2. Supplement to Report: Commute Sheds as a Regional Water Management Decision Tool This is a working file, subject to updates. For individual use only. Please contact author prior to redistribution or citation. benjamin.landis@duke.edu ©2009

3. Commute Sheds as an Integrated Watershed Management Decision Tool Benjamin Young Landis Nicholas School of the Environment Duke University

4. BACKGROUND: OnTheMap is a new software that analyzes commute sheds – a type of regional resource analysis QUESTION: Does commute shed analysis have applications in regional water supply decision making? CASE STUDY: Upper Neuse River Basin, NC Abstract

5. Raleigh Wake Forest, Rolesville, Knightdale, Wendell, Zebulon, Garner Raleigh Wake Forest, Rolesville, Knightdale, Wendell, Zebulon, Garner Hillsborough South Granville Butner, Stem, Creedmoor South Granville Butner, Stem, Creedmoor Durham Upper Neuse River Basin Upper Neuse River Basin Falls Lake Chapel Hill (Cape Fear Basin) Chapel Hill, Carrboro Chapel Hill (Cape Fear Basin) Chapel Hill, Carrboro Jordan Lake (Cape Fear Basin) Cary, Morrisville, Apex Jordan Lake (Cape Fear Basin) Cary, Morrisville, Apex Jordan Lake Kerr Lake (Roanoke Basin) Oxford, Henderson, South Henderson Kerr Lake (Roanoke Basin) Oxford, Henderson, South Henderson

6. Water supply is no longer just a function of individual communities. Clearly, it's a regional issue. -- Sydney Paul Miller Water Resources Program Manager Triangle J Council of Governments (Will the Water Run Out? Town Hall, 08 January 2008)

7. Disparate Supply: Some cities have adequate water supplies and facilities. Some do not. Cities are moving towards regional sharing and optimization of water supplies Need new tools to inform water sharing decisions and trace flows of water benefits Can commute sheds offer a new perspective? Water Supply Around the Upper Neuse

8. Watershed: – The flow of water from sources to receiving sink Commute shed: – The flow of commuters from home city to city of employment Analyzed by tourism and labor economists Used by city planners to attract development and site public services Commute Sheds and OnTheMap

9. OnTheMap version 3 – U.S. Census Bureau, 2008 Determines: – Number of workers in a home city – Number of workers that commute – To which other cities these workers commute Analyze by subgroups (e.g. by earnings) Commute Sheds and OnTheMap

11. Recall: Cities are moving towards regional sharing and optimization of water supplies Cities would physically connect and benefit from each others water supply But, are cities already virtually connected and benefiting from each others water supply? Applying Commute Sheds to Regional Water Supplies

12. A city invests in water supply and infrastructure to help sustain its residents Residents work, and generate economic impact Thus: – Water supply helps generate economic impact – Economic impact is a benefit of water supply Applying Commute Sheds to Regional Water Supplies

13. When residents commute to a different city to work, they export their economic impact These commuters also export the benefits of their home citys water supply Commute sheds represent the exports of water supply benefits amongst cities Applying Commute Sheds to Regional Water Supplies

14. Application: Analyze the exports of water supply benefits amongst cities, illustrating their virtual connection Analysis Steps: 1. Find number of resident workers using OnTheMap 2. Estimate economic impact generated by workers 3. Determine portion exported by commuting workers Unit of Comparison: city boundaries – As a proxy for water utility service areas Exports of Water Supply Benefits

15. GDP is standard unit of economic impact City-level GDP not available Used primary job earnings per worker reported by OnTheMap to estimate economic impact Monthly EarningsWorkers Estimate Product Months Per Year <$1,20036,639x$1,200=43,966,800x12=527,601,600 $1,201 to $3,40070,128x$3,400=238,435,200x12=2,861,222,400 > $3,40072,216x$6,800=491,068,800x12=5,892,825,600 ANNUAL ECONOMIC IMPACT Supported by RALEIGH =$9,281,649,600 Exports of Water Supply Benefits

