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

Trap rock. — The trap sheets, which underlie narrow zones running north and south through East Granby, carry water in the same way as the sandstones and shales but rather less abundantly. Their topographic form is disadvantageous, as the bold cliffs allow the water to drain awaj'^ rather readily. Mr. George E. Bidwell's well (No. 12, PI. IV). for example, is 150 feet deep, but the water stands 75 feet below the mouth. In the other drilled wells in Suffield the average depth to water is only 22 feet, for there is little oppor- tunity for escape of water from them. 128 GROUND WATER IN NORWALK AND OTHER AREAS, CONN. Till. — Till forms a mantle over the higher portion of East Gx'anby except for the areas where bedrock actuallj outcrops and the talus slopes below the trap cliffs. The principal till area includes Peak Mountain and its prolongation southward and a lower westward extension, but there are also two small till-covered ridges in the northeast corner of the town. The till is composed of all the rock debris plowed up and scraped along by the glacier. It was deposited as a blanket 20 to 30 feet thick in general and comprises a matrix of fine rock flour, clay, silt, and sand in which are embedded pebbles, cobbles, and boulders of great and small size. Because of the pack- ing of the smaller particles into the interstices between the larger the till has only a moderate amount of pore space and the pores, moreover, are small. The deposit, then, is one of low porosity and low permeability. Nevertheless it has considerable value as a water- bearing formation and is able to store and slowly transmit moderate amounts of water. Wells dug in till are likel}^ to obtain fairly reliable and fairly abundant supplies of water. Six such wells were visited in East Granby, and of these three were said to be nonfailing, but the dependability of the remaining three was not ascertained. The following table summarizes the measurements made on these wells: Summary of ivells dug in till in Eaat Granhy. Total depth. Depth to water. Depth of water in well. Maximum Minimum , Average.. Feet. 27.9 7.0 18.4 Feet. 20.5 3.0 10.3 Feet. 18.6 3.2 8.1 Stratifed drift. — The deposits of stratified drift, of which the origin and distribution in East Granb}'' have been discussed above, is a far more efficient water-bearing formation than the till. It is composed in the main of the materials of the till reworked by run- ning water. The grains have been sorted out according to size and deposited in different beds. The finer particles have been removed from the interstices of the coarser, so that there is not only a greater percentage of pore space, but the individual pores are larger and connect more freely. Large amounts of water may be recovered from the stratified drift by means of dug or driven wells. Mr. J. S. Dewey's well (No. 3, PL IV) was made the subject of a roug'h pumping test (see p. 41) which showed a yield of at least 5 gallons a minute. Measurements were made of 20 wells dug in stratified drift in East Granby in July and August, 1916. Of these 17 were said to be nonfailing and 2 were said to fail, but the reliability of the EAST GKANBY. 129 other well was not ascertained. Tlic data eoncernini; tlie depths of these wells is siimniarized in the followinjLj tahle : i^tiimiiari/ of iceUs (lug in stratified drift in East (Iranfuj. Maximum Minimum. A veragc . . DcDth P^'P"' QUALITY OF CKOUXI) WATER. The results of two analyses and three assays of water collected in East Granby are given in the follovv^ing table. The waters are ail soft except No. 5, which is very soft, and No. ,33, wliich is hard in comparison with other waters of this area. All the winters are low in mineral content except No. 33, which is moderately mineralized. xVU are classified as good for domestic use, but the large quantity of nitrate in No. -3 may be an evidence of contamination. No. 5 is classified as good for use in boilers, but the rest are classed as fair because they contain considerable amounts of scale- forming constitu- ents. The waters ar« calcium-carbonate in type except No. 8, in wliich chloride is the dominant acid radicle. ChciiiicaJ comiKJuiiion and classification, of ground waters in East Granby.''' [Parts per million. Analyzed by Alfred A. Chambers and C. H. Kidwell. Numbers of analyses and assays correspond to those used on PI. IV.] Silica (SiO.) Iron (Fe) Calcium (Ca) Mafcnesium (Mg) Sodium and potassium (Na+K)^. Carbonate radicle (CO3) Bicarbonate radicle (HCO3) Sulphate radicle (SO4) Chloride radicle (Cl) Nitrate radicle (NO3) Total dissolved solids at 180° C Total hardness as CaCOs Scale-forming constituents g Foaming constituents g Chemical character Probability of corrosion i. Quality for boiler use — Quality for domestic use. Analyses. 