Bureau of Land Management extends temporary closure at Hammer Creek due to boat ramp construction Cottonwood, Idaho – The Bureau of Land Management’s (BLM) Cottonwood Field Office has extended the current temporary closure at the Hammer Creek recreation site into mid-March to complete improvements to the boat ramp. Construction at the site began in early January and, when completed, will provide additional access for anglers and recreationists to the Lower Salmon River. The extended closure through March 22 affects the parking area and use of the boat ramp. The public is asked to avoid the area to allow contractors to work safely.