APPENDIX C: WATER-TABLE ELEVATIONS IN EASTERN BARNSTABLE, MASSACHUSETTS 

 Cape Cod Aquifer Management Project Final Report Page C-3 



feet of the shore. Depths to water were subtracted from well elevations to 

 obtain the elevation of the pond surface. Because of its large size, 

 Wequaquet Lake was surveyed at two locations: in the northwest near a 

 public landing on Shootflying Hill Road and in the south at the herring 

 run at Phinney's Lane and Melody Pond. On May 13, 1987, the observed 

 elevations of the lake surface at these locations were 34.45 and 34.44 

 feet above sea level, respectively. 



A map of water-table elevations was superimposed on the 7.5 minute Hyannis 

 quadrangle. Contours of equal elevations were drawn at five foot intervals 

 from 10 to 35 feet and one foot intervals from 35 to 38 feet. Contours 

 were dashed where approximate. In producing the contours, the location, 

 size and shape of surface-water bodies, including ponds, rivers, wetlands 

 and tidal estuaries, were considered. For example, kettle hole ponds, 

 which were originally sites of large blocks of melting glacial ice in 

 outwash sediments, are surface expressions of the water table. Because of 

 their essentially level surfaces, contours were drawn around the shore- 

 lines of these and other surface-water bodies. 



Discussion 



Elevation of ground water in eastern Barnstable and western Yarmouth 

 ranged from sea level along Cape Cod Bay and Nantucket Sound to 38.82 feet 

 at observation well W-7 (No. 27), approximately 0.5 mile northwest of the 

 waste water treatment facility. Wells located along the shoreline are 

 subject to tidal effects which range from 3.1 feet in Nantucket Sound to 

 9.5 feet in Cape Cod Bay (USGS , 1979). 



Because of high precipitation during the winter and spring of 1987, the 

 water table rose to record levels in May at several locations in the study 

 area. AlW 230 (No. 62), which has been used since 1958 as an observation 

 well, had a record high water-table elevation of 21.99 feet on May 20th. 

 Observation wells AlW 247 (No. 63) and YAW 85 (No. 61) were also at record 

 levels. Past measurements indicate that water-table elevations at these 

 locations can fluctuate from 5 to nearly 8.5 feet over their periods of 

 record. 



Barnstable has 31 public -supply wells which provide potable water to its 

 residents. Seventeen of these wells and three in Yarmouth are located in 

 the study area. Pumping wells create cones of depression in the water 

 table around their well casings. In eastern Barnstable they may range in 

 size from about 250 to 2900 feet in diameter. The size and magnitude of 

 these drawdown cones change in response to pumping rate and duration and 

 can perturb ground water gradients. To help mitigate the effects of well 

 pumping, the water table was measured before the onset of the summer 

 months of peak demand. Only three wells were known to be operating during 

 the observation period: Mary Dunn No. 2, Simmons Pond and Airport No.l. 

 During the period of field measurement, only observation wells located 

 outside of these wells' areas of influence were used. 



The configuration of the water table in eastern Barnstable has several 



