Prepared in cooperation with the Massachusetts Department of Environmental Protection
Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Southeastern Massachusetts
70°33' 70°
Plymouth-Carver model
71° 42° 73°
42°30’ MASSACHUSETTS
42°
0 50 MILES 0 50 KILOMETERS Study areas
Eastern Cape (Monomoy) model
Western Cape (Sagamore) model 41°45'
EXPLANATION Simulated pond Simulated stream
0 5 10 MILES
0 5 10 KILOMETERS
Base from U.S. Geological Survey and Massachusetts Office of Geographic Information data, 2001 Massachusetts State Plane Coordinate System, mainland zone 19, North American Datum 1983, 1:25,000
Scientific Investigations Report 2015–5168
U.S. Department of the Interior U.S. Geological Survey Cover. Map showing the extents of the three regional groundwater flow models of the Plymouth-Carver, western Cape (Sagamore flow lens), and eastern Cape (Monomoy flow lens) aquifers in southeastern Massachusetts. Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Southeastern Massachusetts
By Carl S. Carlson, Donald A. Walter, and Jeffrey R. Barbaro
Prepared in cooperation with the Massachusetts Department of Environmental Protection
Scientific Investigations Report 2015–5168
U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior SALLY JEWELL, Secretary U.S. Geological Survey Suzette M. Kimball, Acting Director
U.S. Geological Survey, Reston, Virginia: 2015
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Suggested citation: Carlson, C.S., Walter, D.A., and Barbaro, J.R., 2015, Simulated responses of streams and ponds to groundwater withdrawals and wastewater return flows in southeastern Massachusetts: U.S. Geological Survey Scientific Investigations Report 2015–5168, 60 p., http://dx.doi.org/10.3133/sir20155168.
ISSN 2328-0328 (online) iii
Contents
Abstract...... 1 Introduction...... 1 Hydrologic Setting...... 2 Methods of Investigation...... 6 Groundwater Flow Models...... 7 Development of Contributing Areas...... 9 Simulated Responses of Streamflows and Pond Levels to Pumping and Wastewater Return Flows...... 15 Alteration of Streamflows at Subbasin Outlets...... 15 Long-Term Average Conditions...... 15 Predevelopment Conditions...... 15 Pumping Only Conditions...... 19 Pumping With Wastewater Return Flow Conditions...... 19 Average Monthly Conditions...... 19 Predevelopment Conditions...... 19 Pumping Only Conditions...... 25 Pumping With Wastewater Return Flow Conditions...... 25 Alteration of Streamflows at Stream Model Cells...... 31 Alteration of Pond Levels...... 31 Long-Term Average Conditions...... 31 Average Monthly Conditions...... 31 Landscape Characteristics in Contributing Areas...... 35 Limitations...... 43 Summary...... 49 References Cited...... 50 Appendix 1. Development of Transient Groundwater Models for Cape Cod...... 54 Appendix 2. Simulated Changes to Streamflows and Pond Levels...... 57 Appendix 3. Landscape Characteristics in Simulated Groundwater Contributing Areas to Streams...... 59
Figures
1. Map showing the extents of the three regional groundwater flow models of the Plymouth-Carver, western Cape, and eastern Cape aquifers in southeastern Massachusetts...... 3 2. Map showing distribution of wastewater return flow areas and production well locations for pumping and recharge conditions in the Plymouth-Carver model area in southeastern Massachusetts from 2000 through 2005...... 4 3. Map showing distribution of areal recharge, wastewater return flow areas, and production well locations for pumping and recharge conditions in the western Cape and eastern Cape models in southeastern Massachusetts for 2003...... 5 iv
4. Schematic diagram showing generalized groundwater contributing areas in southeastern Massachusetts defined as A, hydrologic units and B, subbasins for simulating responses of streams and ponds to groundwater withdrawals and wastewater return flows...... 11 5. Map showing simulated hydrologic units for streams and surface-water-connected ponds in the Plymouth-Carver, western Cape, and eastern Cape model areas in southeastern Massachusetts...... 12 6. Map showing simulated headwater subbasins for streams and surface-water- connected ponds in the Plymouth-Carver, western Cape, and eastern Cape model areas in southeastern Massachusetts...... 13 7. Map showing simulated subbasins for streams and surface-water-connected ponds in the Plymouth-Carver, western Cape, and eastern Cape model areas in southeastern Massachusetts...... 14 8. Graph showing simulated long-term average streamflows for predevelopment, pumping only, and pumping with wastewater return flow conditions for each subbasin in the Plymouth-Carver, western Cape, and eastern Cape model areas in southeastern Massachusetts...... 17 9. Graph showing simulated long-term average streamflows normalized by subbasin area for predevelopment, pumping only, and pumping with wastewater return flow conditions for subbasins in the Plymouth-Carver, western Cape, and eastern Cape model areas in southeastern Massachusetts...... 18 10. Graphs showing percentage simulated changes in long-term average streamflow at the outlets of subbasins in southeastern Massachusetts from predevelopment conditions for A, pumping only or B, pumping with wastewater return flow conditions at the outlet of each subbasin...... 20 11. Graph showing August streamflows under predevelopment, pumping only, and pumping with wastewater return flow conditions at subbasin outlets in the Plymouth-Carver, western Cape, and eastern Cape model areas in southeastern Massachusetts...... 23 12. Graph showing August streamflows normalized by subbasin area under predevelopment, pumping only, and pumping with wastewater return flow conditions at subbasin outlets in the Plymouth-Carver, western Cape, and eastern Cape model areas in southeastern Massachusetts...... 24 13. Graph showing simulated percentage alteration of average monthly streamflows for subbasins in the Plymouth-Carver, western Cape, and eastern Cape model areas in southeastern Massachusetts...... 26 14. Map view of simulated alteration of average August streamflow for subbasins in the Plymouth-Carver, western Cape, and eastern Cape model areas in southeastern Massachusetts for pumping only conditions compared with predevelopment conditions at the outlet of each subbasin...... 27 15. Graph showing simulated alterations of August streamflows for pumping only and pumping and wastewater return flow conditions compared with predevelopment conditions in the Plymouth-Carver, western Cape, and eastern Cape model areas in southeastern Massachusetts...... 28 16. Graph showing simulated alterations in average January, April, August, and October streamflows for pumping with wastewater return flow conditions compared with predevelopment conditions at the outlets of subbasins in the Plymouth-Carver, western Cape, and eastern Cape model areas in southeastern Massachusetts...... 29 17. Map view of simulated alterations of average August streamflow for subbasins in the Plymouth-Carver, western Cape, and eastern Cape model areas in southeastern Massachusetts for pumping with wastewater return flow conditions compared with predevelopment conditions at the outlet of each subbasin...... 30 v
18. Maps showing simulated effects of pumping with wastewater return flow on average August streamflow in stream cells in the Plymouth-Carver model area in southeastern Massachusetts compared with streamflows under predevelopment conditions A, in absolute values and B, as percentage change...... 32 19. Maps showing simulated effects of pumping with wastewater return flow on average August streamflow in stream cells in the western Cape model area in southeastern Massachusetts compared with streamflows under predevelopment conditions A, in absolute values and B, as percentage change...... 33 20. Maps showing simulated effects of pumping with wastewater return flow on average August streamflows in stream cells in the eastern Cape model area in southeastern Massachusetts compared with streamflows under predevelopment conditions A, in absolute values and B, as percentage change...... 34 21. Maps showing simulated changes to average August pond water levels due to A, pumping only and B, pumping with wastewater return flow conditions for the Plymouth-Carver model area in southeastern Massachusetts...... 36 22. Maps showing simulated changes to average August pond water levels due to A, pumping only and B, pumping with wastewater return flow conditions for the western Cape model area in southeastern Massachusetts...... 37 23. Maps showing simulated changes to average August pond water levels due to A, pumping only and B, pumping with wastewater return flow conditions for the eastern Cape model area in southeastern Massachusetts...... 38 24. Hydrographs from the Plymouth-Carver model area of simulated average monthly pond levels for predevelopment, pumping only, and pumping with wastewater return flow conditions for A, Goose Pond and B, Triangle Pond in southeastern Massachusetts...... 39 25. Graphs showing comparison of A, channel slope, B, percent wetland in a 787.4-foot buffer, C, August withdrawal ratio, and D, percent impervious cover for Massachusetts water indicator subbasins, fish sampling site subbasins, and southeastern Massachusetts hydrologic units and subbasins...... 41 26. Graphs showing comparison of A, percent forest, B, drainage area, C, percent sand and gravel, D, undammed stream length, and E, percent open water for fish sampling site subbasins and southeastern Massachusetts subbasins...... 42 27. Maps showing simulated effect of pumping and percentage change on November streamflow compared with predevelopment conditions for A, the existing model and B, the alternative analysis with no pond outlet flow from Silver Lake to the Jones River area in southeastern Massachusetts...... 44 28. Maps showing simulated effect of pumping with wastewater return flows and percentage change on November streamflow compared with predevelopment conditions for A, the existing model and B, the alternative analysis with no pond outlet flow from Silver Lake to the Jones River area in southeastern Massachusetts...... 45 29. Graphs showing simulated November streamflow and change in November streamflow compared with predevelopment conditions for two sites on the Jones River from simulations of A, existing model and B, the alternative analysis with no pond outlet flow from Silver Lake to the Jones River in southeastern Massachusetts...... 46 vi
Tables
1. Simulated hydrologic budget for predevelopment and for pumping only and pumping with wastewater return flow conditions from 2000 through 2005 in the Plymouth-Carver aquifer system in southeastern Massachusetts...... 6 2. Simulated hydrologic budget for predevelopment and for pumping only and pumping with wastewater return flow conditions in 2003 in the western Cape and eastern Cape models of Cape Cod in southeastern Massachusetts...... 7 3. Stream identification, landscape characteristics, and simulated average streamflows for hydrologic units and subbasins in southeastern Massachusetts (Click here for link to http://dx.doi.org/10.3133/sir20155168)...... 10 4. Percent impervious cover and long-term average streamflow for hydrologic units in southeastern Massachusetts (Click here for link to http://dx.doi.org/10.3133/ sir20155168)...... 10 5. Summary of maximum simulated streamflows and the percentages of stream cells with streamflows within specific ranges under predevelopment conditions for long-term average and monthly simulations of the Plymouth-Carver, western Cape, and eastern Cape models in southeastern Massachusetts...... 16 6. Summary of changes in pond levels under pumping only and pumping with wastewater return flow conditions compared with predevelopment conditions for the Plymouth-Carver, western Cape, and eastern Cape models in southeastern Massachusetts...... 21 7. Simulated streamflows for predevelopment, pumping only, and pumping with wastewater return flow conditions for long-term average and average January, April, August, and October conditions for the existing models and the alternative analysis with no pond outlet flow for the Plymouth-Carver and western Cape model areas, southeastern Massachusetts...... 48
Conversion Factors
Inch/Pound to International System of Units
Multiply By To obtain Length foot (ft) 0.3048 meter (m) mile (mi) 1.609 kilometer (km) Area square mile (mi2) 2.590 square kilometer (km2) Flow rate cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s) cubic foot per second per square mile 0.01093 cubic meter per second per square ([ft3/s]/mi2) kilometer ([m3/s]/km2) cubic foot per day (ft3/d) 0.02832 cubic meter per day (m3/d) million gallons per day (Mgal/d) 0.04381 cubic meter per second (m3/s) inch per year (in/yr) 25.4 millimeter per year (mm/yr) vii
Datum
Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88). Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83), unless otherwise noted.
Abbreviations
GIS geographic information system STR Streamflow-Routing [package] USGS U.S. Geological Survey WMA Massachusetts Water Management Act
Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Southeastern Massachusetts
By Carl S. Carlson, Donald A. Walter, and Jeffrey R. Barbaro
Abstract Pond in the Plymouth-Carver region to an increase (surcharge) of 18.2 percent at an unnamed tributary to the Centerville Water use, such as withdrawals, wastewater return River on western Cape Cod. In general, the relative effects of flows, and interbasin transfers, can alter streamflow regimes, pumping and wastewater return flows typically were larger in water quality, and the integrity of aquatic habitat and affect the subbasins with low streamflows than in the subbasins with the availability of water for human and ecosystem needs. high streamflows, and there were more depleted streamflows To provide the information needed to determine alteration than surcharged streamflows. Increases in streamflows of streamflows and pond water levels in southeastern in response to wastewater return flows were generally Massachusetts, existing groundwater models of the Plymouth- largest in subbasins with a high density of septic systems Carver region and western (Sagamore flow lens) and eastern or a centralized wastewater treatment facility. For average (Monomoy flow lens) Cape Cod were used to delineate monthly conditions, streamflow alteration results were similar subbasins and simulate long-term average and average spatially to results for long-term average conditions. However, monthly streamflows and pond levels for a series of water- differences in the extent of alteration by month were observed; use conditions. Model simulations were used to determine percentage streamflow depletions in most subbasins typically were greatest during the low-streamflow months of August the extent to which streamflows and pond levels were altered and October. by comparing simulated streamflows and pond levels under The percentages of the total number of ponds affected predevelopment conditions with streamflows and pond levels by pumping with wastewater return flows under long-term under pumping only and pumping with wastewater return flow average conditions in the modeled areas were 28 percent conditions. The pumping and wastewater return flow rates for the Plymouth-Carver region, 67 percent for western used in this study are the same as those used in previously Cape Cod, and 75 percent for eastern Cape Cod. Pond-level published U.S. Geological Survey studies in southeastern alterations ranged from a decrease of 4.6 feet at Great South Massachusetts and represent the period from 2000 to 2005. Pond in the Plymouth Carver region to an increase of 0.9 feet Streamflow alteration for the nontidal portions of streams in at Wequaquet Lake in western Cape Cod. The magnitudes of southeastern Massachusetts was evaluated within and at the monthly alterations to pond water levels were fairly consistent downstream outlets of 78 groundwater subbasins delineated throughout the year. for this study. Evaluation of streamflow alteration at subbasin outlets is consistent with the approach used by the U.S. Geological Survey for the topographically derived subbasins in the rest of Massachusetts. Introduction The net effect of pumping and wastewater return flows on streamflows and pond levels varied by location and included Water use, such as withdrawals, wastewater return no change in areas minimally affected by water use, decreases flows, and interbasin transfers, can alter streamflow regimes, in areas affected more by pumping than by wastewater return water quality, and the integrity of aquatic habitat and affect flows, or increases in areas affected more by wastewater the availability of water for human and ecosystem needs. In return flows than by pumping. Simulated alterations to long- Massachusetts, concern has grown in recent years about the term average streamflows at subbasin outlets in response to potential effects of alteration on water availability and aquatic pumping with wastewater return flows were within about habitat and the need for improved indicators of hydrologic 10 percent of predevelopment streamflows for most of the alteration. In 2010, the U.S. Geological Survey (USGS) subbasins in the study area. Alterations ranged from a decrease developed methods for estimating indicators of streamflow (depletion) of 43.9 percent at an unnamed tributary to Salt alteration and other measures of drainage-basin alteration for 2 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass.
1,379 subbasins in Massachusetts (Weiskel and others, 2010; of streams in southeastern Massachusetts into subbasins Massachusetts Department of Environmental Protection, of similar size to those used in Weiskel and others (2010) 2014a). In 2011, the USGS determined relations between fish for the rest of Massachusetts; a total of 78 groundwater assemblages and anthropogenic factors (such as estimated subbasins were delineated for the nontidal portion of streams streamflow alteration) and physical basin characteristics (such in southeastern Massachusetts by using this approach. as land use and impervious cover) for 669 fish sampling sites Streamflow and pond-level alterations were calculated relative in Massachusetts (Armstrong and others, 2011). These studies to a predevelopment (without pumping or wastewater return were used in part as scientific support for 2014 revisions to the flow) baseline condition. Simulations were conducted for Massachusetts Water Management Act (WMA; Massachusetts both long-term average and average monthly conditions. General Court, 2015) regulations; the WMA provides the Streamflow alterations were computed at the outlets of the basis for the regulatory framework that governs water 78 groundwater subbasins and at individual groundwater allocations in Massachusetts. Although the USGS studies are model cells used to represent the stream network in considered to be statewide assessments of potential indicators southeastern Massachusetts. Selected landscape characteristics of basin alteration, they are limited by a lack of streamflow computed for the topographically derived basins in the rest of and physical basin characteristic data in southeastern Massachusetts were also determined for the 78 groundwater Massachusetts, preventing this area from being fully subbasins delineated in this study. incorporated into the revised WMA regulatory framework. This report describes the methodology and results of the The coastal plain of southeastern Massachusetts, simulations used to evaluate the response of streams and ponds which consists of the Plymouth-Carver region and Cape to withdrawals and wastewater return flows in southeastern Cod (collectively referred to as southeastern Massachusetts Massachusetts. The report also describes the previously in this report), differs from the rest of the Commonwealth published groundwater flow models used in the analysis, the in terms of topographic relief and aquifer size. The coastal procedures used to delineate the areas of the groundwater plain is dominated by large sand and gravel aquifers and subbasins that drain to selected outlet points, and the simulated characterized by subdued topographic relief, whereas the rest changes in streamflows and pond levels in the coastal aquifers of Massachusetts is underlain by smaller valley-fill aquifers in of southeastern Massachusetts in response to pumping only drainage basins with greater topographic relief. In southeastern and pumping with wastewater return flows. The results in this Massachusetts, contributing areas to streams are referred to as report are expected to provide water resources managers with groundwater subbasins because their size is determined largely the information needed for estimating indicators of hydrologic by groundwater recharge rather than topographic divides. For alteration in southeastern Massachusetts. the statewide assessments of Weiskel and others (2010) and Armstrong and others (2011), the Sustainable Yield Estimator application (Archfield and others, 2010) was used to estimate streamflow in subbasins delineated by topographic relief. Hydrologic Setting However, the Sustainable Yield Estimator is not applicable to areas of low topographic relief in southeastern Massachusetts The Plymouth-Carver aquifer system (fig. 2) is bounded where groundwater and surface-water divides are not laterally to the east and south by the saline surface waters coincident (Archfield and others, 2010). Consequently, the of Cape Cod Bay and Cape Cod Canal. Drainage divides of statewide assessments of indicators of streamflow and basin the South and Green Harbor Rivers to the north and of the alteration did not include southeastern Massachusetts. Weiskel Winnetuxet and Weweantic Rivers to the west were used and others (2010) did estimate subbasins for 34 streams in in Masterson and others (2009) to represent the northern southeastern Massachusetts, but because these areas and their and western boundaries of this aquifer system (fig. 2). The associated basin alteration indicators were determined for the total active modeled area is about 290 square miles (mi2). entire nontidal portions of these streams, these results were not The groundwater flow systems on western and eastern Cape sufficiently detailed for the WMA regulatory framework. Cod (Sagamore and Monomoy flow lenses, respectively) To provide the information needed to determine are surrounded entirely by saline water—Atlantic Ocean to alteration of streamflows and pond water levels in the east, Cape Cod Bay to the north, Cape Cod Canal to the southeastern Massachusetts, the USGS, in cooperation with northwest, Buzzard’s Bay to the west, and Vineyard Sound to the Massachusetts Department of Environmental Protection the south (Walter and Whealan, 2005) (fig. 3). These two flow (MassDEP), conducted a study (fig. 1) that made use of the lenses are separated hydraulically by the Bass River. The total existing groundwater models of the Plymouth-Carver region active modeled area for Cape Cod aquifers is about 361 mi2. (Masterson and others, 2009) and western (Sagamore flow The sole source of freshwater to the aquifer systems lens) and eastern (Monomoy flow lens) Cape Cod (Walter and of southeastern Massachusetts is precipitation. The part of Whealan, 2005; Walter and Masterson, 2011). Groundwater precipitation that is not lost to evaporation or the transpiration models were used to delineate subbasins and simulate of plants and reaches the water table is referred to as aquifer streamflow and pond levels for various water-use conditions. recharge. An average recharge rate of 27 inches per year A streamflow criterion was used to divide the nontidal portions (in/yr) was used in the previously published groundwater Hydrologic Setting 3 10 MILES 70° 5 EXPLANATION Simulated pond Simulated stream 0 0 5 10 KILOMETERS 71° Eastern Cape (Monomoy) model Study areas 50 MILES 50 KILOMETERS 73° MASSACHUSETTS 0 0 Western Cape (Sagamore) model Western 42° 42°30’ 70°33' Plymouth-Carver model he extents of the three regional groundwater flow models of the Plymouth-Carver, western Cape (Sagamore flow lens), and eastern T he extents of the three regional groundwater flow models Plymouth-Carver,
Base from U.S. Geological Survey and Massachusetts Office of Geographic Information data, 2001 Massachusetts State Plane Coordinate System, mainland zone 19, North American Datum 1983, 1:25,000 42° 41°45' Figure 1. Cape (Monomoy flow lens) aquifers in southeastern Massachusetts. 4 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass.
