 / 121 0.14 1 0 [ gran] Oranges Carbaryl FLcitrusC 3.93 1 Mar 2 / 46 0.01 2 0.055 Grapefruit Aldicarb FLCitrusC 4.32 ( 0.65*) 1 Apr 2 / 121 0.09 1 0 [ gran] Grapefruit Carbaryl FLcitrusC 3.47 1 Mar 1 0.07 2 0.055 Cucumber Oxamyl FLcucumberC 0.61 30 Jan 2 / 245 0.50 2 0.055 Cucumber Carbofuran FLcucumberC 1.33 20 Oct 1 0.31 2 0.055 Cucumber Methomyl FLcucumberC 0.64 15 Apr 5 / 12 0.21 2 0.055 Midsouth / LA ( Regional PCA = 0.81; NMC use PCA = 0.50) Cotton Aldicarb MScottonC 0.59 ( 0.09) 1 May 1 0.25 1 0 [ gran] Cotton Carbofuran MScottonC 0.49 24 Jun 1 0.03 2 0.055 Cotton Oxamyl MScottonC 0.21 4 May 1 0.02 2 0.055 Cotton Thiodicarb MScottonC 0.59 1 Jun 2 / 106 0.01 2 0.055 Cotton Methomyl from Thiodi. MScottonC 0.47 3 Jun 2 / 106 0.01 2 0 Corn Carbofuran MScornC 0.94 31 Mar 1 0.02 2 0.055 Sorghum Carbofuran MScornC 0.56 20 Apr 1 0.01 2 0.055 Lower Midwest / TX ( Regional PCA = 0.42; NMC use PCA = 0.20) Section II. D. 6  Page 7 of 120 Table IID. 6.1. Regional crop carbamate combinations and application related inputs used in the surface water exposure assessment.

Crop/ Use Chemical PRZM scenario App. Rate, kg/ ha App Date No Apps / Interv. ( da) (+) Pct Ac Trt CA M Spray Drift Grapefruit Aldicarb STXgrapeftCRA 5.21 ( 0.78*) 2 Jan 1 0.73 1 0 [ gran] Grapefruit Formetanate STXgrapeftCRA 1.02 20 Apr 1 0.35 2 0.0089 Cotton Aldicarb STXcottonCRA 0.54 ( 0.08) 10 Mar 1 0.19 1 0 [ gran] Cotton Oxamyl STXcottonCRA 0.26 15 Mar 2 / 69 0.19 2 0.055 Cotton Carbofuran STXcottonCRA 0.61 28 May 1 0.09 2 0.055 Carrots Oxamyl STXvegetblCRA 1.39 10 Aug 2 / 79 0.91 2 0.0049 Onions Oxamyl STXvegetblCRA 0.53 1 Oct 2 / 31 0.27 2 0.0049 Onions Methomyl STXvegetblCRA 0.54 16 Mar 3 / 213, 76 0.33 2 0.0049 Cucumber Oxamyl STXmelonCRA 0.73 1 Feb 2 / 151 0.31 2 0.0049 Cucumber Methomyl STXmelonCRA 0.52 15 Apr 3 / 20 0.34 2 0.055 Cantaloupe Oxamyl STXmelonCRA 1.95 15 Feb 1 0.23 2 0.0049 Spinach Methomyl STXvegetblCRA 0.50 30 Sep 2 / 83 0.86 2 0.0049 Watermelon Oxamyl STXmelonCRA 0.57 15 Jan 1 0.25 2 0.0049 Peppers Oxamyl STXvegetblCRA 1.11 1 Jan 2 / 182 0.77 2 0.0049 Corn Carbofuran STXcornCRA 0.89 16 Mar 2 / 26 0.08 2 0.0049 North/ northcentral / PA ( Regional PCA = 0.42; NMC use PCA = 0.16) Alfalfa Carbofuran PAalfalfaC 0.67 9 Mar 1 0.03 2 0.055 Apples Methomyl PAappleC 0.44 30 May 3 / 26 0.26 2 0.0087 Apples Oxamyl PAappleC 0.67 20 Apr 1 0.03 2 0.0087 Apples Formetanate PAappleC 0.94 24 Apr 1 0.01 2 0.0087 Apples Carbaryl PAappleC 1.24 20 Apr 2 / 66 0.17 2 0.0087 Corn Carbofuran PAcornC 0.99 10 May 1 0.01 2 0.055 Peaches Methomyl PAappleC 0.47 15 Apr 3 / 48 0.09 2 0.0087 Peaches Carbaryl PAappleC 1.47 15 Jun 3 / 36 0.10 2 0.0087 Potatoes Methomyl PAvegetblCRA 0.50 15 Jun 5 / 21 0.04 2 0.055 Pumpkin Carbofuran PAvegetblCRA 0.90 15 Jun 1 0.25 1 0.0049 Sweet Corn Methomyl PAcornC 0.42 15 Jul 5 / 15 0.34 2 0.055 Sweet Corn Carbofuran PAcornC 1.11 25 Apr 1 0.08 1 0.0049 Sweet Corn Carbaryl PAcornC 1.09 15 Jun 3 / 31 0.07 2 0.055 Sweet Corn Thiodicarb PAcornC 0.64 15 Jul 3 / 38 0.05 2 0.055 Sweet Corn Methomyl from Thiodi. PAcornC 0.51 17 Jul 3 / 38 0.05 2 0 North/ northcentral / IL ( Regional PCA = 0.87; NMC use PCA = 0.45) Alfalfa Carbofuran ILalfalfaCRA 0.79 15 Apr 1 0.01 2 0.055 Beans, Lima Methomyl ILbeanCRA 1.17 15 Jun 1 0.13 2 0.055 Corn Carbaryl ILCornC 1.11 15 May 1 0.00 2 0.055 Corn Carbofuran ILCornC 0.74 20 Jun 1 0.00 2 0.055 Sweet Corn Carbaryl ILCornC 1.66 15 Jul 3 / 21 0.06 2 0.055 Sweet Corn Carbofuran ILCornC 0.39 1 May 1 0.06 2 0.0049 Section II. D. 6  Page 8 of 120 Table IID. 6.1. Regional crop carbamate combinations and application related inputs used in the surface water exposure assessment.

Crop/ Use Chemical PRZM scenario App. Rate, kg/ ha App Date No Apps / Interv. ( da) (+) Pct Ac Trt CA M Spray Drift Northern Great Plains / MN ND ( Regional PCA = 0.83; NMC use PCA = 0.52) Potatoes Aldicarb MNpotatoCRA 2.55 ( 0.38*) 15 May 1 0.02 1 0 [ gran] Potatoes Carbofuran MNpotatoCRA 0.89 13 May 2 / 32 0.01 2 0.0049 Potatoes Oxamyl MNpotatoCRA 0.67 30 May 2 / 46 0.01 2 0.055 Sugar Beets Aldicarb MNsugarbeetC 1.67 ( 0.25*) 30 Apr 1 0.01 1 0 [ gran] Sugar Beets Carbofuran MNsugarbeetC 1.11 1 Jun 1 0.01 2 0.0049 Wheat Carbaryl NDwheatC 0.89 1 Jun 1 0.02 2 0.055 Northwest / WA ( Regional PCA = 0.42; NMC use PCA = 0.23) Apples Carbaryl WAorchardCRA 1.35 15 Apr 2 / 69 0.42 2 0.0087 Apples Formetanate WAorchardCRA 1.08 31 Mar 1 0.05 2 0.0087 Beans, Lima Methomyl WAbeansCRA 1.00 30 May 2 / 61 0.43 2 0.055 Dry Beans/ Peas Aldicarb WAbeansCRA 1.33 ( 0.20*) 1 Apr 1 0.17 1 0 [ gran] Carrots Oxamyl WAbeansCRA 1.09 1 Apr 4 / 19 0.09 2 0.055 Cherries Carbaryl WAorchardCRA 2.03 20 May 2 / 41 0.50 2 0.0087 Onions Oxamyl WAonionsCRA 1.07 15 Mar 2 / 92 0.37 2 0.055 Potatoes Aldicarb WApotatoCRA 3.21 ( 0.48*) 15 May 1 0.36 1 0 [ gran] Potatoes Carbofuran WApotatoCRA 0.74 10 Apr 2 / 36 0.07 2 0.055 Potatoes Oxamyl WApotatoCRA 1.16 10 Apr 3 / 50, 69 0.02 2 0.055 Sweet Corn Methomyl WAswcornCRA 0.49 30 Jun 7 / 13 0.01 2 0.055 Southeast / CA ( Regional PCA = 0.56; NMC use PCA = 0.33) Alfalfa Carbofuran CAalfalfa0C 0.67 18 Feb 1 0.06 2 0.055 Alfalfa Methomyl CAalfalfa0C 0.33 15 Jun 1 0.01 2 0.055 Asparagus Methomyl CAtomato0C 0.91 30 Jun 1 0.36 2 0.055 Broccoli Methomyl CAbroccCVcra 0.63 1 Aug 2 / 45 0.11 2 0.055 Cantaloupe Carbaryl CAtomato0C 0.86 9 Apr 1 0.17 2 0.055 Cantaloupe Methomyl CAtomato0C 0.69 1 Jul 2 / 38 0.36 2 0.055 Cantaloupe Oxamyl CAtomato0C 1.05 19 Apr 1 0.16 2 0.055 Carrots Methomyl CAcarrotCra 0.63 15 Aug 2 / 20 0.04 2 0.055 Cotton Aldicarb CAcotton0C 1.26 ( 0.19*) 15 Apr 1 0.30 1 0 [ gran] Cotton Carbaryl CAcotton0C 0.55 4 Apr 1 0.01 2 0.055 Cotton Carbofuran CAcotton0C 0.54 14 Aug 2 / 19 0.05 2 0.055 Cotton Oxamyl CAcotton0C 0.73 1 Jun 1 0.13 2 0.055 Dry Beans/ Peas Aldicarb CAtomato0C 1.06 ( 0.16*) 20 Apr 1 0.03 1 0 [ gran] Garlic Methomyl CAgarlic0Cra 0.50 29 Apr 3 / 7 0.05 2 0.055 Section II. D. 6  Page 9 of 120 Table IID. 6.1. Regional crop carbamate combinations and application related inputs used in the surface water exposure assessment.

Crop/ Use Chemical PRZM scenario App. Rate, kg/ ha App Date No Apps / Interv. ( da) (+) Pct Ac Trt CA M Spray Drift Garlic Oxamyl CAgarlic0Cra 2.22 24 Mar 1 0.14 2 0.055 Grapefruit Formetanate CAcitrus0C 1.25 26 Apr 2 / 4 0.06 2 0.0087 Grapes Carbofuran CAgrapesC 3.11 1 May 1 0.00 2 0.0087 Grapes, Table Methomyl CAgrapesC 0.83 1 May 1 0.17 2 0.0087 Lemons Formetanate CAcitrus0C 1.17 1 May 2 / 4 0.03 2 0.0087 Lettuce Methomyl CAbroccCVcra 0.77 15 Jun 2 / 84 0.73 2 0.055 Nectarine Carbaryl CAfruit0C 3.55 19 May 1 0.04 2 0.0087 Nectarine Formetanate CAfruit0C 0.78 18 Feb 1 0.46 2 0.0087 Nectarine Methomyl CAfruit0C 0.83 20 Feb 2 / 81 0.12 2 0.0087 Onions Methomyl CAonion0C 0.80 11 May 2 / 35 0.04 2 0.0087 Oranges Carbaryl CAcitrus0C 4.89 17 May 1 0.03 2 0.0087 Oranges Formetanate CAcitrus0C 1.14 22 Apr 1 0.06 2 0.0087 Oranges Methomyl CAcitrus0C 0.67 20 Apr 1 0.01 2 0.0087 Oranges Oxamyl CAcitrus0C 0.56 3 Feb 4 / 13, 101, 80 0.00 2 0.0087 Peaches Carbaryl CAfruit0C 4.46 15 May 2 / 56 0.05 2 0.0087 Peaches Formetanate CAfruit0C 0.88 6 Mar 1 0.05 2 0.0087 Peaches Methomyl CAfruit0C 0.74 10 Apr 1 0.02 2 0.0087 Peaches Oxamyl CAfruit0C 2.22 3 Jan 2 / 21 0.00 2 0.0087 Pistachios Carbaryl 4.44 5 Feb 1 0.03 2 0.0087 Plum/ Prune Carbaryl CAfruit0C 3.30 13 Jan 1 0.03 2 0.0087 Plum/ Prune Formetanate CAfruit0C 1.28 1 Mar 1 0.01 2 0.0087 Potatoes Aldicarb CAtomato0C 3.33 ( 0.50*) 7 May 1 0.10 1 0 [ gran] Potatoes Methomyl CAtomato0C 0.79 7 May 2 / 26 0.09 2 0.055 Sugar Beets Methomyl CAsugarbeet0C 0.58 15 Jun 1 0.54 2 0.055 Tangerine Formetanate CAcitrus0C 0.90 24 Apr 1 0.14 2 0.055 Tomatoes Methomyl CAtomato0C 0.77 15 May 2 / 69 0.40 2 0.055 Tomatoes Oxamyl CAtomato0C 0.66 20 Apr 1 0.01 2 0.055 Watermelon Methomyl CAtomato0C 0.69 10 Jun 2 / 41 0.22 2 0.055 + For multiple applications, intervals are uniform between applications except where varying intervals are indicated. * Because of irregularities in the way PRZM models banded in furrow applications, OPP assumed 15% of applied aldicarb was available in the upper 4 cm of the soil for runoff, reducing the application rate accordingly.

Table II. D. 6.2 summarizes the NMC cumulative residue distributions estimated for each regional exposure site. The regional surface water distributions with the highest peak NMC cumulative loads occurred in the southeastern part of the United States, where high carbamate use, particularly aldicarb, and high rainfall drove the transport of NMC residues into surface water sources of drinking water. The North Carolina site, which represents vulnerable surface water sources in the southeastern coastal plain, had the highest peak cumulative concentrations of any of the regional surface water sites. Aldicarb, which has the highest relative potency of the NMC pesticides, tended to be the major contributor in most of the regional surface water exposures. Section II. D. 6  Page 10 of 120 Table IID. 6.2. Percentile concentrations for estimated N methyl carbamate cumulative distributions in the surface water scenario sites.

Percentile concentration in ug/ L ( oxamyl equivalents) Region/ Site Max 99th 95th 90th 75th 50th Major contributor Southeast / NC 4.2 0.92 0.20 0.079 0.0047 < 0.0001 Aldicarb Southeast / GA 1.2 0.30 0.072 0.019 0.001 < 0.0001 Aldicarb Florida / Central 1.5 0.24 0.040 0.014 0.0021 0.0004 Aldicarb Florida / South 1.0 0.23 0.11 0.061 0.021 0.0067 Carbofuran, methomyl, oxamyl Midsouth / LA 2.3 0.46 0.10 0.041 0.0093 0.0009 Aldicarb Lower Midwest / TX 0.72 0.27 0.11 0.068 0.028 0.0087 Carbofuran, aldicarb, oxamyl Southwest / CA 0.30 0.11 0.045 0.026 0.011 0.0053 Aldicarb, methomyl Northwest / WA 0.18 0.056 0.014 0.0086 0.0048 0.0011 Aldicarb, carbofuran, methomyl, oxamyl North/ N central / IL 0.13 0.046 0.017 0.0095 0.0026 0.0004 Carbofuran North/ N central / PA 0.10 0.032 0.012 0.0066 0.0021 0.0006 Carbofuran Northern Great Plains/ MN ND 0.017 0.0079 0.0032 0.002 0.0006 0.0001 Aldicarb, carbofuran, carbaryl Figure II. D. 6.3 illustrates the year to year variability ( over 30 years of model simulation) in predicted cumulative carbamate concentrations in surface water sources of drinking water in selected regions. For the exposure assessment, pesticide usage ( amount, frequency, timing) was held constant so the variations reflect the range in variability in pesticide concentrations based on weather patterns over time. The peak concentrations in any year tend to be short lived and reflect the intensity and timing of runoff events in relation to the time of application.

