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Unintended consequences of water conservation on the use of treated municipal wastewater

Nature Sustainability volume 3, pages 628–635 (2020)Cite this article

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Abstract

Municipal water managers are intensifying efforts to reduce urban water use and increase the reliability of local water supplies to combat rising water scarcity and drought. Incentivizing increases in water-use efficiency and mandating conservation are two strategies to rein in demand. Concurrently, local water supplies are being augmented through investments in reclaiming and treating municipal wastewater. Although reducing urban water consumption is necessary to deal with population growth and a more variable climate, it does come at a cost. In particular, cutting back on indoor water consumption impacts the generation and quality of wastewater, which can have widespread and underappreciated consequences on human society and the environment. Here, to quantify these impacts, we tracked monthly effluent flow, salinity levels and the properties of 34 wastewater treatment plants throughout Southern California from 2013 to 2017—a period that included extreme drought and abundant precipitation. Our analysis demonstrates that conservation measures significantly reduced effluent flow and increased effluent salinity (P value ≤ 0.05). Our findings further highlight the need for policymakers to recognize the interdependencies and complexities within a water system.

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Fig. 1: Practical examples of water conservation in municipalities.
Fig. 2: The locations of the sample WWTPs and corresponding water agency flow reductions.
Fig. 3: The monthly relationship between changes in effluent flow, GPCD and TDS.
Fig. 4: Analysis of the relationship between conservation policies and changes in effluent flow and TDS.
Fig. 5: Analysis of the relationship between conservation policies and changes in effluent TDS with and without controlling for the salinity levels for the source water.

Data availability

All data that support the findings of this study are available from the corresponding authors on request.

References

  1. Schwabe, K., Albiac, J., Connor, J. D., Hassan, R. M. & González, L. M. Drought in Arid and Semi-Arid Regions: A Multi-Disciplinary and Cross-Country Perspective (Springer, 2013).

  2. Berbel, J. & Esteban, E. Droughts as a catalyst for water policy change. Analysis of Spain, Australia (MDB), and California. Glob. Environ. Change 58, 101969 (2019).

    Article  Google Scholar 

  3. Trindade, B., Reed, P. & Characklis, G. Deeply uncertain pathways: integrated multi-city regional water supply infrastructure investment and portfolio management. Adv. Water Resour. 134, 103442 (2019).

    Article  Google Scholar 

  4. Olmstead, S. M. The economics of managing scarce water resources. Rev. Environ. Econ. Policy 4, 179–198 (2010).

    Article  Google Scholar 

  5. Olmstead, S. M. & Stavins, R. N. Comparing price and nonprice approaches to urban water conservation. Water Resour. Res. 45, W04301 (2009).

    Article  Google Scholar 

  6. Gilligan, J. M. et al. Urban water conservation policies in the United States. Earth’s Future 6, 955–967 (2018).

    Article  Google Scholar 

  7. Nemati, M., Buck, S. & Soldati, H. The effect of social and consumption analytics on residential water demand. In The Association of Environmental and Resource Economists (AERE) Session, American Economic Association Annual Meeting 1–47 (SSRN, 2016); http://dx.doi.org/10.2139/ssrn.2877233

  8. Nemati, M. & Penn, J. The impact of social norms, feedback, and price information on conservation behavior: a meta-analysis. In Agricultural and Applied Economics Association Annual Meeting 1–24 (Agricultural and Applied Economics Association, 2018); https://doi.org/10.22004/ag.econ.274431

  9. Brent, D. A., Cook, J. H. & Olsen, S. Social comparisons, household water use, and participation in utility conservation programs: evidence from three randomized trials. J. Assoc. Environ. Resour. Econ. 2, 597–627 (2015).

    Google Scholar 

  10. Baerenklau, K. A., Schwabe, K. A. & Dinar, A. The residential water demand effect of increasing block rate water budgets. Land Econ. 90, 683–699 (2014).

    Article  Google Scholar 

  11. Schwabe, K. A., Baerenklau, K. A. & Dinar, A. Coping with water scarcity: the effectiveness of allocation-based pricing and conservation rebate programs in California’s urban sector. Policy Matters 6, 1–7 (2014).

    Google Scholar 

  12. Grafton, R. Q., Chu, L. & Wyrwoll, P. The paradox of water pricing: dichotomies, dilemmas, and decisions. Oxf. Rev. Econ. Policy 36, 86–107 (2020).

    Article  Google Scholar 

  13. Hanak, E. et al. California’s Water: Water for Cities (Public Policy Institute of California, 2018).

  14. Tran, Q. K., Jassby, D. & Schwabe, K. A. The implications of drought and water conservation on the reuse of municipal wastewater: recognizing impacts and identifying mitigation possibilities. Water Res. 124, 472–481 (2017).

    Article  CAS  Google Scholar 

  15. Municipal Wastewater Recycling Survey (State Water Resources Control Board, 2017); https://go.nature.com/35aqnL1

  16. Stokes, J. R. & Horvath, A. Energy and air emission effects of water supply. Environ. Sci. Technol. 43, 2680–2687 (2009).

    Article  CAS  Google Scholar 

  17. Chappelle, C., Jassby, D., McCann, H., Schwabe, K. & Szeptycki, L. Managing Wastewater in a Changing Climate (Public Policy Institute of California, 2019).

  18. Grant, S. B. et al. Taking the “waste” out of “wastewater” for human water security and ecosystem sustainability. Science 337, 681–686 (2012).

