ii. Hydrobiological (NMx –Technical Annex 5) 6.2. Methodologies 3. Objective 4. Field of application 5. Normative references of special interest for the NMx 6.3. Environmental flows proposal content 1. Background 2. Scientific principles or foundations Sergio Salinas Program Officer Conservation of aquatic ecosystems WWF-México [email protected] Eugenio Barrios Director, Water Program WWF-México [email protected] For further information please contact: Poff N.L., J.D. Allan, M.B. Bain, J.R. Karr, K.L. Prestegaard, B. Richter, R. Sparks and J. Stromberg. 1997. The natural regime: a new paradigm for riverine conservation and restoration. BioScience 47:769-784. Davies S.P. y Jackson S.K. 2006. The Biological Condition Gradient: A Descriptive Model for Inter- preting Change in Aquatic Ecosystems. Ecological Applications: Vol. 16, No. 4 pp. 1251–1266. USEPA. 2005. Use of Biological Information to Better Designated Aquatic Life Uses in State and Tribal Water Quality Standards: Tiered Aquatic Life Uses. 1 2 WWF-FGRA ALLIANCE MODEL: Systematization of results and national experiences; international experiences reviewed 20 diagnostic workshops and EF with participation of more than 100 experts (water users, academics, government employees, communities and NGO) Three Mexican river basins Figure 1. Process to develop NMx from WWF-FGRA Alliance model Figure 2. Scientific principles of the NMx Figure 5. EF regime (low flows and high pulses) projected in a hypothetical period of 10 years COMPONENTS OF HYDROLOGICAL REGIME Maintenance of habitat diversity and connectivity X X X X X X X X X X X X X X X Drought episodes (red) Seasonal pattern of low flows (green) High pulses regime and floods (blue) Maintenance of appropiate hydrodynamic conditions Maintenance of seasonal habitat diversity Synchronization of environmental patterns Control of presence and abundance of species Good physical-chemical conditions of water and sediments Improvement of geomorphological dynamic conditions Control and improvement of hydrological processes ECOLOGICAL FUNCTIONS Caudal (m 3 / seg) 1800 1-feb 1-mar 1-abr 1-may 1-jun 1-jul 1-ago 1-sep 1-oct 1-nov 1-dic 1-ene 1600 1400 1200 1000 800 600 400 200 0 RIVER IN NATURAL CONDITIONS 1 2 3 4 5 6 STRESSOR GRADIENT BIOLOGICAL CONDITION Natural Degrated Low High Minimal loss of species Some sensitive species maintained but notable replacement by more tolerant taxa Some replacement of sensitive-rare species Tolerant species show increasing dominance Native or natural condition Severe alteration of structure and function NATURAL FLOW PARADIGM 1 BIOLOGICAL CONDITION GRADIENT 2 Hydrological Basins Environmental objective Administrative hydrological region* Peninsula of Yucatan aquifers** International limit *Hydrological basins in white are still in analysis to obtain their environmental objectives **Environmental objective according aquifers information in Peninsula of Yucatan Environmental objective Ecological importance • NPA's • Conservation priorities • Ramsar sites Water pressure • Allocations among water users Ecological importance Water pressure CRITERIA Low Medium High Very High Very High A A B C High A B C D Medium B C C D Low B C D D Figure 3. Conceptual model, criteria matrix and environmental objectives map Figure 4. EF regime using reference values 01-Jan 01-Feb 01-Mar 01-Apr 01-May 01-Jun 01-Jul 01-Aug 01-Sep 01-Oct 01-Nov 01-Dec 50 0 100 150 200 250 300 350 400 450 Flow (m 3 / sec) MEAN MONTHLY FLOW VERY GOOD GOOD MODERATE DEFICIENT DAILY AVERAGE FLOW EF chosen 6. General specifications 6.1. Environmental objectives Institutions involved in the Mexican Norm project Figure 6. Methodological framework for EF analysis through physical habitat modeling according to preferences of certain species. Selection of critical points Field trip and initial recognition selection 1D/2D 2nd Survey (Spring - Summer) Hydrometry of the reach Additional survey (Validation and capture of additional data) Construction of habitat models Calibration of habitat models Habitat mapped Selection of the reach Connectivity validation Temporal series of habitat Minimum flows range recommendation Obtaining of curves HPU-Q 1 st Survey (Winter-Spring) Topography of riverbed and riverside Hydrometry of the reach Results Generation of specific preference curves 1 st Survey Winter - Spring Adults - Alevin 2 nd Survey Spring - Summer Adults - Alevin - Young 3 rd Survey Summer - Autumn Young - Adults Generation of preference curves Figure 7. Conceptual model for an holistic methodology development Preliminary activities Selection of reference sites Discussion workshops First proposal of EF Integration of proposal in final report Determination study units in the basin Information • Hydrology Hydraulics Geomorphology Water quality Geohydrology Botany Ictiology Aquatic macroinvertebrates Sociology • • • • • • • b • • Current ecological state Ecological importance and sensitivity Current water pressure state Environmental objectives Hydrological sceneries Proposal of EF agreed • • • • • Federal Electricity Commission, National Water Commission, Natural Protected Areas Commission, National Commission for Knowledge and Use of Biodiversity, Institutes of Biology and Engineering of the National University of Mexico, Mexican In- stitute of Water Technology, National Institute of Ecology, Sec- retariat of Environment and Natural Resources, The Nature Conservancy and World Wildlife Fund for Nature, Inc. Mexico Program. Generation of previsionable curves and comparission with literature Generation of preference curves and comparission with experts Since 2004, the Alliance conformed by World Wildlife Fund for Nature (WWF) and Gonzalo Río Arronte Foundation, I.A.P. (FGRA), in collaboration with National Water Commission (CONAGUA) and others federal agencies, as well as academic institutions, Non-Governmental Organizations (NGO), water users and rural com- munities, has developed three different proposals of environmental flows (EF) in