Alley Creek - the main stem of the preserve

I hope to get a couple of more field days in over the summer but considering the heat, humidity and our national bird - the mosquito, maybe I need to spend a bit more time writing about the ‘parts’ of the preserve. As with any great landscape this preserve has a multitude of component ‘parts’. The parts (landscape features) create a variety of habitat potentials in close proximity to one another. First and foremost this preserve sits in a great glacial valley. It sits between two relatively high and flat plateaus to the east and west and is bounded by relatively steep valley walls. The flat bottom of the valley was at one time filled, wall to wall, with extensive marshes all of which were drained by the central ‘tidal creek’ -Alley Creek.

The 20th century was not kind to this valley. Large areas of marsh were lost to heavy landfilling and the area was dissected by Northern Blvd. the Long Island Expressway the cross Island Parkway and the Long Island Railroad. Urban development sprawled across the plateaus and crowded to the edge of the marsh filled valley. All of these events are stories for another post because I right now I want to focus on the component parts that still remain. The greatest of these remaining landscape features is the ‘main stem’ of the whole preserve -Alley Creek.

Alley Creek is a ‘tidal creek’ or more correctly a ‘tidal estuary’. About 3500 feet of Alley Creek is within the preserve area but it continues another 3000 feet to the north where it empties into the other gem of this valley -Little Neck Bay. Anyone who is interested in what this actually looks like can get a great overview of this area using Google Earth.

The axis of Alley Creek physically bisects the preserve setting up an east and west bank. Freshwater from a multitude of sources flow into the head of the creek in the southern part of the preserve and make its way north until they encounter the tidal waters of Little Neck Bay. This sets up the intimate and complex mixing of fresh and salt water creating the classical ‘brackish’ water condition which defines our idea of ‘estuary’.

The tidal range in Little Neck Bay averages more than 7 feet (8.3 feet when the moon is full) and is one of the largest ranges from Massachusetts to Georgia on the east coast of the US). Each rising tide sends water into the wide mouth of Alley Creek and forces it upstream overwhelming the freshwater inflows for a few hours; then, on the outgoing (falling or ebb) tide, all this water (now well mixed) is released and rushes out into Little Neck Bay. Never missing a beat, twice each day, the tidal creek fills and empties creating a ‘pulsing exchange of water’. This is a wonderful effect and prevents any contaminants from accumulating to harmful levels.

The banks of the estuary are also heavily vegetated with high and low salt marshes and below the vegetation lines are extensive tidal mudflats. Technically, Alley Creek is a tidally dominated, partially stratified, semi-diurnal estuary that is tributary to the much larger estuaries of Little Neck Bay and Long Island Sound. That’s the technical view.

To those of us who love it and who paddle its waters at high tide and to the thousands of creatures that come and go and make it their home, Alley Creek is the ‘main stem’.

It is the connective tissue that defines and holds this great valley together.