APPENDIX I HERBICIDE RISK ASSESSMENT. Table 1 Chemical Risk Assessment Factors Low Resolution Risk Assessment (Rice 1990)

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1 APPENDIX I HERBICIDE RISK ASSESSMENT Method Table 1 Chemical Risk Assessment Factors Low Resolution Risk Assessment (Rice 1990) Low Resolution Risk Assessment (Montana Level 2 Recommendations) Soil Texture Clay Loam Infiltration Rate - High 4 inches/hour Infiltration Rate - Low 0.5 inches/hour Delivery and dilution Seven Day low flow 2-year return interval flow Runoff and Infiltration Half runoff, Half infiltration All runoff T= time of flow yielding chemical estimated 54,000 seconds (15 hours) 21,600 seconds (6 hours) D = delivery ratio on-site producting overland flow 5% 2% M = Maximum Probable LC50/ hours for fish species present or available NOEL, NOEC, NOAEL Median Lethal (mg/l or ppm) LC50 No Observed Effect Level NOEL No Observed Effect NOEC No Observed Adverse Effect Level NOAEL Expected Environmental (ppm) worst case situation = Direct application into standing water EEC LC50/20 for most sensitive species present Selway Bitterroot Wilderness Invasive Plants Management Project Final EIS I-1

2 TABLE 2 - Calculation of Maximum Acres to be Treated Maximum Acres to be treated per subwatershed (Rice, 1990) Low Flow - Qlow (cfs) J Worst Case Capacity (pounds) C= J*62.43*T Maximum Probable LC50/20 (ppm) M Rate (lbs/acre) R Delivery Ratio (percent) D Maximum Acres to be treated in HUC 6 A = (M * C)/( *R*D) Low Flow Calculation (Embry 1991) Annual Flow (cfs) Precipitation (inches) Area (sq. miles) Seven day low flow (cfs) QAA = (P * A)^.9641 P A Qlow = (P * A)^.9641 I-2 Selway Bitterroot Wilderness Invasive Plants Management Project Final EIS

3 Chemicals Evaluated Common Brand Name Typical Rates (lbs/acre) TABLE 3 - Herbicide Assessment Factors Median Lethal Maximum Label Rates (lbs/acre) 96 hour - LC50 (mg/l) LC50 (ppm) Lower Risk LC50/20 (ppm) NOEL or NOEC Source for LC50 or NOEL or NOEC Aminopyralid Milestone >100 5 LC50/96 hour, (technical grade) for rainbow trout from United States Office of Prevention, Pesticides Environmental Protection and Toxic Substances Agency (7501C) Pesticide Fact Sheet Chlorsulfuron Telar to 30 SERA brown trout Clopyralid Transline ( 100 mg/l), (Syracuse 1999: 20 mg/l, NOAEL fish/macros) Dicamba Banvel, Vanquish LC50 fish-trout ( syngenta) Glyphosate Rodeo Rodeo = ppm mg/l LC50 - trout, salmon, ave = 923 (syracuse 2003) Imazapic Plateau > SERA rainbow trout Imazapyr Arsenal > SERA rainbow trout Metsulfuron methly Escort (Herbicide, XP) ( Dupont) LC 50 rainbow trout Picloram Tordon ( 101, 22k) EPA, NOEC = 0.55 mg/l rainbow trout; Rice, Peak NOEC =.29 ppm 24hour Cuttroat (Syracuse 2003) 26 mg/l rainbow trout (Dow AgroSciences Sulfometuron Oust > SERA rainbow trout Triclopyr Garlon 3A (TEA) NOEC, LC50/96 hour fish (Syracuse Triclopry 4 Estera 2003) R&P ,4-D Amine 4, Weedar 64, LC50/96 hour fish (Syracuse 2001); NOEL = 10 mg/l for fish (salt & esters) Selway Bitterroot Wilderness Invasive Plants Management Project Final EIS I-3