70°47'30" 70°37'30" 38 37 Green Harbor River EXPLANATION 77 78 South River Marshfield Inactive model area 39 40 Pembroke 26 Surface water Hanson Unnamed pond 25 Model cells with water lines 14 near Town Forest 23 without sewering—Data are 76 from 2005 2224 19 17 18 Stream 74 Duxbury 20 15 Pumping well and identification 21 Island Creek number—See Masterson and Pond Silver others (2009, fig. 17, table 1–4a) Lake Island Creek 87 Active in 2005 Kingston Mill Pond Jones River Halls Brook 85 Inactive 42° Tussock Brook Halifax 29 Wastewater treatment facility Crossman 31 Pond 28 Soules Pond 27Goose Town Brook Pond 32 87 35 34 79 Billington Cape Cod Bay 45 Sea Plympton 33 Triangle Winnetuxet River 48 Pond 13 82 Bartlett 46 Pond 52 South 44 Triangle Pond 50 49 83 42 Kings Great Pond South 85 Beaver Dam Brook Pond Powderhorn 53 88 55 10 Pond 59 Negro Pond Indian Brook 86 43 Plymouth Halfway Carver unnamed tributary to Pond South Meadow Brook South Meadow Brook 47 54 Unnamed 56 tributary to 12 Salt Pond WWeweantic River 51 eweantic River 11 Little Indian 58 Herring Middleborough Brook75 River Pond River 81 57
Agawam ankinco 66 Great80 WWankinco 68 84 Herring 7 67 Pond 65 Maple Springs Brook Glen Charlie 8 9 6 62 Pond 64 60 63 4 5 Wareham 61 1 Rochester 70 3 73 Herring 69 2 River 71 Union 72 41°45' Pond Canal Sandwich Cod Bourne Cape 0 2 MILES Marion Unnamed tributary to 0 2 KILOMETERS Muddy Cove Base from U.S. Geological Survey and Massachusetts Office of Geographic Information data Massachusetts State Plane Coordinate System, mainland zone
Figure 2. Distribution of wastewater return flow areas and production well locations for pumping and recharge conditions in the Plymouth-Carver model area in southeastern Massachusetts from 2000 through 2005. Modified from Masterson and others (2009, fig. 14).
Hydrologic Setting 5 Atlantic Ocean Atlantic 69°55'01''
k
e
v
o Bay
wn C wn
o
Town Cove Town T Pleasant Orleans Unnamed pond near Frost Fish Cree Chatham
Wastewater treatment Wastewater facility (WWTF) Septic-system discharge Red River River Red Red Return flow WWTF Chatham Western Cape model boundary Western operating in 2003 Wells not operating in 2003 Wells Eastern Cape model boundary WWTF Orleans
Harwich
Hinckleys Pond Hinckleys Hinckleys Pond Hinckleys
Paddocks Pond Paddocks
Brewster Pond Paddocks
Pond Pond
Griffiths
Griffiths
Pond Pond
School House School School House School
EXPLANATION
Herring River River Herring Herring
Herring River Herring
Unnamed tributary to tributary Unnamed
Pond Pond
White White
Pond Pond Bakers
Lower Mill Pond Bakers Nantucket Sound Nantucket Stony Brook Bass River Pond Land Saltwater wetland Freshwater wetland Recharge areas Dennis
Eastern Cape (Monomoy) active model boundary Pond Pond Grassy Grassy Coles Pond Grassy
Upper Mill Pond
Yarmouth
Hawes Run Run Hawes Hawes
Simmons Pond Simmons
Run Pond Run
Pond Pond
Dunn Dunn
Mary Mary Mary
WWTF
Pond Pond
Long Long
10 MILES Simmons Pond Simmons Barnstable
Cape Cod Bay
Pond Pond
Shallow Shallow
Unnamed tributary
to Centerville River
Lake Lake
Wequaquet Wequaquet 10 KILOMETERS Barnstable
5
Pond Pond
Little Little
Marston Mills River
Little River Cape (Sagamore) Western active model boundary 5
Upper Shawme Lake Shawme Upper Santuit River
Lovells Pond Pond Lovells Lovells
Lower Shawme Lake Shawme Lower Mill Creek (Shawme Lake outflow) Lake (Shawme Creek Mill
Sandwich Mashpee River
Quashnet River River Quashnet Quashnet
Pond Pond
Mashpee-Wakeby Mashpee-Wakeby 0 0 Mashpee
Canal
Military
Pond Pond
Ashumet Ashumet
Cod Reservation
Massachusetts Cape Bourne WWTF
Falmouth
Pond Pond
Long Long
Falmouth
Brook
Brook Pond Pond
Grews Grews
Vineyard Sound Vineyard Herring Herring
Massachusetts Military Reservation WWTF Buzzards Bay Buzzards D istribution of areal recharge, wastewater return flow areas, and production well locations for pumping recharge conditions in the western Cape Base from U.S. Geological Survey Chatham, Cotuit, Dennis, Falmouth, Harwich, Hole, Mass. Hyannis, Onset, Orleans, Pocasset, Sagamore, Sandwich, and Woods topographic quadrangles, 1:25,000, [various years] Mercator grid, polyconic projection, zone 19 Universal Transverse North American Datum of 1927
70°41'52'' 41°49'09'' 41°30'11'' Figure 3. (Sagamore flow lens) and eastern Cape (Monomoy flow lens) models in southeastern Massachusetts for 2003. Modified from Walter and Whealan (2005, fig. 1–4). (Sagamore flow lens) and eastern Cape (Monomoy models in southeastern Massachusetts for 2003. Modified from Walter 6 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass. models of southeastern Massachusetts (Walter and Whealan, of 2003, about 380 Mgal/d (from an average recharge rate 2005; Masterson and others, 2009). All the water that flows of 27 in/yr plus recharge from wastewater plus inflow to the through the aquifer and discharges to ponds, streams, coastal aquifer from streams) of water recharges the aquifer at the areas, and production wells is derived from aquifer recharge. water table in this area (table 2); most water (about 65 percent) Groundwater flows from regional water-table divides toward discharges at the coast, and about 28 percent discharges into natural discharge boundaries at streams and coastal water streams. A total of about 24.9 Mgal/d, or about 7 percent, of bodies; some water flows through ponds before discharging, water in the aquifer is withdrawn for water supply (table 2). and some water is removed from the system for water supply. Most pumped water is returned to the hydrologic system as Model-calculated water budgets indicate that, for 2005 wastewater return flow. conditions, approximately 297.3 million gallons per day (Mgal/d) of water (from an average recharge rate of 27 in/yr plus recharge from wastewater) recharges the aquifer system Methods of Investigation in the Plymouth-Carver region (table 1). About 70 percent (209.7 Mgal/d) of this water moves through the aquifer, Previously published groundwater flow models of three discharges to streams, and then flows to the coast. The regional aquifers in southeastern Massachusetts (fig. 1) were remaining 30 percent is distributed into two categories: water used in this study to determine the responses of streams at that enters the aquifer as recharge then discharges directly to various scales (from an individual stream cell to the scale coastal areas (25 percent or 73.4 Mgal/d) and water that is of a subbasin) and ponds to withdrawals and wastewater withdrawn at production wells (5 percent or 14.4 Mgal/d). return flows. The previously published groundwater flow On Cape Cod, groundwater flows outward from regional models were developed to provide information on regional- groundwater divides toward natural discharge locations scale flow that included changes in groundwater levels, pond at streams, coastal estuaries, and the ocean. Most of the levels, and streamflows in response to changing pumping groundwater flows through shallow sediments and discharges and recharge conditions in southeastern Massachusetts. The to streams and estuaries; groundwater recharging the aquifer purpose and analyses of the previously published groundwater near the central groundwater divides flows deep in the aquifer flow models and the purpose and analyses of the simulations and discharges into the open saltwater bodies (fig. 3). Model- in this study are similar, and therefore the previously calculated water budgets for the combined simulations of published groundwater flow models, with some modification the western and eastern Cape indicate that, for conditions as (appendix 1), were deemed appropriate for this study.
Table 1. Simulated hydrologic budget for predevelopment and for pumping only and pumping with wastewater return flow conditions from 2000 through 2005 in the Plymouth-Carver aquifer system in southeastern Massachusetts.
[Modified from Masterson and others (2009, table 2). Mgal/d, million gallons per day; NA, not applicable]
Predevelopment 2005 Flow, Percentage Flow, Percentage in Mgal/d of total in Mgal/d of total Inflow Recharge 289.9 100 289.9 98 Wastewater 0 0 7.4 2 Total 289.9 100 297.3 100 Outflow Streams 216.8 75 209.7 70 Coast 73.4 25 73.4 25 Pumping wells 0 0 14.4 5 Total 290.2 100 297.5 100
Numerical model error 0.3 NA 0.2 NA Methods of Investigation 7
Table 2. Simulated hydrologic budget for predevelopment and for pumping only and pumping with wastewater return flow conditions in 2003 in the western Cape (Sagamore flow lens) and eastern Cape (Monomoy flow lens) models of Cape Cod in southeastern Massachusetts.
[Modified from Walter and Whealan (2005, table 1). Mgal/d, million gallons per day]
Predevelopment 2003 Flow, Percentage Flow, Percentage in Mgal/d of total in Mgal/d of total Sagamore flow lens Inflow Recharge 252.1 99 252.1 94 Wastewater 0 0 14.8 5 Streams 2.3 1 2.3 1 Total 254.3 269.2 Outflow Estuaries 105.8 42 105.4 39 Coast 71.6 28 72.3 27 Streams 77 30 74.2 28 Pumping wells 0 0 17.3 7 Total 254.4 269.2 Monomoy flow lens Inflow Recharge 103.2 99 103.2 93 Wastewater 0 0 6.5 6 Streams 0.9 1 0.9 1 Total 104.1 110.6 Outflow Estuaries 46 44 46.4 42 Coast 39 37 39 35 Streams 19.1 18 17.6 16 Pumping wells 0 0 7.6 7 Total 104.1 110.6
Groundwater Flow Models to calibrate the models, and the steady-state and transient calibration procedures and results are provided in the original The development and calibration of the groundwater documentation. Descriptions of the simulation of streams, models for the Plymouth-Carver region and western and ponds, and water use (withdrawals and wastewater return eastern Cape Cod are fully documented in Masterson and flows) pertinent to this study are provided in this section. others (2009), Walter and Whealan (2005), and Walter and In both models, streams were simulated by using Masterson (2011). The steady-state and transient versions the Streamflow-Routing (STR) package for the USGS of the Plymouth-Carver model were used in this study three-dimensional finite-difference groundwater model without additional modification. In contrast, a sequence of MODFLOW (Prudic, 1989); the STR package allows for steady-state and transient models covering Cape Cod were groundwater discharge to the stream (gaining streams) as developed for previous investigations (Walter and Whealan, well as infiltration from the stream into the aquifer (losing 2005; Walter and Masterson, 2011), and updates to these streams) to be modeled. Representing streams by using models were required for the transient analysis (appendix 1). the STR package allows for simulation of potential losing Detailed descriptions of the spatial discretization and layering conditions, particularly downgradient of pond outlets and of the models, hydrologic boundaries, hydraulic properties near production wells. In the STR package, each stream of the aquifers, hydrologic stresses, observation data used is represented by segment and reach values. A segment is 8 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass. a group of stream-reach cells, and a reach is an individual uncertainty in the simulation results. This issue is discussed in model cell that represents a portion of a stream. For clarity, a greater detail in the “Limitations” section of this report. reach is referred to as a stream model cell for the rest of the The locations and rates used in this study for pumping report. In the model, the streams are divided into segments and wastewater return flow are the same as those used in the that are numbered from 1, located in the upland area, to the original studies of Masterson and others (2009) and Walter total number of segments located in the lowland area. Each and Whealan (2005). Steady-state simulations were used to segment consists of two or more stream model cells that are evaluate long-term average effects of pumping and wastewater numbered from 1 at the upstream end to the total number return flows on water levels and streamflows, and transient of cells at the downstream end. Stream segment and reach simulations were used to evaluate average monthly effects. information is also included in the shapefiles and spreadsheet The current pumping and wastewater return flow conditions files in appendixes 2 and 3 so that simulated changes in flow were defined as 2000 through 2005 for the Plymouth-Carver along a particular stream can be identified; simulations provide model (referred to as 2005 in this report) and 2003 for the streamflow changes for each stream model cell. Streams in western and eastern Cape Cod models. Although these time the study area generally show gaining characteristics (where periods do not exactly coincide, the difference was considered streamflow increased with distance downstream). However, minor and was deemed acceptable for this study. in some locations, streams show losing characteristics (where Production wells, which are represented by a specified- streamflow decreased with distance downstream). Losing flux boundary condition, were simulated by the Well characteristics are typically associated with pond outlets or (WEL) package of MODFLOW (McDonald and Harbaugh, local areas affected by large groundwater withdrawals. 1988). In the Plymouth-Carver region, production wells A total of 45, 13, and 3 named streams were simulated in represented in the model were mostly for public supply, the Plymouth-Carver, western Cape, and eastern Cape models, but several permitted commercial and irrigation wells were respectively. Additionally, several unnamed streams were also simulated. Eighty-eight wells from communities in the simulated in each model. In total, streamflow was simulated area were represented in the Plymouth-Carver model (fig. 2; for 3548, 442, and 178 stream model cells in the Plymouth- Masterson and others, 2009, table 1–4b); of these wells, Carver, western Cape, and eastern Cape models, respectively. 28 were inactive (nonpumping) in 2005. Average monthly Some streams of greater length were simulated by using pumping rates ranged from 0.01 to 1.16 million gallons per several segments. The total number of ponds simulated was day (Mgal/d). Commercial, irrigation, and private (domestic) 391, of which 218, 101, and 72 were in the Plymouth-Carver, well withdrawals represented only a small percentage of the western Cape, and eastern Cape models, respectively. These total pumping in the study area, and most of these smaller included ponds with inflowing or outflowing streams as well withdrawals were not represented in the Plymouth-Carver as kettle ponds that were not directly connected to streams. model. For 2005 conditions, the combined pumping from Ponds were represented in the groundwater models as areas these nonmunicipal sources accounted for less than 10 percent of high hydraulic conductivity (Masterson and others, 2009; of the total withdrawals (Masterson and others, 2009). In Walter and Whealan, 2005; Walter and Masterson, 2011). addition, water withdrawn from these wells typically is There were many instances where a simulated stream received returned to the aquifer as increased recharge at or near the outflow from a headwater pond. That is, once water in the well; consequently, the net withdrawal of water is near zero. pond (surface water that originated as groundwater that seeped In the western and eastern Cape Cod models, production wells into the pond from the underlying sediments) reached a certain represented in the models also were mostly for public supply elevation, water flowed out of the pond and into the stream. (Walter and Whealan, 2005, table 1–3). In 2003, communities Although there are many locations in southeastern in the modeled area operated 184 production wells, of which Massachusetts where a stream receives outflow from a 117 were in the western Cape and 67 were in the eastern Cape pond, some locations, such as the Silver Lake/Jones River (fig. 3); of these wells, 30 were inactive in 2003. Falmouth system in the Plymouth-Carver model (fig. 2), involve water also withdrew drinking water directly from Long Pond, the withdrawals and transfers and are more complex than most only direct surface-water withdrawal in the Cape Cod models. other pond and stream systems. In the original study, the water Average pumping rates ranged from about 0.001 to 2.5 Mgal/d withdrawals and transfers at this location were represented in 2003 (Walter and Whealan, 2005, table 1–3). As with the in a simplified manner as a surface-water withdrawal from Plymouth-Carver model, smaller nonmunicipal withdrawals Silver Lake. In addition, simulations were conducted with accounted for only a small proportion of total withdrawals and an approximate pond outlet elevation based on a topographic were not represented in the Cape Cod models. Withdrawals map. This simplified representation of the Silver Lake/Jones from surface water were represented as a simulated production River system in the Plymouth-Carver model was reasonable well located within the area of the pond. For both studies, given the regional nature of the original study. However, for pumping rates were compiled from Massachusetts Department the study detailed in this report, in which determination of of Environmental Protection records. streamflow alteration downstream from the pond is a stated In addition to recharge from precipitation, the portion objective, the simplified approach used in the regional model of water pumped for public supply that is returned to the to represent the Silver Lake/Jones River system produces aquifer through domestic septic systems and centralized Methods of Investigation 9 wastewater treatment facilities is a source of recharge to the bog areas, where the wells capture water that otherwise aquifer systems in southeastern Massachusetts. Most of the would have discharged naturally to the bogs. Therefore, for groundwater withdrawn for public supply is returned to the the purpose of the regional Plymouth-Carver model analysis aquifer as wastewater return flow. The consumptive loss rate it was assumed that the water use related to cranberry bog in residential areas was assumed to be about 15 percent of operations was accounted for in the simulated recharge rate. total pumping; thus, 85 percent of the total public supply was The simulated recharge rate for cranberry bogs was similar assumed to be returned to the aquifer as enhanced recharge to that of wetlands; however, it was assumed that the bogs (by means of the Recharge package of MODFLOW; behave more like ponds than wetlands during the month of McDonald and Harbaugh, 1988) in residential areas. In October when the bogs are typically flooded for harvesting, southeastern Massachusetts, residential areas are served resulting in an additional 2 in/yr of recharge. Therefore, by varying combinations of water-supply distribution and the simulated recharge rate for cranberry bogs was 10 in/yr wastewater disposal systems. Examples include areas with compared with the 8 in/yr specified for wetlands (Masterson public water supply and septic systems, areas with both public and others, 2009). The determination of site-specific cranberry water supply and sewers, and areas with both private water bog irrigation effects on individual streams and ponds would supply (domestic wells) and septic systems. Wastewater return have required detailed local-scale analyses of the water-use flows associated with public supply withdrawals (the first operations for individual bogs and thus was not considered in two combinations) are represented in the groundwater flow the regional Plymouth-Carver model analysis. models; these return flows represent a net import of water to a residential area. Distributions of septic systems and locations of municipal treatment facilities used for wastewater disposal Development of Contributing Areas in the Plymouth-Carver and Cape Cod models are shown in figures 2 and 3, respectively. The nonsewered residential The procedure used in this study to determine areas, where water from public supply withdrawals is returned contributing areas (including groundwater subbasins and to the aquifer through onsite septic systems, are widespread in hydrologic units) was based on a procedure documented southeastern Massachusetts (figs. 2 and 3) and represent areas in Barlow (1997) for delineating contributing areas for with relatively low rates of enhanced recharge. In the area production wells on Cape Cod, which was subsequently used of the Plymouth-Carver model, there were four centralized by Masterson and others (1998) and Masterson and Walter wastewater treatment facilities in operation during 2005, in (2000) for similar analyses. The analysis of Masterson and Kingston, Plymouth (2 sites), and Wareham (fig. 2). In the Walter (2000) also included the delineation of groundwater areas of the Cape Cod models, there were five centralized contributing areas to other discharge locations, such as ponds, wastewater treatment facilities, in Barnstable, Chatham, streams, and coastal areas. To determine contributing areas, Falmouth, Orleans, and on the Massachusetts Military the MODPATH particle-tracking model developed by Pollock Reservation (fig. 3). These facilities are relatively large point (1994), which uses the heads and intercell flow rates (the sources of wastewater return flow. Wastewater disposal rates flow rate at the face of each cell in the model) calculated were compiled from data provided by treatment facilities. by the MODFLOW–2000 (Harbaugh and others, 2000) or Overall, for 2005 average conditions, about 3 percent of MODFLOW–2005 (Harbaugh, 2005) flow models, was used groundwater discharge to streams in the Plymouth-Carver to determine water particle pathlines and velocities. Starting model area is from wastewater return flow to the aquifer. locations of particles must be specified to initiate a particle- Wastewater return flow as an additional source of aquifer tracking analysis. Particles may be tracked either forward recharge can have locally important effects on alteration of (from the water table to a discharge location) or backward streamflow and pond water levels (see “Simulated Responses (from a discharge location to the water table), but forward of Streamflows and Pond Levels to Pumping and Wastewater tracking has proven to be more reliable for delineating Return Flows” section). contributing areas (Barlow, 1997). Masterson and others Cranberry bog operations are prevalent in the Plymouth- (1998) used MODPATH to track particles forward through Carver region and less common on Cape Cod. They the simulated flow system until they reached the locations of encompass about 16 mi2 (10,000 acres), or about 6 percent production wells (discharge areas). In Masterson and others of the total active Plymouth-Carver model area. The 2005 (1998), the contributing area to the selected well was defined annual average water use for the bog operations was about by the area at the water table from which the particles that 80 Mgal/d (James McLaughlin, Massachusetts Department of were captured by the well originated. Pollock (1994), Barlow Environmental Protection, written commun., 2006). However, (1997), Franke and others (1998), Masterson and others unlike water pumped for public supply, most of this water (1998), and Masterson and Walter (2000) provide detailed originates from the localized manipulation of streamflow in information on the use of particle tracking for the delineation surface-water bodies, such as the diversion and impoundment of areas contributing groundwater to discharge locations. of streamflow, rather than from the pumping and exporting of In this study, the steady-state models of the Plymouth- water for use away from the pumping source. Groundwater Carver region and western and eastern Cape Cod were used to is typically pumped for cranberry irrigation adjacent to the track particles forward, from the water table to the discharge 10 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass. location, in the direction of groundwater flow. In the MOD- directly to the coast; these areas are extensive in southeastern PATH simulations, a single instantaneous release was speci- Massachusetts (figs. 5 through 7). fied of a two-dimensional four-by-four array of particles that were placed at the top face in each grid cell in the model, and Table 3. Stream identification, landscape characteristics, and endpoints were recorded for the particles that terminated in simulated average streamflows for hydrologic units and subbasins a specific zone. “Zone” is a term used by MODPATH that in in southeastern Massachusetts. this analysis refers to the stream subsections or lengths along streams between outlet points. Ponds were included in these [Available separately at http://dx.doi.org/10.3133/sir20155168] subsections if they were connected to a stream at its head- waters (for example, Halfway Pond and Little Herring Pond Table 4. Percent impervious cover and long-term average [fig. 2] in the Plymouth-Carver model) or if they were directly streamflow for hydrologic units in southeastern Massachusetts. connected to the stream and therefore considered to be part of the stream network (for example, Glen Charlie Pond and [Available separately at http://dx.doi.org/10.3133/sir20155168] Great Herring Pond [fig. 2] in the Plymouth-Carver model). In the MODPATH analysis, all the stream cells and surface- The outlet points were positioned to provide hydrologic water-connected pond cells in a zone between outlet points units of similar size to the topographically determined areas were assigned the same identification number to determine in Weiskel and others (2010), which averaged 5.3 mi2. the groundwater contributing area to that stream subsection. Based on an average recharge rate of 27 in/yr (Walter and Ponds not in direct surface-water contact with a stream were Whealan, 2005; Masterson and others, 2009) applied to not included in a respective zone. The groundwater contribut- the 400-by-400-foot (ft) model cells over a 5.3-mi2 area, ing areas delineated in this study are those expected to occur an increase in simulated streamflow