Piermont Marsh - Hudson River Reserve, NY

Tidal Range

The average tidal range at the component is 3.2 feet.

River Flow

The Sparkill Creek discharges into the north end of the marsh at the component.

Geology

The west shore of Piermont Marsh is formed by part of the Palisades Ridge, a flat-topped, 150-foot high cliff and siderock formation. The cliff is Triassic diabase, a hard igneous rock between 210 and 245 million years old, underlain by Triassic sandstone and shale. Sparkill Gap, the valley of Sparkill Creek, just west of the north end of the Piermont Marsh, is the only sea level break in the Palisades Ridge.

Sediments present at the Piermont site are peat and organic silt. These deposits are at least 40 feet deep in the western part of the marsh, which has been developing for nearly 5,000 years. Soils on the shore near the site are derived from glacial till. These are shallow and acid, with deeper and richer pockets close to the marsh. A few well-defined but relatively shallow tidal creeks cut the marsh. Piermont Marsh is located at the south end of the broad and shallow Tappan Zee, and extensive shallows border the east side of the marsh.