Photo by Oliver Griswold

The Potomac River, swelled with rainfall from Hurricane Sandy, has started pouring on to Georgetown Waterfront Park, dragging a thick layer of muck and debris onto the boardwalk there.

The National Weather Service reported moderate flooding of about one foot above the flood level, measured near Wisconsin Avenue at 11:54 a.m. The flood level in Georgetown is six feet.

Washington Harbour raised its flood walls earlier this week, hoping to avoid a situation like last year’s in which a rising Potomac flowed into several ground-floor restaurants, ruining their businesses. The photo above was taken from above Nick’s Riverside Grill, and visible in the rising water are many fallen tree limbs and other detritus created by Sandy’s powerful winds and rain.

Across the Potomac, Alexandria experienced a bit of flooding last night and again this morning when water gushed over the banks and coated King Street in the heart of Old Town. The Post reports the water extended as far as 200 yards beyond the usual riverbank.

As Sandy approached forecasters warned flooding caused by the giant storm could be the worst D.C. has experienced in 16 years, but the National Weather Service currently projects any flooding caused by the hurricane to remain at moderate levels (up to four feet above flood stage) at worst. The Potomac is expected to be swollen from Sandy through Friday.