Improving Indicators of Hydrological Alteration in Regulated and Complex Water Resources Systems: A Case Study in the Duero River Basin

[EN] Assessing the health of hydrological systems is vital for the conservation of river ecosystems. The indicators of hydrologic alteration are among the most widely used parameters. They have been traditionally assessed at the scale of river reaches. However, the use of such indicators at the basin scale is relevant for water resource management since there is an urgent need to meet environmental objectives to mitigate the effects of present and future climatic conditions. This work proposes a methodology to estimate the indicators of hydrological alteration at the basin scale in regulated systems based on simulations with a water allocation model. The methodology is illustrated through a case study in the Iberian Peninsula (the Duero River basin), where different minimum flow scenarios were defined, assessing their effects on both the hydrological alteration and the demand guarantees. The results indicate that it is possible to improve the hydrological status of some subsystems of the basin without affecting the water demand supplies. Thus, the methodology presented in this work will help decision makers to optimize water management while improving the hydrological status of the river basins.This research was funded by the Spanish Research Agency (AEI), grant number PID2019-106322RB-100; AEI/10.13039/501100011033. R.J.B. was partly funded by the Spanish Ministry of Science and Innovation through the research contract IJC2019-038848-I.Pardo-Loaiza, J.; Solera Solera, A.; Bergillos, RJ.; Paredes Arquiola, J.; Andreu Álvarez, J. (2021). Improving Indicators of Hydrological Alteration in Regulated and Complex Water Resources Systems: A Case Study in the Duero River Basin. Water. 13(19):1-18. https://doi.org/10.3390/w13192676118131

When is a hydrological model sufficiently calibrated to depict flow preferences of riverine species?

Riverine species have adapted to their environment, particularly to the hydrological regime. Hydrological models and the knowledge of species preferences are used to predict the impact of hydrological changes on species. Inevitably, hydrological model performance impacts how species are simulated. From the example of macroinvertebrates in a lowland and a mountainous catchment, we investigate the impact of hydrological model performance and the choice of the objective function based on a set of 36 performance metrics for predicting species occurrences. Besides species abundance, we use the simulated community structure for an ecological assessment as applied for the Water Framework Directive. We investigate when a hydrological model is sufficiently calibrated to depict species abundance. For this, we postulate that performance is not sufficient when ecological assessments based on the simulated hydrology are significantly different (analysis of variance, p < .05) from the ecological assessments based on observations. The investigated range of hydrological model performance leads to considerable variability in species abundance in the two catchments. In the mountainous catchment, links between objective functions and the ecological assessment reveal a stronger dependency of the species on the discharge regime. In the lowland catchment, multiple stressors seem to mask the dependence of the species on discharge. The most suitable objective functions to calibrate the model for species assessments are the ones that incorporate hydrological indicators used for the species prediction

Tipología de ríos en el Ecuador : análisis del régimen del caudal

Knowing the hydrological behavior of rivers and their discharge of water flow of water allows establishing a critical baseline for water resources management. In addition, it allows to relate the hydrological regime with the aquatic biodiversity, the ecological processes they mediate and the environmental services they maintain both at a local and regional level. This research seeks to establish a river classification in Ecuador in order to relate it to key ecological processes based on multi-year hydrographs that analyze flow regimes...Conocer el comportamiento hidrológico de los ríos y su caudal de agua permite establecer una línea base para la gestión de los recursos hídricos. Además, permite relacionar el régimen hidrológico con la biodiversidad acuática, los procesos ecológicos que estos median y los servicios ambientales que estos proveen tanto a nivel local como regional. Esta investigación busca establecer una clasificación de ríos en el Ecuador para relacionarla con procesos ecológicos claves en base a hidrogramas multianuales que analizan los regímenes de caudal..