of about 10.4 cubic under steady-state, predevelopment conditions. feet per second (ft3/s) was used to identify the length of the Groundwater contributing areas were calculated to stream subsection between outlet points that corresponded evaluate streamflow depletion at the outlets of groundwater to the contributing area of 5.3 mi2. This streamflow criterion subbasins and determine selected landscape characteristics was used as a general guideline to divide simulated streams within groundwater subbasins (see the following discussion of with various numbers of tributaries into subsections so that subbasins and hydrologic units). Determination of streamflow locations of outlet points could be identified. Simulated alteration and landscape characteristics at the subbasin scale long-term average streamflows at the downstream ends of provides information comparable to that in Weiskel and others the subsections (or the outlet points of the hydrologic units) (2010). Although the methods used in this study to delineate ranged from 0 to 17.3 ft3/s (tables 3 and 4). Most of the contributing areas to streams differed from those described in streamflows at the lower end of this range were in shorter Weiskel and others (2010), the same terminology was used for streams that drained small contributing areas (for example, consistency (fig. 4). A subbasin is defined as the total upstream hydrologic unit HU–24 and subbasin SB–24; figs. 5 and 6; drainage area (or watershed) that drains to a selected location tables 3 and 4). The streamflow of 0 ft3/s was in subbasin along a stream (referred to as an outlet point in this report); SB–23, which is discussed in greater detail in the “Alteration if there are multiple outlet points selected along a stream, the of Streamflows at Subbasin Outlets” section of this report. contributing area of the uppermost outlet point is referred to as a headwater subbasin. A hydrologic unit is defined as the local Most of the streamflows at the higher end of this range were area that drains to a stream between two outlet points. For the associated with long streams that drained large contributing upstreammost outlet point on streams with multiple points and areas with relatively extensive stream networks that included for streams with a single outlet point, hydrologic units and multiple tributaries. Multiple outlet points were used to subbasins are coincident (fig. 4). delineate hydrologic units on these streams (for example, This analysis produced 78 contributing areas in subbasin SB–8, which consisted of hydrologic units HU–2, southeastern Massachusetts (figs. 5 through 7; tables 3 and 4). HU–3, HU–4, HU–5, HU–6, HU–7, and HU–8; fig. 7; Of the 78 hydrologic units in the study area (fig. 5), 61 are tables 3 and 4). One of the various exceptions to the simple also headwater subbasins (fig. 6). Although differentiated accumulation of streamflow from groundwater contributing in figures 6 and 7 to more clearly show the extent of each areas is the Billington Sea/Town Brook system (fig. 2), which subbasin, several headwater subbasins are nested within larger was represented in the Plymouth-Carver model by a headwater subbasins that correspond to downstream outlet points (fig. 7). pond with a single outflow stream (hydrologic unit HU–32 For example, hydrologic units HU–78 and HU–79 (fig. 5) are and subbasin SB–32). The simulated long-term average combined to form subbasin SB–79 (fig. 7). The remaining predevelopment outflow from Billington Sea to Town Brook 17 hydrologic units on the large streams compose the local was 12.4 ft3/s (already greater than the streamflow criterion drainage areas to outlet points downstream from the headwater of 10.4 ft3/s), and the streamflow at the outlet point of Town areas. Precipitation that falls on the land surface outside of Brook was 17.3 ft3/s. This example shows the effect that pond hydrologic unit and subbasin areas ultimately discharges outflows can have on simulated streamflows. Methods of Investigation 11
A. Hydrologic Units (HU)
HU–1 Outlet point of the hydrologic unit HU–3 Outlet point of furthest upstream HU–3
HU–2 Outlet point of HU–2 EXPLANATION Basin boundary Hydrologic unit or subbasin boundary HU–4 Small stream Medium stream Large stream Outlet point of HU–4
B. Nested or "stacked" subbasins (SB) SB–1 Outlet point of SB–1, SB–3 a headwater subbasin Outlet point of first in the sequence SB–3, downstream a headwater subbasin third in the sequence downstream SB–2 Outlet point of SB–2 (area of SB–2 includes the area of SB–1)
SB–4
Outlet point of SB–4 (area of SB–4 includes the area of SB–3 and the area of SB–2, which, in turn, includes the area of SB–1)
Figure 4. Generalized groundwater contributing areas in southeastern Massachusetts defined as A, hydrologic units and B, subbasins for simulating responses of streams and ponds to groundwater withdrawals and wastewater return flows. A hydrologic unit is defined as the local area that drains to a particular stream or set of small streams between two outlet points. A subbasin is defined as the entire upstream area that drains to an outlet point; the area of subbasins increases in the downstream direction. Hydrologic units of southeastern Massachusetts are shown in figure 5; headwater subbasins are shown in figure 6, and other subbasins are shown in figure 7. Modified from Weiskel and others (2010). 12 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass. 10 MILES 70° 10 KILOMETERS 77 Hydrologic units 5 76 74 5 79 78 75 73 0 0 67 Eastern Cape (Monomoy) model 66 65 EXPLANATION unit was based Pond Stream number —Prefix HU– omitted for clarity (“hu_id” in tables and GIS shapefiles) Outlet point of hydrologic unit Simulated zone on which the hydrologic Hydrologic unit area and identification 78 63 64 68 69 62 61 Western Cape (Sagamore) model Cape Western 60 58 59 70 57 56 71 55 24 72 25 54 52 26 70°33' 27 48 53 28 23 22 49 50 51 21 30 Plymouth-Carver model 18 17 20 31 29 16 19 15 42 14 45 43 33 41 6 13 32 11 40 44 39 12 9 2 10 37 46 38 7 8 3 36 34 5 35 4 47 imulated hydrologic units for streams and surface-water-connected ponds in the Plymouth-Carver, western Cape, and eastern Cape ponds in the Plymouth-Carver, imulated hydrologic units for streams and surface-water-connected S
Base from U.S. Geological Survey and Massachusetts Office of Geographic Information data, 2001 Massachusetts State Plane Coordinate System, mainland zone 19, North American Datum 1983, 1:25,000 42° 41°45' Figure 5. model areas in southeastern Massachusetts. Methods of Investigation 13 10 MILES 70° 77 5 76 74 Headwater subbasins 78 73 0 0 5 10 KILOMETERS 67 Eastern Cape (Monomoy) model 66 65 EXPLANATION Pond Stream number —Prefix SB– omitted for clarity (“sb_id” in table and GIS shapefiles) subbasin was based —Ponds and streams not within a headwater subbasin are shaded with pale blues Headwater subbasin area and identification Simulated zone on which the headwater Outlet point of headwater subbasin 63 28 64 68 69 62 61 Western Cape (Sagamore) model Cape Western 58 59 70 56 55 24 72 25 54 52 70°33' 26 27 48 28 23 22 49 50 51 21 Plymouth-Carver model 17 20 31 29 16 19 15 14 42 45 43 33 41 6 32 13 11 44 40 9 2 10 46 38 34 35 47 imulated headwater subbasins for streams and surface-water-connected ponds in the Plymouth-Carver, western Cape, and eastern ponds in the Plymouth-Carver, S imulated headwater subbasins for streams and surface-water-connected
Base from U.S. Geological Survey and Massachusetts Office of Geographic Information data, 2001 Massachusetts State Plane Coordinate System, mainland zone 19, North American Datum 1983, 1:25,000 42° 41°45' Figure 6. Cape model areas in southeastern Massachusetts. Headwater subbasins and hydrologic units are coincident. Where present, downstr eam subbasins that are shown in figure 7 omitted for clarity. 14 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass. 10 MILES Subbasins 70° 10 KILOMETERS 5 5 75 79 0 0 Eastern Cape (Monomoy) model EXPLANATION Stream Pond Outlet point of subbasin Subbasin area and identification number —Prefix SB– omitted for clarity (“sb_id” in table and GIS shapefiles) Simulated zone on which the subbasin was based —Ponds and streams in a headwater subbasin are shaded with pale blues 4 Western Cape (Sagamore) model Cape Western 60 57 71 70°33' 53 30 Plymouth-Carver model 18 39 12 37 7 8 3 36 5 4 imulated subbasins for streams and surface-water-connected ponds in the Plymouth-Carver, western Cape, and eastern Cape model areas in ponds in the Plymouth-Carver, imulated subbasins for streams and surface-water-connected S
Base from U.S. Geological Survey and Massachusetts Office of Geographic Information data, 2001 Massachusetts State Plane Coordinate System, mainland zone 19, North American Datum 1983, 1:25,000 42° 41°45' Figure 7. Subbasins SB–3, SB–4, SB–5, SB–7, and SB–8 are shown in a southeastern Massachusetts. Headwater subbasins that are shown in figure 6 omitted for clarity. stacked sequence, in which subbasin SB–3 is on top because it furthest upstream and SB–8 at the bottom becaus e downstream. Subbasin subbasins SB–36, SB–37, and SB–39 are shown in a stacked sequence, which subbasin SB–36 is SB–8 includes the areas of SB–3, SB–4, SB–5, and SB–7. Similarly, SB–39 includes the areas of SB–36 and SB–37. is furthest downstream. Subbasin at the bottom because it subbasin SB–39 is upstream and because it is furthest on top Simulated Responses of Streamflows and Pond Levels to Pumping and Wastewater Return Flows 15 Simulated Responses of Streamflows Streams in southeastern Massachusetts are relatively small compared with those in the rest of the Commonwealth. and Pond Levels to Pumping and Maximum long-term average predevelopment streamflows ranged from 13.1 ft3/s in the eastern Cape model to 68.8 ft3/s Wastewater Return Flows in the Plymouth-Carver model (table 5). The simulated responses of streamflows and pond levels to pumping and wastewater return flows varied by location Alteration of Streamflows at Subbasin Outlets and included no change in areas minimally affected by water use, decreases in areas affected more by pumping than by For consistency with Weiskel and others (2010), wastewater return flows, or increases in areas affected more streamflow alterations were computed at the outlets of the by wastewater return flows than by pumping. Groundwater groundwater subbasins. Long-term average (steady-state) and models were used to simulate these responses because the average monthly conditions are detailed in this section. models simultaneously accounted for the simulated locations of streams, ponds, production wells, and return flows, the Long-Term Average Conditions spatial variability of hydraulic properties of the aquifer both Streamflow results are summarized in the following vertically by model layer and horizontally, the long-term sections for long-term average (steady-state) simulations for average and the average monthly recharge rates to the aquifer, predevelopment, pumping only, and pumping with wastewater and pumping and wastewater return flow rates. Uncertainties return flow conditions for southeastern Massachusetts at the inherent in using groundwater models to address complex outlet point of each subbasin (fig. 8). To compare results groundwater/surface-water interactions are described in the among subbasins, steady-state streamflows from each subbasin “Limitations” section of this report. were also normalized by subbasin area to yield absolute To identify which stream cells and pond locations could streamflows in cubic feet per second per square mile (ft3/s/mi2) be affected under pumping only and pumping with wastewa- (fig. 9). The relative difference in streamflows due to pumping ter return flow conditions, changes in simulated streamflows only and pumping with wastewater return flow conditions in and pond levels were determined by subtracting the simulated comparison to predevelopment conditions at each subbasin is results of each water use condition from the predevelopment also shown. condition. Simulated streamflows and changes in streamflow of less than 0.1 ft3/s were considered to be negligible and within the margin of model error. Therefore, results shown Predevelopment Conditions in the shapefiles and spreadsheet tables and described below The medians and averages of normalized predevelop- reflect streamflows and changes in streamflows of 0.1 ft3/s or ment streamflows at subbasin outlets, respectively, were greater. Changes in streamflows of less than 0.1 ft3/s were set 1.6 cubic feet per second per square mile (ft3/s/mi2) and equal to zero in these files. In addition to calculating absolute 1.6 ft3/s/mi2 for the Plymouth-Carver model, 1.8 and changes, streamflow alterations were also calculated as per- 1.7 ft3/s/mi2 for the western Cape model, and 1.8 and centages to more clearly show the relative effects of pumping 1.6 ft3/s/mi2 for the eastern Cape model. The medians and and wastewater return flows on streamflow. For example, averages of the nonnormalized streamflows were 7.8 and streamflow in a stream cell in Indian Brook in Plymouth 6.9 ft3/s for the Plymouth-Carver model, 4.2 and 4.9 ft3/s for (fig. 2) was 0.5 ft3/s under predevelopment conditions and the western Cape model, and 3.8 and 4.3 ft3/s for the eastern decreased 0.5 ft3/s under pumping only conditions, which cor- Cape model. The Plymouth-Carver region tended to have responds to a decrease of 100 percent (stream cell went dry), streams of longer length than streams on Cape Cod. For most whereas streamflow in a stream cell in the Weweantic River of the subbasins shown in figure 9, simulated streamflows nor- (fig. 2) was 28.7 ft3/s under predevelopment conditions and malized by subbasin area were about 2 ft3/s/mi2 or less. How- decreased by 1.1 ft3/s under pumping only conditions, which ever, normalized streamflows in subbasin SB–19 (unnamed corresponds to a decrease of only 4 percent, even though the tributary to Muddy Cove, Plymouth-Carver model) were about absolute magnitude of streamflow depletion in the Weweantic 4.3 ft3/s/mi2. The larger normalized streamflows likely are due River was greater than in Indian Brook. to the complicated hydrology in the headwater area of For the transient analysis of streamflow and pond-level subbasin SB–19 where it borders subbasin SB–20 (Gibbs alterations under average monthly conditions, simulated Brook in the Plymouth-Carver model). The local-scale com- changes for August are highlighted in the report as an example plexities of the groundwater/surface-water interactions in this of monthly results. Weiskel and others (2010) found that the area may not be well represented at the scale of the regional greatest degree of monthly streamflow alteration occurred in model, and thus the simulated streamflows and ultimately the August, and Armstrong and others (2011) used the percent resulting area for subbasin SB–19 may not be well represented alteration of August median streamflows in their analysis of by results of the regional model, leading to an anomalously the effects of withdrawals on fish assemblages. Simulation high normalized streamflow. The implications of local effects results for all streams and ponds for all months and for long- within a regional groundwater model are discussed in greater term average conditions are contained in appendix 2. detail in the “Limitations” section of this report. 16 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass.
Table 5. Summary of maximum simulated streamflows and the percentages of stream cells with streamflows within specific ranges under predevelopment conditions for long-term average and monthly simulations of the Plymouth-Carver, western Cape, and eastern Cape models in southeastern Massachusetts.
[ft3/s, cubic foot per second; >, greater than; <, less than; ≥, greater than or equal to]
Maximum pre- Percentage of Percentage Percentage of Percentage of Percentage of Percentage of Percentage development stream cells of stream stream cells stream cells stream cells stream cells of stream Simulation streamflow in that were dry cells where where flow where flow where flow where flow cells where period a stream cell, (no simulated flow was >0 was ≥0.1 ft3/s was ≥1.0 ft3/s was ≥5.0 ft3/s was ≥20.0 ft3/s flow was in ft3/s flow in the cell) but <0.1 ft3/s but <1.0 ft3/s but <5.0 ft3/s but <20.0 ft3/s but <40.0 ft3/s ≥40.0 ft3/s Plymouth-Carver model January 78.1 17 3 24 26 19 6 5 February 82.1 17 3 23 26 20 6 5 March 87.4 16 3 23 26 20 6 6 April 84.8 16 3 23 27 20 6 5 May 77.4 17 3 24 26 19 6 5 June 67.7 17 5 25 26 18 6 3 July 54.6 19 5 26 25 18 5 2 August 50.3 20 6 25 24 18 5 2 September 50.6 20 5 26 24 18 5 2 October 51.7 21 5 25 24 18 5 2 November 62.9 20 4 24 25 18 6 3 December 73.6 18 4 24 25 19 5 5 Steady state 68.8 18 4 25 25 18 6 4 Western Cape model January 18.8 10 2 21 36 31 0 0 February 20.2 8 2 20 37 32 0 0 March 21.7 7 1 19 39 33 1 0 April 22.6 6 1 19 39 33 2 0 May 21.4 6 2 19 40 33 1 0 June 19.4 6 3 19 41 31 0 0 July 17.0 7 2 25 38 27 0 0 August 16.0 9 5 26 34 25 0 0 September 15.4 12 3 31 31 23 0 0 October 15.5 12 4 28 32 24 0 0 November 16.0 12 3 23 35 26 0 0 December 17.2 12 3 22 35 29 0 0 Steady state 18.4 8 2 21 38 30 0 0 Eastern Cape model January 13.7 17 1 19 34 29 0 0 February 14.6 17 1 14 39 29 0 0 March 15.6 16 1 12 41 30 0 0 April 15.9 16 1 12 40 31 0 0 May 14.8 17 1 12 40 30 0 0 June 12.9 18 1 12 43 26 0 0 July 9.9 18 1 28 38 16 0 0 August 8.3 20 2 35 30 13 0 0 September 8.0 22 7 28 30 13 0 0 October 8.7 22 3 31 28 15 0 0 November 11.0 21 6 26 20 26 0 0 December 12.6 17 1 33 20 29 0 0 Steady state 13.1 16 1 15 39 29 0 0 Simulated Responses of Streamflows and Pond Levels to Pumping and Wastewater Return Flows 17 9 7 8 7 7 7 6 7 5 7 4 7 Eastern Cape 3 7 2 7 1 7 0 7 9 6 8 6 7 6 6 6 5 6 4 6 3 6 2 6 1 6 0 6 9 5 8 5 7 Western Cape 5 6 5 5 5 4 5 3 5 2 5 1 5 0 5 9 4 8 4 7 4 6 Predevelopment Pumping only Pumping with wastewater return flow EXPLANATION 4 5 Steady-state streamflow in cubic feet per second for each condition 4 4 4 3 4 2 4 1 4 0 4 9 3 Subbasin 8 3 7 3 6 3 5 3 4 3 3 3 2 3 1 3 0 3 9 2 8 2 7 2 6 2 5 2 4 2 3 2 2 2 1 Plymouth-Carver 2 0 2 9 1 8 1 7 1 6 1 5 1 4 1 3 1 2 1 1 1 0 1 9 8 7 6 5 4 imulated long-term average (steady-state) streamflows for predevelopment, pumping only, and pumping with wastewater return flow conditions for each imulated long-term average (steady-state) streamflows for predevelopment, pumping only, 3 S 2
0
70 6 0 5 0 4 0 3 0 2 0 1 0 Steady-state streamflow, in cubic feet per second second per feet cubic in streamflow, Steady-state Figure 8. western Cape, and eastern Cape model areas in southeastern Massachusetts. Subbasin prefix SB– omitted from subbasin identification subbasin in the Plymouth-Carver, numbers for clarity. 18 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass. 9 7 8 7 7 7 6 7 5 7 4 7 Eastern Cape 3 7 2 7 1 7 0 7 9 6 8 6 7 6 6 6 5 6 4 6 3 6 2 6 1 6 0 6 9 5 8 5 7 Western Cape 5 6 5 5 5 4 5 3 5 2 5 1 5 0 5 9 4 8 4 7 4 EXPLANATION 6 4 5 4 4 4 3 4 2 4 1 4 Predevelopment Pumping only Pumping with wastewater return flow 0 4 Steady-state streamflow in cubic feet per second per square mile for each condition 9 3 8 3 7 3 Subbasin 6 3 5 3 4 3 3 3 2 3 1 3 0 3 9 2 8 2 7 2 6 2 5 2 4 2 3 2 2 2 1 Plymouth-Carver 2 0 2 9 1 8 1 7 1 6 1 5 1 4 1 3 1 2 1 1 1 0 1 9 8 7 6 5 imulated long-term average (steady-state) streamflows normalized by subbasin area for predevelopment, pumping only, and pumping with wastewater imulated long-term average (steady-state) streamflows normalized by subbasin area for predevelopment, pumping only, 4 S 3
2
5 4 3 2 1 0 Steady-state streamflow, in cubic feet per second per square mile mile square per second per feet cubic in streamflow, Steady-state Figure 9. western Cape, and eastern Cape model areas in southeastern Massachusetts. Subbasins SB–19, SB–23, return flow conditions for subbasins in the Plymouth-Carver, SB–78 are discussed in this report. Subbasin prefix SB– omitted from subbasin identification numbers for clarity. Simulated Responses of Streamflows and Pond Levels to Pumping and Wastewater Return Flows 19
Pumping Only Conditions –3.1 percent for the western Cape, and –4.1 percent for the eastern Cape, and alterations were near median values Simulated percentage alterations to long-term average for most of the subbasins in the study area (for example, streamflows due to pumping only are shown by subbasin alterations at 65 of 78 subbasins were within 10 percent in figure 10A. The largest depletions by model area were 57.4 percent for subbasin SB–26 (unnamed tributary to of predevelopment streamflows). As shown in figure 10, Salt Pond, Plymouth-Carver model; fig. 2), 40.5 percent for streamflow depletions at subbasin outlets were more common subbasin SB–66 (Hawes Run, western Cape model; fig. 3), than augmentations. and 48.6 percent for subbasin SB–77 (Red River, eastern Cape model; fig. 3). Median streamflow alterations for the subbasins Average Monthly Conditions in the model areas were –5.8 percent for the Plymouth-Carver, –8.2 percent for the western Cape, and –8.8 percent for the This section describes simulated streamflow results for eastern Cape model areas. average monthly conditions. The months of January, April, Streamflows from subbasins SB–23 (Herring River, August, and October were the focus of the study of Weiskel Plymouth-Carver model) and SB–78 (Stony Brook, eastern and others (2010); summary results for all months are Cape model) were dry under predevelopment, pumping discussed further in the following sections (tables 5 and 6). only, and pumping with wastewater return flow conditions Complete simulated streamflows results (all months at all (fig. 8). Subbasin SB–23 contains Great Herring Pond, which streams in the model areas) are included in appendixes 2 outflows to the Herring River. Under long-term average and 3. predevelopment conditions, the upstream end of Herring To show the effects of water use during August, which River receives inflow from the pond outlet at Great Herring is the low-streamflow month evaluated in previous studies, Pond, but the simulation results show that flow from Great average August streamflows under predevelopment, pumping Herring Pond into the Herring River subsequently infiltrates only, and pumping with wastewater return flow conditions at into the underlying aquifer, resulting in no-flow conditions at the outlets of the subbasins are shown in figures 11 and 12 in the subbasin outlet point at the Cape Cod Canal. The results a format similar to that used for long-term average conditions for subbasins SB–23 and SB–78 may be an artifact of how (figs. 8 and 9). Overall, simulation results show that August the change in gradient of the stream is represented at the streamflows in nearly all subbasins are affected by water use; discretization of the regional model grid. however, alterations were relatively minor compared with predevelopment streamflows in most locations (“Pumping Pumping With Wastewater Return Flow Conditions With Wastewater Return Flow Conditions” section). Similar to Simulated alterations to long-term average (steady- long-term average conditions, the relative effects of pumping state) streamflows in response to pumping with wastewater and return flows in the subbasins with lower streamflows at return flows by subbasin are shown in figure 10B. The largest outlets typically are larger than in the subbasins with higher depletions by model area were 43.9 percent for subbasin streamflows. The rates of pumping from the aquifer, the rates SB–26 (unnamed tributary to Salt Pond, Plymouth-Carver of return of wastewater to the aquifer as enhanced recharge, model), 22.8 percent for subbasin SB–66 (Hawes Run, the location of these stresses in relation to streams, and aquifer western Cape model), and 37.7 percent for subbasin SB–77 properties can affect the extent of streamflow alteration. (Red River, eastern Cape model). The changes in streamflow for subbasins SB–26 and SB–77 were less than 1 ft3/s, but Predevelopment Conditions the percentage depletions were higher than in other subbasins because of the relatively low predevelopment streamflow Maximum streamflows under predevelopment conditions compared with the change in streamflow. In contrast to for the Plymouth-Carver region for January, April, August, 3 streamflow decreases in response to pumping only, the return and October were 78.1, 84.8, 50.3, and 51.7 ft /s, respectively of wastewater to the aquifer as enhanced recharge can offset (table 5). Streamflows generally were lower for the subbasins depletions due to pumping or even increase water levels and on Cape Cod because streams are smaller there than in the streamflows in certain areas. The largest increases (surcharged Plymouth-Carver region. Maximum streamflows under prede- streamflows) by model area were 5.5 percent for subbasin velopment conditions for the western Cape for January, April, SB–38 (Halls Brook and Tussock Brook combined, Plymouth- August, and October were 18.8, 22.6, 16.0, and 15.5 ft3/s, Carver model), 18.2 percent for subbasin SB–65 (unnamed respectively (table 5). The lowest maximum monthly tributary to Centerville River, western Cape model), and streamflow of 15.4 ft3/s occurred in September. Maximum 1.3 percent for subbasin SB–79 (Stony Brook, eastern Cape streamflows under predevelopment conditions for the eastern model). Increases in streamflows in response to wastewater Cape for January, April, August, and October were 13.7, 15.9, return flows were generally largest in subbasins with a high 8.3, and 8.7 ft3/s, respectively (table 5). The lowest maximum density of septic systems or a centralized wastewater treatment predevelopment streamflow of 8.0 ft3/s occurred in September. facility. Median streamflow alterations for the subbasins in Streamflows tended to be lowest in August, but certain streams the model areas were –2.7 percent for the Plymouth-Carver, showed slightly lower streamflows in other months. 20 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass.
