APPENDIX A: BIG CREEK TMDL "CROSS-WALK" 



WATERSHED RESTORATION PLAN for Big Creek, North Fork of the Flathead River 



Water body Name: 



Big Creek 



Montana ID # MT76Q(X)2_ 



Impaired Beneficial Uses: 



Watenhed: 



North Forte Flathead 

 (HUC !70l()2()6) 



Probable Cause(s): 



Key TMDL Elements 



Condition Assessment and Problem 

 Description 



Cross-walk 



Summary 



An Environmental Analysis at the Watershed Scale was conducted. This constitutes i 

 veiy thorough analysis of the existing conditions, impairments, causes, and sources. 



Uses/Pollutants Addressed 



This document addresses cold water fisheries and aquatic life partial use support 

 conditions associated with sediment and habitat related impairment causes. 



Applicable Water Quality Standards 



See Section B- 

 1 



Big Creek is classified as B- 1 . Narrative standards as.sociated with beneficial uses 

 supported by a B-1 classification as well as narrative standards associated with 

 sediment are both addressed. 



Water Quality Standards Target or Endpoint 



The targets are: 



1) < 30% instream fine sediment This endpoint links sediment loading/transport 

 to the cold water fishery and aquatic life beneficial uses. 



2) The erosion rate of monitored impaired reaches are not significantly greater than 

 1 25% of the erosion rate of the monitored reference reaches, ba.sed on a 

 statistically valid comparison. 



3) The successful revegetation and/or protection of at least 75% of the identified 

 sediment sources. 



TMDL - Reduction Target 



See Table 6 & 

 Figure 8 



The TMDL is expressed as estimated percent reductions in erosion or sediment 

 production for six categories of proposed restoration treatments, of which it is 

 estimated that 75% or less of the total load reductions would be needed to meet the 

 water quality targets and obtain full beneficial use support Monitoring will be 

 implemented to ensure that targets are achieved via performance of a sufficient level 

 of proposed restoration worlt. 



Significant Sources 



See Section 

 B.3.3 



All significant sources and source types are identified and discussed. There are not 

 any point sources or associated waste load allocation needs in this watershed. 



Margin of Safety 



See Section C, 

 D.2 



Percent fines target is ba.sed upon 80% of internal reference; MDEQ criteria for 

 beneficial use support is based on 75% of reference conditions 

 Given current conditions being close to meeting beneficial use support targets 

 associated with percent fines and habitat it is estimated that addressing more 

 than 75% of the total reductions in sediment loading will be more than adequate 

 to meet the TMDL targets while still allowing for existing conditions with some 

 future forest management efforts as a "future growth" component of the TMDL. 

 The monitoring plan provides for an adaptive management approach and 

 includes additional indicators of stream health via macroinvertebrate and 

 periphyton sampling. 



Seasonality 



Whole 

 document 



Sediment production data, problem definition and associated modeling all apply to 

 yearly sediment loading and erosion during high runoff periods. 



Allocation/Restoration Strategy 



See Table 6 & 

 Figure 8 



Restoration treatments are proposed for virtually all of the idenliried sources 

 potentially contribudng to impairment conditions. This provides for a performance- 

 based allocation scheme whereby it is assumed that completion of proposed efforts 

 will result in conditions that are significantly better than required to ensure fiill 

 support of cold water fish and associated aquatic life in Big Creek. This then provides j 

 a margin of safety and allowance for some level of future management flexibility 

 within the drainage. This future management flexibility, or "future growth" 

 consideration includes proposed salvage logging or any other activities where it can 

 be shown that the activity will not create conditions where water quality targets could 

 not be met or the ability to meet water quality targets would be significantly delayed. 



Monitoring 



McNeil Core procedure will be employed to monitor fine sediment trends. Cross- 

 sections, Bank Erosion Index, and bank profile measurements will be used to monitor , 

 bank erosion. Effectiveness monitoring will be conducted to evaluate success of 

 implementation. This monitoring will be done yearly by the Forest Service and every 

 five years by MDEQ. The first year, the Forest Service and/or the Montana DEQ will 

 also collect samples for macroinvertebratcs and periphyton. Based on the results, 

 biological sampUng by MDEQ may continue yearly. Data will be analyzed by the 

 Montana DEQ. MDEQ five-year sampling will include macroinvertebrate and 

 periphyton sampling as an additional confirmation of beneficial use support 



Section 7 Consultation 



The Big Creek Watershed is considered Core Bull Trout Habitat To initiate the 

 consultation process, this document has been submitted to the U.S.F.W.S. 

 concurrently with submittal to the USEPA. 



Public involvement 



A thirty-day public comment period is part of the document preparation process. 

 Implementation planning is an inherent part of the Flathead National Forest Plan, 

 which has undergone public review. Many of the proposed treatment actions in this 

 document would also undergo NEPA review and a.ssociated public comment NEPA 

 documentation and associated NEPA public review is accomplished through the 

 Forest Service. 



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