the watershed has occurred on these soils in subwatershed -03. Road density, the number of 

 stream crossings and proximity of roads to streams are also influencing this indicator in this 

 subwatershed. This indicator is functioning at unacceptable risk in subwatershed -03. 

 Subwatershed -01 has had relatively little timber harvest, contains no irrigation diversions and 

 has a low road density. This indicator is functioning appropriately. One-third of subwatershed - 

 02 is comprised of sensitive soils. Road density on these soils are low (0.7 miles/mile^). The 

 flow regime is altered in subwatershed -02 as a result of an extensive irrigation diversion system. 

 This subwatershed is functioning at risk. Most of subwatershed -04 is private land. No areas of 

 sensitive soils are known, although the road density is moderate and 30% of these roads are 

 within 300' of streamcourses. The flow regime has been altered by the presence of an extensive 

 irrigation ditch system. Based on these factors subwatershed -04 was rated as functioning at risk 

 for this indicator. 



18) Riparian Conservation Area: Substantial disturbance (roads, agricultural practices, livestock 

 production, irrigation diversion) has occurred within Riparian Habitat Conservation Areas in 

 subwatersheds -03 and -04. These subwatersheds are functioning at unacceptable risk. 

 Subwatershed -01 is mostly unimpacted by human activities (functioning appropriately). 

 Subwatershed -02 still retains a moderate similarity to natural riparian conditions, although the 

 downstream portions of Upper Willow Creek in this subwatershed are more altered. This 

 subwatershed is functioning at risk. 



19) Disturbance Regime: The Upper Willow Creek watershed has been significantly altered by 

 human activities for nearly 100 years. Evidence of human activity is minimal in subwatershed - 

 01, but increases moving downstream. The Sub-basin Review (USPS, 1998) identified the forest 

 types in the downstream subwatersheds as "high risk" for forest species/composition and 

 insect/disease due to a higher percentage of warm/dry habitats. Subwatershed -03 may be the 

 highest risk subwatershed due to the amount of sensitive soils, past human activities and the 

 vegetation risk. Subwatershed -02 also contains a substantial percentage of sensitive soils but 

 has had less human impacts, while subwatershed -04 has had the most extensive level of human 

 use but lies on stable land forms. The ratings for the subwatersheds are functioning appropriately 

 in -01 and functioning at risk in -02, -03, and -04. 



Integration of Species and Habitat Conditions 



Bull trout in the Upper Willow Creek watershed exist as only a remnant population. Eastern 

 brook trout are abundant and hybridization between these two species is documented in this 

 watershed. Westslope cutthroat trout are common in the upper portion of the watershed. Their 

 status is unknown in the lower reaches of Upper Willow Creek, although a genetically pure 

 population has been documented in a tributary (Cowan Gulch). Both rainbow and brown trout 

 have been documented in the lower reaches of Upper Willow Creek. Fish sampled in the lower 

 reaches of the stream have tested positive for whirling disease and T. tubefix worms have been 

 sampled at a number of locations throughout the watershed. 



Upper Willow Creek has been impacted by human activities for nearly a century. Past human 

 activities, primarily mining, roading, water diversions, the introduction of non-native fish, and 

 conversion of land to agricultural purposes has severely reduced the capability of this watershed 



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