Clyde River (Vermont)
|- elevation||1,275 ft (389 m)|
|- location||Newport (city), Vermont, Orleans County, Vermont, USA|
|- elevation||682 ft (208 m)|
|Length||25 mi (40 km)|
|Basin||146 sq mi (378 km2)|
The Clyde River is a tributary of Lake Memphremagog, over 25 miles (40 km) long, in northern Vermont in the United States. It is the easternmost of the four major rivers in Orleans County. It is the most powerful of the four within Orleans County, powering several turbines at damsites. It is part of the Northern Forest Canoe Trail.
The river has its source in Spectacle and Island Ponds in Brighton. Runs northwest through Charleston and falls into Lake Memphremagog in Newport. With the exception of three miles (5 km) of rapids near its mouth, this is a very sluggish stream, passing through in its course, several natural ponds of considerable size. Even during spring high water, there is barely a perceptible current. The river is about 25 miles (40 km) long. It drains the water from about 146 square miles (378 km2).
Pherrin's River, which empties into the Clyde from the north about a mile below the outlet, frequently rises quite suddenly, swelling the waters of the latter so as to reverse its current and cause it to back up into Island Pond with great force for ten hours or more, until the pond is full, or the water subsides below, when it will again change and rush out.
The Clyde River is the largest in Charleston. It runs nearly through the center of the town. Some falls of importance are found on the stream, especially the Great Falls in the western part of the town, where the descent is more than 100 feet (30 m) in 66 feet (20 m); but its current is generally slow.
The principal tributaries of the Clyde are Pherrin's River from the north; another river, drains Suke's Pond, flows into it from the south; then the waters of Cold Brook from the south; Webster Brook flows into it from the west; the Clyde then turns northwest. Into it flows the stream from Cole's Pond in Brighton; Bald Mountain Brook, and Echo Lake Brook at the East village; next Fenner Brook from Westmore, then the Nutting Brook from Broadway pond, and Toad Pond Brook from Toad pond.
The Clyde then turns northward. An unnamed brook from Mud Pond empties into it. The Clyde then turns west, then north again. It empties into the south end of Pensioners Pond. 
Vermont routes 5A/105 parallels the Clyde from here on. It exits from Pensioners Pond and empties into the south end of Charleston Pond. It exits from the north of that pond and empties into Clyde Pond #1.
The Clyde River forms the principal water-course, flowing through the town from east to west.
After exiting from Clyde Pond #1, it proceeds westward. It empties into Lake Salem from the south. It exits the northwest corner of this lake. It is then joined by an unnamed brook from Derby Pond from the north. It then empties into Clyde Pond #2 from the northeast. It exits this Pond west and into south Lake Memphremagog from the north. The mouth is just east of where US 5/Vermont 105 crosses Lake Memphremagog.
Beaver populate the countryside and sometimes undercut the streamside silver maple, toppling them into the water thereby creating logjams.
The river winds through farm country, with silver maple and alder dominating the shoreline. Northern white cedar, an occasional willow, and a variety of shrubs line the 40-foot (12 m) wide waterway, and vegetation dips right into the water.
The river is in the Nulhegan Basin of northeastern Vermont.
In the early 19th century a mill dam constructed at Arnolds Falls. In 1883 a dam was constructed at the outlet to Lake Memphremagog. In 1918 the Newport Dam (Clyde Pond #2) was constructed. This dam was also known as Prouty Dam (after Governor Prouty). It was 713 feet (217 m) long. This was also known as the Clyde Pond dam.
The Echo Lake dam is used for hydroelectric power. Construction was completed in 1922. It has a normal surface area of 530 acres (2.1 km2). It is owned by Citizens Utilities Company. The dam is concrete. The core is homogeneous concrete. The foundation is rock. The height is 16 by 120 feet (4.9 by 36.6 m). Maximum discharge is 693 cubic feet (19.6 m3) per second. Its capacity is 5,000 acre feet (6,200,000 m3). Normal storage is 3,180 acre feet (3,920,000 m3). It drains an area of 24 square miles (62 km2).
In 1928 a dam was constructed at West Charleston. In 1929 a dam was built at Pensioner's Pond.
In 1957 #11 Dam was constructed. It was located 1,000 feet (305 m) below the current hydro generation station off Clyde Street. In 1994 the #11 Dam was breached. In 1996 the #11 Dam was removed. In 2007 a fish (salmon) passage was built at the Newport Dam
The following dams are on tributaries (watershed) that feed into the Clyde, and not the Clyde itself:
Lake Seymour is on a tributary which drains into Echo Lake, which in turn drains into the Clyde. It is used for hydroelectric power. Construction was completed in 1928. It has a normal surface area of 2.8 square miles (7.3 km2). It is owned by Citizens Utilities Company. This dam is stone, and concrete. The core is concrete. The foundation is soil. Its height is 7 feet (2.1 m) by 68 feet (21 m) long. Maximum discharge is 85 cubic feet (2.4 m3) per second. The capacity is 5,200 acre feet (6,400,000 m3). Normal storage is 3,500 acre feet (4,300,000 m3). It drains an area of 20.1875 square miles (52.285 km2).
List of cities and towns
In upstream order:
- West Charleston
- East Charleston
- Island Pond
- Sometimes called "Pitkin's Pond
- The Passumpsic River is also powerful, but is mostly outside of Orleans County
- James Whitelaw, eventual Surveyor-General of Vermont
- After which the town of Island Pond is named
- The pond was originally called "Knowles Pond" in the 19th century
- Gazetteer of Lamoille and Orleans Counties, VT.; 1883-1884, Compiled and Published by Hamilton Child; May 1887
- Was once called Ferrin's River
- Formerly known as Cole's Copper Brook
- Morgan Gull Brook
- Mad Brook from Westmore feeds into Bald Mountain Brook
- There are two Clyde Ponds. This one is the original. The one in Derby near the city of Newport was formed by a dam and is referred to here as #2. Generally when "Clyde Pond" is referenced, it is the second one, which is larger,
- Johnson, Charles W. (1984). The Nature of Vermont. University Press of New England.
-  retrieved November 28, 2008
- Map of Clyde River
- "Basin 17:Lake Memphremagog Watershed Assessment Report". Vermont Agency of Natural Resources,Department of Environmental Conservation, Water Quality Division. March 2006.