A. Pumping only conditions Eastern Plymouth-Carver Western Cape Cape 0 2 5 8 11 14 17 20 23 26 29 32 35 38 41 44 47 50 53 56 59 62 65 68 71 74 77
-10
Depleted -20
-30
-40
-50
-60 B. Pumping with wastewater return flow conditions 20
Surcharged 10 38 50 56 0 2 5 8 11 14 17 20 23 26 29 32 35 41 44 47 53 59 62 68 71 74 77 65
Alteration of steady-state streamflow from predevelopment conditions, in percent -10
-20 Depleted
-30
-40
-50
-60 Subbasin
Figure 10. Percentage simulated changes in long-term average streamflow at the outlets of subbasins in southeastern Massachusetts from predevelopment conditions for A, pumping only or B, pumping with wastewater return flow conditions at the outlet of each subbasin. Prefix SB– omitted from subbasin identification numbers for clarity. Simulated Responses of Streamflows and Pond Levels to Pumping and Wastewater Return Flows 21 conditions Pond with the town forest with return flow in water level be - ment and pumping tween predevelop - maximum increase Goose Pond Goose Pond Shallow Pond Lake Wequaquet Goose Pond Shallow Pond Silver Lake Shallow Pond Goose Pond Shallow Pond Goose Pond Shallow Pond Goose Pond Lake Wequaquet Goose Pond Lake Wequaquet Goose Pond Lake Wequaquet Goose Pond Lake Wequaquet Goose Pond Lake Wequaquet Goose Pond Shallow Pond Unnamed pond near Shallow Pond 0.4 0.4 0.8 0.9 0.4 0.8 0.5 0.8 0.4 0.8 0.4 0.8 0.4 0.8 0.4 0.8 0.4 0.8 0.4 0.8 0.4 0.8 0.4 0.8 0.5 0.9 in ft Maximum return flow conditions, increase in opment conditions for the tween prede - pumping with velopment and water level be - conditions and pumping maximum de - Pond with the level between crease in water predevelopment with return flow Negro Pond Negro Pond Long Pond Long Pond Negro Pond Long Pond Negro Pond Long Pond Negro Pond Long Pond Negro Pond Long Pond Negro Pond Long Pond Negro Pond Long Pond Negro Pond Long Pond Negro Pond Long Pond Negro Pond Long Pond Negro Pond Long Pond Great South Pond Long Pond in ft -3.5 -3.5 -2.9 -3.5 -2.7 -3.5 -2.7 -3.5 -2.6 -3.5 -2.7 -3.5 -3.2 -3.5 -4.0 -3.5 -4.5 -3.5 -4.3 -3.5 -3.9 -3.5 -3.4 -4.6 -3.1 -3.2 conditions, and pumping Maximum de - level between crease in water predevelopment with return flow Pond with conditions the maximum level between predevelopment and pumping only decrease in water Triangle Pond Triangle Triangle Pond Triangle Long Pond Triangle Pond Triangle Long Pond Triangle Pond Triangle Mary Dunn Pond Triangle Pond Triangle Mary Dunn Pond Triangle Pond Triangle Mary Dunn Pond Triangle Pond Triangle Long Pond Triangle Pond Triangle Long Pond Triangle Pond Triangle Long Pond Triangle Pond Triangle Long Pond Triangle Pond Triangle Long Pond Triangle Pond Triangle Long Pond Great South Pond Long Pond Mary Dunn Pond , 218; western Cape, 101; and eastern 72. ≥, greater than or equal to; ft, foot] in ft -4.2 -4.2 -4.2 -3.2 -4.2 -3.1 -4.2 -3.1 -4.2 -3.3 -4.2 -3.6 -4.3 -4.5 -4.3 -4.9 -4.3 -4.7 -4.3 -4.3 -4.3 -3.9 -4.8 -3.6 -3.3 -3.8 tions, Western Cape model Western Maximum Plymouth-Carver model only condi - water level decrease in development and pumping between pre - 28 28 26 67 24 67 24 66 26 67 26 68 28 68 31 71 34 70 33 70 28 70 28 69 68 67 ≥ 0.1 ft and pumping ponds where Percentage of the difference level between conditions was (increase or de - predevelopment with return flow crease) in water 37 36 35 83 33 81 33 82 35 81 35 82 38 82 40 82 41 85 40 85 38 85 35 84 84 85 between ment and conditions was ≥ 0.1 ft predevelop - ponds where pumping only in water level Percentage of the difference - 61 60 56 68 52 68 52 67 56 68 56 69 62 69 68 72 74 71 73 71 62 71 60 70 69 68 ≥ 0.1 ft and pumping conditions was predevelopment with return flow where the differ decrease) in wa - Number of ponds ence (increase or between level ter - 81 79 77 84 73 82 73 83 76 82 77 83 83 83 88 83 89 86 87 86 83 86 77 85 85 86 ment and the differ Number of conditions was ≥ 0.1 ft predevelop - ponds where pumping only ence in water level between Summary of changes in pond levels under pumping only and with wastewater return flow conditions compared predevel
period Simulation January February March February April March May April June May July June August July September August October September November October December November Steady state December January Steady state Table 6. Table western Cape, and eastern Cape models in southeastern Massachusetts. Plymouth-Carver, [Pond locations are shown in figures 2 and 3. Number of ponds simulated the models: Plymouth-Carver 22 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass. conditions Pond with the Frost Fish Creek Frost Fish Creek with return flow in water level be - ment and pumping tween predevelop - maximum increase School House Pond Unnamed pond near Griffiths Pond School House Pond School House Pond School House Pond Unnamed pond near School House Pond School House Pond School House Pond School House Pond School House Pond School House Pond 0.3 0.4 0.4 0.3 0.3 0.3 0.3 0.4 0.4 0.4 0.4 0.3 0.3 in ft Maximum return flow conditions, increase in opment conditions for the tween prede - pumping with velopment and water level be - conditions and pumping maximum de - Pond with the level between crease in water predevelopment with return flow Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond in ft -3.4 -3.1 -3.0 -2.9 -2.9 -3.0 -3.3 -3.6 -3.7 -3.6 -3.5 -3.4 -3.4 conditions, and pumping Maximum de - level between crease in water predevelopment with return flow Pond with conditions the maximum level between predevelopment and pumping only decrease in water Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond Grassy Pond , 218; western Cape, 101; and eastern 72. ≥, greater than or equal to; ft, foot] in ft -4.7 -4.2 -4.1 -3.9 -3.8 -4.0 -4.4 -4.8 -5.0 -4.9 -4.8 -4.7 -4.7 tions, Eastern Cape model Maximum only condi - water level decrease in development and pumping between pre - 76 75 72 71 74 75 75 78 82 82 81 78 75 ≥ 0.1 ft and pumping ponds where Percentage of the difference level between conditions was (increase or de - predevelopment with return flow crease) in water 86 86 86 85 86 83 85 85 86 86 88 86 85 between ment and conditions was ≥ 0.1 ft predevelop - ponds where pumping only in water level Percentage of the difference - 55 54 52 51 53 54 54 56 59 59 58 56 54 ≥ 0.1 ft and pumping conditions was predevelopment with return flow where the differ decrease) in wa - Number of ponds ence (increase or between level ter - 62 62 62 61 62 60 61 61 62 62 63 62 61 ment and the differ Number of conditions was ≥ 0.1 ft predevelop - ponds where pumping only ence in water level between Summary of changes in pond levels under pumping only and with wastewater return flow conditions compared predevel
period Simulation January February March April May June July August September October November December Steady state Table 6. Table western Cape, and eastern Cape models in southeastern Massachusetts.—Continued Plymouth-Carver, [Pond locations are shown in figures 2 and 3. Number of ponds simulated the models: Plymouth-Carver Simulated Responses of Streamflows and Pond Levels to Pumping and Wastewater Return Flows 23 9 7 8 7 7 7 6 7 5 7 4 7 Eastern Cape 3 7 2 7 1 7 0 7 9 6 8 6 7 6 6 6 5 6 4 6 3 6 2 6 1 6 0 6 9 5 8 5 Western Cape 7 5 6 5 5 5 4 5 EXPLANATION 3 5 2 5 1 5 0 5 9 4 8 4 7 4 Predevelopment Pumping only Pumping with wastewater return flow 6 4 August streamflow in cubic feet per second for each condition 5 4 4 4 3 4 2 4 1 4 0 Subbasin 4 9 3 8 3 7 3 6 3 5 3 4 3 3 3 2 3 1 3 0 3 9 2 8 2 7 2 6 2 5 2 4 2 3 2 2 2 1 Plymouth-Carver 2 0 2 9 1 8 1 7 1 6 1 5 1 4 1 3 1 2 1 1 1 0 1 9 8 7 6 5 4 August streamflows under predevelopment, pumping only, and pumping with wastewater return flow conditions at subbasin outlets in the Plymouth-Carver, and pumping with wastewater return flow conditions at subbasin outlets in the Plymouth-Carver, August streamflows under predevelopment, pumping only, 3
2
0
70 6 0 5 0 4 0 3 0 2 0 1 0 August streamflow, in cubic feet per second second per feet cubic in streamflow, August Figure 11. western Cape, and eastern Cape model areas in southeastern Massachusetts. Subbasin prefix SB– omitted from subbasin identificat ion numbers for clarity. 24 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass. Eastern Cape Western Cape EXPLANATION , and pumping with wastewater return flow conditions at subbasin Predevelopment Pumping only Pumping with wastewater return flow August streamflow in cubic feet per second square mile for each condition Subbasin Plymouth-Carver August streamflows normalized by subbasin area under predevelopment, pumping only
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79
5 4 3 2 1 0 August streamflow, in cubic feet per second per square mile mile square per second per feet cubic in streamflow, August Figure 12. western Cape, and eastern Cape model areas in southeastern Massachusetts. Subbasin prefix SB– omitted from subbasin identification outlets in the Plymouth-Carver, numbers for clarity. Simulated Responses of Streamflows and Pond Levels to Pumping and Wastewater Return Flows 25
Pumping Only Conditions flows exceeded reductions in streamflow from pumping (if present) for a net increase in streamflow compared with Percentage alterations to average January, April, August, predevelopment conditions. Decreased streamflows indicate and October streamflows under pumping only conditions that enhanced recharge from wastewater return flows did not are shown by subbasin in figure 13. These results show that exceed reductions in streamflow from pumping, resulting in the percentage streamflow decreases in response to pumping a net decrease in streamflow compared with predevelopment generally were largest during the low-streamflow months conditions. The largest simulated depletions by model area of August and October. Simulated percentage alterations for August were 100 percent (went dry) for subbasin SB–27 of average August streamflows are shown in map view for (Indian Brook, Plymouth-Carver model), 18.5 percent for the subbasins in the model areas in figure 14. The greatest subbasin SB–70 (Shawme Lake, western Cape model), and simulated depletions by model area for August were 59.7 percent for subbasin SB–77 (Red River, eastern Cape 100 percent (the simulated streamflow under pumping only model). The largest surcharged streamflows by model area conditions was zero at the outlet point of the subbasin, thus for August were 43.7 percent for subbasin SB–26 (unnamed giving the appearance of a large streamflow depletion for the tributary to Salt Pond, Plymouth-Carver model), 22.1 percent subbasin, when only the last 400 ft at the downstream end of for subbasin SB–65 (unnamed tributary to Centerville River, the simulated stream went dry) for subbasin SB–27 (Indian western Cape model), and 2.3 percent for subbasin SB–74 Brook, Plymouth-Carver model), 37.7 percent for subbasin (unnamed tributary to Herring River, eastern Cape model). SB–66 (Hawes Run, western Cape model), and 66.9 percent Median August streamflow alterations for pumping with for subbasin SB–77 (Red River, eastern Cape model). The wastewater return flow conditions for the subbasins were median average August streamflow alteration at subbasin –2.9 percent for the Plymouth-Carver, –1.4 percent for the outlets under pumping only conditions by model area was western Cape, and –2.6 percent for the eastern Cape model –6.6 percent for the Plymouth-Carver, –9.1 percent for the areas. Alterations of average August streamflows at most western Cape, and –8.8 percent for the eastern Cape model subbasin outlets were near median values (for example, 58 of areas. Overall, percentage streamflow depletions for pumping 78 were within 10 percent of predevelopment streamflows). Of only conditions were larger under average August conditions the subbasins with simulated surcharged streamflows (fig. 15), than under long-term average conditions. 19 subbasins were surcharged up to 10 percent, and 5 were The results for subbasins SB–23, SB–27, and SB–78 surcharged between 10 and 44 percent. demonstrate the nuances of using groundwater model output All the subbasins that showed surcharges for pumping to examine streamflow changes at various scales. Similar with wastewater return flow conditions showed varying to subbasin SB–23 (Herring River) for long-term average degrees of depletion for pumping only conditions. One conditions, subbasin SB–27 (Indian Brook) was a losing example from the Plymouth-Carver model area was subbasin stream under pumping only conditions near the coast. If SB–24 (unnamed tributary to Cape Cod Canal in Bourne), streamflow in the fourth upstream cell from the downstream with a comparatively low predevelopment August streamflow end of Indian Brook were used rather than streamflow in the (0.98 ft3/s), which showed an 18.2 percent depletion for last cell, the depletion for average August conditions would pumping only conditions and a 2.8 percent surcharge for be 69.7 percent rather than 100 percent. In both subbasins, pumping with wastewater return flow conditions (fig. 15). there was streamflow under pumping only conditions in the Streamflow in subbasin SB–24 was affected by additional stream cells immediately upstream of the cells chosen to be recharge to the aquifer from septic-system return flow in an the outlet points, but zero streamflow at the outlet points. area of water lines without sewering and two production wells Similarly, in the last cell in subbasin SB–78, there was no (fig. 2), only one of which was active during 2005. In this simulated streamflow for most months (results show the subbasin, the amount of increased aquifer recharge was large cell had streamflow in February, March, and April) under enough to effect a small surcharge in streamflow compared predevelopment conditions, but the cell had no streamflow for with the rate of water pumped from the well. all months under pumping only and pumping with wastewater Results for subbasins similar to those shown in return flow conditions. Because of this, figure 13 indicates a figures 13 and 14 for pumping only conditions were compiled 100-percent depletion for April and none for the other months. for pumping with wastewater return flow conditions (figs. 16 and 17). Figure 16 shows simulated alterations in Pumping With Wastewater Return Flow Conditions average January, April, August, and October streamflows Monthly simulations under pumping with wastewater under pumping with wastewater return flow conditions in return flow conditions showed subbasins with both decreased comparison with predevelopment conditions at the outlets and increased streamflows compared with predevelopment of the subbasins. Overall, as with pumping only conditions, conditions. A comparison of alterations due to pumping only results in figure 16 show that percentage streamflow depletions and pumping with wastewater return flow conditions sorted were largest during the low-streamflow months of August and by values for alteration from pumping with wastewater October. Streamflow surcharges were more variable by month return flows is shown in figure 15. Increased streamflows but also were largest during the low-streamflow months in indicate that enhanced recharge from wastewater return most subbasins. Figure 17 shows results for average August 26 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass. 9 7 8 7 7 7 6 7 5 7 4 7 Eastern Cape 3 7 2 7 1 7 0 7 9 6 8 6 7 6 6 6 5 6 4 6 3 6 2 6 1 6 0 6 9 5 8 Western Cape 5 7 5 6 5 5 5 4 5 3 5 2 5 1 5 0 EXPLANATION 5 9 4 8 4 7 4 6 4 5 4 4 4 3 4 2 4 1 4 r i l gust tober nuary 0 a 4 A p A u O c J 9 3 Alteration of streamflow from predevelopment conditions, in percent. Values based on the difference in flows cubic feet per second square mile between predevelopment and pumping only conditions at the outlet of each subbasin 8 3 7 3 6 3 Subbasin 5 3 4 3 3 3 2 3 1 3 0 3 9 2 8 2 7 2 6 2 5 2 4 2 3 2 2 2 Plymouth-Carver 1 2 0 2 9 1 8 1 7 1 6 1 5 1 4 1 3 1 2 1 1 1 0 1 9 8 7 6 Depleted 5 imulated percentage alteration of average monthly (January, April, August, and October) streamflows for subbasins in the Plymouth-Carver, western Cape, April, August, and October) streamflows for subbasins in the Plymouth-Carver, imulated percentage alteration of average monthly (January, S 4 3
2 Pumping only 0
1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0
------Alteration of streamflow from predevelopment conditions, in percent in conditions, predevelopment from streamflow of Alteration 1 0 - Figure 13. and eastern Cape model areas in southeastern Massachusetts. Subbasin prefix SB– omitted from subbasin identification numbers f or clarity. Simulated Responses of Streamflows and Pond Levels to Pumping and Wastewater Return Flows 27 10 MILES 70° 10 KILOMETERS 77 5 76 74 5 79 78 75 73 0 0 67 Eastern Cape (Monomoy) model 66 0 10 20 3 40 - - - 65 - 0 to 9.9 to - -19.9 to -29.9 to -39.9 to -10 0 EXPLANATION 28 29 37 66 35 Pond Stream subbasin was based (“sb_id” in table and GIS shapefiles) Simulated zone on which the Alteration of average August streamflow for pumping only conditions, in percent, and subbasin identification number —Prefix SB– omitted for clarity Outlet point of subbasin 63 64 68 69 62 Western Cape (Sagamore) model Cape Western 61 60 58 59 70 57 56 71 55 24 72 25 54 52 70°33' 26 27 48 53 28 23 22 49 50 51 21 Plymouth-Carver model 30 18 17 20 31 29 16 19 15 14 42 45 43 33 41 6 32 13 11 44 40 39 12 9 2 10 37 46 38 7 8 3 36 34 5 35 4 imulated alteration of average August streamflow for subbasins in the Plymouth-Carver, western Cape, and eastern Cape model areas in imulated alteration of average August streamflow for subbasins in the Plymouth-Carver, 47 S
Base from U.S. Geological Survey and Massachusetts Office of Geographic Information data, 2001 Massachusetts State Plane Coordinate System, mainland zone 19, North American Datum 1983, 1:25,000 42° 41°45' Figure 14. southeastern Massachusetts for pumping only conditions compared with predevelopment at the outlet of each subbas in. Subbasin areas that are part of a larger subbasin shown as stacked sequence with the furthest upstream at top t he sequence. 28 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass. 6 2 5 6 4 5 9 1 0 1 8 3 6 4 1 5 9 0 5 1 6 2 7 4 2 6 5 4 7 9 7 4 3 1 3 7 5 5 5 Surcharged 0 4 8 2 2 4 8 5 8 7 3 2 9 4 7 4 3 3 1 1 5 2 3 5 2 5 8 EXPLANATION 1 4 5 1 5 4 3 7 5 0 6 7 0 3 4 Subbasin 1 2 Pumping only Pumping with wastewater return flow (results are shown sorted by these values from most depleted to surcharged) 1 2 Alteration of August streamflow from predevelopment conditions, in percent. Values based on the difference in flows cubic feet per second square mile from predevelopment conditions at the outlet each subbasin for condition 6 4 6 7 1 2 2 3 4 5 7 6 7 3 3 6 9 5 2 3 8 6 4 4 9 2 8 1 2 9 6 4 6 9 3 1 2 7 6 3 Depleted 1 6 6 8 4 1 7 6 1 0 7 7 3 6 3 0 2 imulated alterations of August streamflows for pumping only and wastewater return flow conditions compared with pr edevelopment 7 7 S 5 3
7 2 Alteration of average August flow 0
1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 5 0 4 0 3 0 2 0 1 0
------1 0 Alteration of streamflow from predevelopment conditions, in percent in conditions, predevelopment from streamflow of Alteration - Figure 15. western Cape, and eastern Cape model areas in southeastern Massachusetts. Subbasin prefix SB– omitted from subbasin conditions in the Plymouth-Carver, Subbasins SB–23 and SB–78 are discussed in this report. identification numbers for clarity. Simulated Responses of Streamflows and Pond Levels to Pumping and Wastewater Return Flows 29 79 75 76 77 78 74 Eastern Cape 73 72 66 67 68 69 70 71 65 64 63 62 61 Western Cape 58 59 60 55 56 57 54 EXPLANATION 52 53 51 50 47 48 49 46 45 41 42 43 44 January April August October 40 Alteration of streamflow from predevelopment conditions, in percent. Values based on the difference in flows cubic feet per second square mile between predevelopment and pumping with wastewater return flow conditions at the outlet of each subbasin 39 38 37 36 Subbasin 35 34 32 33 31 29 30 28 27 26 25 24 23 22 Plymouth-Carver 20 21 19 14 15 16 17 18 13 11 12 10 9 Surcharged Depleted imulated alterations in average January, April, August, and October streamflows for pumping with wastewater return flow conditions compared S imulated alterations in average January,
