Estimated Water Use and Availability in the 

Pawtuxet and Quinebaug River Basins, 

Rhode Island, 1995–99

By Emily C. Wild and Mark T. Nimiroski

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with the Rhode Island Water Resources Board

Scientific Investigations Report 2006–5154
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

P. Patrick Leahy, Acting Director

U.S. Geological Survey, Reston, Virginia: 2007

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Suggested citation:

Wild, E.C., and Nimiroski, M.T., 2007, Estimated water use and availability in the Pawtuxet and Quinebaug River Basins,

Rhode Island, 1995–99: U.S. Geological Survey Scientific Investigations Report 2006–5154, 68 p.
iii

Contents

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Purpose and Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Previous Investigations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Climatological Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

The Pawtuxet River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Land Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Pawtuxet River Subbasins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Minor Civil Divisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

The Quinebaug River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Estimated Water Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

New England Water-Use Data System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Public Water Supply and Interbasin Transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Domestic Water Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Public-Supply Use in the Pawtuxet and Quinebaug River Basins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Self-Supply Use in the Pawtuxet and Quinebaug River Basins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Commercial and Industrial Water Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Public-Supply Use in the Pawtuxet River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Self-Supply Use in the Pawtuxet and Quinebaug River Basins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Agricultural Water Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Return Flow and Interbasin Transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Site-Specific Return Flow in the Pawtuxet River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Aggregate Return Flow in the Pawtuxet and Quinebaug River Basins . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Interbasin Transfers in the Pawtuxet River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Estimated Water Availability in the Summer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Pawtuxet River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Quinebaug River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Water Budget . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Pawtuxet River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Quinebaug River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Selected References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
iv

Figures 

1. Map showing towns and climatological stations in the Pawtuxet River Basin, central 

Rhode Island, and Quinebaug River Basin, western Rhode Island . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2–3. Diagrams showing: 

2. The hydrologic cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3. The components of water use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4–10. Maps showing:

4. Subbasins in the Pawtuxet and Quinebaug River Basins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

5. Aquifers and selected production wells for the subbasins in the Pawtuxet and Quinebaug 

River Basins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

6. The 8-, 10-, and 12-digit Watershed Boundary Dataset delineations for the Pawtuxet and 

Quinebaug River Basins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

7. Scituate Reservoir Complex subbasin with selected partial-record stream-gaging stations 

and surficial deposits, Pawtuxet River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

8. Stream-gaging stations, Rhode Island Pollutant Discharge Elimination System sites, and 

wastewater-treatment plants associated with the Pawtuxet and Quinebaug River Basins . . 16

9. The Quinebaug River Basin in western Rhode Island, northeastern Connecticut, and 

south-central Massachusetts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

10. Public water-supply districts associated with the Pawtuxet River Basin and in the northern 

Narragansett Bay area, Rhode Island . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

11–16. Diagrams showing:

11. Johnston Water District interconnections, purchases, distribution, exports, and estimated 

water uses in the Pawtuxet River Basin, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

12. Kent County Water Authority withdrawals, interconnections, purchases, distribution, 

exports, and estimated water uses, central Rhode Island, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . 28

13. Providence Water Supply Board A, withdrawals, interconnections, distribution, and 

estimated water uses, central Rhode Island; and B, retail distribution, exports, and 

estimated water uses, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

14. Warwick Water Department interconnections, purchases, distribution, exports, and 

estimated water uses, central Rhode Island, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

15. Public-supply withdrawals and estimated exports from the Pawtuxet River Basin, 

1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

16. Estimated public wastewater collection, discharge, and estimated exports from the 

Pawtuxet River Basin, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

17–18. Graphs showing:

17. Estimated water availability for June, July, August, and September from sand and 

gravel deposits for the subbasins in the Pawtuxet and Quinebaug River Basins

for the A, 50th percentile; B, 50th percentile for the 7-day, 

10-year low-flow scenario; and C, 50th percentile for the Aquatic Base Flow scenario . . . . . . 54

18. Estimated water availability for June, July, August, and September from till deposits for

the subbasins in the Pawtuxet and Quinebaug River Basins for the 

A, 50th percentile; B, 50th percentile for the 7-day, 10-year low-flow scenario; and 

C, 50th percentile for the Aquatic Base Flow scenario . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

19. Maps showing the water withdrawal-to-availability ratios in A, June; B, July; C, August; and 

D, September for the subbasins in the Pawtuxet and Quinebaug River Basins at the 

50th percentile for the 7-day, 10-year low-flow scenario . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
v

Tables

1. Summary of National Oceanic and Atmospheric Administration climatological stations and data 

pertinent to the Pawtuxet River Basin, central Rhode Island, and to the Quinebaug River Basin, 

western Rhode Island, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2. Total town populations by subbasin for 1990, estimated populations for 1995–99, and estimated 

populations on public and self-supply and on public and self-disposal in the Pawtuxet and Quinebaug 

River Basins, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3. Town land area and land-use area by category in the subbasins of the Pawtuxet and Quinebaug River 

Basins, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

4. Land-use area and percentage of land-use area by major public water-supply district for the 

subbasins in the Pawtuxet River Basin study area and areas outside of the Pawtuxet River 

Basin, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

5. Defined subbasins in the Pawtuxet and Quinebaug River Basin study areas 

compared to the 10-digit and 12-digit Natural Resources Conservation Service Watershed 

Boundary Dataset (2003). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

6. Summary of total town land area, land area in the Pawtuxet and Quinebaug River Basins, 

total 1990 town populations and estimated 1995–99 populations, and land-use area 

by category in the Pawtuxet and Quinebaug River Basins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

7. Withdrawals by major public water-supply districts in and outside the subbasins of 

the Pawtuxet River Basin, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

8. Minor public water suppliers by subbasin in the Pawtuxet and Quinebaug River Basins, 

1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

9. Ground-water and surface-water withdrawals by town and subbasin in the Pawtuxet and 

Quinebaug River Basins, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

10. Average withdrawals and purchases for the Kent County Water Authority for June, July, 

August, and September, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

11. Withdrawals, discharges, retail sales, and wholesale purchases for the Providence Water 

Supply Board system in June, July, August, and September, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

12. Estimated water use by town and subbasin in the Pawtuxet and Quinebaug River Basins, 

1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

13. Estimated consumptive water use by town and subbasin in the Pawtuxet and Quinebaug River 

Basins, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

14. Estimated water use for each 2-digit Standard Industrial Classification code by town in the 

Pawtuxet and Quinebaug River Basins, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

15. Estimated public- and self-disposed domestic, commercial, industrial, and metered return flow

by subbasin in the Pawtuxet and Quinebaug River Basins, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

16. Return flows by subbasin for the Rhode Island Pollutant Discharge Elimination System sites 

in the Pawtuxet River Basin, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

17. Return flow from wastewater-treatment facilities within and outside of the Pawtuxet River 

Basin, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

18. Summary of estimated water withdrawals, imports, exports, use, consumptive use, and return 

flow in the Pawtuxet River Basin, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

19. Summary of estimated water withdrawals, imports, exports, use, consumptive use, and return 

flow in the Quinebaug River Basin, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

20. U.S. Geological Survey stream-gaging stations and minimum streamflows used in the analysis 

of water availability in the Pawtuxet and Quinebaug River Basins, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . 48

21. Summer gross yields for the index stream-gaging stations used in the water-availability 

analysis in the Pawtuxet and Quinebaug River Basins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
vi

22. Estimated gross yields; gross yields minus the 7-day, 10-year low flow; and gross yields 

minus the Aquatic Base Flow per unit area for the two index stations used to determine

water availability for June, July, August, and September in the Pawtuxet and Quinebaug River 

Basins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

23. Estimated ground-water availability and total availability for June, July, August, and 

September in the Pawtuxet River Basin, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

24. Average water withdrawals for June, July, August, and September in the subbasins of the 

Pawtuxet River Basin, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

25. Summary of water withdrawal-to-availability ratios for June, July, August, and September 

in the Pawtuxet River Basin, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

26. Estimated gross yield; gross yield for the 7-day, 10-year low-flow scenario; and gross yield for 

the Aquatic Base Flow scenario for June, July, August, and September in the Quinebaug River 

Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

27. Average water withdrawals for June, July, August, and September in the towns in the 

Quinebaug River Basin, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

28. Summary of water withdrawal-to-availability ratios for June, July, August, and September

in the Quinebaug River Basin, 1995–99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

29. Average water budget by subbasin for the Pawtuxet River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

30. Average water budget for the Quinebaug River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Conversion Factors, Vertical Datum, 

Abbreviations, and Acronyms 

Temperature is given in degrees Fahrenheit (°F), which can be converted to degrees Celsius (°C) 

by the following equation:

°C=(°F-32)/1.8

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD88). 

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD83).

To convert water use and availability data to cubic feet per second, multiply million gallons per 

day by 1.5466.

Multiply By To obtain

acre 4,047 square meter (m2)

acre 0.4047 hectare (ha)

foot (ft) 0.3048 meter (m)

square foot (ft2) 0.09290 square meter (m2)

square foot per day (ft2/d) 0.09290 square meter per day (m2/d)

gallons per day (gal/d) 0.003785 cubic meter per day (m3

/d)

mile (mi) 1.609 kilometer (km)

million gallons per day (Mgal/d) 3,785 cubic meters per day (m3/d)

million gallons per day per square mile 1,462.1 cubic meter per day per square kilometer

(Mgal/d/mi2

) (m3/d/km2)

square mile (mi2

) 2.590 square kilometer (km2)
vii

Abbreviations and Acronyms

7Q10 7-day, 10-year low flow

ABF Aquatic Base Flow

GIS Geographic Information Systems

HUC Hydrologic Unit Code

IWR-MAIN Institute of Water Resources, Municipal and Industrial Needs System

KCWA Kent County Water Authority

MCD Minor Civil Division

NCDC National Climatic Data Center

NEWUDS New England Water-Use Data System

NHD National Hydrography Dataset

NOAA National Oceanic and Atmospheric Administration

NRCS Natural Resources Conservation Service

ProvWater Providence Water Supply Board

RIDEM Rhode Island Department of Environmental Management

RIEDC Rhode Island Economic Development Corporation

RIGIS Rhode Island Geographic Information System

RIPDES Rhode Island Pollutant Discharge Elimination System

SCS Soil Conservation Service

SIC Standard Industrial Classification

USDA U.S. Department of Agriculture

USEPA U.S. Environmental Protection Administration

USGS U.S. Geological Survey

WSO Weather Station Observatory

WWTF Wastewater-Treatment Facility

Estimated Water Use and Availability in the Pawtuxet and 

Quinebaug River Basins, Rhode Island, 1995–99

By Emily C. Wild and Mark T. Nimiroski

Abstract

Water availability became a concern in Rhode Island during a drought in 1999, and an investigation was needed to assess 

demands on the hydrologic system from withdrawals during 

periods of little to no precipitation. The low water levels during 

the drought prompted the U.S. Geological Survey and the 

Rhode Island Water Resources Board to begin a series of studies on water use and availability in each drainage area in Rhode 

Island for 1995–99. The study area for this report, which 

includes the Pawtuxet River Basin in central Rhode Island 

(231.6 square miles) and the Quinebaug River Basin in western 

Rhode Island (60.97 square miles), was delineated as the 

surface-water drainage areas of these basins. 

During the study period from 1995 through 1999, two 

major water suppliers withdrew an average of 71.86 million gallons per day (Mgal/d) from the Pawtuxet River Basin; of this 

amount, about 35.98 Mgal/d of potable water were exported to 

other basins in Rhode Island. The estimated water withdrawals 

from minor water suppliers were 0.026 Mgal/d in the Pawtuxet 

River Basin and 0.003 Mgal/d in the Quinebaug River Basin. 

Total self-supply withdrawals were 2.173 Mgal/d in the Pawtuxet River Basin and 0.360 Mgal/d in the Quinebaug River 

Basin, which has no public water supply. Total water use 

averaged 18.07 Mgal/d in the Pawtuxet River Basin and 0.363 

Mgal/d in the Quinebaug River Basin. Total return flow in the 

Pawtuxet River Basin was 30.64 Mgal/d, which included about 

12.28 Mgal/d that were imported from other basins in Rhode 

Island. Total return flow was 0.283 Mgal/d in the Quinebaug 

River Basin. 

During times of little to no recharge in the form of precipitation, the surface- and ground-water flows are from storage 

primarily in the stratified sand and gravel deposits; water also 

flows through the till deposits, but at a slower rate. The ground 

water discharging to the streams during times of little to no 

recharge from precipitation is referred to as base flow. The 

PART program, a computerized hydrograph-separation application, was used to analyze the data collected at two selected 

index stream-gaging stations to determine water availability on 

the basis of the 75th, 50th, and 25th percentiles of the total base 

flow; the base flow for the 7-day, 10-year low-flow scenario; 

and the base flow for the Aquatic Base Flow scenario for both 

stations. The index stream-gaging stations used in the analysis 

were the Branch River at Forestdale, Rhode Island (period of 

record 1957–1999) and the Nooseneck River at Nooseneck, 

Rhode Island (period of record 1964–1980). A regression equation was used to estimate unknown base-flow contributions 

from sand and gravel deposits at the two stations. The base-flow 

contributions from sand and gravel deposits and till deposits at 

the index stations were computed for June, July, August, and 

September within the periods of record, and divided by the area 

of each type of surficial deposit at each index station. These 

months were selected because they define a period when there 

is usually an increased demand for water and little to no precipitation. The base flows at the stream-gaging station Branch 

River at Forestdale, Rhode Island were lowest in August at the 

75th, 50th, and 25th percentiles (29.67, 21.48, and 13.30 

Mgal/d, respectively). The base flows at the stream-gaging station Nooseneck River at Nooseneck, Rhode Island were lowest 

in September at the 75th percentile (3.551 Mgal/d) and lowest 

in August at the 50th and 25th percentiles (2.554 and 1.811 

Mgal/d).

The base flows per unit area for the index stations were 

multiplied by the areas of sand and gravel and till in the studyarea subbasins to determine the amount of available water for 

each scenario. The water availability in the Pawtuxet River 

Basin at the 50th percentile ranged from 126.5 Mgal/d in 

August to 204.7 Mgal/d in June, and the total gross water availability for the 7-day, 10-year low-flow scenario at the 50th percentile ranged from 112.2 Mgal/d in August to 190.4 Mgal/d in 

June. The Scituate Reservoir safe yield was 83 Mgal/d in all 

scenarios. Water availability in the Quinebaug River Basin 

ranged from 13.94 Mgal/d in August to 30.53 Mgal/d in June at 

the 50th percentile. The total gross water availability for the 

7-day, 10-year low-flow scenario at the 50th percentile ranged 

from 14.26 Mgal/d in August to 42.69 Mgal/d in June.

Because water withdrawals and use are greater during the 

summer than other times of the year, water availability in June, 

July, August, and September was compared to water withdrawals in the basin and subbasins. The ratios of water withdrawn to 

water available were calculated for the 75th, 50th, and 25th percentiles for the subbasins; the closer the ratio is to 1, the closer 

the withdrawals are to the estimated water available, and the 

less net water is available. Withdrawals in July were higher than 

in the other summer months in both basins. In the Pawtuxet 

River Basin, the ratios were close to 1 in July for the estimated 

gross yield (from sand and gravel and from till and from the Scituate Reservoir safe yield), 7-day, 10-year low-flow scenario, 

and Aquatic Base Flow scenario at the 75th percentile and in 
2 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

August for all three scenarios at the 50th and 25th percentiles. 

In the Quinebaug River Basin, the ratios were close to 1 in 

August for the estimated gross yield; 7-day, 10-year low-flow 

scenario; and Aquatic Base Flow scenario. 

A long-term water budget was calculated for 1941 through 

1999 to identify and assess the basin and subbasin inflow and 

outflows for the Pawtuxet and Quinebaug River Basins. The 

water withdrawals and return flows used in the budget were 

from 1995 through 1999. Inflow was assumed to be equal to 

outflow; total inflows and outflows were 574.9 Mgal/d in the 

Pawtuxet River Basin and 148.4 Mgal/d in the Quinebaug River 

Basin. Precipitation and return flow were 95 and 5 percent of 

the estimated inflows to the Pawtuxet River Basin, respectively. 

Precipitation was 100 percent of the estimated inflow to the 

Quinebaug River Basin; return flow was less than 1 percent of 

the inflow. Evapotranspiration, streamflow, and water withdrawals were 46, 41, and 13 percent, respectively, of the estimated outflows in the Pawtuxet River Basin. Evapotranspiration and streamflow were 49 and 51 percent, respectively, of the 

estimated outflows in the Quinebaug River Basin. Water 

withdrawals were less than 1 percent of outflows in the 

Quinebaug River Basin. 

Introduction

Water availability became a concern to the State of Rhode 

Island during a drought in 1999, and an investigation was 

needed to assess water use and availability in the state, including the Pawtuxet and Quinebaug River Basins (fig. 1). During 

the summer of 1999, the average precipitation at the Kingston, 

RI, climatological station for June was only about 0.05 in., compared to the 30-year (1971-2000) long-term average precipitation of 3.936 in. for June. Because precipitation is a key component of surface-water runoff and ground-water infiltration 

(fig. 2), the rain deficiency caused a period of little to no 

recharge. As a result, ground-water levels and streamflows 

dropped below their long-term averages throughout Rhode 

Island. 

To address water use and availability concerns in Rhode 

Island, the U.S. Geological Survey (USGS) began a series of 

nine water use and availability investigations in different basins 

for 1995–99 in cooperation with the Rhode Island Water 

Resources Board (RIWRB), which serves as a water-sourcing 

agency to ensure future water availability for residential growth 

and economic development for all Rhode Islanders (Rhode 

Island Water Resources Board, 2003). The purpose of the nine 

studies was to determine the relations between the water-use 

components (fig. 3) and the components of the hydrologic cycle 

(surface and ground water) during periods of little to no 

recharge. This particular study focused on the Pawtuxet and 

Quinebaug River Basins in central and western Rhode Island, 

respectively. Results of the Pawtuxet and Quinebaug River 

Basins studies and additional studies of other basins in or adjacent to Rhode Island will be used to compare water demands to 

water availability for times of little to no recharge, particularly 

during June, July, August, and September.

Purpose and Scope

This report identifies the water-use components and estimates water use and availability in the Pawtuxet and Quinebaug 

River Basins for calendar years 1995–99. To estimate water 

use, data for the components of water use were collected by 

basin and subbasin for the towns in the Pawtuxet and 

Quinebaug River Basins. The information and data on water 

withdrawals, use, and discharges were organized and retrieved 

by using the New England Water-Use Data System 

(NEWUDS) for the study period. The report presents the results 

of the calculated water availability for the Pawtuxet and 

Quinebaug River Basins for periods of little to no recharge by 

determining ground-water discharge during streamflowrecession periods and by using the previously published safe 

yield for the Scituate Reservoir (Weston, 1990). Because there 

are no major public water suppliers, wastewater collections, or 

interbasin transfers in the Quinebaug River Basin, discussion of 

these topics pertains only to the Pawtuxet River Basin. Water 

budgets, however, are presented for both basins. These budgets 

summarize the components of the hydrologic cycle on the basis 

of the long-term period of record for both basins (59 years) and 

selected water-use components for the study period.

Previous Investigations

The USGS has been collecting streamflow data from partial and continuous stream-gaging stations in the Pawtuxet 

River Basin for more than 63 years, and has been monitoring 

ground-water levels for more than 59 years. The data collected 

in the basin and its subbasins have been used for numerous 

hydrologic studies. Many studies have focused on the groundwater and surface-water resources and the water quality in the 

Pawtuxet River Basin and its subbasins. The Pawtuxet River 

Basin occupies areas within the Chepachet, Clayville, Coventry 

Center, Crompton, East Greenwich, East Killingly, Georgiaville, Hope Valley, North Scituate, Providence, Slocum, and 

Thompson USGS quadrangles. These quadrangles are published in the form of detailed thematic maps in reports describing the surficial geology (Feininger, 1962; Power, 1957; Richmond, 1953; Robinson, 1961; Smith, 1955; Smith, 1956a; and 

Smith, 1956b) and bedrock geology (Barosh, 1976; Dixon, 

1974; Moore, 1958; Moore, 1963; Power, 1959; Quinn, 1951; 

Quinn, 1952; Quinn, 1959; Richmond, 1952). The Quinebaug 

River Basin occupies areas within the East Killingly, Oneco, 

Oxford, Thompson, and Voluntown USGS quadrangles. The 

surficial geology of the basin is described in quadrangle-map 

reports by Feininger (1965b) and Harwood and Goldsmith 

(1971b), and the bedrock geology in similar reports by Dixon 

(1974), Feininger (1965a), Harwood and Goldsmith (1971a), 

and Moore (1963). 
Introduction 3

PROVIDENCE CO

PROVIDENCE CO

KENT CO

KENT CO

BRISTOL CO

BRISTOL CO 

NEWPORT CO 

NEWPORT CO

WASHINGTON CO

WASHINGTON CO

1

1

95

195

295

95

146

10

1

1

CONNECTICUT

RHODE ISLAND

MASSACHUSETTS

RHODE ISLAND

CONNECTICUT

MASSACHUSETTS

WOONSOCKET

NORTH

SMITHFIELD BURRILLVILLE

GLOCESTER SMITHFIELD

JOHNSTON

SCITUATE

CRANSTON

BARRINGTONWARREN

BRISTOL

PORTSMOUTH

MIDDLETOWN

LITTLE

COMPTON

NEWPORT

JAMESTOWN

COVENTRY

WEST

GREENWICH

EAST GREENWICH

WEST WARWICK

WARWICK

EXETER

RICHMOND

CHARLESTOWN

HOPKINTON

NORTH KINGSTOWN

SOUTH KINGSTOWN

FOSTER

CUMBERLAND

LINCOLN

PAWTUCKET NORTH PROVIDENCE

EAST

PROVIDENCE

PROVIDENCE

TIVERTON

WESTERLY

Potowomut

Kingston

PAWTUXET RIVER BASIN

QUINEBAUG

RIVER

BASIN

SOUTH COASTAL DRAINAGE BASIN

WESTPO

RT

BASIN

PAWCATUCK RIVER BASIN

WOONASQUATUCKET 

RIVER BASIN

BLACKSTONE RIVER BASIN

QUINEBAUG

RIVER

BASIN

NARRAGANSETT

BAY BASIN

MOSHASSUCK

RIVER BASIN

TEN MILE

RIVER

BASIN

41o30'

41o

45'

71o

45' 71o30' 71o15'

42o

00'

0 5 10 KILOMETERS

0 5 10 MILES

EXPLANATION

MAJOR BASIN BOUNDARY

SUBBASIN BOUNDARY

WITHIN PAWTUXET BASIN

CLIMATOLOGICAL STATION

WITH RAIN GAGE

Base from U.S. Geological Survey and Rhode Island Geographic Information System digital data, 1:24,000 

Lambert conformal conic projection. 1983 North American datum

Figure 1. Towns and climatological stations in the Pawtuxet River Basin, central Rhode Island, and Quinebaug River Basin, 

western Rhode Island.
4 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

Ground-Water Infiltration

THE HYDROLOGIC CYCLE

Surface Water

(Rivers and Ponds)

Ground-Water Discharge

(Base Flow)

Ground Water

(Bedrock or Stratified Sand and 

Gravel Aquifers)

Direct Runoff

Atmosphere

Land Surface

PrecipitationPrecipitation

EvapotranspirationEvapotranspiration

Figure 2. The hydrologic cycle. (Modified from U.S. Geological Survey, 2004). 
Introduction 5

 

(Ground Water

and Surface Water)

Water Withdrawals

Water Purification

Nonaccount 

Water Use

Water Distribution

Inflow and

Infiltration

 Wastewater 

Collection

WastewaterTreatment

Facility

(Ground Water

and Surface Water)

Return Flow

Consumptive 

Use (Domestic, Industrial,

Commercial, and 

Agricultural)

Nonaccount 

Water Use

Water Use

Figure 3. The components of water use.
6 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

The Rhode Island Water Resources Geologic Bulletin 

report series provides information about well records, lithologic 

logs, water-quality assessments, hydrologic characteristics of 

the surficial deposits (till and stratified sand and gravel deposits), and water-table altitudes. The Geologic Bulletin reports 

used in this assessment include Allen (1956), Bierschenk 

(1959), Hahn (1961), Richmond and Allen (1951), Roberts and 

Brashears (1945), and Roberts and Halberg (1945). The Rhode 

Island Water Resources Ground-Water Map report series provides information about bedrock contours, water-table altitudes, well locations, and till and stratified sand and gravel 

deposits. Ground-water maps used in this assessment include 

Allen and others (1959), Bierschenk and Hahn (1959), Hahn 

(1959), Hahn and Hansen (1961), Hansen (1962a, 1962b), 

Johnson (1962), Mason and Hahn (1960), and Pollock (1960). 

Details about partial-record stations can be found in the USGS 

annual data report series (Socolow and others, 2001), in studies 

of the Scituate Basin (Breault and others, 2000; and Nimiroski 

and Waldron, 2002), and in a recent summary of stream-gaging 

stations and ground-water monitoring wells (Zarriello and 

Socolow, 2003). Limited data about ground water (Allen, 1953; 

Allen and Lang, 1957; Kliever, 1995; Lang, 1961) and surface 

water (Allen, 1953) are available for the Quinebaug River Basin 

in Rhode Island.

In addition to studies pertaining to surficial deposits in the 

basin and subbasins, water-use data for the Pawtuxet and 

Quinebaug River Basins have been published in statewide 

assessments (Craft and others, 1995; Horn, 2000; Horn and 

Craft, 1991; and Medalie, 1996). Previous investigations in this 

series of USGS water use and availability studies (Barlow, 

2003; and Nimiroski and Wild, 2005) contain additional information on wholesale purchases for districts within the Blackstone, Woonasquatucket, and Moshassuck River Basins from 

the Pawtuxet River Basin. The public water suppliers submit 

individual water-supply management plans to the RIWRB as a 

part of the state’s Water Supply Systems Management Plan. 

