Great Bay (New Hampshire) facts for kids
Great Bay is a large tidal estuary in eastern New Hampshire, United States. An estuary is where fresh river water mixes with salty ocean water. Great Bay covers more than 6,000 acres (about 24 square kilometers). Many rivers flow into it. The bay's water then flows into the Piscataqua River, which leads to the Atlantic Ocean near Portsmouth, New Hampshire. The northern part of the bay, closer to the ocean, is called Little Bay.
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Geography of Great Bay
Great Bay is part of the Gulf of Maine watershed. It is like a "drowned river valley," meaning old river valleys were flooded by rising sea levels. This area has strong tides, deep channels, and wide mudflats.
The entire estuary stretches about 12 miles (19 km) inland from the mouth of the Piscataqua River. Several important rivers flow into Great Bay. The main ones are the Lamprey, Squamscott, and Winnicut. Other rivers like the Cocheco, Salmon Falls, Bellamy, and Oyster also add water to the system.
The Piscataqua River forms the border between New Hampshire and Maine. It connects Great Bay to the Atlantic Ocean. The tides in Great Bay are very strong. The bay is about 9 feet (2.7 meters) deep on average, but some channels go down to 58 feet (17.7 meters). At high tide, the water surface covers about 8.9 square miles (23 square kilometers). But at low tide, it shrinks to 4.2 square miles (10.9 square kilometers). This means more than half of the bay's bottom is exposed when the tide is out!
Amazing Natural Habitats
The Great Bay Estuary connects to the Atlantic Ocean at the mouth of the Piscataqua River. Twice a day, ocean tides bring salt water into the estuary. This salty water mixes with the fresh water from the rivers. Great Bay is one of the largest estuaries on the Atlantic Coast. It is also one of the deepest inland, reaching 10 miles (16 km) from the ocean.
About 14,000 years ago, huge glaciers melted. This caused ocean levels to rise. The rising water flooded the river valleys, creating the Great Bay we see today.
Great Bay has five main types of water habitats:
- Eelgrass meadows
- Mudflats
- Salt marshes
- Channel bottoms
- Rocky intertidal areas
These habitats are home to many creatures. You can find 162 types of birds, fish, and plants here. Twenty-three of these species are threatened or endangered. There are also countless small animals without backbones (invertebrates) and even harbor seals visiting sometimes.
Eelgrass Meadows
Eelgrass is one of the few flowering plants that grow underwater in the ocean. It is very important for the estuary. Eelgrass beds provide a safe home for many organisms, especially young fish and invertebrates. The roots of eelgrass help hold the bottom sediments in place. The plants also help keep the water clean and clear by filtering it. They use extra nutrients for their own growth.
Mudflats
When the tide is low, more than half of Great Bay becomes exposed mudflats. These muddy areas are full of life! Worms, soft-shelled clams, mud snails, and green crabs live here. Wading birds and horseshoe crabs also use the mudflats. They come to feed, reproduce, and find protection from predators.
Channel Bottoms
The deeper parts of the bay are called channel bottoms. When the tide goes out, fish and invertebrates often move into these channels. Oysters, which are special animals that only live in estuaries, prefer the channel bottom habitat.
Rocky Intertidal Zones
Rocky intertidal areas are places where rocks are covered by water at high tide and exposed at low tide. These rocks provide a firm place for seaweeds, barnacles, and ribbed mussels to attach. In winter, much of the seaweed gets trapped in ice. When the ice breaks up in spring, the seaweeds are torn from the rocks. They then become food for other creatures in the bay.
A Rich Cultural History
Native Americans were the first people to live along the shores of Great Bay. They used the bay's rich resources for survival. They found plenty of fish, shellfish, waterfowl, and mammals.
In the early 1600s, European settlers arrived. They also used the bay's resources. They found the tides helpful for moving their goods. A special flat-bottomed boat called a gundalow was invented. It used the tides to carry heavy loads in the shallow waters.
Gundalows carried many types of cargo. They moved saltmarsh hay, lumber, fish, clay, and textiles. Salt hay, harvested from the shores, was used for animal food and bedding. Sawmills along the tidal rivers produced lumber. This lumber was sent to other U.S. ports. Evidence shows that the bay was once covered by inches of sawdust from these sawmills! Brickyards also used the blue marine clay from the estuary shores to make bricks. These bricks were used to build homes and businesses all over New England. Cotton mills, important during the Industrial Revolution, were built near gundalow ports.
Great Bay was used a lot for business throughout the 1800s and early 1900s. Factories like gristmills and tanneries on the rivers caused a lot of water pollution until the mid-1900s. In 1973, a businessman wanted to build a large oil refinery in Durham, New Hampshire, right on Great Bay. But local citizens worked together to stop the project. They voted against it by a huge margin, showing the power of local communities.
Why Great Bay is Important
The Gulf of Maine, which includes Great Bay, is seen as one of the cleanest marine environments on the East Coast of the United States. It is also one of the most productive water bodies in the world. This is because of its water flow and the many seaweeds, salt marsh grasses, and tiny phytoplankton that grow there. For a long time, fishing was a major way for people to earn a living here. More recently, jobs related to recreation and tourism have also become very important to the region's economy.
Great Bay Reserve
The Great Bay National Estuarine Research Reserve protects many parts of the bay's shoreline. It includes salt marshes, rocky shores, cliffs, woodlands, open fields, rivers, and tidal waters. This reserve helps keep the Great Bay estuary healthy and safe for future generations.