From microhabitat ecohydraulics to an improved management of river catchments: bridging the gap between scales

[EN] Ecohydraulic studies in rivers range from local-scale studies, which target a better understanding of the mechanisms underlying biological responses to microhabitat hydraulics, to large-scale studies, which address the influence of hydro-morphological management on catchment biodiversity. A major challenge in the field is to bridge the gap between local- and large-scale studies, in order to base the large-scale physical management of rivers on general and transferable ecohydraulic processes. This Special Issue includes ten articles that illustrate progresses and difficulties to bridge this gap. It gathers microhabitat-scale studies focused on the identification of major ecohydraulic mechanisms, reach-scale studies that typically target generality and transferability across reaches, and examples of catchment-scale management based on general ecohydrological knowledge. The Special Issue illustrates how ecohydraulics have evolved to better integrate dynamic physical processes, ecological concepts and the consideration of ecosystem services. Although this remains challenging in practice, the Special Issue shows the need to integrate dynamic hydraulic descriptors of the environment for improving the cost-effectiveness of large-scale rivermanagement and restoration. These articles were presented at the 10th International Symposium on Ecohydraulics in Trondheim, Norway (2014), where the first symposium on ecohydraulics was organised 20 years before. The 10th issue of the symposium celebrated 20 years of ecohydraulic research and had about 300 delegates, giving 194 talks and presenting 86 posters.Harby, A.; Martinez-Capel, F.; Lamouroux, N. (2017). From microhabitat ecohydraulics to an improved management of river catchments: bridging the gap between scales. River Research and Applications. 33:189-191. doi:10.1002/rra.3114S18919133Anderson, D., Moggridge, H., Shucksmith, J. D., & Warren, P. H. (2015). Quantifying the Impact of Water Abstraction for Low Head ‘Run of the River’ Hydropower on Localized River Channel Hydraulics and Benthic Macroinvertebrates. River Research and Applications, 33(2), 202-213. doi:10.1002/rra.2992Doyle, M. W., Stanley, E. H., Strayer, D. L., Jacobson, R. B., & Schmidt, J. C. (2005). Effective discharge analysis of ecological processes in streams. Water Resources Research, 41(11). doi:10.1029/2005wr004222Egger, G., Politti, E., Lautsch, E., Benjankar, R. M., & Rood, S. B. (2016). Time and Intensity Weighted Indices of Fluvial Processes: a Case Study from the Kootenai River, USA. River Research and Applications, 33(2), 224-232. doi:10.1002/rra.2997Hailegeorgis, T. T., & Alfredsen, K. (2016). Regional Statistical and Precipitation-Runoff Modelling for Ecological Applications: Prediction of Hourly Streamflow in Regulated Rivers and Ungauged Basins. River Research and Applications, 33(2), 233-248. doi:10.1002/rra.3006Lamouroux, N., Pella, H., Snelder, T. H., Sauquet, E., Lejot, J., & Shankar, U. (2013). Uncertainty Models for Estimates of Physical Characteristics of River Segments Over Large Areas. JAWRA Journal of the American Water Resources Association, 50(1), 1-13. doi:10.1111/jawr.12101Harby, A., Martinez- Capel, F., & Lamouroux, N. (2017). From Microhabitat Ecohydraulics to an Improved Management of River Catchments: Bridging the gap Between Scales. River Research and Applications, 33(2), 189-191. doi:10.1002/rra.3114Martínez-Capel, F., García-López, L., & Beyer, M. (2016). Integrating Hydrological Modelling and Ecosystem Functioning for Environmental Flows in Climate Change Scenarios in the Zambezi River (Zambezi Region, Namibia). River Research and Applications, 33(2), 258-275. doi:10.1002/rra.3058Martínez-Fernández, V., González del Tánago, M., Maroto, J., & García de Jalón, D. (2016). Fluvial Corridor Changes Over Time in Regulated and Non-Regulated Rivers (Upper Esla River, NW Spain). River Research and Applications, 33(2), 214-223. doi:10.1002/rra.3032Mathews, R., & Richter, B. D. (2007). Application of the Indicators of Hydrologic Alteration Software in Environmental Flow Setting1. JAWRA Journal of the American Water Resources Association, 43(6), 1400-1413. doi:10.1111/j.1752-1688.2007.00099.xNoack, M., Ortlepp, J., & Wieprecht, S. (2016). An Approach to Simulate Interstitial Habitat Conditions During the Incubation Phase of Gravel-Spawning Fish. River Research and Applications, 33(2), 192-201. doi:10.1002/rra.3012Nzau Matondo, B., Benitez, J. P., Dierckx, A., Philippart, J. C., & Ovidio, M. (2016). Assessment of the Entering Stock, Migration Dynamics and Fish Pass Fidelity of European Eel in the Belgian Meuse River. River Research and Applications, 33(2), 292-301. doi:10.1002/rra.3034Parasiewicz P Castelli E Rogers J Vezza P Kapusta A 2017 Implementation of the natural flow paradigm to protect dwarf wedgemussel ( Alasmidonta heterodon ) in the upper Delaware River River Research and Applications 33 2 276 290 10.1002/rra.3112Rice, S. P., Little, S., Wood, P. J., Moir, H. J., & Vericat, D. (2010). The relative contributions of ecology and hydraulics to ecohydraulics. River Research and Applications, 26(4), 363-366. doi:10.1002/rra.1369Roy, M. L., Roy, A. G., & Legendre, P. (2010). The relations between ‘standard’ fluvial habitat variables and turbulent flow at multiple scales in morphological units of a gravel-bed river. River Research and Applications, 26(4), 439-455. doi:10.1002/rra.1281Seliger, C., Scheikl, S., Schmutz, S., Schinegger, R., Fleck, S., Neubarth, J., … Muhar, S. (2015). Hy:Con: A Strategic Tool For Balancing Hydropower Development And Conservation Needs. River Research and Applications, 32(7), 1438-1449. doi:10.1002/rra.2985Statzner, B., Gore, J. A., & Resh, V. H. (1988). Hydraulic Stream Ecology: Observed Patterns and Potential Applications. Journal of the North American Benthological Society, 7(4), 307-360. doi:10.2307/1467296Vowles, A. S., Eakins, L. R., Piper, A. T., Kerr, J. R., & Kemp, P. (2013). Developing Realistic Fish Passage Criteria: An Ecohydraulics Approach. Ecohydraulics, 143-156. doi:10.1002/9781118526576.ch

