Once probable causes of water quality impairments are determined, ideally the 

 level of pollution reduction or habitat restoration required to restore beneficial uses can 

 be estimated to guide restoration actions. In the case of nutrients, load reductions and 

 instream targets should be based on maintaining nutrient concentrations below the level 

 that would stimulate aquatic plants to reach nuisance levels, interfering with beneficial 

 uses, and/or depleting dissolved oxygen. Again, a study of this linkage is critical to 

 developing a nutrient loading and instream targets for the Lost Creek TMDL. In the 

 event that aquatic plants are not impairing Lost creek, the nutrient target for the Lost 

 Creek TMDL should be set so as to meet the nutrient targets for the Upper Clark Fork 

 River. Establishing a target of 300 ppb TN and 20 ppb TP for Lost Creek would be a 

 reasonable step towards achieving the Clark Fork VNRP proposed 20% reduction in 

 nonpoint sources. Achieving the Clark Fork VNRP targets in Lost Creek would represent 

 a 36% reduction in nonpoint source of nitrogen to the Upper Clark Fork River mainstem. 

 In the event that summer levels below 300 ppb TN cannot be maintained at the mouth of 

 Lost Creek through reasonable land and water conservation practices then nutrient levels 

 in Lost Creek may exceed Clark Fork targets, providing Lost Creek's load to the river 

 doesn't significantly raise Clark Fork River concentrations below the mixing zone. 



Sediment targets should be set to ensure fishery impairment is not resulting from 

 increased bed load sedimentation. Based on the data from this study, TSS may not be a 

 good indicator of sediment problems since stream flow alterations in Lost Creek 

 moderate sediment in the water column. In Lost Creek, sediment targets could focus on 

 bed load sediment in combination with targets for riparian and stream habitat. At 

 present, MFWP estimates that approximately 4,000 cubic yards of sediment in excess of 

 natural background erosion are being delivered to Lost Creek each year (Reiland, pers. 

 comm.). The MFWP further estimates a reduction of 40% in delivery of sediment based 

 on reductions in eroding stream bank and lateral migration of the stream channel. Since 

 sediment loading appears to be dominated by bank instability, setting a target for 

 sediment in terms of readily measured parameters of riparian habitat and stream health is 

 perhaps the best approach. As in the case of the Deep Creek TMDL, reducing the 

 percentage of eroding banks is a justifiable "good faith" approach in an adaptive 

 management plan where numeric load allocations are substituted with effective 

 management and stream restoration (EPA, 1999b). Therefore, targets for riparian health 

 could be set to so that all polygons exhibit improvement in Lotic Inventory scores each 

 year (or management be adapted to ensure their improvement) with all polygons scoring 

 as fully functional at the end of 10-15 years. 



It should be noted that, in the absence of point sources, TMDLs are still required 

 to establish all load allocations for existing or future nonpoint sources including 

 background levels, and integrate a margin of safety (EPA, 1999a,b). While a phased 

 TMDL can establish general goals for nutrient and sediment loads, developing a load 

 allocation for the land application of Anaconda's wastewater would be an integral part of 

 the final TMDL. In order to accomplish this, several components should be added to the 

 proposed restoration (see next section). 



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