The proposed indicators for assessment of a improvement in water quality trends are the following: 



D The desired condition for cold water fishery habitat, is for interstitial fine sediments not to be a limiting 

 factor to fish reproduction and survival in Big Creek. The key indicator for this objective would be the 

 amount of interstitial fine sediments occurring in the fish spawning habitat, as measured using the 

 McNeil Core methodology. 



D The desired condition for surface flow in Big Creek watershed, Is for stream channels to be in or 

 approaching equilibrium; i.e., have minimal channel erosion or sediment deposition. The key 

 indicator for this objective would be to have the same amount of streambank erosion occurring within 

 the impaired sensitive reaches, as occurs in similar non-impaired reaches upstream and downstream. 

 This objective can be monitored using channel cross-sections and bank erosion profile 

 measurements (using bank erosion pins per Rosgen technique). 



D The desired condition for the upland (ground surface between stream channels) would be to have a 

 vegetation cover (grass, forbs, and brush) or to have a rock surface armoring, thereby not being a 

 sediment sources. The key indicator for this objective would be the revegetation and/or amnoring of 

 the identified sediment sources. 



B.3.3 - Nonpoint Pollution Source Inventory and the Proposed Restoration Activities 



The following Is a short narrative description of the current upland and instream sediment sources In 

 the Big Creek, along with proposed actions that are meant to decrease the sediment load, increase 

 water dispersion and infiltration. 



Situation - 1 Streambank Erosion: The mid to lower reaches of the mainstem of Big Creek flows 

 through glaclal-fluvlal deposits, in which the stream has downcut in excess of 100 feet since the retreat 

 of the glaciers (10-12,000 years before present). This downcutting of the stream has resulted in an 

 abandoned Pleistocene age stream terrace, with a very steep (60-80% slope) terrace escarpment 

 leading down to the current stream terrace and floodplaln. Some place along this escarpment the 

 stream comes into contact with it during normal spring runoff or other peak flow events. During high 

 flow periods, the toeslopes of these exposed soil banks are eroded by the flowing stream putting 

 significant amounts of sediment into the stream. Streambank erosion in excess of one foot has been 

 observed by the author during a high flow event on these types of escarpments. The erosion of these 

 terrace escarpments is a natural process. However, the additional water flow during peak flow events 

 caused by logging and road construction, causes the stream to be In contact with these sediment 

 sources more often and for a longer duration than during pre-management times. At the same time, 

 the steep escarpment banks have large areas of unvegetated eroding soil. Refer to photograph - 7 for 

 an example of an eroding stream terrace. 



There are seven areas along the mainstream of Big Creek, where the stream is impinging upon these 

 escarpments causing a major sediment source. These sites will be examined carefully to see if 

 instream structures such as vortex-weirs, rock barbs, or tree stump armoring would help the situation 

 and can be logistically installed with the limited access to the stream. This examination needs to be 

 done in concert with the Montana Department of Fish, Wildlife and Parks, along with the U.S. Fish and 

 Wildlife Service. Once the eroding bank Is armored then there will be an attempt to establish 

 vegetation (shrubs) on the toes of the eroding slump banks, to trap the eroded soils from the steep 

 escarpment face before It reaches the stream. During the 2000 and 2001 field season there were 

 hundreds of shrubs planted on toes of five of these slide areas in an attempt to establish vegetation and 

 reduce erosion. 



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