floating four-leaf clover. The plants from Lake Whitney and Bantam Lake are the original stock from which all water shamrocks in the United States originate. Because the Mill River is a tidal river, there is an influx of salt water twice a day with the tidal changes. The seawater on the surface of the river tends to sink as lighter fresh water rises, and mixing takes place from the surface to the bottom of the river. This is known as tidal overmixing. The river water flows seaward on a shallow surface over an upstream movement of seawater. An unusual variety of vegetation grows within the confines of the fresh and salt water mix. We find a salt content in the river up to the footbridge crossing the Mill River. Here we begin to find cattails growing. These plants need less than 10% salt in the water source in order to survive. The plant material needs to be as hardy as the aquatic animal life that thrives in this fresh and salt water mix.
There is more life in a healthy wetland than there is in almost any other kind of habitat. A healthy wetland can support huge numbers of insects, fish, birds, and other animals. East Rock Park is on a major bird migration route bringing over 200 species of birds through, many of which are rarely seen elsewhere in the state. These birds converge on the wetlands on the way to their summer or winter homes to “refuel” on the rich food supply found in marshes. The spring migration of over twenty species of warblers through the park bring bird watchers from all over Connecticut. Throughout the winter, black ducks and pied-billed grebes winter on the river and woodpeckers, chickadees, brown creepers, and nuthatches, to name a few, live among the bare tree trunks.
Wetlands are vital nurseries for many species. Young fish, crab, and other creatures spend their earliest days in wetlands protected before moving out into the open waters. Wetlands also give protection to many endangered species. About 35 percent of all of the animals and plants listed as threatened or endangered in the U.S. either live in wetlands or depend on them in some way. Mammals, reptiles, and amphibians thrive in the flood plain marshes of the Mill River. Racoon, skunks, and oppossum live year round in the park. Muskrat, snakes, snapping turtles, and salamanders live in the river or along the river banks in the marshes. Red fox, bats,and flying squirrel are the more elusive residents of the park. The type of fish depend of the salinity of the water. Upriver where the water is fresh, sticklebacks, goldfish, carp, pumpkin seeds, banded killifish, and more recently, large mouthed bass thrive. Farther downstream towards the mouth of the river are found, among other species, mummichop which can stand the pollution and saltiness of the river.
Industrial waste, sewage, and thermal pollution has taken its toll on the Mill River. Just above State Street are old tide gates reaching across the river which have the enormous job of keeping polluted water from flowing upstream during the influx of high tide. There have been hundeds of acres of marsh land around the Mill River and New Haven Harbor that have been destroyed, drained and filled in for houses , roads, and other developments. Plans are in place to clean up the Mill River and to further protect this beautiful resource. Funding and time seem to be the continuing factors in actualizing these plans. Right now the city of New Haven is in the process of installing a sewage separation system in parts of the city. This will mean cleaner water in the surrounding rivers and in Long Island Sound. Heavy rains often force sewage to overflow into the Sound and into local rivers. With this new system fresh storm water will be routed into the Sound while human waste will be enclosed and routed to a sewage treatment plant.
East Rock Park
(figure available in print form)
To understand the geology of Lighthouse Point in relation to the rest of New Haven we have to go back about 250 million years. At that time there was a melding of continents, a collision which formed a single land mass. This coll