When the waters from the Ice Age Floods poured out of the Grand Coulee, they quickly filled the Quincy Basin, overtopped the low points of Evergreen and Babcock Ridges, then dropped 850 feet in less than three miles to the Columbia River, carving the spectacular recessional cataracts we know today as Crater, Potholes, and Frenchman Coulees.
Just southwest of Quincy, Potholes Coulee—like Frenchman Coulee a few miles to the south—consists of 2 cataract-lined arms or alcoves separated by a basalt rib over 350 feet high, 1000 feet wide, and a mile and half long.
Ancient Lakes, four small disconnected lakes, lie at the head of the North Alcove, and feature a waterfall plunging 160 feet into the easternmost lake. Much-larger Dusty Lake lies at the head of the South Alcove. Both arms are lined with 200 to 300-foot basalt cliffs towering above the coulee floor. The entire area is a well-known hiking destination and Dusty Lake in particular has become increasingly popular with backpackers itching to get out in the early season. There are two ways to access this area; an upper and a lower trailhead
Start out from from the parking area at the gate. Walk 1.5 miles down Quincy Lakes Road to a parking area on the right at an old metal sign marked “Dusty Lake Trail” across from the west end of Burke Lake. (note that from January 1 to September 30, this gate is open, and you can drive the road to the parking area near the Dusty Lake sign).
From the sign marked "Dusty Lake Trail", drop down the upper cataract on a trail with a handrail to the next lower bench. Follow the trail across the bench and down the middle cataract 0.5 mile to the east end of Dusty Lake. Return the way you came.
The route to Dusty Lakes from the lower trailhead follows the old 2-track along Babcock Bench as if heading for Ancient Lakes, but instead of turning off towards those lakes, continue across the mouth of the North Alcove and around the nose of the coulee rib about 1 mile to another old 2-track heading left up the South Alcove. Follow this trail up the coulee about a mile to the west end of Dusty Lake.
This end of Dusty Lake is much broader than the east end with plenty of area to explore. When you’re ready to depart, return the way you came.
WTA Pro Tip: The water in all the lakes is irrigation runoff and is not safe to drink even after filtering or boiling. Plan to carry all the water you need for the duration of you outing.