Information on public disposal was collected (oral and written 

communication) from wastewater assessments that have been 

completed and submitted to the Rhode Island Department of 

Environmental Management (RIDEM), Office of Water 

Resources.

Climatological Setting

The National Oceanic and Atmospheric Administration 

has been publishing precipitation and temperature data from the 

climatological stations in Rhode Island for more than 100 years 

(fig. 1). Data have been collected continuously at some of the 

climatological stations, whereas other stations have had 

months-long breaks in operation. The breaks in the record make 

it difficult to assess accurately the annual precipitation and 

trends in the average monthly precipitation and temperature 

through the period of record. 

Precipitation data for the climatological stations at Kingston, Rhode Island, on the University of Rhode Island (URI) 

campus; the Providence Weather Station Observatory (WSO) at 

the airport in Warwick, Rhode Island; at North Foster, Rhode 

Island; and at North Scituate, Rhode Island, were compiled by 

using the monthly and annual summaries published in the series 

“Climatological Data New England” (National Oceanic and 

Atmospheric Administration, 2000), and are presented in table 

1. These data were used to calculate components of water use 

and the hydrologic cycle. Statewide, total annual precipitation 

is about 47.98 in., the average annual temperature is about 

50.08°F (National Oceanic and Atmospheric Administration, 

2000 and 2002), and the climate is humid and temperate. For 

June, July, August, and September, long-term (1971–2000) 

trends in average precipitation differ substantially from trends 

during the study period (table 1). During the study period, the 

total annual precipitation was about 48.92 in., and the average 

annual temperature was about 50.96°F. The Kingston climatological station has the longest precipitation record (1889–2005) 

of all of the Rhode Island climatological stations. The total 

annual precipitation at the Kingston climatological station for 

the study period was 53.11 in., and the average monthly precipitation for the summer ranged from 2.728 in. (July) to 4.474 in. 

(September). In addition to precipitation data from the stations 

operated by the National Oceanic and Atmospheric Administration, data from a network of precipitation stations operated by 

the Providence Water Supply Board (ProvWater) were used in 

calculating water budgets for 1941–99 (Providence Water Supply Board, written commun., 2000). 

The Pawtuxet River Basin

The Pawtuxet River Basin in central Rhode Island (fig. 4) 

has a land area of about 231.6 mi2. Thirteen Rhode Island towns 

are partially within the study area. In 1990, the basin population 

was about 196,121, and the estimated population during the 

study period was 194,963 (table 2). The Pawtuxet River Basin 

is mostly hilly, with higher altitudes in the northwest. For this 

study, the basin was divided into four subbasins—the Scituate 

Reservoir Complex, North Branch Pawtuxet, South Branch 

Pawtuxet, and Northeastern Pawtuxet subbasins (fig. 4)— 

which are based on the surface-water drainage areas. Aquifers 

for this study were defined as areas of stratified sand and gravel 

deposits with more than 40 ft of saturated thickness. One principal aquifer, the Mishnock aquifer, referred to as a groundwater reservoir in Rhode Island, is completely within the basin 

(fig. 5). The Providence-Warwick aquifer extends north to 

south along the coast of Narragansett Bay; the aquifer crosses 

the basin near the confluence of the Pawtuxet River with Narragansett Bay (fig. 5). Because limited data are available pertaining to the ground-water flow in this aquifer, the basin’s surface-water divides were used for water-use and availability 

calculations. Losses from ground-water underflow within the 

defined surface-water drainage areas were considered negligible for this study. 
The Pawtuxet River Basin 7

Table 1. Summary of National Oceanic and Atmospheric Administration climatological stations and data pertinent to the Pawtuxet 

River Basin, central Rhode Island, and to the Quinebaug River Basin, western Rhode Island, 1995–99.

[Locations of climatological stations are shown on fig. 1. Climatological data are from monthly and annual summaries from the National Climate Data Center of 

the National Oceanic and Atmospheric Administration, 1971–2000 (National Oceanic and Atmospheric Administration, 2000a and b). WSO, weather station observatory; °F, degrees Fahrenheit; in., inches]

Climatological station

Period of 

record 

[study period]

June July August September Annual

Average total precipitation (in.)

Kingston, RI 1971–2000

[1995–99]

3.936

4.106

3.308

2.728

4.400

4.356

4.163

4.474

51.79

53.11

North Foster, RI1 1975–2000

[1995–99]

3.921

4.256

3.690

2.904

4.723

3.002

3.899

4.976

51.74

52.59

North Scituate, RI2 1970–74 4.126 2.908 3.488 5.104 53.75

Providence WSO Airport, 

Warwick, RI

1971–2000

[1995–99]

3.382

3.414

3.169

1.978

3.904

3.190

3.704

4.014

46.46

43.91

Woonsocket, RI 1971–2000

[1995–99]

3.653

3.506

3.666

3.932

4.279

3.126

4.093

4.290

50.05

51.58

Average temperature (°F)

Kingston, RI 1971–2000

[1995–99]

65.63

66.50

71.06

71.88

69.91

70.32

62.72

63.74

49.94

50.91

Providence WSO Airport, 

Warwick, RI

1971–2000

[1995–99]

67.65

68.20

73.37

74.14

71.88

72.08

63.99

64.74

51.13

51.84

1

North Foster station is missing precipitation data (September 1981, March 1982, July 1982, February 1983, March 1983, and January 1985), and therefore 

these data were not included in the monthly averages. No total annual precipitation data were available for the years 1981, 1982, 1983, and 1985.

2

North Scituate station was offline from October through December 1974, and therefore these data were not included in the monthly averages. No average total

annual precipitation was calculated for 1974.

Land Use

Land-use areas were calculated by merging the Rhode 

Island Geographic Information Systems (RIGIS) land-use coverages with the subbasin-boundary coverages. Land-use area 

was used as a tool to aggregate commercial, industrial, and agricultural water-use estimates by town, subbasin, and basin (table 

3). If categorical data were available from the public-supply district, water use was disaggregated by subbasin on the basis of 

land-use area in the public-supply district (table 4). Land-use 

areas not within public-supply districts were assumed to be selfsupplied. 

Pawtuxet River Subbasins 

The surface-water-flow boundaries were used for assessing water use and determining water availability for the summer 

in the basin (fig. 4) because data on ground-water movement 

along the currently defined surface-water delineations are limited. Based on the surface-water-drainage boundaries, about 

29.5 percent of the surficial geology in the Pawtuxet River 

Basin is stratified sand and gravel deposits. The thickness of the 

sand and gravel deposits is greater at the confluence of the Pawtuxet River Basin with Narragansett Bay, mainly because of the 

Providence-Warwick aquifer.

The USGS subbasin boundaries delineated for the study 

area are similar to the cataloging units defined in the Watershed 

Boundary Dataset (WBD) delineated by the Natural Resources 

Conservation Service (NRCS) in 2003 (table 5). The WBD used 

the standards for delineations of the boundaries that were established by the Federal Geographic Data Committee in 2002. The 

WBD cataloging units are compared visually to the areas used 

for this study in figure 6. The main spatial difference between 

them is that the smaller drainage areas determined by the WBD 

are grouped together by segments for this study. Naming conventions are another difference between the study subbasins 

and the WBD 10-digit and WBD 12-digit cataloging units (table 

5, fig. 6). The Pawtuxet River Basin is one of the WBD 10-digit 

cataloging areas within the USGS 8-digit Hydrologic Unit Code 

(HUC) area for the Narragansett Bay Basin.
8 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

Table 2. Total town populations by subbasin for 1990, estimated populations for 1995–99, and estimated populations on public and selfsupply and on public and self-disposal in the Pawtuxet River Basin, central Rhode Island, and in the Quinebaug River Basin, western 

Rhode Island, 1995–99.

[Shaded areas are basin totals. Total populations in Rhode Island, 1990, from Rhode Island Geographic Information System (1991). Estimated 1995–99 population from the Rhode Island Economic Development Corporation (2001). --, not applicable]

Towns

Population Estimated 1995–99 population

1990 Estimated

1995–99

Supply Disposal

Public Self Public Self

Pawtuxet River Basin

Scituate Reservoir Complex Subbasin

Cranston 144 142 97 45 16 126

Foster 2,455 2,509 100 2,409 -- 2,509

Glocester 2,799 2,815 -- 2,815 -- 2,815

Johnston 978 971 432 539 41 930

Scituate 7,832 8,006 431 7,575 238 7,768

Smithfield 91 90 -- 90 -- 90

Subbasin total 14,832 14,533 1,301 13,232 540 13,993

North Branch Pawtuxet Subbasin

Coventry 3,822 3,999 3,500 499 309 3,691

Cranston 1,047 1,031 701 330 114 916

Scituate 1,676 1,713 901 812 135 1,578

West Warwick 6,036 5,986 5,952 34 5,526 460

Subbasin total 12,581 12,729 11,054 1,675 6,084 6,645

South Branch Pawtuxet Subbasin

Coventry 25,627 26,816 20,753 6,063 3,307 23,509

East Greenwich 49 50 31 19 3 47

Exeter 367 398 4 394 -- 398

Foster 213 218 -- 218 -- 218

Scituate 281 287 -- 287 -- 287

Warwick 20 20 20 -- 8 12

West Greenwich 2,062 2,330 742 1,588 19 2,311

West Warwick 12,866 12,759 12,684 75 12,177 582

Subbasin total 41,485 42,878 34,234 8,644 15,514 27,364

Northeastern Pawtuxet Subbasin

Cranston 68,683 67,611 66,627 984 60,603 7,008

Johnston 13,100 13,014 10,913 2,101 7,110 5,904

Providence 25,417 23,957 23,957 -- 23,957 --

Warwick 17,349 17,061 17,054 7 11,560 5,501

West Warwick 3,207 3,180 3,039 141 3,024 156

Subbasin total 127,756 124,823 121,590 3,233 106,254 18,569

Basin total 196,121 194,963 168,179 26,784 128,392 66,571

Quinebaug River Basin

Burrillville 524 514 -- 514 -- 514

Coventry 1,552 1,569 40 1,529 -- 1,569

Exeter 75 81 -- 81 -- 81

Foster 1,648 1,684 -- 1,684 -- 1,684

Glocester 643 647 -- 647 -- 647

West Greenwich 41 46 -- 46 -- 46

Basin total 4,483 4,541 40 4,501 -- 4,541
The Pawtuxet River Basin 9

Pawtuxet River

WOONSOCKET

NORTH SMITHFIELD

BURRILLVILLE

GLOCESTER

SMITHFIELD

JOHNSTON

SCITUATE

CRANSTON

BARRINGTON WARREN

BRISTOL

MIDDLETOWN

JAMESTOWN

COVENTRY

WEST GREENWICH

EAST

GREENWICH

WEST WARWICK

WARWICK

EXETER

RICHMOND

NORTH KINGSTOWN

FOSTER

CUMBERLAND

LINCOLN

PAWTUCKET NORTH

PROVIDENCE

EAST PROVIDENCE

PROVIDENCE

WARWICK

0 5 KILOMETERS

0 5 MILES

41o30'

41o

45'

42o

00'

71o

45' 71o30'

Base from U.S. Geological Survey and Rhode Island Geographic Information System digital data, 1:24,000,

Lambert conformal conic projection. 1983 North American datum

NA

R

RAGANSETT

BAY

Ponaganset

Reservoir

Moswansicut Pond Regulating Pond

Westconnaug

Reservoir

Flat River

Reservoir

Barden Reservoir Scituate Reservoir

Flat River

Big River

SCITUATE RESERVOIR 

COMPLEX 

NORTHEASTERN 

PAWTUXET 

NORTH BRANCH

PAWTUXET

SOUTH BRANCH

PAWTUXET

MASSACHUSETTS

CONNECTICUT

MAJOR BASIN BOUNDARY

SUBBASIN BOUNDARY

WITHIN PAWTUXET BASIN

EXPLANATION

PAWTUXET RIVER BASIN

QUINEBAUG

RIVER

BASIN

QUINEBAUG

RIVER

BASIN

41o45'

71o

45' 71o30'

41o

30'

42o

00'

0 10 MILES

0 10 KILOMETERS

INDEX MAP OF

RHODE ISLAND

Block Island

STUDY

AREA

Figure 4. Subbasins in the Pawtuxet River Basin, central Rhode Island, and the Quinebaug River Basin, western Rhode Island.
10 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

WOON

NORTH

SMITHFIELD

BURRILLVILLE

GLOCESTER

SMITHFIELD

JOHNSTON

SCITUATE

COVENTRY

WEST

GREENWICH

EAST

GREENWI

WEST

WARWIC

FOSTER

SCITUATE RESERVOIR 

COMPLEX

NOR

P

NORTH BRANCH

PAWTUXET

SOUTH BRANCH

PAWTUXET

PAWTUXET RIVER BASIN

QUINEBAUG

QUINEBAUG

RIVER

BASIN

CONNECTICUT

A

B,C,D

E

Mishnock

aquifer

41o

45'

42o

00'

71o

45' 71

1

2

3

4

5

6

7

8

10 9

SOCKET

CRANSTON

BARRINGTON

WARREN

BRISTOL

MIDDLETOWN

CH

K

WARWICK

EXETER

RICHMOND

NORTH

KINGSTOWN

CUMBERLAND

LINCOLN

PAWTUCKET

NORTH

PROVIDENCE

EAST

PROVIDENCE

PROVIDENCE

THEASTERN 

AWTUXET 

RIVER

BASIN

MASSACHUSETTS

F

1

A

EXPLANATION

 Major production well—Letter 

 refers to data in table 7. 

 See table 7 for well-field description.

Minor production well—Number 

 refers to data in table 8.

 See table 8 for well description.

AQUIFER 

(GROUND-WATER RESERVOIR)

SAND AND GRAVEL DEPOSITS

TILL AND BEDROCK

MAJOR BASIN BOUNDARY

PAWTUXET BASIN (highlighted blue)

QUINEBAUG BASIN (highlighted grey)

SUBBASIN BOUNDARY

PRODUCTION WELLS

Providence-Warwick 

aquifer

HAP 

aquifer

0 5 KILOMETERS

0 5 MILES

41o30'

o

30' 71o

15'

Base from U.S. Geological Survey and Rhode Island Geographic Information System digital data (1988, 1997a), 1:24,000,

Lambert conformal conic projection. 1983 North American datum

Figure 5. Aquifers and selected production wells for the subbasins in the Pawtuxet and Quinebaug River Basins, central and 

western Rhode Island. [HAP, Hunt-Annaquatucket-Pettaquamscutt]
The Pawtuxet River Basin 11

The Scituate Reservoir Complex subbasin (94.11 mi2

drainage area) is in the western section of the Pawtuxet River 

Basin. The towns in the subbasin include Cranston, Foster, Glocester, Johnston, Scituate, and Smithfield (fig. 4). The Scituate 

Reservoir Complex subbasin is a headwater subbasin defined 

by the Gainer Dam embankment at the confluence with the 

North Branch Pawtuxet River. The complex includes the drainage areas for five reservoirs — the Ponaganset, Barden, Westconnaug, Regulating, and Moswansicut Reservoirs — which 

drain into the drainage area of the Scituate Reservoir (fig. 7), 

and comprises three 12-digit cataloging units defined by the 

WBD (fig. 6 and table 5). The Ponaganset River flows southeast 

from the Ponaganset Reservoir dam and into the Barden Reservoir. Hemlock Brook flows east into Barden Reservoir, which 

drains to the Scituate Reservoir at the confluence of Swamp 

Brook. Just south of the Barden Reservoir confluence, the 

Westconnaug Brook flows from the Westconnaug Reservoir 

into the Scituate Reservoir. In the northern part of the Scituate 

Reservoir Complex subbasin, Peeptoad, Huntinghouse, and 

Rush Brooks flow into the Regulating Reservoir. In the northeastern corner of the Scituate Reservoir Complex subbasin, 

drainage from the Moswansicut Reservoir flows west into the 

Regulating Reservoir. Other tributaries to the Scituate Reservoir include Brandy Brook from the east, Cork Brook from the 

north, Kent Brook from the east, Spruce Brook from the north, 

Quonapaug Brook from the east, and Wilbur Hollow Brook 

from the southwest. Although no defined aquifers are in the Scituate Reservoir Complex subbasin, about 17.4 percent of the 

glacial deposits are stratified sand and gravel deposits (figs. 5 

and 7). One continuous stream-gaging station (fig. 8), the Ponaganset River at South Foster, Rhode Island (01115187), has a 

period of record of more than 8 years, and the surficial deposits 

in the area upstream of the stream-gaging station are about 15 

percent sand and gravel. The USGS has been collecting surfacewater data from partial-record stations within the Scituate Reservoir Complex subbasin in cooperation with ProvWater for 

about 10 years (fig. 7). 

The North Branch Pawtuxet subbasin (14.09 mi2 drainage 

area) is the central section of the Pawtuxet River Basin. The 

towns in the subbasin include Coventry, Cranston, Scituate, and 

West Warwick (fig. 4). Land areas and land-use areas by category for towns and major public water suppliers are summarized in tables 3 and 4, respectively. The North Branch Pawtuxet River flows southeast from Gainer Dam. Although the 

North Branch Pawtuxet subbasin has no defined aquifer, the 

area of the subbasin is about 12 percent sand and gravel (fig. 5); 

these deposits are the source of water for some self-supply 

users. One discontinued stream-gaging station in the subbasin 

(fig. 8), Pawtuxet River at Fiskeville, Rhode Island (01115500), 

has a period of record of more than 20 years. The surficial 

deposits in the area upstream of the Fiskeville station are about 

12 percent sand and gravel, which is about the same as the percentage of sand and gravel deposits for the North Branch 

Pawtuxet subbasin.

Table 3. Town land area and land-use area by category in the

subbasins of the Pawtuxet River Basin, central Rhode Island, and 

in the Quinebaug River Basin, western Rhode Island, 1995–99.

[Shaded areas are basin totals. Land-use areas were estimated by using the coverage from the Rhode Island Geographic Information System (1995a).

mi2, square mile; <0.001, value not included in totals; --, not applicable]

Land Land-use area by category (mi2

)

Town area

(mi2

)

Commer- Indus- Agriculcial trial tural

Pawtuxet River Basin

Scituate Reservoir Complex Subbasin

Cranston 0.461 -- -- 0.095

Foster 28.95 0.170 0.042 .950

Glocester 16.39 .066 -- 1.023

Johnston 1.941 .033 .002 .175

Scituate 46.33 .174 .009 1.604

Smithfield

Subbasin total

.032 -- -- .003

94.11 0.443 0.053 3.850

North Branch Pawtuxet Subbasin

Coventry

Cranston

3.917

3.159

0.029

.001

0.062

.005

0.123

.892

Scituate 5.493 .014 .019 .538

West Warwick

Subbasin total

1.525 .093 .080 .035

14.09 0.137 0.166 1.588

South Branch Pawtuxet Subbasin

Coventry

East Greenwich

37.32

.140

0.575

--

0.284

--

0.985

--

Exeter 3.247 .008 -- .133

Foster 2.902 -- -- .083

Scituate 2.967 -- -- .172

Warwick .043 .001 -- .002

West Greenwich 23.10 .187 .038 .775

West Warwick

Subbasin total

2.958 .247 .144 .017

72.68 1.018 0.466 2.167

 Northeastern Pawtuxet Subbasin

Cranston 24.56 1.141 1.155 1.622

Johnston 14.60 .508 .269 .971

Providence 2.952 .279 .395 --

Warwick 7.140 1.014 .874 .058

West Warwick

Subbasin total

Basin total

1.460 .054 .020 .031

50.71 2.996 2.713 2.682

231.6 4.594 3.398 2.682

Quinebaug River Basin

Burrillville 8.595 -- -- 0.047

Coventry

Exeter

20.30

1.432

0.023

--

0.009

--

1.284

--

Foster 20.09 .077 -- 1.746

Glocester 9.703 .027 .037 .278

West Greenwich

Basin total

.853 -- -- .006

60.97 0.127 0.046 3.361
12 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99 Table 4. Land-use area and percentage of land-use area by major public water-supply district for the subbasins in the Pawtuxet River Basin study area and areas outside of the Pawtuxet River Basin, central Rhode Island, 1995–99. [Land-use areas for the water-supply districts were estimated by using the coverages from the Rhode Island Geographic Information System (1995a, b). mi2

, square mile; --, not applicable]

Major public water supplier

 Basin (and subbasin) 

where water is withdrawn or

major supplier from which 

water is purchased wholesale

Total land

area in

Pawtuxet

River Basin

(mi

2

)

Land-use area by category in the

Pawtuxet River Basin (mi2

)

Total land area

outside

Pawtuxet River 

Basin

(mi2

)

Land-use area by category outside of the 

Pawtuxet River Basin (mi2

)

Commercial Industrial

Agricultural Commercial Industrial

Agricultural

Cranston Water District Providence Water Supply Board 7.712 0.104 0.224 0.691 -- -- -- --Johnston Water District Providence Water Supply Board 8.241 .133 .208 .598 0.031 -- -- --Kent County Water Authority Pawtuxet (South Branch

Pawtuxet) and West Narragansett Bay (Hunt) 

24.33 1.274 .577 .514 21.04 1.202 0.541 0.819

Providence Water Supply

Board

Pawtuxet (Scituate Reservoir 

Complex)

19.34 1.642 1.369 .386 24.99 2.635 1.527 .114

Warwick Water Department Providence Water Supply Board;

Kent County Water Authority

6.035 .815 .852 -- 19.36 .895 .137 .802

Basin totals 65.66 3.968 3.230 2.189 65.42 4.732 2.205 1.735

Major public water supplier

 Basin (and subbasin) 

where water is withdrawn or

major supplier from which 

water is purchased wholesale

Total 

percentage 

of

land use in 

Pawtuxet 

River Basin

Percentage of land use in the

Pawtuxet River Basin

Total

percentage of 

land use 

outside 

Pawtuxet River 

Basin

Percentage of land use outside of the 

Pawtuxet River Basin

Commercial Industrial

Agricultural Commercial Industrial

Agricultural

Cranston Water District Providence Water Supply Board 100.0 100.0 100.0 100.0 -- -- -- --Johnston Water District Providence Water Supply Board 99.63 100.0 100.0 100.0 0.370 -- -- --Kent County Water Authority Pawtuxet (South Branch

Pawtuxet) and West Narragansett Bay (Hunt) 

53.63 51.45 51.61 45.97 46.37 48.55 48.39 54.03

Providence Water Supply

Board

Pawtuxet (Scituate Reservoir 

Complex)

43.63 38.39 47.27 77.20 56.37 61.61 52.73 22.80

Warwick Water Department Providence Water Supply Board;

Kent County Water Authority

23.77 47.66 86.15 -- 76.23 52.34 13.85 100.0
The Pawtuxet River Basin 13

Pawtuxet 0109000406

01100001

01090004

011000010301

011000010302

011000010502

011000010501

011000010503

011000010601

010900040601

010900040603

010900040602

010900040607

010900040609

010900040606

010900040605

010900040604

010900040608

QUINEBAUG

PAWTUXET

Upper Fivemile

River

Lower Fivemile

River

Upper Pachaug River

Upper Moosup

River

Lower Moosup

 River

Quaduck Brook

Regulating and 

Moswansicut Reservoirs

Ponaganset and

 Barden Reservoirs

Scituate and Westconnaug

Reservoirs

North Branch

 Pawtuxet River

South Branch

 Pawtuxet River

Big River 

Flat River

Pawtuxet River

Main Stem

Pocasset River 

0 5 KILOMETERS

0 5 MILES

Base from U.S. Geological Survey, Connecticut Map and Geographic Information Center, 

and Rhode Island Geographic Information System data sets

Rhode Island state plane, 5176 fipzone

1983 North American datum

Watershed Boundary Dataset from

Natural Resources Conservation Service

CONNECTICUT

RHODE ISLAND

MASSACHUSETTS

RHODE ISLAND

RHODE ISLAND

MASSACHUSETTS

NARRAGANSETT BAY

42o00' 

71o

45' 

41o

15' 

41o

30' 

71o

30' 

0109000406

01090004

010900040601

EXPLANATION

8-DIGIT U.S. GEOLOGICAL SURVEY HYDROLOGIC 

UNIT CODE BOUNDARY AND NUMBER

10-DIGIT WATERSHED BOUNDARY DATASET

BOUNDARY—Only Pawtuxet number shown

12-DIGIT WATERSHED BOUNDARY DATASET

 BOUNDARY—Only study-area subbasins 

are numbered. See table 5

Figure 6. The 8-, 10-, and 12-digit Watershed Boundary Dataset delineations for the Pawtuxet and Quinebaug River Basins, 

central and western Rhode Island.
14 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

1Scituate Reservoir Complex subbasin includes the

Watershed Boundary Dataset 12-digit numbers 010900040604, 010900040605, and 010900040606. 1Scituate Reservoir Complex subbasin includes theWatershed Boundary Dataset 12-digit number 010900040604, 010900040605, and 010900040606. 2North Branch Pawtuxet subbasin includes the Watershed Boundary Dataset 12-digit number 010900040607. 3South Branch Pawtuxet subbasin includes the Watershed Boundary Dataset 12-digit numbers 010900040601, 010900040602, and 010900040603. 4Northeastern Pawtuxet subbasin includes the Watershed Boundary Dataset 12-digit numbers 010900040608 and 010900040609. 5Areas of the Quinebaug River Basin 10-digit and 12-digit datasets extend into Massachusetts and Connecticut (fig. 9), but were not used in this assessment. 

