River History

There are no records but lots of clues about what life was like along the Ipswich River before Europeans arrived in the 1630s. The once-wild river would have been fuller 400 years ago, fed by pond run-off, underground springs, and tributaries along its 45-mile meander from marshy headlands, through red maple swamps, white pine forests and chestnut groves, until, swelled and teeming with life, it reached the ocean. For thousands of years, the river had hosted diverse ecosystems – lumbering black bear in the swamps to microscopic amoeba in the gentle backwaters. When, in 1638, John Winthrop bought the lands along the river and exclusive fishing rights from Chief Masconomet for 20 pounds sterling, a new history was about to be written for those free-flowing waters.

Forces Shaping the Land

The formation of what became a 155 square mile basin for the Ipswich River began in the Pleistocene Era, some l0,000 years ago. Thick glaciers gushed up ridges, deposited loads of sand and gravel, and gouged a bowl-shaped depression in the land creating the eventual watershed. Melting ice and snow converged in trickles, brooks, and streams and was finally channeled into one river bent on reaching the lowest elevation – sea level.

The region was covered by ice thousands of feet thick. The ice didn’t just sit still, but flowed, as glaciers do, bulldozing and scouring the land, moving huge boulders and vast volumes of soil and rock, reshaping the landscape. Elongated hills called drumlins were formed this way; today they are the major upland feature of the watershed. The highest point in the watershed (and Essex County) is a drumlin called Holt Hill in Andover; and just to the east is Boston Hill, another drumlin, which used to have a downhill ski operation. The hills you drive over along Route 1 in Topsfield are other great examples of drumlins, as are Castle Hill at Crane Beach, and Great Neck and Little Neck at the mouth of the Ipswich River. You can even see the “innards” of drumlins at Little Neck and the southern end of Plum Island (both near the mouth of the Ipswich River), where ocean waves have eroded away soil, leaving the bigger rocks visible along the shore and in the coastal banks. Many other drumlins exist throughout the watershed, lending it a hilly nature, especially in the northern and eastern portions.

The glaciers also enlarged pre-existing valleys in the bedrock, which later filled with sands and gravels carried and sorted by meltwater as the glacier receded. The heavier gravels dropped out of the water first, then the smaller and lighter sands – thus the sediments carried by water were sorted by size. These soil formations can hold a lot of water even today; they are the main aquifers, or water-bearing layers of soil, which are important for water supply and the Ipswich River’s flow, especially in summer.

Eskers are sinuous low hills that look like low, curvy, narrow ridges. They are the sediments which settled out of streams of melting water flowing inside the glacier as it was melting. Eskers often occur within or adjacent to wetlands, and make great trails – mini-ridges amidst lowlands and ponds. Esker tails are located at the J.C. Phillips Sanctuary and Norwood Pond in Beverly, the Ipswich River Wildlife Sanctuary in Topsfield and numerous other properties.

Kettle hole ponds, like Silver Lake in Wilmington, Cedar Pond in Wenham and Rantoul Pond in Ipswich, were shaped by big chunks of ice, broken off the glacier and buried in the soil. When the ice melted, a pond basin was formed.

Other glacial features, such as moraines, kames, kame terraces, and outwash plains occur in the region.

So the main structure and topography of the watershed was set. The highest hills are in the northwest part of the watershed, now Andover, North Andover and Boxford; but the drumlins continue all the way to the easternmost limit at Plum Island Sound, providing spectacular outlooks over the ocean. The northwestern watershed “ridge,” defined by the discontinuous hills, causes water to flow southeasterly into the Ipswich, whereas raindrops spilling just north or west flow into the Parker and Merrimack basins. The tributary streams which flow from this area – like Fish and Boston Brook and the Skug River – have a steeper gradient than the main river channel itself, flowing down these hills.

The low relief of the main channel itself was also finished by glacial action, which left large aquifers in the “buried valleys” of Burlington, Wilmington, Reading and North Reading. The gradient of the main channel is almost flat, dropping only 115 feet over 45 miles from source to sea. This low gradient results in the watershed’s extensive wetlands, which cover about 1/5 of the terrain, and provide outstanding scenery and wildlife habitat.

