Genesee Tunnel
The Genesee Tunnel is an underground water pipeline operated by the South Central Connecticut Regional Water Authority (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 on the Madison, Connecticut-Killingworth, Connecticut town line. 
The tunnel runs westward about 5 miles to a pond sometimes known as Menunkatuck Reservoir which is on posted Regional Water Authority (RWA) land () in northern Guilford. 

The tunnel runs partly across a section of RWA land known as the Genesee Recreation area, located northwest of the intersection of Route 79 and Route 80, which is covered by 9 miles of hiking trails and is the site of the historic "Little Genesee Settlement." The Genesee Recreation area is accessible for hiking and fishing to anyone with an RWA Recreation Permit. 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 tunnel.