PERMFILE108645 - Laserfiche WebLink

Home Browse Search

• The willows are short (not exceeding 4 feet) and are not continuous, but tend to grow only in the areas of greatest water availability (such as at the confluence of drainages). This region of subirrigation is very local, however, as no willows are seen growing downstream anywhere else in the North Fork of Bolton Draw. Hence the rationale for saying that the perched alluvial aquifer is isolated from the main water table aquifer downstream near well 2. An examination of exploration holes in the vicinity of the North Fork of Bolton Draw indicates that the depth to water within the region of unnamed alluvium is around five feet. In places it may be less than that. However, upstream of this alluvium in the vicinity of Wells SA, SB and SC, the depth to groundwater increases quickly. Well SC, which was spudded directly into consolidated rock did not encounter groundwater until 25 feet. Downstream from the alluvium (essentially south of the M&T access road) the level of • groundwater again drops to around 9 feet as indicated by drill hole SM-4. This water level probably stays at about this level below the ground surface from this point downstream to the vicinity of Well 2 where the level of groundwater over the past year has varied from never higher than 6-8 feet below the ground through that time period. For this reason, that is, because the groundwater table through time at Well 2 has never been higher than the adjacent channel of the North Fork of Bolton Draw, Wyoming Fuel Company determines the drainage course from this point upstream to be an ephermal drainage. By definition, an ephemeral stream flows only in response to pre- cipitation events (as does the North Fork of Bolton Draw), and never has a groundwater table which is at or above the channel bottom (as is proven by We11 2 through one year's monitoring). n U -113-