Comparison and Validation of Hydrological E-Flow Methods through Hydrodynamic Modelling

Flow regime determines physical habitat conditions and local biotic configuration. The development of environmental flow guidelines to support the river integrity is becoming a major concern in water resources management. In this study, we analysed two sites located in southern part of Portugal, respectively at Odelouca and Ocreza Rivers, characterised by the Mediterranean climate. Both rivers are almost in pristine condition, not regulated by dams or other diversion construction. This study presents an analysis of the effect on fish habitat suitability by the implementation of different hydrological e-flow methods. To conduct this study we employed certain hydrological e-flow methods recommended by the European Small Hydropower Association (ESHA). River hydrology assessment was based on approximately 30 years of mean daily flow data, provided by the Portuguese Water Information System (SNIRH). The biological data, bathymetry, physical and hydraulic features, and the Habitat Suitability Index for fish species were collected from extensive field works. We followed the Instream Flow Incremental Methodology (IFIM) to assess the flow-habitat relationship taking into account the habitat suitability of different instream flow releases. Initially, we analysed fish habitat suitability based on natural conditions, and we used it as reference condition for other scenarios considering the chosen hydrological e-flow methods. We accomplished the habitat modelling through hydrodynamic analysis by using River-2D model. The same methodology was applied to each scenario by considering as input the e-flows obtained from each of the hydrological method employed in this study. This contribution shows the significance of ecohydrological studies in establishing a foundation for water resources management actions

Factors regulating year‐class strength of Silver Carp throughout the Mississippi River basin

Recruitment of many fish populations is inherently highly variable inter-annually. However, this variability can be synchronous at broad geographic scales due to fish dispersal and climatic conditions. Herein, we investigated recruitment synchrony of Silver Carp Hypophthalmichthys molitrix across the Mississippi River basin. Year-class strength (YCS) and synchrony of nine populations (max linear distance = 806.4 km) was indexed using catch-curve residuals correlated between sites and related to local and regional climatic conditions. Overall, Silver Carp YCS was not synchronous among populations, suggesting local environmental factors are more important determinants of YCS than large-scale environmental factors. Variation in Silver Carp YCS was influenced by river base flow and discharge variability at each site, indicating that extended periods of static local discharge benefit YCS. Further, river discharge and air temperature were correlated and synchronized among sites, but only similarities in river discharge was correlated with Silver Carp population synchrony, indicating that similarities in discharge (i.e., major flood) among sites can positively synchronize Silver Carp YCS. The positive correlation between Silver Carp YCS and river discharge synchrony suggests that regional flood regimes are an important force determining the degree of population synchrony among Mississippi River Silver Carp populations