Table 5. Defined subbasins in the Pawtuxet and Quinebaug River Basin study areas in Rhode Island compared to the 10-digit and 12-digit Natural Resources Conservation Service Watershed Boundary Dataset (2003) for Rhode Island[Total land area for the Natural Resources Conservation Service Watershed Boundary Dataset for the Quinebaug River Basin 8-digit Hydrologic Unit Code (01100001) in Rhode Island is 60.97 mi

2; 

outside of the study area, the areas of the Quinebaug River Basin in Connecticut and Massachusetts are about 433 and 249 mi

2, respectively. Numbers may not add to totals because of rounding; mi

2, square mile]

Pawtuxet River Basin study area in

Rhode Island Watershed Boundary Dataset for Pawtuxet River Basin

Subbasin

Drainage

area

(mi2

)

10-digit 12-digit

 Name Number Drainage area (mi2

) Name Number Drainage area (mi

2

)

Scituate Reservoir Complex1 94.11 Pawtuxet River 0109000406 231.6

Regulating and Moswansicut Reservoirs 010900040604 122.10

North Branch Pawtuxet2 14.09 Ponaganset and Barden Reservoirs 010900040605 132.99South Branch Pawtuxet3 72.68 Scituate and Westconnaug Reservoirs 010900040606 139.01Northeastern Pawtuxet4 50.71 North Branch Pawtuxet River 010900040607 214.09

Big River 010900040601 328.41Flat River 010900040602 327.75South Branch Pawtuxet River 010900040603 316.52Pocasset River 010900040608 420.61Pawtuxet River mainstem 010900040609 430.11

Total Pawtuxet River Basin 

study area 231.6 Total Pawtuxet River Basin 231.6

Total Pawtuxet River Basin 231.6

Quinebaug River Basin study area in

Rhode Island Watershed Boundary Dataset for Quinebaug River Basin in Rhode Island

Basin

Drainage

area

(mi

2

)

10-digit 12-digit

 Name Number Drainage area (mi2

) Name Number Drainage area (mi2

)

Quinebaug5 60.97 Fivemile River 0110000103 19.26 Upper Fivemile River 011000010301 11.67

Lower Fivemile River 011000010302 7.588

Moosup River 0110000105 40.31 Upper Moosup River 011000010501 33.81

Quaduck Brook 011000010502 6.350Lower Moosup River 011000010503 .155

Pachaug River 0110000106 1.435 Upper Pachaug River 011000010601 1.435

Total Quinebaug River Basin study area in Rhode Island 60.97

Total Quinebaug River Basin inRhode Island 61.01

Total Quinebaug River Basin inRhode Island 61.01
The Pawtuxet River Basin 15

Surficial Geology from Rhode Island

Geographic Information System,

1/4 Acre Resolution, 1989,

Rhode Island State Plane Projection,

1983 North American datum,

1:24,000 scale

71o45'

71o

37'30"

41o45'

41o52'30"

EXPLANATION

0

0

1 2 3 4 5 MILES

1 2 3 4 5 KILOMETERS

TILL AND BEDROCK

SAND AND GRAVEL DEPOSITS

SCITUATE RESERVOIR COMPLEX SUBBASIN BOUNDARY

U.S. GEOLOGICAL SURVEY PARTIAL-RECORD

STREAM-GAGING STATIONS

Ponaganset Reservoir

Moswansicut 

Reservoir

Scituate 

Reservoir

Westconnaug 

Reservoir

Barden

Reservoir

Regulating

Reservoir

Base from USGS Digital Data

State Plane Feet Zone 5176

1:24,000 scale

Figure 7. Scituate Reservoir Complex subbasin with selected partial-record stream-gaging stations and surficial 

deposits, Pawtuxet River Basin, central Rhode Island.
16 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

NA

R

RAGANSETT

BAY

0 5 KILOMETERS

0 5 MILES

41o30’

Base from U.S. Geological Survey and Rhode Island Geographic Information System digital data (1999), 1:24,000,

Lambert conformal conic projection. 1983 North American datum

41o45’

42o00’

71o45’ 71o30’ 71o15’

PAWTUXET RIVER BASIN

QUINEBAUG

RIVER

BASIN

01115630

01116000

01115500

01111500

01116500

01115098

01115187

01115770

01115110

01117370

01117800

01126224

01126200

01115900

01115670

01115700

SCITUATE RESERVOIR 

COMPLEX

NORTHEASTERN 

PAWTUXET 

NORTH BRANCH

PAWTUXET

SOUTH BRANCH

PAWTUXET

17

18

20 19 10

4

3

2

8 9

7

6

5

MASSACHUSETTS

CONNECTICUT

RHODE ISLAND

D

A

B

C

EXPLANATION

01115187

A

2

1

11

12

13

14

16

15

MAJOR BASIN BOUNDARY

DETAILED SUBBASIN BOUNDARIES WITHIN

THE PAWTUXET BASIN

STREAM-GAGING STATION AND NUMBER

RHODE ISLAND POLLUTION DISCHARGE 

ELIMINATION SYSTEM (RIPDES) SITE AND 

REFERENCE NUMBER—See table 16

WASTEWATER-TREATMENT PLANT—See table 17

Figure 8. Stream-gaging stations, Rhode Island Pollutant Discharge Elimination System sites, and wastewater-treatment plants 

associated with the Pawtuxet and Quinebaug River Basins, central and western Rhode Island.
The Pawtuxet River Basin 17

The South Branch Pawtuxet subbasin (72.68 mi2

 drainage 

area) is in the southern section of the Pawtuxet River Basin. The 

towns in the subbasin are Coventry, East Greenwich, Exeter, 

Foster, Scituate, Warwick, West Greenwich, and West Warwick (fig. 4). In the southern part of the subbasin, the Nooseneck River flows into the Big River from the west, and the Carr 

River flows into the Big River from the east. The Big River 

flows north to the Flat River Reservoir in the western part of the 

subbasin. The reservoir is used for recreation, and the flow out 

of the reservoir is regulated by three flashboards, although no 

discharge data are collected. The outflow eastward from the reservoir is called the South Branch Pawtuxet River. The Mishnock River flows north from Lake Mishnock to its confluence 

with the South Branch Pawtuxet River. The main stem of the 

Pawtuxet River forms at the confluence of the South Branch 

Pawtuxet River and the North Branch Pawtuxet River.

The Mishnock aquifer is entirely within the South Branch 

Pawtuxet subbasin. The major public-supply withdrawals in the 

South Branch Pawtuxet subbasin are by the Kent County Water 

Authority, which withdraws water from the Mishnock aquifer 

(fig. 5). Self-suppliers withdraw water from the sand and gravel 

deposits, till deposits, and bedrock. Because the three major 

river and ground-water systems are hydrologically linked 

through the sand and gravel deposits in the subbasin, they were 

grouped together for estimations of water withdrawal, use, and 

availability in the subbasin. The area of the surficial deposits in 

the subbasin is 41 percent sand and gravel (fig. 5). The only 

continuous stream-gaging station in the subbasin is the South 

Branch Pawtuxet River at Washington (01116000) with a drainage area of 62.8 mi2 (fig. 8). About 40 percent of the drainage 

area to this station is sand and gravel deposits. The USGS has 

been collecting surface-water data at this station for more than 

63 years. Two discontinued stream-gaging stations, Nooseneck 

River at Nooseneck (01115630) and Carr River near Nooseneck 

(01115770) (fig. 8), have 17 and 16 years of record, respectively. The drainage areas for the Nooseneck River station and 

the Carr River station are 8.28 mi2 and 7.33 mi2, respectively. 

The percentages of sand and gravel deposits for the areas 

upstream of the stations are about 35 percent for the Nooseneck 

River station and 63 percent for the Carr River station. 

The Northeastern Pawtuxet subbasin (50.71 mi2 drainage 

area) is in the northeastern section of the Pawtuxet River Basin. 

The subbasin includes the towns of Cranston, Johnston, Providence, Warwick, and West Warwick (fig. 4). The subbasin 

includes the Pocasset River and the main stem of the Pawtuxet 

River. The Pocasset River flows southeast into the main stem of 

the Pawtuxet River in Cranston. The Pawtuxet River confluence 

with Narragansett Bay is in the easternmost part of the basin in 

the village of Pawtuxet. The surficial deposits in the subbasin 

are about 47 percent sand and gravel deposits. The USGS has 

been collecting surface-water data for more than 64 years at the 

one continuous stream-gaging station is in the subbasin (fig. 8), 

the Pawtuxet River at Cranston (01116500). Twenty-eight percent of the surficial deposits upstream of the station are sand 

and gravel. 

The Providence-Warwick aquifer (fig. 5) is a defined 

ground-water source that extends along Narragansett Bay and 

crosses the Moshassuck, Woonasquatucket, Pawtuxet, and Narragansett Bay Basins in a north-south direction. Because data on 

this particular aquifer are limited, ground-water drainage 

divides were not used in the calculations of water use and availability. In addition, losses from lateral ground-water movement 

out of the basin were considered negligible for this study. 

Minor Civil Divisions

The U.S. Census Bureau classifies towns and cities into 

minor civil divisions (MCDs). The 13 MCDs in the study area 

include Coventry, Cranston, East Greenwich, Exeter, Foster, 

Glocester, Johnston, Providence, Scituate, Smithfield, Warwick, West Greenwich, and West Warwick. Polygons within 

the towns were assigned population densities by using Census 

Bureau Topologically Integrated Geographic Encoding and 

Referencing (TIGER) system data available through RIGIS 

coverages. These 1990 population coverages were merged with 

the USGS basin and subbasin coverages to determine the population in the Pawtuxet River Basin and its subbasins (table 2). 

Also, town land area apportioned by basin and subbasin was 

determined by overlaying town boundaries and basin-boundary 

coverages (table 3). The population for a city or town was calculated by averaging the 1995, 1996, 1997, 1998, and 1999 populations estimated by the Rhode Island Economic Development 

Corporation (2001). The percentage of the total 1990 population for each town in each subbasins was applied to the estimated 1995–99 population for that town.

Public water suppliers are defined by the U.S. Environmental Protection Agency (USEPA) as suppliers serving more 

than 25 people or having 15 service connections year-round 

(U. S. Government Printing Office, 1996). Public suppliers 

were categorized into major public suppliers that have a system 

of distribution and minor public suppliers that have closed systems. The 1990 population on self-supply for the part of a town 

within a given subbasin was divided by the 1990 population for 

that part of the town. This procedure was repeated for the 1990 

populations on public-wastewater collection. The resulting percentages of the 1990 populations on self-supply and wastewater 

collection in the subbasins for each town were applied to the 

1995–99 populations to provide estimates of the 1995–99 populations on self-supply and public disposal (table 2). The 1995–

99 populations on public supply and self-disposal were determined by subtracting the 1995–99 populations on self-supply 

and public disposal from the total 1995–99 populations in the 

subbasins for each town (table 2).

The town of Coventry is in central Rhode Island (fig. 1). 

The total land area is 62.45 mi2, of which 41.24 mi2 is in the 

Pawtuxet River Basin. The total town population in the basin 

for the study period (1995–99) was 30,815 out of a total town 

population of 32,523 (table 6). One major public water supplier, 

the Kent County Water Authority, supplies water to the eastern
18 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99 Table 6. Summary of total town land area, land area in the Pawtuxet and Quinebaug River Basins, total 1990 town populations and estimated 1995–99 populations, and land-use area by category in the Pawtuxet and Quinebaug River Basins, central and western Rhode Island.

[All towns are in Rhode Island unless other

wise noted. Total 1990 populations in Rhode Island were obtained from Rhode Island Geographic Information System (1991). Populations for 1995–99 were estimated 

from Rhode Island Economic Development Corporation (2001). Land-use areas in Rhode Island were estimated by using the coverage from the Rhode Island Geographic Information System (1995a).mi2, square mile; --, not applicable]

Total Land area in Land area in Total populations Estimated 1995–99 Estimated 1995–99 Total land-use area by category (mi2

)

land the Pawtuxet the Quinebaug population in population in Towns Estimated area River Basin River Basin the Pawtuxet the Quinebaug 1990 Commercial Industrial

Agricultural 1995–99 (mi2

) (mi2

) (mi2

) River Basin River Basin

Burrillville 56.96 -- 8.595 16,229 15,910 -- 514 0.209 0.183 2.182Coventry 62.45 41.24 20.30 31,081 32,523 30,815 1,569 .627 .355 2.392Cranston 28.90 28.18 -- 76,077 74,890 68,784 -- 1.177 1.174 2.609East Green

wich 16.25 .140 -- 11,807 12,120 50 -- .349 .195 .924

Exeter 58.39 3.247 1.432 5,472 5,932 398 81 .140 .042 4.451Foster 51.94 31.85 20.09 4,316 4,410 2,727 1,684 .247 .042 2.779Glocester 56.83 16.39 9.703 9,227 9,280 2,815 647 .279 .055 3.039Johnston 24.33 16.54 -- 26,606 26,433 13,985 -- .779 .398 1.412Providence 18.78 2.952 -- 160,262 151,151 23,957 -- 2.180 1.701 .008Scituate 54.81 54.79 -- 9,793 10,012 10,006 -- .188 .028 2.314Smithfield 27.61 .032 -- 19,163 18,906 90 -- .699 .388 1.459Warwick 35.02 7.183 -- 85,457 84,038 17,081 -- 2.598 1.138 1.217West Greenwich 51.22 23.10 .853 3,501 3,956 2,330 46 .227 .064 1.865West Warwick 8.091 5.943 -- 29,278 29,034 21,925 -- .557 .464 .108
The Pawtuxet River Basin 19

section of Coventry. Two minor public water suppliers serve 

small populations in the eastern part of the town in the Pawtuxet 

River Basin. The wastewater-collection area for the eastern section of Coventry is maintained by the West Warwick Regional 

Wastewater-Treatment Facility (WWTF). 

The city of Cranston is in central Rhode Island (fig. 1). The 

total land area is 28.90 mi2, of which 28.18 mi2

 is in the Pawtuxet River Basin. The total city population in the basin for the 

study period was 68,784 out of a total town population of 

74,890 (table 6). The city purchases water from ProvWater. The 

interconnections with ProvWater that serve the part of the city 

west of Interstate 295 were maintained by the Cranston Water 

District until 1997. ProvWater also supplies Cranston’s retail 

sales of water in the area east of Interstate 295; this area is part 

of ProvWater’s retail-service area. The US Filter Cranston 

Water Pollution Control Facility and the West Warwick 

Regional WWTF collect and process wastewater for certain 

areas in Cranston.

The town of East Greenwich is in central Rhode Island 

(fig. 1). The total land area is 16.25 mi2

, of which 0.140 mi2 is 

in the Pawtuxet River Basin. The total town population in the 

basin for the study period was 50 out of a total town population 

of 12,120 (table 6). The Kent County Water Authority supplies 

water to all of East Greenwich, and the East Greenwich WWTF 

collects wastewater for the community. 

The town of Exeter is in south central Rhode Island 

(fig. 1). The total land area is 58.39 mi2

, of which 3.247 mi2 is 

in the Pawtuxet River Basin. The total town population in the 

basin for the study period was 398 out of a total town population 

of 5,932 (table 6). No public water suppliers are in the part of 

Exeter in the basin. Outside the basin, the Ladd School operated 

as a minor public water supplier and small facility that treated 

their wastewater for 5 months (from January through May of 

1995). The facility is currently (2004) owned by the Rhode 

Island Economic Development Corporation (RIEDC) and is 

undeveloped. 

The town of Foster is in western Rhode Island (fig. 1). The 

total land area is 51.94 mi2, of which 31.85 mi2 is in the Pawtuxet River Basin. The total town population in the basin for the 

study period was 2,727 out of a total town population of 4,410 

(table 6). Foster has no major public water suppliers; likewise, 

the town has no local wastewater collection. Three minor public 

water suppliers, however, serve small populations in the town. 

The town of Glocester is in western Rhode Island (fig. 1). 

The total land area is 56.83 mi2, of which 16.39 mi2 is in the 

Pawtuxet River Basin. The total town population in the basin 

for the study period was 2,815 out of a total town population of 

9,280 (table 6). Glocester has no public water supply in the 

basin; likewise, the town has no local wastewater collection. 

The town of Johnston is in central Rhode Island (fig. 1). 

The total land area is 24.33 mi2, of which 16.54 mi2 is in the 

Pawtuxet River Basin. The total town population in the basin 

for the study period was 13,985 out of a total town population 

of 26,433 (table 6). During the study period, the Cranston Water 

District served the area of the town area west of Interstate 295 

until 1997. From 1997 to the present (2004), the area has been 

served by the Johnston Water District. ProvWater serves the 

area in Johnston east of Interstate 295; this area is part of ProvWater’s retail service area. No minor public water suppliers are 

in the part of Johnston that is in the basin. Johnston has no local 

wastewater collection; however, the town wastewater is collected and processed by a regional facility, the Narragansett Bay 

Commission facility at Fields Point in Providence. This WWTF 

is along Narragansett Bay and discharges to the bay.

The city of Providence is in central Rhode Island (fig. 1). 

The total land area is 18.78 mi2

, of which 2.952 mi2 is in the 

Pawtuxet River Basin. The total city population in the basin for 

the study period was 23,957 out of a total city of 151,151 

(table 6). ProvWater serves the city. No minor public water suppliers are in the part of Providence that is in the basin. City 

wastewater is collected and processed by the NBC facility at 

Fields Point in Providence.

The town of Scituate is in central Rhode Island (fig. 1). 

The total land area is 54.81 mi2, of which 54.79 mi2

 is in the 

Pawtuxet River Basin. The total town population in the basin 

for the study period was 10,006 out of a total town population 

of 10,012 (table 6). The Kent County Water Authority serves 

the southeastern corner of the town, and the Johnston Water 

District serves the northeastern part of the town. Three minor 

public water suppliers serve small populations in the town. The 

West Warwick Regional WWTF collects and processes wastewater for the southeast corner of Scituate.

The town of Smithfield is in north central Rhode Island 

(fig. 1). The total land area is 27.61 mi2

, of which 0.032 mi2 is 

in the Pawtuxet River Basin. The total town population in the 

basin for the study period was 90 out of a total town population 

of 18,906 (table 6). The part of Smithfield that is in the basin has 

no public water supply or wastewater collection. 

The city of Warwick is in central Rhode Island (fig. 1). The 

total land area is 35.02 mi2, of which 7.183 mi2 is in the Pawtuxet River Basin. The total town population in the basin for the 

study period was 17,081 out of a total town population of 

84,038 (table 6). The major public water supplies for the city are 

operated and maintained by the Warwick Water Department 

and the Kent County Water Authority. Warwick purchases 

water from ProvWater. The Kent County Water Authority, in 

addition to obtaining water from its own withdrawal wells, purchases water wholesale from ProvWater and the Warwick 

Water Department. No minor public water suppliers are in the 

part of Warwick that is in the Pawtuxet River Basin. The Warwick WWTF and the West Warwick Regional WWTF collect 

and process wastewater for the city.

The town of West Greenwich is in central Rhode Island 

(fig. 1). The total land area is 51.22 mi2

, of which 23.10 mi2 is 

in the Pawtuxet River Basin. The total town population in the 

basin for the study period was 2,330 out of a total town population of 3,956 (table 6). The Kent County Water Authority serves 

the part of West Greenwich that is in the basin. One minor water 

supplier serves a small population in the basin. A small area of 

West Greenwich in the basin is served by the West Warwick 

Regional WWTF. 
20 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

The city of West Warwick is in central Rhode Island 

(fig. 1). The total land area is 8.091 mi2, of which 5.943 mi2 is 

in the Pawtuxet River Basin. The total town population in the 

basin for the study period was 21,925 out of a total town population of 29,034 (table 6). The Kent County Water Authority 

serves West Warwick. City wastewater is collected and processed by the West Warwick Regional WWTF. 

The Quinebaug River Basin

The Quinebaug River Basin is in western Rhode Island, 

eastern Connecticut, and south central Massachusetts (fig. 9). 

The total land area in the basin is about 743 mi2

 (Thomas and 

others, 1966), which includes about 60.97 mi2

 in Rhode Island, 

about 433 mi2 in Connecticut, and about 249 mi2

 in Massachusetts (Simcox, 1992). Four major tributaries enter the 

Quinebaug River in Connecticut, including the French River 

from the north, the Fivemile River from the northeast, the 

Moosup River from the east, and the Pachaug River from the 

southeast (fig. 9). Only the part of the basin in Rhode Island, 

however, was included in this analysis. 

Six Rhode Island towns are partially within the basin. In 

1990, the basin population was about 4,483, and the estimated 

population during the study period was 4,541 (table 2). The 

Quinebaug River Basin is mostly hilly, with higher altitudes in 

the northwest. No defined principal aquifers are in the study 

area; however, it does include areas of stratified sand and gravel 

deposits (fig. 5). On the basis of the surface-water-drainage 

boundaries, about 27.1 percent of the area of the surficial 

deposits in the Quinebaug River Basin is stratified sand and 

gravel deposits. 

The USGS subbasin boundaries delineated for this study 

area differ from the cataloging units defined by the WBD 

(fig. 6). Naming conventions also differ between the Quinebaug 

River Basin study and the 10-digit and 12-digit cataloging units. 

The study area was defined by the USGS 8-digit HUC because 

use of the 10-digit cataloging units resulted in withdrawals and 

water use less than 0.001 Mgal/d when estimated by town, and 

because there are no defined ground-water aquifers in the basin. 

Comparisons of land-area and naming conventions between the 

Quinebaug River Basin and the WBD cataloging units are presented in table 5. 

The town of Burrillville is in northwestern Rhode Island 

(fig. 1). The total land area is 56.96 mi2, of which 8.595 mi2 is 

in the Quinebaug River Basin. The total town population in the 

basin for the study period was 514 out of a total town population 

of 15,910. For the town of Coventry, the land area in the basin 

is 20.30 mi2

, and the estimated town population in the basin was 

1,569 (table 6). One minor public water supplier serves a small 

population in the part of the town in the basin. The land area in 

Exeter in the basin is 1.432 mi2

, and the estimated town population in the basin was 81. The land area in Foster in the basin 

is 20.09 mi2

, and the estimated town population in the basin was 

1,684. The land area in Glocester in the basin is 9.703 mi2

, and 

the estimated town population in the basin was 647. The land 

area in West Greenwich in the basin is 0.853 mi2

, and the estimated town population in the basin was 46 (table 6). The 

Quinebaug River Basin had no local or regional wastewatercollection service areas during the study period.

Estimated Water Use

Water-use data for the study period for the Pawtuxet and 

Quinebaug River Basins were organized by using NEWUDS. 

Components of water use include water withdrawals, publicsupply distributions, nonaccount use, water use by category, 

consumptive water use, wastewater-system collections, and 

return flow (fig. 3). Withdrawal data were categorized as either 

self- or public supply from surface and ground water. Conveyance losses are an example of nonaccount water use (which is 

unmetered) in public-supply systems, and include leaks, system 

flushing, and fire-hydrant uses. The nonaccount water use for a 

public-supply system is calculated as the difference between the 

total distribution and the distributions received for all of the 

water-use categories in the system. Water-use categories in this 

report are domestic, commercial, industrial, and agricultural for 

public-supply and self-supply users. The public supply withdrawals were from surface and ground water, whereas minor 

public-supply and self-supply domestic, industrial, and commercial withdrawals were only from ground water. Consumptive water use is water removed from the environment through 

uses by humans, livestock, production, or evapotranspiration. 

Wastewater from a local or a regional public wastewater system 

is returned to a surface-water body. Return flow to ground water 

or surface water includes wastewater disposed from site-specific discharges, permitted discharges, and aggregate discharges. Water withdrawals, water use, consumptive use, and 

return flow were calculated for each subbasin by town for the 

calendar years during the study period. Because the Quinebaug 

River Basin has no major public water suppliers, wastewater 

collection, and interbasin transfers, the sections of the report on 

these topics pertain only to the Pawtuxet River Basin. 

New England Water-Use Data System

The NEWUDS database was used as a tool to track the 

water withdrawn in the Pawtuxet and Quinebaug River Basins. 

