With the implementation of the Official Mexican Standard NOM-011-CONAGUA-2000 [1], the water balance of 730 basins has been calculated and its water availability agreement is published. This rule points out to allocate water for the environment only as an annual volume since methods for estimating environmental flows were not standardized in the country. For this reason, The Water Agency (CONAGUA) issued the standard NMX-AA-159-SCFI-2012 [2], to assess environmental flows needed both, at the strategic level in Integrated Water Resources Management (IWRM), or as part of the Environmental Impact Assessment (EIA) of large hydraulic projects. For over ten years, this standard was developed and finally published in September 2012 [3]. It explains different methods from hydrological to holistic approaches, with examples for the country. Its application will cover the urgent need to preserve water for ecosystems in watersheds with high ecological importance and low stress for water use. In this paper, an analysis of the environmental flow standard and examples of the suggested hydrological methods are presented. For its implementation, some steps are taking place, mainly establishing environmental water reserves and building capacities. In addition, environmental allocations are becoming a common practice for all water projects, as well as setting limits to hydrological alterations by hydroelectric dams. The standard promotes the use of technical integration tools to analyze the responses of ecosystems to changes in the flow regime and adaptive management under different scenarios of water use. Although the main steps have been taken, its implementation as mandatory rule will take time.
KeywordsEnvironmental FlowsHydrological MethodsMexican Standard
NOM-011-CNA-2000, “Norma Oficial Mexicana, Conservación del Recurso Agua. Que Establece las Especificaciones y el Método para Disponibilidad Media Anual de las Aguas Nacionales,” DOF 17-Abril-2002, México, p. 20.
NMX-AA-159-SCFI-2012, “Norma Mexicana. Que Establece el Procedimiento para la Determinación del Caudal Ecológico en Cuencas Hidrológicas,” DOF 20 de Septiembre de 2012, México, p. 123.
P. A. E. Lis, M. A. G. Balandra and P. S. Fabela, “Requerimientos para Implementar el Caudal Ambiental en México,” Instituto Mexicano de Tecnología del Agua, Alianza World Wildlife Fund/Fundación Gonzalo Río Arronte. Programa Hidrológico Internacional UNESCO, SEMARNAT, 2007, p. 176.
T. Annear, I. Chisholm, H. Beecher and A. Locke, “Instream flows for Riverine Resource Steweardship,” Revised Edition, Instream Flow Council, Cheyenne, 2004, p. 268.
E. García, R. González, P. Martínez, J. Athala and G. Paz-Soldán, “Guía de Aplicación de los Métodos de cálculo de Caudales de Reserva Ecológicos en México, Colección,” CNA-IMTA-SEMARNAP, México D.F., 1999, p. 190.
S. Postel and B. Richter, “Rivers for Life: Managing Water for People and Nature,” Island Press, Washington DC, 2003.
N. L. Poff, “Managing for Variability to Sustain Freshwater Ecosystems,” Journal of Water Resources Planning and Management, Vol. 135, No. 1, 2009, pp. 1-4.
A. H. Arthington, S. E. Bunn, N. L. Poff and R. J. Naiman, “The Challenge of Providing Environmental Flow Rules to Sustain River Ecosystems,” Ecological Applications: A Publication of the Ecological Society of America, Vol. 16, No. 4, 2006, pp. 1311-1138.
R. E. Tharme, “A Global Perspective on Environmental Flow Assessment: Emerging Trends in the Development and Application of Environmental Flow Methodologies for Rivers,” River Research and Applications, Vol. 19, No. 5-6, 2003, pp. 397-441. http://dx.doi.org/10.1002/rra.736
M. Acreman and M. J. Dunbar, “Defining Environmental River Flow Requirements a Review,” Hydrology and Earth System Sciences, Vol. 8, No. 5, 2004, pp. 861-876. http://dx.doi.org/10.5194/hess-8-861-2004
B. D. Richter, J. V. Baumgartner, R. Wigington and D. P. Braun, “How Much Water Does A River Need?” Freshwater Biology, Vol. 37, No. 1, 1997, pp. 231-249. http://dx.doi.org/10.1046/j.1365-2427.1997.00153.x
B. D. Richter, “Short Communication Re-Thinking Environmental Flows: From Allocations and Reserves to Sustainability Boundaries,” River Research and Applications, Vol. 26, No. 8, 2010, pp. 1052-1063.
J. O’Keeffe and T. Le Quesne, “Keeping Rivers Alive— A Primer on Environmental Flows and Their Assessment,” World Wildlife Found—Water Security Series 2, Surrey, 2009.