Since the end of the last glacial period, water has been doing most of the work of shaping the land: draining downhill, carrying soil away by the ton each spring during floods. Small rivulets combined to make bigger ones, those to make streams and those came together to make the river. The river meanders through the wetlands, and slowly forms oxbow lakes when meanders are cut off. The river is dynamic, never following exactly the same course from year to year. Shifts in the location of the bank and the shape of the channel occur constantly, with floods playing a major role in scouring the channel and depositing rich sediments in the floodplains. The dynamic nature of this (and all) rivers, and their sensitivity, make it unwise to build upon floodplains.

Plant and Animal Life

Plant and animal life found their niches in and along the river after the glaciers receded. Alewives, shad and salmon battled upstream from the sea to spawn in the spring, trout and pickerel swam in the dark pools, and, at dusk, horn-pout and eels snapped for dinner. Among the mammals that abounded along the shore were black bear, beaver, river otter, mountain lions, lynx, wolverines, grey wolves and martens. Flocks of migrating passenger pigeons and Labrador ducks darkened the sky and wild turkey and woodcock scuttled in the underbrush.

Agriculture dominated the Ipswich River Watershed lands for centuries, but over the past 100 years the lands are reverting to regrowth forests, interspersed with fields, meadows, marshes, swamps (and housing developments, shopping centers, roads…). Fortunately, much land has been permanently protected here, especially in the northern and eastern areas of the watershed.

The watershed’s upland forests are dominated by white pine and mixed hardwoods. The large trees which occur here most frequently include pines (white and red are the most common); oaks (again, white and red); maples (red, sugar, silver, and the invasive Norway); ashes (white and green), beeches and some birches (mostly white, yellow, gray). Hemlock, some cedars, black cherry, hickories, butternut and walnut, aspens and relatives of the species mentioned are also common. Bring a simple tree key along, and you’ll learn the first group quickly, and can start on the second.

Swamps (or forested wetlands) are very common here — the watershed is almost 20% wetland, which is much higher than average. Red maple is the most familiar swamp tree. Its brilliant fall foliage lights up the watershed’s extensive swamps in September and early October. Other wetland trees include swamp white oak (different than the upland white oak), Atlantic and northern white cedar, green ash, elm, river birch, and willows. Even trees known as upland species may occur in swamps, as for example white pine, which occurs commonly in white pine swamps such as those at Willowdale State Forest.

A paddle down the Ipswich River in Middleton and Topfield will introduce you to interesting and lovely silver maple floodplain forest. The silver maples have buttressed (raised) roots to allow them to survive flooding without drowning the root system.

Another important forested plant community is the Atlantic white cedar swamp, a wetland type which is rare in Massachusetts. These highly valuable trees grow slowly, are susceptible to changes in water levels, and do not regenerate quickly. Massachusetts Audubon Society’s Cedar Pond Sanctuary in Wenham, and Willowdale State Forest protect Atlantic white cedar swamps.

Shrub swamps are another wetland type which is very important to the region’s ecology. Buttonbush, speckled alder, winterberry holly, sweet pepperbush, highbush blueberry, cranberry viburnum and red osier dogwood are some of the native species which you’ll find throughout the watershed. Invasive species, such as multiflora rose, European buckthorn, Oriental bittersweet and Morrow honeysuckle threaten to outcompete the native species in these shrub swamps.

Some of the low and non-woody plants which you’ll see in wetlands throughout this region are skunk cabbage, a harbinger of spring; tussock and other sedges (grass-like plants); cinnamon, marsh, sensitive and many other ferns; as well as wildflowers too numerous to list. Look for skunk cabbages beginning to emerge even in the snow of late winter – they can do this because they produce their own heat, keeping the core of the plant about 36 degrees F warmer than the outside air temperature!