The database was queried to obtain the average water use for the 

study period, and the results are presented in the tables of this 

report. The data entered into NEWUDS consist of site-specific 

and aggregate water withdrawals, uses, and discharges in the 

two basins. When available, monthly, quarterly, and (or) yearly 

metered (or reported) data were entered as reported from the 

original source, and were converted to common units (Mgal/d) 

for comparison into NEWUDS. Unmetered water withdrawals, 

uses, and discharges were calculated by methods used to estimate water use by category. For quality-assurance purposes, 

NEWUDS allows the data compiler to indicate the original data
Estimated Water Use 21

BURRILLVILLE

GLOCESTER

FOSTER SCITUATE

JOHNSTON

NORTH

PROVIDENCE

PROVIDENCE

CRANSTON

WEST

WARWICK

COVENTRY

WEST GREENWICH EAST 

GREENWICH

EXETER

NORTH

KINGSTOWN

RICHMOND

NORTH

SMITHFIELD

SMITHFIELD

LINCOLNWARWICK

SOUTH

KINGSTOWN NARRAGANSETT

CHARLESTOWN

HOPKINTON

WESTERLY

WOONSOCKET

CUMBERLAND

MASSACHUSETTS

MASSACHUSETTS

CONNECTICUT

CONNECTICUT

RHODE ISLAND

RHODE ISLAND

Quinebaug

River

Lower Fivemile

French River

Upper Moosup

FivemileRiv e r

Qui nebaug

R i ver

Quinebaug

River

Moos up River

Upper Fivemile

Q uaduck Brook

Upper Pachaug

Pachaug

River

MONTVILLE LEDYARD

WATERFORD

BOZRAH NORWICH

FRANKLIN

SPRAGUE

LISBON

PRESTON

WINDHAM

HAMPTON

CHAPLIN

SCOTLAND

UNION

WOODSTOCK

ASHFORD

THOMPSON

PUTNAM

POMFRET

EASTFORD

KILLINGLY

BROOKLYN

CANTERBURY

PLAINFIELD

STERLING

GRISWOLD

NORTH

STONINGTON

VOLUNTOWN

MANSFIELD WILLINGTON

STAFFORD

LEBANON

STONINGTON

SALEM

Q u ni ebaug River

QUINEBAUG RIVER BASIN

HOLLAND

BRIMFIELD CHARLTON

SOUTHBRIDGE

DUDLEY

WEBSTER

OXFORD

AUBURN

MENDON

MEDWAY

BROOK- HOLLISTON

FIELD

EAST

WARREN

BROOKFIELD

SPENCER LEICESTER

WALES

STURBRIDGE

GRAFTON

UPTON

UXBRIDGE

NORTHBRIDGE

SUTTON

DOUGLAS

BELLINGHAM

MILLBURY

MILFORD

FRANKLIN

HOPKINTON

HOPEDALE

MILLVILLE

BLACKSTONE

SHREWSBURY WESTBOROUGH

SOUTHBOROUGH

WORCESTER

PAXTON

NORTH

BROOKFIELD WEST

BROOKFIELD

WARE

PALMER

WRENTHAM

ASHLAND

SHERBORN

FRAMINGHAM

71o45' 71o 72 30' o

00' 72o

15'

42o

15'

42o

00'

42o

45'

42o

30'

Map composited from U.S. Geological Survey, MassGIS, Rhode Island Geographic Information System, 

and Connecticut Map and Geographic Information System sources

1983 North American datum

CONNECTICUT RHODE

ISLAND

NEW YORK VERMONT

MASSACHUSETTS

NEW HAMPSHIRE Atlantic Ocean

0 5 10 MILES

0 10 KILOMETERS

Figure 9. The Quinebaug River Basin in western Rhode Island, northeastern Connecticut, and south-central Massachusetts.
22 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

source, rate units, and the method of reporting the water-use 

rate. Documentation describing database development and how 

to use the database are presented in Tessler (2002) and Horn 

(2003), respectively. 

Public Water Supply and Interbasin Transfers 

Five major public suppliers served the domestic, commercial, industrial, and agricultural sectors in the Pawtuxet River 

Basin during the study period (table 7, fig. 10): Cranston Water 

District, Johnston Water District, Kent County Water Authority, Providence Water Supply Board, and Warwick Water 

Department. Ten minor water suppliers, such as nursing homes, 

condominium associations, and mobile home parks, served 

small public populations; nine minor suppliers were in the Pawtuxet River Basin and one was in the Quinebaug River Basin 

(table 8). The total public-supply withdrawals by subbasin and 

town are summarized in table 9. 

Potable interbasin transfers are water that is conveyed 

from public water suppliers across hydrologic divides between 

basins and subbasins. The water is an import, or a gain to the 

Pawtuxet River Basin, if the water is withdrawn in another 

basin or subbasin and used in the Pawtuxet River Basin. 

The water is an export, or a loss to the basin, if the water is 

withdrawn in the basin but used elsewhere in another basin 

or subbasin.

Table 7. Withdrawals by major public water-supply districts in and outside the subbasins of the Pawtuxet River Basin, 

central Rhode Island, 1995–99.

[The Cranston and Johnston Water Districts and the Warwick Water Department do not withdraw water; they only purchase water. Reference number: Identifier

used in figure 5. Aquifer type: SG, sand and gravel. HAP, Hunt-Annaquatucket-Pettaquamscutt; Mgal/d, million gallons per day; --, not applicable]

Aquifer Water Location of Well field and well Reference withdrawals Major public water-supply district surface-water description number 1995–99 Type Name intake (Mgal/d) (Mgal/d)

Pawtuxet River Basin

Scituate Reservoir Complex Subbasin

Providence Water Supply Board A Scituate Reservoir -- -- -- 70.85

Subbasin total 70.85

North Branch Pawtuxet Subbasin

-- -- -- -- -- -- --

South Branch Pawtuxet Subbasin

Kent County Water Authority B -- Mishnock Well 1 SG Mishnock 0.338

C -- 1Mishnock Well 2 SG Mishnock .363

D -- 2Mishnock Well 3 SG Mishnock --

E -- Spring Lake Well SG Mishnock .305

Subbasin total 1.006

Northeastern Pawtuxet Subbasin

-- -- -- -- -- -- --

Basin total 71.86

Withdrawals outside the Pawtuxet River Basin

Kent County Water Authority F -- East Greenwich Well SG HAP 0.586

1Mishnock well 2 was discontinued after October 1999.

2Mishnock well 3 was drilled near the site of discontinued Mishnock well 2. Withdrawals started in March 2000 and continue to the present (2004).
Estimated Water Use 23

MASSACHUSETTS

CONNECTICUT

RHODE ISLAND

WOONSOCKET

NORTH SMITHFIELD

BURRILLVILLE

GLOCESTER

SMITHFIELD

JOHNSTON

SCITUATE

CRANSTON

BARRINGTON WARREN

BRISTOL

COVENTRY

WEST GREENWICH

EAST

GREENWICH

WEST WARWICK

WARWICK

EXETER

NORTH

KINGSTOWN

FOSTER

CUMBERLAND

LINCOLN

PAWTUCKET NORTH PROVIDENCE

EAST PROVIDENCE

PROVIDENCE

WARWICK

SCITUATE RESERVOIR 

COMPLEX

NORTHEASTERN 

PAWTUXET 

NORTH BRANCH

PAWTUXET

SOUTH BRANCH

PAWTUXET

PAWTUXET RIVER BASIN

QUINEBAUG

RIVER

BASIN

QUINEBAUG

RIVER

BASIN

EXPLANATION

Other service areas

Providence Water Supply Board 

Johnston Water District

Cranston Water District

Warwick Water Department

Kent County Water Authority

East Providence Water Department

Bristol County Water Authority

Smithfield Water Supply Board

Greenville Water District

East Smithfield Water District

MAJOR PUBLIC WATER-SUPPLY DISTRICTS—Districts in Pawtuxet study area are in bold type. See figures 11-14 for schematic diagrams of water distribution

Lincoln Water Commission

MAJOR BASIN BOUNDARY

STUDY SUBBASIN BOUNDARY

NARRAGANSETT BAY 

0 5 KILOMETERS

0 5 MILES

41o45'

42o

00'

71o

45' 71o30' 71o15'

Base from U.S. Geological Survey and Rhode Island Geographic Information System digital data (1995b), 1:24,000,

Lambert conformal conic projection. 1983 North American datum

Figure 10. Public water-supply districts associated with the Pawtuxet River Basin and in the northern Narragansett Bay area, 

Rhode Island.
24 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

Table 8. Minor public water suppliers by subbasin in the Pawtuxet River Basin, central Rhode Island, and in the Quinebaug River Basin, 

western Rhode Island, 1995–99.

[Shaded areas are basin totals. Minor public water supplier: Coefficient used for minor supplier population is 67 gal/d/person. Reference number: Identifier

used in figure 5. Aquifer type: BD, bedrock; SG, sand and gravel. gal/d/person, gallons per day per person; Mgal/d, million gallons per day; --, not applicable]

Minor public water supplier Reference

number

Town Aquifer type 

Estimated 1995–99

Water

withdrawals Population and use

(Mgal/d)

Pawtuxet River Basin

Scituate Reservoir Complex Subbasin

Abbey Lane Community Association

Nancy Ann Nursing Home, Inc.

Hemlock Village

Oak Crest Manor, Inc.

Scituate Housing for the Elderly/Rockland Oaks

Scituate Commons

Subbasin total

1

2

3

4

5

6

Foster

Foster

Foster

Scituate

Scituate

Scituate

BD

BD

BD

BD

BD

BD

46

20

34

46

26

35

0.003

.001

.002

.003

.002

.002

207 0.013

North Branch Pawtuxet Subbasin

-- -- -- -- -- --

South Branch Pawtuxet Subbasin

Blueberry Heights Mobile Park

Alpine Nursing Home

Woodland Homeowners Association

Subbasin total

7

8

9

West Greenwich

Coventry

Coventry

BD

BD

SG

50

29

120

.003

.002

.008

199 0.013

Northeastern Pawtuxet Subbasin

--

Basin total

-- -- -- -- --

406 0.026

Quinebaug River Basin

Woodpecker Hill Nursing Home 10 Coventry BD 40 0.003

Basin total 40 0.003
Estimated Water Use 25

Table 9. Ground-water and surface-water withdrawals by town and subbasin in the Pawtuxet River Basin, central Rhode Island, 

and in the Quinebaug River Basin, western Rhode Island, 1995–99.

[Shaded areas are basin totals. Withdrawals are from ground-water wells and surface-water reservoirs. For agricultural use, irrigation water withdrawals are

assumed to be 81 percent from surface water (ponds and rivers) and 13 percent from ground water (wells). Livestock water withdrawals are assumed to be 9 

percent from surface water and 82 percent from ground water. The remaining 6 percent for irrigation and 9 percent for livestock are assumed to be from public 

supply. All towns are in Rhode Island unless otherwise noted. Mgal/d, million gallons per day; <0.001, value not included in totals; --, not applicable]

Towns

Public-supply

withdrawals

(Mgal/d)

Self-supply withdrawals (Mgal/d) Total

Domestic Commercial (Mgal/d) Industrial Agricultural

Pawtuxet River Basin

Scituate Reservoir Complex Subbasin

Cranston -- 0.003 -- -- 0.002 0.005

Foster 0.006 .171 0.001 0.002 .002 .182

Glocester -- .200 .007 -- .003 .210

Johnston -- .038 -- -- .001 .039

Scituate 70.86 .538 .008 .012 .007 71.43

Smithfield -- .006 -- -- <.001 .006

Subbasin total 70.87 0.956 0.016 0.014 0.015 71.87

North Branch Pawtuxet Subbasin

Coventry -- 0.035 -- 0.009 0.003 0.047

Cranston -- .023 <0.001 -- .005 .028

Scituate -- .058 -- -- .003 .061

West Warwick -- .002 -- -- -- .002

Subbasin total -- 0.118 <0.001 0.009 0.011 0.138

South Branch Pawtuxet Subbasin

Coventry 1.016 0.430 0.004 0.017 0.022 1.489

East Greenwich -- .001 -- -- -- .001

Exeter -- .028 .001 -- .002 .031

Foster -- .015 -- -- .003 .018

Scituate -- .020 -- -- .001 .021

Warwick -- -- -- -- -- --

West Greenwich .003 .113 .001 .065 <.001 .182

West Warwick -- .005 -- -- -- .005

Subbasin total 1.019 0.612 0.006 0.082 0.028 1.747

Northeastern Pawtuxet Subbasin

Cranston -- 0.070 0.015 0.011 0.019 0.115

Johnston -- .149 .027 .004 .001 .181

Providence -- -- -- -- -- --

Warwick -- <.001 -- -- -- <.001

West Warwick -- .010 -- -- -- .010

Subbasin total -- 0.229 0.042 0.015 0.020 0.306

Basin total 71.89 1.915 0.064 0.120 0.074 74.06

Quinebaug River Basin

Burrillville -- 0.036 -- -- <0.001 0.036

Coventry 0.003 .109 0.002 0.004 .007 .125

Exeter -- .006 -- -- -- .006

Foster -- .120 <.001 -- .024 .144

Glocester -- .045 .003 <.001 .001 .049

West Greenwich -- .003 -- -- -- .003

Basin total 0.003 0.319 0.005 0.004 0.032 0.363
26 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

The Cranston Water District purchased water from ProvWater and maintained the six Johnston Water District interconnections until 1997. At this time, Johnston started to maintain 

the interconnections with ProvWater, and the Cranston Water 

District became part of ProvWater’s retail-service area. During 

the transition, records of the historical purchases that the Cranston Water District maintained were destroyed by fire, so they 

were unavailable for this study. 

The Johnston Water District purchases water through six 

interconnections with ProvWater (fig. 11). Monthly data for 

each of the six interconnections were available from January 

1998 through December 1999. The total of the Johnston wholesale purchases for each month was available from ProvWater 

for calendar year 1997, but the monthly data were not available 

for each individual interconnection. Johnston’s monthly wholesale purchases for 1995 and 1996 were not available and were 

estimated on the basis of the 1998 and 1999 data (Peter LePage, 

Providence Water Supply Board, written commun., 2002). 

The Kent County Water Authority system includes Mishnock wells 1, 2, and 3, and Spring Lake well, all of which withdraw from the Mishnock aquifer in the South Branch Pawtuxet 

subbasin (fig. 12). Mishnock well 3 was not in operation during 

the study period. An average of 1.006 Mgal/d was withdrawn 

during the study period from the Mishnock aquifer. The Kent 

County Water Authority withdrawal well in East Greenwich 

withdrew 0.586 Mgal/d from the Hunt-Annaquatucket-Pettaquamscutt aquifer (fig. 5) in the West Narragansett Bay Basin 

(fig. 12). To supplement the system, the Kent County Water 

Authority purchased 6.752 Mgal/d from ProvWater and 1.537 

Mgal/d from the Warwick Water Department (fig. 12). The 

Kent County Water Authority sold 0.221 Mgal/d to the Warwick Water Department to supply Potowomut, a small section 

in Warwick that is east of East Greenwich. 

Water sources for withdrawals and purchases by the Kent 

County Water Authority differed during the study period. To 

determine what percentage of withdrawals and purchases 

occurred during each month of the summer, the well withdrawals for June, July, August, and September were compared to the 

total of the withdrawals and purchases for June, July, August, 

and September, respectively (table 10). Likewise, the percentages of wholesale purchases from each of the interconnections 

for each month were compared to the total water withdrawn and 

purchased June, July, August, and September, respectively 

(table 10). The Kent County Water Authority withdrawals 

ranged from 16 percent in June and July to 18 percent in September of the total water withdrawn and purchased for the system. From the total water withdrawn and purchased for the Kent 

County Water Authority system, withdrawals from the Mishnock aquifer in the Pawtuxet River Basin ranged from 8.6 percent in July to 11 percent in September; withdrawals from the 

East Greenwich well ranged from 6.7 percent in September to 

8.2 percent in August; wholesale water purchases from the Clinton interconnection ranged from 54 percent in July to 61 percent 

in September; wholesale water purchases from the Oaklawn 

interconnection ranged from 1.8 percent in September to 2.8 

percent in July; and wholesale water purchases from the Bald 

Hill interconnection ranged from 19 percent in September to 26 

percent in July. 

In 2000, ProvWater supplied 70.39 percent of the publicsupply surface-water withdrawals and 60.40 percent of all public-supply water withdrawals in Rhode Island. The average rate 

of water withdrawal from the Scituate Reservoir to the J.P. Holton Water Purification Plant for the study period was 70.85 

Mgal/d in the Scituate Reservoir Complex subbasin. ProvWater 

collects data on the rate of water movement within the subbasin; 

35.25 Mgal/d flowed over the spillway and 11.92 Mgal/d 

flowed through the gatehouse during the study period (fig. 13a). 

ProvWater withdrawals conveyed to the purification plant 

accounted for 98.58 percent of the total withdrawals in the Scituate Reservoir Complex subbasin and 95.67 percent of the total 

withdrawals in the Pawtuxet River Basin during the study 

period. Retail distribution was more than 58 percent of the total 

regional distribution from the purification plant to cities inside 

and outside the study area; further analysis and estimation was 

completed to assess the movement of this water within and out 

of the Pawtuxet River Basin (fig. 13b). It was estimated that 

most of the retail sales, about 46 percent, were for domestic 

water users, and about 36 percent of this water was used in the 

Pawtuxet River Basin. 

During the summer when precipitation is limited, water 

use tends to increase. For this reason and because ProvWater 

supplies over 60 percent of the Rhode Island population, average water withdrawal and distribution rates for the system for 

June, July, August, and September were calculated (table 11). 

The regional distribution for the system ranged from 71.81 

Mgal/d in September to 91.52 Mgal/d in July. Retail distribution ranged from 40.45 Mgal/d in September to 49.23 Mgal/d in 

July. Wholesale purchases by other public-supply districts varied from year to year because of water restrictions were different each year and because the sizes of the public-supply districts 

changed. Also, wholesale purchases made by some publicsupply districts from ProvWater varied from one year to the 

next. These districts included the Lincoln Water Commission, 

Kent Count Water Authority, and the Bristol County Water 

Authority. Purchases from ProvWater generally were less in 

September and more in July. The three highest wholesale purchases each accounted for more than 8 percent of the regional 

distribution. 

The Warwick Water Department had no withdrawals during the study period; instead, it purchased 9.649 Mgal/d from 

ProvWater and 0.221 Mgal/d from the Kent County Water 

Authority (fig. 14). The Warwick Water Department also sold 

1.537 Mgal/d to the Kent County Water Authority; of this 

amount, about 0.054 Mgal/d was nonaccount water use. 

Nine minor public suppliers served the Pawtuxet River 

Basin (table 8). Limited data were available on minor publicsupply withdrawals from these users; therefore, water withdrawals and use were estimated by applying the water-use coefficient for domestic users (67 gal/d/person) on public supply 

(Korzendorfer and Horn, 1995). The total of the estimated water 

withdrawn by minor suppliers was 0.026 Mgal/d. There were no
Estimated Water Use 27

PURCHASES, 

WITHDRAWALS, AND 

LOCAL DISTRIBUTION

ESTIMATED RETAIL 

DISTRIBUTION

NONACCOUNT USE

Nonaccount

Use2

0.071

1 Metered data from Johnston interconnections with Providence Water were not 

available and too small to separate in million gallons per day (Mgal/d). The estimated 

transactions for the Green Hill Road, Simmonsville Avenue,Taylor Road, Nardillo Road, 

Capitol, and Rosewood interconnections are about 92.17, 2.93, 0.51, 3.55, 0.62, and 

0.23 percent of the wholesale purchase from Providence Water.

(Peter LePage, Providence Water Supply Board, oral commun., 2002)

2 Johnston nonaccount water use includes firefighting and losses

from system leaks.

TRANSFERS WITHIN

STUDY AREA

EXPLANATION

TRANSFERS TO AND FROM STUDY AREA

PROVIDENCE WATER

SUPPLY BOARD1

Interconnection–Green Hill Road 

0.522

Interconnection–Simmonsville

Avenue 

0.017

Interconnection–Taylor Road 

0.003

Interconnection–Nardillo Road 

0.020

Interconnection–Capitol 

0.003 

Interconnection–Rosewood 

0.001

Johnston Water 

Supply District

Distribution

0.495

Agricultural 0.025

Domestic 0.294 

Commercial 0.064 

Agricultural 0.025

Industrial 0.112 

Figure 11. Johnston Water District interconnections, purchases, distribution, exports, and estimated water uses in the 

Pawtuxet River Basin, central Rhode Island, 1995–99. All rates in Mgal/d, million gallons per day.
28 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

ESTIMATED RETAIL DISTRIBUTION

NONACCOUNT USE

WHOLESALE

PURCHASES, 

WITHDRAWALS, AND

REGIONAL DISTRIBUTION

EXPLANATION

TRANSFERS TO AND FROM STUDY AREA

TRANSFERS WITHIN

STUDY AREA

Kent County Water 

Authority System 

Distribution 

9.881

WITHDRAWALS

Mishnock well #1

0.338

Mishnock well #2

0.363

Spring Lake well #2

0.305

East Greenwich well

0.586 

(import from Hunt Basin)

PROVIDENCE WATER SUPPLY 

BOARD

Interconnection—Clinton Avenue

6.517

Interconnection—Oaklawn Avenue

0.235

WARWICK WATER DEPARTMENT

Interconnection—Bald Hill Road

1.537 

Warwick Water 

Department

(Potowomut)

0.221 

Domestic

2.598

Commercial

0.255

Industrial

0.361 

Agricultural

0.043

Domestic 

1.681

Commercial 

0.455 

Industrial 

0.420

Agricultural 

0.009

TOTAL

2.565

Nonaccount 

Use

3.838

Figure 12. Kent County Water Authority withdrawals, interconnections, purchases, distribution, exports, and estimated water 

uses, central Rhode Island, 1995–99. All rates in Mgal/d, million gallons per day; KCWA, Kent County Water Authority.
Estimated Water Use 29

Table 10. Average withdrawals and purchases for the Kent County Water Authority for June, July, August, and September, 1995–99.

[ProvWater, Providence Water Supply Board; Mgal/d, million gallons per day; --, not applicable]

Kent County Water Authority withdrawals and purchases

Transaction, resource name, 

site type Conveyance action

Transaction rate (Mgal/d)

June July August September

Withdrawal from Mishnock well 1, Mishnock From withdrawal well to 0.234 0.268 0.370 0.274

aquifer, withdrawal well regional distribution

Withdrawal from Mishnock well 2, Mishnock From withdrawal well to .528 .546 .436 .524

aquifer, withdrawal well regional distribution

Withdrawal from Spring Lake well, Mishnock From withdrawal well to .412 .424 .376 .352

aquifer, withdrawal well regional distribution

Withdrawal from East Greenwich well, Hunt From withdrawal well to .877 1.135 1.045 .701

aquifer, regional distribution system regional distribution

Wholesale purchase from From regional 7.479 7.846 7.215 6.453

ProvWater at Clinton, --, distribution to regional 

regional distribution system distribution

Wholesale purchase from From regional .301 .403 .297 .184

ProvWater at Oaklawn, --, distribution to regional 

regional distribution system distribution

Wholesale purchase from Warwick Water From local distribution to 3.000 3.777 3.034 2.016

Department at Bald Hill, --, local distribution regional distribution

system

Kent County Water Authority totals 12.83 14.40 12.77 10.50

[

minor public-supply withdrawals in the North Branch Pawtuxet 

and Northeastern Pawtuxet subbasins, and the minor publicsupply withdrawals in the Scituate Reservoir Complex and 

South Branch Pawtuxet subbasins were each 0.013 Mgal/d. 

Estimated water withdrawals for the individual minor suppliers 

ranged from 0.001 Mgal/d to 0.008 Mgal/d. One minor public 

supplier in the Quinebaug River Basin withdrew an estimated 

0.003 Mgal/d. 

Domestic Water Use

Domestic water use is water used by residential populations served by public supplies or by private wells. To calculate 

the water use for this category, population estimates in Rhode 

Island were multiplied by the water-use coefficients 

71 gal/d/person for self-supply domestic water use and 

67 gal/d/person for public-supply domestic water use. These 

coefficients were based on the 1990 national water-use compilation (Korzendorfer and Horn, 1995). 

Public-Supply Use in the Pawtuxet and Quinebaug 

River Basins

Because water suppliers provide information on populations served within towns rather than within subbasins, census 

coverages available through RIGIS were used to estimate subbasin populations on public supply. The 1990 census blocks, 

which include the domestic populations on private wells, were 

merged with the subbasin coverages. The 1990 self-supply population was subtracted from the total population to obtain the 

public-supply population for the part of each town in each subbasin. The 1990 populations on public and self-supply were 

divided by the total population for the part of each town within 

each subbasin to determine the percentages of public- and selfsupply populations within each subbasin. This method was 

repeated for the 1990 populations on public-wastewater collection and wastewater return flow for domestic users, also known 

as septic systems. The 1995–99 population on self-supply for 

each subbasin was estimated by multiplying the 1990 population by the ratio of growth or decline within each subbasin from 

1995 through 1999 (table 2). The percentages of public- and 

self-supply populations, assumed to be the same for the 

1995–99 study period as for 1990, were applied to the 1995–99 

populations to determine the 1995–99 populations on self-disposal and on public-wastewater collection (table 2). The 

1995–99 populations on public-wastewater collection and selfdisposal of wastewater were then calculated by the same subtraction procedure as above. Because limited withdrawal data 

were available for the 13 minor public suppliers in the basin, the 

water-use coefficient was applied to the populations served by 

each supplier (Korzendorfer and Horn, 1995). 
30 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99ESTIMATED

RETAIL DISTRIBUTION NONACCOUNT USE WHOLESALE

PURCHASES, WITHDRAWALS, RETURN FLOWS, ANDREGIONAL DISTRIBUTION

EXPLANATION

TRANSFERS TO AND FROM STUDY AREA TRANSFERS WITHIN STUDY AREA

A. Scituate Spillway to North Branch Pawtuxet River 

35.25

Discharge through Gatehouse to North Branch Pawtuxet River 11.92

Scituate Reservoir Intake at Gainer Dam 118.0J.P. Holden Purification Plant 70.85

RIPDES Discharge to the North Branch Pawtuxet River 0.638

39.23BASINSPawtuxetMoshassuckNarragansett BayWoonasquatucket

BRISTOL COUNTY WATER AUTHORITY2

0.311INTERCONNECTIONVirginia AvenueBASINNarragansett Bay

Nonaccount Use0.004 Providence Water Supply Board Regional Distribution 

67.03

EAST SMITHFIELD WATER DISTRICT0.758INTERCONNECTIONSDean Avenue Waterman Avenue BASIN Woonasquatucket

KENT COUNTY 

WATER AUTHORITY 

6.705INTERCONNECTIONS Clinton Avenue Oaklawn Avenue BASINS 

Pawtuxet 

Narragansett Bay

WARWICK WATER DEPARTMENT 9.649 INTERCONNECTIONSNatick AvenuePettaconsettBASINSPawtuxetNarragansett Bay

CRANSTON WATER DISTRICT AND JOHNSTON WATER DISTRICT1 

1.009INTERCONNECTIONSGreen Hill RoadSimmonsville AvenueTaylor RoadNardillo RoadCapitolRosewoodBASINPawtuxet

EAST PROVIDENCE 5.484INTERCONNECTION Budlong/Aqueduct Road BASINS Narragansett Bay Ten Mile

LINCOLN WATER2.168INTERCONNECTIONSMineral Spring Avenue Charles StreetBASINS BlackstoneMoshassuckGREENVILLE WATER DISTRICT 0.847INTERCONNECTIONG. Waterman Road BASIN Woonasquatucket

SMITHFIELDWATER DISTRICT0.755INTERCONNECTIONSmithfield RoadBASINS

MoshassuckWoonasquatucketBlackstone

1 Cranston maintained interconnections from 1995–1997; 

import rate was 1.58 Mgal/d. Johnston maintained interconnections from November 1997 through 1999; import rate was 0.62 Mgal/d.