II. D. 6. 3  Estimated cumulative carbamate distribution in surface water over 30 years at five regional scenario sites: Southeast/ North Carolina ( pink), Southeast/ Georgia ( yellow), Florida/ south ( light blue), Florida/ central ( purple), Mid south/ Louisiana ( dark blue). Section II. D. 6  Page 11 of 120 Estimated peak concentrations of the individual carbamate pesticides in each of the regional surface water scenario sites were in the sub parts per billion range, except for aldicarb, which had estimated peaks as high as a single part per billion in the northeast NC site ( Table II. D. 6.3).

Table II. D. 6.3. Estimated concentration percentiles, in mg/ L ( ppm), of individual NMC pesticides in each region. Aldicarb Carbaryl Carbofuran Formetanate HCl Methomyl Oxamyl Thiodicarb Southeast / NC Crops cotton, peanut, tobacco cotton, peanut,

cucumber tobacco tobacco peanut, tobacco peanut Maximum 1.48E 03 3.82E 05 2.30E 06 2.50E 05 2.32E 04 99th % ile 3.34E 04 1.57E 05 6.12E 07 3.83E 06 8.47E 06 95th % ile 7.06E 05 6.57E 06 2.36E 07 1.11E 06 1.69E 06 90th % ile 2.56E 05 4.42E 06 1.37E 07 3.82E 07 3.42E 07 80th % ile 4.01E 06 2.36E 06 8.03E 08 9.19E 08 1.14E 08 75th % ile 1.32E 06 1.78E 06 6.37E 08 3.56E 08 1.75E 09 50th % ile 1.31E 08 5.04E 07 8.99E 09 1.88E 10 1.38E 13 Southeast / GA Crops cotton, peanut, pecan pecan Maximum 4.28E 04 5.22E 05 99th % ile 9.82E 05 1.18E 05 Section II. D. 6  Page 12 of 120 Table II. D. 6.3. Estimated concentration percentiles, in mg/ L ( ppm), of individual NMC pesticides in each region. Aldicarb Carbaryl Carbofuran Formetanate HCl Methomyl Oxamyl Thiodicarb 95th % ile 2.20E 05 3.83E 06 90th % ile 5.93E 06 1.89E 06 80th % ile 5.31E 07 2.98E 07 75th % ile 1.41E 07 1.08E 07 50th % ile 9.18E 10 9.75E 09 Florida / South Crops oranges, grapefruit oranges, grapefruit sugarcane sweet corn, cucumber sweet corn, pepper, cucumber pepper, oranges, cucumber sweet corn Maximum 2.37E 05 1.16E 05 8.23E 04 6.27E 04 1.41E 04 5.90E 05 99th % ile 4.57E 06 2.37E 06 1.83E 04 1.75E 04 2.14E 05 6.96E 06 95th % ile 8.23E 07 6.66E 07 8.04E 05 7.79E 05 5.69E 06 2.91E 06 90th % ile 2.35E 07 3.17E 07 4.04E 05 4.16E 05 2.61E 06 1.26E 06 80th % ile 3.69E 08 8.65E 08 1.17E 05 1.57E 05 1.08E 06 2.12E 07 75th % ile 1.69E 08 3.84E 08 7.31E 06 9.86E 06 8.04E 07 7.86E 08 50th % ile 3.73E 10 1.10E 09 9.59E 07 1.66E 06 1.31E 07 7.58E 11 Florida / Central Crops oranges, grapefruit oranges, grapefruit oranges Maximum 5.27E 04 1.14E 04 5.40E 05 99th % ile 8.06E 05 2.62E 05 7.56E 06 95th % ile 1.33E 05 8.70E 06 2.02E 06 90th % ile 4.20E 06 5.18E 06 9.95E 07 80th % ile 7.37E 07 1.71E 06 4.21E 07 75th % ile 3.91E 07 8.76E 07 2.56E 07 50th % ile 3.54E 08 2.03E 08 7.80E 09 Mid South / LA Crops Cotton cotton, corn, sorghum degr of thiodicarb ( cotton) cotton cotton Maximum 8.11E 04 3.32E 04 3.41E 04 1.94E 04 7.53E 05 99th % ile 1.62E 04 1.53E 04 4.80E 05 1.43E 05 2.86E 06 95th % ile 1.71E 05 7.18E 05 8.57E 06 1.39E 06 6.68E 07 90th % ile 3.67E 06 3.91E 05 3.15E 06 3.11E 07 1.14E 07 80th % ile 1.98E 07 1.72E 05 7.72E 07 7.94E 09 5.57E 09 75th % ile 4.70E 08 1.28E 05 4.19E 07 1.00E 09 1.32E 09 50th % ile 3.53E 10 2.29E 06 2.59E 08 3.47E 14 1.38E 12 North Northcentral / PA Crops apple, peach, sweet corn alfalfa, corn, pumpkin, sweet corn apple apple, peach, potato, sweet corn apple sweet corn Maximum 2.36E 05 6.91E 05 7.59E 07 7.03E 05 3.30E 06 2.58E 07 99th % ile 3.33E 06 2.28E 05 8.84E 08 1.57E 05 1.43E 07 1.18E 07 95th % ile 1.06E 06 8.58E 06 1.92E 08 5.66E 06 2.86E 08 4.89E 08 Section II. D. 6  Page 13 of 120 Table II. D. 6.3. Estimated concentration percentiles, in mg/ L ( ppm), of individual NMC pesticides in each region. Aldicarb Carbaryl Carbofuran Formetanate HCl Methomyl Oxamyl Thiodicarb 90th % ile 6.33E 07 4.64E 06 8.60E 09 3.36E 06 6.42E 09 1.80E 08 80th % ile 3.54E 07 1.93E 06 9.49E 10 1.68E 06 2.09E 10 2.45E 09 75th % ile 2.71E 07 1.39E 06 3.35E 10 1.29E 06 3.46E 11 9.78E 10 50th % ile 1.85E 08 1.94E 07 1.92E 11 4.44E 07 4.53E 15 5.85E 12 North NorthCentral / IL Crops corn, sweet corn alfalfa, corn, sweet corn lima beans Maximum 4.44E 05 1.08E 04 1.74E 05 99th % ile 9.68E 06 3.82E 05 2.49E 06 95th % ile 2.52E 06 1.42E 05 5.06E 07 90th % ile 1.45E 06 7.72E 06 1.73E 07 80th % ile 6.16E 07 2.90E 06 8.52E 09 75th % ile 4.49E 07 1.98E 06 2.33E 09 50th % ile 3.87E 08 3.10E 07 1.48E 10 Lower Midwest / TX Crops Grapefruit, cotton Cotton, corn Grapefruit Onions,

cucumber spinach Cotton, carrots, onions,

cucumber cantaloupe watermelon peppers Maximum 8.71E 03 1.06E 02 2.81E 03 1.68E 03 5.27E 03 99th % ile 2.11E 03 5.08E 03 5.74E 04 2.56E 04 1.82E 03 95th % ile 5.82E 04 2.17E 03 7.27E 05 1.02E 04 5.87E 04 90th % ile 2.31E 04 1.29E 03 2.36E 05 5.28E 05 2.82E 04 80th % ile 4.30E 05 6.40E 04 2.42E 06 2.18E 05 1.13E 04 75th % ile 1.62E 05 4.67E 04 6.86E 07 1.47E 05 8.05E 05 50th % ile 3.55E 08 5.94E 05 8.66E 09 2.19E 06 1.55E 05 Southwest / CA Central Valley Crops Cotton, potatoes, beans/ peas Cotton, citrus, grapes, melons, stone fruit Alfalfa, cotton, grapes Citrus, stone fruit Alfalfa, asparagus, carrots, cole crops, garlic, grapes, lettuce, melons, onions, stone fruit, potatoes, sugar beets, tomatoes Cotton, garlic, melon, oranges, peaches, tomatoes Section II. D. 6  Page 14 of 120 Table II. D. 6.3. Estimated concentration percentiles, in mg/ L ( ppm), of individual NMC pesticides in each region. Aldicarb Carbaryl Carbofuran Formetanate HCl Methomyl Oxamyl Thiodicarb Maximum 8.29E 05 1.68E 05 7.88E 05 2.77E 05 4.15E 04 2.41E 05 99th % ile 1.86E 05 5.27E 06 3.62E 05 3.58E 06 8.03E 05 1.18E 05 95th % ile 1.37E 06 2.32E 06 1.77E 05 5.94E 07 3.13E 05 4.70E 06 90th % ile 3.73E 07 1.23E 06 1.05E 05 3.74E 07 1.57E 05 2.21E 06 80th % ile 7.10E 08 5.26E 07 6.06E 06 1.50E 07 7.30E 06 8.04E 07 75th % ile 4.29E 08 3.87E 07 5.13E 06 9.49E 08 5.26E 06 5.28E 07 50th % ile 4.64E 09 7.63E 08 2.75E 06 6.12E 09 1.84E 06 1.23E 07 25th % ile 2.87E 10 3.89E 09 1.07E 06 1.23E 10 5.03E 07 1.95E 08 10th % ile 3.70E 12 1.78E 09 4.35E 07 1.71E 11 1.97E 07 3.36E 09 Minimum 4.86E 15 7.76E 10 6.70E 08 2.63E 12 1.08E 08 1.47E 12 Surface water exposure in each of the regions reflects a distinct seasonal pattern, with greatest exposure coming during the dominant pesticide use season. Figure II. D. 6.4 illustrates this pattern for the Southeast Region ( North Carolina), with the greatest exposures from drinking water occurring in late spring and summer ( May July), dropping to negligible levels during the rest of the year. In contrast, the cumulative ground water exposures showed a less pronounced seasonal trend, with estimated exposures remaining at elevated concentrations for prolonged periods. Similar pattern occur in each of the regions.

Figure II. D. 6,4   Seasonal pattern in estimated concentrations of carbamates in the Southeast / North Carolina exposure site. Section II. D. 6  Page 15 of 120 D. Southeast Region Scenario Documentation 1. North Carolina Cotton ( NCcottonC)

The field used to represent cotton production in North Carolina is located in the Piedmont/ Coastal Plain. According to the 1997 Census of Agriculture, North Carolina is ranked 5th among the major cotton producing states in the U. S. Most cotton is grown in the coastal plain region and approximately 3 percent in the Piedmont. Cotton is planted in the early Spring ( mid April) and harvested beginning in October. Continuous cotton is practice is much of the region and cotton is gradually replacing land once cultivated in tobacco. Row spacing is generally 38 inches with 3 4 plants per foot row. Row canopies tend to be very close to 100 percent, while the canopy between rows is much less. All cotton is defoliated in North Carolina prior to harvesting. Conventional tillage is the dominant practice, but, conservation tillage, no till and strip till practices are gaining in popularity in the region. The crop is rarely grown under irrigation, approximately 5 percent. The soil selected to simulate the field is a Boswell fine sandy loam. Boswell fine sandy loam is a fine, mixed, active, thermic Vertic Paleudalfs. Very little of the soil is in cotton and most remains in woodland or pasture. Boswell fine sandy loam is a deep, moderately well drained, moderate to rapid runoff, very slowly permeable soils formed in marine fluviatile deposits of acid clayey sediments. These soils have a high shrink swell potential. They are located on nearly level to steep uplands of the Southern Coastal Plain. Slopes are generally between 1 to 17 percent. The soils are of large extent in the Southern Coastal Plain region. Boswell fine sandy loam is a Hydrologic Group D soil.

PRZM 3.12 Scenario Input Parameters for Coastal Plain, North Carolina  Cotton Parameter Value Source Starting Date January 1, 1961 Meteorological File  Raleigh, NC ( W13722)

Ending Date December 31, 1990 Meteorological File  Raleigh, NC ( W13722) Pan Evaporation Factor ( PFAC) 0.75 PRZM Manual Figure 5.1 ( EPA, 1998)

Snowmelt Factor ( SFAC) 0.15 cm C 1 PRZM Manual Table 5.1 ( EPA, 1998)

Minimum Depth of Evaporation ( ANETD) 15.0 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.34 tons EI 1* FARM Manual, Table 3.1 ( EPA, 1985)

USLE LS Factor ( USLELS) 1.3 Haan and Barfield, 1978.

USLE P Factor ( USLEP) 1.00 PRZM Manual ( EPA, 1998) Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA, 1999) NRCS Hyetograph ( IREG) 3 PRZM Manual Figure 5.12 ( EPA, 1998) Section II. D. 6  Page 16 of 120 PRZM 3.12 Scenario Input Parameters for Coastal Plain, North Carolina  Cotton Parameter Value Source Slope ( SLP) 6% Selected according to QA/ QC Guidance ( EPA, 2001) Hydraulic Length ( HL) 464 m Shipman Reservoir ( EPA, 1999) Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops ( EPA, 2001) Initial Surface Condition ( ISCOND) 1 Set to default for fallow surface prior to planting Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data. Meteorological File  Raleigh, NC ( W13722) Maximum rainfall interception storage of crop ( CINTCP) 0.2 PRZM Table 5.4 ( EPA, 1998)

Maximum Active Root Depth ( AMXDR) 60 cm PRZM Input Collator; ( Burns, 1992); PRZM Table 5.9 ( EPA, 1998) Maximum Canopy Coverage ( COVMAX) 98 PRZM Input Collator, PIC ( Burns, 1992)

Soil Surface Condition After Harvest ( ICNAH) 3 Residues left on field until following year or cover crop is planted. Date of Crop Emergence ( EMD, EMM, IYREM) 01/ 06 Usual Planting and Harvest Dates for US Field Crops ( USDA, 1984)

Date of Crop Maturity ( MAD, MAM, IYRMAT) 01/ 08 Usual Planting and Harvest Dates for US Field Crops ( USDA, 1984)

Date of Crop Harvest ( HAD, HAM, IYRHAR) 01/ 11 Usual Planting and Harvest Dates for US Field Crops ( USDA, 1984)

Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation SCS Curve Number ( CN) 92, 89, 90 Gleams Manual Table; Fallow SR/ CT/ poor, Cropping and Residue = Row Crop SR/ CT/ poor condition ( USDA, 1990) Manning's N Value ( MNGN) 0.014 RUSLE Project, PB8CTCTC, actually for Columbia, SC cotton, conv till ( USDA, 2000) USLE C Factor ( USLEC) 0.228  0.748 RUSLE Project; PB8CTCTC, actually for Columbia, SC cotton, conv till ( USDA, 2000) Soil Parameters: Boswell series Total Soil Depth ( CORED) 100 cm NRCS, National Soils Characterization Database ( NRCS, 2001) Number of Horizons ( NHORIZ) 3 ( Top horizon split in two) NRCS, National Soils Characterization Database ( NRCS, 2001) Horizon Thickness ( THKNS) 10 cm ( HORIZN = 1) 2 cm ( HORIZN = 2) 88 cm ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001) Section II. D. 6  Page 17 of 120 PRZM 3.12 Scenario Input Parameters for Coastal Plain, North Carolina  Cotton Parameter Value Source Bulk Density ( BD) 1.8 g cm 3 ( HORIZN = 1,2) 1.7 g cm 3 ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

Initial Water Content ( THETO) 0.213 cm3 H2O cm3 soil ( HORIZN = 1, 2) 0.354 cm3 H2O cm3 soil ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 2 cm ( HORIZN = 2,3) Field Capacity ( THEFC) 0.213 cm3 H2O cm3 soil ( HORIZN = 1, 2) 0.354 cm3 H2O cm3 soil ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

Wilting Point ( THEWP) 0.063 cm3 H2O cm3 soil ( HORIZN = 1,2) 0.213 cm3 H2O cm3 soil ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

Organic Carbon Content ( OC) 2.32% ( HORIZN = 1,2) 0.29% ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

2. North Carolina Peanuts ( NCpeanutC)

The field used to represent peanut production in North Carolina is located in Eastern Pitt County in the Coastal Plain. According to the 1997 Census of Agriculture, North Carolina is ranked 3rd among the major peanut producing states in the U. S., accounting for approximately 10 percent of the total U. S. crop. Peanuts are produced mainly on the northeastern coastal plain and a small amount is produced in the southeastern region. The crop is generally planted in the Spring ( mid April to early May) and harvested beginning in September. Crop rotation is the most important cultural practice, with a long rotation ( 3 years) followed by two years of a grass type crop being among the most effective management practices for nematode, diseases, and weed control. Most plantings occurs on raised beds. Row spacing is generally 30 to 48 inches. Conventional tillage is practiced in the region, but strip tillage and no tillage practices are becoming more popular. The crop is rarely grown under irrigation, approximately 10 percent. The soil selected to simulate the field is a Craven silt loam. Craven silt loam is a fine, mixed, subactive, thermic Aquic Hapludults. Approximately one half of the series is used for the production of row crops such as corn, tobacco, cotton, small grain, peanuts and pasture. Craven silt loam is a deep, moderately well drained, medium to rapid runoff, slowly permeable soils formed in clayey Pleistocene sediments. They are located on nearly level to sloping Coastal Plain Uplands. Slopes are generally between 0 to 12 percent. The soils are extensive throughout the Coastal Plain region. Craven silt loam is a Hydrologic Group C soil.

