Across the globe, water sources are managed to supply energy, drinking water, grow food, and control floods. To meet our increasing needs, water planners are struggling to secure adequate supplies. However, with progressive policies to guide careful planning and management, human needs for water can be met while maintaining freshwater ecosystem health.

In recent decades, scientists have amassed considerable evidence that naturally-varying water flows are essential to the health and sustainability of freshwater ecosystems.

Environmental flows refer to the quality, quantity and timing of water flows required to sustain healthy freshwater ecosystems and the benefits they provide to human communities. Integrating environmental flow considerations into water management results in healthier freshwater ecosystems that benefit nature and people. 

The Nature Conservancy provides global leadership in environmental flow science and management, and informs policies to protect and restore rivers for nature and for people.

Tools, Resources and Training

Upcoming courses on environmental flows

Technologies including the Indicators of Hydrologic Alteration (IHA) software, flow restoration database and the Regime Prescription Tool (RPT) to aide freshwater practitioners can be found by clicking here.

Journal Articles about Freshwater Conservation

Suggested articles for Environmental Flow Practitioners:

Brown, C. and King, J. 2006. Environmental flows: Striking the balance between development and resource protection. Ecology and Society 11(2): 26. [online} URL: http://www.ecologyandsociety.org/vol11/
(Reprinted here with permission from the author.)

Arthington, A.H., Bunn, S.E., Poff, N.L., and R.J. Naiman. 2006. The Challanege of Providing Environmental Flow Rules to Sustain River Ecosysytems. Ecological Applications 16(4):1311-1318. 

Richter, B.D., Warner, Andrew T., Meyer, Judy L., and Lutz, Kim. 2006. A Collaborative and Adaptive Process for Developing Environmental Flow Recommendations.  (.pdf, 558 kb)

Richter, B.D., Roos-Collins, R, and Fahlund, A.C. A Framework for Ecologically Sustainable Water Management. Hydro Review, August 2005 © HCI Publications (.pdf 261kb)

Richter, B.D., R. Mathews, D.L. Harrison, and R. Wigington. 2003. Ecologically sustainable water management: managing river flows for ecological integrity. Ecological Applications 13:206-224.
View the paper (.pdf, 361 kb)
(This paper is posted with the permission of the Ecological Society of America.)

Baron, J.S., N.L. Poff, P.L. Angermeier, C.N. Dahm, P.H. Gleick, N.G. Hairston, R.B. Jackson, C.A. Johnston, B.D. Richter, and A.D. Steinman. 2002. Meeting ecological and societal needs for freshwater. Ecological Applications 12:1247-1260.
View the paper (.pdf, 196 kb)
(This paper is posted with the permission of the Ecological Society of America.)

Richter, B.D. and H.E. Richter. 2000. Prescribing flood regimes to sustain riparian ecosystems along meandering rivers. Conservation Biology 14:1467-1478.
View the paper (.pdf, 1.1 MB)
(This paper is posted with the permission of Blackwell Publishing.)

Silk, N., J. McDonald, and R. Wigington. 2000. Turning instream flow water rights upside down. Rivers 7:298-313.
View the paper (.pdf, 116 kb)
(This paper is reprinted from Rivers Vol. 7 (4), 2000, with permission from S.E.L. & Associates).

Richter, B.D., J.V. Baumgartner, D.P. Braun, and J. Powell. 1998. A spatial assessment of hydrologic alteration within a river network. Regulated Rivers 14:329-340.
View the paper (.pdf, 772 kb)
(This paper is posted with the permission of John Wiley and Sons, Inc.)

Poff, N.L., J.D. Allan, M.B. Bain, J.R. Karr, K.L. Prestegaard, B.D. Richter, R.E. Sparks, and J.C. Stromberg. 1997. The natural flow regime: a paradigm for river conservation and restoration. BioScience 47:769-784.
View the paper (.pdf, 1.8 MB)
(This paper is posted with permission of The American Institute of Biological Sciences (AIBS).)

Richter, B.D., D.P. Braun, M. A. Mendelson, and L.L. Master. 1997. Threats to imperiled freshwater fauna. Conservation Biology 11:1081-1093.
View the paper (.pdf, 1.3 MB)
(This paper is posted with the permission of Blackwell Publishing.)

Richter, B.D., J.V. Baumgartner, R. Wigington, and D.P. Braun. 1997. How much