6 dZ 13 1.4 27 •2.9 45 2,3 11 19 150 80 98 15 Ca-C03 ^^). Fair. Good. .68 14 2.6 7.0 .0 45 12 3.4 8.2 hSS f48 64 19 Ca-COa (?) Good. Good. Assays. Trace. !7l20 70 95 10 Ca-Cl Fair. Good. /20 7 .0 104 8.0 4.8 5 130 87 110 20 Ca-COa Fair. Good. /33 4 12 105 35 2.0 ffl90 137 160 10 Ca-COs ^•> Fair. Good. a For location and other descriptive information see pp. 130-131. b For methods used in analyses and accuracy of results .=ee pp. 52-60. <• Approximations; for methods used in assays and reliability of resuUs see pp. 52-60. d Collected Mar. 19. 1918. e Collected Nov. 18, 1916. / Collected Dec. 6, 1916. g Computed. h Total solids by summation. i Based on computed quantity; (?) = corrosion uncertain. 154444°— 20- -9 130 GROUND WATER IN NOR WALK AND OTHER AREAS, CONN. EECORDS OF WELLS AND SPRINGS. Only one spring was visited in East Granby. It is plotted on the map as No. 27 and is situated at the foot of a terrace scarp. The yield is large, and the water is pumped to a house. Wells dug in till in East Granny. No. on Pl.IV. Owner. J. W. Bidwell... Topo- graphic situation. Slope . . , do.. Plain.., Ridge.. Slope . . . Terrace . Eleva- tion Total Depth to Depth of water. above depth. water level. in well. Feet. Feet. Feet. Feet. 270 14.8 11.6 3.2 275 25.8 13.7 12.1 185 9.8 6.0 3.8 245 27.9 20.5 7.4 240 7 3 4 250 25.4 6.8 18.6 Rig Windlass rig and house pump. Chain pump do.... Windlass rig House pump Windlass rig. Remarks. Unfailing Do. Do. Wells dug in stratified drift in East Granhy. No. on Pl.IV. Owner. Topo- graphic situation. Eleva- tion above sea level. Total depth. Depth to water. Depth of wa- ter in well. Rig. Remarks. 1 Terrace.. ...do Feet. 270 195 200 150 150 170 195 195 205 195 200 190 210 205 195 180 185 160 195 185 Feet. 17.0 24.0 24.9 5.4 13.8 12.4 24.0 14.6 26.0 7.0 14.7 18.0 14.8 32.8 8.7 17.3 22.0 11.1 16.6 17.4 Feet. 15.5 21.5 21.8 3.1 8.5 8.9 20.1 11.5 17.1 4.7 6.4 14.0 13.1 29.4 6.4 12.6 9.9 7.7 14.3 14.6 Feet. 1.5 2.5 3.7 2.3 6.3 3.5 3.9 3.1 8.9 2.3 8.3 4.0 1.7 3.4 2.3 4.7 12.1 3.4 2.3 2.8 House pump Deep-well pump.. (a) Windlass rig.. Chain pump do Nonf ailing. 2 Nonfailing. In 3 8 9 J. S. Dewey Peter Bradley. . . Slope Plain Slope Plain Slope do . . rock 2 feet. Nonfailing. For analysis see p. 129. Nonfailing. For assay see p. 129. Fails. 14 Nonfailing. 16 Windlass rig Chain pump Windmill 17 Abandoned.6 18 Ridge.... Plain Swale Slope Ridge. . . . Plain do... Slope Plain.... do... Nonfailing. Do. 19 Chain pump do 20 Do. 21 Deep-well pump . . Two-bucket rig... do Do. 22 Do. 28 Nonfailing. Tem- 29 30 Griffin-New- berger To- bacco Co. Windlass rig and house pump. No rig perature, 55° F. Nonfailing. Fails. 31 Windlass rig Sweep rig Nonfailing. 32 H. Russell Do. 34 .. do.. . Deep-well pump . . Two-bucket rig. . . Do. 35 do... Do. a Pumping test made on this well. (See p. 41.) b Formerly this well did not fail. The recent construction of a railroad cut 10 feet north and 10 feet lower has interfered with its supply. ENFIELD. Drillcil ircllfi in East Granh)/. 131 g Owner. Topo- graphic situation. 0) S es fl'3 11 43 & •a 1 O P. o O 01 03 t; 0_; "oi 0).-. ft a 03 5 3 1 0) Kind of rock. Remarks. 4 0 6 11 J. S. Bewey tJeorge Jiatytes.. . Connecticut To- bacco Corp. William Laudroth. Slope... Terrace . Plain... Terrace . Slope... Feet. 210 190 170 160 445 Feet. 402 118 360 110 85 ISO 152 125 37 100 60 30 30 Indi- es. 6 6 6 lons. 10 3 + 30 3 Sandstone dc do do Trap (a) Foranalysis see p. 129. (») Water very hard. For assay see p. 129. c For assay see p. 129. 12 26 Geo: E. Kid well... L. H. Seymour... I. H. Griinn ...do 385 ...do.... 215 ...do ISO ""io' 75 5 6 6 6 11 19 do Trap and sand- stone. Sandstone a Water enough for drilling at 40 feet; gain of only 2 gallons a minute from 2CX) to 400 foot depth. 6 Drilled through 10 foot of sand, 4 or 5 feet of gravel, 45 feet of "blue clay," and 2 feet of "trap rock," and the rest iu sandstone. c Drilled through 10 feet of soil and 10 feet of trap rock and rest in sandstone. Windmill and gravity tank. d Well flows with a head of about 3 feet and with the outlet depressed IS inches; it flows IJ gallons a minute. Can pump 50 gallons a minute. ENEIELD. AREA, POPULATIOX, AND INDUSTRIES.