PRZM 3.12 Scenario Input Parameters for Coastal Plain, North Carolina   Tobacco Section II. D. 6  Page 18 of 120 Parameter Value Source Starting Date January 1, 1961 Meteorological File  Raleigh, NC ( W13722) Ending Date December 31, 1990 Meteorological File  Raleigh, NC ( W13722) Pan Evaporation Factor ( PFAC) 0.75 PRZM Manual Figure 5.1 ( EPA, 1998)

Snowmelt Factor ( SFAC) 0.15 cm C 1 PRZM Manual Table 5.1 ( EPA, 1998)

Minimum Depth of Evaporation ( ANETD) 15.0 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.24 tons EI 1* FARM Manual, Table 3.1 ( EPA, 1985)

USLE LS Factor ( USLELS) 1.34 Haan and Barfield, 1978.

USLE P Factor ( USLEP) 1.00 PRZM Manual ( EPA, 1998) Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA, 1999) NRCS Hyetograph ( IREG) 4 PRZM Manual Figure 5.12 ( EPA, 1998)

Slope ( SLP) 6% Selected according to QA/ QC Guidance ( EPA, 2001) Hydraulic Length ( HL) 464 m Shipman Reservoir ( EPA, 1999) Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops ( EPA, 2001) Initial Surface Condition ( ISCOND) 3 American Peanut Council http:// peanutsusa. com/ what/ growing. html Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data. Meteorological File  Raleigh, NC ( W13722) Maximum rainfall interception storage of crop ( CINTCP) 0.1 PRZM Table 5.4 ( EPA, 1998)

Maximum Active Root Depth ( AMXDR) 45 cm PRZM Input Collator; ( Burns, 1992); PRZM Table 5.9 ( EPA, 1998) Maximum Canopy Coverage ( COVMAX) 80 PRZM Input Collator, PIC ( Burns, 1992)

Soil Surface Condition After Harvest ( ICNAH) 3 American Peanut Council http:// peanutsusa. com/ what/ growing. html Date of Crop Emergence ( EMD, EMM, IYREM) 11/ 04 Usual Planting and Harvest Dates for US Field Crops ( USDA, 1984)

Date of Crop Maturity ( MAD, MAM, IYRMAT) 28/ 08 Usual Planting and Harvest Dates for US Field Crops ( USDA, 1984)

Date of Crop Harvest ( HAD, HAM, IYRHAR) 12/ 09 Usual Planting and Harvest Dates for US Field Crops ( USDA, 1984) Section II. D. 6  Page 19 of 120 PRZM 3.12 Scenario Input Parameters for Coastal Plain, North Carolina   Tobacco Parameter Value Source Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation SCS Curve Number ( CN) 89, 84, 86 Gleams Manual Table; close seeded legume, C soil, fallow = fallow SR/ CT poor; cropping and residue = legumes SR poor condition ( USDA, 1990) Manning's N Value ( MNGN) 0.014 RUSLE Project, PB9PRPRC_ runner peanuts, Augusta GA ( nearest peanut) ( USDA, 2000) USLE C Factor ( USLEC) 0.047  0.668 RUSLE Project; PB9PRPRC_ runner peanuts, Augusta GA ( nearest peanut) ( USDA, 2000) Soil Parameters: Craven series Total Soil Depth ( CORED) 100 cm NRCS, National Soils Characterization Database ( NRCS, 2001) Number of Horizons ( NHORIZ) 3 ( Top horizon split in two) NRCS, National Soils Characterization Database ( NRCS, 2001) Horizon Thickness ( THKNS) 10 cm ( HORIZN = 1) 2 cm ( HORIZN = 2) 88 cm ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

Bulk Density ( BD) 1.8 g cm 3 ( HORIZN = 1,2) 1.7 g cm 3 ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

Initial Water Content ( THETO) 0.213 cm3 H2O cm3 soil ( HORIZN = 1, 2) 0.354 cm3 H2O cm3 soil ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 2 cm ( HORIZN = 2,3) Field Capacity ( THEFC) 0.213 cm3 H2O cm3 soil ( HORIZN = 1, 2) 0.354 cm3 H2O cm3 soil ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

Wilting Point ( THEWP) 0.063 cm3 H2O cm3 soil ( HORIZN = 1,2) 0.213 cm3 H2O cm3 soil ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

Organic Carbon Content ( OC) 2.32% ( HORIZN = 1,2) 0.29% ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

3. North Carolina Tobacco ( NCtobaccoC)

The field used to represent tobacco ( flue cured) production in North Carolina is located in Pitt and Johnston Counties, in Eastern North Carolina. According to the 1997 Census of Agriculture, North Carolina is the major producer of tobacco ( 1st overall) in the U. S. Tobacco is grown on a wide variety of soils, however, maximum yields are Section II. D. 6  Page 20 of 120 typically seen on sandy loam soils with low organic matter content. In addition, tobacco roots do not tolerate " wet" soils for prolong periods of time. Approximately 90 percent of the crop is grown in two year rotation. Row spacing is generally from 40 to 48 inches. Tobacco is transplanted from greenhouse or plastic covered outdoor plant beds in early spring after frost pressures ( mid April). Flower heads are removed to induce growth of lateral shoots. Harvesting is done in stages from lowest to highest leaves on the plant as the leaves ripen. Nearly all ( 99 percent) of tobacco is grown with conventional tillage. No till production is used mostly for burley tobacco grown in western North Carolina. The soil selected to simulate the field is a benchmark soil, Norfolk loamy sand. Norfolk loamy sand is a fine loamy, kaolinitic, thermic, Typic Kandiudults. Most of these soils are under cultivation in corn, cotton, peanuts, tobacco and soybeans. Norfolk loamy sand is a very deep, well drained, moderately permeable soil with slow to medium runoff. These soils formed in loamy marine sediments of the Coastal Plain. They are found on level to gently sloping uplands of the Coastal Plain. Slopes range from 0 to 10 percent. The series is of large extent throughout the Coastal Plan. Norfolk loamy sand is a Hydrologic Group B soil.

PRZM 3.12 Scenario Input Parameters for Coastal Plain, North Carolina   Tobacco Parameter Value Source Starting Date January 1, 1961 Meteorological File  Raleigh, NC ( W13722) Ending Date December 31, 1990 Meteorological File  Raleigh, NC ( W13722) Pan Evaporation Factor ( PFAC) 0.75 PRZM Manual Figure 5.1 ( EPA, 1998)

Snowmelt Factor ( SFAC) 0.15 cm C 1 PRZM Manual Table 5.1 ( EPA, 1998)

Minimum Depth of Evaporation ( ANETD) 15.0 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.17 tons EI 1* GLEAMS Table of Representative Soils ( USDA, 1990) USLE LS Factor ( USLELS) 0.192 GLEAMS Table of Representative Soils ( USDA, 1990) USLE P Factor ( USLEP) 0.5 PRZM Table 5.6 value for contour plowing on 5% slope ( EPA, 1998) Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA, 1999) NRCS Hyetograph ( IREG) 3 PRZM Manual Figure 5.12 ( EPA, 1998)

Slope ( SLP) 5% Selected according to QA/ QC Guidance ( EPA, 2001) Hydraulic Length ( HL) 464 m Shipman Reservoir ( EPA, 1999) Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops ( EPA, 2001) Initial Surface Condition ( ISCOND) 1 Set to default for fallow surface prior to planting Section II. D. 6  Page 21 of 120 PRZM 3.12 Scenario Input Parameters for Coastal Plain, North Carolina   Tobacco Parameter Value Source Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data. Meteorological File  Raleigh, NC ( W13722) Maximum rainfall interception storage of crop ( CINTCP) 0.2 PRZM Table 5.4 ( EPA, 1998)

Maximum Active Root Depth ( AMXDR) 60 cm PRZM Table 5.9 ( EPA, 1998)

Maximum Canopy Coverage ( COVMAX) 80 NCSU Crop Profile http:// ipmwww. ncsu. edu/ ncpmip/ Soil Surface Condition After Harvest ( ICNAH) 3 Residues left on field until following year or cover crop is planted. Date of Crop Emergence ( EMD, EMM, IYREM) 11/ 04 PRZM Table 5.9 and NCSU Crop Profile http:// ipmwww. ncsu. edu/ ncpmip/ Date of Crop Maturity ( MAD, MAM, IYRMAT) 07/ 07 PRZM Table 5.9 and NCSU Crop Profile http:// ipmwww. ncsu. edu/ ncpmip/

Date of Crop Harvest ( HAD, HAM, IYRHAR) 16/ 07 PRZM Table 5.9 and NCSU Crop Profile http:// ipmwww. ncsu. edu/ ncpmip/ Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation SCS Curve Number ( CN) 84, 79, 83 Gleams Manual Table A. 3, Fallow SR/ CT/ poor, Cropping and Residue = Row Crop SR/ CT/ poor; B soil ( USDA, 1990) Manning's N Value ( MNGN) 0.014 RUSLE Project, PB6TBHGC; Tobacco, conventional tillage; Greensboro, NC ( USDA, 2000) USLE C Factor ( USLEC) 0.071  0.500 RUSLE Project; PB6TBHGC; Tobacco, conventional tillage; Greensboro, NC ( USDA, 2000) Soil Parameters: Norfolk series Total Soil Depth ( CORED) 150 cm NRCS, National Soils Characterization Database ( NRCS, 2001) Number of Horizons ( NHORIZ) 4 ( Top horizon split in two) NRCS, National Soils Characterization Database ( NRCS, 2001) Horizon Thickness ( THKNS) 10 cm ( HORIZN = 1) 35 cm ( HORIZN = 2) 55 cm ( HORIZN = 3) 50 cm ( HORIZN = 4) NRCS, National Soils Characterization Database ( NRCS, 2001)

Bulk Density ( BD) 1.55 g cm 3 ( HORIZN = 1,2) 1.3 g cm 3 ( HORIZN = 3) 1.1 g cm 3 ( HORIZN = 4) NRCS, National Soils Characterization Database ( NRCS, 2001) Section II. D. 6  Page 22 of 120 PRZM 3.12 Scenario Input Parameters for Coastal Plain, North Carolina   Tobacco Parameter Value Source Initial Water Content ( THETO) 0.199 cm3 H2O cm3 soil ( HORIZN = 1,2) 0.406 cm3 H2O cm3 soil ( HORIZN = 3) 0.396 cm3 H2O cm3 soil ( HORIZN = 4) NRCS, National Soils Characterization Database ( NRCS, 2001)

Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 5.0 cm ( HORIZN = 2,3,4) Field Capacity ( THEFC) 0.199 cm3 H2O cm3 soil ( HORIZN = 1,2) 0.406cm3 H2O cm3 soil ( HORIZN = 3) 0.396 cm3 H2O cm3 soil ( HORIZN = 4) NRCS, National Soils Characterization Database ( NRCS, 2001)

Wilting Point ( THEWP) 0.089 cm3 H2O cm3 soil ( HORIZN = 1,2) 0.206 cm3 H2O cm3 soil ( HORIZN = 3) 0.246 cm3 H2O cm3 soil ( HORIZN = 4) NRCS, National Soils Characterization Database ( NRCS, 2001)

Organic Carbon Content ( OC) 0.29% ( HORIZN = 1,2) 0.116 ( HORIZN = 3) 0.058% ( HORIZN = 4) NRCS, National Soils Characterization Database ( NRCS, 2001)

4. North Carolina Cucumbers ( NCcucumbCRA)

This scenario has been developed for use in the carbamate cumulative drinking water assessment ( 2005). The scenario was adapted from the NC Sweet Potato scenario, which is located in the same area. Soil conditions are the same; crop specific parameters have been adjusted to reflect cucumbers rather than sweet potatoes.

The field used to represent cucumber production in North Carolina is located in the Southern Coastal Plains in Nash County. Nash County has ~ 6,400 acres in cucumber/ pickle production, the highest among NC counties ( USDA Ag Census, 2002). According to the USDA Crop Profile for cucumbers in North Carolina, is ranked 2nd among US states in cucumber production, accounting for ~ 20% of pickling cucumbers ( 27 30,000 acres) and ~ 10% of slicing cucumber production ( 5 8,000 acres) in 1999 ( USDA Crop Profile, Nov 1999; http:// www. ipmcenters. org/ cropprofiles/ docs/ nccucumbers. html ). Most of the cucumber production is in eastern North Carolina. Cucumbers are adapted to a wide range of soils. The crop is grown in two production seasons ( spring and summer), with the average time from seeding to first harvest of 36 to 45 days. Used April 15th planting date to reflect the spring production period. This date is based on BEAD research for the carbamate cumulative assessment ( estimation method and references provided for the carbamate cumulative document). Section II. D. 6  Page 23 of 120 The soil selected to simulate the field is a Craven silt loam. Craven silt loam is a fine, mixed, subactive, thermic Aquic Hapludults. Approximately one half of the series is used for the production of row crops such as corn, tobacco, cotton, small grain, peanuts and pasture. Craven silt loam is a deep, moderately well drained, medium to rapid runoff, slowly permeable soil formed in clayey Pleistocene sediments. They are located on nearly level to sloping Coastal Plain Uplands. Slopes are generally between 0 to 12 percent. The soils are extensive throughout the Coastal Plain region. Craven silt loam is a benchmark soil and a Hydrologic Group C soil.

Scenario Input Parameters for Nash County, North Carolina  Cucumbers Parameter Value Source Starting Date January 1, 1961 Meteorological File  Raleigh, NC ( W13722) Ending Date December 31, 1990 Meteorological File  Raleigh, NC ( W13722) Pan Evaporation Factor ( PFAC) 0.75 PRZM Manual Figure 5.1 ( EPA, 1998)

Snowmelt Factor ( SFAC) 0.15 cm C 1 PRZM Manual Table 5.1 ( EPA, 1998)

Minimum Depth of Evaporation ( ANETD) 15.0 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.42 tons EI 1* FARM Manual, Table 3.1 ( EPA, 1985)

USLE LS Factor ( USLELS) 1.34 Haan and Barfield, 1978.

USLE P Factor ( USLEP) 1.00 PRZM Manual ( EPA, 1998)

Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA, 1999) NRCS Hyetograph ( IREG) 4 PRZM Manual Figure 5.12 ( EPA, 1998)

Slope ( SLP) 6% Mid point of series range for Craven silt loam Hydraulic Length ( HL) 464 m Shipman Reservoir ( EPA, 1999) Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops ( EPA, 2005) Initial Surface Condition ( ISCOND) 1 Pickling cucumbers are generally planted on bare ground; slicing cucumbers are produced on plastic ( USDA Crop Profile, 1999) Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data. Meteorological File  Raleigh, NC ( W13722) Maximum rainfall interception storage of crop ( CINTCP) 0.25 PRZM Table 5.4 ( EPA, 1998) Section II. D. 6  Page 24 of 120 Scenario Input Parameters for Nash County, North Carolina  Cucumbers Parameter Value Source Maximum Active Root Depth ( AMXDR) 50 cm D. C. Sanders, NCSU extension hort specialist. On line publication on vegetable irrigation characterizing cucumber as shallow ( 12 18 in) to moderate ( 18 24 in) rooting depth ( http:// www. ces. ncsu. edu/ depts/ hort/ hil/ hil 33 e. html) Maximum Canopy Coverage ( COVMAX) 80 Estimated based on est for sweet potatoes; consistent w/ range for vegetable crops ( 70 90%) in Table A 1 of scenario input guidance ( EPA, 2005) Soil Surface Condition After Harvest ( ICNAH) 3 residues remain on field until winter cover crop is planted.

