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History of Windsor's River Life

Evolving River Names

According to ancient gravestones and historical documents, the Farmington was known as “The Rivulet” or “Little River” throughout the 1700s. In Windsor, the river was a port-of-entry for heavy trade with Liverpool, England and the West Indies until a bridge crossing the Connecticut River was constructed in Hartford in 1809. During the 19th century, the river was sometimes called the “Tunxis River” or the “Windsor Ferry River” due to a ferry located below the bridge on Rt. 159.

Shad Derby Historic Festival

The Farmington River has supplied Windsor with fish since the town’s founding in 1633. Fishing for shad in the spring has been a ritual since Native American habitation. Every May the town of Windsor celebrates Shad Derby on the town green. Originally a fishing contest, Shad Derby has expanded in recent years to a week-long full-scale community festival.
River Mills

Similar to other towns along the Farmington, mills have been situated along the river in Windsor since the early 1800s manufacturing textiles, yarns, paper goods, and wire works. Three electricity generating plants are worth noting: The Oil City Dam, located about a 1.5 miles upstream of the present day Rainbow Dam, generated electricity in the latter part of the 1800s. This plant burned to the ground in 1897 but was immediately rebuilt of brick. Also located on this section was the Farmington River Power Company which transported electricity 11 miles to Hartford. This facility, financed and constructed by Edward Clinton Terry, was the first hydro-electric plant in the world to transport energy a long distance. You can still see the remains of the bridge abutments for this dam. Today, the Farmington River Power Company, a subsidiary of The Stanley Works, owns and operates an active hydroelectric facility at the Rainbow Dam. The facility began operating in 1925 and still relies on the original turbines to generate power. Tours of the plant are available through The Stanley Works.

Life Along The River

This section begins at Rainbow Reservoir where The Stanley Works maintains a hydroelectric facility complete with a fish ladder for those species which travel up the river from Long Island Sound in the spring to spawn. Along this route in late spring and early summer, you should see the following fish headed for the dam: salmon, sea lamprey, American shad, alewife, blueback herring, sea-run trout, and striped bass. As you near the Connecticut River, you may even see some dead sea lamprey which have finished spawning.

This part of the river is also great for bird watching. Look for double-crested cormorants flying close to the water. High in the trees, watch for osprey, great blue herons, and kingfisher. Keep an eye out for red tailed hawk and eastern screech owls which use tree cavities as their homes along the riverbanks. Other fish-eating animals in this area include muskrat and wood duck. In the spring, look at the branches of trees for the signs of tent caterpillars. These fuzzy critters favor apple and cherry trees and often survive as most birds find them unpalatable. However, in years of heavy infestation, watch for both yellow-billed and black-billed cuckoos which feed on tent and other caterpillars including the gypsy moth. In Windsor, near the Loomis-Chaffee School, look for leopard frogs just before the Farmington meets the Connecticut River.


Rainbow Reservoir is a long, narrow, 235 acre body of water which provides Hartford area residents with sport fishing and boating opportunities. Rainbow produces good catches of both largemouth and smallmouth bass despite sparse vegetative cover. Also, the Reservoir supports large populations of spottail shiners and golden shiner which provide forage for the bass. In addition, you will find pumpkinseed sunfish, bluegill sunfish, rock bass, and calico bass here. American shad use the Rainbow Dam fishway to enter the reservoir and spawn. Some shad have been known to migrate and spawn as far upstream as Rt.4 in Farmington.

There are two fish passages around the Rainbow Dam, one for traveling upstream and one for traveling downstream. The CT Department of Environmental Protection manages these fish passages, counting and catching fish on their spring migrations. There is a public viewing area at the upstream ladder and the DEP holds an annual open house for the public in early June. The dam can be reached from Rainbow Road in the Pequonock section of Windsor.

The hydropower generation schedule at Rainbow Dam strongly influences the fish population and other wildlife downstream. Releases of water from the dam are erratic and these flow fluctuations reduce the numbers of nearly all aquatic plant life forms and aquatic insects. One can expect resident fishes to be similarly impacted.

In the lower Farmington River, much of the fishing is dependent on the migration of fish into the Farmington from the Connecticut River. Fresh water species including northern pike, largemouth bass, smallmouth bass, white catfish, and channel catfish move freely in and out of the relatively cool waters of the Farmington River. Also, white perch are caught in large numbers during the spring. Brown trout can also be found near the mouth of the Farmington River in shoreline cover during both the spring and fall. These are mostly two and three year old trout which average 8-10 inches in length. The most important fisheries here, however, are for American shad, alewife, blueback, and Atlantic salmon which return from sea to spawn in the Farmington River during the month of May.


This area is part of the Connecticut River valley’s old glacial lake which was formed during the glacial periods. The alluvial deposits and clay which were left when the glaciers retreated were used significantly in Windsor’s and South Windsor’s brick making industry.