4 TABLE 4 Subwatershed Information and Estimation of Annual and Low Flow Subbasin 6 th Field HUC Subwatershed Name Bitterroot River (sq. miles) Annual Precipitation (inches) Annual flow QAA (cfs)* Low Flow Qlow (cfs)** Sheephead Creek 12, Watchtower Creek 10, Soda Springs Creek 15, Nez Perce Fork of Bitterroot River 23, Boulder Creek 13, Trapper Creek 18, West Fork Bitterroot River (Lower) 22, Lost Horse Creek 27, South Fork Lost Horse Creek 19, Chaffin Creek 12, Tin Cup Creek 27, Rock Creek 36, Roaring Lion Creek 16, Sawtooth Creek 19, Canyon Creek 10, Blodgett Creek 18, Mill Creek/Sheafman Creek 25, Fred Burr Creek 15, Bear Creek 17, Sweathouse Creek 18, Big Creek 22, Sharroot Creek 10, Kootenai Creek 20, Bass Creek 9, Sweeney Creek 12, Larry Creek 30, One Horse Creek 9, Carlton Creek 16, South Fork Lolo Creek 24, Lolo Creek - Sheldon to Mormon 31, I-4 Selway Bitterroot Wilderness Invasive Plants Management Project Final EIS

5 Subbasin 6 th Field HUC Subwatershed Name Upper Selway Lower Selway (sq. miles) Annual Precipitation (inches) Annual flow QAA (cfs)* Low Flow Qlow (cfs)** Deep Creek 36, Selway River-Magruder Creek 22, Indian Creek 32, Selway River-Sheep Creek 15, Selway River-Bad Luck Creek 27, Upper Little Clearwater River 24, Lower Little Clearwater River 20, Upper White Cap Creek 35, Canyon Creek 27, Lower White Cap Creek 21, Upper Running Creek 24, Lower Running Creek 17, Eagle Creek 16, Selway River-Elk Creek 18, Goat Creek 18, Ditch Creek 11, Selway River-Dog Creek 27, Pettibone Creek 20, Upper Bear Creek 18, Wahoo Creek 13, Middle Bear Creek 16, Lower Cub Creek 17, Upper Cub Creek 21, Paradise Creek 18, Lower Bear Creek 9, East Fork Moose Creek Headwaters 21, Upper East Fork Moose Creek 22, Cedar Creek 16, Middle East Fork Moose Creek 30, Lower East Fork Moose Creek 29, Upper North Fork Moose Creek 17, West Moose Creek 19, Middle North Fork Moose Creek 10, Rhoda Creek 36, Selway Bitterroot Wilderness Invasive Plants Management Project Final EIS I-5

6 Subbasin 6 th Field HUC Subwatershed Name Lochsa River (sq. miles) Annual Precipitation (inches) Annual flow QAA (cfs)* Low Flow Qlow (cfs)** Lower North Fork Moose Creek 17, Lower Moose Creek 11, Selway River-Meeker Creek 28, Marten Creek 20, Three Links Creek 28, Mink Creek 10, Selway River-Pinchot Creek 31, Otter Creek 10, Middle Meadow Creek 33, Buck Lake Creek 20, Lower Meadow Creek 31, Gedney Creek 30, Boulder Creek 30, Spruce Creek 15, Upper Colt Killed Creek 24, Upper Big Sand Creek 17, Hidden Creek 10, Lower Big Sand Creek 24, Middle Colt Killed Creek 10, Colt Creek 16, Storm Creek 32, Upper Warm Springs Creek 13, Wind Lakes Creek 12, Lower Warm Springs Creek 19, Lake Creek 33, Lochsa River - Stanley Creek 31, Lochsa River - Bald Mountain Creek 28, Lochsa River - Bimerick Creek 34, Old Man Creek 28, Split Creek 9, * Annual Flow (cfs) = QAA = (P * A)^.9641, where P = Precipitation (inches) as weighted average for subwatershed and A = Subwatershed Area (sq. miles) (Embry 1999). **Seven day low flow (cfs) = Qlow = *QAA^ (Embry 1991). I-6 Selway Bitterroot Wilderness Invasive Plants Management Project Final EIS