Date of Crop Emergence ( EMD, EMM, IYREM) 27/ 04 Based on planting dates of 4/ 15 5/ 15 for slicing cucs, 4/ 20 5/ 20 for pickling cucs ( SE Commercial Vegetable Guide, 2005), estimated emergence 1 week after planting Date of Crop Maturity ( MAD, MAM, IYRMAT) 4/ 06 Assumed 1 week between crop maturity and harvest Date of Crop Harvest ( HAD, HAM, IYRHAR) 11/ 06 Added 45 days from planting to first harvest, based on USDA Crop Profile for NC cucumber ( http:// www. ipmcenters. org/ cropprofiles/ docs / nccucumbers. html ) Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation SCS Curve Number ( CN) 89, 86, 87 Gleams Manual Table A. 3, Fallow SR/ CT/ poor, Cropping and Residue = Row Crop SR/ CT/ poor ( USDA, 1990) Manning's N Value ( MNGN) 0.011 Pb6BGBGC Green Beans, conventional tillage, Cover Code 7 ( clean tilled, smooth or fallow), Greensboro, N. C. These values reordered from RUSLE project so that first value is for the planting date. USLE C Factor ( USLEC) 0.160  0.923 Pb6BGBGC Green Beans, conventional tillage, Cover Code 7 ( clean tilled, smooth or fallow), Greensboro, N. C. Soil Parameters: Craven series Total Soil Depth ( CORED) 100 cm NRCS, National Soils Characterization Database ( NRCS, 2001) Number of Horizons ( NHORIZ) 3 ( Top horizon split in two) NRCS, National Soils Characterization Database ( NRCS, 2001) Horizon Thickness ( THKNS) 10 cm ( HORIZN = 1) 12 cm ( HORIZN = 2) 78 cm ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

Bulk Density ( BD) 1.45 g cm 3 ( HORIZN = 1,2,3) NRCS, National Soils Characterization Database ( NRCS, 2001) Section II. D. 6  Page 25 of 120 Scenario Input Parameters for Nash County, North Carolina  Cucumbers Parameter Value Source Initial Water Content ( THETO) 0.194 cm3 H2O cm3 soil ( HORIZN = 1, 2) 0.321 cm3 H2O cm3 soil ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 2 cm ( HORIZN = 2,3) NRCS, National Soils Characterization Database ( NRCS, 2001) Field Capacity ( THEFC) 0.194 cm3 H2O cm3 soil ( HORIZN = 1, 2) 0.321 cm3 H2O cm3 soil ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

Wilting Point ( THEWP) 0.074 cm3 H2O cm3 soil ( HORIZN = 1,2) 0.201 cm3 H2O cm3 soil ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

Organic Carbon Content ( OC) 1.16% ( HORIZN = 1,2) 0.174% ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001)

5. Georgia Cotton This scenario is a modification of the North Carolina cotton scenario. All of the crop and soil input parameters are the same as that used for the NC scenario. Only the weather station and weather related parameters were changed. For this scenario, OPP used the meteorological file for Augusta, GA ( W3820), which was the closest site within the same MLRA to the GA scenario ( Burke County, GA).

6. Georgia Peanuts This scenario is a modification of the North Carolina peanut scenario. All of the crop and soil input parameters are the same as that used for the NC scenario. Only the weather station and weather related parameters were changed. For this scenario, OPP used the meteorological file for Augusta, GA ( W3820), which was the closest site within the same MLRA to the GA scenario ( Burke County, GA).

7. Georgia Pecans The field used to represent peach production in Georgia is located in Mitchell or Dougherty County in Southwest Georgia ( MLRA133) and the weather station representing the orchard's weather is located in Macon, GA. However, for the carbamate cumulative, OPP used the weather station for Augusta, GA, which was closest to the cumulative exposure site ( in the adjacent county). Pecans are grown throughout the southwestern part of the state. Georgia and Texas generally compete from year to tear for status as the top U. S. producer. As such, production varies significantly from year to year. Trees are very large, growing up to 100 feet tall and living 80 or more years, although production declines as the trees reach the end of its life span. Tree are initially Section II. D. 6  Page 26 of 120 planted at a rate of 27 trees per acre and thinned to 8 trees per acre over an 18 20 year period; approximately 60 feet by 60 feet spacing. Pollinizers are generally planted every 9th or 11th row to facilitate adequate pollination and increases profitability of the stand. Pecan trees require approximately 50 percent foliar canopy for optimal light penetration and crop yield. Proper tree density also allows for better pesticide application. Pecan trees typically produce nuts for 40 or more years. Most ( approximately 65 percent) Georgia pecans are irrigated via drip irrigation systems. Soil characteristics have a significant influences on tree development, fruit bearing capacity, and tree life. Pecan trees prefer light to medium textured soils, pH 5.5 6.0, but can grow on higher clay content and slightly higher pH soils. Soil depth should be several feet or more and water table below the primary root zone. Pecans are native to floodplains and river bottoms having inherently high water requirements. Maturity is reached when the shuck loosens or splits from the shell  harvest then begins. Pecans are harvested with trunk or limb shakers depending on tree age. The soil selected to simulate the field is a Williston loamy fine sand. Williston loamy fine sand is a fine, mixed, superactive, hyperthermic Typic Hapludalfs. Williston loamy fine sand loam is a moderately deep, well drained, moderately rapid runoff, moderately slowly permeable soil that formed in moderately thick beds of clayey marine sediments overlying soft limestone. These soil are generally found on nearly level to sloping landscapes in the Coastal Plain. Slopes is dominantly less than 5 percent but ranges up to 8 percent on hillsides. The soil is of small extent in the Coastal Plains of the South. Williston loamy fine sand is a Hydrologic Group C soil.

PRZM 3.12 Scenario Input Parameters for Mitchell County, Georgia  Pecans Parameter Value Source Starting Date January 1, 1961 Meteorological File   Augusta, GA ( W3820) Ending Date December 31, 1990 Meteorological File   Augusta, GA ( W3820) Pan Evaporation Factor ( PFAC) 0.75 PRZM Manual Figure 5.1 ( EPA, 1998)

Snowmelt Factor ( SFAC) 0.15 cm C 1 PRZM Manual Table 5.1 ( EPA, 1998)

Minimum Depth of Evaporation ANETD) 25.0 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.42 tons EI 1* FARM Manual, Table 3.1 ( EPA, 1985)

USLE LS Factor ( USLELS) 0.35 tons EI 1* Haan and Barfield, 1978.

USLE P Factor ( USLEP) 1.067 PRZM Manual ( EPA, 1998)

Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA, 1999) NRCS Hyetograph ( IREG) 4 PRZM Manual Figure 5.12 ( EPA, 1998)

Slope ( SLP) 5% Mid point of series range for Williston Hydraulic Length ( HL) 464 m Shipman Reservoir ( EPA, 1999) Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops ( EPA, 2005) Section II. D. 6  Page 27 of 120 PRZM 3.12 Scenario Input Parameters for Mitchell County, Georgia  Pecans Parameter Value Source Initial Surface Condition ( ISCOND) 3 Residues remain in field between tree rows, area under trees Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data. Augusta, GA ( W3820)

Maximum rainfall interception storage of crop ( CINTCP) 0.25 PRZM Table 5.4 ( EPA, 1998)

Maximum Active Root Depth ( AMXDR) 100 cm Set to soil horizon depth; main root cluster may grow in excess of 2 meters deep. Tap root will grow to first confining layer. http:// www. uga. edu/ fruit/ pecan. htm Maximum Canopy Coverage ( COVMAX) 50 Based or optimal light penetration and yield. http:// www. uga. edu/ fruit/ pecan. htm Soil Surface Condition After Harvest ( ICNAH) 3 Residues remain in field between tree rows, area under trees. Date of Crop Emergence ( EMD, EMM, IYREM) 21/ 04 Estimated date of canopy leaf out; http:// www. uga. edu/ fruit/ pecan. htm Date of Crop Maturity ( MAD, MAM, IYRMAT) 21/ 09 Estimated date ( based on 180 220 day required growing season) for fruit maturity; http:// www. uga. edu/ fruit/ pecan. htm Date of Crop Harvest ( HAD, HAM, IYRHAR) 01/ 10 Estimated date of harvesting; http:// www. uga. edu/ fruit/ pecan. htm Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation SCS Curve Number ( CN) 84, 79, 82 Gleams Manual Table A. 3, Meadow, conditions good for Hydrologic Soil C; Manning's N Value ( MNGN) 0.07 RUSLE EPA Pesticide Project; Tb7WWSBC; Savannah, GA; Winter Wheat, Cover Code 3 ( residues), Conventional Tillage ( USDA, 2000) USLE C Factor ( USLEC) 0.021  0.259 RUSLE EPA Pesticide Project; Tb7WWSBC; Savannah, GA; Winter Wheat, Cover Code 3 ( residues), Conventional Tillage ( USDA, 2000) Soil Parameters: Craven series Total Soil Depth ( CORED) 100 cm NRCS, National Soils Characterization Database ( NRCS, 2001) Number of Horizons ( NHORIZ) 4 ( Top horizon split in two) NRCS, National Soils Characterization Database ( NRCS, 2001) Horizon Thickness ( THKNS) 10 cm ( HORIZN = 1) 20 cm ( HORIZN = 2) 16 cm ( HORIZN = 3) 54 cm ( HORIZN = 4) NRCS, National Soils Characterization Database ( NRCS, 2001) Section II. D. 6  Page 28 of 120 PRZM 3.12 Scenario Input Parameters for Mitchell County, Georgia  Pecans Parameter Value Source Bulk Density ( BD) 1.45 g cm 3 ( HORIZN = 1,2) 1.7 g cm 3 ( HORIZN = 3,4) NRCS, National Soils Characterization Database ( NRCS, 2001)

Initial Water Content ( THETO) 0.149 cm3 H2O cm3 soil ( HORIZN = 1,2) 0.245 cm3 H2O cm3 soil ( HORIZN = 3) 0.332 cm3 H2O cm3 soil ( HORIZN = 4) NRCS, National Soils Characterization Database ( NRCS, 2001)

Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 5 cm ( HORIZN = 2) 4 cm ( HORIZN = 3) 6 cm ( HORIZN = 4) NRCS, National Soils Characterization Database ( NRCS, 2001)

Field Capacity ( THEFC) 0.149 cm3 H2O cm3 soil ( HORIZN = 1,2) 0.245 cm3 H2O cm3 soil ( HORIZN = 3) 0.332 cm3 H2O cm3 soil ( HORIZN = 4) NRCS, National Soils Characterization Database ( NRCS, 2001)

Wilting Point ( THEWP) 0.069 cm3 H2O cm3 soil ( HORIZN = 1,2) 0.125 cm3 H2O cm3 soil ( HORIZN = 3) 0.192 cm3 H2O cm3 soil ( HORIZN = 4) NRCS, National Soils Characterization Database ( NRCS, 2001)

Organic Carbon Content ( OC) 1.16% ( HORIZN = 1,2) 0.174% ( HORIZN = 3) 0.116% ( HORIZN = 4) NRCS, National Soils Characterization Database ( NRCS, 2001) Section II. D. 6  Page 29 of 120 E. Florida Region Scenario Documentation 1. Florida Citrus The field used to represent citrus production in Florida is located in Collier or Hendry Counties in Southwest Florida, although citrus production areas cover a substantial portion of the state. Citrus production has been moving southward in an attempt to avoid frost damage that has occurred in recent years. According to the 1997 Census of Agriculture, Florida is the major producer of citrus ( oranges) for the juice market and among the highest for the fresh market. Florida is also among the highest producers in other citrus ( grapefruit, tangerines, tangelos, and mandarins). Citrus is generally grown in double rows of trees ( beds) with swales between to move water off site. Areas under and between rows of trees are generally non cultivated/ non maintained except for the occasional mowing. Row spacing ( pairs or rows) is approximately 20 to 25 feet ( paired beds may be less than 20 feet) and between tree spacing is approximately 12 to 15 feet. Row canopies tend to be 100 percent, while the canopy between rows is less to permit the operation of maintenance and harvest equipment. Irrigation is mostly by low volume drip or micro sprinkler systems. The soil selected to simulate the field is a Wabasso fine sand. Wabasso fine sand, is a sandy, siliceous, hyperthermic Alfic Alaquods. These soils are often used for citrus production and truck crops. Wabasso fine sand is a deep to very deep, poorly to very poorly drained, slow to ponded runoff, rapidly permeable in the top horizon and slow to very slowly permeable in the lower horizons soil that formed in sandy and loamy marine sediments. These soils are generally found on flatwoods, flood plains, and depressions and have slopes of 0 to 2 percent. The soil is extensive in Florida. Wabasso fine sand is a Hydrologic Group D soil.

PRZM 3.12 Scenario Input Parameters for Collier & Hendry Counties, Florida  Citrus Parameter Value Source Starting Date January 1, 1961 Meteorological File   West Palm Beach, FL ( W12844) Ending Date December 31, 1990 Meteorological File   West Palm Beach, FL ( W12844) Pan Evaporation Factor ( PFAC) 0.78 PRZM Manual Figure 5.1 ( EPA, 1998)

Snowmelt Factor ( SFAC) 0.0 cm C 1 Does not snow in Southern Florida such that accumulation is expected Minimum Depth of Evaporation ( ANETD) 33.0 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.1 tons EI 1* GLEAMS Manual, table of Representative Soils ( USDA, 1990) USLE LS Factor ( USLELS) 0.093 GLEAMS Manual, table of Representative Soils ( USDA, 1990) USLE P Factor ( USLEP) 1.0 Assume no practice under trees. Section II. D. 6  Page 30 of 120 Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA, 1999) NRCS Hyetograph ( IREG) 4 PRZM Manual Figure 5.12 ( EPA, 1998)

Slope ( SLP) 1% Mid point of soil series range ( EPA, 2001) Hydraulic Length ( HL) 464 m Shipman Reservoir ( EPA, 1999) Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops ( EPA, 2001) Initial Surface Condition ( ISCOND) 1 Set to represent fallow field Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data. West Palm Beach, FL ( W12844) Maximum rainfall interception storage of crop ( CINTCP) 0.25 Maximum recommended value for orchards ( EPA, 2001)

Maximum Active Root Depth ( AMXDR) 100 cm Set to maximum of soil profile. Trees may root from 7 18 feet http:// edis. ifas. ufl. edu Maximum Canopy Coverage ( COVMAX) 60 http:// edis. ifas. ufl. edu Soil Surface Condition After Harvest ( ICNAH) 3 Default, material under trees and between rows is generally left alone Date of Crop Emergence ( EMD, EMM, IYREM) 15/ 02 Date represent early to mid_ season flower bloom for various varieties of citrus http:// edis. ifas. ufl. edu Date of Crop Maturity ( MAD, MAM, IYRMAT) 15/ 10 Date represent late season maturation for various varieties of citrus http:// edis. ifas. ufl. edu Date of Crop Harvest ( HAD, HAM, IYRHAR) 15/ 12 Date represents late season harvest http:// edis. ifas. ufl. edu Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation SCS Curve Number ( CN) 87, 85, 86 Gleams Manual Table A. 3, Meadows, no fallow conditions ( USDA, 1990) Manning's N Value ( MNGN) 0.014 RUSLE Project; UC0CBCBC; Citrus bare ground; conventional tillage; Tampa, FL ( USDA, 2000) USLE C Factor ( USLEC) 0.324  0.488 RUSLE Project; Variable with date, UC0CBCBC; Citrus bare ground; conventional tillage; Tampa, FL ( USDA, 2000) Wabasso Soil Parameters Total Soil Depth ( CORED) 100 cm Number of Horizons ( NHORIZ) 2 ( Base horizons) NRCS, National Soils Characterization Database ( NRCS, 2001)

