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Show Chapter 2 The River, Its Tributaries, and Other Water Sources The Connecticut is New England's largest river. Rising near the Canadian boundary, it flows through four States on its way to the sea. Al- though a boisterous mountain stream in the upper tributaries, it becomes a tranquil river as it ap- proaches its destination in Long Island Sound. The Connecticut itself is 407 miles long, exceed- ing the length of its basin by 100 miles. It flows south through a long and narrow flood plain, fall- ing about 1,640 feet between First Connecticut Lake and tidewater at Hartford, Conn. Nearly two-thirds of this fall is in the upper third of the basin. In these upper reaches, numerous tributary streams tumble rapidly toward the river. The Connecticut flows near the middle of its narrow basin, and the 23 principal tributaries that flow into it are mostly short, swift streams with steep narrow valleys that extend back into the bordering mountains and hills. The larger tribu- taries are the Westfield, Farmington, Deerfield, Chicopee, White, and Passumpsic Rivers. In the lower reaches of the river the average annual flow is 16,000 cubic feet per second. This is equivalent to 22.6 inches of runoff, or about half the total precipitation. Approximately 13.3 million acre-feet are drained annually from an area of 9,719 square miles. Extreme variations in flow occur. Floods have developed in every month in the year, but they occur most frequently in spring. The maximum recorded flood discharge at Hartford is 313,000 cubic feet per second (March 1936). Floods often develop on the tributaries within a few hours or a day. Some tributaries may have a serious flood without causing floods on the main stem. Thus in 1929 a flash flood on the Mattabesset River caused extensive damage in New Britain, Conn., but did not affect the main stem. Because the lowlands are densely occupied, major floods have caused large property losses. The large floods on the Connecticut in 1927, 1936, and 1938, together caused damages totaling nearly 150 million dollars. Temporary retention of water in reservoirs and ponds along the river, especially during drought periods in late summer, causes the flow in the river to reach very low stages at times. A minimum monthly flow of 2,890 cubic feet per second was experienced at Hartford in September and October 1930. These low flows result in shortages of water for industrial processes, low power production, and increased pollution concentrates to the point where they become a nuisance at these periods, and indi- cate need for additional storage on the river for the most efficient use of water storage. At times in the history of settlement, shallow draft boats have operated as far north as East Rye- gate, Vt., but at present commercial navigation is limited to the reach below Hartford, Conn. The basin generally is not a notably abundant source of ground water, although conditions differ by districts. Local differences correspond mainly to geological differences. In the northern part of the basin, beginning approximately at the Vermont-New Hampshire- Massachusetts line, the underlying rock is granite. This is a nonwater-bearing rock and, therefore, the only opportunity to obtain large quantities of ground water is from glacial gravel deposits. From the Vermont line to Middletown, Conn., the underlying rock is predominantly red sandstone. While this formation may be considered as a fair aquifer, the quantities derived are not great. There are a few places, such as in the Springfield and Hartford areas, where ground water supplies are 471 |