For all intents and purposes, Summer Falls is a man-made waterfall. Technically any water draining down Arbuckle Draw and Trail Lake Coulee would have flowed over the falls, but so little precipitation falls in this area it would have been for a matter of days, if not hours. With the construction of the Columbia Basin Reclamation Project a series of canals were built to divert water to various parts of the Columbia Plateau for irrigation. The primary canal emanating from Banks Lake was routed over the cliffs at the head of Trail Lake Coulee, forming Summer Falls. The full volume of the Canal was initially allowed to flow over the falls, but some time in the mid 1980s a hydroelectric station went online adjacent to the falls, diverting almost the entire flow away from the falls. When enough water is being pumped into Banks Lake, the falls should be flowing, but the only time when the full force of the original falls will be evident is if the generating station needs to go offline for maintenance. The site was formerly administered by the state, but due to budget constraints was turned over to the Bureau or Reclamation in 2003.
- Summer Falls is the Official name of this waterfall.
Summer Falls was named initially because it only flowed during the summer when the irrigation diversion system was actively being used. However the meaning of the name doesn't necessarily apply any longer.
Summer Falls is accessed from Highway 2 in Coulee City in central Eastern Washington. Crossing the Dry Falls Dam along Highway 2, turn right at the sign pointing to Coulee City (N 4th St). Drive 4 blocks and turn left on W. Walnut Street, following signs for Summer Falls, then turn right on McEntee Street, again watching for signs to Summer Falls. McEntee turns into Pinto Road, follow this for 8 miles to an unmarked dirt road on the left (2 1/2 miles after crossing the North Main Canal - if you start driving up a long hill, you've gone too far). A sign denoting the Falls and a gate are found just down the road but are hard to see from the main road. The falls are found 1 mile further down the dirt road at the park.