Horizon Thickness ( THKNS) 10 cm ( HORIZN = 1) 90 cm ( HORIZN = 2) NRCS, National Soils Characterization Database Section II. D. 6  Page 31 of 120 Bulk Density ( BD) 1.45 g cm 3 ( HORIZN = 1) 1.75 g cm 3 ( HORIZN = 2) Initial Water Content ( THETO) 0.066 cm3 H2O cm3 soil ( HORIZN = 1) 0.178 cm3 H2O cm3 soil ( HORIZN = 2) Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 5 cm ( HORIZN = 2) Field Capacity ( THEFC) 0.066 cm3 H2O cm3 soil ( HORIZN = 1) 0.178 cm3 H2O cm3 soil ( HORIZN = 2) Wilting Point ( THEWP) 0.036 cm3 H2O cm3 soil ( HORIZN = 1) 0.078 cm3 H2O

cm3 soil ( HORIZN = 2) Organic Carbon Content ( OC) 2.32% ( HORIZN = 1) 0.29% ( HORIZN = 2) ( NRCS, 2001) http:// www. statlab. iastate. edu/ soils/ ssl/)

2. Florida Cucumber The field used to represent cucumber ( vegetable) production in Florida is located in Collier and Hendry Counties in Southwest Florida, although vegetable production areas include other regions of Florida such as the Everglades Agricultural Area, west central and south eastern regions. According to the 1997 Census of Agriculture, Florida is a major producer of truck crops and is the highest producer of cucumbers. Cucumbers and other truck crops are generally grown on " muck soils," but cucumbers do as well on sandy soils which require less cleaning before marketing. All cucumbers are planted by direct seeding in Florida. Typical planting distances for slicing cucumbers are 48 to 60 inches between rows and 6 to 12 inches between plants. Pickling cucumbers are typically planted at 36 to 48 inches between rows and 2 to 4 inches between plants. When grown using plastic mulch, slicing cucumbers are planted in one or two rows per bed, with 10 to 18 inches between the rows on the bed, 48 to 72 inches between beds, and 8 to 12 inches between holes with one or two plants per hole. Pickling cucumbers are planted at a distance of 3 to 4 inches between plants. At the closest spacing, the plant population is 21,780 per acre. Seeds are planted at a depth of 0.5 to 0.75 inches. Between 35 and 65 days are required from seeding to maturity ( first pick). Cucumbers in Florida are produced using several types of irrigation systems. In mulched production, drip, overhead, and seepage irrigation are used. By raising the water table, seepage irrigation restricts root growth to the bed area. Water is maintained approximately 15 to 18 inches below the soil surface, allowing seepage into the root zone. The soil selected to simulate the field is a Riviera sand. Riviera sand is a loamy, siliceous, active, hyperthermic Arenic Glossaqualfs. These soils are often used for truck crop and citrus production. Riviera sand is a deep, poorly drained, slow runoff, slowly to very slowly permeable soil that formed in stratified marine sandy and loamy sediments on the Lower Coastal Plain. These soil are generally found on broad, low flats and in Section II. D. 6  Page 32 of 120 depressions and have slopes generally less than 2 percent. The soil is of moderate extent. Riviera sand is a Hydrologic Group C soil.

PRZM 3.12 Scenario Input Parameters for Collier & Hendry Counties, Florida  Cucumber Parameter Value Source Starting Date January 1, 1961 Meteorological File  West Palm Beach, FL ( W12844) Ending Date December 31, 1990 Meteorological File  West Palm Beach, FL ( W12844) Pan Evaporation Factor ( PFAC) 0.78 PRZM Manual Figure 5.1 ( EPA, 1998)

Snowmelt Factor ( SFAC) 0.0 cm C 1 No appreciable snow accumulation occurs in this part of Florida Minimum Depth of Evaporation ( ANETD) 33.0 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.03 tons EI 1* PRZM Input Collator ( Burns, 1992) and FARM Manual ( EPA, 1985) USLE LS Factor ( USLELS) 0.2 Haan and Barfield, 1979 USLE P Factor ( USLEP) 1.0 PRZM Manual ( EPA, 1998)

Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA, 1999) NRCS Hyetograph ( IREG) 4 PRZM Manual Figure 5.12 ( EPA, 1998)

Slope ( SLP) 1% Mid point of soil series range ( EPA, 2001) Hydraulic Length ( HL) 464 m Shipman Reservoir ( EPA, 1999) Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops ( EPA, 2001) Initial Surface Condition ( ISCOND) 1 Field are fallow prior to planting Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data. Meteorological File  West Palm Beach, FL ( W12844) Maximum rainfall Interception storage of crop ( CINTCP) 0.15 PIC; confirmed using Table 5.4 from PRZM Manual ( Burns, 1992 and EPA, 1985)

Maximum Active Root Depth ( AMXDR) 50 cm Florida Cucumber Crop Profile, USDA Maximum Canopy Coverage ( COVMAX) 80 PIC ( Burns, 1992)

Soil Surface Condition After Harvest ( ICNAH) 3 Plant residues are left behind until later in the year when tilled for next series of crops; rarely cucumbers. Section II. D. 6  Page 33 of 120 Date of Crop Emergence ( EMD, EMM, IYREM) 10/ 10 Florida Cucumber Crop Profile, USDA http:// pestdata. ncsu. edu/ cropprofiles/ cropprofiles. cfm Date of Crop Maturity ( MAD, MAM, IYRMAT) 05/ 12 Florida Cucumber Crop Profile, USDA http:// pestdata. ncsu. edu/ cropprofiles/ cropprofiles. cfm Date of Crop Harvest ( HAD, HAM, IYRHAR) 10/ 12 Florida Cucumber Crop Profile, USDA http:// pestdata. ncsu. edu/ cropprofiles/ cropprofiles. cfm Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation SCS Curve Number ( CN) 91, 87, 88 Gleams Manual Table A. 3, Fallow = SR poor, Cropping and Residue = Row Crop SR/ poor ( USDA, 1990) Manning's N Value ( MNGN) 0.011 RUSLE Project; UC0BGBGC; Green Beans, conventional tillage; Tampa, FL ( USDA, 2000) USLE C Factor ( USLEC) 0.162  0.938 RUSLE Project; UC0BGBGC; Green Beans, conventional tillage; Tampa, FL, Variable with date ( USDA, 2000) Riviera Soil Parameters Total Soil Depth ( CORED) 100 cm Number of Horizons ( NHORIZ) 3 ( top horizon split in two) NRCS, National Soils Characterization Database ( NRCS, 2001)

Horizon Thickness ( THKNS) 10 cm ( HORIZN = 1) 62 cm ( HORIZN = 2) 28 cm ( HORIZN = 3) Bulk Density ( BD) 1.65 g cm 3 ( HORIZN = 1,2) 1.7 g cm 3 ( HORIZN = 3) Initial Water Content ( THETO) 0.073 cm3 H2O cm3 soil ( HORIZN = 1,2) 0.211 cm3 H2O cm3 soil ( HORIZN = 3) Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 2 cm ( HORIZN = 2,3) Field Capacity ( THEFC) 0.073 cm3 H2O cm3 soil ( HORIZN = 1,2) 0.211 cm3 H2O cm3 soil ( HORIZN = 3) Wilting Point ( THEWP) 0.023 cm3 H2O cm3 soil ( HORIZN = 1,2) 0.091 cm3 H2O cm3 soil ( HORIZN = 3) Organic Carbon Content ( OC) 1.16% ( HORIZN = 1,2) 0.174% ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001) http:// www. statlab. iastate. edu/ soils/ ssl/)

Ed Russell ( USDA_ NRCS, Fresno)

3. Florida Peppers  Bell Section II. D. 6  Page 34 of 120 The field used to represent pepper ( bell peppers) production in Florida is located in Collier and Hendry Counties in Southwest Florida, although vegetable production areas include other regions of Florida such as the Everglades Agricultural Area, westcentral and south eastern regions. According to the 1997 Census of Agriculture, Florida is a major producer of truck crops and is the highest producer of bell peppers. Peppers and other truck crops are generally grown on " muck soils," but peppers do as well on sandy soils which require less cleaning before marketing. Peppers ( bell peppers) are planted mainly by transplant, but some direct seeding in does occur in Florida. Typical planting distances for most peppers are 36 to 42 inches between rows and 12 to 16 inches between plants in a row. When grown using plastic mulch, which is a common practice in Florida, planting distances change very little. Peppers are generally harvested two or more times during the course of the growing season and in Southern Florida, where frost pressures are minimal, they are planted and harvested throughout the year. Peppers in Florida are produced using several types of irrigation systems. In mulched production, drip irrigation is highly recommended because of less water use, lower weed production, and some evidence of increased yields. Various forms of sprinkler irrigation may also be used. The soil selected to simulate the field is a Riviera sand. Riviera sand is a loamy, siliceous, active, hyperthermic Arenic Glossaqualfs. These soils are often used for truck crop and citrus production. Riviera sand is a deep, poorly drained, slow runoff, slowly to very slowly permeable soil that formed in stratified marine sandy and loamy sediments on the Lower Coastal Plain. These soil are generally found on broad, low flats and in depressions and have slopes generally less than 2 percent. The soil is of moderate extent. Riviera sand is a Hydrologic Group C soil.

PRZM 3.12 Scenario Input Parameters for Collier and Hendry Counties, Florida  Bell Peppers Parameter Value Source Starting Date January 1, 1961 Meteorological File  West Palm Beach, FL ( W12844) Ending Date December 31, 1990 Meteorological File  West Palm Beach, FlL( W12844) Pan Evaporation Factor ( PFAC) 0.78 PRZM Manual Figure 5.1 ( EPA, 1998)

Snowmelt Factor ( SFAC) 0.0 cm C 1 No appreciable snow accumulation occurs in this part of Florida Minimum Depth of Evaporation ( ANETD) 33.0 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.03 tons EI 1* PRZM Input Collator ( Burns, 1992) and FARM Manual ( EPA, 1985) USLE LS Factor ( USLELS) 0.2 Haan and Barfield, 1979 USLE P Factor ( USLEP) 1.0 PRZM Manual ( EPA, 1998)

Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA, 1999) NRCS Hyetograph ( IREG) 4 PRZM Manual Figure 5.12 ( EPA, 1998) Section II. D. 6  Page 35 of 120 Slope ( SLP) 1% Mid point of soil series range ( EPA, 2001) Hydraulic Length ( HL) 464 m Shipman Reservoir ( EPA, 1999) Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops ( EPA, 2001) Initial Surface Condition ( ISCOND) 1 Field are fallow prior to planting Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data. Meteorological File  West Palm Beach, FL ( W12844) Maximum rainfall Interception storage of crop ( CINTCP) 0.15 PIC; confirmed using Table 5.4 from PRZM Manual ( Burns, 1992 and EPA, 1985)

Maximum Active Root Depth ( AMXDR) 45 cm http:// www. ces. uga. edu/ pubcd/ b1027_ w. html# Tra nsplant Maximum Canopy Coverage ( COVMAX) 70 Based on estimates from aerial photography; specific to peppers, other vegetable crops will require a different value Soil Surface Condition After Harvest ( ICNAH) 3 Plant residues are left behind until later in the year when tilled for next series of crops Date of Crop Emergence ( EMD, EMM, IYREM) 09/ 01 Florida Peppers ( Bell) Crop Profile, USDA, http:// pestdata. ncsu. edu/ cropprofiles/ docs/ FLpepp ers_ bell. html Date of Crop Maturity ( MAD, MAM, IYRMAT) 11/ 15 http:// edis. ifas. ufl. edu/ BODY_ CV130# TABLE_ 2 Date of Crop Harvest ( HAD, HAM, IYRHAR) 01/ 12 Florida Peppers ( Bell) Crop Profile, USDA, http:// pestdata. ncsu. edu/ cropprofiles/ docs/ FLpepp ers_ bell. html Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation SCS Curve Number ( CN) 91, 87, 88 Gleams Manual Table A. 3, Fallow = SR poor, Cropping and Residue = Row Crop SR/ poor ( USDA, 1990) Manning's N Value ( MNGN) 0.011 RUSLE Project; UC0BGBGC; Green Beans, conventional tillage; Tampa, FL ( USDA, 2000) USLE C Factor ( USLEC) 0.162  0.938 RUSLE Project; UC0BGBGC; Green Beans, conventional tillage; Tampa, FL, Variable with date ( USDA, 2000) Riviera Soil Parameters Total Soil Depth ( CORED) 100 cm Number of Horizons ( NHORIZ) 3 ( Top horizon split in two) NRCS, National Soils Characterization Database ( NRCS, 2001)

Horizon Thickness ( THKNS) 10 cm ( HORIZN = 1) 62 cm ( HORIZN = 2) 28 cm ( HORIZN = 3) Bulk Density ( BD) 1.65 g

cm 3 ( HORIZN = 1,2) 1.7 g

cm 3 ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001) http:// www. statlab. iastate. edu/ soils/ ssl/)

Ed Russell ( USDA_ NRCS, Fresno) Section II. D. 6  Page 36 of 120 Initial Water Content ( THETO) 0.073 cm3 H2O

cm3 soil ( HORIZN = 1,2) 0.211 cm3 H2O

cm3 soil ( HORIZN = 3) Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 2 cm ( HORIZN = 2,3) Field Capacity ( THEFC) 0.073 cm3 H2O

cm3 soil ( HORIZN = 1,2) 0.211 cm3 H2O

cm3 soil ( HORIZN = 3) Wilting Point ( THEWP) 0.023 cm3 H2O

cm3 soil ( HORIZN = 1,2) 0.091 cm3 H2O

cm3 soil ( HORIZN = 3) Organic Carbon Content ( OC) 1.16% ( HORIZN = 1,2) 0.174% ( HORIZN = 3)

4. Florida Sugarcane The field used to represent sugarcane production in Florida is located in Hendry County in Southwest Florida, although sugarcane production areas cover an area extending east to the Everglades Agricultural Area. According to the 1997 Census of Agriculture, Florida is the major producer ( yield) of sugarcane. Most sugarcane is grown on high organic " muck" soils; approximately 10 percent is grown on mineral soils. Sugarcane is grown on laser leveled fields by placing short seed " stalks" horizontally in the prepared field. Sugarcane is produced in a three to four year cycle with the first year planting referred to as the " plant cane" crop and successive years referred to as " stubble" or " ratoon" crops which are harvested from regrowth. Yields diminish with each successive crop. At the end of the third or fourth year, sugarcane is rotated to another crop before replanting. Row spacing is approximately 60 inches. Irrigation, when needed, may be accomplished by raising the ground water level through the use of " lateral" drainage systems controlled by locks and spaced from 100 feet to 300 feet apart. The soil selected to simulate the field is a Wabasso fine sand. Wabasso fine sand, is a sandy, siliceous, hyperthermic Alfic Alaquods. These soils are used for sugarcane production, but mainly citrus production and truck crops. Wabasso fine sand is a deep to very deep, poorly to very poorly drained, slow to ponded runoff, rapidly permeable in the top horizon and slow to very slowly permeable in the lower horizons soil that formed in sandy and loamy marine sediments. These soil are generally found on flatwoods, flood plains, and depressions and have slopes of 0 to 2 percent. The soil is extensive in Florida. Wabasso fine sand is a Hydrologic Group D soil.

PRZM 3.12 Scenario Input Parameters for Hendry County, Florida  Sugarcane Parameter Value Source Starting Date January 1, 1961 Meteorological File  Miami, FL ( W12839) Ending Date December 31, 1990 Meteorological File  Miami, FL ( W12839) Pan Evaporation Factor ( PFAC) 0.78 PRZM Manual Figure 5.1 ( EPA, 1998) Section II. D. 6  Page 37 of 120 Snowmelt Factor ( SFAC) 0.0 cm C 1 Does not snow in Southern Florida such that accumulation is expected Minimum Depth of Evaporation ( ANETD) 33.0 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.1 tons EI 1* GLEAMS Manual, table of Representative Soils ( USDA, 1990) USLE LS Factor ( USLELS) 0.093 GLEAMS Manual, table of Representative Soils ( USDA, 1990) USLE P Factor ( USLEP) 1.0 Assume no practice under trees.

Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA, 1999) NRCS Hyetograph ( IREG) 4 PRZM Manual Figure 5.12 ( EPA, 1998)

Slope ( SLP) 1% Mid point of soil series range ( EPA, 2001) Hydraulic Length ( HL) 464 m Shipman Reservoir ( EPA, 1999) Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops ( EPA, 2001) Initial Surface Condition ( ISCOND) 1 Set to represent fallow field Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data. Meteorological File  Miami, FL ( W12839) Maximum rainfall interception storage of crop ( CINTCP) 0.1 Set similar to LA Sugarcane; sugarcane is a grass PIC ( Burns, 1998)

Maximum Active Root Depth ( AMXDR) 100 cm Set to maximum of soil profile. http:// edis. ifas. ufl. edu Maximum Canopy Coverage ( COVMAX) 100 Set to default for row crops ( EPA, 2001)

Soil Surface Condition After Harvest ( ICNAH) 3 Default for sugarcane while under 3 4 yr cycle. After cycle, rotate to new crop.. Date of Crop Emergence ( EMD, EMM, IYREM) 01/ 01 typically planted August thru January, See Sugarcane Handbook http:// edis. ifas. ufl. edu/

Date of Crop Maturity ( MAD, MAM, IYRMAT) 01/ 06 typically harvested October thru March, See Sugarcane Handbook http:// edis. ifas. ufl. edu/

Date of Crop Harvest ( HAD, HAM, IYRHAR) 15/ 12 dates were chosen such that cycle would remain in a single calendar year and still remain within the typical range. See Sugarcane Handbook http:// edis. ifas. ufl. edu/ Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation Section II. D. 6  Page 38 of 120 SCS Curve Number ( CN) 94, 91, 92 Gleams Manual Table A. 3, Fallow = SR/ poor; Cropping and Residue = Row Crop, SR/ poor condition ( USDA, 1990) Manning's N Value ( MNGN) 0.014 RUSLE Project; UC0SCSCC; Sugarcane, conventional tillage, Tampa ( USDA, 2000) USLE C Factor ( USLEC) 0.194  0.717 RUSLE Project; Variable with date, UC0SCSCC; Sugarcane, conventional tillage, Tampa ( USDA, 2000) Wabasso Soil Parameters Parameter Value Verification Source Total Soil Depth ( CORED) 100 cm Number of Horizons ( NHORIZ) 2 ( Base horizons) NRCS, National Soils Characterization Database ( NRCS, 2001)

Horizon Thickness ( THKNS) 10 cm ( HORIZN = 1) 90 cm ( HORIZN = 2) Bulk Density ( BD) 1.45 g cm 3 ( HORIZN = 1) 1.75 g cm 3 ( HORIZN = 2) Initial Water Content ( THETO) 0.066 cm3 H2O cm3 soil ( HORIZN = 1) 0.178 cm3 H2O cm3 soil ( HORIZN = 2) Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 5 cm ( HORIZN = 2) Field Capacity ( THEFC) 0.066 cm3 H2O cm3 soil ( HORIZN = 1) 0.178 cm3 H2O cm3 soil ( HORIZN = 2) Wilting Point ( THEWP) 0.036 cm3 H2O cm3 soil ( HORIZN = 1) 0.078 cm3 H2O cm3 soil ( HORIZN = 2) Organic Carbon Content ( OC) 2.32% ( HORIZN = 1) 0.29% ( HORIZN = 2) NRCS, National Soils Characterization Database ( NRCS, 2001) http:// www. statlab. iastate. edu/ soils/ ssl/)

5. Florida Sweet Corn The field used to represent sweet corn production in Florida is located in Palm Beach County in Southeast Florida, although sweet corn production occurs throughout Florida. According to the 1997 Census of Agriculture, Florida is the major producer of fresh market sweet corn in the U. S. Sweet corn is extensively grown on " muck soils" ( approximately 75%). Typical planting distances are 30 inches between rows and 6 to 8 inches between plants. Sweet corn in Florida is produced using several types of irrigation systems. The soil selected to simulate the field is a Riviera sand. Riviera sand is a loamy, siliceous, active, hyperthermic Arenic Glossaqualfs. These soils are often used for truck crop ( including sweet corn) and citrus production. Riviera sand is a deep, poorly drained, slow runoff, slowly to very slowly permeable soil that formed in stratified marine sandy and loamy sediments on the Lower Coastal Plain. These soil are generally Section II. D. 6  Page 39 of 120 found on broad, low flats and in depressions and have slopes generally less than 2 percent. The soil is of moderate extent. Riviera sand is a Hydrologic Group C soil.

PRZM 3.12 Scenario Input Parameters for Palm Beach County, Florida  Sweet Corn Parameter Value Source Starting Date January 1, 1961 Meteorological File  West Palm Beach, FL ( W12844) Ending Date December 31, 1990 Meteorological File  West Palm Beach, FL ( W12844) Pan Evaporation Factor ( PFAC) 0.78 PRZM Manual Figure 5.1 ( EPA, 1998)

Snowmelt Factor ( SFAC) 0.0 cm C 1 No appreciable snow accumulation occurs in this part of Florida Minimum Depth of Evaporation ( ANETD) 33.0 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.03 tons EI 1* PRZM Input Collator ( Burns, 1992) and FARM Manual ( EPA, 1985) USLE LS Factor ( USLELS) 0.2 Haan and Barfield, 1979 USLE P Factor ( USLEP) 1.0 PRZM Manual ( EPA, 1998)

Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA, 1999)

NRCS Hyetograph ( IREG) 4 PRZM Manual Figure 5.12 ( EPA, 1998) Slope ( SLP) 1% Mid point of soil series range ( EPA, 2001) Hydraulic Length ( HL) 464 m Shipman Reservoir ( EPA, 1999) Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops ( EPA, 2001) Initial Surface Condition ( ISCOND) 1 Field are fallow prior to planting Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data. Meteorological File Maximum rainfall interception storage of crop ( CINTCP) 0.15 PIC; confirmed using Table 5.4 from PRZM Manual ( Burns, 1992 and EPA, 1985)

Maximum Active Root Depth ( AMXDR) 100 cm Set to profile depth. Roots can exceed 150 cm.

Maximum Canopy Coverage ( COVMAX) 90 PIC ( Burns, 1992)

Soil Surface Condition After Harvest ( ICNAH) 3 Plant residues are left behind until later in the year when tilled for next series of crops; rarely cucumbers. Date of Crop Emergence ( EMD, EMM, IYREM) 15/ 10 Date of Crop Maturity ( MAD, MAM, IYRMAT) 05/ 01 Date of Crop Harvest ( HAD, HAM, IYRHAR) 15/ 01 http:// ipmwww. ncsu. edu/ opmppiap/ subcrp. htm southern sweet corn cultivation cycle is generally between January and June; Maturation 64_ 90 days from seeding to harvest; Harvest occurs over a period of weeks to several months. Values set to cover rainy season Oct _ Feb. Section II. D. 6  Page 40 of 120 Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation SCS Curve Number ( CN) 91, 87, 88 Gleams Manual Table A. 3, Fallow = SR/ poor; Cropping and Residue = Row Crop, SR/ poor condition ( USDA, 1990) Manning's N Value ( MNGN) 0.011 RUSLE Project; UC0BGBGC; Green Beans, conventional tillage; Tampa, FL ( USDA, 2000) USLE C Factor ( USLEC) 0.162  0.938 RUSLE Project; Variable with date, UC0BGBGC; Green Beans, conventional tillage; Tampa, FL ( USDA, 2000) Riviera Soil Parameters Total Soil Depth ( CORED) 100 cm Number of Horizons ( NHORIZ) 3 ( Top horizon split in two) NRCS, National Soils Characterization Database ( NRCS, 2001)

Horizon Thickness ( THKNS) 10 cm ( HORIZN = 1) 62 cm ( HORIZN = 2) 28 cm ( HORIZN = 3) Bulk Density ( BD) 1.65 g

cm 3 ( HORIZN = 1,2) 1.7 g

cm 3 ( HORIZN = 3) Initial Water Content ( THETO) 0.073 cm3 H2O

cm3 soil ( HORIZN = 1,2) 0.211 cm3 H2O

cm3 soil ( HORIZN = 3) Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 2 cm ( HORIZN = 2,3) Field Capacity ( THEFC) 0.073 cm3 H2O

cm3 soil ( HORIZN = 1,2) 0.211 cm3 H2O

cm3 soil ( HORIZN = 3) Wilting Point ( THEWP) 0.023 cm3 H2O

cm3 soil ( HORIZN = 1,2) 0.091 cm3 H2O

cm3 soil ( HORIZN = 3) Organic Carbon Content ( OC) 1.16% ( HORIZN = 1,2) 0.174% ( HORIZN = 3) NRCS, National Soils Characterization Database ( NRCS, 2001) http:// www. statlab. iastate. edu/ soils/ ssl/)

Ed Russell ( USDA_ NRCS, Fresno) Section II. D. 6  Page 41 of 120 F. Mid South Region Scenario Documentation 1. Mississippi Cotton ( MScottonC)

The field used to represent cotton production in Mississippi is located in Yazoo County. According to the 1997 Census of Agriculture, Mississippi is ranked 4th in production and acreage of cotton in the U. S. The crop is generally planted in Spring ( late April) and harvested beginning in September. Row spacing is generally 38 inches with 3 4 plants per foot row. Row canopies tend to be very close to 100 percent, while the canopy between rows is much less. The crop may be grown under irrigation by furrow or canal systems. Most crops are planted by stale seedbed, no till, or conventional methods. The soil selected to simulate the field is a Loring silt loam. Loring silt loam is a finesilty mixed, active, thermic, Qxyaquic Fragiudalfs. Nearly all soils are cleared and used to grow cotton, small grains, soybeans, hay and pasture. Loring silt loam is a moderately well drained with a fragipan, medium to rapid runoff, moderate permeability above the fragipan and moderately slowly permeable in the fragipan soils formed in loess. They are located on level to strongly sloping uplands and stream terraces. Slopes are generally between 0 to 20 percent. The soils are extensive in the lower Mississippi drainage basin. Loring silt loam is a Hydrologic Group C soil.

PRZM 3.12 Scenario Input Parameters for Yazoo County, Mississippi  Cotton Parameter Value Source Starting Date January 1, 1961 Meteorological File   Jackson, MS ( W03940) Ending Date December 31, 1990 Meteorological File   Jackson, MS ( W03940) Pan Evaporation Factor ( PFAC) 0.76 PRZM Manual Figure 5.1 ( EPA, 1998)

Snowmelt Factor ( SFAC) 0.15 cm C 1 PRZM Manual Table 5.1 ( EPA, 1998)

Pan Factor Flag ( IPEIND) 2 PAN Evaporation data read from file Minimum Depth of Evaporation ( ANETD) 17.0 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.49 tons EI 1* EXPRES; PRZM Manual Table 5.3 ( EPA, 1998)

USLE LS Factor ( USLELS) 0.4 EXPRES; PRZM Manual Table 5.5 ( EPA, 1998)

USLE P Factor ( USLEP) 0.75 EXPRES; PRZM Manual Table 5.6 ( EPA, 1998)

Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA, 1999) NRCS Hyetograph ( IREG) 3 PRZM Manual Figure 5.12 ( EPA, 1998)

Slope ( SLP) 6% Selected according to QA/ QC Guidance ( EPA, 2001) Section II. D. 6  Page 42 of 120 Hydraulic Length ( HL) 464 m Shipman Reservoir ( EPA, 1999) Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops ( EPA, 2001) Initial Surface Condition ( ISCOND) 1 PRZM Input Collator ( Burns, 1992)

Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data. Meteorological File   Jackson, MS ( W03940) Maximum rainfall interception storage of crop ( CINTCP) 0.2 EXPRES; PRZM manual Table 5.4 ( EPA, 1998)

Maximum Active Root Depth ( AMXDR) 125 cm EXPRES; Value developed from field specific data. Maximum Canopy Coverage ( COVMAX) 98 EXPRES; Value developed from field specific data. Soil Surface Condition After Harvest ( ICNAH) 3 PRZM Input Collator ( Burns, 1992)

Date of Crop Emergence ( EMD, EMM, IYREM) 01/ 05 Date of Crop Maturity ( MAD, MAM, IYRMAT) 07/ 09 Date of Crop Harvest ( HAD, HAM, IYRHAR) 22/ 09 EXPRES and verified with Usual Planting and Harvest Dates for US Field Crops ( USDA, 1984)

Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation SCS Curve Number ( CN) 99, 93, 32 EXPRES; PRZM Manual Table 5.10_ 5.14 and Fig. 5.4; Field specific data. Manning's N Value ( MNGN) 0.014 RUSLE Project, PA6CTCTC: Cotton, conventional tillage, Holly Springs, MS ( USDA, 2000) USLE C Factor ( USLEC) 0.223  0.718 RUSLE Project; PA6CTCTC: Cotton, conventional tillage, Holly Springs, MS ( USDA, 2000) Loring Soil Parameters Total Soil Depth ( CORED) 155 cm Number of Horizons ( NHORIZ) 6 PIC ( Burns, 1992) Confirmed with: NRCS, National Soils Characterization Database ( NRCS, 2001)

Horizon Thickness ( THKNS) 13 cm ( HORIZN = 1) 23 cm ( HORIZN = 2) 33 cm ( HORIZN = 3) 30 cm ( HORIZN = 4) 23 cm ( HORIZN = 5) 33 cm ( HORIZN = 6) PIC ( Burns, 1992) Confirmed with: NRCS, National Soils Characterization Database ( NRCS, 2001) http:// www. statlab. iastate. edu/ soils/ ssl/) Section II. D. 6  Page 43 of 120 Bulk Density ( BD) 1.4 g cm 3 ( HORIZN = 1,2,3) 1.45 g cm 3 ( HORIZN = 4) 1.49 g cm 3 ( HORIZN = 5) 1.51 g cm 3 ( HORIZN = 6) Initial Water Content ( THETO) 0.385 cm3 H2O cm3 soil ( HORIZN = 1) 0.370 cm3 H2O cm3 soil ( HORIZN = 2,3) 0.340 cm3 H2O cm3 soil ( HORIZN = 4) 0.335 cm3 H2O cm3 soil ( HORIZN = 5) 0.343 cm3 H2O cm3 soil ( HORIZN = 6) Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 1.0 cm ( HORIZN = 2) 11 cm ( HORIZN = 3) 10 cm ( HORIZN = 4) 23 cm ( HORIZN = 5) 33 cm ( HORIZN = 6) Field Capacity ( THEFC) 0.385 cm3 H2O cm3 soil ( HORIZN = 1) 0.370 cm3 H2O cm3 soil ( HORIZN = 2,3) 0.340 cm3 H2O cm3 soil ( HORIZN = 4) 0.335 cm3 H2O cm3 soil ( HORIZN = 5) 0.343 cm3 H2O cm3 soil ( HORIZN = 6) Wilting Point ( THEWP) 0.151 cm3 H2O cm3 soil ( HORIZN = 1) 0.146 cm3 H2O cm3 soil ( HORIZN = 2,3) 0.125 cm3 H2O cm3 soil ( HORIZN = 4) 0.137 cm3 H2O cm3 soil ( HORIZN = 5) 0.147 cm3 H2O cm3 soil ( HORIZN = 6) Organic Carbon Content ( OC) 1.28% ( HORIZN = 1) 0.49% ( HORIZN = 2) 0.16% ( HORIZN = 3) 0.12% ( HORIZN = 4) 0.07% ( HORIZN = 5) 0.06% ( HORIZN = 6)

2. Mississippi Corn ( MScornC) Section II. D. 6  Page 44 of 120 The field used to represent corn production in Mississippi is located in the Southern Mississippi Valley Uplands. According to the 1997 Census of Agriculture, Mississippi is not a major corn producing state in the U. S. ( not among the top 20 states) with approximately 600,000 acres in production. The crop is generally planted in the early Spring ( April) and harvested beginning in August. Continuous corn is practice is much of the region, however, rotation with other crops such as soybean is the practiced as well. Most of the corn is planted for feed grain. Planting depth and row spacing ( generally 30 inches) follows general practices for the U. S. Conventional tillage dominates with more than 50 percent of the practice, followed by conservation tillage, no_ tillage, and ridge tillage. The crop is rarely grown under irrigation. The soil selected to simulate the field is a benchmark soil, Grenada silt loam. Grenada silt loam is a finesilty mixed, active, thermic Oxyaquic Fraglossudalfs. Most of the soil is used for the production of row crops such as corn, cotton, and soybeans, the principal crops. Grenada silt loam is a very deep, moderately well drained, medium to slow runoff, moderately permeable above a fragipan and slow in the fragipan soil. The fragipan is at a depth of about two feet. The soils formed in loess. They are located on uplands and stream terraces of low relief in the Southern Mississippi Valley Silty Uplands. Slopes are generally between 0 to 8 percent, but may range to 12 percent. The soils are extensive throughout the region. Grenada silt loam is a Hydrologic Group C soil.

