Environmental Flow Regimes Research Articles

Strategy for Adapting Environmental Flow Proposals to Situations with High Agricultural Demands

Managing water in catchments with high agricultural demands, particularly during periods of low natural flows, is a challenging task. Environmental flow regimes, which are based on monthly minimum values, may not be adequate to address issues associated with rivers that have complex hydrological alteration patterns. The technical solution that provides values to create a flow regime can often be impractical for addressing large problems that planners need to solve, especially when demands are high and resources are limited. This work proposes a new approach to the problem by recognising established agricultural uses and demands that reduce river flow. The focus is on reducing the changes in the hydrological regime by proposing an alternative environmental flow regime that is compatible with agriculture. Deviation from the natural flow of these rivers has been minimized through various processes. Initially, this was achieved by reducing irrigation flows through more efficient demand calculations. The results provide solutions for various hydrological alteration problems, in three rivers, Riaza, Duratón, and Eresma; the inverted regime was corrected, in Cega, Tormes, and Adaja, whose main problem was the reduction of peak flows; controlled peak flows that are compatible with the available water and demands are proposed; and finally in the Agueda river, the reduction in monthly flows was increased on a monthly basis. A new strategy is proposed for considering environmental aspects in the management of rivers with high demands, which improves the fixed schemes for determining environmental flows used in Mediterranean basins.

Long‐term environmental flows restore benthic invertebrate communities in a highly regulated river

The construction of dams and other in‐stream structures for human use has altered river ecosystems worldwide. Dams degrade rivers, and environmental flow releases aim to mitigate flow alterations and restore rivers downstream of dams by returning elements of the pre‐regulation flow regime, resulting in an ecosystem that resembles a more natural state. We examined the responses of benthic invertebrate communities in riffles and pool‐edge habitats to an environmental flow regime (EFR) in the highly regulated Snowy River over 17 years (2000–2016). Benthic invertebrate communities significantly changed in response to prolonged increases in the magnitude of all components of the flow regime. The composition of the benthos in the regulated river became more dissimilar to pre‐EFR communities and more closely resembled those of nearby unregulated rivers. These changes were apparent in both riffle and pool‐edge habitats and were most pronounced when flow magnitudes were highest. Scrapers increased as flows increased, and in contrast, the relative abundances of gatherers declined with prolonged high flows and could be attributed to increased daily flows and high flow events mobilizing fine sediment and scouring benthic substrates. These results indicated that the EFR altered abiotic conditions or resources that previously limited invertebrate abundances, facilitating changes to the benthic community. Community changes we observed were in response to a flow regime that remained drastically lower than natural, demonstrating that restoration targets can be achieved with small flow increases that mimic natural flow patterns.

A fish biodiversity protection based approach for assessing environmental flow regime in rivers

Available environmental flow assessment methods are not able to integrate the impacts of flow regime on the fish biodiversity which means improving these methods is necessary. This study proposes a novel approach to assess environmental flow regime in which the fish biodiversity index is simulated in the structure of the environmental flow assessment for protecting the fish biodiversity values in the case study. Due to considerable impact of water quality parameters as well as physical flow parameters, two combined physical flow and water quality indices were considered as the inputs of simulating fish biodiversity index. Adaptive neuro fuzzy inference system (ANFIS) as well as hydraulic simulation were applied to simulate combined indices of physical flow and water quality. Moreover, a multiple linear regression (MLR) model was utilized for simulating the fish biodiversity index. Due to necessity of simulating natural flow regime in the representative river reach, soil and water assessment tool as a known hydrological tool was applied as well. According to evaluation indices of the case study, ANFIS model as well as SWAT and MLR are reliable to assess environmental flow considering the fish biodiversity. The minimum environmental flow in the study area was assessed 40% of mean annual flow in which the difference between fish biodiversity index between the natural flow and environmental flow is less than 10%. However, significant improvement of water quality is a prerequisite before implementing the proposed environmental flow regime. High computational complexities is one of the weaknesses of the proposed method.