Impact of human intervention and climate change on natural flow regime

According to the ‘natural flow paradigm’, any departure from the natural flow condition will alter the river ecosystem. River flow regimes have been modified by anthropogenic interventions and climate change is further expected to affect the biotic interactions and the distribution of stream biota by altering streamflow. This study aims to evaluate the hydrologic alteration caused by dam construction and climatic changes in a mesoscale river basin, which is prone to both droughts and monsoonal floods. To analyse the natural flow regime, 15 years of observed streamflow (1950–1965) prior to dam construction is used. Future flow regime is simulated by a calibrated hydrological model Soil and Water Assessment Tool (SWAT), using ensemble of four high resolution (~25 km) Regional Climate Model (RCM) simulations for the near future (2021–2050) based on the SRES A1B scenario. Finally, to quantify the hydrological alterations of different flow characteristics, the Indicators of Hydrological Alteration (IHA) program based on the Range of Variability Approach (RVA) is used. This approach enables the assessment of ecologically sensitive streamflow parameters for the pre- and post-impact periods in the regions where availability of long-term ecological data is a limiting factor. Results indicate that flow variability has been significantly reduced due to dam construction with high flows being absorbed and pre-monsoon low flows being enhanced by the reservoir. Climate change alone may reduce high peak flows while a combination of dam and climate change may significantly reduce variability by affecting both high and low flows, thereby further disrupting the functioning of riverine ecosystems. We find that, in the Kangsabati River basin, influence of dam is greater than that of the climate change, thereby emphasizing the significance of direct human intervention

Integrating hydrological modelling and ecosystem functioning for environmental flows in climate change scenarios in the Zambezi River (Zambezi Region, Namibia)

The Zambezi-Chobe wetlands in Namibia are of great international importance for trans-boundary water management because of their remarkable ecological characteristics and the variety and magnitude of the ecosystem services provided. The main objective of this study is to establish the hydro-ecological baseline for the application of environmental flow regimes (EFR). The specific objectives are: (i) the assessment of environmental flow components (EFC) in the current near-natural hydrological conditions; (ii) the generation of future scenarios for climatic and socioeconomic changes; (iii) the estimation of the area duration curves and estimated annual habitat during the inundation of the critical habitats for fisheries (mulapos), under the existing conditions and future scenarios; and (iv) to provide a framework for the future application of EFRs, based on hydrological and ecological processes. To make a sound analysis of the ecological implications, first we develop a conceptual framework of the linkages between the hydrological and biological processes concerning fish communities, because of the critical role of fisheries in the region. The EFCs in near-natural hydrological conditions provide the basis for developing interim EFRs in the region, within the framework of an adaptive management of water resources. The future scenarios indicate a mitigation of the flow variability; and, in the worst-case scenario, the reduction of the maximum flow and inundated area of the mulapos would result in a reduction of the estimated annual habitat of 22%. This means a reduction in the spawning habitats for quiet-water species, in the food resources for fry and juvenile fish and a consequent reduction in fish stocks. Furthermore, the habitat loss during low events is similar and greater under both scenarios, at ca. 35%. Here we corroborate that the EFCs and their variability may become the building blocks of flow-ecology models that lead to environmental flow recommendations, monitoring and research programmes and flow protection activities.This research was part of the research project CERPA (Certification of Protected Areas), funded by the German Federal Ministry of Education and Research (BMBF), and focused on the evaluation of new market-based instruments for biodiversity conservation and their socioeconomic implications. The authors also thank two anonymous reviewers who provided substantial input that improved the manuscript. The study has been partially funded by the national research project IMPADAPT (CGL2013-48424-C2-1-R), with MINECO (Spanish Ministry of Economy) and FEDER funds.Martinez-Capel, F.; García López, L.; Beyer, M. (2017). Integrating hydrological modelling and ecosystem functioning for environmental flows in climate change scenarios in the Zambezi River (Zambezi Region, Namibia). River Research and Applications. 33(2):258-275. https://doi.org/10.1002/rra.3058S25827533