percent crown removed with an 

 equivalent amount of clearcut area. 

 For example, if 100 acres had 60 

 percent crown removed, EGA would be 

 approximately 50, or equivalent to a 

 60-acre clearcut. The relationship 

 between crown removal and EGA is not 

 a 1-to-l ratio, so the percent EGA is 

 not always the same as the percent 

 canopy removal. As live trees are 

 removed, the water these trees would 

 have evaporated and transpired either 

 saturates the soil or is translated 

 to runoff. This method also 

 calculates the recovery of these 

 increases as new trees revegetate the 

 site and move toward preharvest water 

 use . 



In order to evaluate the watershed 

 risk of the potential water-yield 

 increase effectively, a threshold of 

 concern must be established. In 

 order to determine a threshold of 

 concern, acceptable risk level, 

 resource value, and watershed 

 sensitivity are evaluated according 

 to Young (1989) . The watershed 

 sensitivity is evaluated using 

 qualitative assessments, as well as 

 using procedures outlined in Forest 

 Hydrology Part II (1976) . The 

 stability of a stream channel is an 

 important indicator of where a 

 threshold of concern should be set. 

 As water yields increase as a result 

 of canopy removal, the amount of 

 water flowing in a creek gradually 

 increases . When these increases 

 reach a certain level, the bed and • 

 banks may begin to erode . The more 

 stable streams will be able to handle 

 larger increases in water yield 

 before they begin to erode, while 

 less stable streams will experience 

 erosion at more moderate water-yield 

 increases . 



ANALYSIS AREA 



SEDIMENT DELIVERY 



The analysis area for sediment 

 delivery is the Dog Meadow Timber 

 Sale Project area and the proposed 

 haul routes. Dog Creek is a 9,459- 

 acre watershed that includes Dog 



Lake. Dog Greek is a perennial 

 third-order tributary to Stillwater 

 River. Analysis will cover all 

 stream segments within the watershed 

 and all roads and upland sites that 

 may contribute sediment to Dog Greek. 



WATER YIELD 



The analysis area for water yield is 

 the Dog Greek watershed. Dog Creek 

 is a 9,459-acre, third-order 

 watershed. Dog Lake is a 99-acre 

 lake that is fed and drained by Dog 

 Creek. The Dog Creek watershed also 

 contains dozens of wetlands and 

 beaver dam complexes . These wetlands 

 and Dog Lake serve to moderate and 

 stabilize the effect of water yield 

 by releasing water more slowly and 

 evenly than incoming flows. 



EXISTING CONDITIONS 



REGULATORY FRAMEWORK 



Montana Surface Water-Quality 

 Standards 



According to Administrative Rules of 

 Montana (ARM) 17.30.608 (1), the 

 Stillwater River drainage, including 

 Dog Creek, is classified as B-1. 

 Among other criteria for B-1 waters, 

 no increases are allowed above 

 naturally occurring levels of 

 sediment, and minimal increases over 

 natural turbidity. "Naturally 

 occurring, " as defined by ARM 

 17 . 30 . 602 (17), includes conditions 

 or materials present during runoff 

 from developed land where all 

 reasonable land, soil, and water 

 conservation practices (commonly 

 called BMPs) have been applied. 

 Reasonable practices include methods, 

 measures, or practices that protect 

 present and reasonably anticipated 

 beneficial uses. These practices 

 include, but are not limited to, 

 structural and nonstructural controls 

 and operation and maintenance 

 procedures . Appropriate BMPs may be 

 applied before, during, or after 

 completion of potentially impactive 

 activities . 



Designated beneficial water uses 

 within the project area include 



Page D-2 



Dog/Meadow Timber Sale Project Draft EA 



