Determination of environmental flows in rivers using an integrated hydrological-hydrodynamic-habitat modelling approach.

We propose the novel integrated modelling procedure 3H-EMC for the determination of the environmental flow in rivers and streams; 3H-EMC combines Hydrological, Hydrodynamic and Habitat modelling with the use of the Environmental Management Classes (EMCs) that are defined by the Global Environmental Flow Calculator. We apply 3H-EMC in the Sperchios River in Central Greece, in which water abstractions for irrigation cause significant environmental impacts. Calculations of the hydrodynamic-habitat model, in which the large and the small chub are the main fish species, suggest discharge values that range from 1.0 m3/s to 4.0 m3/s. However, hydrological modelling indicates that it is practically difficult to achieve discharges that are higher than approximately 1.0-1.5 m3/s. Furthermore, legislation suggests significantly lower values (0.4-0.5 m3/s) that are unacceptable from the ecological point of view. This behaviour shows that a non-integrated approach, which is based only on hydrodynamic-habitat modelling does not necessarily result in realistic environmental flows, and thus an integrated approach is required. We propose the value of 1.0 m3/s as the "optimum" environmental flow for Sperchios River, because (a) it satisfies the habitat requirements, as expressed by the values of weighted useable area that are equal to 2180 and 1964 m2 for the large and small chub, respectively, and correspond to 82 and 95% of their respective maximum values, (b) it is consistent with the requirements of Environmental Classes A and B, whose percentiles are higher than 75% for discharge (77.2%) and for habitat availability (>83.5% for the large chub and >85.0% for the small chub), (c) it is practically achievable from the hydrological point of view, and (d) it is higher than the value proposed by the Greek legislation. The proposed modelling approach can be applied to any river or stream using the same or similar modelling tools, which should be linked via suitable coupling algorithms.

[1]  Maria Teresa Ferreira,et al.  Univariate functions versus fuzzy logic: Implications for fish habitat modeling , 2014 .

[2]  Donald L. Tennant.  Instream Flow Regimens for Fish, Wildlife, Recreation and Related Environmental Resources , 1976 .

[3]  Francisco Martínez-Capel,et al.  Microhabitat use by three endemic Iberian cyprinids in Mediterranean rivers (Tagus River Basin, Spain) , 2009 .

[4]  E. Aparicio,et al.  Assessing population status of Parachondrostoma arrigonis (Steindachner, 1866), threats and conservation perspectives , 2014, Environmental Biology of Fishes.

[5]  Joanna B. Whittier,et al.  Development and assessment of a landscape-scale ecological threat index for the Lower Colorado River Basin , 2011 .

[6]  Maria Teresa Ferreira,et al.  Microhabitat use by Iberian nase Chondrostoma polylepis and Iberian chub Squalius carolitertii in three small streams, north‐west Portugal , 2004 .

[7]  P. McIntyre,et al.  Global threats to human water security and river biodiversity , 2010, Nature.

[8]  S. Zogaris,et al.  Developing policy-relevant river fish monitoring in Greece: Insights from a nation-wide survey , 2016 .

[9]  M. T. Ferreira,et al.  Microhabitat use by endangered Iberian cyprinids nase Iberochondrostoma almacai and chub Squalius aradensis , 2008, Aquatic Sciences.

[10]  B. L. Lamb,et al.  Stream habitat analysis using the instream flow incremental methodology , 1998 .

[11]  W. Darwall,et al.  The Status and Distribution of the Freshwater Fish Endemic to the Mediterranean Basin , 2006 .

[12]  E. Dimitriou,et al.  Climate change impacts on a Mediterranean river and the associated interactions with the adjacent coastal area , 2017, Environmental Earth Sciences.

[13]  J. Hervouet.  Hydrodynamics of Free Surface Flows: Modelling with the Finite Element Method , 2007 .

[14]  Sylvie Gourlet-Fleury,et al.  Assessing Sustainability of Logging Practices in the Congo Basin’s Managed Forests: the Issue of Commercial Species Recovery , 2006 .

[15]  S. Saltveit,et al.  Seasonal and spatial microhabitat selection and segregation in young Atlantic salmon, Salmo salar L., and brown trout, Salmo trutta L., in a Norwegian river , 1990 .

[16]  Laurel Saito,et al.  Assessing Ecosystem Effects of Reservoir Operations Using Food Web–Energy Transfer and Water Quality Models , 2001, Ecosystems.

[17]  M. Meador,et al.  Relations between introduced fish and environmental conditions at large geographic scales , 2003 .

