One of the quietest and most serene places in either West Windsor or Plainsboro is the aqueduct, the spot where the Millstone River enters Princeton’s Lake Carnegie. The entire boundary between West Windsor and Plainsboro runs down the middle of the Millstone, and when it reaches the aqueduct just west of Route 1, it actually becomes part of the lake.
But at that very same spot we also find the Delaware and Raritan Canal, a man-made waterway that has been there since the 1830s. It and its towpaths are part of the state-owned Delaware and Raritan Canal State Park. But the boundary between both West Windsor and Plainsboro and Princeton runs down its center.
Since the canal is a separate and independent waterway, however, its water must flow independently, without being affected by the flow of the river or the lake. Thus it is carried in a man-made wooden aqueduct where it crosses the Millstone. Today there are two parallel wooden foot bridges that run the length of the aqueduct, one on the Princeton side and one on the West Windsor-Plainsboro side.
Lake Carnegie was formed in 1906 as a gift from industrialist Andrew Carnegie to Princeton University. (At the time, Princeton President Woodrow Wilson had asked Carnegie to endow the new preceptorial teaching system he had envisioned. But Carnegie told Wilson that he had already given Princeton a lake, to which Wilson replied, “We needed bread and you gave us water.”) The lake was formed by building a dam across the Millstone River at Kingston. As the river backed up to the south it soon came to a point where it turned sharply to the east, flowing away from Princeton. This is the location of the aqueduct.
To ensure that the lake would continue in the direction of Princeton, Stony Brook, which flowed into the Millstone at that point, was dredged and widened so that the water backing up from the dam at Kingston would then follow its course and become part of the lake as it is today. North of Kingston the Millstone River is still known by that name and it still parallels the D&R Canal. But Lake Carnegie is the hybrid of two original waterways.
The aqueduct can be reached on foot by walking along the canal towpath, either from Harrison Street in Princeton or from Kingston, but it’s a long walk. By car, get on Route 1 south at the U-turn overpass north of Harrison Street and turn right at Mapleton Road as if you were going to Kingston. But only a short distance ahead is the parking lot for the aqueduct. It’s a beautiful and unspoiled place at the only spot where two townships and a town actually meet.
In recent decades, the aqueduct sometimes plays a role in local flooding. During sustained heavy rains in the area, there is little open land left to absorb most of the water. All the housing and paved roads with their storm sewers mean that the water flow becomes concentrated in local natural waterways — the rivers and streams. It can’t go anywhere else, since there is very little “ground” left for it to soak into. As a result much of the water from a large portion of the township ends up in the Millstone River.
When that water reaches the aqueduct, which has a fixed opening under the canal, it backs up and causes the Millstone to overflow its banks as far upstream as it will. The only way to relieve this effect would be to enlarge the opening under the aqueduct, but with the lake already overflowing anyway — because of increased runoff on the Princeton side — that wouldn’t really help.
A similar problem exists where the Millstone and Big Bear Brook flow under the railroad tracks. The openings in the stone supports of the track bed were built when there was much less runoff than there is now. As a result these waterways overflow their banks well upstream, sometimes causing a number of local roads to flood. The only solution, aside from not paving so much of the land, would be to enlarge the openings under the tracks. That’s not likely to happen.