2 3 4 5 6 7 8 Pumping with wastewater return flows 0
50 40 30 20 10
-10 -20 -30 -40 -50 -60 -70 -80 -90 Alteration of streamflow from predevelopment conditions, in percent in conditions, predevelopment from streamflow of Alteration -100 Figure 16. predevelopment conditions at the outlets of subbasins in the Plymouth-Carver, western Cape, and eastern Cape model areas in southeastern Massachusetts. Subbasin predevelopment conditions at the outlets of subbasins in Plymouth-Carver, prefix SB– omitted from subbasin identification numbers for clarity. 30 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass. 10 MILES 70° 77 5 76 74 79 78 75 73 0 0 5 10 KILOMETERS 67 Eastern Cape (Monomoy) model 66 65 > 40 > 30to 40 > 2030 to > 1020 to to -9.9 10 -10-19.9 to -20-29.9 to -30-39.9 to -100-40 to EXPLANATION Simulated pond Simulated stream Outlet point of subbasin and subbasin identifier —Prefix SB– omitted for clarity Alteration of average August streamflow for pumping with wastewater return flow conditions, in percent 76 63 64 68 69 62 61 Western Cape (Sagamore) model Cape Western 60 58 59 70 57 56 71 55 24 72 25 54 52 70°33' 26 27 48 53 28 23 22 49 50 51 21 Plymouth-Carver model 30 18 17 20 31 29 16 19 15 14 42 45 43 33 41 6 32 13 11 44 40 39 12 9 2 10 37 46 38 7 8 3 36 34 5 35 4 imulated alterations of average August streamflow for subbasins in the Plymouth-Carver, western Cape, and eastern Cape model areas S imulated alterations of average August streamflow for subbasins in the Plymouth-Carver, 47
Base from U.S. Geological Survey and Massachusetts Office of Geographic Information data, 2001 Massachusetts State Plane Coordinate System, mainland zone 19, North American Datum 1983, 1:25,000 42° 41°45' Figure 17. in southeastern Massachusetts for pumping with wastewater return flow conditions compared predevelopment at t he outlet of each subbasin. Subbasin areas that are part of a larger subbasin shown as stacked sequence with the furthest upstr eam at top of the sequence. Simulated Responses of Streamflows and Pond Levels to Pumping and Wastewater Return Flows 31 streamflows in map view. The gray-shaded areas show that were considered to be negligible. Consequently, the results simulated alterations of average August streamflow under described in this section reflect changes in pond levels of pumping with wastewater return flow conditions were between 0.1 ft or greater. Simulated alterations are summarized in this –10 percent (depleted) and +10 percent (surcharged) for most section, but more detailed results for all simulated conditions of the subbasins in the study area. are available in the pond water level shapefiles in the ArcMap project in appendix 2. Alteration of Streamflows at Stream Model Cells Long-Term Average Conditions
The groundwater flow models provide streamflow and The percentages of the total number of ponds where the changes in streamflow for each 400-by 400-ft stream cell difference in long-term average water levels was equal to in the study area. Consequently, groundwater flow models or greater than 0.1 ft (table 6) between predevelopment and simulate streamflow alteration within subbasins as well as at pumping only conditions were 35 percent for the Plymouth- subbasin outlets, in contrast to the topographically derived Carver model, 85 percent for the western Cape model, and subbasins in the rest of the Commonwealth where alteration 85 percent for the eastern Cape model. For pumping with results are available only at subbasin outlets. Simulated wastewater return flow conditions, the percentages were streamflow alteration for pumping with wastewater return 28 percent for the Plymouth-Carver model, 67 percent for flow conditions by stream cell for August for the Plymouth- the western Cape model, and 75 percent for the eastern Carver, western Cape, and eastern Cape model areas is shown Cape model. Overall, a smaller percentage of ponds in the in figures 18, 19, and 20, respectively. Changes in streamflow Plymouth-Carver region were influenced by pumping only or are shown as absolute differences and as percentages from pumping with wastewater return flow conditions compared predevelopment streamflows. An example of differences with ponds on Cape Cod. As expected, fewer ponds had a between results at stream cells and outlet points is provided decrease in water levels when wastewater return flows were by a comparison of streamflows at the outlet point of subbasin included in comparison with the pumping only conditions SB–2 with streamflows just downstream of Kings Pond in (table 6). the unnamed tributary to South Meadow Brook (fig. 18). The largest decrease due to pumping was 4.8 ft at Great The simulated decrease in streamflow under pumping with South Pond in Plymouth (fig. 2; table 6). The largest decrease wastewater return flow conditions at the outlet point of due to pumping with wastewater return flows was 4.6 ft, also subbasin SB–2 was about 0.6 ft3/s from a predevelopment at Great South Pond. The largest increase due to pumping with streamflow of about 6.5 ft3/s (about 9 percent). However, wastewater return flows was almost 0.5 ft at an unnamed pond within this subbasin, there was a group of stream cells near Town Forest in Pembroke. Results for the western Cape downstream of Kings Pond that showed a similar decrease model area show that the largest decrease due to pumping was in streamflow of about 0.7 ft3/s, but the predevelopment 3.8 ft at Mary Dunn Pond in Barnstable. The largest decrease streamflow was lower, about 0.8 ft3/s, resulting in a larger due to pumping with wastewater return flows was 3.2 ft at percentage decrease of greater than 50 percent. Consequently, Long Pond in Falmouth. The largest increase due to pumping although the streamflow alteration at the subbasin scale was with wastewater return flows was 0.9 ft at Wequaquet Lake less than 10 percent, this particular subbasin contained a in Barnstable (fig. 3). Results for the eastern Cape model area group of stream cells further upstream that showed alterations show that the largest decrease due to pumping was 4.7 ft at to streamflow greater than 50 percent. The benefit of using Grassy Pond in Dennis. The largest decrease due to pumping results from groundwater models for this analysis is that, with wastewater return flows was 3.4 ft, also at Grassy Pond. although simulated streamflow alterations were summarized The largest increase due to pumping with wastewater return by subbasin to be consistent with previous studies, alterations flows was 0.3 ft at School House Pond. at the scale of individual stream cells are also available so that spatial patterns of streamflow alteration within a particular subbasin can be evaluated (appendix 2). Average Monthly Conditions A greater percentage of ponds were affected by pumping Alteration of Pond Levels only and pumping with wastewater return flow conditions on Cape Cod than in the Plymouth Carver region. An average Similar to streamflows, pond levels can either increase of 37 and 28 percent of simulated ponds were influenced or decrease in response to pumping and wastewater return by pumping only and pumping with wastewater return flow flows. The hydrologic position of wells and enhanced return conditions, respectively, in the Plymouth Carver region, flows in relation to ponds, the pumping and wastewater return compared with about 83 and 69 percent in the western Cape, flow rates, and the number of wells are factors that influence and 86 and 76 percent in the eastern Cape model areas which ponds are affected by pumping and wastewater return (table 6). The group of ponds that had the greatest changes flows. Increases or decreases in pond levels of less than 0.1 ft in monthly water levels was fairly consistent throughout
32 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass.
Brook Brook
10 MILES
Indian Indian Indian
River River River
Herring Herring Herring
≥ 10 5.0 to 9.9 1.0 to 4.9 0.1 to 0.9 0.09 to -0.09 (no change) -0.1 to -0.9 -1 to -4.9 -5 to -9.9 -10 to -14.9 -15 to -19.9 -20 to -29.9 -30 to -49.9 ≤ -50
Great Herring Herring Pond Pond
Beaver Dam Brook Brook Dam Dam Beaver Beaver EXPLANATION 10 KILOMETERS Plymouth-Carver model
Simulated pond Cape Cod Canal Cod Cape 5 Halfway Pond Pond Halfway
Streamflow alteration, in percent, for pumping with wastewater return flow conditions —Negative indicates a decrease in flow from predevelopment conditions
River River
Agawam Agawam
70°37'30" Negro Pond 5 , as percentage change. B
Island Creek Island Creek
Town Brook Island Creek Pond Island Creek Pond South Triangle Triangle Pond Pond
Maple Springs Brook Springs Maple Great South South Pond Pond Brook Springs Maple East Head Pond Union Pond Pond Kings Pond Pond Mill Pond Billington Sea Billington Sea
Powderhorn Pond Pond
0 0
River River
ankinco ankinco ankinco ankinco W W Triangle Pond Pond
Soules Pond Pond
South River River South South
Jones River Goose Pond Pond
SB − 2 Indian Brook Brook Indian Indian 70°47'30" subbasin
Outlet point of
eweantic River eweantic eweantic River eweantic
W Silver Lake W Unnamed pond near Town Forest
Crossman Pond Pond
Brook Brook Brook Brook
South Meadow Brook Brook Meadow South
South Meadow Meadow Meadow South South Unnamed tributary to to tributary Unnamed B. Percent , in absolute values (cubic feet per second) and
A
Brook Brook
Indian Indian Indian
Pond
River River River
Bartlett Bartlett Herring Herring Herring 2 -8 ≥ ≤
1 to 1.9 0.1 to 0.9 0.09 to -0.09 (no change) -0.1 to -0.9 -1 to -1.9 -2 to -3.9 -4 to -5.9 -6 to -7.9
Great Herring Herring Pond Pond
Beaver Dam Brook Brook Dam Dam Beaver Beaver EXPLANATION
Simulated pond Plymouth-Carver model Cape Cod Canal Cod Cape Halfway Pond Pond Halfway
Streamflow alteration, in cubic feet per second, for pumping with wastewater return flow conditions — Negative indicates a decrease in flow from predevelopment conditions River River
Agawam Agawam
70°37'30" Negro Pond
Island Creek Island Creek
Town Brook Island Creek Pond Island Creek Pond South Triangle Triangle Pond Pond
Maple Springs Brook Springs Maple Great South South Pond Pond Brook Springs Maple East Head Pond Union Pond Pond Kings Pond Pond Mill Pond Billington Sea Billington Sea
Powderhorn Pond Pond
River River
ankinco ankinco ankinco ankinco W W Triangle Pond Pond
Soules Pond Pond
South River River South South
Jones River Goose Pond Pond
Indian Brook Indian SB − 2 Brook Indian 70°47'30" subbasin
Outlet point of
eweantic River eweantic eweantic River eweantic
W W imulated effects of pumping with wastewater return flow on average August streamflow in stream cells the Plymouth-Carver m odel area southeastern Silver Lake S Unnamed pond near Town Forest Crossman Pond Pond
South Meadow Brook Brook Meadow South South Meadow Brook Brook Meadow South Brook Brook Brook Brook
unnamed tributary to to tributary unnamed South Meadow Meadow Meadow South South Unnamed tributary to to tributary Unnamed A. Cubic feet per second Base from U.S. Geological Survey and Massachusetts Office of Geographic Information data, 2001 Massachusetts State Plane Coordinate System, mainland zone 19, North American Datum 1983, 1:25,000 42° 41°45' Figure 18. Massachusetts compared with streamflows under predevelopment conditions Simulated Responses of Streamflows and Pond Levels to Pumping and Wastewater Return Flows 33
A. Cubic feet per second 70°33' 70°16'30"
Western Cape (Sagamore) model
41°43'30" Lovells Pond
Mashpee-Wakeby Shallow Pond Pond Wequaquet Lake Long Pond Mary Marston Mills Dunn River Ashumet Pond Little River Pond Mashpee River Long 41°38' CoonamessettPond Pond Simmons Pond Coonamessett EXPLANATION River Streamflow alteration, in cubic feet Long per second, for pumping with wastewater return Pond flow conditions—Negative indicates a decrease Quashnet River Quashnet River in flow from predevelopment conditions ≥ 2 -0.1 to -0.9 Grews 1 to 1.9 -1 to -1.9 Pond 0.1 to 0.9 -2 to -3.9 0.09 to -0.09 (no change) -4 to -5.9 -6 to -7.9 ≤ -8 Simulated pond
B. Percent
Western Cape (Sagamore) model
41°43'30" Lovells Pond
Mashpee-Wakeby Shallow Pond Pond Wequaquet Lake Long Pond Mary Marston Mills Dunn River Ashumet Pond Little River Pond Mashpee River
41°38' Coonamessett Pond Simmons Pond Coonamessett EXPLANATION River Streamflow alteration, in percent, for Long pumping with wastewater return flow conditions— Pond Negative indicates a decrease in flow from Quashnet River predevelopment conditions ≥ 10 -0.1 to -0.9 Grews 5.0 to 9.9 -1 to -4.9 Pond 1.0 to 4.9 -5 to -9.9 0.1 to 0.9 -10 to -14.9 0.09 to -0.09 (no change) -15 to -19.9 -20 to -29.9 0 5 10 MILES -30 to -49.9 ≤ -50 0 5 10 KILOMETERS Base from U.S. Geological Survey and Massachusetts Office of Geographic Information data, 2001 Massachusetts State Plane Coordinate System, mainland zone 19, North American Datum 1983, 1:25,000
Figure 19. Simulated effects of pumping with wastewater return flow on average August streamflow in stream cells in the western Cape model area in southeastern Massachusetts compared with streamflows under predevelopment conditions A, in absolute values (cubic feet per second) and B, as percentage change. 34 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass.
A. Cubic feet per second 70°11' 70° 41°49' EXPLANATION Eastern Cape (Monomoy) model Streamflow alteration, in cubic feet per second, for pumping with wastewater return flow conditions— Negative indicates a decrease in flow from predevelopment conditions Simmons Pond ≥ 2 Run Pond School House 1 to 1.9 Pond Bakers 0.1 to 0.9 Pond 0.09 to -0.09 (no change) Grassy -0.1 to -0.9 41°43'30" Pond -1 to -1.9 -2 to -3.9 -4 to -5.9 White -6 to -7.9 Pond ≤ -8
Simulated pond
B. Percent 41°49' EXPLANATION Streamflow alteration, in percent, Eastern Cape (Monomoy) model for pumping with wastewater return flow conditions—Negative indicates a decrease in flow from predevelopment conditions ≥ 10 Simmons Pond 5.0 to 9.9 Run Pond School House Pond 1.0 to 4.9 Bakers 0.1 to 0.9 Pond 0.09 to -0.09 (no change) Grassy -0.1 to -0.9 41°43'30" Pond -1 to -4.9 -5 to -9.9 -10 to -14.9 -15 to -19.9 White -20 to -29.9 Pond -30 to -49.9 ≤ -50
Simulated pond
Base from U.S. Geological Survey and Massachusetts Office of Geographic Information data, 2001, Massachusetts State Plane Coordinate System, mainland zone 19 North American Datum 1983, 1:25,000 0 5 10 MILES
0 5 10 KILOMETERS
Figure 20. Simulated effects of pumping with wastewater return flow on average August streamflows in stream cells in the eastern Cape model area in southeastern Massachusetts compared with streamflows under predevelopment conditions A, in absolute values (cubic feet per second) and B, as percentage change. Simulated Responses of Streamflows and Pond Levels to Pumping and Wastewater Return Flows 35 the year. These included Great South Pond, Negro Pond, Falmouth (fig. 22) had the largest simulated decreases in Powderhorn Pond, South Triangle Pond, and Triangle Pond monthly water levels due to pumping, and Long Pond had the in the Plymouth-Carver model area (fig. 21); Long Pond in largest decrease due to pumping with wastewater return flows. Falmouth, Grews Pond, Simmons Pond, Mary Dunn Pond, The largest increases due to pumping with wastewater return and Little Pond in the western Cape model area (fig. 22); and flows were at Shallow Pond (0.9 ft) and Wequaquet Lake Grassy Pond, Bakers Pond, Simmons Pond, Run Pond, and (0.8 ft). In the eastern Cape model area, Grassy Pond (fig. 23) White Pond in the eastern Cape model area (fig. 23). Changes had the largest simulated decrease in monthly water level due in average August pond water levels for pumping only and for to both pumping only and pumping with wastewater return pumping with wastewater return flow conditions compared flows (5.0 and 3.7 ft, respectively). The largest increase due to predevelopment conditions are shown in figures 21 to pumping with wastewater return flow was at School House through 23. Pond (0.4 ft). Hydrographs of simulated average monthly pond levels for all ponds are included in appendix 2. The hydrographs shown in figure 24 are two examples of the effects of Landscape Characteristics in Contributing simulated average monthly pond-level changes from the Areas Plymouth-Carver model area, showing differing effects of pumping and wastewater return flows. The hydrograph Once contributing areas (subbasins and hydrologic units) of Goose Pond (figs. 21 and 24) shows that pond level were delineated, the following landscape characteristics increased under pumping with wastewater return flow described in Weiskel and others (2010) and Armstrong and conditions in comparison with predevelopment conditions others (2011) for the rest of Massachusetts were determined and decreased under pumping only conditions in comparison for contributing areas in southeastern Massachusetts: with predevelopment conditions, whereas the hydrograph • channel slope; of Triangle Pond (figs. 21 and 24) shows that pond levels decreased in comparison with predevelopment conditions • total undammed stream length; for both pumping only and pumping with wastewater return • percent wetland in a 787.4-ft (240-meter [m]) buffer flow conditions. 393.7 ft (120 m) from the stream centerline; In general, monthly pond water level alterations were fairly consistent throughout the year. However, a few ponds • percent agriculture in a 787.4-ft (240 m) buffer 393.7 ft in the Plymouth-Carver model area showed slightly more (120 m) from the stream centerline; variability by month; these included Mill Pond, Soules Pond, Crossman Pond, and Silver Lake. Mill Pond and Soules Pond • percent forest; are small ponds that were simulated in the same model cells • percent open water; as streams and, therefore, changes in streamflow may have influenced the pond levels in these areas. Crossman Pond is • percent impervious cover; an isolated pond located between a stream and a production well, and the pond level could be influenced by the combined • percent sand and gravel; and effect of those nearby features. Silver Lake is a large reservoir, • the average August withdrawal ratio (ratio of with- and resulting water levels are related to the simulated monthly drawals to unaltered streamflows). rates of withdrawal from the lake (Silver Lake is discussed in greater detail in the “Limitations” section of this report). These landscape characteristics were determined for As with long-term average results, Great South Pond all 78 subbasins (table 3). Percent impervious cover was (fig. 21) had the largest monthly change among ponds in the also determined at the hydrologic-unit (or local) scale Plymouth-Carver model, with consistent decreases in each (table 4; fig. 5). The characteristics were determined under month of about 4.8 and 4.6 ft for pumping only conditions predevelopment conditions for all 78 subbasins (table 3), and for pumping with wastewater return flow conditions, including the 61 headwater subbasins (figs. 4 and 6) and the respectively. However, Great South Pond is a special case 17 nested subbasins that contain one or more overlapping due to the relatively consistent withdrawal directly from upstream subbasins (figs. 4 and 7). Landscape characteristics the pond. Ponds in the Plymouth-Carver model with the were determined for each of the 17 nested subbasins in the next greatest change are shown in table 6. These include total drainage area to the respective stream outlet point. Triangle Pond, with a consistent monthly decrease of about The percent impervious cover was the only landscape 4 ft under pumping only conditions, and Negro Pond, with a characteristic that also was calculated by hydrologic unit consistent monthly decrease of about 3.5 ft under pumping (table 4). This was done for consistency with the study for the with wastewater return flow conditions. In general, the largest rest of Massachusetts in Weiskel and others (2010). increase in pond level (0.4 ft) in response to pumping with In each groundwater model, the physical properties wastewater return flows was at Goose Pond (fig. 21). In the of streams were simplified and mapped to the regional western Cape model, Mary Dunn Pond and Long Pond in model grids, as represented in the STR package input file of
36 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass.