PRZM 3.12 Scenario Input Parameters for Southern Mississippi Valley Uplands, Mississippi  Corn Parameter Value Source Starting Date January 1, 1961 Meteorological File   Jackson, MS ( W03940) Ending Date December 31, 1990 Meteorological File   Jackson, MS ( W03940) Pan Evaporation Factor ( PFAC) 0.75 PRZM Manual Figure 5.1 ( EPA, 1998)

Snowmelt Factor ( SFAC) 0.25 cm C 1 PRZM Manual Table 5.1 ( EPA, 1998)

Minimum Depth of Evaporation ( ANETD) 25.0 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.43 tons EI 1* GLEAMS Table of Representative Soils ( USDA, 1990) USLE LS Factor ( USLELS) 0.221 GLEAMS Table of Representative Soils ( USDA, 1990) USLE P Factor ( USLEP) 1.00 PRZM Manual ( EPA, 1998)

Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA, 1999) NRCS Hyetograph ( IREG) 4 PRZM Manual Figure 5.12 ( EPA, 1998)

Slope ( SLP) 6% Mid point of series range. Selected according to QA/ QC Guidance ( EPA, 2001) Hydraulic Length ( HL) 464 m Shipman Reservoir ( EPA, 1999) Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops ( EPA, 2001) Section II. D. 6  Page 45 of 120 Initial Surface Condition ( ISCOND) 1 PRZM Input Collator ( Burns, 1992)

Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data. Meteorological File   Jackson, MS ( W03940) Maximum rainfall interception storage of crop ( CINTCP) 0.25 PRZM Table 5.4 ( EPA, 1998)

Maximum Active Root Depth ( AMXDR) 90 cm PRZM Input Collator; ( Burns, 1992); PRZM Table 5.9 ( EPA, 1998) Maximum Canopy Coverage ( COVMAX) 100 PRZM Input Collator ( Burns, 1992); Set to default for most row crops ( EPA, 2001) Soil Surface Condition After Harvest ( ICNAH) 3 PRZM Input Collator, PIC ( Burns, 1992)

Date of Crop Emergence ( EMD, EMM, IYREM) 11/ 04 Date of Crop Maturity ( MAD, MAM, IYRMAT) 22/ 08 Date of Crop Harvest ( HAD, HAM, IYRHAR) 02/ 09 Usual Planting and Harvest Dates for US Field Crops ( USDA, 1984)

Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation SCS Curve Number ( CN) 91, 87, 88 Gleams Manual Table A. 3, Fallow = SR/ poor, Cropping and Residue = Row Crop, SR/ Poor condition ( USDA, 1990) Manning's N Value ( MNGN) 0.014 RUSLE Project, OA6CGSBC; Corn, grain, conventional tillage, Natchez, MS ( USDA, 2000) USLE C Factor ( USLEC) 0.024  0.848 RUSLE Project; OA6CGSBC; Corn, grain, conventional tillage, Natchez, MS ( USDA, 2000) Grenada Soil Parameters Total Soil Depth ( CORED) 100 cm Number of Horizons ( NHORIZ) 4 ( 3 Base, Top horizon split in two) PIC ( Burns, 1992) Confirmed with: NRCS, National Soils Characterization Database ( NRCS, 2001)

Horizon Thickness ( THKNS) 10 cm ( HORIZN = 1) 44 cm ( HORIZN = 2) 8 cm ( HORIZN = 3) 38 cm ( HORIZN = 4) Bulk Density ( BD) 1.7 g

cm 3 ( HORIZN = 1, 2) 1.8 g

cm 3 ( HORIZN = 3,4) PIC ( Burns, 1992) Confirmed with: NRCS, National Soils Characterization Database ( NRCS, 2001) http:// www. statlab. iastate. edu/ soils/ ssl/) Section II. D. 6  Page 46 of 120 Initial Water Content ( THETO) 0.309 cm3 H2O

cm3 soil ( HORIZN = 1, 2) 0.304 cm3 H2O

cm3 soil ( HORIZN = 3) 0.216 cm3 H2O

cm3 soil ( HORIZN = 4) Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 2 cm ( HORIZN = 2,3,4) Field Capacity ( THEFC) 0.309 cm3 H2O

cm3 soil ( HORIZN = 1, 2) 0.304 cm3 H2O

cm3 soil ( HORIZN = 3) 0.216 cm3 H2O

cm3 soil ( HORIZN = 4) Wilting Point ( THEWP) 0.109 cm3 H2O

cm3 soil ( HORIZN = 1,2) 0.104 cm3 H2O

cm3 soil ( HORIZN = 3) 0.116 cm3 H2O

cm3 soil ( HORIZN = 4) Organic Carbon Content ( OC) 1.16% ( HORIZN = 1,2) 0.174% ( HORIZN = 3) 0.116% ( HORIZN = 4) Section II. D. 6  Page 47 of 120 G. Lower Midwest Region Scenario Documentation 1. South Texas Grapefruit ( STXgrapefrtCRA)

The field used to represent grapefruit production in South Texas is representative of a field in Hildago and Cameron counties, located in the Lower Rio Grande Valley region. The meteorological file, Brownsville, TX, represents the MLRA region 83D. In 2004, Texas ranked second behind Florida in acres producing Grapefruit. Texas contained 16 percent of the total acres of grapefruit production ( USDA 2004). Grapefruit trees are planted in rows 24 25 feet apart. Crops are irrigated ( Texas A& M 2002) and pruned to maintain a height of approximately 15 feet. In the Lower Rio Grande Valley region of Texas, grapefruit trees bloom from March 10 20. Fruit matures between October and December and is harvested from October to May ( Personal communication 2004). The soil in Hidalgo and Cameron counties is alluvial, being derived from the Rio Grande ( USDA 1997). Thus there is no dominant soil type ( range of coverages: 0.1 13.2%). In the Lower Rio Grande Valley region, several soil types support citrus production ( Brennan, Delfinia, Hidalgo, Willacy) ( Texas A& M 2002). For this scenario, Hidalgo sandy clay loam was selected as a representative soil type because it has significant yields of citrus and was recommended by an extension agent as being the most commonly associated soil with citrus ( Personal communication 2004). Hidalgo sandy clay loam is a hydrologic group B soil that is classified as fine loamy, mixed, active, hyperthermic typic calciustolls. The Hidalgo series of soils is deep, well drained, moderately permeable and formed in calcareous loamy sediments. These soils occur on nearly level to gently sloping uplands with slopes of 0 5 percent. This soil type occurs on the Rio Grande Plain of Texas and Mexico ( possibly). This soil is mostly used for irrigated crop production including cotton, grain sorghum, vegetables, sugar cane and citrus ( USDA1997).

PRZM 3.12 Scenario Input Parameters for Hidalgo/ Cameron Counties, Texas  Grapefruit Parameter Value Source Starting Date January 1, 1961 Meteorological File  Brownsville, Cameron County, Texas: W12919 Ending Date December 31, 1990 Meteorological File  Brownsville, Cameron County, Texas: W12919 Pan Evaporation Factor ( PFAC) 0.69 PRZM Manual Figure 5.1 ( EPA, 1998)

Snowmelt Factor ( SFAC) 0 cm C 1 PRZM Manual Table 5.1 ( EPA, 1998)

Minimum Depth of Evaporation ( ANETD) 32.5 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.32 tons EI 1* Taken from NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/) Section II. D. 6  Page 48 of 120 USLE LS Factor ( USLELS) 0.37 Based on slope taken from NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/) , PRZM manual length 400 m, 2.5% slope USLE P Factor ( USLEP) 1 contour plowing is not common due to 0 5% slope ( consulted with extension agent) Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA 2004) NRCS Hyetograph ( IREG) 3 PRZM Manual Figure 5.12 ( EPA, 1998)

Slope ( SLP) 2.5% From http:// soils. usda. gov/ official soil series description ( slope range = 0 5%) Hydraulic Length ( HL) 356 ( pond) 464 ( reservoir) Shipman Reservoir ( EPA 2004)

Irrigation Flag ( IRFLAG) 0 From PRZM Scenario Guidance ( 2004)

Irrigation Type ( IRTYP) Not applicable Leaching Factor ( FLEACH) Not applicable Fraction of Water Capacity when Irrigation is Applied ( PCDEPL) Not applicable Maximum Rate at which Irrigation is Applied ( RATEAP) Not applicable Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops ( EPA 2004) Initial Surface Condition ( ISCOND) 3 PRZM Scenario Guidance ( 2004)

Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data.

Maximum rainfall interception storage of crop ( CINTCP) 0.25 cm PRZM Manual ( Carsel et al., 1998)

Maximum Active Root Depth ( AMXDR) 243.8 cm Consulted extension agent ( Max rooting depth = 5  8 ft) Maximum Canopy Coverage ( COVMAX) 75% Consulted extension agent Soil Surface Condition After Harvest ( ICNAH) 3 PRZM Manual ( Carsel et al., 1998), 3 = residue Date of Crop Emergence ( EMD, EMM, IYREM) 16/ 3/ 61 Consulted extension agent Date of Crop Maturity ( MAD, MAM, IYRMAT) 1/ 11/ 61 Consulted extension agent Section II. D. 6  Page 49 of 120 Date of Crop Harvest ( HAD, HAM, IYRHAR) 1/ 2/ 61 Consulted extension agent Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation SCS Curve Number ( CN) 67, 74, 78 Gleams Manual Table A. 3, ( Hydrological soil B) meadow ( USDA, 1990) Manning's N Value ( MNGN) .014 . RUSLE Project, TX Galveston, Citrus, ( T95CBCBC)

USLE C Factor ( USLEC) .374 .385 .383 .391 .407 .422 .423 .437 .458 .456 .464 .475 .442 .424 .434 .439 .442 .325 .340 .352 .363 .371 .378 .384 .389 .362 RUSLE Project, TX Galveston, Citrus, ( T95CBCBC)

Soil Parameters Total Soil Depth ( CORED) 160 cm http:// soils. usda. gov/ ( 63 inches)

Number of Horizons ( NHORIZ) 4 ( top HORIZN split in 2) NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/) Horizon Thickness ( THKNS) 10 cm ( HORIZN = 1) 21 cm ( HORIZN = 2) 25 cm ( HORIZN = 3) 104 cm ( HORIZN = 3) Bulk Density ( BD) 1.5g cm 3 ( HORIZN = 1) 1.5 g cm 3 ( HORIZN = 2) 1.325 g cm 3 ( HORIZN = 3) 1.35 g cm 3 ( HORIZN = 4) NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/

Initial Water Content ( THETO) 0.30 cm3 H20 cm3 soil ( HORIZN = 1 4) Field Capacity values, PRZM Scenario Guidance ( 2004) Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 1 cm ( HORIZN = 2) 1 cm ( HORIZN = 3) 2 cm ( HORIZN = 4) PRZM Scenario Guidance ( 2004)

Field Capacity ( THEFC) 0.30 cm3 H20 cm3 soil GLEAMS Table H 3 ( 1990)

Wilting Point ( THEWP) 0.18 cm3 H20 cm3 soil GLEAMS Table H 3 ( 1990) Organic Carbon Content ( OC) 1.2% ( HORIZN = 1) 1.2% ( HORIZN = 2) 0.45% ( HORIZN = 3) 0.18% ( HORIZN = 4) NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/); Adjusted using the relationship % OC = 0.6 x % Organic Matter ( Doucette 2000)

2. South Texas Cotton ( STXcottonCRA)

The field used to represent cotton production in South Texas is representative of a field in Hildago and Cameron counties, located in the Lower Rio Grande Valley region. The meteorological file, Brownsville, TX, represents the MLRA region 83D. Texas Section II. D. 6  Page 50 of 120 ranks first in production of cotton in the U. S. Cotton is the leading cash crop in Texas with a total economic impact of 5.2 billion dollars in the state ( NSF 1999). Agricultural methods ( irrigation, planting times, cotton types, harvesting methods) vary significantly from region to region. The Northern High Plains grows approximately 64 percent of Texas corn with 3 percent being grown in the Lower Rio Grande Valley region. In the Lower Rio Grande Valley region of Texas, cotton is planted between February and March. Corn is generally irrigated. Cotton is harvested in Texas between August and December ( NSF 1999). The soil in Hildago and Cameron counties is alluvial, being derived from the Rio Grande ( USDA 1997). Thus there is no dominant soil type ( range of coverages: 0.1 13.2%). For this scenario, Harlingen Clay was selected as a representative soil type because it has significant yields of cotton and has the largest percent coverage of a hydrologic group C or D soil for Hildago ( 4.8 %) and Cameron ( 6.6 %) counties ( USDA 2004). Harlingen Clay is a hydrologic group D soil that is classified as very fine, smectitic, hyperthermic sodic haplusterts. The Harlingen series of soils is deep, moderately well drained, very slowly permeable soils that formed in clayey sediments. These soils have slopes of 0 1 percent and occur on stream terraces and deltas along the lower portions of the Rio Grande River and its tributaries in south Texas and Mexico. This soil is mostly used for irrigated crop land including cotton and cool season vegetables ( USDA1997).

PRZM 3.12 Scenario Input Parameters for Hidalgo/ Cameron Counties, Texas  Cotton Parameter Value Source Starting Date January 1, 1961 Meteorological File  Brownsville, Cameron County, Texas: W12919 Ending Date December 31, 1990 Meteorological File  Brownsville, Cameron County, Texas: W12919 Pan Evaporation Factor ( PFAC) 0.69 PRZM Manual Figure 5.1 ( EPA, 1998)

Snowmelt Factor ( SFAC) 0.0 cm C 1 PRZM Manual Table 5.1 ( EPA, 1998)

Minimum Depth of Evaporation ( ANETD) 32.5 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.32 tons EI 1* Taken from NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/) USLE LS Factor ( USLELS) 0.15 Based on slope taken from NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/) , PRZM manual length 400 m, 0.5% slope USLE P Factor ( USLEP) 1 contour plowing is not common due to 0 1% slope ( consulted with extension agent) Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA 2004) NRCS Hyetograph ( IREG) 3 PRZM Manual Figure 5.12 ( EPA, 1998)

Slope ( SLP) 0.5% From http:// soils. usda. gov/ official soil series description ( slope range = 0 1%) Section II. D. 6  Page 51 of 120 Hydraulic Length ( HL) 356 ( pond) 464 ( reservoir) Shipman Reservoir ( EPA 2004)

Irrigation Flag ( IRFLAG) 0 From PRZM Scenario Guidance ( 2004)

Irrigation Type ( IRTYP) Not applicable Leaching Factor ( FLEACH) Not applicable Fraction of Water Capacity when Irrigation is Applied ( PCDEPL) Not applicable Maximum Rate at which Irrigation is Applied ( RATEAP) Not applicable Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops ( EPA 2004) Initial Surface Condition ( ISCOND) 2 PRZM Scenario Guidance ( 2004)

Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data.