river basins with different conservation, water pressure and management con- texts: i) Conchos river in Chihuahua; ii) Copalita-Zimatán-Huatulco rivers in Oaxaca; and iii) San Pedro Mezquital river in Zacatecas, Durango and Nayarit. From 33 sites analyzed in detail in the three river basins, in 73% of the cases EF occurs under current conditions; in 21%, management requires regulation in the conditions of water extraction and in operation of infrastructure; and only in 6% is necessary to make adjustments in user’s water allocation. These results were systematized for the proposed Mexican Norm (NMx) (Figure 1). Two core principles are followed to determine the hydrological requirements of aquatic ecosystems, and therefore they are the foundation of the EF Mexican Norm (Figure 2). These principles allow to identify valid EF methodologies and set a nor- mative framework up. Any given methodology to determine EF regime will be valid if it leads to practice of the key scientific principles, for example: • It must allow for understanding of the ecological significance of each flow regime component, and generate proposals from a functional point of view, for its conservation or reestablishment • The proposal must consider the natural hydrological variability for ordinary (low flows) and extraordinary (high pulses and floods) conditions • It recognizes that an aquatic ecosystem modifies its features in response to an increase in stress levels, and therefore, it allows adjustment to pro- posals to the environmental objectives or conservation of the river. To establish the technical procedures and specifications for determining EF regime in streams or national water bodies in a hydrological basin. Water allocation, infrastructure, or any other work that involves water transfer among basins and the like, which requires an Environmental Impact Assessment. All streams and water bodies whose availability agreements published in the Offi- cial Government Gazette did not considered flows for aquatic ecosystems conser- vation. NOM-011-CONAGUA-2000. Conservation of the resource of water – which estab- lishes the specifications and methodology for determining the mean annual avail- ability of the nation’s waters. NOM-059-SEMARNAT-2010. Environmental protection – Wildlife species of flora and fauna native to Mexico – Categories of risk and specifications for its inclu- sion, exclusion or change – List of species in risk. The described methods are considered as minimum technical requirements and do not exclude the implementation of complementary or more precise methods. The EF regime should be determined based on the associated environmental ob- jective, according to the basin’s ecological importance and water pressure (NMx– Technical Annex 1), whether surface streams, water bodies of diverse kinds, or as part of the associated aquifer’s natural discharge, to conserve and protect the environmental conditions and promote ecological balance. Environmental objectives represent the ecological state that is intended to be ob- tained or preserved in the basin. They establish the relationship between the value of conservation (ecological importance) and its implication for the produc- tive uses of water (water pressure) (Figure 3). i. Hydrological (NMx – Technical Annex 2, 3 y 4) Application: Without conflicts for water use and with hydrological regime unaltered (Figure 4) • Procedure based on reference values as percentages ranges of mean annual runoff and taken to a monthly scale Applicacion: With presence of water infrastructure (i.e. hydropower plants) and altered hydrological regime (Figure 5), the method should define: • Seasonal low flows regime for wet, average, dry and very dry hydro- logical conditions • Intra-annual (Type I) and inter-annual (low and mid magnitude – Type II and III, respectively) high pulses regimes with their respective attri- butes of magnitude, duration frequency, timing, and rate of change Habitat simulation models to project the physical habitat and its changes due the flows. It has the purpose of quantifying habitat preferences of species, or one in particular that could be taken as an objective (Figure 6). Frequently in these models hydraulic variables are used in the determina- tion of the connectivity of rivers, floods and channel capacities. Among the most used models are: • Instream Flow Incremental Methodology (IFIM) • Physical Habitat Simulation System (PHABSIM) iii. Holistic (NMx – Technical Annex 6) Highly recommended for those cases where detailed proposal of EF is needed or required due to a river’s complexity, social conflicts or difficulties. Focused on particularities of the zone of interest, and specifically, identify the ecologi- cal significance of hydrological regime components and their relationship with the basin’s ecological importance and the impact on water uses (Figure 7). Methodologies of this kind are: • Building Block Methodology (BBM) • Downstream Response to Impose Flow Transformation (DRIFT) • Benchmarking • Ecological Limits Of Hydrologic Alteration (ELOHA) EF Mexican Norm procedure results will be presented according to gauging sta- tions located in the river basin (headquarters or highlands, midlands and lowlands) and at each sub-basin discharge. The report should have the following content: i. Description of the hydrological basin ii. Selection and characteristics of the sub-basin iii. Environmental flows per basin a) Description of the methodology used, justification and preliminary de- termination of environmental flows b) Reference sites and proposal of environmental flows iv. Annexes. Technical data and other detailed information of each analyzed reference site MEXICAN NORM (NMX) THAT ESTABLISHES THE PROCEDURE FOR ENVIRONMENTAL FLOW DETERMINATION IN HYDROLOGICAL BASINS ENVIRONMENTAL OBJECTIVE "A" Natural daily flow Natural monthly flow Environmental flow HIGH PULSES Type III Type I Type II 3500 3000 2500 2000 1000 500 0 1500 1 2 3 4 5 6 7 8 9 10 Flow (m 3 / sec)