Brook Brook
10 MILES
Indian Indian Indian
River River River
Herring Herring Herring Great Herring Herring Pond Pond
-4
Simulated stream cell 0.5 to 1.0 0.1 to 0.49 0.09 to -0.09 (no change) -0.1 to -0.49 -0.5 to -0.9 -1.0 to -1.49 -1.5 to -1.9 -2.0 to -2.49 -2.5 to -2.9 -3.0 to -3.49 -3.5 to -3.9 ≤
Beaver Dam Brook Dam Beaver EXPLANATION Brook Dam Beaver
10 KILOMETERS Cape Cod Canal Cod Cape 5 Halfway Pond Pond Halfway
Pond water level change for average August conditions, in feet —Negative values indicate a decrease in water level in comparison to predevelopment conditions
River River
Agawam Agawam
70°37'30" Negro Pond 5
Island Creek Island Creek
Town Brook Island Creek Pond Island Creek Pond South Triangle Triangle Pond Pond
Maple Springs Brook Springs Maple Great South South Pond Pond Brook Springs Maple East Head Pond Union Pond Pond Kings Pond Pond Mill Pond Billington Sea Billington Sea
Powderhorn Pond Pond
0 0
River River
ankinco ankinco ankinco ankinco W W Triangle Pond Pond
Soules Pond Pond
South River River South South
Jones River Goose Pond Pond
Indian Brook Brook Indian Indian 70°47'30" , pumping with wastewater return flow conditions for the Plymouth-
B eweantic River eweantic eweantic River eweantic
W Silver Lake W Unnamed pond near Town Forest
Crossman Pond Pond
Brook Brook Brook Brook
South Meadow Brook Brook Meadow South South Meadow Meadow Meadow South South Unnamed tributary to to tributary Unnamed B . Pumping with wastewater return flows , pumping only and
A
Brook Brook
Indian Indian Indian
River River River
Herring Herring Herring
Great Herring Herring Pond Pond
Beaver Dam Brook Brook Dam Dam Beaver Beaver
Plymouth-Carver model Canal Cod Cape
Halfway Pond Pond Halfway
River River
Agawam Agawam
70°37'30" Negro Pond
Island Creek Island Creek
Town Brook Island Creek Pond Island Creek Pond South Triangle Triangle Pond Pond
Maple Springs Brook Springs Maple Great South South Pond Pond Brook Springs Maple East Head Pond Union Pond Pond Kings Pond Pond Mill Pond Billington Sea Billington Sea
Powderhorn Pond Pond
River River
ankinco ankinco ankinco ankinco W W Triangle Pond Pond
Soules Pond Pond
South River River South South
Jones River Goose Pond Pond
Indian Brook Brook Indian Indian
70°47'30"
eweantic River eweantic eweantic River eweantic
W W imulated changes to average August pond water levels due Silver Lake S Unnamed pond near Town Forest Crossman Pond Pond
South Meadow Brook Brook Meadow South Brook Brook Brook Brook
South Meadow Brook Brook Meadow South
unnamed tributary to to tributary unnamed South Meadow Meadow Meadow South South Unnamed tributary to to tributary Unnamed A . Pumping only Base from U.S. Geological Survey and Massachusetts Office of Geographic Information data, 2001 Massachusetts State Plane Coordinate System, mainland zone 19, North American Datum 1983, 1:25,000 42° 41°45' Figure 21. Carver model area in southeastern Massachusetts. Simulated Responses of Streamflows and Pond Levels to Pumping and Wastewater Return Flows 37
A. Pumping only 70°33' 70°16'30"
Western Cape (Sagamore) model
41°43'30" Lovells Pond
Mashpee-Wakeby Shallow Pond Little Pond Pond Wequaquet Lake Long Pond Mary Marston Mills Dunn River Ashumet Pond Little River Pond Mashpee River Long 41°38' CoonamessettPond Pond Simmons Pond Coonamessett River Long Pond Quashnet River Quashnet River
Grews Pond
B. Pumping with wastewater return flows
Western Cape (Sagamore) model
41°43'30" Lovells Pond
Mashpee-Wakeby Shallow Pond Little Pond Pond Wequaquet Lake Long Pond Mary Marston Mills Dunn River Ashumet Pond Little River Pond Mashpee River Long 41°38' CoonamessettPond Pond Simmons Pond Coonamessett River EXPLANATION Long Pond water level change for average August conditions, Pond in feet—Negative values indicate a decrease in water level in Quashnet River comparison to predevelopment conditions Quashnet River 0.5 to 1.0 -2.5 to -2.9 0.1 to 0.49 -3.0 to -3.49 Grews Pond 0.09 to -0.09 (no change) -3.5 to -3.9 -0.1 to -0.49 ≤ -4 -0.5 to -0.9 Simulated stream cell -1.0 to -1.49 0 5 10 MILES -1.5 to -1.9 -2.0 to -2.49 0 5 10 KILOMETERS Base from U.S. Geological Survey and Massachusetts Office of Geographic Information data, 2001 Massachusetts State Plane Coordinate System, mainland zone 19, North American Datum 1983, 1:25,000
Figure 22. Simulated changes to average August pond water levels due to A, pumping only and B, pumping with wastewater return flow conditions for the western Cape model area in southeastern Massachusetts. 38 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass.
A. Pumping only 70°11' 70° 41°49' Eastern Cape (Monomoy) model
Simmons Pond Run Pond School House Pond Bakers Pond Grassy 41°43'30" Pond
White Pond EXPLANATION Pond water level change for average August conditions, in feet—Negative values indicate a decrease in water level in comparison to predevelopment conditions 0.5 to 1.0 0.1 to 0.49 0.09 to -0.09 (no change) -0.1 to -0.49 B. Pumping with wastewater return flows -0.5 to -0.9 -1.0 to -1.49 41°49' -1.5 to -1.9 Eastern Cape (Monomoy) model -2.0 to -2.49 -2.5 to -2.9 -3.0 to -3.49 -3.5 to -3.9 ≤ -4 Simmons Pond Simulated stream cell Run Pond School House Pond Bakers Pond Grassy 41°43'30" Pond
White Pond
Base from U.S. Geological Survey and Massachusetts Office of Geographic Information data, 2001, Massachusetts State Plane Coordinate System, mainland zone 19 North American Datum 1983, 1:25,000 0 5 10 MILES
0 5 10 KILOMETERS
Figure 23. Simulated changes to average August pond water levels due to A, pumping only and B, pumping with wastewater return flow conditions for the eastern Cape model area in southeastern Massachusetts. Simulated Responses of Streamflows and Pond Levels to Pumping and Wastewater Return Flows 39
A. Goose Pond 110
109
108
107
106 Water level, in feet 105
104 J F M A M J J A S O N D Month B. Triangle Pond 109
108
107
106
105 Water level, in feet 104
103 J F M A M J J A S O N D Month
EXPLANATION Water level Predevelopment Pumping only Pumping with wastewater return flow
Figure 24. Hydrographs from the Plymouth-Carver model area of simulated average monthly pond levels for predevelopment, pumping only, and pumping with wastewater return flow conditions for A, Goose Pond and B, Triangle Pond in southeastern Massachusetts. 40 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass.
MODFLOW (Prudic, 1989). Consequently, the calculated locations of dams (Massachusetts Office of Geographic results for the two landscape characteristics that involved Information, 2012) were available, those characteristics were length (channel slope and total undammed stream length) also determined by using these datasets for this analysis. The were based on a value of 400 ft, the length of simulated stream criteria for land cover determination used in the 2006 dataset in each model cell. Because of the gridded nature of the differed from those of the 1992 dataset, which accounted for groundwater models, slope could not be calculated in the same a portion of the difference in the results presented in table 3 manner as in Armstrong and others (2011). Elevations used to between the respective years. calculate channel slope were based on those specified in the Simulated average August streamflows were used to STR package input file. This characteristic in Armstrong and calculate the average August withdrawal ratio for subbasins others (2011) was known as local channel slope and was based in the three model areas in southeastern Massachusetts. on a 984.3-ft (300-m)-diameter circle about a sampling point. Armstrong and others (2011) determined that the withdrawal In this study, channel slope was calculated by determining the ratio (ratio of withdrawals to unaltered streamflows) of difference in elevation of the streambed between the upstream median August streamflow was an important characteristic and downstream ends of each hydrologic unit, then dividing in predicting fluvial fish abundance. However, in this by the length between these points (length was determined analysis, the withdrawal ratio of average, not median, August as the number of stream cells between each point, multiplied streamflow was calculated because the groundwater models by 400 ft). This result then was multiplied by 100 to yield simulate only average monthly streamflows. slope in percent. Even though slope (fig. 25A) was calculated Boxplots were developed to illustrate the similarity of over a greater distance compared with that in Armstrong and the landscape characteristics determined for the hydrologic others (2011), the resulting slope values overall were not as units and subbasins for southeastern Massachusetts in this steep as most of those of the Massachusetts water indicator study to the 1,379 Massachusetts water indicator subbasins subbasins of Weiskel and others (2010) and the local channel (Weiskel and others, 2010; Massachusetts Department of slope at 669 fish sampling sites of Armstrong and others Environmental Protection, 2014a) and the subbasins for (2011). This reflects the low topographic relief in southeastern 669 fish sampling sites (Armstrong and others, 2011) for the Massachusetts relative to the rest of the Commonwealth. rest of Massachusetts (fig. 25). Channel slope, percent wetland The total length of undammed main stem and tributary in a 787.4-ft (240-meter) buffer, withdrawal ratio for median streams was calculated between dams in both the upstream August streamflow, and percent impervious cover were used and downstream directions from the outlet point of each to predict fluvial fish abundance in Armstrong and others hydrologic unit. Some undammed lengths include streams (2011) and for determining the WMA biological category located in more than one hydrologic unit for hydrologic of a subbasin (Massachusetts Department of Environmental units located between other hydrologic units (for example Protection, 2014b). Boxplots were developed to compare hydrologic unit HU–36, which has the same undammed reach landscape characteristics of subbasins used in the three studies length as hydrologic units HU–34 and HU–35). The straight- (fig. 25). Additional boxplots compare the remaining five line distance through simulated ponds was also included in landscape characteristics that were computed for the 669 fish the total length if no simulated stream cells were located in sampling sites and those delineated in this analysis (fig. 26). the pond because it was assumed that aquatic organisms could Although most landscape characteristics were similar, move into and through a pond (for example, Bartlett Pond in channel slope, percent sand and gravel, undammed stream Beaver Dam Brook in subbasin SB–28 in the Plymouth-Carver length, and percent open water showed somewhat larger model area; figs. 2, 5, and 6). This characteristic did not rely differences among the studies than other characteristics on hydrologic unit or subbasin boundaries. (figs. 25 and 26). The boxplots of channel slope (fig. 25A) Geographic information system (GIS) processing was are separated into one graph for each report for comparison. used to determine the area of impervious cover, forest, open Median channel slopes for the Massachusetts water indicator water, and sand and gravel in each subbasin and was then and fish sampling site subbasins were similar at 0.4 and divided by the total area of the subbasin to obtain the percent 0.5 percent, respectively, and median slope was 0.2 percent for area of each landscape characteristic. The percent area of the southeastern Massachusetts hydrologic units. The August wetlands and agriculture in a 787.4–ft (240-m) buffer around withdrawal ratios (fig. 25C) are separated into two graphs to each stream (Armstrong and others, 2011) was determined by indicate that a difference exists in how the respective values using the same method. were calculated, but the graphs are juxtaposed so that the Unlike the other landscape characteristics, the percent resulting values from each report can be compared (median impervious cover also was calculated for each hydrologic values were 6.9, 4.3, and 8.3 percent for Massachusetts water unit by using the same method used for the subbasins. The indicator, fish sampling site, and southeastern Massachusetts same GIS datasets of land cover in 1992, impervious cover, subbasins, respectively). Percent wetland (fig. 25B) and and sand and gravel used to determine the characteristics percent impervious cover (fig. 25D) were calculated similarly in Armstrong and others (2011) were used in this study for for each report and are shown on the same graph for consistency between the studies. However, because more comparison. Median values for percent wetland were 24.4, recent versions of land cover for 2006 (Fry, 2011) and 14.3, and 12.2 for Massachusetts water indicator, fish sampling Simulated Responses of Streamflows and Pond Levels to Pumping and Wastewater Return Flows 41
A. Channel slope B. Percent wetland in a 787.4 ft (240 m) buffer Fish Fish sampling SE Mass. sampling MWI site hydrologic MWI site SE Mass. subbasins subbasins units subbasins subbasins subbasins 12 12 12 100 n = 1,379 n = 669 n = 78 n = 1,379 n = 669 n = 78 o 11 11 11 90 o o EXPLANATION 10 o 10 10 x 80 n Number of sites o 9 9 o 9 Outlier detached x 70 x x x Outlier outside o 8 o 8 o 8 x o x x x Upper x 60 x 7 7 o 7 o x o x 75th percentile x o 6 o 6 6 50 o x x x x x o x x Median o o x 5 o 5 x 5 x 40 x o x o x x 25th percentile o x Channel slope, in percent o x x o Channel slope, in percent 4 ox 4 x 4 x x x x Local channel slope, in percent x x 30 Lower x x Buffered wetland, as percent of area x 3 x 3 3 x x x 20 2 2 2
o x 10 1 1 1 x
0 0 0 0
C. August withdrawal ratio D. Percent impervious cover Fish Fish sampling sampling SE Mass. MWI site SE Mass. MWI site SE Mass. hydrologic subbasins subbasins subbasins subbasins subbasins subbasins units 100 o o 100 o 100 o o o o o o o o o 90 o 90 90 o o o x o 80 x o 80 80 x o x o x o x o x o 70 x 70 70 x x o o x x o x x 60 x 60 60 x o x o x x o o x o o o 50 x 50 50 x x x o o o x x o x o 40 x 40 40 x o x x x x x x x x x o Impervious cover, in percent x x 30 30 30 x o o o x x x x x x x x x Median August withdrawal ratio, in percent x Average August withdrawal ratio, in percent x x x x x x x x x 20 20 20 x x
10 10 10
x x 0 0 0
Figure 25. Comparison of A, channel slope, B, percent wetland in a 787.4-foot (ft; 240-meter [m]) buffer, C, August withdrawal ratio, and D, percent impervious cover for Massachusetts water indicator (MWI) subbasins, fish sampling site subbasins, and southeastern Massachusetts (SE Mass.) hydrologic units and subbasins. 42 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass.
A. Percent forest B. Drainage area Fish Fish sampling sampling site SE Mass. site SE Mass. subbasins subbasins subbasins subbasins 100 400 o o o 90 350 o o 80 o o 300 EXPLANATION 70 o o Outlier detached x 250 o Outlier outside 60 Upper
o o 50 200 o 75th percentile o o o Median 40 o 150 o o
Drainage area, in square miles o o 25th percentile o 30 o o Forest, as percent of contributing area o Lower 100 o o o o 20 ox x x x x 50 x o 10 x o x x 0 0 C. Percent sand and gravel D. Undammed stream length E. Percent open water Fish Fish Fish sampling sampling sampling site SE Mass. site SE Mass. site SE Mass. subbasins subbasins subbasins subbasins subbasins subbasins 400 25 100 x x x o 90 x 350 x x x o 80 20 x x x x x 300 x x o 70 o x x o x 250 x o x 60 o x 15
o o o 200 50 o o o o 40 10 o 150 x x o x x x 30 Undammed stream length, in miles x o x x x 100 x Open water, as percent of contributing area o Sand and gravel, as percent of contributing area 20 5
50 10
o x 0 o 0 0
Figure 26. Comparison of A, percent forest, B, drainage area, C, percent sand and gravel, D, undammed stream length, and E, percent open water for fish sampling site subbasins and southeastern Massachusetts (SE Mass.) subbasins. Limitations 43 site, and southeastern Massachusetts subbasins, respectively. models used in this analysis is at a resolution suitable for Median values for impervious cover were 6.0 percent for regional studies (400 ft by 400 ft). The regional nature of Massachusetts water indicator subbasins, 4.2 percent for fish these models is useful in identifying local areas that may be sampling site subbasins, and about 11 percent for southeastern of concern to resource managers by incorporating production Massachusetts subbasins and hydrologic units. wells and other water-use data, aquifer geometry and water- The remaining five landscape characteristics for the transmitting properties, locations of surface water features subbasins for the 669 fish sampling sites (Armstrong and such as ponds and streams, and rates of recharge to the aquifer. others, 2011) and the subbasins delineated for this study are However, once an area of interest is identified from regional shown on the same graph (fig. 26). Percent forest (fig. 26A) model results, this regional resolution may not be suitable and drainage area (fig. 26B) are similar, but percent sand and to answer questions in areas of localized interest. To address gravel (fig. 26C), undammed stream length (fig. 26D), and more local issues, a subregional model that is hydraulically percent open water (fig. 26E) differ substantially between connected to the regional model but with a smaller, more the areas. Medians for percent forest were 70.1 and 55.8 for suitable spatial extent and discretization could be used. fish sampling site and southeastern Massachusetts subbasins, In this study, existing regional groundwater models respectively, whereas medians for drainage area were 7.4 and were used to investigate changes in surface-water features 3.5 mi2 for fish sampling site and southeastern Massachusetts (streamflows and pond levels) between predevelopment subbasins, respectively. In contrast, medians for percent conditions and pumping only and pumping with wastewater sand and gravel values were 16 and 100 for fish sampling return flow conditions. Although groundwater models provide site and southeastern Massachusetts subbasins, respectively. results for pond levels and streamflows, surface-water features The large sand and gravel aquifers found in southeastern generally are represented implicitly as hydraulic boundaries, Massachusetts compared with the rest of the Commonwealth and as such, these results are subject to limitations. account for this difference. Undammed reach lengths also Groundwater models are calibrated to both water levels and differed substantially, with medians of 38.7 and 1.7 miles for streamflows; the greater the number of calibration points with fish sampling site and southeastern Massachusetts subbasins, reliable data, the greater the confidence in the model results. respectively. Medians for open water as a percentage of Consequently, more uncertainty in simulated results exists in contributing area were 0.8 and 5.2 for fish sampling site and areas that lack, or have fewer, calibration points compared southeastern Massachusetts subbasins, respectively. with areas where more data are available; regional models Compared with the rest of Massachusetts, there are large may contain areas with relatively sparse calibration data. areas of southeastern Massachusetts where precipitation that Another potential limitation of using the existing models falls on the land surface will recharge groundwater and then to determine changes in streamflows and pond levels is the ultimately discharge directly to the coast without flowing representation of the artificial means that have been used into a stream. These are the land areas not covered by the to control pond levels (addition or removal of boards and hydrologic units shown in figure 5. Results of different other water level control structures), subsequent outflows analyses described in the reports of Walter and others (2004), to streams, and the length of time that a certain pond Walter and Whealan (2005), Masterson and others (2009), and elevation was maintained. Subsequent analysis of the model Masterson and Walter (2009) show similar areas of land that results shows that these outflow elevations are important to discharge directly to the coast in southeastern Massachusetts. downstream flows and to changes in those streamflows in The area of the Plymouth-Carver model represents a transition response to changing pumping and wastewater return flows. zone between the high topographic relief found to the north Pond levels and their outlet elevations were obtained from and west for the rest of Massachusetts and the low topographic topographic maps for each of the three modeled areas. At relief of Cape Cod. Southeastern Massachusetts also contains the regional scale, this resolution was considered acceptable, many groundwater subbasins that are isolated and do not but when comparing local streamflows that also may include directly touch another subbasin. A few of these areas exist outflows from ponds, this resolution may not be adequate. in the Plymouth-Carver region (for example, headwater Consequently, more uncertainty could be associated with subbasins SB–22, SB–24, SB–25, and SB–26), but many more streamflows derived as outflows from ponds with estimated exist on Cape Cod (for example, headwater subbasins SB–48, outlet elevations. SB–51, SB–67, and SB–77; figs. 5 and 6). These isolated The Silver Lake/Jones River outlet in Kingston (figs. 27 subbasins are separated by land areas that discharge directly to and 28) provides an example of where understanding the the coast. pond outlet flows to the head of the Jones River is critical to properly assess the potential effects of pumping on streamflow at the downstream gage. In this case, the Silver Lake pond Limitations elevation was estimated from a topographic map and used as the pond outlet stream elevation. Based on this elevation, Limitations arise in the use of a numerical model in the simulated pond contribution to long-term average which both time and space are discretized to simulate real- surface streamflow to the Jones River was about 8.4 ft3/s for world hydrologic processes. The size of the grid cells of the predevelopment conditions (fig. 29), which contributed to the 44 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass.
