PERMFILE65938 - Laserfiche WebLink

Home Browse Search

i • ~x ~` za/o~ Exhibit 3. Cottonwood Mortality ~h• ~~~-~`~ The amended reclamation plan for the proposed Line Camp Pit (M-2001-001), Exhibit page 27-b states that the effect of pit dewatering, or drawdown curve will be lessened because of proximity to the Dolores river. "This should greatly reduce the impact of the drawdown on cottonwoods to the east. The impact of the trees to the south, approximately 500 feet south of the pit, will also be ~ relatively small, with the drawdown at about three feet (not counting any recharge from the river. This is within the tolerance of cottonwoods, which can accept depths to water of from essentially zero to approximately 10 feet." This statement has no scientific basis and is therefore without merit. Nonetheless, it has been accepted by the DMG. Item 17 in the Division's Rationale for Approval Recommendation (dated May 8, 2001) states: "the application indicates that neazby Cottonwood trees should not be adversely impacted by the proposed excavation and seasonal dewatering activities". There is existing empirical data indicating that drawdown of alluvial aquifers by as little as 2.5 feet can cause cottonwood mortality ( ). Additional physical evidence that pit dewatering is a direct cause of cottonwood mortality can be seen in the Dolores Valley at the recently reclaimed Twin Spruce Pit, and at the currently operational Sunnyside and Tam~ICoenig Pits, The Tam~Koenig Pit offers an extreme example, where approximately 80% of a formerly healthy old growth cottonwood woodland has died within the last yeaz, even though the edge of the woodland is located a few feet from the river channel. Refer to photographs -note that the narrow existing belt of live trees along the river pazallels the wider belt of trees bordering the pit. Given that it has been demonstrated that a 2.5 ft drawdown of alluvial aquifers can damage or kill cottonwood trees and that a drawdown of 2.79 feet at a distance of 600 feet from the pit edge is anticipated by the operator, we aze able to project a mortality zone of neazly 10 acres for the old growth woodland to the east of the pit. A much smaller area of younger woodland to the south would also be impacted. This constitutes significant environmental damage. A map of these zones is provided on the following page. Refer to the Application for Permit by Four States Aggregates, Exhibit Page 27, 27-A, and 27-B for projected drawdown data.