Excerpted from the "Open Space & Recreation Plan, Town of Reading, November 1996".
The Town of Reading, is composed primarily of igneous and metamorphic rock, with glacial deposits on that bedrock. Outcroppings appear generally on hilltops scattered around many parts of the central ridge in the southwest and central part of the Town. As the glacier of 10,000 years ago receded, it left behind debris that varies from boulder-rich till to fine-sorted sand. This debris forms a thin but regular cover on more than fifty percent of the Town's area, including most of the higher elevations.
The glacier also left behind kames, eskers and drumlins, and huge blocks of ice which, in turn, caused deposition and formation of deltas and edge terraces and allowed bottom siltation to accumulate in low-lying areas. Muck and peat deposits occurred in many areas of the Town, particularly along the entire north/south length of the eastern half (North and South Cedar Swamps and Timberneck Swamp), along what is now the Ipswich River at the northern end of the Town, and along the Aberjona River in the west-central part of the Town.
In general, the overall slope of the Town is from the high land of the south and west toward the low land of the north and east. Within this general orientation, the area encompasses the headwaters of the Saugus River on the southeast, and the Aberjona River on the west/central side or contributes to the Ipswich River on the north. Because of the uneven terrain, there are many smaller creeks, intermittent streams and wetlands throughout the town which in turn contribute to these river systems, but there are no significant lakes or ponds. Rainfall averages 42.5 inches a year, causing seasonal flooding during the spring, while low flows generally occur late in summer and early fall.
Early settlement of the Town of Reading was historically on high, dry areas, with lower and wetter areas left to be used as meadows, farms and woodlots. The Town was originally referred to as "Wood End" because of the abundance of trees which untimately were harvested for timber. Sand and gravel deposits have mostly been mined out or built upon, except for the protected areas such as the Town Forest, Bare Meadow and Cedar Swamp.
Prior to the 1970s, when the state wetlands protection laws were passed, significant portions of the Town were drained and filled to accomodate pressures for both residential and industrial development. the Aberjona River, in particular, has been channelized and riprapped so that in many areas it is no longer able to moderate and control the springtime flooding or the increased runoff that comes from housing development, ultimately resulting in increased flooding or the increased runoff that comes from housing development, ultimately resulting in increased flooding downstream. Thus houses built in such low lying areas now frequently have water problems in the basements and yards.