Ground Water in the Norwalk, Suffield, and Glastonbury Areas, Connecticut

Westport is one of the shore towns of Connecticut, and is near the middle of the Long Island Sound boundary of Fairfield County, just east of Xorwalk and midway between Bridgeport and Stamford. The area of the town is about 20 sqiuire miles. Most of Westport is cleared, but there are patches of woodland here and there which ag- gregate 1 square miles or a fifth of the total area of the town. The territory was taken from Fairfield, Xorwalk, and Weston and in- corporated as a separate town in 1835. In 1910 the population was 4,259, an increase of 242 over the population of 1900. There are about 217 inhabitants to the square mile. The following table shows the population at each census since the town was founded and also tlie percentage of change during the preceding decade : Population of Westport, 18.'t0-t910.'^ Year. Popula- tion. Per cent change. Year. Popula- tion. Per cent change. 1.S40 1,803 2,a51 3,293 3,361 +47' 4-24 -f 2 ISSO 3, 477 -1-3 1H,50 1S90 3,715 -f7 lSt)0 1900 4,017 +8 1S70 1910 4, 259 4-« a Connecticut Register and Manual, 1919, p. 641. 110 GROUND WATER IN NORWALK AKD OTHER x\REAS, CONE". For the first 35 years there was a rapid growth, which was due in part to the opening of the New York & New Haven Railroad in 1849, and in part to the establishment of manufactures of cotton and leather. Since then there has been a steady though moderate growth. Westport is now primarily a district of country residences belonging to New York people. It is probable that because of the nearness of New York City and the excellent transportation facili- ties the population of Westport will continue to grow. Westport is the principal settlement and is at the head of the estuary of Saugatuck Eirer. Nearer the mouth is the village of Saugatuck. A third settlement, Greens Farms, is on the Sound near the southeast corner of the town. There are about 70 miles of high- ways in the town. About 5 miles of the Boston Post Eoad, one of the State trunk-line highways, lies vrithin the area. There are also 3 or 4 miles of roads built with State aid. The grades are in gen- eral moderate, and the road surfaces are vreil kept. There is trolley connection from Westport village along the Boston Post Eoad to Bridgeport and Stamford, and along the west shore of Saugatuck River to Saugatuck, and thence eastward to Compo Beach. The main line of the New York, Nev\' Plaven & Plartford Railroad runs east and west across the town half a mile to a mile from the Sound shore. It has a station at Saugatuck known as " Westport and Saugatuck " and also a station at Greens Farms. There are post offices at Westport, Saugatuck, and Greens Farms, and rural de- livery from Westport to the outlying districts. The principal industries of Westport are agriculture and the manufacture of cotton twine, buttons, embalming fluid, undertaker's supplies, mattresses and cushions, hatter's leather, and starch. SUEFACE FEATURES. The features characteristic of the western higlilands of Connecti- cut are found in Westport in a form modified by nearness to the sea. The hills and ridges show a distinct north-south alinement. The hills a mile or so back from the shore are 100 to 180 feet high. The hills farther inland are higher, and the greatest elevation in the town is on a ridge in the northeast corner, which has its crest 240 feet above sea level. The valleys in general trend southward. The valley of Saugatuck River is at least 200 feet deep at Westport village. The rock walls rise 120 feet above the water level, and soundings for abutments for a new bridge showed that in places the rock floor is at least 80 feet below sea level. These facts show that the coast formerly stood higher than it does now and that it has been depressed. In this way the valley of the Saugatuck has been drowned and made an estuary. Mud Brook valley, though smaller, has had a similar history, and Sherwood Pond is its estuary. WESTPORT. Ill Most of Westport is ilraiiied hy Sau^atuck lliver, which enters the town near the northwest corner. Half a mile south of the Wes- ton town line it is joined by Aspetuck Iviver, Avhich flows |)arallel to the north boundary. Several other tributaries, includinjr its West Branch. Stony Brook, and Deadman Brook, enter Sau^atuck River. Sasco Brook. Mud Brook, and two other unnamed short bi'ooks drain the soutlieastern part of the town and dischartje directly into Lon^- Island Sound. A\" ATEIt-P.KARIKO FORM A'lION S. (7}}els^. — The following bedrock formations liave boon recoirnizcd in Westport:^ The Thonui^^ton granite gneiss, the Danbiny granodio- rite gneiss, and the Waterbury gneiss. All of the area west of Saiigatuck Eiver and a strip cast of the river 2 miles wide along the shore and 1 mile wide at the north !)oundary, an area a quarter to half a mile wide extending along vSasco Brook for •! miles above its mouth, and a little area in the northeast corner of the toAvn are underlain by the Thomaston granite gneiss. These areas aggregate over 13 square miles. The Thomaston is a typical granite gneiss composed of medium coarse grains of feld- spar quartz, flakes of black mica, and minor accessor}- minerals. The mic;i is more or less perfectly segregated in narroAv bands. The mica flakes are roughly parallel to one another and give the rock its cleaval'lc character. This rock is in general light gray in color, but some phases of it are pink. The Danbury granodiorite giieiss is similar to the Thomaston granite gneiss except that the black mineral is in large part horn- blende insteaid of mica. This formation underlies about 3^ square miles in a strip a mile and a quarter wide and including Prospect Hill. From Prospect Hill the band runs west and north-northwest to the Wilton town line. Tlie bedrock of the remainder of the town (3 square miles) is the Wuterbur}- gneiss. One patch, half a mile wide at its north end and a mile and a half wide along the Sound, extends northward 2 miles from Greens Farms. A second small patch lies near the north part of the east boundary. Originally this rock was a series of sand- stones and shales but was converted by metamorphism to a schist. Contemporaneouslj- with or subsequently to the metamorphism there was injected into it a great deal of igneous material. Most of these intrusions are thin granitic sheets that follow- the schistose layers or cross them here and there like dikes. About three-quarters of a mile west of Sasco Brook on the Boston post road there is a trap dike about 60 feet wide, which outcrops on both sides of the high- vvay and may be traced a little way beyond. 'Gregory, n. B., anrt Robinson, II. IT., rrelitninary geological mfi[) of Connecticut: Connecticut Geol. and Nat. Hist. Survey Bull. 7, 1007. 112 GROUJ^^D WATER IN NORWALK AND OTHER AREAS, CONN. All the bedrock formations of Westport carry water in the same way and in equal abundance. There are no porous zones of conse- quence, and there is no interstitial water. Water may be recovered in moderate amounts by means of drilled wells, a good many of which have been made in Westport. The water is carried in part in joints formed by the original cooling and shrinkage of the rock, and in part in fissures formed by the compressive stresses to which the rock has been subjected. The ground water of the overlying soil mantle is derived from rain water by absorption and is in part discharged into the maze of intercommunicating joints and fissures in the bedrock. The probability is that a drill hole sunk at any point will cut one or more of these water-bearing fissures within a rather short distance and obtain a satisfactory supply of water. Statistics of a number of such wells in Westport are given in the table on page 117. Till. — The mantle rock of the higher portions of Westport, com- prising three-fifths of the total area, is till — a dense deposit com- posed of rock flour, clay, silt, and sand, which form a matrix in which are embedded pebbles and boulders. The distribution of the larger fragments is entirelj^ fortuitous. The till was made by the abrading action of the glacier, which moved over the region in a southerly direction. The mantle of residual soil or decayed rock formed in preglacial time and some of the fresh, unweatliered rock below were scraped away and carried along by the ice. The load of debris was in part carried to the southern edge of the ice sheet, but most of it was plastered like a blanket over the glaciated rock surface. The weight of the ice sheet tended to pack the till, so that the grains interlock and make a dense, tough material. There are many minute interstices that are capable of absorbing part of the rain that falls. The water first soaks downward through the till until it is deflected horizontally, and then it moves along until it is naturally discharged again at the surface in springs or swamps. The water may also be artificially recovered by digging wells in the till. Late in October and early in I^ovember, 1916, 49 such wells were visited in Westport. Of these wells 25 are said by the owners to be nonfailing and 13 are said to fail. The reliability of the other 11 wells could not be ascertained. The data collected concerning these wells are tabulated in detail on pages 115-116 and are summarized in the following table : Summary of tvells dug in till in Westport. Total depth. Depth to water. Depth of water in well. Feet. 31.9 10.0 18.1 Feet. 24.8 6.9 14.7 Feet. 11 4 .6 3.4 WKSTroirr. 113 Sfiatifvd drift. — The low-lyino- portions of AVostpoit, !ii;i!;iv<;atin<:!j two-Ht'ths of the total area, are covered \\\\\\ stratified drift, whicli includes all niatoiials that have been sorted and deposited in beds and lenses, in each of which the sand or gravel is of essentially uniform size.