2 Bristol County Water Authority in operation from November 1998 to 

December 1999; import rate was 1.33 Mgal/d.

Figure 13. Providence Water Supply Board A, withdrawals, interconnections, distribution, and estimated water uses, central Rhode Island; and B, retail distribution, 

exports, and estimated water uses, 1995–99. All rates in Mgal/d, million gallons per day.
Estimated Water Use 31

B.

ESTIMATED RETAIL DISTRIBUTION NONACCOUNT USE

EXPLANATION

TRANSFERS TO AND FROM STUDY AREA TRANSFERS WITHIN STUDY AREA

Providence Water Supply BoardRetail Distribution39.23

Domestic11.57Commercial5.589Industrial1.274

TOTAL18.43

Domestic6.563

Industrial1.351

NonaccountUse

Commercial1.351 

11.28

Figure 13. Providence Water Supply Board A, withdrawals, interconnections, distribution, and estimated water uses, central Rhode Island; and 

B, retail distribution, exports, and estimated water uses, 1995–99. All rates in Mgal/d, million gallons per day.—Continued
32 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

Table 11. Withdrawals, discharges, retail sales, and wholesale purchases for the Providence Water Supply Board system in June, July, 

August, and September, 1995–99.

[The Providence Water Supply Board withdraws from the Scituate Reservoir. ProvWater, Providence Water Supply Board; RIPDES, Rhode Island Pollutant 

Discharge Elimination System; Mgal/d, million gallons per day; --, not applicable]

Transaction, resource name, 

site type Conveyance action

Transaction rate (Mgal/d)

June July August September

Intake from Scituate Reservoir, Scituate From intake pipe and surface- 139.9 116.5 99.22 86.53

Reservoir, intake pipe and surface-water water withdrawal

withdrawal

Spillover to North Branch Pawtuxet River, From surface-water withdrawal 41.49 9.195 -- --

North Branch Pawtuxet Basin, surface-water to surface water

return flow

Discharge through gatehouse to North Branch From surface-water withdrawal 10.38 11.21 11.78 10.88

Pawtuxet River, North Branch Pawtuxet to surface water

Basin, surface-water return flow

Intake at J.P. Holton Purification Plant, --, From intake pipe to potable 88.05 96.11 87.44 75.65

potable treatment plant treatment 

RIPDES discharge to North Branch Pawtuxet From potable treatment to .782 .728 .685 .549

River, North Branch Pawtuxet Basin, surface water

discharge pipe

Regional distribution from ProvWater, --, From potable treatment to 83.68 91.52 83.31 71.81

regional distribution system regional distribution

Retail sales from ProvWater, --, local From regional distribution to 47.86 49.23 46.18 40.45

distribution system local distribution

Wholesale purchases by East Smithfield Water From regional distribution to .935 1.077 .914 .783

District, --, local distribution system local distribution

Wholesale purchases by Smithfield Water From regional distribution to .972 1.156 1.016 .862

Supply Board, --, local distribution system local distribution

Wholesale purchases by Greenville Water From regional distribution to 1.208 1.493 1.199 .826

District, --,local distribution system local distribution

Wholesale purchases by Lincoln Water From regional distribution to 2.952 2.853 2.495 2.307

Commission, --, local distribution system local distribution

Wholesale purchases by East Providence Water From regional distribution to 6.740 7.860 6.891 6.320

Department, --, local distribution system local distribution

Wholesale purchases by Cranston/Johnston From regional distribution to 1.479 1.964 1.778 1.485

Water District, --, local distribution system local distribution

Wholesale purchases by Warwick Water From regional distribution to 13.25 16.98 14.80 11.72

Department, --, local distribution system local distribution

Wholesale purchases by Kent County Water From regional distribution to 7.852 8.418 7.533 6.620

Authority, --, regional distribution system regional distribution

Wholesale purchases by Bristol County Water From regional distribution to .436 .484 .505 .439

Authority, --, regional distribution system regional distribution
Estimated Water Use 33

ESTIMATED RETAIL DISTRIBUTION

WHOLESALE

PURCHASES,

WITHDRAWALS, AND

REGIONAL DISTRIBUTION

NONACCOUNT USE

INTERCONNECTION

Potowomut

INTERCONNECTION

Bald Hill Road

Warwick Water

Department

Distribution

9.755

EXPLANATION

TRANSFERS WITHIN

STUDY AREA

TRANSFERS TO AND FROM STUDY AREA

Nonaccount

Use

0.054

(Fire Hydrants)

Nonaccount

Use

0.115

PROVIDENCE

WATER SUPPLY BOARD

9.649

INTERCONNECTIONS

Natick

5.380

Pettaconsett

4.154

KENT

COUNTY WATER

AUTHORITY

0.221

Domestic

3.958

Commerical

0.516

Industrial

0.057

Agricultural

0.020

Domestic

1.094

Agricultural 

0.012 

Industrial

0.356

Commercial

0.470

Nonaccount

Use

1.789

KENT

COUNTY WATER

AUTHORITY

1.537

TOTAL

4.551

Figure 14. Warwick Water Department interconnections, purchases, distribution, exports, and estimated water uses, 

central Rhode Island, 1995–99. All rates in Mgal/d, million gallons per day.
34 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

Public-supply domestic water use in the Pawtuxet River 

subbasins ranged from 0.072 Mgal/d in the Scituate Reservoir 

Complex subbasin to 8.147 Mgal/d in the Northeastern 

Pawtuxet subbasin. One minor public water supplier in the 

Quinebaug River Basin used an estimated 0.003 Mgal/d for 

domestic purposes (table 12). 

Self-Supply Use in the Pawtuxet and Quinebaug River 

Basins

Domestic self-supply water withdrawals and use in the 

Pawtuxet subbasins ranged from 0.118 Mgal/d in the North 

Branch Pawtuxet subbasin to 0.956 Mgal/d in the Scituate Reservoir Complex subbasin (tables 9 and 12). Domestic self-supply water withdrawals and use in the Quinebaug were 0.319 

Mgal/d (tables 9 and 12).

Commercial and Industrial Water Use

Limited data are available on commercial and industrial 

water use from public- and self-supply systems, because withdrawals and use for these categories are not regulated in Rhode 

Island unless the withdrawal point is adjacent to a wetland 

(Rhode Island Department of Environmental Management, 

2001). Commercial and industrial water-use estimates, therefore, were calculated for each town by apportioning the total 

commercial and industrial water uses by the percentage of the 

commercial and industrial land-use areas in each subbasin. 

Consumptive commercial and industrial water use (table 13) is 

assumed to be 10 percent of the total water use (Solley and 

others, 1998). 

Public-Supply Use in the Pawtuxet River Basin

Information on commercial and industrial use of publicsupply water included metered (or reported) and unmetered (or 

estimated) water-use data. If the data were available, public 

suppliers provided the delivery volume and the number of service connections for commercial and industrial water users. In 

some cases, suppliers combined the water amounts supplied to 

commercial and industrial users, but in other cases, the information was not available. Government water use is accounted for 

within the commercial water-use category according to the 

Standard Industrial Classification (SIC) codes; however, government water use was entered as a separate distribution into 

NEWUDS. Because some public-supply district service areas 

are within one or more basins and subbasins, the public-supply 

commercial and industrial water uses were apportioned according to percentages of land-use areas (table 4). Land-use coverages from RIGIS were merged with the water-supply district, 

town, and basin coverages to obtain the percentages of commercial and industrial land use within the supply districts for towns 

served in the Pawtuxet River Basin. Commercial use of publicsupply water ranged from 0.015 Mgal/d in the Scituate Reservoir Complex subbasin to 2.253 Mgal/d in the Northeastern 

Pawtuxet subbasin. Industrial use of public-supply water 

ranged from 0.001 Mgal/d in the Scituate Reservoir Complex 

subbasin to 1.843 Mgal/d in the Northeastern Pawtuxet 

subbasin (table 12). 

Self-Supply Use in the Pawtuxet and Quinebaug River 

Basins

Self-supply commercial and industrial-use estimates were 

calculated from the employee counts published in the RIEDC’s 

“Export/Import Directory” (2000a), “High Tech Industries in 

Rhode Island” (1999), and “Major Employers in Rhode Island” 

(2000b). The numbers of employees in the industrial and commercial sectors for each SIC code were multiplied by the U.S. 

Army Corp of Engineers’ Institute for Water Resources Municipal and Industrial Needs (IWR-MAIN) water-use coefficient 

(in gal/d/person) for each town (table 14) as described in Horn 

(2000). The estimated public-supply commercial and industrial 

water-use rates were subtracted from the total aggregate wateruse rates to obtain the estimated total self-supply use for these 

categories. The total commercial and industrial water-use estimates for towns were disaggregated by basin (table 6) and then 

by subbasin on the basis of the land-use area by town as listed 

in table 3. Self-supply commercial use ranged from less than 

0.001 Mgal/d in the North Branch Pawtuxet subbasin to 0.042 

Mgal/d in the Northeastern Pawtuxet subbasin. Self-supply 

industrial use ranged from 0.009 Mgal/d in the North Branch 

Pawtuxet subbasin to 0.082 Mgal/d in the South Branch 

Pawtuxet subbasin (tables 9 and 12). 

Agricultural Water Use

The estimated agricultural water use (livestock, crop irrigation, and golf-course irrigation) was obtained from information provided by the Department of Agriculture (USDA) 

NRCS, formerly known as the USDA Soil Conservation Service (SCS). The estimate was calculated for each town and then 

disaggregated by state basin and subbasin. Nine percent of withdrawals and use for livestock were assumed to be from surface 

water (streams and ponds) and 82 percent from ground water 

(wells); these livestock water-use rates were previously estimated in a study completed by the SCS (1993). Likewise, 

eighty-one percent of withdrawals and use for irrigation (golf 

courses and crops) were assumed to be from surface water and 

13 percent from ground water (SCS, 1993). The remaining 9 

percent of livestock use and 6 percent of irrigation use were 

assumed to be from public-supply distributions. 

The water-use coefficients for each type of livestock 

(Laura Medalie, U.S. Geological Survey, written commun., 

1995) were multiplied by the number of livestock of each type. 

Because the livestock and crop-irrigation data are reported in 

the 1997 Census of Agriculture at the county level (U.S. Department of Agriculture, 1997a,b), the estimates were disaggregated on the basis of the number of farms in the towns in each
Estimated Water Use 35

.

Table 12. Estimated water supply by town and subbasin in the Pawtuxet River Basin, central Rhode Island, and in the Quinebaug River 

Basin, western Rhode Island, 1995–99.

[Shaded areas are basin totals. All towns are in Rhode Island unless otherwise noted. Mgal/d, million gallons per day; --, not applicable; <0.001, value not 

included in totals]

Town

Domestic

(Mgal/d)

Commercial

(Mgal/d)

Industrial 

(Mgal/d)

Agricultural 

(Mgal/d) Total

(Mgal/d) Public Self Public Self Public Self Public Self

Pawtuxet River Basin

Scituate Reservoir Complex Subbasin

Cranston

Foster

Glocester

Johnston

Scituate

Smithfield

Subbasin total

0.007

.007

--

.029

.029

--

0.003

.171

.200

.038

.538

.006

--

--

--

0.015

--

--

--

0.001

.007

--

.008

--

--

--

--

0.001

--

--

--

0.002

--

--

.012

--

0.001

--

--

<.001

--

--

0.002

.002

.003

.001

.007

<.001

0.013

.183

.210

.084

.594

.006

0.072 0.956 0.015 0.016 0.001 0.014 0.001 0.015 1.090

North Branch Pawtuxet Subbasin

Coventry

Cranston

Scituate

West Warwick

Subbasin total

0.235

.047

.060

.399

0.035

.023

.058

.002

0.003

<.001

.001

.018

--

<0.001

--

--

0.015

.004

.026

.064

0.009

--

--

--

0.003

<.001

<.001

.009

0.003

.005

.003

--

0.303

.079

.148

.492

0.741 0.118 0.022 <0.001 0.109 0.009 0.012 0.011 1.022

South Branch Pawtuxet Subbasin

Coventry

East Greenwich

Exeter

Foster

Scituate

Warwick

West Greenwich

West Warwick

Subbasin total

1.390

.002

<.001

--

--

.001

.050

.850

0.430

.001

.028

.015

.020

--

.113

.005

0.058

--

--

--

--

.001

--

.047

0.004

--

.001

--

--

--

.001

--

0.096

--

--

--

--

--

.017

.114

0.017

--

--

--

--

--

.065

--

0.004

--

--

--

--

<.001

<.001

<.001

0.022

--

.002

.003

.001

--

<.001

--

2.021

.003

.031

.018

.021

.002

.246

1.016

2.293 0.612 0.106 0.006 0.227 0.082 0.004 0.028 3.358

 Northeastern Pawtuxet Subbasin

Cranston

Johnston

Providence

Warwick

West Warwick

Subbasin total

Basin total

4.464

.731

1.605

1.143

.204

0.070

.149

--

<.001

.010

0.689

.199

.767

.588

.010

0.015

.027

--

--

--

0.977

.131

.354

.365

.016

0.011

.004

--

--

--

0.021

.003

--

.019

.008

0.019

.001

--

--

--

6.266

1.245

2.726

2.115

.248

8.147 0.229 2.253 0.042 1.843 0.015 0.051 0.020 12.60

11.25 1.915 2.396 0.064 2.180 0.120 0.068 0.074 18.07

Quinebaug River Basin

Burrillville

Coventry

Exeter

Foster

Glocester

West Greenwich

Basin total

--

0.003

--

--

--

--

0.036 --

.109 --

.006 --

.120 --

.045 --

.003 --

-- --

0.002 --

-- --

<.001 --

.003 --

-- --

--

0.004

--

--

<.001

--

-- <0.001

-- .007

-- --

-- .024

-- .001

-- --

0.036

.125

.006

.144

.049

.003

0.003 0.319 -- 0.005 -- 0.004 -- 0.032 0.363
36 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

.

Table 13. Estimated consumptive water use by town and subbasin in the Pawtuxet River Basin, central Rhode Island, and in the 

Quinebaug River Basin, western Rhode Island, 1995–99.

[Shaded areas are basin totals. All towns are in Rhode Island unless otherwise noted. Mgal/d, million gallons per day; <0.001, value not included in totals; 

--, not applicable]

Town

Domestic (Mgal/d) Commercial (Mgal/d) Industrial (Mgal/d) Agricultural (Mgal/d) Total

Public Self Public Self Public Self Public Se (Mgal/d) lf

Pawtuxet River Basin

Scituate Reservoir Complex Subbasin

Cranston <0.001 0.001 -- -- -- -- 0.001 0.002 0.004

Foster -- .027 -- <0.001 -- <0.001 -- .002 .047

Glocester -- .030 -- .001 -- -- -- .003 .034

Johnston <.001 .010 0.001 -- <0.001 -- <.001 .001 .012

Scituate .002 .083 -- .001 -- .001 -- .007 .094

Smithfield -- .001 -- -- -- -- -- <.001 .001

Subbasin total 0.002 0.152 0.001 0.002 <0.001 0.001 0.001 0.015 0.174

North Branch Pawtuxet Subbasin

Coventry 0.003 0.039 <0.001 -- 0.001 0.001 0.003 0.003 0.050

Cranston .001 .010 <.001 <0.001 <.001 -- <.001 .005 .016

Scituate .001 .017 <.001 -- .003 -- <.001 .003 .024

West Warwick .055 .005 .002 -- .006 -- .009 -- .077

Subbasin total 0.060 0.071 0.002 <0.001 0.010 0.001 0.012 0.011 0.167

South Branch Pawtuxet Subbasin

Coventry 0.033 0.250 0.006 <0.001 0.010 0.002 0.004 0.022 0.327

East Greenwich <.001 .001 -- -- -- -- -- -- .001

Exeter -- .004 -- <.001 -- -- -- .002 .006

Foster -- .002 -- -- -- -- -- .003 .005

Scituate -- .003 -- -- -- -- -- .001 .004

Warwick <.001 <.001 <.001 -- -- -- <.001 -- <.001

West Greenwich <.001 .025 -- <.001 .002 .006 <.001 <.001 .033

West Warwick .122 .006 .005 -- .011 -- <.001 -- .144

Subbasin total 0.155 0.291 0.011 <0.001 0.023 0.008 0.004 0.028 0.520

 Northeastern Pawtuxet Subbasin

Cranston 0.609 0.075 0.069 0.001 0.098 0.001 0.021 0.019 0.893

Johnston .072 .063 .020 .003 .013 <.001 .003 .001 .175

Providence .241 -- .077 -- .035 -- -- -- .353

Warwick .116 .059 .059 -- .037 -- .019 -- .290

West Warwick .030 .002 .001 -- .002 -- .008 -- .043

Subbasin total 1.068 0.199 0.226 0.004 0.185 0.001 0.051 0.020 1.754

Basin total 1.285 0.713 0.240 0.006 0.218 0.011 0.068 0.074 2.615

Quinebaug River Basin

Burrillville -- 0.006 -- -- -- -- -- <0.001 0.006

Coventry -- .017 -- <0.001 -- <0.001 -- .007 .024

Exeter -- .001 -- -- -- -- -- -- .001

Foster -- .018 -- <.001 -- -- -- .024 .042

Glocester -- .007 -- <.001 -- <.001 -- .001 .008

West Greenwich -- .001 -- -- -- -- -- -- .001

Basin total -- 0.050 -- <0.001 -- <0.001 -- 0.032 0.082
Estimated Water Use 37

Table 14. Estimated water use for each 2-digit Standard Industrial Classification code by town in the Pawtuxet and Quinebaug River 

Basins, 1995–99.

[IWR-MAIN coefficient, Institute for Water Resources Municipal and Industrial Needs coefficient in millions of gallons per day per person; Mgal/d, million 

gallons per day; --, not applicable; <0.001, value not used in totals]

2-digit Standard Industrial Classification

category and [code]

IWR-MAIN

coefficient

Estimated water use in Rhode Island towns (Mgal/d)

Burrillville Coventry Cranston East

Greenwich Exeter

Industrial [20-39]

Food [20] 469 0.033 -- 0.162 0.003 --

Textile mills [22] 315 .016 0.022 .008 -- --

Finished apparel [23] 13 -- -- -- -- --

Wood, lumber [24] 78 -- -- -- -- --

Furniture [25] 3 -- -- -- -- --

Paper products [26] 863 -- -- .237 -- --

Printing, publishing [27] 42 -- -- <.001 <.001 --

Chemical products [28] 289 -- .102 .069 -- --

Petroleum refining [29] 1,045 -- -- -- -- --

Rubber [30] 119 .008 -- .150 -- 0.024

Leather [31] 148 -- -- .007 -- --

Stone, clay, glass, and concrete [32] 202 -- -- .141 -- --

Primary metals [33] 178 -- -- .012 .026 --

Fabricated metal [34] 95 .011 -- .066 .002 --

Machinery [35] 58 -- .009 .029 .085 --

Electrical equipment [36] 71 -- -- .035 .072 --

Transportation equipment [37] 63 -- -- -- -- --

Instruments [38] 66 -- .001 .039 .003 --

Jewelry, precious metals [39] 36 -- .008 .040 .003 --

Total industrial [20-39] -- 0.067 0.142 0.995 0.194 0.024

Commercial [40-97]

Transportation, communication, utilities [40-49] 51 -- -- 0.019 0.013 --

Wholesale trade [50-51] 58 0.007 -- .034 -- --

Retail trade [52-59] 58 .007 0.034 .290 .006 --

Finance, insurance, real estate [60-67] 71 -- -- .008 -- --

Services [70-89] 106 .038 .034 .375 .004 0.017

Public administration [91-97] 71 -- -- -- -- --

Total commercial [40-97] -- 0.051 0.068 0.726 0.023 0.017
38 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

Table 14. Estimated water use for each 2-digit Standard Industrial Classification code by town in the Pawtuxet and Quinebaug River 

Basins, 1995–99.—Continued

[IWR-MAIN coefficient, Institute for Water Resources Municipal and Industrial Needs coefficient in millions of gallons per day per person; Mgal/d, million 

gallons per day; --, not applicable; <0.001, value not used in totals]

2-digit Standard Industrial Classification

category and [code]

IWR-MAIN

coefficient

Estimated water use in Rhode Island towns (Mgal/d)

Foster Glocester Johnston Providence Scituate

Industrial [20-39]

Food [20] 469 -- -- 0.002 0.176 --

Textile mills [22] 315 -- -- -- .058 --

Finished apparel [23] 13 -- -- -- .001 --

Wood, lumber [24] 78 0.001 -- -- -- --

Furniture [25] 30 -- -- -- .003 --

Paper products [26] 863 -- -- -- .582 --

Printing, publishing [27] 42 -- -- .001 .069 --

Chemical products [28] 289 -- -- -- .019 --

Petroleum refining [29] 1,045 -- -- -- -- --

Rubber [30] 119 -- -- .025 .044 0.036

Leather [31] 148 -- -- -- .001 .001

Stone, clay, glass, and concrete [32] 202 -- -- .101 -- --

Primary metals [33] 178 -- -- .026 .055 --

Fabricated metal [34] 95 -- -- .006 .125 --

Machinery [35] 58 -- <0.001 <.001 .026 .002

Electrical equipment [36] 71 -- -- .002 .048 --

Transportation equipment [37] 63 -- -- -- .026 --

Instruments [38] 66 -- -- .005 .075 --

Jewelry, precious metals [39] 36 <.001 -- .032 .215 --

Total industrial [20-39] -- 0.001 <0.001 0.200 1.523 0.039

Commercial [40-97]

Transportation, communication, utilities [40-49] 51 -- -- 0.006 0.435 --

Wholesale trade [50-51] 58 <0.001 -- -- .038 --

Retail trade [52-59] 58 -- -- .041 .122 0.008

Finance, insurance, real estate [60-67] 71 -- -- .052 .676 --

Services [70-89] 106 .001 0.031 .247 4.716 .001

Public administration [91-97] 71 -- -- -- .008 --

Total commercial [40-97] -- 0.001 0.031 0.346 5.995 0.009
Estimated Water Use 39

Table 14. Estimated water use for each 2-digit Standard Industrial Classification code by town in the Pawtuxet and Quinebaug River 

Basins, 1995–99.—Continued

[IWR-MAIN coefficient, Institute for Water Resources Municipal and Industrial Needs coefficient in millions of gallons per day per person; Mgal/d, million 

gallons per day; --, not applicable; <0.001, value not used in totals]

2-digit Standard Industrial Classification

category and [code]

IWR-MAIN

coefficient

Estimated water use in Rhode Island towns (Mgal/d)

 Smithfield Warwick West

 Greenwich

West

Warwick

Industrial [20-39]

Food [20] 469 0.077 0.009 -- --

Textile mills [22] 315 -- .031 0.009 0.090

Finished apparel [23] 13 -- -- -- --

Wood, lumber [24] 78 -- -- -- --

Furniture [25] 30 .003 .017 -- --

Paper products [26] 863 -- .022 -- --

Printing, publishing [27] 42 -- .007 -- --

Chemical products [28] 289 -- .010 .068 .147

Petroleum refining [29] 1045 -- -- -- --

Rubber [30] 119 -- .004 .003 .015

Leather [31] 148 -- -- -- --

Stone, clay, glass, and concrete [32] 202 .006 -- -- .015

Primary metals [33] 178 .011 .039 -- --

Fabricated metal [34] 95 .001 .050 -- .060

Machinery [35] 58 .005 .026 .058 .008

Electrical equipment [36] 71 .003 .146 -- .031

Transportation equipment [37] 63 .002 -- -- --

Instruments [38] 66 .032 .038 -- --

Jewelry, precious metals [39] 36 .019 .054 -- .001

Total industrial [20-39] -- 0.159 0.453 0.138 0.367

Commercial [40-97]

Transportation, communication, utilities [40-49] 51 -- 0.075 0.001 0.020

Wholesale trade [50-51] 58 -- .008 -- --

Retail trade [52-59] 58 0.030 .363 -- .006

Finance, insurance, real estate [60-67] 71 .076 .166 -- .066

Services [70-89] 106 .143 .892 -- .014

Public administration [91-97] 71 -- -- -- --

Total commercial [40-97] -- 0.249 1.504 0.001 0.106
40 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

county and the percentage of agricultural land use in each town 

and subbasin. The livestock water-use estimates represent a 

year-round usage. Although it is estimated that 60 percent of 

livestock water use is consumed and 40 percent is returned to 

ground water (Horn and others, 1994), this distinction was negligible for the Pawtuxet and Quinebaug River Basins. Thus, 

agricultural water use was assumed to be 100 percent consumed 

(table 13) (Horn and others, 1994). Livestock water use 

accounted for about 13 percent of the agricultural water withdrawals and about 0.01 percent of the total water withdrawals 

during the study period, and thus was a minor component of 

water use in the Pawtuxet River Basin. In the Quinebaug River 

Basin, livestock water withdrawals accounted for 6.3 percent of 

the agricultural withdrawals and about 0.5 percent of the total 

water withdrawals.

