The highest water in 14 years has forced Marion Reservoir to close 77 campsites.

The entire Cottonwood Point North campground, with 46 campsites, was closed after floodwaters washed out a culvert on a road to the campground. Another 15 campsites at Cottonwood Point and 16 at Hillsboro Cove were closed because they were entirely or partially underwater because of high water in the reservoir.

Heavy rains have filled nearly half of Marion Reservoir’s emergency floodwater capacity.

Swelled even after the campgrounds closed by 1.75 inches of rain Friday and 1.79 inches Monday morning, the reservoir stood at 4.27 feet into its 8-foot flood pool at 7 p.m. Monday. It has been this full only twice in the past two decades, most recently 14 years ago.

• April 11, 1995 — when it peaked at 5.58 feet into its flood pool.
• Sept. 9, 1998 — 5.07 feet into flood pool.

At its current level, the flood pool is capable of holding 3.01 inches of additional rainfall — considerably less than what has fallen since Friday — across the reservoir's 200-square-mile drainage area.

The reservoir was at its lowest level in 20 years this past Dec. 14, when it was 3.61 feet below the start of its flood pool. Since Dec. 14, the reservoir has risen 7.88 feet, according to analysis of Corps of Engineers data. In sheer volume, it has gone from holding 58,977 acre-feet of water (19.2 million gallons) then to 110,587 acre-feet (36.0 million gallons) now — virtually doubling in size.

According to park ranger Neal Whitaker, who worked at the reservoir at the time, the highest on record was in July 1993, when the reservoir's flood pool filled. The lowest occurred 10 months before, when it was 16 feet lower.