APPENDIX B: SUMMARY OF CCAMP AQUIFER ASSESSMENT COMMITTEE RECOMMENDATIONS 

 Cape Cod Aquifer Management Project Final Report Page B-4 



3. Water-evelation maps should be drawn from data obtained at both observa- 

 tion and non-pumping, supply wells. Maps constructed from data taken 

 at least every three months will reflect the seasonal fluctuations in 

 water-table elevations, flow directions and hydraulic gradients which 

 affect the geometry and orientation of a pumping well's zone of contri- 

 bution. In areas which have very gradual hydraulic gradients, hydrogeo- 

 logical conditions may require that elevation contours be drawn at 

 one -foot intervals to accurately reflect local groundwater flow pat- 

 terns in the vicinity of and upgradient of public-supply wells. (USGS, 

 CCPEDC, DEQE) 



II. RECOMMENDATIONS RELATING TO THE DELINEATION OF ZONE lis 



1. A demonstration of three-dimensional groundwater modeling is recommend- 

 ed. Ideally, the demonstration would include conditions where the 

 advantages and disadvantages of the modeling approach could be defined 

 and compared with those of the analytical approaches. Opportunities 

 for model verification with past and future water-level data should be 

 utilized. The models should be applied to areas with complex boundary 

 conditions, multiple aquifer systems, multiple withdrawal points, and 

 areally variable recharge, variable aquifer thickness, partial penetra- 

 tion, and changes in aquifer storage. Additional analyses could in- 

 clude comparison of the area of influence with area (zone) of contribu- 

 tion and determination of the upgradient boundary of the zone of contri- 

 bution. The subject of data acquisition in terms of requirements and 

 costs should be described. This will allow the determination of the 

 benefits of a more realistic model (more accurate Zone II delineation) 

 relative to the expense of collecting the data necessary to adequately 

 define such a model. Action item - financing is needed for a modeling 

 effort of this nature. (USGS, DEM/Division of Water Resources, DEQE, 

 CCPEDC) 



2. It is recommended that an evaluation of the existing hydrogeological 

 data base take place in the pilot area. No action- -EPA's Office of 

 Ground Water Protection generated an interim report entitled "Hydrogeo- 

 logical Considerations of Zone of Contribution Methods Used by Cape Cod 

 Planning and Economic Development Commission and SEA Consultants, Inc. 

 for Public Supply Wells in Barnstable, Massachusetts." (EPA) 



3. It is recommended that recharge data developed from Thornthwaite calcu- 

 lations be utilized in future delineations for Cape Cod. Sources of 

 this data are Strahler, Palmer, Guswa and LeBlanc. No action -- data 

 available. (DEQE -- guidelines for Zone II delineation, CCPEDC, USGS) 



4. It is recommended that transmissivity data be developed from well pump- 

 ing test data as outlined in the DEQE Guidelines for Public Supply 

 Wells. Action item - Guidelines are currently being updated. (DEQE) 