[18]  Brian Richter,et al.  Application of the Indicators of Hydrologic Alteration Software in Environmental Flow Setting 1 , 2007 .

[19]  P. Bradshaw,et al.  Turbulence Models and Their Application in Hydraulics. By W. RODI. International Association for Hydraulic Research, Delft, 1980. Paperback US $15. , 1983, Journal of Fluid Mechanics.

[20]  A. Arthington,et al.  Basic Principles and Ecological Consequences of Altered Flow Regimes for Aquatic Biodiversity , 2002, Environmental management.

[21]  Angela H. Arthington,et al.  Environmental flow requirements of fish in Lesotho rivers using the DRIFT methodology , 2003 .

[22]  Habitat patchiness affects distribution and microhabitat use of endangered Mira chub Squalius torgalensis (Actinopterygii, Cypriniformes) , 2014, Hydrobiologia.

[23]  A. Stamou,et al.  Response of freshwater macroinvertebrates to rainfall-induced high flows: A hydroecological approach , 2017 .

[24]  John Heasley,et al.  Users' manual for the Hydroecological Integrity Assessment Process software (including the New Jersey Assessment Tools) , 2006 .

[25]  Sovan Lek,et al.  Modelling roach (Rutilus rutilus) microhabitat using linear and nonlinear techniques , 2000 .

[26]  T. Lambert,et al.  Development of habitat suitability criteria for trout in small streams , 1989 .

[27]  Cate Brown,et al.  Environmental Flows: Striking the Balance between Development and Resource Protection , 2006 .

[28]  N. LeRoy Poff,et al.  The ecological limits of hydrologic alteration (ELOHA): a new framework for developing regional environmental flow standards , 2007 .

[29]  D. Pont,et al.  Ecological traits of fish assemblages from Mediterranean Europe and their responses to human disturbance , 2007 .

[30]  Elias Dimitriou,et al.  Assessing water stress in Mediterranean lotic systems: insights from an artificially intermittent river in Greece , 2011, Aquatic Sciences.

[31]  K. Soulis,et al.  Potential impacts of climate change on flow regime and fish habitat in mountain rivers of the south-western Balkans. , 2016, The Science of the total environment.

[32]  M. Acreman.  Environmental flows—basics for novices , 2016 .

[33]  M. Leclerc,et al.  Two‐Dimensional Hydrodynamic Modeling: A Neglected Tool in the Instream Flow Incremental Methodology , 1995 .

[34]  R. Muñoz‐Mas,et al.  Microhabitat competition between Iberian fish species and the endangered Júcar nase (Parachondrostoma arrigonis; Steindachner, 1866) , 2017 .

[35]  Shinji Fukuda,et al.  Revisiting probabilistic neural networks: a comparative study with support vector machines and the microhabitat suitability for the Eastern Iberian chub (Squalius valentinus) , 2018, Ecol. Informatics.

[36]  B. Waters.  A Methodology for Evaluating the Effects of Different Streamflows on Salmonid Habitat , 1976 .

[37]  R. Tharme.  A global perspective on environmental flow assessment: emerging trends in the development and application of environmental flow methodologies for rivers , 2003 .

[38]  F. Pearce.  WHEN THE RIVERS RUN DRY - What happens when our water runs out? , 2006 .

[39]  R. Naiman,et al.  The challenge of providing environmental flow rules to sustain river ecosystems. , 2006, Ecological applications : a publication of the Ecological Society of America.

[40]  Andrew J. H. Davey,et al.  A Comparison of Composite Habitat Suitability Indices and Generalized Additive Models of Invertebrate Abundance and Fish Presence–Habitat Availability , 2007 .

[41]  S. Lek,et al.  Is scuba sampling a relevant method to study fish microhabitat in lakes? Examples and comparisons for three European species , 2001 .

[42]  Ruonan Li,et al.  Determination of an appropriate ecological hydrograph for a rare fish species using an improved fish habitat suitability model introducing landscape ecology index , 2015 .

[43]  J. Holden,et al.  The storage and aging of continental runoff in large reservoir systems of the world , 1997 .

[44]  E. J. Olaya-Marín,et al.  Modelling critical factors affecting the distribution of the vulnerable endemic Eastern Iberian barbel (Luciobarbus guiraonis) in Mediterranean rivers , 2015 .

[45]  B. De Baets,et al.  Abundance versus presence/absence data for modelling fish habitat preference with a genetic Takagi–Sugeno fuzzy system , 2012, Environmental Monitoring and Assessment.