The environment is constantly in the news these days. Most of my science students at the Cooperative High School have heard about acid rain, ozone layer depletion, and the greenhouse effect, but none of them has really experienced any of these global phenomena, much less conducted experiments on them. High school students have little notion of how environmental scientists operate in the field, how they gather samples, how they use instruments, and how they derive their findings.
This unit proposes narrowing the scope of student environmental investigation to one small stream in New Haven, namely the Mill River. This outdoor laboratory will enable my students to be real scientists. They will be able to take the tests that they have learned in the school lab, such as dissolved oxygen, pH, and conductivity, and run them on the Mill River waters. Testing will take place throughout the year and at various locations. By the end students should have a good idea of what is happening in the Mill River based on their own hands-on activities. Once they understand local conditions, they will be much more able to extrapolate their findings to global phenomena.
Another aim of this unit, besides training high school students in the techniques of environmental science, is to have them appreciate the local nature in New Haven. Too often, city students are afraid of “wilderness,” but if they are up to their knees (in boots) in the Mill River, collecting specimens, they probably will learn to enjoy their surroundings.
The next step after appreciation is activism. If the Mill River turns out to be polluted, is there anything that students can do to change the situation? At the very least they can educate themselves about the causes of the pollution. After that they should learn about Clean Water legislation and the role of the Department of Environmental Protection.
The wonderful thing about starting with a very specific project, such as surveying the Mill River, is that it will lead to all sorts of other interests, such as politics, law, history, and art. The direction taken can be determined by the students as well as the teacher. The part of the Mill River that we will study, both because it is the most interesting and also the most accessible, lies between the dam at the Eli Whitney Museum site and the tide water located under Interstate 91 where it crosses State Street. The total length of river between these two points is no more than 1.5 miles.
Students need to know that this stretch of the Mill River has had a most interesting history. Originally, before John Davenport and Theophilus Eaton and their band of Puritan settlers arrived, there was a Quinnipiac Indian camp or village where the present-day Ranger station is located (at the intersection of Orange and Cold Spring Streets). Many artifacts have been found in this area: arrowheads, chisels, and knife blades among others. There was no dam on Lake Whitney then, of course, and the Mill River was tidal along much of its length. Salt marshes of Spartina grass were washed by nutrient brackish waters twice a day, resulting in abundant ousters, crabs, and fish. In addition to these excellent food sources, the Indian tribes also had access to fresh water springs at the base of East Rock.
With the advent of the settlers. things began to change. The original Quinnipiac occupants were driven out and a low dam was built in 1640 (at the location of the present dam) by Sergeant William Fowler in order to power a grist mill. This mill burned and was rebuilt in 1665 by William Bradley and Christopher Todd. However, since the dam was quite low (no more than six feet) there was sometimes not enough water power during a drought to grind the corn. The huge mill stones from this grist mill can still be seen leaning against the present day dam on Whitney Avenue.
The next name that arises in connection with the dam on the Mill River is that of Eli Whitney. In 1798 he purchased the old Todd Mill with all the land around in order to build a factory to manufacture muskets for the government. Instead of using artisans to construct each individual musket from scratch, he proposed using water- powered specialized tools that would make interchangeable parts that could then be fitted together by unskilled help. The so-called Whitney Mill area must have been a beehive of industrial activity: rushing water, turning machines,. forges,. barges bringing materials up the Mill River, and wagons loaded with charcoal rumbling alone the east side of the river. Interestingly enough, the wooden dam that provided all this power was still only six feet high.
Even as late as 1854, the citizens of New Haven were still dependent on wells and springs for their drinking water: there was no public water supply. Fires were a real hazard. Since there were no fire hydrants, fire fighters had to form bucket brigades from the nearest well. Often the buildings burned to the ground. As a result of all of this, several concerned leaders saw the need to form a water company for their ever-expanding metropolis. These men decided that the Mill River would be an ideal location for a water supply and they approached Eli Whitney’s son. Eli Whitney II, who had taken over his father’s gun manufacture, with the proposal that a high dam be built on the site of the original six-foot dam. The timing was opportune: Whitney was worried about his competitor Samuel Colt in Hartford and this increased power capacity would keep him in business.
(figure available in print form)
The thirty-eight-foot dam was completed in 1861 and is essentially the one that stands there now. A large tract of land behind the dam was flooded to become the present 139-acre Lake Whitney. New Haven had its water supple and Whitney had his power supply.
Several other companies have occupied the Whitney site in the last century including the Heany Industries who made a pink industrial ceramic that could be found in great quantities in the river. Now the Eli Whitney Museum and the Whitney Water Center run by the Regional Water Authority are the two peaceful surviving tenants of this beautiful spot.
At this point a description of the present-day Mill River would be in order, as it flows from the Whitney Dam south to the tide gates under I-91, a distance of about 1.5 miles. The obvious markers on the river are the four bridges that cross it: going from north to south, the covered bridge at the Eli Whitney Museum, the footbridge in the marsh, the East Rock Road bridge, and the Orange Street bridge. The tide gates mark the southern boundary of the section of river to be studied.
The flow of Lake Whitney water over the dam is quite variable, depending on the season, rainfall, and the needs of the Regional Water Authority. Sometimes there is no flow at all, while at other times, a raging torrent pours over the dam. This clearly affects the amount of water in the Mill River below. The stream is normally quite shallow between the dam and the covered bridge and the water flows swiftly with ripples over the rocky bottom. It’s a good place to look for macroinvertebrates.
Between the covered bridge and the footbridge the stream enters East Rock Part, moving slowly between densely vegetated banks. Here one can often see great blue herons or black-crowned night herons, as well as numerous ducks. The water may be as deep as 6 to 8 feet at the footbridge and is much darker in color than by the dam. Fishing is the pastime of choice here: carp, sunfish, silversides, and even eel are commonly caught.
From the footbridge the Mill River moves slowly towards East Rock Road where a storm sewer empties under the bridge. From there it flows past a large marsh on the west bank to the Orange Street bridge. At this point the vegetation changes: much of the shore is composed of fill and Phraemites, a tall invasive reed, has taken over.
Between Orange Street and the tide gates the river seems to be more influenced by man than by natural forces. Its original meanders have been straightened out (due to highway construction in the 1960s). Phraemites lines the banks and the water looks murky. Finally the river now enclosed in a man-made channel reaches the tide gates. The ostensible reason for these sates, which were installed in the 1970s, is to prevent polluted waters from moving up into East Rock Park from the lower industrial reaches of the river and also from the New Haven Harbor. At low tide the fourteen small gates open to let the downstream flow of the river pass through. At high tide ( the tides in New Haven Harbor have a mean range of 6.2 feet) the gates are forced closed by incoming seawater. This means that the fresh water backs up on the other side of the gates and floods the marshes to a certain extent. However, the tide gates don’t function perfectly so that saline polluted water can move up into the marshes at high tide.
The Mill River between the dam and the tide gates is like a long mixing bowl: fresh water flows southward over the dam and salt water leaks northward through the gates and they probably mix somewhere around the Orange Street Bridge.