Thursday, January 30, 2020

Hatfield Swamp

The Hatfield Swamp is a place I often pass in my local travels. "Swamp" is not a word that cries out for you to plan a visit, so let's more accurately and kindly say that this is a freshwater wetland area.

It forms what is sometimes referred to as the "second bank" of the Passaic River at the border area between Morris and Essex counties.

The area of Hatfield Swamp is approximately 2,500 acres (10 km2), located in northern New Jersey at Latitude 40.85 N and Longitude 74.32 W.

The Swamp is part of West Essex Park and there are trails for public hiking. The Essex County Chapter of the Sierra Club and the New Jersey Audubon Society lead trips throughout the swamp in all seasons. A good starting place to explore and get information is the Essex County Environmental Center.

At the western end of the swamp, the Whippany River connects to the Rockaway River. The Rockaway River then travels a short distance into the center of the swamp where it flows into the Passaic River.

After heavy rain and if there is spring snowmelt, Hatfield Swamp floods since three rivers join here.

For animal observation, the area isn't always conducive due to the flooding. Deer, raccoons, possums, skunks and fox all live in the area (West Essex Park) but generally in the less swampy edges the swamp itself where there is higher and drier ground. We might expect to find muskrats there but the flooding would fill their bank dens with water and the area is also not conducive to plant foods that muskrats favor.

In autumn, waterfowl passing through the area rest in the swamp before proceeding south.

This wetlands area is not a place for some tree species (mostly hardwoods), but you will find various oaks, maples, sweet gum, and elm trees. (Find out more about plants found here)

Unfortunately, the three rivers that meet here were all once highly polluted. Things are better today but pollutants that remain in the soil and water have affected flora and fauna. The fish that are most likely found in the Rockaway River and Whippany River are carp and catfish.

Some history: Cornelius Hetfield owned and operated a mill at some point here before the American Revolution. Hetfield was a Loyalist during the Revolution, so his property was eventually confiscated. It was later purchased by Cyrus Crane. It stayed in the Crane family into the 1960s. The mill was dismantled and moved to Allaire State Park in Monmouth County and the swamp area of the park reverted to a slightly modernized Hatfield Swamp.

But let's go way back in Hatfield geologic time. It was the late-Triassic/early-Jurassic and when the North American plate separated from the African plate and created a rift valley. Today we refer to that rift as the Newark Basin. This valley changed over the next few millions of years, the valley faulted, tilted, and eroded and eventually the basalt layers formed ridges.  Then the Wisconsin Glacier ice sheet during the last ice age advances and plugs the gap with its glacial rubble. The glacier melts and the water pools up behind the ridges. The ridges are our Watchung Mountains and the pooled water forms Glacial Lake Passaic. Go forward thousands of years and the lake drains leaving behind swamps. The big one is our Great Swamp which drains from that Passaic River and flows through a gap in ridges passing through Hatfield Swamp.

If you want to visit, an easy starting place is the Essex County Environmental Center, which is in West Essex Park.  This site (download small map) was once a tavern and stagecoach stop, and the nearby bridge over the Passaic River is where Morris County’s historic Patriots Path connects with the Lenape Trail in Essex County.

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