Bogs are fascinating ecosystems which support plants and animals that do not occur elsewhere. Bogs are acidic and nutrient-poor wetlands, and the plants which have evolved successfully in bogs are able to survive these conditions. Pitcher plants and sundews have an interesting strategy for obtaining nutrients – they trap insects as their food source! Cranberry bogs are typically areas where sandy soils combine with high water tables and acidic conditions, supporting the growth of this American native plant. These bogs are uncommon in the Ipswich River Watershed. You can explore a quaking bog on a self-guided trail at the Ward Reservation in Andover.

The salt marsh and barrier beaches dominate the coastal region of the Ipswich River. The Ipswich River estuary is part of the Great Marsh, a natural resource of global importance and a key stop on the Atlantic flyway, a major bird migration path. Spartina alterniflora and Spartina patens are the dominant grasses along the coastal creeks. Sea lavender, orach and other plants have developed strategies to survive the mixing of salt and fresh waters, and the estuary remains one of the most ecologically-productive places on earth.

Two plants which you really should learn, if you are going to explore the watershed, are poison ivy and poison sumac. Poison ivy is very common here in all habitats inland and coastal, wet and dry; and can grow amazingly large and high!! Its distinctive 3-part leaf varies considerably in shape, color, glossiness and edging. All parts of the plant are toxic, causing the unfortunately too familiar itchy rashes. Learn to identify it throughout the seasons, and teach your kids!! (Kids are low enough to the ground to get exposed very easily.) Poison sumac is even more toxic, though less common. It is a wetland plant and does occur in some parts of the watershed. Another plant you may wish to learn (perhaps out of desperation) is jewelweed, also called “touch-me-not.” This plant is reputed to be an antidote to the toxins in the poison ivy/ poison sumac genus.

Human Interaction with the River

Hunting would have been rich for the Native Americans who called their shores “Pleasant Place By the Water.” Shell and fish bone heaps, arrowheads, fragments of clay dishes, stone pestles and blackened camp fire stones along the river tell us something of the centuries of nomadic life they lived, building bark-covered wigwams in the meadows next to ancient breeding fisheries. Doomed to starvation and disease when their chief bargained away the river and its bounty, Native Americans whose ancestors had lived in this area for generations all died off in fewer than 100 years.

Meanwhile, the colonists began harnessing the river. They built weirs to channel the current to water wheels powering grist and saw mills. By the mid-1700’s bridges criss-crossed the river, wharfs and storehouses dotted the shore of the navigable water, and a salt works, tannery and ship building yard were in operation. Fishing was the most profitable industry on the river, then called Agawam. In the growing port, now the town of Ipswich, ships from the West Indies unloaded molasses at the wharf. The barrels were rolled directly into a thriving distillery, the town’s second largest commercial operation.

A century later 450,000 yards of cotton, miles of lace, gallons of cider and thousands of woolen garments were being produced annually, along the river. The forests had been cut for lumber and fuel. The land was cleared for fanning and grazing animals. Dams and pollution were wreaking havoc on the freshwater fisheries and other wildlife. The once-green corridor had become an artery of frenetic commerce.

Today, despite the fact that non-point source pollution presents a serious threat to the river, there is hope that new regulations for river protection will ensure cleaner water, encourage threatened ecosystems, and protect endangered species, for tomorrow. The river basin that provides household water for 335,000 people remains a haven, though an altered one, for recreation. The mosaic of once-pristine natural habitats has been disrupted forever but a patient enthusiast can still be rewarded by the sight of a slippery blue-spotted salamander, a golden-winged warbler or basking Blandings turtle. And, reminding us that the building blocks of life start small, there is the whole world of aquatic bugs to investigate, too.

Of course, humans have made changes to the natural scheme of things. Now the Ipswich River is dammed in three places (and on numerous tributaries), which greatly changes the way it flows and functions. Many communities use its water, which leaves little or none for the river for part of each year. Paving and building upon the land means that water can’t sink in to replenish the aquifers, which are what gives the river its water when its not raining.