Crop and golf-course irrigation were estimated on the 

basis of the assumption that the percentage of agricultural landuse area for each town is equal to the percentage of the total 

town agricultural land-use area in the county. The irrigated 

town acreage determined from the estimation was then subdivided by basin and subbasin. For irrigated acreage in the Pawtuxet River Basin, it was assumed that 1 in/week/acre of water 

(an average of 0.143 in/day/acre) was needed to irrigate crop 

land (Laura Medalie, U.S. Geological Survey, written commun., 2000). The monthly water deficit was determined by subtracting the average monthly rainfall from the 0.143 in/day/acre 

needed for crop irrigation. Yardages for the golf courses were 

collected from the websites WorldGolf.com (2002) and GolfCourse.com (2002). The coefficient of 0.0116 Mgal/d per 1,000 

yards (Laura Medalie, U.S. Geological Survey, written commun., 2000) was applied to the golf-course areas in the towns in 

the Pawcatuck Basin (Wild and Nimiroski, 2004) and was used 

in this study. The coefficient used for the 2000 water-use compilation for Massachusetts was comparable at 0.0117 Mgal/d 

per 1,000 yards (Wild and Nimiroski, 2004). According to the 

SCS (1993), most of the irrigation occurred during June, July, 

and August. There was no crop and golf-course irrigation in the 

Quinebaug River Basin during the study period.

Self-supply agricultural water use was estimated by town 

and disaggregated by basin and subbasin. In the Pawtuxet River 

Basin, self-supply water withdrawals and use for agriculture 

ranged from 0.011 Mgal/d in the North Branch Pawtuxet subbasin to 0.028 Mgal/d in the South Branch Pawtuxet subbasin 

(tables 9 and 12). In the Quinebaug River Basin, self-supply 

water withdrawals and use for agriculture ranged from less than 

0.001 Mgal/d in Burrillville to 0.024 Mgal/d in Foster (tables 9 

and 12). Agricultural water withdrawals and use in the 

Quinebaug River Basin were 0.032 Mgal/d (tables 9 and 12). 

Return Flow and Interbasin Transfers

In Rhode Island, commercial and industrial dischargers are 

required to report to the RIDEM Office of Water Resources the 

rates of water returned to the environment. These dischargers, 

referred to as Rhode Island Pollutant Discharge Elimination 

Systems (RIPDES), return wastewater to surface water (usually 

to rivers), or in some cases, to the ground-water system. In addition, local and regional facilities that treat wastewater are 

required to report wastewater discharges into rivers in Rhode 

Island. Domestic, commercial, and industrial disposers who use 

septic systems, which create inflow to the ground-water system, 

are not required to report discharges. For the Pawtuxet River 

Basin, the total metered RIPDES return flow was 5.903 Mgal/d, 

and the total metered wastewater from treatment facilities was 

20.54 Mgal/d (table 15). The return flow from RIPDES sites 

and WWTFs totaled 26.28 Mgal/d to surface water, and 0.163 

Mgal/d to ground water. The estimated return flow from septic 

systems was 4.031 Mgal/d for domestic disposers, 0.058 

Mgal/d for commercial disposers, and 0.109 Mgal/d for industrial disposers (table 15). Therefore, the Pawtuxet River Basin 

total estimated ground-water return flow was 4.361 Mgal/d for 

the study period. The estimated return flow from septic systems, 

the only return flow in the Quinebaug River Basin, was 0.274 

Mgal/d for domestic disposers, 0.005 Mgal/d for commercial 

disposers, and 0.004 Mgal/d for industrial disposers (table 15). 

Interbasin transfers include imports and exports of wastewater and potable water to and from a basin or subbasin. Wastewater is an import, or a gain to the Pawtuxet River Basin, if it is 

collected in another basin or subbasin and conveyed to the Pawtuxet River Basin for discharge. Wastewater is an export, or a 

loss to the basin, when it is collected and processed in the basin 

but is returned to the environment outside the basin. 

Site-Specific Return Flow in the Pawtuxet River Basin

Some RIPDES systems are required to report their discharges to RIDEM. Return-flow data were collected from 

RIDEM for these small systems — for example, wastewatertreatment plants (Horn and Craft, 1991) — in the Pawtuxet 

River Basin (table 16). Return flows are conveyed by discharge 

pipes that dispose water used during industrial and commercial 

processes. Total RIPDES discharges in the Pawtuxet River 

Basin were 5.903 Mgal/d, and ranged from 0.001 Mgal/d in the 

Scituate Reservoir Complex subbasin to 4.479 Mgal/d in the 

South Branch Pawtuxet subbasin (tables 15 and 16).

Monthly data were collected for wastewater-treatment 

facilities in or serving the town populations in the Pawtuxet 

River Basin (table 17), including the Cranston Water Pollution 

Control Facility, the Warwick WWTF, the West Warwick 

Regional WWTF, and the Narragansett Bay Commission Fields 

Point Facility. Cranston, Warwick, and West Warwick wastewater is collected in the Pawtuxet River Basin and in the adjacent West Narragansett Bay Basin, and the treated return flow 

is discharged to the Pawtuxet River in the Northeastern Pawtuxet subbasin. Average discharges to the Pawtuxet River were 

11.69 Mgal/d from the Cranston system, 3.642 Mgal/d from the 

Warwick system, and 5.204 Mgal/d from the West Warwick 

system. These totals include wastewater collected in the Pawtuxet River Basin and imported from outside of the basin. An 

estimated 3.092 Mgal/d of wastewater is collected from the 

parts of Johnston and Providence in the Pawtuxet River Basin 

and exported to the adjacent West Narragansett Bay Basin 

(table 17). 
Estimated Water Use 41

Table 15. Estimated public- and self-disposed domestic, commercial, industrial, and metered return flow by subbasin in the Pawtuxet 

River Basin, central Rhode Island, and in the Quinebaug River Basin, western Rhode Island, 1995–99.

[Shaded areas are basin totals. Public disposal, wastewater collection to treatment plant; Self-disposal, inflow to ground water; RIPDES and WWTFs, inflow to 

surface water; RIPDES, Rhode Island Pollutant Discharge Elimination System; WWTF, wastewater-treatment facilities; Mgal/d, million gallons per day; <0.001, 

value not included in totals; --, not applicable]

Town

Domestic disposal

(Mgal/d)

Commercial disposal

(Mgal/d)

Industrial disposal

(Mgal/d)

Metered return flow

(Mgal/d)

Total selfdisposal and

return flow

(Mgal/d) Public Self Public Self Public Self RIPDES WWTF

Pawtuxet River Basin

Scituate Reservoir Complex Subbasin

Cranston 0.001 0.008 -- -- -- -- -- -- 0.008

Foster -- .151 -- 0.001 -- 0.002 -- -- .154

Glocester -- .170 -- .006 -- -- -- -- .176

Johnston .002 .056 0.014 -- 0.001 -- -- -- .056

Scituate .013 .469 -- .007 -- .011 0.001 -- .488

Smithfield -- .005 -- -- -- -- -- -- .005

Subbasin total 0.016 0.859 0.014 0.014 0.001 0.013 0.001 -- 0.887

North Branch Pawtuxet Subbasin

Coventry 0.018 0.223 0.003 -- 0.014 0.008 0.020 -- 0.251

Cranston .006 .055 -- -- .004 -- -- -- .055

Scituate .008 .095 .001 -- .023 -- .637 -- .732

West Warwick .315 .028 .016 -- .058 -- .028 -- .056

Subbasin total 0.347 0.401 0.020 -- 0.099 0.008 0.685 -- 1.094

South Branch Pawtuxet Subbasin

Coventry 0.188 1.419 0.052 0.004 0.086 0.015 4.449 -- 5.887

East Greenwich <.001 .003 -- -- -- -- -- -- .003

Exeter -- .024 -- .001 -- -- -- -- .025

Foster -- .013 -- -- -- -- -- -- .013

Scituate -- .017 -- -- -- -- -- -- .017

Warwick <.001 .001 .001 -- -- -- -- -- .001

West Greenwich .001 .139 -- .001 .015 .059 -- -- .199

West Warwick .693 .035 .042 -- .103 -- .030 -- .065

Subbasin total 0.882 1.651 0.095 0.006 0.204 0.074 4.479 -- 6.210

Northeastern Pawtuxet Subbasin

Cranston 3.513 0.423 0.620 0.014 0.879 0.010 0.018 11.69 12.16

Johnston .405 .356 .179 .024 .118 .004 .018 -- .402

Providence 1.364 -- .690 -- .319 -- -- -- --

Warwick .658 .332 .529 -- .329 -- .702 3.642 4.676

West Warwick .172 .009 .009 -- .014 -- -- 5.204 5.213

Subbasin total 6.112 1.120 2.027 0.038 1.659 0.014 0.738 20.54 22.45

Basin total 7.357 4.031 2.156 0.058 1.963 0.109 5.903 20.54 30.64

Quinebaug River Basin

Burrillville -- 0.031 -- -- -- -- -- -- 0.031

Coventry -- .095 -- 0.002 -- 0.004 -- -- .101

Exeter -- .005 -- -- -- -- -- -- .005

Foster -- .101 -- <.001 -- -- -- -- .101

Glocester -- .039 -- .003 -- <.001 -- -- .042

West Greenwich -- .003 -- -- -- -- -- -- .003

Basin total -- 0.274 -- 0.005 -- 0.004 -- -- 0.283
42 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

1 The receiving water body is not specified in the NEWUDS database. In this report, return flows were assumed to be discharged directly to the local aquifer 

and were treated as such in the calculation of water budgets.

2 No data for period of study (1995–99).

Table 16. Return flows by subbasin for the Rhode Island Pollutant Discharge Elimination System sites in the Pawtuxet River Basin, 

central Rhode Island, 1995–99.

[Shaded area represents basin total. Reference Number: The identifier for sites shown on figure 8. SIC, Standard Identification Code; Mgal/d, million gallons per 

day; MHRH, Mental Health, Retardation and Hospitals; RI, Rhode Island; --, unknown]

Return-flow site Reference

number

Town

Discharge

permit

number

Receiving

water body

SIC

code

Return flow

1995–99

(Mgal/d)

Pawtuxet River Basin

Scituate Reservoir Complex Subbasin

Kenyon Oil Company 1 Scituate RI0023191 --1 5541 0.001

Subbasin total 0.001

North Branch Pawtuxet Subbasin

Providence Water Supply Board 2 Scituate RI0021601 North Branch Pawtuxet River 4941 0.637

Arkwright, Inc. 3 Coventry RI0000035 North Branch Pawtuxet River 3081 .020

Victor Electric Wire 4 West Warwick RI0001473 North Branch Pawtuxet River 3357 .028

Subbasin total 0.685

South Branch Pawtuxet Subbasin

Shell Service Station 5 Coventry RI0021822 --1 5541 <0.001

Garland Industries 6 Coventry RI0021075 South Branch Pawtuxet River 3951 --2

Clarient Corporation 7 Coventry RI0000132 South Branch Pawtuxet River 2865 4.449

Concordia Manufacturing 8 Coventry RI0000981 South Branch Pawtuxet River 2282 <.001

Coventry Narrow Fabrics 9 Coventry RI0021580 South Branch Pawtuxet River 2241 <.001

Original Bradford Soap Works 10 West Warwick RI0000248 South Branch Pawtuxet River 2841 .030

Subbasin total 4.479

Northeastern Pawtuxet Subbasin

Medical Homes of Rhode Island 11 Johnston RI0020168 Dry Brook 8051 0.018

Coastal Food Service 12 Cranston RI0021687 Print Works Pond 3589 .001

Merit Oil of Rhode Island, Inc. 13 Cranston RI0022110 --1 5541 <.001

Leonard Valve Company, Inc. 14 Cranston RI0021563 --1 3491 .008

EG&G Sealol 15 Cranston RI0000396 Pawtuxet River 3491 .007

Chem Pak Corp 16 Cranston RI0021156 Pawtuxet River 2812 .001

RI Department of MHRH 17 Cranston RI0020176 Pawtuxet River 8063 .001

Leviton Manufacturing 18 Warwick RI0021377 Three Ponds Brook 3643 .547

Kenney Manufacturing 19 Warwick RI0023027 --1 2591 .155

Rhode Island Mall 20 Warwick RI0001546 Pawtuxet River 7389 <.001

Subbasin total 0.738

Basin total 5.903
Estimated Water Use 43

1Wastewater imported from outside the Pawtuxet River Basin, 12.283 Mgal/d.

2Wastewater exported from the Pawtuxet River Basin to the Narragansett Bay Drainage Basin, 3.092 Mgal/d.

Table 17. Return flow from wastewater-treatment facilities within and outside of the Pawtuxet River Basin, central Rhode Island, 

1995–99.

[Reference letter: Identifier used on fig. 8. Mgal/d, million gallons per day] 

Wastewater-treatment facility Reference 

letter

Discharge

permit

number

Receiving water body

(subbasin or basin)

Average

discharge

1995–99

(Mgal/d)

Return flow to the Pawtuxet River Basin

Cranston Water Pollution-Control Facility A RI0100013 Pawtuxet River

(Northeastern Pawtuxet Subbasin)

11.69

Warwick Wastewater-Treatment Facility B RI0023141 Pawtuxet River

(Northeastern Pawtuxet Subbasin)

3.642

West Warwick Regional Wastewater-Treatment 

Facility

C RI0100153 Pawtuxet River

(Northeastern Pawtuxet Subbasin)

5.204

Total 120.54

Return flow outside of the Pawtuxet River Basin

Narragansett Bay Commission-Fields Point Regional 

Wastewater-Treatment Facility2

D RI0100315 Narragansett Bay 

(West Narragansett Bay Drainage 

Basin)

55.44

Total 55.44

Aggregate Return Flow in the Pawtuxet and Quinebaug 

River Basins

Aggregate return flow was estimated for domestic, industrial, and commercial water use. Domestic populations on septic 

systems were assumed to return 85 percent of their wastewater 

to ground water and to consume 15 percent of the water withdrawn (Solley and others, 1998). To estimate the rate of domestic self-disposal of wastewater, the population was multiplied 

by the water-use coefficient for self-supply water use 

(71 gal/d/person), converted to Mgal/d, and multiplied by 

85 percent. Domestic rates of self-disposal of wastewater in the 

Pawtuxet River Basin ranged from 0.401 Mgal/d in the North 

Branch Pawtuxet subbasin to 1.651 Mgal/d in the South Branch 

Pawtuxet subbasin; in the Quinebaug River Basin, the rate was 

0.274 Mgal/d (table 15). It is estimated that 90 percent of industrial and commercial return flow is disposed to ground water 

and 10 percent is consumed (Horn, 2000). Commercial rates of 

self-disposal of wastewater in the Pawtuxet River Basin ranged 

from none in the North Branch Pawtuxet subbasin to 0.038 

Mgal/d in the Northeastern Pawtuxet subbasin; in the 

Quinebaug River Basin, the rate was 0.005 Mgal/d. Industrial 

rates of self-disposal of wastewater in the Pawtuxet River Basin 

ranged from 0.008 Mgal/d in the North Branch Pawtuxet subbasin to 0.074 Mgal/d in the South Branch Pawtuxet subbasin; in 

the Quinebaug River Basin, the rate was 0.004 Mgal/d

(table 15). Total consumptive water-use rates in the Pawtuxet 

River Basin ranged from 0.167 Mgal/d in the North Branch 

Pawtuxet subbasin to 1.754 Mgal/d in the Northeastern 

Pawtuxet subbasin, and the rate for the Quinebaug River Basin 

was 0.082 Mgal/d (table 13). 

Interbasin Transfers in the Pawtuxet River Basin

The public water supply withdrawn from the Scituate Reservoir Complex subbasin by ProvWater supplied almost all of 

the other basins in Rhode Island, including the Blackstone, the 

Moshassuck, the Woonasquatucket, the Narragansett Bay, and 

the Westport Basins; only the Quinebaug, the Pawcatuck, and 

the South Coastal Basins were not supplied by the Scituate Reservoir. In addition, withdrawals from the Kent County Water 

Authority supplied areas outside of the Pawtuxet River Basin. 

Of the major public-supply withdrawals from the Pawtuxet 

River Basin, about 22 percent were used (domestic, commercial, industrial, and agricultural uses) in the Pawtuxet River 

Basin, and about 51 percent were exported to other basins in 

Rhode Island (fig. 15). The remaining water use was classified 

as nonaccount. Some of the water exported from the basin was 

returned to the basin as wastewater. A comparison of the total 

water withdrawals from the basin to the total use and nonaccount water losses resulted in a net export of 48.48 Mgal/d of 

potable water from the Pawtuxet River Basin (table 18).
44 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

Estimated Major 

Public-Supply 

Distributions 

(Johnston, KCWA,

ProvWater, 

and Warwick) 

15.72

ProvWater

10.34

Major Public-Supply 

Withdrawals1

71.86

ProvWater 

18.52

2.565

Warwick Water 

Department 

4.551

EXPLANATION

TRANSFERS TO AND FROM STUDY AREA

TRANSFERS WITHIN STUDY AREA

ProvWater

and KCWA

WHOLESALE

ESTIMATED 

RETAIL

ESTIMATED 

RETAIL

ESTIMATED 

RETAIL

KCWA2

1

 Net water withdrawals from major public

suppliers. Total withdrawals from ProvWater

at the Scituate Reservoir were 118.0 Mgal/d,

where 47.17 Mgal/d was returned to the

North Branch Pawtuxet River from the 

spillway (35.25 Mgal/d) and the 

gatehouse (11.92 Mgal/d). 

2

 Net water exported from KCWA.

Figure 15. Public-supply withdrawals and estimated exports from the Pawtuxet River Basin, central Rhode Island, 1995–99. 

All rates in Mgal/d, million gallons per day. [ProvWater, Providence Water Supply Board; KCWA, Kent County Water 

Authority]
Estimated Water Use 45

Within the water balance of withdrawals, use by category, 

nonaccount use, consumptive use, and return flows, a percent 

error can be attributed to the addition of metered (or reported) 

and estimated water-use components for each category. Publicsupply withdrawals are metered (or reported), for example, but 

water use by subbasin is estimated, and then the return flow is 

metered (or reported) and estimated. Similarly, RIPDES data 

are metered (or reported), but the rates of withdrawal and use 

are estimated.

Wastewater is collected from the Pawtuxet River Basin 

and outside the basin, and then it is processed and returned to 

the Pawtuxet River from the towns of Cranston, Warwick, and 

West Warwick. Wastewater from the Pawtuxet River Basin is 

also exported in Johnston and Providence to the Narragansett 

Bay Basin, where the wastewater is processed and returned to 

Narragansett Bay (fig. 16). Estimated rates of publicly disposed 

industrial and commercial water were used to determine wastewater imports and exports. In the Pawtuxet River Basin, the net 

import of wastewater was 15.19 Mgal/d (table 18). The only 

exports from the Quinebaug River Basin are losses from consumptive water use, and were 0.136 Mgal/d (table 19). 

Table 18. Summary of estimated water withdrawals, imports, exports, use, consumptive use, and return flow in the Pawtuxet River 

Basin, central Rhode Island, 1995–99. 

[Nonaccount: A loss of water through the system. Consumptive use: A basin export. Net import and exports: The sum of the potable water and wastewater 

imports and exports; does not include nonaccount and consumptive water uses. AG, agricultural; COM, commercial; DOM, domestic; IND, industrial; 

Mgal/d, million gallons per day; <0.001, values not included in town and subbasin totals; +, potable distribution and wastewater imported to subbasin and basin;

-, potable distribution and wastewater exported from subbasin and basin; --, not applicable]

Water Total water use, Return flow withdrawals Potable Wastewater Net public and self

wat (Mgal/d) er Consump- imports (+) imports (+) (Mgal/d) (Mgal/d)

Subbasin imports (+) tive use and and

Use (DOM, Public and exports (-) Nonaccou (Mgal/d) exports (-) exports (-) nt Surface Ground COM, IND, (Mgal/d) (Mgal/d) (Mgal/d) and self (public use) water water AG)

Scituate Reservoir 71.87 -70.77 1.090 0.011 0.174 -- 0.887 -0.029 -70.80

Complex

North Branch .138 +1.358 1.022 .474 .167 0.685 .409 +.240 +1.598

Pawtuxet

South Branch 1.747 +3.072 3.358 1.461 .520 4.479 1.731 +3.372 +6.444

Pawtuxet

Northeastern .306 +17.86 12.60 5.563 1.754 21.12 1.335 +11.61 +29.47

Pawtuxet

Pawtuxet River 74.06 -48.48 18.07 7.509 2.615 26.28 4.362 +15.19 -33.29

Basin total
46 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

EXPLANATION

TRANSFERS TO AND FROM STUDY AREA

TRANSFERS WITHIN STUDY AREA

Public Wastewater 

Facility Discharge to the 

Pawtuxet River Basin 

(from the Cranston 

WPCF, Warwick WWTF, 

and West Warwick 

WWTF) 

20.54 

 Estimated Public Wastewater 

Exported from the Pawtuxet River 

Basin (Johnston, Cranston, and 

Providence) to the Narragansett Bay 

Commission – Fields Point Facility

 3.092

Estimated Public Wastewater 

Imported to the Pawtuxet 

River Basin (from the 

Cranston WPCF, Warwick 

WWTF, and West Warwick 

Regional WWTF) 

 12.283 

Estimated Public 

Wastewater Collection in 

the Pawtuxet River Basin 

8.253 

Figure 16. Estimated public wastewater collection, discharge, and estimated exports from the Pawtuxet River Basin, 

central Rhode Island, 1995–99. All rates in Mgal/d, million gallons per day. [WPCF, Water Pollution Control Facility; 

WWTF, Wastewater Treatment Facility]
Estimated Water Availability in the Summer 47

Table 19. Summary of estimated water withdrawals, imports, exports, use, consumptive use, and return flow in the Quinebaug River 

Basin, western Rhode Island, 1995–99. 

[Consumptive use: A basin export. AG, agricultural; COM, commercial; DOM, domestic; IND, industrial; Mgal/d, million gallons per day; <0.001, values not 

included in town and subbasin totals; +, potable distribution and wastewater imported to subbasin and basin; -, potable distribution and wastewater exported from

subbasin and basin; --, not applicable]

Water Wastewater Net Potable water Total water use Return flow withdrawals Consump- imports (+) imports (+) (Mgal/d) (Mgal/d) imports (+) and (Mgal/d) Subbasin tive use and and

exports (-) (Mgal/d) exports (-) exports (-) Self-supply Surface Ground (Mgal/d) Self-supply (Mgal/d) (Mgal/d) (DOM, COM, IND, AG) water water

Burrillville1 0.036 -- 0.036 0.006 -- 0.031 -- --

Coventry .125 -- .125 .024 -- .101 -- --

Exeter .006 -- .006 .001 -- .005 -- -- 1 Foster .198 -- .198 .096 -- .101 -- --

Glocester1 .049 -- .049 .008 -- .042 -- --

West Greenwich1 .003 -- .003 .001 -- .003 -- --

Basin total 0.417 -- 0.417 0.136 -- 0.283 -- --

1Differences between the total water use and the sum of the consumptive use and the wastewater return flow are a result of rounding.

Estimated Water Availability in the Summer

During periods of little or no precipitation, streamflow is 

primarily sustained from surface-water storage (lakes and reservoirs) and from ground-water discharge; direct runoff is 

assumed to be negligible. Water withdrawals are often higher 

during the summer, and precipitation and ground-water discharge may be lower in the summer than the annual average. 

Therefore, it was important to estimate the amount of available 

water and to compare it to the withdrawals in the study area. 

Water-availability estimates that are made from base-flow calculations are conservative because actual streamflows generally 

are greater than base flow except during periods of no recharge 

from precipitation. 

Because most of the study area is ungaged and records 

from stations in the study area are affected by ground-water 

withdrawals, estimates of available water had to be based on 

streamflows measured at stream-gaging stations in nearby 

basins. First, index stations were chosen whose upstream areal 

percentages of sand and gravel deposits and till deposits are 

similar to those in the study area. The Branch River at Forestdale stream-gaging station (01111500) was the index station 

used to determine water availability in the Scituate Reservoir 

Complex and North Branch Pawtuxet subbasins in the Pawtuxet 

River Basin and in the Quinebaug River Basin (fig. 8). The 

Nooseneck River at Nooseneck stream-gaging station 

(01115630) was the index station used to determine water availability in the South Branch Pawtuxet and Northeastern Pawtuxet subbasins of the Pawtuxet River Basin (table 20). Second, 

the hydrograph-separation application PART (Rutledge, 1993, 

1998) was applied to the records for the two index stations to 

determine the 75th, 50th, and 25th percentiles of base flow for 

June, July, August, and September. The 75th, 50th, and 25th 

percentiles of base flow and these base flows minus the 7Q10 

and ABF low flows (called the 7Q10 and ABF scenarios) were 

calculated (table 21). Third, these base flows were apportioned 

according to the contributions of base flow from sand and 

gravel deposits and of till deposits upstream of the two index 

stations to give base flows per unit area in Mgal/d/mi2. Contributions of base flow from stratified sand and gravel deposits 

and till deposits for the index stations used in this assessment 

were based on previous USGS work for five index stations in 

the Pawcatuck Basin (Wild and Nimiroski, 2004). The regression equation 

y = (0.4) e (x)(1.38), (1)

where 

y = percentage of base-flow contribution from sand and 

gravel deposits at the index station, and 

x = sand and gravel area divided by the total drainage area 

at the index station,

was used to estimate base-flow contributions from sand and 

gravel deposits for the index stations, for which the flow contributions by deposit were unknown. The percentages of baseflow contributions from sand and gravel deposits were estimated to be 60 percent for the Branch River at Forestdale and 

63 percent for the Nooseneck River at Nooseneck stations. The 

base flow for each deposit was divided by the area of each 

deposit upstream of each index station. The resulting values are 

estimates of the base flows per unit area in Mgal/d/mi2

 for the 

sand and gravel and for the till areas upstream of the stations 

(table 22). Finally, the flow per unit area for each type of deposit 

at each index station was multiplied by the area of the same type 
48 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

of deposit in the study-area subbasins assigned to each index 

station. The gross yield from ground water for each subbasin 

was defined as the sum of the base-flow contributions from the 

two types of surficial deposits. The available water was defined 

for the same three scenarios as for the index stations. Ratios of 

water withdrawn to water available were calculated for each 

subbasin. 

