The Genesee Tunnel is an underground water

Water

Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 pipeline

Pipeline transport

Pipeline transport is the transportation of goods through a pipe. Most commonly, liquids and gases are sent, but pneumatic tubes that transport solid capsules using compressed air are also used....

 operated by the South Central Connecticut Regional Water Authority

South Central Connecticut Regional Water Authority

The South Central Connecticut Regional Water Authority is a public water supply utility in Connecticut, United States.The Authority supplies water in a 15-town region with a population of about 400,000. Historically it was the water supplier in the towns of Bethany, Branford, Cheshire, East Haven,...

 (formerly the New Haven Water Company), part of the Authority's source water distribution system. Its main inlet is housed in a small brick building on the shore of the west fork of the northern end of the Hammonasset Reservoir (41.3749°N 72.6187°W) on the Madison, Connecticut

Madison, Connecticut

Madison is a town in the southeastern corner of New Haven County, Connecticut, occupying a central location on Connecticut's Long Island Sound shoreline. The population was 18,812 at the 2000 census....

-Killingworth, Connecticut

Killingworth, Connecticut

Killingworth is a town in Middlesex County, Connecticut, United States. The town's name can easily be confused with another Connecticut town, Killingly; or a Vermont ski area, Killington. The population was 6,018 at the 2000 census.-History:...

 town line. The tunnel runs westward about 5 miles to a pond sometimes known as Menunkatuck Reservoir which is on posted Water Authority land (41.378°N 72.713°W) in North Guilford

Guilford, Connecticut

Guilford is a town in New Haven County, Connecticut, United States, that borders Madison, Branford, North Branford and Durham, and is situated on I-95 and the coast. The population was 21,398 at the 2000 census...

.

The tunnel runs partly across a section of Water Authority land known as the Genesee Recreation area, located northwest of the intersection of Route 79

Route 79 (Connecticut)

Route 79 is a state highway in southern Connecticut from Madison to Durham.-Route description:Route 79 begins at US 1 in Madison center and heads north across I-95 . It continues north, intersecting with Horse Pond Road , which leads to the town offices...

 and Route 80

Route 80 (Connecticut)

Route 80 is a long secondary east–west state route in Connecticut from New Haven to Deep River. It serves as a more inland alternate route to US 1 in eastern New Haven County and Middlesex County.-Route description:...

, which is covered by 9 miles of hiking

Hiking

Hiking is an outdoor activity which consists of walking in natural environments, often in mountainous or other scenic terrain. People often hike on hiking trails. It is such a popular activity that there are numerous hiking organizations worldwide. The health benefits of different types of hiking...

 trails and is the site of the historic "Little Genesee Settlement." In this section there are two additional smaller inlets where the tunnel crosses beneath Dowd Hollow Brook and Iron Stream, consisting of simple iron grates covering pipes in which the ground water drains into the underground tunnel.