Cubic feet per second Pumping only Percent A. Existing model 70°48' 70°44' 70°48' 70°44' Pembroke Pembroke Duxbury Duxbury 42°1'30" Silver Silver Lake Lake 1 1
42° Jones River Jones River
2 2 simulated stream cell well
Kingston Kingston pond
Plympton Plympton
B. Alternative analysis with no pond outlet flow from Silver Lake to the Jones River Pembroke Pembroke Duxbury Duxbury 42°1'30" Silver Silver Lake Lake 1 1
42° Jones River Jones River
2 2
Kingston Kingston
Plympton Plympton
0 4,000 FEET EXPLANATION EXPLANATION 0 1 KILOMETER Streamflow change, in cubic feet Streamflow change, in percent—Negative per second—Negative values indicate a decrease values indicate a decrease in November in November streamflow in comparison streamflow in comparison to to predevelopment conditions predevelopment conditions 0.09 to -0.09 (no change) 0.09 to -0.09 (no change) -0.1 to -0.9 -0.1 to -0.9 -1 to -4.9 -1 to -1.9 -5 to -9.9 -2 to -3.9 -10 to -14.9 -4 to -5.9 -15 to -19.9 -6 to -7.9 -20 to -29.9 ≤ -8 -30 to -49.9 ≤ -50 2 Streamflow comparison site and identifier Pond outline Well
Figure 27. Simulated effect of pumping and percentage change on November streamflow compared with predevelopment conditions for A, the existing model and B, the alternative analysis with no pond outlet flow from Silver Lake to the Jones River area in southeastern Massachusetts. Limitations 45
Cubic feet per second Percent A. Existing model Pumping with wastewater return flows 70°48' 70°44' 70°48' 70°44' Pembroke Pembroke Duxbury Duxbury 42°1'30" Silver Silver Lake Lake 1 1
42° Jones River Jones River
2 2 simulated well stream cell
Kingston Kingston pond
Plympton Plympton
B. Alternative analysis with no pond outlet flow from Silver Lake to the Jones River
Pembroke Pembroke Duxbury Duxbury 42°1'30" Silver Silver Lake Lake 1 1
42° Jones River Jones River
2 2
Kingston Kingston
Plympton Plympton
0 4,000 FEET EXPLANATION EXPLANATION 0 1 KILOMETER Streamflow change, in cubic feet per second—Negative values indicate a decrease Streamflow change, in percent—Negative in November streamflow in comparison values indicate a decrease in November streamflow to predevelopment conditions in comparison to predevelopment conditions ≥ 2 ≥ 10 1 to 1.9 5.0 to 9.9 0.1 to 0.9 1.0 to 4.9 0.09 to -0.09 (no change) 0.1 to 0.9 0.09 to -0.09 (no change) -0.1 to -0.9 -0.1 to -0.9 -1 to -1.9 -1 to -4.9 -2 to -3.9 -5 to -9.9 -4 to -5.9 -10 to -14.9 -6 to -7.9 -15 to -19.9 -20 to -29.9 ≤ -8 -30 to -49.9 2 Streamflow comparison site ≤ -50 and identifier Pond outline Well
Figure 28. Simulated effect of pumping with wastewater return flows and percentage change on November streamflow compared with predevelopment conditions for A, the existing model and B, the alternative analysis with no pond outlet flow from Silver Lake to the Jones River area in southeastern Massachusetts. 46 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass. Pumping only Pumping with wastewater return flows EXPLANATION Predevelopment Pumping only Pumping with wastewater return flows Change in flow compared with predevelopment Cumulative downstream flow D N O S A J Site 2 J Result of predevelopment and pumping with wasterwater return flows is similar M A M F Streamflow comparison site 2 on figures 27 and 28 J 5 5 0 5 0 5 - - , the alternative analysis with no pond outlet flow from Silver Lake to Jones River 1 0 1 0 5 5 0 4 5 4 0 3 5 3 0 2 5 2 0 1 5 1 0 5 5 0 4 5 4 0 3 5 3 0 2 5 2 0 1 5 1 0 - - B Month D N O S A , existing model and A J J Site 1 M A M imulated November streamflow and change in compared with predevelopment conditions for two sites on S F Streamflow comparison site 1 on figures 27 and 28
A. Existing model B. Alternative analysis with no pond outlet flow from Silver Lake to the Jones River J 5 5 0 5 0
5 - - 1 0
5 5 0 4 5 4 0 3 5 3 0 2 5 2 0 1 5 1 0 1 0 5 5 0 4 5 4 0 3 5 3 0 2 5 2 0 1 5 1 0 - - Streamflow or change in streamflow, in cubic feet per second per feet cubic in streamflow, in change or Streamflow Figure 29. the Jones River from simulations of in southeastern Massachusetts. Plots show differences cumulative flow and change the Jones River with without outflow from Silver Lake. Locations of sites 1 and 2 are shown on figures 27 28. Limitations 47
37.1-ft3/s streamflow at the downstream gage (Masterson and regional groundwater models with incomplete historical others, 2009). Therefore, the assumption in the Plymouth- information to inform local questions. Also highlighted is the Carver regional modeling analysis was that about 22 percent importance of various types of measured data recorded over a of the total streamflow at the downstream gage (figs. 27 long period of time and historic data collection activities that and 28, streamflow comparison site 2) was derived from contribute to measured water level and streamflow datasets, pond flow into the river. When the simulated predevelopment among other things, that can be used to calibrate future streamflow then was compared with the streamflow under groundwater models. pumping with wastewater return flow conditions, the In addition to the Silver Lake/Jones River system in streamflow at the downstream gage decreased by about the Plymouth-Carver model area, other headwater pond/ 3.1 ft3/s, or about 8 percent, with 2.7 ft3/s (or about 87 percent) stream systems exist in the modeled areas of southeastern of that decrease occurring at the pond outlet in response to Massachusetts. Table 7 shows results of the alternative pumping at Silver Lake (Masterson and others, 2009). analysis where there was no contribution of headwater-pond To better understand the effect of contributions from outflow to the stream for selected subbasins in the Plymouth- ponds on streamflow alteration, an alternative analysis was Carver and western Cape model areas for steady-state, and conducted in which pond outlet flows to receiving streams January, April, August, and October streamflows. Three broad were excluded. For the alternative analysis of the Silver Lake/ categories of results were identified from this alternative Jones River system, changes in streamflows among the two analysis: (1) the pond outflow contributes greatly to the streamflow comparison sites on the Jones River were assessed downstream flow, (2) there is no outflow from the pond to the for November rather than for long-term average conditions. stream, and (3) the streamflow system is comparatively more November streamflows were compared because that was complex because of other ponds located within the course of the month that had the largest streamflow alteration for the the stream as well as infiltration of streamflow into the aquifer existing model between the two streamflow comparison sediments downstream of a pond (a losing stream). In these sites on the Jones River (fig. 29). For the existing model, headwater pond/stream systems, the results of the alternative the comparison between predevelopment and pumping with analysis were less conclusive. Two of the systems that showed wastewater return flow conditions indicates that the depletion the greatest difference in streamflow alteration when pond in the Jones River at the downstream gage (streamflow outflows were absent were the Billington Sea/Town Brook comparison site 2) is about 10 ft3/s or 26 percent of the total and Mashpee-Wakeby Pond/Mashpee River systems (figs. 18 (fig. 27); however, more than 80 percent of that reduction and 19; table 7). In contrast, the Island Creek Pond/Island (8.2 ft3/s) occurred at the pond outlet, highlighting the Creek and Lovells Pond/Little River systems had no pond importance of understanding the contribution of streamflow at outflow to the stream and, therefore, showed no change in the pond outlet to the stream for predevelopment conditions. the alternative analysis (figs. 18 and 19; table 7). Finally, the Given the uncertainty in model results because of the Halfway Pond/Agawam River system was an example of lack of data available to verify the simulated outflows from a system with greater complexity; this system had a lower the pond, the effects of pumping only and pumping with streamflow at the downstream outlet point of subbasin SB–17 wastewater return flows on the portion of the streamflows than at the pond outflow point because of infiltration of water not associated with pond outlet flows were evaluated for the from the stream into the aquifer. The alternative analysis alternative analysis. For the Jones River, predevelopment makes use of the models as they are currently documented, November streamflow at the downstream gage (streamflow but presents an alternative analysis of the simulated results for comparison site 2), not including the contribution from the areas downstream from ponds to address the uncertainty in pond, was 30.4 ft3/s (fig. 29). For the pumping only analysis, simulated predevelopment pond outlet flows. it was 29.2 ft3/s, and for the pumping with wastewater return In addition to uncertainties associated with calibration flow analysis, it was 30.3 ft3/s (fig. 29). Based on this analysis, and the use of the groundwater models to simulate complex the total depletion for the Jones River at the downstream gage pond/stream systems, model error associated with the for pumping with wastewater return flow conditions would be numerical solution can also exist. Model error is the 0.3 percent, compared with 22 percent when the pond flows collective term for differences, from a number of sources, are included (figs. 28 and 29). that arise between simulated and actual hydrologic conditions Streamflows at the downstream gage that include and (Walter and Whealan, 2005; Masterson and others, 2009). exclude pond outlet flows are presented in this report to Discretization, which is the size of the model cells, is one illustrate the extent to which streamflow alteration results component that can contribute to model error when the are affected by flow from the pond outlet. Had information model cell size is larger than the feature being simulated— on outflows and outlet elevation over time been available for example, a regional groundwater model area with a grid for the calibration period, this information could have been of uniformly sized cells at 400 ft by 400 ft, where streams incorporated into the model (for Silver Lake and other ponds) of width of 20 ft exist. In this analysis, a small number of at that time. However, the only information available was stream cells actually showed an increase in simulated stream streamflow at the downstream streamgage. This example flow under pumping only conditions when compared with underscores the uncertainties in simulated results from predevelopment conditions, which is unrealistic and indicative 48 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass. . * * 5.7 4.0 5.3 0.6 6.0 1.8 7.7 1.8 7.3 3.3 0.6 0.0 0.0 0.0 -5.5 -5.7 11.7 10.0 10.0 14.7 flow tions -72.5 -38.3 return Pump - condi - ing with /s 3 * * /s, cubic foot 5.6 9.9 3.8 4.6 0.4 5.6 9.9 1.7 7.2 1.7 6.8 3.2 0.4 0.0 0.0 0.0 0.0 3 ing -5.5 only 11.6 14.0 tions in ft -72.5 -31.1 Pump - condi - . ft - October streamflow, October streamflow, * * 5.8 4.1 5.7 0.6 6.8 1.8 7.8 1.8 7.4 3.3 0.6 0.0 0.0 0.0 -5.6 10.1 ment tions 10.1 12.2 15.6 velop - condi - -73.8 -42.3 -14.5 Prede * * 5.7 4.0 5.8 0.9 6.0 1.8 8.1 1.8 7.6 3.7 0.9 0.0 0.0 0.0 -5.6 -4.9 11.5 10.2 10.2 13.9 flow tions -70.9 -35.8 return Pump - condi - ing with /s * * 3 5.4 3.8 5.1 0.8 5.4 1.7 7.7 1.7 7.3 3.6 0.8 0.0 0.0 0.0 -5.7 -0.8 11.4 10.2 10.2 13.2 ing -70.9 -29.2 only tions in ft Pump - condi - August streamflow, August streamflow, * * 5.6 4.1 6.1 0.9 6.5 1.8 8.2 1.8 7.7 3.7 0.9 0.0 0.0 0.0 -5.7 11.9 10.3 10.3 14.9 -72.5 -40.1 -14.1 ment tions velop - condi - Prede - , stream reach followed by the number * * 5.5 1.8 2.5 2.5 9.9 5.4 1.8 0.0 0.0 -4.9 -9.6 11.0 16.3 10.8 12.4 18.0 17.2 18.5 10.4 flow tions -70.4 -49.7 -10.9 return Pump - condi - ing with /s 3 * * 5.3 1.6 2.3 2.3 9.6 5.4 1.6 0.0 0.0 ing -5.0 -9.6 only 11.5 16.2 10.4 10.2 18.0 17.1 17.9 10.1 tions in ft -70.4 -47.5 -10.4 Pump - condi - April streamflow, April streamflow, * * 5.5 2.5 2.0 2.5 5.4 2.0 0.0 0.0 -5.0 11.6 11.2 16.4 13.4 18.3 17.5 19.3 10.6 ment tions 10.0 velop - condi - -71.3 -51.6 -13.4 -10.5 Prede - * * 5.2 2.3 0.9 9.7 2.3 9.0 8.3 8.5 4.3 0.9 0.0 0.0 0.0 -5.1 14.2 10.8 14.2 15.7 17.8 flow tions -70.8 -48.6 -10.3 return Pump - condi - ing with /s 3 * * 5.0 2.2 0.8 9.2 2.2 8.5 7.7 8.1 4.2 0.8 0.0 0.0 0.0 ing -5.1 -9.3 only 14.1 10.2 14.1 15.6 17.2 tions in ft -70.9 -45.4 Pump - condi - January streamflow, January streamflow, Existing models * * 5.3 2.3 1.0 2.3 9.1 8.6 8.6 4.3 1.0 0.0 0.0 -5.2 -3.3 11.9 13.9 10.3 14.4 16.1 18.7 ment tions velop - condi - -50.5 -13.6 -71.8 Prede - * * 4.8 2.1 1.0 8.3 9.1 2.1 9.1 7.8 8.6 4.3 1.0 0.0 0.0 flow -5.2 -8.9 -4.5 tions 12.7 13.3 14.3 16.4 return Pump - condi - -45.0 -70.9 ing with , and pumping with wastewater return flow conditions for long-term average (steady state) /s 3 * * 4.6 2.0 0.9 7.6 8.3 2.0 8.7 7.1 8.2 4.2 0.9 0.0 0.0 ing -5.3 -8.1 -4.5 only 12.7 13.3 14.2 15.7 tions in ft -40.5 -70.9 Pump - condi - , western Cape model; s, stream segment followed by the number; r Alternative analysis with no contribution of headwater pond outflow to the stream * * 4.8 2.1 1.2 8.5 9.9 2.1 9.2 8.4 8.7 4.3 1.2 0.0 0.0 Steady state streamflow, Steady state streamflow, -5.3 -5.6 12.8 ment tions 13.5 14.7 17.3 velop - condi - -48.9 -13.7 -72.1 Prede - Percentage difference in streamflows between existing models and alternative analyses of cell ID Stream pc_s64r1 pc_s69r11 pc_s124r31 pc_s187r21 w_s11r25 pc_s27r4 pc_s27r4 pc_s64r1 pc_s69r11 pc_s124r31 pc_s187r21 w_s3r26 w_s8r22 w_s3r26 w_s8r22 w_s11r25 pc_s187r21 w_s3r26 w_s8r22 w_s11r25 pc_s27r4 pc_s64r1 pc_s69r11 pc_s124r31 2 2 2 ID 11 11 11 17 32 40 63 17 32 40 52 59 52 59 63 40 52 59 63 17 32 Sub - basin Stream name to South Meadow Brook to South Meadow Brook to South Meadow Brook Wankinco River Wankinco Agawam River Town Brook Town Island Creek Little River Unnamed tributary Unnamed tributary Wankinco River Wankinco Agawam River Brook Town Island Creek Coonamessett River Mashpee River Coonamessett River Mashpee River Little River Island Creek Coonamessett River Mashpee River Little River Unnamed tributary Wankinco River Wankinco Agawam River Town Brook Town Simulated streamflows for predevelopment, pumping only
Name of Pond Pond Pond headwater pond East Head Pond Halfway Pond Billington Sea Island Creek Pond Lovells Pond Kings Pond Kings Pond East Head Pond Halfway Pond Billington Sea Island Creek Pond Coonamessett Pond Mashpee/Wakeby Mashpee/Wakeby Coonamessett Pond Mashpee/Wakeby Mashpee/Wakeby Lovells Pond Island Creek Pond Coonamessett Pond Mashpee/Wakeby Mashpee/Wakeby Lovells Pond Kings Pond East Head Pond Halfway Pond Billington Sea Stream cell identification number (ID): pc, Plymouth-Carver model; w Table 7. Table April, August, and October conditions for the existing models alternative analysis with no pond outlet flow Plymouth-Carver western Cape model January, areas, southeastern Massachusetts. [Streams and ponds are shown in figures 2 3; subbasins 5 6. Cells marked with an asterisk (*) denote lower flow at outlet point due to infiltration of water from stream into aquifer per second] Summary 49 of a local model error. Where this occurred, the resulting basins in the rest of Massachusetts were also determined for streamflow values for pumping only conditions were set equal the 78 groundwater subbasins delineated in this study. to the predevelopment values; the result then was no change The pumping and wastewater return flow locations in streamflow between predevelopment and pumping only and rates used in this study are the same as those used in conditions. These stream cells were noted in the transient previously published studies. Steady-state simulations were shapefiles in field err_cfs with a value (greater than zero) used to evaluate long-term average effects of pumping and that is the difference between the predevelopment value and wastewater return flows on water levels and streamflows, and the erroneous value for pumping only conditions in cubic transient simulations were used to evaluate average monthly feet per second. Streamflow changes in these stream cells effects. The current pumping and wastewater return flow for pumping only conditions, therefore, would have greater conditions were for 2000 through 2005 for the Plymouth- uncertainty than in other stream cells. Compared with the Carver model and 2003 for the western and eastern Cape Cod total number of stream cells, this phenomenon occurred in models. Although these time periods do not exactly coincide, relatively few stream cells. The range of transient results in the difference was considered minor and was acceptable for the Plymouth-Carver model showed that this error occurred in this study. The net effect of pumping and wastewater return less than 1 percent of the stream cells in January, October, and flows on streamflows and pond levels varied by location and included no change in areas minimally affected by water December and about 6 percent of the stream cells in April. In use, decreases in areas affected more by pumping than by the western Cape model, this error occurred in about 1 percent wastewater return flows, or increases in areas affected more by of the stream cells in each month. In the eastern Cape model, wastewater return flows than by pumping. it occurred in about 2 percent of the stream cells for most Streams in southeastern Massachusetts are relatively months, with a peak of about 5 percent in November. small compared with those in the rest of the Commonwealth. Time periods for pumping in the models included 2000 Generally, streamflow magnitudes tended to decrease with through 2005 for Plymouth-Carver and 2003 for western and distance eastward on Cape Cod, whereas streamflows with eastern Cape Cod. Although these time periods do not exactly the largest magnitude occurred in streams in the Plymouth- coincide, this difference was considered a minor limitation and Carver region. Maximum simulated long-term average was acceptable for this project. It was beyond the scope of this predevelopment streamflows ranged from 13.1 cubic feet study to update each model for a coincident time period. per second (ft3/s) in the eastern Cape model to 68.8 ft3/s in the Plymouth-Carver model. For most of the groundwater subbasins in study area, simulated streamflows normalized Summary by subbasin area are about 2 cubic feet per second per square mile or less. Water use, such as withdrawals, wastewater return flows, Simulated alterations to long-term average streamflows and interbasin transfers, can alter streamflow regimes, water at subbasin outlets in response to pumping with wastewater quality, and the integrity of aquatic habitat and affect the avail- return flows ranged from a decrease (depletion) of 43.9 percent at an unnamed tributary to Salt Pond (Plymouth- ability of water for human and ecosystem needs. To provide Carver model) to an increase (surcharge) of 18.2 percent at the information needed to determine alteration of streamflows an unnamed tributary to Centerville River (western Cape and pond water levels in southeastern Massachusetts, the U.S. model). However, alterations were within 10 percent of Geological Survey, in cooperation with the Massachusetts predevelopment streamflows for most of the subbasins in the Department of Environmental Protection, conducted a study study area. In general, the relative effects of pumping and that made use of the existing groundwater models of the wastewater return flows typically were larger in the subbasins Plymouth-Carver region and western (Sagamore flow lens) with low streamflows than in the subbasins with high and eastern (Monomoy flow lens) Cape Cod. The main objec- streamflows. Depleted streamflows occurred more frequently tive of the study was to determine the location and magnitude than surcharged streamflows. Increases in streamflows in of changes (or alterations) in simulated streamflows and pond response to wastewater return flows were generally largest levels in response to pumping and wastewater return flows. in subbasins with a high density of septic systems or a Streamflow and pond-level alterations were calculated relative centralized wastewater treatment facility. to a predevelopment (no pumping or wastewater return flow) For average monthly conditions, streamflow alteration baseline condition for long-term average (steady-state) and results were similar spatially to results for long-term average average monthly (transient) conditions. Streamflow alterations conditions. However, differences in the extent of alteration were computed at the outlets of 78 groundwater subbasins by month were observed. Percentage streamflow depletions delineated in this study, and at the individual groundwater were larger during the low-streamflow months of August model cells used to represent the stream network in south- and October in most subbasins. Streamflow surcharges eastern Massachusetts. Pond-level alterations were computed were more variable by month, but also were larger during for each pond simulated in the study area. Selected landscape the low-streamflow months in most subbasins. For the characteristics computed for the topographically derived low-streamflow month of August, streamflow alterations 50 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass. ranged from a decrease of 100 percent (no streamflow Armstrong, D.S., Richards, T.A., and Levin, S.B., conditions) at Indian Brook in the Plymouth-Carver model 2011, Factors influencing riverine fish assemblages to an increase of 43.7 percent at an unnamed tributary to Salt in Massachusetts: U.S. Geological Survey Scientific Pond in the Plymouth-Carver model. However, simulated Investigations Report 2011–5193, 58 p. [Also available at alterations of average August streamflow under pumping and http://pubs.usgs.gov/sir/2011/5193/.] wastewater return flow conditions were within 10 percent of Barlow, P.M., 1997, Particle-tracking analysis of contributing predevelopment streamflows for most of the subbasins in the areas of public-supply wells in simple and complex flow study area. systems, Cape Cod, Massachusetts: U.S. Geological Survey The percentages of the total number of ponds affected by Water-Supply Paper 2434, 66 p. [Also available at pumping with wastewater return flow conditions under long- http://pubs.er.usgs.gov/publication/ofr93159.] term average conditions were 28 percent for the Plymouth- Carver model, 67 percent for the western Cape model, and Franke, O.L., Reilly, T.E., Pollock, D.W., and LaBaugh, J.W., 75 percent for the eastern Cape model. Pond-level alterations 1998, Estimating areas contributing recharge to wells: ranged from a decrease of 4.6 feet (ft) at Great South Pond Lessons from previous studies: U.S. Geological Survey in the Plymouth-Carver model to an increase of 0.9 ft at Circular 1174, 14 p. [Also available at http://water.usgs.gov/ Wequaquet Lake in the western Cape model. The magnitudes ogw/pubs/Circ1174/circ1174.pdf.] of monthly pond water level alterations were fairly consistent Fry, J.A., Xian, George, Jin, Suming, Dewitz, J.A., Homer, throughout the year. C.G., Yang, Limin, Barnes, C.A., Herold, N.D., and For both long-term average and monthly streamflows, Wickham, J.D., 2011, Completion of the 2006 national comparison of simulation results for pumping only and land cover database for the conterminous United States: pumping with wastewater return flows shows that enhanced Photogrammetric Engineering & Remote Sensing, v. 77, recharge resulting from wastewater return flows can either no. 9, p. 858–864, accessed April 26, 2013, at reduce the magnitude of streamflow depletion caused by http://www.mrlc.gov/nlcd2006.php. pumping or, less commonly, produce surcharged stream- flows that exceed predevelopment streamflows. Similarly Harbaugh, A.W., 2005, MODFLOW–2005, the U.S. for ponds, wastewater return flows can either reduce the Geological Survey modular ground-water model—The magnitude of decreases in pond levels caused by pumping ground-water flow process: U.S. Geological Survey or produce levels that exceed predevelopment levels. Thus, Techniques and Methods, book 6, chap. A16, [variously paged]. [Also available at http://pubs.usgs.gov/tm/2005/ wastewater return flows can have locally important effects tm6A16/.] on the extent of streamflow and pond-level alterations in southeastern Massachusetts. Harbaugh, A.W., Banta, E.R., Hill, M.C., and McDonald, Because multiple simulations were conducted over a M.G., 2000, MODFLOW–2000, the U.S. Geological Survey large geographic area, this study produced an extensive set of modular groundwater model—User guide to modularization simulation results. These results are available in appendixes 2 concepts and the groundwater flow process: U.S. Geological and 3 as geographic information system shapefiles and Survey Open-File Report 00–92, 121 p. [Also available at spreadsheets. ArcMap projects that contain the shapefiles http://pubs.usgs.gov/of/2000/0092/report.pdf.] are provided in appendixes 2 and 3. Appendix 2 contains Massachusetts Department of Environmental Protection, the results of all simulations (streamflow and pond-level 2014a, SWMI technical resources: Massachusetts alteration for all water-use conditions under steady-state and Department of Environmental Protection Web page, transient conditions), and appendix 3 contains the landscape accessed March 19, 2014, at http://www.mass.gov/eea/ characteristics for the groundwater subbasins. agencies/massdep/water/watersheds/sustainable-water- management-initiative-swmi.html. [Includes a link to the regression equation solver, at http://www.mass.gov/eea/ References Cited docs/dep/water/resources/n-thru-y/solver.xlsm.] Massachusetts Department of Environmental Protection, Archfield, S.A., Vogel, R.M., Steeves, P.A., Brandt, 2014b, SWMI technical resources: Massachusetts S.L., Weiskel, P.K., and Garabedian, S.P., 2010, The Department of Environmental Protection Web page, Massachusetts sustainable yield estimator—A decision accessed March 19, 2014, at http://www.mass.gov/eea/ support tool to assess water availability at ungaged sites agencies/massdep/water/watersheds/sustainable-water- in Massachusetts: U.S. Geological Survey Scientific management-initiative-swmi.html. [Includes a link to the Investigations Report 2009–5227, 41 p. plus CD–ROM. biological category statewide map, at http://www.mass.gov/ [Also available at http://pubs.usgs.gov/sir/2009/5227/.] eea/docs/dep/water/resources/a-thru-m/bc.pdf] References Cited 51
