Data Disclaimer: Water level data is provided by USGS and NOAA for informational purposes only. Verify conditions on-site before any water activities.
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The Merwin access site near Ariel provides boat launch facilities on Merwin Reservoir, a 318-acre impoundment created by Merwin Dam on the North Fork Lewis River. Located on Highway SR-503 south of the dam in Cowlitz County, this site is suitable for kayakers, canoeists, and motorboats. The surrounding area offers additional amenities including camping sites, picnic areas, and day-use facilities managed by the dam operators.
**Important considerations for paddlers:** Water levels at Merwin fluctuate significantly with seasonal runoff, which can affect boat access and launch conditions—plan ahead and check current conditions before launching. The reservoir is popular with anglers targeting kokanee and tiger muskie. Paddlers heading downstream from the dam should note that the river below offers additional access points; a popular paddle route extends approximately 3.4 miles downriver toward the hatchery area, featuring shallow sections. The nearest major city access is via I-5 to State Route 503 heading east toward Ariel—allow extra time if traveling from the Portland area.