7 TABLE 5 Herbicide Risk Assessment for Picloram based on P. Rice 1990 Subbasin HUC 6 Subwatershed Name (HUC 6) Low Flow Qlow (cfs) Worst Case Capacity (pounds) Maximum Probable LC50/20 (ppm) Rate (pounds/acre) Delivery Ratio (percent) Maximum Acres to be treated in HUC 6 J C= J*62.43*T T = 21,600 sec. M R D A = (M * C)/( *R*D) Sheephead Creek ,091, % Watchtower Creek ,653, % Soda Springs Creek ,835, % Boulder Creek ,667, % Trapper Creek ,796, % West Fork Bitterroot River (Lower) ,676, % Lost Horse Creek ,053, % South Fork Lost Horse Creek ,032, % Chaffin Creek ,510, % Tin Cup Creek ,926, % Rock Creek ,273, % 163 Bitterroot Forest Roaring Lion Creek ,611, % Sawtooth Creek ,642, % Canyon Creek ,890, % Blodgett Creek ,500, % Mill Creek/Sheafman Creek ,181, % Fred Burr Creek ,724, % Bear Creek ,289, % Sweathouse Creek ,442, % Big Creek ,101, % Kootenai Creek ,682, % Bass Creek ,030, % Sweeney Creek ,973, % One Horse Creek ,795, % Carlton Creek ,282, % South Fork Lolo Creek ,536, % 138 Selway Bitterroot Wilderness Invasive Plants Management Project Final EIS I-7

8 Subbasin HUC 6 Subwatershed Name (HUC 6) Low Flow Qlow (cfs) Worst Case Capacity (pounds) Maximum Probable LC50/20 (ppm) Rate (pounds/acre) Delivery Ratio (percent) Maximum Acres to be treated in HUC Deep Creek ,813, % Selwway River-Magruder Creek ,867, % Indian Creek ,466, % Selway River-Sheep Creek ,795, % Selway River-Bad Luck Creek ,489, % Upper Little Clearwater River ,482, % Lower Little Clearwater River ,176, % Upper White Cap Creek ,952, % Canyon Creek ,260, % Lower White Cap Creek ,579, % 81 Upper Selway Lower Running Creek ,418, % Eagle Creek ,251, % Selway River-Elk Creek ,263, % Goat Creek ,233, % Ditch Creek ,144, % Selway River-Dog Creek ,592, % Pettibone Creek ,320, % Upper Bear Creek ,159, % Wahoo Creek ,349, % Middle Bear Creek ,582, % Lower Cub Creek ,093, % Upper Cub Creek ,743, % Paradise Creek ,456, % 79 Lower Selway Lower Bear Creek ,605, % East Fork Moose Creek Headwaters ,712, % Upper East Fork Moose Creek ,807, % Cedar Creek ,694, % Middle East Fork Moose Creek ,983, % Lower East Fork Moose Creek ,675, % Upper North Fork Moose Creek ,016, % 87 I-8 Selway Bitterroot Wilderness Invasive Plants Management Project Final EIS

9 Subbasin HUC 6 Subwatershed Name (HUC 6) Low Flow Qlow (cfs) Worst Case Capacity (pounds) Maximum Probable LC50/20 (ppm) Rate (pounds/acre) Delivery Ratio (percent) Maximum Acres to be treated in HUC West Moose Creek ,038, % Middle North Fork Moose Creek ,350, % Rhoda Creek ,198, % Lower North Fork Moose Creek ,437, % Lower Moose Creek ,352, % Selway River-Meeker Creek ,814, % Marten Creek ,751, % Three Links Creek ,666, % Mink Creek ,225, % Selway River-Pinchot Creek ,220, % Otter Creek ,175, % Buck Lake Creek ,654, % Gedney Creek ,908, % Boulder Creek ,703, % Upper Colt Killed Creek ,618, % Upper Big Sand Creek ,192, % Hidden Creek ,103, % Lower Big Sand Creek ,602, % Middle Colt Killed Creek ,855, % 56 Lochsa River Storm Creek ,457, % Upper Warm Springs Creek ,478, % Wind Lakes Creek ,111, % Lower Warm Springs Creek ,859, % Lake Creek ,477, % Lochsa River - Bald Mountain Creek ,157, % Lochsa River - Bimerick Creek ,710, % Old Man Creek ,105, % Split Creek ,012, % 44 TOTAL 7,575 Selway Bitterroot Wilderness Invasive Plants Management Project Final EIS I-9