Directions to the TH are accurate in Dan nelson's "Desert Hikes Washington". Billy Clapp Lake is more than 3 miles long and receives its water from the main canal from Banks Lake. The water is dumped into Billy Clapp Lake via Summer Falls where water is released only in the spring and summer to meet irrigation needs. The lake is beautiful with many basalt cliffs lining the lake. Sadly the first 1/4 mile is littered with trash. We carried out a 1/2 gallon spiced wine bottle, a pink air mattress, and a gatorade bottle on our return to the TH. All were within 50 yards of the TH. We saw a loon at our lunch spot. Phlox, Phacelia, larkspur, balsamroot, wallflower, and white lupine were some of the flowers seen.