This project intended to link nutrient loads with land-use and grazing practices in the 

 basin. Although the peak nitrogen levels measured at Stations 5-9 coincide with 

 polygons exhibiting severely impaired riparian areas, it doesn't appear that grazing is the 

 predominant factor influencing nutrients in this reach. As discussed above, high levels of 

 nitrogen in the area of Dutchman reservoir appear to be influenced more by additions of 

 flow from numerous potential sources than by the presence of cattle. However, it is 

 likely that impairment of the riparian wetlands by grazing and flow manipulation may 

 reduce nutrient trapping and uptake by riparian vegetation. 



Although this discussion does not intend to critique proposed restoration work, several 

 comments regarding its potential success should be noted. First of all, despite severe 

 impacts from grazing on woody vegetation (and in some areas the complete absence of 

 mature woody species), shrub regeneration was high for nearly all the polygons 

 inventoried. This suggests a strong potential for relatively rapid re-establishment of 

 mature woody vegetation through proposed management that would reduce grazing 

 intensity and duration. Allowing mature vegetation to develop is likely to confer 

 multiple benefits to water quality, such as moderating temperature by shading, increasing 

 bank stability, and trapping sediments and nutrients. Periodic inventories, both for 

 riparian health and water quality, may yield a closer relationship between land 

 management and parameters such as nutrients, temperature and sediment. In this sense, 

 the main value of riparian inventories on Lost Creek may lie in their continued 

 application as a monitoring and adaptive management tool, which will be discussed 

 further in the section on TMDL recommendations. 



Recommendations for TMDL Development on Lost Creek 



This discussion is not intended to represent an exhaustive set of TMDL 

 recommendations, since much information is still unknown concerning the relationship 

 between land-use and water quality in Lost Creek, particularly with respect to possible 

 groundwater loads. Therefore, this discussion will evaluate the components of TMDL 

 development for sediments and nutrients utilizing what information currently exists for 

 TMDL decisions. In addition, specific recommendations for additional information and 

 monitoring are discussed. The following questions will be addressed: 



1 ) Are there sufficient credible data for beneficial use determinations? 



2) What, if any, beneficial uses are impaired? 



3) What are the causes and sources for impairment? 



4) What are reasonable targets for water quality? 



5) What actions are planned to address the problem? 



6) What monitoring should be required? 



Are there sufficient credible data for beneficial use determinations? 



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