Table 20. U.S. Geological Survey stream-gaging stations and minimum streamflows used in the analysis of water availability in the 

Pawtuxet River Basin, central Rhode Island, and in the Quinebaug River Basin, western Rhode Island, 1995–99.

[Stations are shown on fig. 8. Water years are from October to September and may differ from the period of record in the 2000 Water Data Report for 

Massachusetts and Rhode Island (Socolow and others, 2001). 7Q10, 7-day, 10-year low flow; ABF, Aquatic Base Flow, based on the median of the August 

monthly means; USGS, U.S. Geological Survey; Mgal/d, million gallons per day]

USGS

stream-gaging

station number

Station name Drainage area

(mi2

)

Annual 

mean flow

(Mgal/d)

[calendar years] 

Minimum flows (Mgal/d)

7Q10 ABF

[water years] [calendar years]

01111500 Branch River at Forestdale, RI 91.2 116.4 7.694 25.09

[1957–99] [1957–99] [1957–99]

01115630 Nooseneck River at Nooseneck, RI 8.28 12.28 .821 2.910

[1964–80] [1964–80] [1964–80]

Table 21. Summer gross yields for the index stream-gaging stations used in the water-availability analysis in the Pawtuxet River Basin, 

central Rhode Island, and Quinebaug River Basin, western Rhode Island.

[7Q10, 7-day, 10-year low flow; ABF, Aquatic Base Flow, based on the median of the August monthly means; Mgal/d, million gallons per day; --, values less than

zero and not used]

Estimated gross yield Estimated gross yield minus 7Q10 Estimated gross yield minus ABF

Month (Mgal/d) (Mgal/d)

75th 50th 25th

(Mgal/d)

75th 50th 25th 75th 50th 25th

percentile percentile percentile percentile percentile percentile percentile percentile percentile

Branch River at Forestdale stream-gaging station

June 73.47 47.04 35.15 65.77 39.35 27.45 48.38 21.95 10.06

July 34.78 26.60 17.39 27.09 18.90 9.696 9.693 1.510 --

August 29.67 21.48 13.30 21.97 13.79 5.604 4.578 -- --

September 35.15 23.78 16.12 27.45 16.09 8.426 10.06 -- --

Nooseneck River at Nooseneck stream-gaging station

June 10.03 7.246 6.046 9.196 6.412 5.213 7.152 4.368 3.169

July 4.737 3.622 2.694 3.903 2.789 1.860 1.860 .745 --

August 4.551 2.554 1.811 3.717 1.721 .978 1.673 -- --

September 3.551 3.071 2.255 2.718 2.238 1.422 .674 -- --
Estimated Water Availability in the Summer 49

Table 22. Estimated gross yields; gross yields minus the 7-day, 10-year low flow; and gross yields minus the Aquatic Base Flow per unit 

area for the two index stations used to determine water availability for June, July, August, and September in the Pawtuxet River Basin,

central Rhode Island, and the Quinebaug River Basin, western Rhode Island.

[Estimated gross yields based on base flow from the Branch River at Forestdale, RI, stream-gaging station for the period 1957–99. Estimated gross yields based

on base flow from the Nooseneck River at Nooseneck, RI, stream-gaging station for the period 1964–80. 7Q10, 7-day, 10-year low flow; ABF, Aquatic Base 

Flow; Mgal/d, million gallons per day; --, values at station less than zero and not used]

Month

Estimated gross yield 

per unit area

(Mgal/d/mi2)

Estimated gross yield minus 7Q10 

per unit area

(Mgal/d/mi2)

Estimated gross yield minus ABF 

per unit area

(Mgal/d/mi

2

)

75th

percentile

50th

percentile

25th

percentile

75th

percentile

50th

percentile

25th

percentile

75th

percentile

50th

percentile

25th

percentile

Branch River at Forestdale stream-gaging station

Yields from sand and gravel deposits estimated from base flow

June 1.666 1.067 0.797 1.492 0.892 0.623 1.097 0.498 0.228

July .789 .603 .541 .614 .429 .220 .220 .034 --

August .673 .487 .302 .498 .313 .127 .104 -- --

September .797 .539 .366 .623 .365 .191 .228 -- --

Yields from till deposits estimated from base flow

June 0.454 0.291 0.217 0.406 0.243 0.170 0.299 0.136 0.062

July .215 .164 .147 .167 .117 .060 .060 .009 --

August .183 .133 .082 .136 .085 .035 .028 -- --

September .217 .147 .100 .170 .099 .052 .062 -- --

Nooseneck River at Nooseneck stream-gaging station

Yields from sand and gravel deposits estimated from base flow

June 2.180 1.575 1.314 1.999 1.394 1.133 1.555 0.950 0.689

July 1.030 .787 .586 .849 .606 .404 .404 .162 --

August .989 .555 .394 .808 .374 .213 .364 -- --

September .772 .668 .490 .591 .486 .309 .146 -- --

Yields from till deposits estimated from base flow

June 0.689 0.460 0.384 0.632 0.407 0.331 0.492 0.277 0.201

July .326 .230 .171 .268 .177 .118 .128 .047 --

August .313 .162 .115 .256 .109 .062 .115 -- --

September .244 .195 .143 .187 .142 .090 .046 -- --
50 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

Pawtuxet River Basin

In the Pawtuxet River Basin, water availability was calculated at the 75th, 50th, and 25th percentiles for the gross-yield 

scenario, the 7Q10 scenario, and the ABF scenario (table 23). 

The gross-yield value is equal to the estimated ground water 

available in the North Branch Pawtuxet, South Branch Pawtuxet, and Northeastern Pawtuxet subbasins. Estimated gross 

yields and gross yields for the 7Q10 scenarios were lower for 

August at the 50th and 25th percentiles. The water-availability 

rates by subbasin from sand and gravel deposits and till deposits 

are illustrated in figures 17 and 18, respectively. Although 

water availability was greater statewide in July than in August, 

more water was withdrawn in July than in August (table 24). 

Basin withdrawal-to-availability ratios at the 75th percentiles were highest in July for all three scenarios (table 25). 

Although the ratios were higher in July for the Scituate Reservoir Complex subbasin and in August for the North Branch 

Pawtuxet, South Branch Pawtuxet, and Northeastern Pawtuxet 

subbasins, the basinwide ratios for the gross yield and the 7Q10 

scenarios at the 50th and 25th percentiles were higher in 

August. The ratios for June, July, August, and September at the 

50th percentile for the 7Q10 scenario are illustrated for the subbasins in figure 19. 

In the Scituate Reservoir Complex subbasin, the estimated 

ground-water availability for the four summer months illustrates the probable pattern of ground-water fluctuations within 

the subbasin (table 23). The outlet of the Scituate Reservoir at 

the Gainer Dam is also the surface-water outlet for the subbasin. 

The regulated outflow of 83 Mgal/d from the reservoir was 

assumed to include the ground-water component of base flow 

(table 23) within the subbasins tributary to the reservoir. 

Because no additional water is discharged into the North 

Branch Pawtuxet River within the subbasin below the dam, 

there is no variation in the available water caused by flows 

downstream of the dam. Thus, the total available water is equal 

to the regulated outflow from the dam. (In addition, 9 Mgal/d 

are required to be released to the North Branch Pawtuxet River 

(Weston, 1990); thus, the gross yield for the Scituate Reservoir 

Complex subbasin was 92 Mgal/d.) Use that exceeds the safe 

yield during the summer months is offset by storage in the reservoir (table 25). This is the reason why the water used is most 

nearly equal to the available water (indicated by withdrawal-toavailability ratios closest to 1) in this subbasin. Because the 

total water available for each month was the same and the summer withdrawals (table 24) were lowest in September and highest in July (table 24), the ratios also were lowest in September 

and highest in July (table 25). 

For the gross yield scenario at the 50th percentile, the 

water availability for the North Branch Pawtuxet subbasin was 

lowest in August and highest in June; because summer water 

withdrawals were lowest in September and highest in August 

(table 24), however, the withdrawal-to-availability ratio was 

lowest in June and highest in August (table 25). For the gross 

yield scenario at the 50th percentile, the water-availability 

results for the South Branch Pawtuxet subbasin and Northeastern Pawtuxet subbasin were lowest in August and highest in 

June; however, summer water withdrawals were lowest in 

September and highest in July (table 24), and the ratios were 

lowest in June and highest in August (table 25). For the ABF 

scenario at the 50th and 25th percentiles, the North Branch, 

South Branch, and Northeastern Pawtuxet subbasins have no 

water available in August and September (table 23).

Quinebaug River Basin

In the Quinebaug River Basin, water availability in the 

subbasin for the gross yield at the 50th percentile was lowest in 

August and highest in June (table 26); however, summer water 

withdrawals were lowest in September and highest in July 

(table 27), and the withdrawal-to-availability ratios were lowest 

in June and highest in August (table 28). For the ABF scenario, 

the basin has no water available at the 50th percentile in August 

and September, and at the 25th percentile in July, August, and 

September (table 26). 

Water Budget

The water budget encompasses the hydrologic cycle and 

the water-use components, both of which produce inflows and 

outflows to the basin. In a basin water budget, inflow minus outflow equals the change in storage. For this investigation, calculation of the long-term water budget was based on the assumption that inflow equals outflow; the change in water storage 

from surface-water bodies and aquifers is considered to be negligible. Inflows to the basin include precipitation, streamflow 

from upstream subbasins, ground-water inflow, and return flow 

(from septic systems, RIPDES, and WWTFs). Outflows from 

the basin include evapotranspiration, streamflow out of the subbasins, water withdrawals (for public supply and self-supply 

domestic, commercial, industrial, and agricultural uses), and 

ground-water underflow. The water budget components are 

summarized in table 29 for the Pawtuxet River Basin and in 

table 30 for the Quinebaug River Basin. 

Pawtuxet River Basin 

Since 1917, ProvWater has collected precipitation data at 

a network of stations within the Scituate Reservoir Complex 

subbasin for management purposes, and these data were used to 

calculate the water budget for 1941 through 1999. The average 

precipitation for the Scituate Reservoir Complex subbasin 

(Providence Water Supply Board, written commun., 2000) 

(estimated to be 2.429 Mgal/d/mi2

) was used for the Scituate 

Reservoir Complex and North Branch Pawtuxet subbasin water 

budgets. The average precipitation at the Kingston climatological station (National Oceanic and Atmospheric Administration, 

2000) (estimated to be 2.280 Mgal/d/mi2

) was used for the 

South Branch Pawtuxet and the Northeastern Pawtuxet subba-
Water Budget 51

sin water budgets. The North Branch Pawtuxet and the Northeastern Pawtuxet subbasins have surface-water inflow from 

upstream subbasins. Data on ground-water inflow were not 

available for this study. Return flow includes the average rate of 

disposal from 1995 through 1999 from septic systems, RIPDES, and wastewater-treatment facilities. Evapotranspiration 

estimates were calculated as the difference between the mean 

annual precipitation per unit area and the mean annual flow per 

unit area at each subbasin’s assigned index station (table 29). 

The outflow of streamflow from each subbasin was estimated 

as sum of the inflows minus withdrawals minus

evapotranspiration. 

 The total water budget for the Pawtuxet River Basin was 

574.7 Mgal/d. The estimated inflows from precipitation and 

return flow were 94.7 and 5.3 percent of the total budget, and 

the estimated outflows from evapotranspiration, streamflow, 

and water withdrawals were 46.3, 40.8, and 12.9 percent, 

respectively. Forty percent of this water is accounted for in the 

Scituate Reservoir Complex subbasin. 

Quinebaug River Basin

The average precipitation for the Scituate Reservoir Complex (2.429 Mgal/d/mi2) (Providence Water Supply Board, 

written commun., 2000) was used to calculate the water budget 

for the Quinebaug River Basin for 1941 through 1999. Data for 

ground-water inflow were unavailable for this study. Return 

flow is the average rate of disposal from 1995 through 1999 

from septic systems. Evapotranspiration estimates were calculated as the difference between the mean annual precipitation 

per unit area and the mean annual flow per unit area at each subbasin’s assigned index station (table 30). The outflow from the 

basin was estimated as the sum of the inflows minus the withdrawals minus evapotranspiration.

The total water budget for the Quinebaug River Basin 

study area was 148.4 Mgal/d. The estimated inflows from precipitation and return flow were 99.8 and 0.2 percent of the total 

budget, respectively; and the estimated outflows from evapotranspiration, streamflow, and water withdrawals were 48.6, 

51.2, and 0.2 percent, respectively. 
52 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99 Table 23. Estimated ground-water availability and total availability for June, July, August, and September in the Pawtuxet River Basin, central Rhode Island, 1995–99.

[7Q10, 7-day, 10-year low flow; AB

F, Aquatic Base Flo

w; Mgal/d, million gallons per day; --, values at index station less than zero and not used]

Estimated gross yield for 7Q10 scenario Estimated gross yield for ABF scenario Estimated gross yield for June (Mgal/d) for June (Mgal/d) for June (Mgal/d)

Subbasin

75th 50th 25th 75th 50th 25th 75th 50th 25th

percentile percentile percentile percentile percentile percentile percentile percentile percentile

Scituate Reservoir Complex subbasin1 58.79 37.65 28.13 52.64 31.49 21.97 38.72 17.57 8.052

North Branch Pawtuxet subbasin1 8.521 5.456 4.077 7.629 4.564 3.185 5.611 2.546 1.167South Branch Pawtuxet subbasin2 94.23 66.43 55.43 86.40 58.79 47.79 67.20 40.05 29.05Northeastern Pawtuxet subbasin2 70.40 49.83 41.59 64.56 44.10 35.85 50.21 30.04 21.79

Total estimated gross yield 231.9 159.4 129.2 211.2 138.9 108.8 161.7 90.21 60.06

3 Total estimated available water 256.1 204.7 184.1 241.5 190.4 169.8 206.0 155.6 135.0

Estimated gross yield for 7Q10 scenario for Estimated gross yield for ABF scenario Estimated gross yield for July (Mgal/d) July (Mgal/d) for July (Mgal/d)

Subbasin

75th 50th 25th 75th 50th 25th 75th 50th 25th

percentile percentile percentile percentile percentile percentile percentile percentile percentile

Scituate Reservoir Complex subbasin1 27.84 21.28 19.09 21.68 15.13 7.762 7.758 1.208 --

North Branch Pawtuxet subbasin1 4.034 3.085 2.767 3.141 2.192 1.125 1.125 .175 --South Branch Pawtuxet subbasin2 44.51 33.21 24.70 36.68 25.57 17.06 17.47 6.828 --Northeastern Pawtuxet subbasin2 33.25 24.91 18.53 27.40 19.18 12.79 13.05 5.123 --

Total estimated gross yield 109.6 82.48 65.09 88.91 62.07 38.74 39.40 13.33 --

3 Total estimated available water 164.8 144.2 129.0 150.2 129.9 114.0 114.6 95.13 83.00
Water Budget 53

Table 23. Estimated ground-water availability and total availability for June, July, August, and September in the Pawtuxet River Basin, central Rhode Island, 1995–99.—Continued[7Q10, 7-day, 10-year low flow; ABF, Aquatic Base Flow; Mgal/d, million gallons per day; --, values at index station less than zero and not used]

Estimated gross yield for 7Q10 scenario Estimated gross yield for ABF scenario Estimated gross yield for August (Mgal/d) for August (Mgal/d) for August (Mgal/d)

Subbasin

75th 50th 25th 75th 50th 25th 75th 50th 25th

percentile percentile percentile percentile percentile percentile percentile percentile percentile

Scituate Reservoir Complex subbasin1 23.74 17.19 10.64 17.58 11.03 4.485 3.664 -- --

North Branch Pawtuxet subbasin1 3.441 2.492 1.543 2.548 1.599 .650 .531 -- --South Branch Pawtuxet subbasin2 42.76 23.41 16.60 34.93 15.78 8.963 15.72 -- --Northeastern Pawtuxet subbasin2 31.95 17.56 12.46 26.10 11.83 6.724 11.75 -- --

Total estimated gross yield 101.9 60.67 41.24 81.17 40.24 20.82 31.66 -- --

3 Total estimated available water 161.1 126.5 113.6 146.6 112.2 99.34 111.0 83.00 83.00

Estimated gross yield for 7Q10 scenario for Estimated gross yield for ABF scenario for Estimated gross yield for September (Mgal/d) September (Mgal/d) September (Mgal/d) Subbasin

75th 50th 25th 75th 50th 25th 75th 50th 25th

percentile percentile percentile percentile percentile percentile percentile percentile percentile

Scituate Reservoir Complex subbasin1 28.13 19.03 12.90 21.97 12.87 6.743 8.052 -- --

North Branch Pawtuxet subbasin1 4.077 2.758 1.870 3.185 1.866 .977 1.167 -- --South Branch Pawtuxet subbasin2 33.36 28.16 20.68 25.53 20.52 13.04 6.331 -- --Northeastern Pawtuxet subbasin2 24.93 21.12 15.51 19.08 15.39 9.778 4.730 -- --

Total estimated gross yield 90.50 71.08 50.96 69.77 50.65 30.54 20.28 -- --

3 Total estimated available water 145.4 135.0 121.1 130.8 120.8 106.8 95.23 83.00 83.00

1Estimated gross yield from ground water based on base flow from the Branch River at Forestdale, RI, stream-gaging station for the period 1957–99.2Estimated gross yield from ground water based on base flow from the Nooseneck River at Nooseneck, RI, stream-gaging station for the period 1964–80.3Total water-availability estimate for the Scituate Reservoir Complex subbasin is defined as the net safe yield of 83 Mgal/d instead of the estimated gross yield. 
54 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

PAWTUXET BASIN

QUINEBAUG BASIN

JUNE

JULY

AUGUST

SEPTEMBER

 NORTH BRANCH

PAWTUXET

 SOUTH BRANCH

PAWTUXET

 NORTHEASTERN

PAWTUXET

 QUINEBAUG

BASIN

WATER AVAILABILITY, IN MILLION

GALLONS PER DAY

WATER AVAILABILITY, IN MILLION

GALLONS PER DAY

WATER AVAILABILITY, IN MILLION

GALLONS PER DAY

C. AVAILABILITY AT THE 50th PERCENTILE FOR THE AQUATIC BASE FLOW SCENARIO

B. AVAILABILITY AT THE 50th PERCENTILE FOR THE 7-DAY, 10-YEAR LOW-FLOW SCENARIO

A. AVAILABILITY AT THE 50th PERCENTILE

EXPLANATION

0

5

10

15

20

25

30

35

40

45

50

0

5

10

15

20

25

30

35

40

45

50

0

5

10

15

20

25

30

35

40

45

50

SCITUATE

RESERVOIR

COMPLEX

 NORTH BRANCH

PAWTUXET

 SOUTH BRANCH

PAWTUXET

 NORTHEASTERN

PAWTUXET

 QUINEBAUG

BASIN

SCITUATE

RESERVOIR

COMPLEX

 NORTH BRANCH

PAWTUXET

 SOUTH BRANCH

PAWTUXET

 NORTHEASTERN

PAWTUXET

 QUINEBAUG

BASIN

SCITUATE

RESERVOIR

COMPLEX

Figure 17. Estimated water availability for June, July, August, and September from sand and gravel deposits for 

the subbasins in the Pawtuxet and Quinebaug River Basins, central and western Rhode Island, for the A, 50th percentile; 

B, 50th percentile for the 7-day, 10-year low-flow scenario; and C, 50th percentile for the Aquatic Base Flow scenario.
Water Budget 55

0

5

10

15

20

25

0

5

10

15

20

25

WATER AVAILABILITY, IN MILLION

GALLONS PER DAY

WATER AVAILABILITY, IN MILLION

GALLONS PER DAY

WATER AVAILABILITY, IN MILLION

GALLONS PER DAY

0

5

10

15

20

25

A. AVAILABILITY AT THE 50th PERCENTILE

B. AVAILABILITY AT THE 50th PERCENTILE FOR THE 7-DAY, 10-YEAR LOW-FLOW SCENARIO

C. AVAILABILITY AT THE 50th PERCENTILE FOR THE AQUATIC BASE FLOW SCENARIO

PAWTUXET BASIN

QUINEBAUG BASIN

JUNE

JULY

AUGUST

SEPTEMBER

EXPLANATION

 NORTH BRANCH

PAWTUXET

 SOUTH BRANCH

PAWTUXET

 NORTHEASTERN

PAWTUXET

 QUINEBAUG

BASIN

SCITUATE

RESERVOIR

COMPLEX

 NORTH BRANCH

PAWTUXET

 SOUTH BRANCH

PAWTUXET

 NORTHEASTERN

PAWTUXET

 QUINEBAUG

BASIN

SCITUATE

RESERVOIR

COMPLEX

 NORTH BRANCH

PAWTUXET

 SOUTH BRANCH

PAWTUXET

 NORTHEASTERN

PAWTUXET

 QUINEBAUG

BASIN

SCITUATE

RESERVOIR

COMPLEX

Figure 18. Estimated water availability for June, July, August, and September from till deposits for the 

subbasins in the Pawtuxet and Quinebaug River Basins, central and western Rhode Island, for the A, 50th percentile; 

B, 50th percentile for the 7-day, 10-year low-flow scenario; and C, 50th percentile for the Aquatic Base Flow scenario.
56 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99 Table 24. Average water withdra

wals for June, July, August, and September in the subbasins of the Pawtuxet River Basin, central Rhode Island, 1995–99.

[Mgal/d, million gallons per day; --, not applicable]

Total average water withdrawals Average water withdrawals 1995–99 (Mgal/d) 1995–99 (Mgal/d)

Subbasin June July

August September June July

August September Public Self Public Self Public Self Public Self

Scituate Reservoir Complex subbasin 88.06 1.010 96.12 1.055 87.45 1.022 75.66 0.990 89.07 97.18 88.47 76.65North Branch Pawtuxet subbasin -- .215 -- .227 -- .250 -- .130 .25 .227 .250 .130South Branch Pawtuxet subbasin 1.187 .829 1.251 .835 1.195 .811 1.163 .700 2.016 2.086 2.006 1.863Northeastern Pawtuxet subbasin -- .698 -- .703 -- .691 -- .415 .698 .703 .691 .415

Basin total 89.25 2.752 97.37 2.820 88.65 2.774 76.82 2.235 92.00 100.20 91.42 79.06

Table 25. Summary of water withdrawal-to-availability ratios for June, July, August, and September in the Pawtuxet River Basin, central Rhode Island, 1995–99.[7Q10, 7-day, 10-year low flow; AB

F, Aquatic Base Flo

w; Mgal/d, million gallons per day; --, values at index station less than zero and not used]

Ratio for June, estimated Ratio for June, estimated Ratio for June, estimated gross yield gross yield for 7Q10 scenario gross yield for ABF scenario Subbasin

75th 50th 25th 75th 50th 25th 75th 50th 25th

percentile percentile percentile percentile percentile percentile percentile percentile percentile

Scituate Reservoir Complex subbasin1 1.073 1.073 1.073 1.073 1.073 1.073 1.073 1.073 1.073

North Branch Pawtuxet subbasin2 .025 .039 .053 .028 .047 .068 .038 .084 .184South Branch Pawtuxet subbasin3 .021 .030 .036 .023 .034 .042 .030 .050 .069Northeastern Pawtuxet subbasin3 .010 .014 .017 .011 .016 .019 .014 .023 .032

Basin ratio 0.359 0.449 0.500 0.381 0.483 0.542 0.447 0.591 0.681

Ratio for July, estimated Ratio for July, estimated Ratio for July, estimated gross yield scenario gross yield for 7Q10 scenario gross yield for ABF scenario Subbasin

75th 50th 25th 75th 50th 25th 75th 50th 25th

percentile percentile percentile percentile percentile percentile percentile percentile percentile

Scituate Reservoir Complex subbasin1 1.171 1.171 1.171 1.171 1.171 1.171 1.171 1.171 1.171

North Branch Pawtuxet subbasin2 .056 .074 .082 .072 .104 .202 .202 1.297 --South Branch Pawtuxet subbasin3 .047 .063 .084 .057 .082 .122 .122 .306 --Northeastern Pawtuxet subbasin3 .021 .028 .038 .026 .037 .055 .055 .137 --

Basin ratio 0.608 0.695 0.777 0.667 0.771 0.879 0.874 1.053 1.207
Water Budget 57

Table 25. Summary of water withdrawal-to-availability ratios for June, July, August, and September in the Pawtuxet River Basin, central Rhode Island, 1995–99.—Continued[7Q10, 7-day, 10-year low flow; ABF, Aquatic Base Flow; Mgal/d, million gallons per day; --, values at index station less than zero and not used]

Ratio for August, estimated Ratio for August, estimated Ratio for August, estimated gross yield gross yield for 7Q10 scenario gross yield for ABF scenario Subbasin

75th 50th 25th 75th 50th 25th 75th 50th 25th

percentile percentile percentile percentile percentile percentile percentile percentile percentile

Scituate Reservoir Complex subbasin1 1.066 1.066 1.066 1.066 1.066 1.066 1.066 1.066 1.066

North Branch Pawtuxet subbasin2 .073 .100 .162 .098 .156 .385 .471 -- --South Branch Pawtuxet subbasin3 .047 .086 .121 .057 .127 .224 .128 -- --Northeastern Pawtuxet subbasin3 .022 .039 .055 .026 .058 .103 .059 -- --

Basin ratio 0.567 0.723 0.805 0.624 0.815 0.920 0.824 1.101 1.101

Ratio for September, estimated Ratio for September, estimated Ratio for September, estimated gross yield gross yield for 7Q10 scenario gross yield for ABF scenario Subbasin

75th 50th 25th 75th 50th 25th 75th 50th 25th

percentile percentile percentile percentile percentile percentile percentile percentile percentile

Scituate Reservoir Complex subbasin1 0.923 0.923 0.923 0.923 0.923 0.923 0.923 0.923 0.923

North Branch Pawtuxet subbasin2 .032 .047 .070 .041 .070 .133 .111 -- --South Branch Pawtuxet subbasin3 .056 .066 .090 .073 .091 .143 .294 -- --Northeastern Pawtuxet subbasin3 .017 .020 .027 .022 .027 .042 .088 -- --

Basin ratio 0.544 0.585 0.653 0.604 0.655 0.740 0.830 0.953 0.953

1Water-availability estimate is based on the Scituate Reservoir net safe yield of 83 Mgal/d (Weston, 1990).2Estimated gross yield based on base flow from the Branch River at Forestdale, RI, stream-gaging station for the period 1957–99.3Estimated gross yield based on base flow from the Nooseneck River at Nooseneck, RI, stream-gaging station for the period 1964–80.
58 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99 MASSACHUSETTS CONNECTICUT RHODE ISLAND

MASSACHUSETTS

MASSACHUSETTS

CONNECTICUT

RHODE ISLAND

MASSACHUSETTS

MASSACHUSETTS

CONNECTICUT

RHODE ISLAND

MASSACHUSETTS

MASSACHUSETTS

CONNECTICUT

RHODE ISLAND

MASSACHUSETTS

41o

45'

42o

00'

41o

45'

42o

00'

41o

45'

42o

00'

71o

45' 71o30'

41o

45'

42o

00'

71o

45' 71o30'

71o

45' 71o30' 71o45' 71o30'

0 5 KILOMETERS

Base from U.S. Geological Survey and Rhode Island Geographic Information 0 5 MILES

System digital data, 1:24,000, Lambert conformal conic projection, 

1983 North American datum

1.073

0.016

0.047

0.034

0.018

1.171

0.037

0.104

0.082

0.038

1.066

0.058

0.156

0.127

0.048

0.923

0.027

0.070

0.091

0.032

A. B.

C. D.

SCITUATE RESERVOIR 

COMPLEX

NORTHEASTERN 

PAWTUXET 

NORTH

BRANCH

PAWTUXET

SOUTH BRANCH

PAWTUXET

SCITUATE RESERVOIR 

COMPLEX

NORTHEASTERN 

PAWTUXET 

NORTH

BRANCH

PAWTUXET

SOUTH BRANCH

PAWTUXET

SCITUATE RESERVOIR 

COMPLEX

NORTHEASTERN 

PAWTUXET 

NORTH

BRANCH

PAWTUXET

SOUTH BRANCH

PAWTUXET

SCITUATE RESERVOIR 

COMPLEX

NORTHEASTERN 

PAWTUXET 

NORTH

BRANCH

PAWTUXET

SOUTH BRANCH

PAWTUXET

QUINEBAUG

RIVER

BASIN

QUINEBAUG

RIVER

BASIN

QUINEBAUG

RIVER

BASIN

QUINEBAUG

RIVER

BASIN

JUNE WITHDRAWAL-TO-AVAILABILITY RATIOS JULY WITHDRAWAL-TO-AVAILABILITY RATIOS

 AUGUST WITHDRAWAL-TO-AVAILABILITY RATIOS SEPTEMBER WITHDRAWAL-TO-AVAILABILITY RATIOS

Figure 19. The water withdrawal-to-availability ratios in A, June; B, July; C, August; and D, September for the subbasins in the 

Pawtuxet and Quinebaug River Basins, central and western Rhode Island, at the 50th percentile for the 7-day, 10-year low-flow scenario.
Water Budget 59

Table 26. Estimated gross yield; gross yield for the 7-day, 10-year low-flow scenario; and gross yield for the Aquatic Base Flow 

scenario for June, July, August, and September in the Quinebaug River Basin, western Rhode Island.