TNC (The Nature Conservancy), “Indicators of Hydrologic Alteration,” Version 7.1 User’s Manual, 2009, p. 81.
WWF and Fundación Gonzalo Río Arronte, “Guía Para la Determinación de Caudal Ecológico en México Sistematización de Experiencias de la Alianza WWF,” Fundación Gonzalo Río Arronte I.A.P., Mexico D.F., 2011.
M. J. DUNBAR and M. C. Acreman, “Applied Hydro-Ecological Science for the Twenty-First Century,” In: M. C. Acreman, Ed., Hydro-Ecology: Linking Hydrology and Aquatic Ecology (Proceedings of an International Workshop (HW2). Centre for Ecology and Hydrology (Formerly Institute of Hydrology), Wallingford, Oxfordshire, 2001, pp. 1-18.
R. Hirji and R. Davis, “Environmental Flows in Water Resources Policies, Plans and Projects. Case Studies,” Water Resources, No. 117. Washington DC, 2009, p. 181.
N. L. Poff, J. D. Allan, M. A. Palmer, D. D. Hart, B. D. Richter, A. H. Arthington, K. H. Rogers, J. L. Meyer and J. A. Stanford, “River Flows and Water Wars: Emerging Science for Environmental Decision Making,” Frontiers in Ecology and the Environment, Vol. 1, No. 6, 2003, pp. 298-306. http://dx.doi.org/10.1890/1540-9295(2003)001[0298:RFAWWE]2.0.CO;2
A. H. Arthington, R. J. Naiman, M. E. McClain and C. Nilsson, “Preserving the Biodiversity and Ecological Services of Rivers: New Challenges and Research Opportunities,” Freshwater Biology, Vol. 55, No. 1, 2009, pp. 1-16. http://dx.doi.org/10.1111/j.1365-2427.2009.02340.x
C. Nilsson and B. M. Renofalt, “Linking Flow Regime and Water Quality in Rivers: A Challenge to Adaptive Catchment Management,” Ecology and Society, Vol. 13, No. 2, 2008, 20 p.
C. J. Vorosmarty, P. B. McIntyre, M. O. Gessner, D. Dudgeon, A. Prusevich, P. Green, S. Glidden, S. E. Bunn, C. A. Sullivan, C. R. Liermann and P. M. Davies, “Global Threats to Human Water Security and River Biodiversity,” Nature, Vol. 467, 2010, pp. 555-561. http://dx.doi.org/10.1038/nature09440
The Brisbane Declaration, The Brisbane Declaration at 10th International Riversymposium & Environmental Flows Conference, Brisbane, 2007.
H. Chen, L. Ma, W. Guo, Y. Yang, T. Guo and C. Feng, “Linking Water Quality and Quantity in Environmental Flow Assessment in Deteriorated Ecosystems: A Food Web View,” Plos One, Vol. 8, 2013, No. 7, p. 13.
WWF, Fundación Río Arronte, and CONAGUA, “Norma Mexicana de Caudal Ecológico—Una PolíTica Pública Para la Gestión del Agua a Través de la Conservación del Régimen Hidrológico,” Mexico D.F., 2012.
CONAGUA, “Identificación de Reservas Potenciales de agua Para el Medio Ambiente en México,” Comisión Nacional del Agua, Alianza WWF-Fundación Gonzalo Río Arronte I.A.P, Primera Ed. Mexico, 2011, p. 87.
D. L. Tennant, “Instream Flow Regimens for Fish, Wildlife, Recreation and Related Environmental Resources,” Fisheries, Vol. 1, No. 4, 1976, pp. 6-10. http://dx.doi.org/10.1577/1548-8446(1976)001 2.0.CO;2
J. King, R. Tharme and M. de Villier, “Environmental Flow Assessments for Rivers: Manual for the Building Block Methodology,” Water Research Commission, SAF, Cape Town, 2008.
N. L. Poff, B. D. Richter, A. H. Arthington, S. E. Bunn, R. J. Naiman, E. Kendy, M. Acreman, C. Apse, B. P. Bledsoe, M. C. Freeman, J. Henriksen, R. B. Jacobson, J. G. Kennen, D. M. Merritt, J. H. O’Keeffe, J. D. Olden, K. Rogers, R. E. Tharme and A. Warner, “The Ecological Limits of Hydrologic Alteration (ELOHA): A New Framework for Developing Regional Environmental Flow Standards,” Freshwater Biology, Vol. 55, No. 1, 2010, pp. 147-170. http://dx.doi.org/10.1111/j.1365-2427.2009.02204.x