Maximum rainfall interception storage of crop ( CINTCP) 0.20 cm PRZM Manual ( Carsel et al., 1998)

Maximum Active Root Depth ( AMXDR) 60 cm PRZM Manual ( Carsel et al., 1998)

Maximum Canopy Coverage ( COVMAX) 100% PRZM Manual ( Carsel et al., 1998)

Soil Surface Condition After Harvest ( ICNAH) 2 PRZM Manual ( Carsel et al., 1998), 2 = cover crop consulted with extension agent, crops are rotated Date of Crop Emergence ( EMD, EMM, IYREM) 16/ 3/ 61 corn is planted late January Late February ( TX extension crop profile) + emergence of 5 15 days ( PRZM manual)

Date of Crop Maturity ( MAD, MAM, IYRMAT) 20/ 7/ 61 mature 110 130 days from planting ( PRZM manual)

Date of Crop Harvest ( HAD, HAM, IYRHAR) 15/ 10/ 61 harvest from August 1 to December 20 ( PRZM manual, Table 5 9)

Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation SCS Curve Number ( CN) 88, 89, 90 Gleams Manual Table A. 3, ( Hydrological soil D) Row Crop, SR, good hydrologic condition ( USDA, 1990) Manning's N Value ( MNGN) .014. RUSLE Project, TX Galveston Cotton, ( T95CTCTC) Section II. D. 6  Page 52 of 120 USLE C Factor ( USLEC) .628 .654 .678 .697 .712 .727 .743 .784 .809 .808 .776 .639 .506 .384 .299 .295 .337 .412 .432 .358 .442 .494 .542 .585 .621 RUSLE Project, TX Galveston Cotton, ( T95CTCTC)

Soil Parameters Total Soil Depth ( CORED) 180 cm http:// soils. usda. gov/

Number of Horizons ( NHORIZ) 4 ( top HORIZN split in 2) NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/) Horizon Thickness ( THKNS) 10 cm ( HORIZN = 1) 18 cm ( HORIZN = 2) 61 cm ( HORIZN = 3) 91 cm ( HORIZN = 4) Bulk Density ( BD) 1.45g cm 3 ( HORIZN = 1) 1.45g cm 3 ( HORIZN = 2) 1.40 g cm 3 ( HORIZN = 3) 1.55 g cm 3 ( HORIZN = 4) NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/

Initial Water Content ( THETO) 0.39 cm3 H20 cm3 soil ( HORIZN = 1 4) Field Capacity values, PRZM Scenario Guidance ( 2004) Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 1 cm ( HORIZN = 2) 1 cm ( HORIZN = 3) 1 cm ( HORIZN = 4) PRZM Scenario Guidance ( 2004)

Field Capacity ( THEFC) 0.39 cm3 H20 cm3 soil GLEAMS Table H 3 ( 1990)

Wilting Point ( THEWP) 0.28 cm3 H20 cm3 soil GLEAMS Table H 3 ( 1990) Organic Carbon Content ( OC) 1.2% ( HORIZN = 1) 1.2% ( HORIZN = 2) 0.9% ( HORIZN = 3) 0.45% ( HORIZN = 4) NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/); Adjusted using the relationship % OC = 0.6 x % Organic Matter ( Doucette 2000)

3. South Texas Vegetables ( STXvegetblCRA)

The field used to represent vegetable production in South Texas is representative of a field in Hildago and Cameron counties, located in the Lower Rio Grande Valley region. The meteorological file, Brownsville, TX, represents the MLRA region 83D. Specifically, the vegetable scenario represents carrot, onion and cabbage production in the state. Texas produces 3 percent of the U. S. commercially grown carrots. The Lower Rio Grande Region produces approximately 50 percent of Texas carrots. Carrot seed is often precision planted at 1/ 8 1/ 4 inches deep between July and November. They are mechanically harvested from December to May ( NSF 2003 a). Texas produces 7 percent of the U. S. commercially grown onions. The Lower Rio Grande Region produces approximately 80 percent of Texas onions. Onion seed is often precision planted at 1/ 4 3/ 4 inches deep, on 38 40 inch raised beds in October. Mechanical harvest begins 120 210 days after planting, when the tops 50 80% of the tops fall over. They are mechanically harvested from December to May ( NSF 2003 b). Texas produces 15 percent of the U. S. commercially grown cabbage. The Lower Rio Grande Region produces approximately 50 percent of Texas cabbage. Cabbage seed is often planted at 6 Section II. D. 6  Page 53 of 120 15 inches apart ( NSF 2003 c). The soil in Hildago and Cameron counties is alluvial, being derived from the Rio Grande ( USDA 1997). Thus there is no dominant soil type ( range of coverages: 0.1 13.2%). For this scenario, Harlingen Clay was selected as a representative soil type because it supports vegetable production and has largest percent coverage of a hydrologic group C or D soil for Hildago ( 4.8 %) and Cameron ( 6.6 %) counties ( USDA 2004). Harlingen Clay is a hydrologic group D soil that is classified as very fine, smectitic, hyperthermic sodic haplusterts. The Harlingen series of soils is deep, moderately well drained, very slowly permeable soils that formed in clayey sediments. These soils have slopes of 0 1 percent and occur on stream terraces and deltas along the lower portions of the Rio Grande River and its tributaries in south Texas and Mexico. This soil is mostly used for irrigated crop land including cotton and cool season vegetables ( USDA 1997).

PRZM 3.12 Climate and Time Parameters for Hidalgo/ Cameron Counties, Texas  Vegetable Parameter Value Source Starting Date January 1, 1961 Meteorological File  Brownsville, Cameron County, Texas: W12919 Ending Date December 31, 1990 Meteorological File  Brownsville, Cameron County, Texas: W12919 Pan Evaporation Factor ( PFAC) 0.69 PRZM Manual Figure 5.1 ( EPA, 1998)

Snowmelt Factor ( SFAC) 0 cm C 1 PRZM Manual Table 5.1 ( EPA, 1998)

Minimum Depth of Evaporation ( ANETD) 32.5 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.32 tons EI 1* Taken from NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/) USLE LS Factor ( USLELS) 0.15 Based on slope taken from NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/) , PRZM manual length 400 m, 0.5% slope USLE P Factor ( USLEP) 1 contour plowing is not common due to 0 1% slope ( consulted with extension agent) Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA 2004) NRCS Hyetograph ( IREG) 3 PRZM Manual Figure 5.12 ( EPA, 1998)

Slope ( SLP) 0.5% From http:// soils. usda. gov/ official soil series description ( slope range = 0 1%) Hydraulic Length ( HL) 356 ( pond) 464 ( reservoir) Shipman Reservoir ( EPA 2004)

Irrigation Flag ( IRFLAG) 0 From PRZM Scenario Guidance ( 2004)

Irrigation Type ( IRTYP) Not applicable Leaching Factor ( FLEACH) Not applicable Section II. D. 6  Page 54 of 120 Fraction of Water Capacity when Irrigation is Applied ( PCDEPL) Not applicable Maximum Rate at which Irrigation is Applied ( RATEAP) Not applicable Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops (. EPA 2004) Initial Surface Condition ( ISCOND) 2 Consulted extension agent, crops are rotated Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data.

Maximum rainfall interception storage of crop ( CINTCP) 0.25 cm PRZM Manual ( Carsel et al., 1998)

Maximum Active Root Depth ( AMXDR) 38.1 cm Consulted extension agent Maximum Canopy Coverage ( COVMAX) 80% Consulted extension agent Soil Surface Condition After Harvest ( ICNAH) 2 PRZM Manual ( Carsel et al., 1998)

Date of Crop Emergence ( EMD, EMM, IYREM) 1/ 10/ 61 Consulted extension agent Date of Crop Maturity ( MAD, MAM, IYRMAT) 1/ 3/ 61 Consulted extension agent Date of Crop Harvest ( HAD, HAM, IYRHAR) 15/ 3/ 61 Consulted extension agent Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation SCS Curve Number ( CN) 88, 89, 90 Gleams Manual Table A. 3, ( Hydrological soil D), Row crop, SR, good hydrologic conditions ( USDA, 1990) Manning's N Value ( MNGN) .011 . RUSLE Project, TX Galveston, Onion ( T95ONONC) USLE C Factor ( USLEC) .623 .673 .715 .746 .760 .698 .813 .816 .806 .785 .760 .726 .692 .590 .666 .729 .782 .824 .857 .801 .902 .901 .885 .842 .786 .742 .699 .697 .712 .574 RUSLE Project, TX Galveston, Onion ( T95ONONC)

Soil Parameters Total Soil Depth ( CORED) 180 cm http:// soils. usda. gov/ ( 71 inches)

Number of Horizons ( NHORIZ) 4 ( top HORIZN split in 2) NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/) Section II. D. 6  Page 55 of 120 Horizon Thickness ( THKNS) 10 cm ( HORIZN = 1) 18 cm ( HORIZN = 2) 61 cm ( HORIZN = 3) 91 cm ( HORIZN = 4) Bulk Density ( BD) 1.45g cm 3 ( HORIZN = 1) 1.45g cm 3 ( HORIZN = 2) 1.40 g cm 3 ( HORIZN = 3) 1.55 g cm 3 ( HORIZN = 4) NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/)

Initial Water Content ( THETO) 0.39 cm3 H20 cm3 soil ( HORIZN = 1 4) Field Capacity values, PRZM Scenario Guidance ( 2004) Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 1 cm ( HORIZN = 2) 1 cm ( HORIZN = 3) 1 cm ( HORIZN = 4) PRZM Scenario Guidance ( 2004)

Field Capacity ( THEFC) 0.39 cm3 H20 cm3 soil GLEAMS Table H 3 ( 1990)

Wilting Point ( THEWP) 0.28 cm3 H20 cm3 soil GLEAMS Table H 3 ( 1990) Organic Carbon Content ( OC) 1.2% ( HORIZN = 1) 1.2% ( HORIZN = 2) 0.9% ( HORIZN = 3) 0.45% ( HORIZN = 4) NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/); Adjusted using the relationship % OC = 0.6 x % Organic Matter ( Doucette 2000)

4. South Texas Melon ( STXmelonCRA)

The field used to represent melon production in South Texas is representative of a field in Hildago and Cameron counties, located in the Lower Rio Grande Valley region. The meteorological file, Brownsville, TX, represents the MLRA region 83D. Specifically, the melon scenario represents cantaloupe, honeydew melon and watermelon production in the state. Texas produces 9 percent and 10 percent of the U. S. commercially grown cantaloupe and honeydew melon, respectively ( NSF 1999). Approximately 50 percent of the state's cantaloupe and honeydew melon is grown in the Lower Rio Grande Region. Seeds are planted ½  1 inch deep 8 12 inches apart in 78 80 inch beds or 12 24 inches apart in 2 lines on 78 80 inch beds. Planting is from the third week in January to the second week of February. Second and third plantings are done two weeks after the previous plantings. Cantaloupe and honeydew melon are harvested 85 95 days after planting ( NSF 2000). Texas produces 20 percent of the U. S. commercially grown watermelons, ranking number one in the country ( NSF 1999). Hildago is the number one county in Texas for watermelon production. Seeds are planted 3/ 4  1 inch deep 3 feet apart on 6 foot beds ( NSF 2003). The soil in Hildago and Cameron counties is alluvial, being derived from the Rio Grande ( USDA 1997). Thus there is no dominant soil type ( range of coverages: 0.1 13.2%). For this scenario, Harlingen Clay was selected as a representative soil type because it supports melon growth and has the largest percent coverage of a hydrologic group C or D soil for Hildago ( 4.8 %) and Cameron ( 6.6 %) counties ( USDA 2004). Harlingen Clay is a hydrologic group D soil that is classified as very fine, smectitic, hyperthermic sodic haplusterts. The Harlingen series of soils is deep, moderately well drained, very slowly permeable soils that formed in clayey sediments. These soils have slopes of 0 1 percent and occur on stream terraces and deltas along the lower portions of the Rio Grande River Section II. D. 6  Page 56 of 120 and its tributaries in south Texas and Mexico. This soil is mostly used for irrigated crop land including cotton and cool season vegetables ( USDA1997).

PRZM 3.12 Scenario Input Parameters for Hidalgo/ Cameron Counties, Texas  Melon Parameter Value Source Starting Date January 1, 1961 Meteorological File  Brownsville, Cameron County, Texas: W12919 Ending Date December 31, 1990 Meteorological File  Brownsville, Cameron County, Texas: W12919 Pan Evaporation Factor ( PFAC) 0.69 PRZM Manual Figure 5.1 ( EPA, 1998)

Snowmelt Factor ( SFAC) 0 cm C 1 PRZM Manual Table 5.1 ( EPA, 1998)

Minimum Depth of Evaporation ( ANETD) 32.5 cm PRZM Manual Figure 5.2 ( EPA, 1998)

Erosion and Landscape Parameters Method to Calculate Erosion ( ERFLAG) 4 ( MUSS) PRZM Manual ( EPA, 1998)

USLE K Factor ( USLEK) 0.32 tons EI 1* Taken from NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/) USLE LS Factor ( USLELS) 0.15 Based on slope taken from NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/) , PRZM manual length 400 m, 0.5% slope USLE P Factor ( USLEP) 1 contour plowing is not common due to 0 1% slope ( consulted with extension agent) Field Area ( AFIELD) 172 ha Area of Shipman Reservoir watershed ( EPA 2004) NRCS Hyetograph ( IREG) 3 PRZM Manual Figure 5.12 ( EPA, 1998)

Slope ( SLP) 0.5% From http:// soils. usda. gov/ official soil series description ( slope range = 0 1%) Hydraulic Length ( HL) 356 ( pond) 464 ( reservoir) Shipman Reservoir ( EPA 2004)

Irrigation Flag ( IRFLAG) 0 From PRZM Scenario Guidance ( 2004)

Irrigation Type ( IRTYP) Not applicable Leaching Factor ( FLEACH) Not applicable Fraction of Water Capacity when Irrigation is Applied ( PCDEPL) Not applicable Maximum Rate at which Irrigation is Applied ( RATEAP) Not applicable Crop Parameters Initial Crop ( INICRP) 1 Set to one for all crops ( EPA. 2001) Initial Surface Condition ( ISCOND) 2 PRZM Scenario Guidance ( 2004) Section II. D. 6  Page 57 of 120 Number of Different Crops ( NDC) 1 Set to crops in simulation  generally one Number of Cropping Periods ( NCPDS) 30 Set to weather data.

Maximum rainfall interception storage of crop ( CINTCP) 0.25 cm PRZM Manual ( Carsel et al., 1998)

Maximum Active Root Depth ( AMXDR) 61 cm Consulted extension agent Maximum Canopy Coverage ( COVMAX) 100% Consulted extension agent Soil Surface Condition After Harvest ( ICNAH) 2 PRZM Manual ( Carsel et al., 1998)

Date of Crop Emergence ( EMD, EMM, IYREM) 1/ 2/ 61 Consulted extension agent Date of Crop Maturity ( MAD, MAM, IYRMAT) 1/ 5/ 61 Consulted extension agent Date of Crop Harvest ( HAD, HAM, IYRHAR) 7/ 5/ 61 Consulted extension agent Maximum Dry Weight ( WFMAX) 0.0 Set to " 0" Not used in simulation SCS Curve Number ( CN) 88, 89, 90 Gleams Manual Table A. 3, ( Hydrological soil D), Row crop, SR, good hydrologic conditions ( USDA, 1990) Manning's N Value ( MNGN) .011 RUSLE Project, TX Galveston, Citrus, Bare Ground ( T95CBCBC) USLE C Factor ( USLEC) .715 .746 .760 .698 .813 .816 .806 .785 .760 .726 .692 .590 .666 .729 .782 .824 .857 .801 .902 .901 .885 .842 .786 .742 .699 .697 .712 .574 .623 .673 RUSLE Project, TX Galveston, Onion, Bare Ground ( T95ONONC)

Soil Parameters Total Soil Depth ( CORED) 180 cm http:// soils. usda. gov/ ( 71 inches)

Number of Horizons ( NHORIZ) 4 ( top HORIZN split in 2) NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/) Horizon Thickness ( THKNS) 10 cm ( HORIZN = 1) 18 cm ( HORIZN = 2) 61 cm ( HORIZN = 3) 91 cm ( HORIZN = 4) Bulk Density ( BD) 1.45g cm 3 ( HORIZN = 1) 1.45g cm 3 ( HORIZN = 2) 1.40 g cm 3 ( HORIZN = 3) 1.55 g cm 3 ( HORIZN = 4) NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/)

Initial Water Content ( THETO) 0.39 cm3 H20 cm3 soil ( HORIZN = 1 4) Field Capacity values, PRZM Scenario Guidance ( 2004) Section II. D. 6  Page 58 of 120 Compartment Thickness ( DPN) 0.1 cm ( HORIZN = 1) 1 cm ( HORIZN = 2) 1 cm ( HORIZN = 3) 1 cm ( HORIZN = 4) PRZM Scenario Guidance ( 2004)

Field Capacity ( THEFC) 0.39 cm3 H20 cm3 soil GLEAMS Table H 3 ( 1990)

Wilting Point ( THEWP) 0.28 cm3 H20 cm3 soil GLEAMS Table H 3 ( 1990) Organic Carbon Content ( OC) 1.2% ( HORIZN = 1) 1.2% ( HORIZN = 2) 0.9% ( HORIZN = 3) 0.45% ( HORIZN = 4) NRCS Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/); Adjusted using the relationship % OC = 0.6 x % Organic Matter ( Doucette 2000)

5. South Texas Corn ( STXcornCRA)