    Article  CAS  Google Scholar 

  19. Grafton, R. et al. The paradox of irrigation efficiency. Science 361, 748–750 (2018).

    Article  CAS  Google Scholar 

  20. Dumont, A., Mayor, B. & López-Gunn, E. Is the rebound effect or Jevons paradox a useful concept for better management of water resources? Insights from the irrigation modernisation process in Spain. Aquat. Pr. 1, 64–76 (2013).

    Article  Google Scholar 

  21. Alcott, B. Jevons’ paradox. Ecol. Econ. 54, 9–21 (2005).

    Article  Google Scholar 

  22. Di Baldassarre, G. et al. Water shortages worsened by reservoir effects. Nat. Sustain. 1, 617–622 (2018).

    Article  Google Scholar 

  23. Gohari, A. et al. Water transfer as a solution to water shortage: a fix that can backfire. J. Hydrol. 491, 23–39 (2013).

    Article  Google Scholar 

  24. Kallis, G. Coevolution in water resource development: the vicious cycle of water supply and demand in athens, greece. Ecol. Econ. 69, 796–809 (2010).

    Article  Google Scholar 

  25. Scott, C. A., Vicuña, S., Blanco Gutiérrez, I., Meza, F. & Varela Ortega, C. Irrigation efficiency and water-policy implications for river-basin resilience. Hydrol. Earth Syst. Sci. 18, 1339–1348 (2014).

    Article  Google Scholar 

  26. Making Water Conservation a California Way of Life (California Department of Water Resources & State Water Resources Control Board, 2018); https://water.ca.gov/LegacyFiles/wateruseefficiency/conservation/docs/20170407_EO_B-37-16_Final_Report.pdf

  27. Mann, M. E. & Gleick, P. H. Climate change and California drought in the 21st century. Proc. Natl Acad. Sci. USA 112, 3858–3859 (2015).

    Article  CAS  Google Scholar 

  28. Shukla, S., Safeeq, M., AghaKouchak, A., Guan, K. & Funk, C. Temperature impacts on the water year 2014 drought in California. Geophys. Res. Lett. 42, 4384–4393 (2015).

    Article  Google Scholar 

  29. Mount, J. & Hanak, E. Water Use in California (Public Policy Institute of California, 2014).

  30. Schwabe, K., Nemati, M., Landry, C. & Zimmerman, G. Water markets in the western United States: trends and opportunities. Water 12, 233 (2020).

    Article  Google Scholar 

  31. Buck, S., Nemati, M. & Sunding, D. L. The welfare consequences of the 2015 California drought mandate: evidence from new results on monthly water demand. In Agricultural and Applied Economics Association Annual Meeting 1–38 (Agricultural and Applied Economics Association, 2016); https://doi.org/10.22004/ag.econ.236049

  32. Nemati, M., Buck, S. & Sunding, D. Cost of California’s 2015 drought water conservation mandate. ARE Update 21, 9–11 (2018).

    Google Scholar 

  33. Proposition 1 Bond Accountability (California Natural Resources Agency, 2019); http://bondaccountability.resources.ca.gov/p1.aspx

  34. Tran, Q. K., Schwabe, K. A. & Jassby, D. Wastewater reuse for agriculture: development of a regional water reuse decision-support model (RWRM) for cost-effective irrigation sources. Environ. Sci. Technol. 50, 9390–9399 (2016).

    Article  CAS  Google Scholar 

  35. Bertrand, M., Duflo, E. & Mullainathan, S. How much should we trust differences-in-differences estimates? Q. J. Econ. 119, 249–275 (2004).

    Article  Google Scholar 

  36. Halvorsen, R. & Palmquist, R. The interpretation of dummy variables in semilogarithmic equations. Am. Econ. Rev. 70, 474–475 (1980).

    Google Scholar 

  37. Cameron, A. C. & Trivedi, P. K. Microeconometrics: Methods and Applications (Cambridge Univ. Press, 2005).

  38. Wooldridge, J. M. Econometric Analysis of Cross Section and Panel Data (MIT Press, 2010).

  39. Angrist, J. D. & Pischke, J.-S. Mostly Harmless Econometrics: An Empiricist’s Companion (Princeton Univ. Press, 2008).

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Acknowledgements

We thank S. Wasif for the preparation of Fig. 1; and S. Erysian from the California Department of Water Resources, C. Nagai and B. Coffey from the Metropolitan Water District, and C. Berch from Jurupa Community Services District for data guidance and input.

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Authors and Affiliations

  1. School of Public Policy, University of California, Riverside, Riverside, CA, USA

    Kurt Schwabe & Mehdi Nemati

  2. Water Policy Center, Public Policy Institute of California, San Francisco, CA, USA

    Kurt Schwabe

  3. California Public Utilities Commission, San Francisco, CA, USA

    Refat Amin

  4. Los Angeles County Water Sanitation Districts, Whittier, CA, USA

    Quynh Tran

  5. Department of Civil and Environmental Engineering, University of California Los Angeles, Los Angeles, CA, USA

    David Jassby

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  1. Kurt Schwabe
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  2. Mehdi Nemati
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  5. David Jassby
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Contributions

K.S., M.N. and D.J. designed research. K.S., M.N., R.A. and Q.T. performed research. K.S., M.N., R.A., Q.T. and D.J. wrote the paper.

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Correspondence to Kurt Schwabe.

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Supplementary Information

Supplementary Tables 1–6.

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Schwabe, K., Nemati, M., Amin, R. et al. Unintended consequences of water conservation on the use of treated municipal wastewater. Nat Sustain 3, 628–635 (2020). https://doi.org/10.1038/s41893-020-0529-2

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