16. UPPER NEUSE BASIN Water Supply Benefits Supported by Each City In Terms of Annual Economic Impact of Residents, 2006 UPPER NEUSE BASIN Water Supply Benefits Supported by Each City In Terms of Annual Economic Impact of Residents, 2006 DURHAM $4,590 million HILLSBOROUGH $149 million SOUTH GRANVILLE $126 million SOUTH GRANVILLE $126 million RALEIGH $9,282 million

17. $9,281 million $8,482 million $8,482 million Durham -$800 million Hillsborough -$6.2 million South Granville -$4.9 million $8,470 million $8,470 million $8,358 million $8,358 million Chapel Hill -$113 million $7,554 million $7,554 million Jordan Lake -$803 million Kerr Lake -$31.8 million $7,522 million $7,522 million RALEIGH $4,713 million (50.5% retained) RALEIGH $4,713 million (50.5% retained) All Other Basins -$2,809 million $8,475 million $8,475 million RALEIGH Water Supply Benefits Exported In Terms of Annual Economic Impact of Residents, 2006 RALEIGH Water Supply Benefits Exported In Terms of Annual Economic Impact of Residents, 2006

18. Raleigh -$503 million Hillsborough -$22 million DURHAM $2,303 million (50.2% retained) DURHAM $2,303 million (50.2% retained) Chapel Hill -$500 million Jordan Lake -$205 million Kerr Lake -$16 million All Other Basins -$1,033 million DURHAM $4,057 million DURHAM $4,057 million DURHAM $4,590 million DURHAM $4,590 million South Granville -$7.2 million DURHAM Water Supply Benefits Exported In Terms of Annual Economic Impact of Residents, 2006 DURHAM Water Supply Benefits Exported In Terms of Annual Economic Impact of Residents, 2006

19. RALEIGH -$296 million to Durham DURHAM Net Imports of $349 million HILLSBOROUGH -$23.2 million to Durham -$2.0 million to Raleigh SOUTH GRANVILLE -$28.6 million to Durham -$0.2 million to Hillsborough -$17.3 million to Raleigh SOUTH GRANVILLE -$28.6 million to Durham -$0.2 million to Hillsborough -$17.3 million to Raleigh UPPER NEUSE BASIN Water Supply Benefits Net Exports In Terms of Annual Economic Impact of Residents, 2006 UPPER NEUSE BASIN Water Supply Benefits Net Exports In Terms of Annual Economic Impact of Residents, 2006

20. CHAPEL HILL Net Exports: -$191 million ~83% from Durham JORDAN LAKE Net Imports: $841 million ~50% to Durham ~50% to Raleigh KERR LAKE Net Imports: $26 million ~75% to Raleigh UPPER NEUSE BASIN Water Supply Benefits Net Exports In Terms of Annual Economic Impact of Residents, 2006 UPPER NEUSE BASIN Water Supply Benefits Net Exports In Terms of Annual Economic Impact of Residents, 2006

21. RESULTS Amongst Upper Neuse water systems, Durham is a net importer of water supply benefits – Durham is a net importer of workers – These workers are supported by other cities water supplies Amongst regional basins, the Upper Neuse is a net importer of water supply benefits, especially from Jordan Lake Exports of Water Supply Benefits

22. APPLICATIONS FOR DECISION-MAKING Reveals the interdependence of cities within and near the Upper Neuse River Basin Helps visualize virtual exports of water resources Can inform negotiations and decisions – Intra- and inter-basin water transfer agreements – Joint financing of new water infrastructure Exports of Water Supply Benefits

23. Conclusions Novel application of commute shed analysis OnTheMap can help analyze the exports of water supply benefits amongst cities, illustrating this virtual connection A versatile, easily-accessible tool to complement more costly research such as valuation and modeling analysis

24. COVER PHOTO CREDITS: traffic scene: A.F. Silva; Lake Michie aerial view: City of Durham