Massachusetts General Court, 2015, Massachusetts water Pollock, D.W., 1994, User’s guide for MODPATH/ management act: Massachusetts General Court Web page, MODPATH-PLOT, version 3; a particle tracking post- accessed August 18, 2015, at https://malegislature.gov/ processing package for MODFLOW, the U.S. Geological Laws/GeneralLaws/PartI/TitleII/Chapter21g. Survey finite-difference groundwater flow model: U.S. Massachusetts Office of Geographic Information, 2012, Geological Survey Open-File Report 94–464, 234 p. [Also MassGIS data—Dams: Massachusetts Office of Geographic available at http://pubs.er.usgs.gov/publication/ofr94464.] Information Web page, accessed May 2, 2013, at http://www.mass.gov/anf/research-and-tech/it-serv-and- Prudic, D.E., 1989, Documentation of a computer program to support/application-serv/office-of-geographic-information- simulate stream-aquifer relations using a modular, finite- massgis/datalayers/dams.html. difference, groundwater flow model: U.S. Geological Survey Open-File Report 88–729, 113 p. [Also available at Masterson, J.P., Carlson, C.S., and Walter, D.A., 2009, http://pubs.er.usgs.gov/publication/ofr88729.] Hydrogeology and simulation of groundwater flow in the Plymouth-Carver-Kingston-Duxbury aquifer system, Walter, D.A., and Masterson, J.P., 2011, Estimated hydrologic southeastern Massachusetts: U.S. Geological Survey budgets of kettle-hole ponds in coastal aquifers of Scientific Investigations Report 2009–5063, 110 p. southeastern Massachusetts: U.S. Geological Survey [Also available at http://pubs.er.usgs.gov/publication/ Scientific Investigations Report 2011–5137, 72 p. [Also sir20095063.] available at http://pubs.usgs.gov/sir/2011/5137/.] Masterson, J.P., and Walter, D.A., 2000, Delineation of ground-water recharge areas, western Cape Cod, Walter, D.A., Masterson, J.P., and Hess, K.M., 2004, Massachusetts: U.S. Geological Survey Water-Resources Groundwater recharge areas and travel times to pumped Investigation Report 00–4000, 1 sheet. [Also available at wells, ponds, streams, and coastal water bodies, Cape http://pubs.er.usgs.gov/publication/wri004000.] Cod, Massachusetts: U.S. Geological Survey Scientific Investigations Map I–2857, 1 sheet. [Also available at Masterson, J.P., and Walter, D.A., 2009, Hydrogeology and groundwater resources of the coastal aquifers of http://pubs.usgs.gov/sim/2004/2857/.] southeastern Massachusetts: U.S. Geological Survey Walter, D.A., and Whealan, A.T., 2005, Simulated Circular 1338, 16 p. [Also available at http://pubs.usgs.gov/ water sources and effects of pumping on surface and circ/circ1338/.] ground water, Sagamore and Monomoy flow lenses, Masterson, J.P., Walter, D.A., and LeBlanc, D.R., 1998, Cape Cod, Massachusetts: U.S. Geological Survey Delineation of contributing areas to selected public-supply Scientific Investigations Report 2004–5181, 85 p., wells, western Cape Cod, Massachusetts: U.S. Geological http://pubs.usgs.gov/sir/2004/5181/. Survey Water-Resources Investigations Report 98–4237, 45 p. [Also available at http://pubs.er.usgs.gov/publication/ Weiskel, P.K., Brandt, S.L., DeSimone, L.A., Ostiguy, wri984237.] L.J., and Archfield, S.A., 2010, Indicators of streamflow alteration, habitat fragmentation, impervious cover, and McDonald, M.G., and Harbaugh, A.W., 1988, A modular three-dimensional finite-difference groundwater flow water quality for Massachusetts stream basins: U.S. model: U.S. Geological Survey Techniques of Water- Geological Survey Scientific Investigations Report 2009– Resources Investigations, book 6, chap. A1, 586 p. [Also 5272, 70 p. plus CD–ROM. [Also available at available at http://pubs.usgs.gov/twri/twri6a1/.] http://pubs.usgs.gov/sir/2009/5272/.]
Appendix 1. Development of Transient Groundwater Models for Cape Cod
Appendix 2. Simulated Changes to Streamflows and Pond Levels
Appendix 3. Landscape Characteristics in Simulated Groundwater Contributing Areas to Streams
[ZIP files of shapefiles and spreadsheet files for appendixes 2 and 3 are available separately at http://dx.doi.org/10.3133/sir20155168.] 54 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass.
Appendix 1. Development of Transient Groundwater Models for Cape Cod
A sequence of models for Cape Cod (fig. 1–1) has existing transient hydrologic boundary conditions, storage been developed from previously published investigations. properties of the aquifer sediments, and hydraulic stresses, as The original versions of the western Cape (Sagamore flow documented in Walter and Whealan (2005). This combination lens) and eastern Cape (Monomoy flow lens) models were produced updated transient models of western and eastern documented in Walter and Whealan (2005). A subsequent Cape Cod. Finally, Walter and Masterson (2011) document the investigation by Walter and Masterson (2011) estimated most recent steady-state versions and this report documents hydrologic budgets for 425 ponds and modified the areas that the most recent transient versions of the western and eastern represented ponds in the steady-state models of Walter and Cape Cod models. Whealan (2005); modifications were made to more accurately To document the similarity of results between the match actual conditions. The modifications by Walter and existing transient versions of the western and eastern Cape Masterson (2011) include changes to the Layer-Property Cod models in Walter and Whealan (2005) and the transient Flow (LPF) package (Harbaugh and others, 2000) of the versions modified for this report, pond levels and streamflows U.S. Geological Survey’s three-dimensional finite-difference were compared. Three long-term streamflow monitoring sites groundwater model MODFLOW in areas of ponds to more located in the study areas were used to compare simulated accurately simulate the geometry of certain ponds and to streamflows: the Herring River in the eastern Cape model include additional ponds not previously represented, as well and the Quashnet River and Mill Creek in the western Cape as to the Streamflow-Routing (STR) package (Prudic, 1989) model (fig. 3). A discussion of the comparison of streamflow to more accurately represent the interaction of certain streams data collected in May 2002 and the agreement with long- with ponds. The steady-state models documented in Walter term mean and median streamflow estimates are available in and Masterson (2011) were used in this study; however, Walter and Whealan (2005, appendix 1). Walter and Whealan Walter and Masterson (2011) did not produce updated (2005) indicate that in the Herring River the long-term mean transient models. Because the areas that represented ponds and median flow values were 9.9 and 8.6 cubic feet per were more accurately simulated by the changes documented second (ft3/s), respectively, with a measured streamflow in in Walter and Masterson (2011), transient versions of these May 2002 of 7.7 ft3/s. These values compare to simulated May models would be better suited for the current analysis. In streamflow values of 7.0 ft3/s from Walter and Whealan (2005) brief, to incorporate the modifications made by Walter and and 9.0 ft3/s from the transient model modified for this report. Masterson (2011), the updated pond areas—essentially areas This difference of 2.0 ft3/s can be attributed to an increase in of infinite hydraulic conductivity—were combined with the flow out of Hinckleys Pond of 2.0 ft3/s, which was caused by
1 Walter and Whealan (2005) Steady state Transient
Modified
2 Walter and Masterson (2011) Steady state
Combined
3 This report Steady state Transient
Figure 1–1. The evolution of the western Cape (Sagamore flow lens) and eastern Cape (Monomoy flow lens) models of Cape Cod in southeastern Massachusetts. Appendix 1 55 the manner in which ponds were represented in Walter and were 7.3 and 7.2 ft3/s from Walter and Whealan (2005) and Masterson (2011). In the western Cape model, streamflow the transient model modified for this report, respectively. measured in May 2002 on the Quashnet River was 15.3 ft3/s, These comparisons show that the simulated streamflows were which was close to the long-term mean and median values of similar between the original and modified transient versions of 15.8 and 15.3 ft3/s, respectively (Walter and Whealan, 2005). the models. The simulated May streamflow on the Quashnet River of Simulated pond water levels from Walter and Whealan 17.2 ft3/s was the same in both Walter and Whealan (2005) and (2005) and this study (using the updated, transient version the transient model modified for this report. In Mill Creek, at of the Walter and Whealan [2005] model) were compared the outlet of Lower Shawme Lake, the measured streamflow for selected ponds: Coles Pond and Paddocks Pond from the of 6.3 ft3/s was similar to the mean and median streamflows eastern Cape model, and Ashumet Pond and Mary Dunn Pond of 6.4 ft3/s. The simulated May streamflows on Mill Creek from the western Cape model (fig. 1–2). These hydrographs
Western Cape (Sagamore) model Eastern Cape (Monomoy) model A. Ashumet Pond B. Coles Pond 45 5 44.5 4.5
44 4
43.5 3.5
43 3 42.5 2.5
42 2 41.5 1.5
41 1 C. Mary Dunn Pond D. Paddocks Pond 28 22
27.6 21.5 Water level, in feet 27 21
26.6 20.5
26 20
25.6 19.5
25 19
24.6 18.5
24 18 J F M A M J J A S O N D J F M A M J J A S O N D Month
EXPLANATION Walter and Whealan (2005) This report
Figure 1–2. Comparison of simulated pond levels between Walter and Whealan (2005) and the updated transient models (this report) for A, Ashumet Pond, B, Coles Pond, C, Mary Dunn Pond, and D, Paddocks Pond in southeastern Massachusetts. 56 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass. show that the largest monthly differences were 0.09 feet (ft) in June at Coles Pond; 0.36 ft in April at Paddocks Pond; a consistent 0.1 ft for most of the year at Ashumet Pond; and –0.08 ft in May at Mary Dunn Pond. Simulated seasonality and magnitude of pond levels compared favorably between the results of Walter and Whealan (2005) and the updated transient models used for this study. The model archive for this report will include the steady-state versions used in Walter and Masterson (2011) and the transient versions developed for this analysis.
References Cited
Harbaugh, A.W., Banta, E.R., Hill, M.C., and McDonald, M.G., 2000, MODFLOW–2000, the U.S. Geological Survey modular groundwater model—User guide to modularization concepts and the groundwater flow process: U.S. Geological Survey Open-File Report 00–92, 121 p. [Also available at http://pubs.usgs.gov/of/2000/0092/report.pdf.]
Masterson, J.P., Carlson, C.S., and Walter, D.A., 2009, Hydrogeology and simulation of groundwater flow in the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts: U.S. Geological Survey Scientific Investigations Report 2009–5063, 110 p. [Also available at http://pubs.er.usgs.gov/publication/ sir20095063.]
Prudic, D.E., 1989, Documentation of a computer program to simulate stream-aquifer relations using a modular, finite- difference, groundwater flow model: U.S. Geological Survey Open-File Report 88–729, 113 p. [Also available at http://pubs.er.usgs.gov/publication/ofr88729.]
Walter, D.A., and Masterson, J.P., 2011, Estimated hydrologic budgets of kettle-hole ponds in coastal aquifers of southeastern Massachusetts: U.S. Geological Survey Scientific Investigations Report 2011–5137, 72 p., http://pubs.usgs.gov/sir/2011/5137/.
Walter, D.A., and Whealan, A.T., 2005, Simulated water sources and effects of pumping on surface and ground water, Sagamore and Monomoy flow lenses, Cape Cod, Massachusetts: U.S. Geological Survey Scientific Investigations Report 2004–5181, 85 p. [Also available at http://pubs.usgs.gov/sir/2004/5181/.] Appendix 2 57
Appendix 2. Simulated Changes to Streamflows and Pond Levels
Simulated changes to streamflows are available in this includes 13 shapefiles—one shapefile for each month for analysis for each stream cell (individual model cell), and January through December and one for the steady-state simulated changes in pond levels are available for each pond. simulations—for each model area. Each of those 13 shapefiles The diagram in figure 2–1 graphically shows the complete contains the simulated cumulative streamflows for each monthly (January through December) and steady-state stream cell for predevelopment, pumping only, and pumping results that are available for pumping only and pumping with with wastewater return flow conditions, and the simulated wastewater return flow conditions for all streams at the outlets changes in streamflow due to pumping only and pumping of the subbasins, for individual stream cells, and for all ponds with wastewater return flow conditions in comparison to in the model areas. These results are in the shapefiles and predevelopment conditions in cubic feet per second and spreadsheet files of this appendix (available for download at percentage change. Because each shapefile includes results http://dx.doi.org/10.3133/sir20155168). Use of the shapefiles for all conditions, the same shapefiles appear four times in in the accompanying ArcMap project will allow close the ArcMap project, and each appearance displays a different inspection of results for individual streams and ponds. The field or result. Three spreadsheet tables are also included predevelopment, pumping only, and pumping with wastewater that contain the same results as the shapefiles. The dataset return flow streamflow and pond water level results from which changes were calculated are included in the shapefiles for changes in simulated pond levels is similar to that for and spreadsheet files. The metadata contained within each streamflows except that changes due to pumping only and for shapefile provide additional information on shapefile contents. pumping with wastewater return flows are provided in feet and Streamflow output from model simulations includes the that the same shapefiles appear only two times in the ArcMap outflow component from each stream cell for predevelopment, project for display purposes. pumping only, and pumping with wastewater return flow Additional ancillary data are also included with the conditions in cubic feet per day. datasets. Other geographic information system shapefiles The ArcMap project included in this appendix contains included as ancillary data are locations of streamflow all of the shapefiles for changes in simulated streamflows and monitoring sites and the outline of the overall extent of each pond levels. The dataset for changes in simulated streamflows groundwater model area. 58 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass.
Results of groundwater model simulations for changes to streamflows and pond water levels: sir20155168_appendix2_gis.zip Folder: ..\Appendix2\GIS_and_spreadsheets_streams_and_ponds\ 1 Shapefiles in ArcMap project: 2 SEMass_streams_and_ponds.mxd Spreadsheets in folder: \tables_spreadsheets\ Display of simulated streamflow changes due to:
Average PC Annual W E [The same 13 shapefiles for each model Change, in area appear four times in the ArcMap cubic feet Monthly: PC project for display purposes. January The same results are also in one Pumping only per second through W spreadsheet for each model area.] December E [The same files appear again to show different results] PC Annual W flow_difference_Plymouth_Carver.xlsx E flow_difference_West_Cape.xlsx Change, as flow_difference_East_Cape.xlsx Percent Monthly: PC January through W December E
PC Annual W E Change, in cubic feet Monthly: PC January Pumping with per second through W EXPLANATION wastewater return flows December E Model area PC PC = Plymouth_Carver Annual W W = Western_Cape E Change, as E = Eastern_Cape Percent Monthly: PC January through W December E
Display of simulated pond level changes due to: Average [The same 13 shapefiles for each model PC area appear two times in the ArcMap Annual W project for display purposes. E Change, in The same results are also in one spreadsheet for each model area.] feet Monthly: PC January Pumping only through W December E pond_level_difference_Plymouth_Carver.xlsx [The same files appear again pond_level_difference_West_Cape.xlsx to show different results] PC pond_level_difference_East_Cape.xlsx Annual W E Change, in feet Monthly: PC January 3 Spreadsheets in folder: \pond_hydrographs\ through W Plymouth_Carver_hydrographs.xlsx Pumping with December E West_Cape_hydrographs.xlsx wastewater return flows East_Cape_hydrographs.xlsx
Figure 2–1. The shapefiles and spreadsheet files that accompany this report and represent the simulated changes in streamflows and pond levels in the Plymouth-Carver, western Cape, and eastern Cape model areas in southeastern Massachusetts. Appendix 3 59
Appendix 3. Landscape Characteristics in Simulated Groundwater Contributing Areas to Streams
This appendix includes the shapefiles and spreadsheet cells that correspond to the stream subsections or lengths files (available for download athttp://dx.doi.org/10.3133/ along a stream between outlet points from which the areas sir20155168) that contain results of the landscape of the hydrologic units were obtained, the locations of the characteristic determinations for the contributing areas streamflow monitoring sites from the original studies, and the (subbasins and hydrologic units). The diagram in figure 3–1 outline of the overall extent of each groundwater model area. graphically shows the names of the files in this appendix. The ArcMap project included in this appendix contains The procedure used to delineate the groundwater subbasins all of the shapefiles for the landscape characteristics. The is discussed in the “Development of Contributing Areas” dataset for the landscape characteristics of the groundwater section of this report. Ancillary data are also included with contributing areas includes two shapefiles, one group of the datasets. Additional attributes in the files include the area shapefiles, and two tables. One shapefile contains the and originating groundwater model, the simulated long-term 61 headwater subbasins and includes the landscape values average predevelopment streamflows at the outlets of the provided in table 3 of this report. The group of shapefiles subbasins and hydrologic units, and simulated long-term consists of one shapefile for each of the 17 subbasins and average streamflows normalized by the subbasin area. Other includes the landscape values provided in table 3. Another geographic information system shapefiles included as ancillary shapefile contains the percent impervious cover values data include a polygon file of the model cells that correspond determined for the 78 hydrologic units that are also provided to the outlets of the contributing area (subbasin and [or] in table 4. hydrologic unit), a polygon file of the pond and stream 60 Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Mass.
Landscape characteristics of simulated groundwater contributing areas to streams:
sir20155168_appendix3_gis.zip Shapefiles in ArcMap project in folder: \Appendix3\ GIS_and_tables_groundwater_contributing_areas\ SEMass_GIS_groundwater_contributing_areas.mxd
Subbasins (78 areas):
Headwater subbasins (61 areas): Plymouth_Carver Western_Cape Table3_SEMass_headwater_subbasins.shp Eastern_Cape
Subbasins (17 areas):
Individual shapefiles for each subbasin in folder Table_3_subbasins
Plymouth_Carver Western_Cape Eastern_Cape
subbasin_3.shp subbasin_53.shp subbasin_75.shp subbasin_4.shp subbasin_57.shp subbasin_79.shp subbasin_5.shp subbasin_60.shp subbasin_7.shp subbasin_71.shp subbasin_8.shp subbasin_12.shp subbasin_18.shp subbasin_30.shp subbasin_36.shp Simulated results also shown in table 3 subbasin_37.shp subbasin_39.shp in this report Hydrologic units (78 areas): Plymouth_Carver Western_Cape Table4_SEMass_hydrologic_units_impervious_cover.shp Eastern_Cape
Simulated results also shown in table 4 in this report
Figure 3–1. The shapefiles and spreadsheet files that accompany this report and represent the landscape characteristics for the groundwater contributing areas to streams in the Plymouth-Carver, western Cape, and eastern Cape model areas in southeastern Massachusetts. For more information concerning this report, contact: Director, New England Water Science Center U.S. Geological Survey 10 Bearfoot Road Northborough, MA 01532 [email protected] or visit our Web site at: http://newengland.water.usgs.gov
Publishing support by: The Pembroke Publishing Service Center. Carlson and others—Simulated Responses of Streams and Ponds to Groundwater Withdrawals and Wastewater Return Flows in Massachusetts—SIR 2015–5168 ISSN 2328-0328 (online) http://dx.doi.org/10.3133/sir20155168