The Yakima River runs east for over 180 miles from the Cascade Range to the Columbia River at Richland, Washington. Information on the river is available from a variety of sources for the upper section above the Roza Dam. We found almost no information other than flow rates for the remaining 128 miles nor did we find any other trip reports.
The trip took five full days and our daily distance varied from 44 miles to 12 miles. Sections of the river are easy, most are intermediate, and at least one section is advanced and dangerous even though it contains nothing greater than class II rapids. Road access is non-existent to many stretches of the river.
There are six dams that must be portaged, Roza, Wapato, Sunnyside, Prosser, Chandler, and Horn Rapids. The Yakima is a highly managed river with large irrigation draws and returns. Even so, most of the river has a wild and natural appearance. The report is only valid for the given flow rates, which can fluctuate substantially. Some sections will become exceedingly dangerous or shallow with higher or lower flows.
Day 1: May24 - Ringer Road to Yakima - 37 miles
Above Roza Dam the route is safe and well known. Research this elsewhere. The portage at Roza is on river right just before the warning sign. It is 250 yards and obvious. Below Roza, the river is swift but wide and open with fast ripples, but no real rapids until exiting the Yakima Canyon near Selah, Washington. Here, some quick maneuvering is required in swift current with an occasional strainer or sweeper in class I water. At the city of Yakima the current and volume increased as the Naches River enters. Some strainers but in a wide river. We camped in the rough out of sight from anyone on one of the dozens of islands.
Day 2: May25 Yakima to river mile 96 - 12 miles
The Wapato Dam is just inside Union Gap east of Yakima. It is split by an island which we found easy to land on. We portaged easy 200 yards on the river returning to the right channel. Sunnyside Dam comes up next in about 4 miles. It is near Parker, Washington. The damn dam is unmarked. there is a 1/2 mile long island just above it. We spent 3 hours trying to find a portage. River left is easiest to exit, but there is no legal access back to the river for at least a mile and probably several more. River right has swift current and landing was difficult. We found the brush impenetrable within 200 yards of the dam until we found a drainage ditch while scouting from the island. Since you cannot see this opening from the water, forget about it. Prepare to portage from at least 1/2 mile upstream on river right. That is what I will do if I do this again. Below the dam, the river becomes braided with hundreds of rootballs, strainers and sweepers combined with blind riverbends and swift current. We scouted and then lined and waded dozens of these corners and managed to get flipped once when I misread a corner. It took 4 hours to cover 7 miles. There are few road accesses and this section of the river has a very remote wilderness feel and severity even though the sound of I-82 can be heard in the distance. We had an excellent camp on a gravel bar. We saw hundreds of white pelicans in this stretch of river. It was a very beautiful stretch of water.
Day 3: May26 - mile 96 to mile 62
The scouting, lining and wading continued to a few miles past the town of Granger, where we stopped to get drinking water. The water is beginner level after Granger EXCEPT for the first few meanders which require scouting. Irrigation return requires finding potable water. Below Granger, the river opens up into an eastern Washington combination of scrubland and farmland. Camping is legal on the state's Sunnyside Refuge, which is river left from about mile 71 to mile 60. We camped in a nicer farm pasture on river right, out of sight from the farm house. There's no easy road access out here anyway.
Day 4: May27 - mile 62 to Horn Rapids County Park - 44 miles
Easy paddle with only one set of fast ripples to Prosser, Washington. We portaged 3/4 mile through town from the boat ramp to the downriver side of the Prosser Dam. Here the river changes as the rounded cobbles of the upper river give way to the large basalt boulders of the channeled scablands. We were lucky to have a few inches of water covering almost all of the rocks. For a dozen miles or so after Prosser, there are sections of class I and class II water, some of which we lined or waded because of blind riverbends in fast current. One of these rapids became a class III at the bottom. The rapids were generally safe but did require lateral maneuvering in swift current. The rest of the day was intermediate paddling with some occasional strong eddies. We camped in the campground at Horn Rapids, which is, unfortunately, a half mile from the river.
Day 5: Horn Rapids to the Columbia River - 19 miles
Horn Rapids Dam is easily portaged on river left by pulling out above the warning sign and crossing the left irrigation canal on a foot bridge that leads to Native American fishing platforms. At the days flow rates we had nothing more than ripples in fast current to contend with until reaching the Columbia River.
16 foot Old Town Penobscot
Start at Ringer Road access near Ellensburg, Washington. It is not far from I90-I82 and not at all difficult to locate.
Earth Google and USGS topographic maps