[Estimated gross yields calculated from base flow at the Branch River at Forestdale, RI, stream-gaging station, 1957–99. 7Q10, 7-day, 10-year low flow; 

ABF, Aquatic Base Flow; Mgal/d, million gallons per day; --, values at index station less than zero and not used]

Estimated gross yield for the 7Q10 Estimated gross yield for the ABF Estimated gross yield (Mgal/d) scenario (Mgal/d) scenario (Mgal/d) Month

75th 50th 25th 75th 50th 25th 75th 50th 25th

percentile percentile percentile percentile percentile percentile percentile percentile percentile

Estimated yields from sand and gravel deposits

June 27.50 17.61 13.16 24.62 14.73 10.28 18.11 8.216 3.765

July 13.02 9.954 8.930 10.14 7.074 3.630 3.628 .565 --

August 11.10 8.040 4.978 8.223 5.160 2.097 1.714 -- --

September 13.156 8.901 6.033 10.28 6.021 3.153 3.765 -- --

Estimated yields from till deposits

June 20.18 12.92 9.656 18.07 10.81 7.542 13.29 6.031 2.764

July 9.555 7.306 6.554 7.441 5.192 2.664 2.663 .415 --

August 8.150 5.901 3.654 6.036 3.787 1.539 1.258 -- --

September 9.656 6.533 4.428 7.542 4.419 2.314 2.764 -- --

Total estimated yields

June 47.68 30.53 22.81 42.69 25.54 17.82 31.40 14.25 6.529

July 22.57 17.26 15.49 17.58 12.27 6.295 6.291 .980 --

August 19.25 13.94 8.632 14.26 8.947 3.637 2.971 -- --

September 22.81 15.43 10.46 17.82 10.44 5.468 6.529 -- --

Table 27. Average water withdrawals for June, July, August, and 

September in the towns in the Quinebaug River Basin, 

western Rhode Island, 1995–99.

[Mgal/d, million gallons per day]

Average water withdrawals 1995–99 (Mgal/d) Town

June July August September

Burrillville 0.037 0.037 0.037 0.036

Coventry .147 .153 .124 .120

Exeter .006 .006 .006 .006

Foster .216 .216 .211 .120

Glocester .052 .048 .051 .048

West Greenwich .003 .003 .003 .003

Basin total 0.461 0.463 0.432 0.333
60 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

Table 28. Summary of water withdrawal-to-availability ratios for June, July, August, and September in the Quinebaug River Basin, 

western Rhode Island, 1995–99.

[Estimated gross yields calculated from base flow at the Branch River at Forestdale, RI, stream-gaging station for 1957–99. 7Q10, 7-day, 10-year low flow; 

ABF, Aquatic Base Flow; Mgal/d, million gallons per day; --, values at index station less than zero and not used]

Ratio for the estimated gross Ratio for the estimated gross Ratio for the estimated gross yield yield for the 7Q10 scenario yield for the ABF scenario

Month

75th 50th 25th 75th 50th 25th 75th 50th 25th

percentile percentile percentile percentile percentile percentile percentile percentile percentile

June 0.010 0.015 0.020 0.011 0.018 0.026 0.015 0.032 0.071

July .021 .027 .030 .026 .038 .074 .074 .472 --

August .022 .031 .050 .030 .048 .145 .145 -- --

September .015 .022 .032 .019 .032 .051 .051 -- --

Table 29. Average water budget by subbasin for the Pawtuxet River Basin, central Rhode Island.

[Shaded areas are basin totals. RIPDES, Rhode Island Pollutant Discharge Elimination System; in/yr, inches per year; Mgal/d, million gallons per day; 

Mgal/d/mi2

, million gallons per day per square mile; mi2, square mile; --, not applicable]

North Branch South Branch Northeastern Scituate Reservoir Pawtuxet River Water-budget component Pawtuxet Pawtuxet Pawtuxet Complex subbasin Basin total subbasin subbasin subbasin

Estimated inflow (Mgal/d)

Precipitation 1

228.6 134.22 2165.7 2115.6 544.1

Streamflow from upstream subbasins -- 36.33 -- 154.6 --

Ground-water inflow -- -- -- -- --

Return flow3 .887 1.094 6.210 22.45 30.64

Total inflow 229.5 71.64 171.9 292.6 574.7

Estimated outflow (Mgal/d)

Evapotranspiration4 5121.3 518.16 668.83 757.81 266.1

Streamflow8 36.33 53.34 101.3 234.5 234.5

Wa 9 ter withdrawals 71.87 .138 1.747 .306 74.06

Ground-water underflow -- -- -- -- --

Total outflow 229.5 71.64 171.9 292.6 574.7

Streamflow at confluence per square mile 0.386 0.493 1.394 1.012 1.012

(Mgal/d/mi2)

Total drainage area at outlet (mi2)

10 94.11 108.2 72.68 231.6 231.6

1

Based on average precipitation (51.00 in/yr (equal to 2.429 Mgal/d/mi

2

)) in the Scituate Reservoir Complex subbasin for the period 1941–99 (data from 

precipitation network, Providence Water Supply Board, written commun., 2000).

2Based on average precipitation (47.87 in/yr (equal to 2.280 Mgal/d/mi2)) at Kingston, RI for the period 1941–99 (data from National Oceanic and 

Atmospheric Administration, 2000).

3

Based on the total return flow from septic, RIPDES, and wastewater-treatment facilities in the subbasins of the Pawtuxet River Basin, 1995–99. 

4

Evapotranspiration based on the difference between the average precipitation and average monthly flow at the index stream-gaging station for the subbasin.

5

Based on the difference between the average annual precipitation per unit area (2.429 Mgal/d/mi2; data from Providence Water Supply Board, written 

commun., 2000) and average annual flow per unit area (1.140 Mgal/d/mi2

) at the stream-gaging station Pawtuxet River at Cranston, RI for the period 1941–99.

6

Based on the difference between the average annual precipitation per unit area measured at the Kingston climatological station (2.280 Mgal/d/mi

2

; data from 

National Oceanic and Atmospheric Administration, 2000) and average annual flow per unit area (1.333 Mgal/d/mi2) at the stream-gaging station South Branch 

Pawtuxet River at Washington, RI for the period 1941–99. 

7

Based on the difference between the average annual precipitation per unit area measured at the Kingston climatological station (2.280 Mgal/d/mi

2; data from 

National Oceanic and Atmospheric Administration, 2000) and average annual flow per unit area (1.140 Mgal/d/mi2

) at the stream-gaging station Pawtuxet River

at Cranston, RI for the period 1941–99.

8Based on the sum of the inflows minus the sum of the withdrawals minus evapotranspiration.

9Water-withdrawal types include domestic, commercial, industrial, and agricultural from public and self-supply in the subbasins of the Pawtuxet River Basin,

1995–99.

10Based on the sum of the subbasin drainage area and drainage areas upstream of the subbasin. 
Summary 61

Summary

During a drought in 1999, ground-water levels and streamflows dropped below long-term averages throughout Rhode 

Island. Consequently, the State of Rhode Island became concerned about water availability, and further investigation was 

needed to assess water use and availability throughout the state. 

The U.S. Geological Survey (USGS), in cooperation with the 

Rhode Island Water Resources Board (RIWRB), began a series 

of water-use and availability investigations for 1995–99 to 

describe the relations between water-use and hydrologic-cycle 

components for both surface and ground water during periods 

of little to no recharge. The investigations for the Pawtuxet 

(area 231.6 mi2) and Quinebaug (area 60.97 mi2

) River Basins 

are two of a planned series of nine being completed for basins 

in Rhode Island. 

In addition to water use and availability, basin water budgets were calculated to summarize the components of the 

hydrologic cycle and selected water-use components for 1941 

through 1999. Data were collected for the subbasins in this 

study by using the spatial delineation derived from the surfacewater-system drainage areas. The New England Water-Use 

Data System was used to organize and retrieve data for water 

withdrawals, users by category, and return flows for the study 

period. 

In the Pawtuxet River Basin, the Scituate Reservoir was 

the primary source of water withdrawn by public suppliers 

(about 95 percent of the average annual water withdrawals during the study period). The only major public water supplier in 

the Scituate Reservoir Complex subbasin is Providence Water 

Supply Board, which supplies almost all of the other basins in 

Rhode Island, including the Blackstone, the Moshassuck, the 

Woonasquatucket, the Narragansett Bay, and the Westport 

Basins. Only the Quinebaug, the Pawcatuck, and the South 

Coastal Basins are not supplied by the Scituate Reservoir. In the 

Quinebaug River Basin, ground water is the sole source for the 

one minor public supplier and all the domestic users, which 

together accounted for about 89 percent of the average annual 

water withdrawals during the study period. 

In the Pawtuxet River Basin, two major water suppliers 

withdrew a total of 71.86 Mgal/d from ground and surface water 

(which includes the Scituate Reservoir). Estimated water withdrawals from minor water suppliers were 0.026 Mgal/d in the 

Pawtuxet River Basin and 0.003 Mgal/d in the Quinebaug River 

Basin. About 35.98 Mgal/d of potable water from major publicsupply withdrawals was exported from the Pawtuxet River 

Basin to other basins in Rhode Island. Self-supply domestic, 

industrial, commercial, and agricultural withdrawals from the 

basin totaled 2.173 Mgal/d in the Pawtuxet River Basin and 

0.360 Mgal/d in the Quinebaug River Basin. Total water use 

was 18.07 Mgal/d in the Pawtuxet River Basin and was 0.363 

Mgal/d in the Quinebaug River Basin. The total return flow was 

30.64 Mgal/d in the Pawtuxet River Basin, which included 

effluent from permitted facilities and water users on self-disposal; of the total, about 12.28 Mgal/d of wastewater was 

imported to the Pawtuxet River Basin from other basins in 

Rhode Island. Return flow in the Quinebaug River Basin was 

0.283 Mgal/d. 

Ground-water availability was estimated from output from 

the PART program, a computerized hydrograph-separation 

application. To determine water availability at the 75th, 50th, 

and 25th percentiles, two index stream-gaging stations in 

nearby basins were used for three scenarios: the total base-flow 

scenario; the base flow for the 7-day, 10-year (7Q10) low-flow 

scenario; and the base flow for the Aquatic Base Flow (ABF) 

scenario. A regression equation was used to estimate unknown 

base-flow contributions from sand and gravel deposits at the 

two stations. The water available at the Branch River at Forestdale, Rhode Island, stream-gaging station was lowest in August 

Table 30. Average water budget for the Quinebaug River Basin, 

western Rhode Island.

[Shaded areas are basin totals. in/yr, inches per year; Mgal/d, million gallons 

per day; Mgal/d/mi2, million gallons per day per square mile; mi2, square

miles; --, not applicable]

Water-budget component Quinebaug

River Basin total

Estimated inflow (Mgal/d)

Precipitation1 148.1

Streamflow from upstream subbasins --

Ground-water inflow --

Return flow2 .283

Total inflow 148.4

Estimated outflow (Mgal/d)

Evapotranspiration3 72.07

Streamflow4 75.97

Wa 5 ter withdrawals .363

Ground-water underflow --

Total outflow 148.4

Streamflow per square mile (Mgal/d/mi

2

) 1.246

Total drainage area at outlet (mi2)

6 60.97

1

Based on average precipitation (51.00 in/yr) in the Scituate Reservoir Com

plex subbasin for the period 1941–99 (data from precipitation network, Providence Water Supply Board, written commun., 2000).

2Based on the total return flow from septic in the Quinebaug River Basin,

1995–99.

3

Evapotranspiration is based on the difference between the average annual 

precipitation per unit area (2.429 Mgal/d/mi2; data from precipitation network,

Providence Water Supply Board, written commun., 2000) and average annual

flow per unit area (1.247 Mgal/d/mi2) at the stream-gaging station Branch Riv

er at Forestdale, RI, for the period 1941–99.

4Based on the sum of the inflows minus the sum of the withdrawals minus 

evapotranspiration.

5Water-withdrawal types include domestic, commercial, industrial, and agri

cultural from public and self-supply in the Quinebaug River Basin,

1995–99.

6

Basin outlet is defined as the political boundary with Connecticut for this 

study.

-

-

-
62 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

at the 75th, 50th, and 25th percentiles (29.67, 21.48, and 

13.30 Mgal/d, respectively). The water available at the Nooseneck River at Nooseneck, Rhode Island, stream-gaging station 

was lowest in September at the 75th percentile (3.551 Mgal/d) 

and in August at the 50th and 25th percentiles (2.554 and 

1.811 Mgal/d). 

Base-flow contributions at the stations estimated from 

sand and gravel deposits and from till deposits (surficial deposits) were divided by the respective drainage areas for the two 

types of deposits to give ratios of flow per unit area. The ratios 

were multiplied by the areas of the sand and gravel deposits and 

till deposits in the subbasins. Finally, the total flows from the 

sand and gravel deposits and till deposits in the subbasin were 

added to obtain the gross yield. In the Pawtuxet River Basin, the 

gross yield from ground water was assumed to be part of the net 

safe yield of 83 Mgal/d from the Scituate Reservoir. This 

amount was defined as the total water available for the Scituate 

Reservoir Complex subbasin.

Because water withdrawals and use are greater during the 

summer than other times of the year, water availability at the 

75th, 50th, and 25th percentiles in June, July, August, and September was calculated and compared to water withdrawals in 

the basin and subbasins. The closer the withdrawals are to the 

estimated water available because the net water available 

decreases, the closer the resulting ratio is to one. For the study 

period, withdrawals in July were higher than withdrawals in the 

other summer months in both basins. For the Pawtuxet River 

Basin, the ratios were higher in August than in the other three 

summer months for all three scenarios at the 50th percentile. 

The ratios were close to 1 for the Scituate Reservoir Complex 

subbasin for all scenarios in all of the summer months because 

of the fixed safe yield from the Scituate Reservoir. For the 

Quinebaug River Basin, the ratios were also higher in August 

for all three scenarios, but because of reduced water availability, were generally lower than the total basin ratios for the Pawtuxet River Basin. 

For estimating the water budget, it was assumed that 

inflow equals outflow. The water budgets of the Pawtuxet River 

Basin and the Rhode Island part of the Quinebaug River Basin 

were 574.9 Mgal/d and 148.4 Mgal/d, respectively. The estimated inflows from precipitation and return flow were 94.7 and 

5.3 percent, respectively, of the total budget for the Pawtuxet 

River Basin. The estimated inflow from precipitation was 99.8 

percent of the total budget for the Quinebaug River Basin. The 

estimated outflows in the Pawtuxet River Basin from evapotranspiration, streamflow, and water withdrawals were 46.3, 

40.8, and 12.9 percent of the budget, respectively. The estimated outflows in the Quinebaug River Basin from evapotranspiration and streamflow were 48.6 and 51.2 percent of the budget, respectively.

Acknowledgments

Original water-use withdrawal and discharge data were 

collected from the public-supply districts, the RIDEM Office of 

Water Resources, individual wastewater-discharge facilities, 

and the Rhode Island Water Resources Board. The authors 

thank the following individuals for assisting in the data-collection process: George Corrente, Johnston Water District; Timothy Brown, Kent County Water Authority; Richard Blodgett 

and Peter LePage, Providence Water Supply Board; Daniel 

O’Rourke and Robert Desaulniers, Warwick Water Department; Christian Bratina, Cranston Water Pollution Control 

Facility; Carmine Goneconte, Narragansett Bay Commission—Fields Point; Joel Burke, Warwick Wastewater Facility; 

Michael Roberts, West Warwick Wastewater Facility; Aaron 

Mello, RIDEM Office of Water Resources; Clay Commons, 

Rhode Island Department of Health, Office of Drinking Water 

Quality; Amanda Aretz, Andrew Thorpe, and Carol Gannon, 

formerly of the U.S. Geological Survey; and Dennis Ventetuolo 

and Tomas Smieszek, U.S. Geological Survey. 

Selected References

Allen, W.B., 1953, The ground-water resources of Rhode 

Island, with a section on Surface-water resources, by H.B. 

Kinnison: Rhode Island Water Resources Board Geological 

Bulletin 6, 170 p. 

Allen, W.B., 1956, Ground-water resources of the East Greenwich quadrangle, Rhode Island: Rhode Island Water 

Resources Board Geological Bulletin 8, 56 p., 3 pl., scale 

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Glossary 67

Glossary

7-day, 10-year low flow (7Q10) The discharge at the 10-year 

recurrence interval taken from a frequency curve of annual 

values of the lowest mean discharge for 7 consecutive days (the 

7-day low flow). 

Aquatic Base Flow (ABF) As established by the U.S. Fish and 

Wildlife Service, median flow during the month of August 

considered adequate to protect indigenous aquatic fauna 

throughout the year. It can be calculated as long as there are 

USGS stream-gaging data for at least 25 years of unregulated 

flow, and the drainage area at the stream-gaging station is at 

least 50 square miles (U.S. Fish and Wildlife, 1981).

Base flow Streamflow from ground-water discharge.

Commercial water use Water used for transportation; 

wholesale trade; retail trade; finance, insurance, and real estate; 

services; and public administration (the two-digit Standard 

Industrial Classification codes are in the range 40-97). The 

water can be from public or self-supply. 

Consumptive use Water that is removed from the 

environment through evaporation, transpiration, production, or 

consumed by humans or livestock.

Conveyance Movement of water from one point to another, 

for example, water withdrawals, water distributions, and 

wastewater collection.

Distribution The conveyance of water from a point of 

withdrawal or purification system to a user or other water 

customer.

Domestic water use Water used for household purposes, 

such as drinking, food preparation, bathing, washing, clothes 

and dishes, flushing toilets, and watering lawns and gardens. 

Households include single and multifamily dwellings. Also 

called residential water use. The water may be obtained from a 

public water supply or may be self-supplied.

Industrial water use Water used for food; tobacco; textile 

mill products; apparel; lumber and wood; furniture; paper; 

printing; chemicals; petroleum; rubber; leather; stone, clay, 

glass, and concrete; primary metal; fabricated metal; 

machinery; electrical equipment; transportation equipment; 

instruments; and jewelry, precious metals; for which the twodigit Standard Industrial Classification code range is 20-39. 

The water may be obtained from a public water supply or may 

be self-supplied. 

Interbasin transfers Conveyance of water across a drainage 

or river-basin divide.

Interconnections Links between public-supply districts to 

convey water. These connections can be for wholesale 

distributions or water-supply backups. 

Irrigation water use The application of water to lands to 

assist in the growth of crops or pasture, including plants in 

greenhouses. Irrigation water use may also include application 

of water to maintain vegetative growth on recreational lands 

such as parks and golf courses and to provide frost and freeze 

protection of crops.

Major water supplier A public or private system that 

withdraws and distributes water to customers or other suppliers 

for use.

Major user In Rhode Island, a customer that uses more than 

three million gallons of water per year.

Minor Civil Division (MCD) A term used by the U.S. Census 

Bureau, generally equivalent to a city or town.

Minor public water suppliers Water withdrawn to supply a 

site-specific public population, for example nursing homes, 

condominium complexes, and mobile home parks. 

Nonaccount water use The difference between the metered 

(or reported) supply and the metered (or reported) use for a 

specific period of time, which includes water used for fire 

fighting. It comprises authorized and unauthorized water uses. 

Outfall The outlet or structure through which effluent is 

finally discharged into the environment.

Per capita water use The average volume of water used per 

person during a standard time period, generally per day. 

PART A computer program developed by A.T. Rutledge 

(1993 and 1998) to determine the mean rate of ground-water 

discharge.

Public wastewater system Wastewater collected from users 

or groups of users, conveyed to a wastewater-treatment plant, 

and then released as return flow into the hydrologic 

environment or sent back to users as reclaimed wastewater.

Public water system Water withdrawn by public and private 

water systems, and then delivered to users or groups of users. 

Public water systems provide water for a variety of uses, such 

as domestic, commercial, industrial, agricultural, and public 

water use.

Public water use Water supplied from a public water system 

and used for fire fighting, street washing, and municipal parks 

and swimming pools.

Public-disposed water Wastewater return flow from public 

and private wastewater-collection systems.

Public-supply water Water distributed to domestic, 

industrial, commercial, agricultural or other customers by a 

public or private water-supply system.

Return flow Water that is returned to surface or ground water 

after use or wastewater treatment, and thus becomes available 

for reuse. Return flow can go directly to surface water, directly 

to ground water through an injection well or infiltration bed, or 

indirectly to ground water through a septic system. 

Self-disposed water Water returned to the ground (septic 

systems) by a user or group of users that are not on a 

wastewater-collection system. 

Self-supply water Water withdrawn from a ground- or 

surface-water source by a user and not obtained from a public 

or private water-supply system.
68 Estimated Water Use and Availability in the Pawtuxet and Quinebaug River Basins, Rhode Island, 1995-99

Standard Industrial Classification (SIC) code Four-digit 

codes established by the U.S. Office of Management and 

Budget and used in the classification of establishments by type 

of activity in which they are engaged. The IWR-MAIN 

coefficients for industrial and commercial water use are based 

on the first two digits.

Surface-water return flow Effluent that flows from a 

discharge pipe to a river or lake.

Wastewater Water that carries wastes from domestic, 

industrial, and commercial consumers; a mixture of water and 

dissolved or suspended solids.

Wastewater treatment The processing of wastewater for the 

removal or reduction of contained solids or other undesirable 

constituents.

Wastewater-treatment return flow Water returned to the 

hydrologic system by wastewater-treatment facilities. Also 

referred to as effluent water.

Water purification The processes that withdrawn water may 

undergo prior to use, including chlorination, fluoridation, and 

filtration.

Water supply All of the processes that are involved in 

obtaining water for the user before use. Includes withdrawal, 

water treatment, and other distribution.

Water use (1) In a restrictive sense, the term refers to water 

that is actually used for a specific purpose, such as for domestic 

use, irrigation, or industrial processing. (2) More broadly, 

water use pertains to human interaction with and impact on the 

hydrologic cycle, and includes elements such as water 

withdrawal, distribution, consumptive use, wastewater 

collection, and return flow.

Withdrawal The removal of surface water or ground water 

from the natural hydrologic system for uses such as public 

water supply, industry, commerce, domestic use, irrigation, 

livestock, and thermoelectric power generation.