GEOLOGY OF THE SHEPAUG AQUEDUCT TUNNEL,, 

 LITCHFIELD COUNTY, CONNECTICUT 



William M. x\gar 

 Introduction 



The Shepaug tunnel bears in a general northwest-southeast 

 direction across that part of Litchfield County immediately south 

 of Litchfield village. It is designed to carry the waters of the 

 West Branch of the Shepaug River under the intervening hills 

 and the bed of Bantam Lake to the West Branch of the Naugatuck 

 River above the northern extremity of the Morris Reservoir, part 

 of the present Waterbury water system. 



The tunnel level is such that it comes to the surface at the 

 crossing of the Bantam River, two-fifths of a mile southwest of 

 Bantam village, and lies above bed rock in a low swampy area 

 one-quarter of a mile west of there. This made it possible to drill 

 the tunnel in three separate sections without sinking any shaft. 

 The westernmost section is a straight tunnel bearing south 81'' 27' 

 east. This part was drilled east from the valley of the Shepaug 

 at a point about one and a quarter miles north of Woodville — the 

 intake point — and west from the westernmost end of the swamp 

 referred to above. An open cut v/as made through the swamp 

 and this was later cemented and filled. A short section was 

 drilled west from the Bantam River crossing on the same bearing, 

 to meet the eastern edge of the swamp. The grade of this part 

 of the tunnel is 0.08%. 



The eastern section begins just across the Bantam River valley 

 and follows the same bearing for 6180 feet with a 0.5% grade to 

 the broad base of Dempsey's Point on the north shore of Bantam 

 Lake. From there it bears S. 35° 46' E. for 4540 feet, passing 

 under the lake and skirting the shore of Marsh's Point to the 

 bottom of the bay, and then turns again to S. 81° 30' E. and holds 

 that direction as far as the outfall above the Morris Reservoir. 

 The grade is 0.1% from the first corner to the outfall. This 

 section of the tunnel was drilled from the Bantam River and out- 

 fall ends and the tunnels met 2.15 miles from the outfall. 



The total length of the tunnel is 38235.67 feet or 7.24 miles and 

 all but the 570 feet under the marsh and the 697 feet at the 

 Bantam River crossing are drilled through solid rock. The 

 difference in elevation between the intake and outfall amounts to 

 62 feet. 



Topography and Drainage 



The region underlain by the tunnel lies near the center of the 

 western upland of Connecticut. It is maturely dissected with hills 