Setting an environmental flow regime under climate change in a data-limited Mediterranean basin with temporary river

Study regionCatchment in Southern Italy. Study focusMediterranean waterways are commonly non-perennial; they are vulnerable to climate change (CC). Their management is particularly complex due to limited data availability. This work aims to develop a methodology for setting an Environmental Flow regime (E-Flows) for a temporary river (Locone, Italy) under limited data availability and under CC. As observed long-term time series of streamflow under natural conditions were not available, the Soil and Water Assessment Tool model (SWAT+) was applied to simulate the daily streamflow for the baseline period (1980–2010) and future (2020–2050) based on observed and model climate projections, respectively. A specific workflow was developed for model calibration focusing on the low flows. The hydrological regime was characterized by means of Indicators of Hydrological Alteration (IHAs), whereas the Range of Variability Approach (RVA) was applied to define the E-Flows. New hydrological insights for the regionThe basin is experiencing a statistically significant increase in the air temperatures observed from 1971 to 2020, which is also predicted to continue in the future. Consequently, the average annual streamflow and monthly streamflow in winter and spring is expected to decrease. The calibration, based on a multi-objective model evaluation, improved the low-flow simulation. The detected differences in IHAs for the predicted periods should be considered in future water management when setting E-Flows for temporary rivers.

Development of an integrated modelling framework to evaluate impacts of pressures on habitat conditions and riverine biota

AbstractIt is becoming extremely challenging to protect the structural and functional integrity of freshwater ecosystems, as many ecological systems face pressures from climate change, population growth and other environmental impacts. However, existing approaches of assessing impacts of external stressors to habitat conditions often neglect the long‐term hydrological changes. This study aimed to develop an integrated modelling framework to assess impacts of different stressors on reach‐scale habitat conditions for benthic macroinvertebrates in a temperate lowland river in central Poland. We coupled hydrological (SWAT+), hydraulic (HEC‐RAS 1D and SRH‐2D) and habitat (CASiMiR) models to predict the response of habitat suitability for the functional group of filter feeders to changes in the catchment for a 135‐m section of the Jeziorka river. Setting up and calibrating individual models required extensive field data collection (e.g., bathymetry field surveys, gauging water levels, discharge and flow velocity measurements and biological sampling). The performance of individual models in simulating discharge, water levels and depth/flow velocity was assessed as satisfactory according to literature. The modelling chain was then applied to compare the effects of three flow scenarios (average, low and high flows). The results showed an overall high value of hydraulic habitat suitability index for filter feeders, with moderately and severely lower values for low and high flow scenario, respectively. The implemented modelling framework performed well could be applied to examine the impacts of climate change and other anthropogenic stressors on reach‐scale habitat conditions. Its practical implementation could be beneficial towards sustainable water resources and environmental flow regime development.

Quantifying the trade-offs in re-operating dams for the environment in the Lower Volta River

Abstract. The construction of the Akosombo and Kpong dams in the Lower Volta River basin in Ghana changed the downstream riverine ecosystem and affected the lives of downstream communities, particularly those who lost their traditional livelihoods. In contrast to the costs borne by those in the vicinity of the river, Ghana has enjoyed vast economic benefits from the affordable hydropower, irrigation schemes and lake tourism that developed after construction of the dams. Herein lies the challenge; there exists a trade-off between water for river ecosystems and related services on the one hand and anthropogenic water demands such as hydropower or irrigation on the other. In this study, an Evolutionary Multi-Objective Direct Policy Search (EMODPS) is used to explore the multi-sectoral trade-offs that exist in the Lower Volta River basin. Three environmental flows, previously determined for the Lower Volta, are incorporated separately as environmental objectives. The results highlight the dominance of hydropower production in the Lower Volta but show that there is room for providing environmental flows under current climatic and water use conditions if the firm energy requirement from Akosombo Dam reduces by 12 % to 38 % depending on the environmental flow regime that is implemented. There is uncertainty in climate change effects on runoff in this region; however multiple scenarios are investigated. It is found that climate change leading to increased annual inflows to the Akosombo Dam reduces the trade-off between hydropower and the environment as this scenario makes more water available for users. Furthermore, climate change resulting in decreased annual inflows provides the opportunity to strategically provide dry-season environmental flows, that is, reduce flows sufficiently to meet low flow requirements for key ecosystem services such as the clam fishery. This study not only highlights the challenges in balancing anthropogenic water demands and environmental considerations in managing existing dams but also identifies opportunities for compromise in the Lower Volta River.

Riparian cottonwood mortality following compound impacts from river water withdrawal and hydroclimatic variation

AbstractOriginating in Glacier Park, Montana, the transboundary St. Mary River has provided a focus for international water sharing for a century. It was dammed and diverted in the USA, and more extensively in Alberta, where it supports Canada's centre for agricultural irrigation. Following water withdrawals, the riparian cottonwoods (Populus angustifolia) collapsed, and we assessed the woodland decline downstream from the St. Mary Dam, through eight sets of aerial photographs over seven decades. These revealed 88% woodland loss from 1951 to 1999 (R2 = 0.984), including a steeper decline with the 1980s drought. Following the implementation of an environmental flow regime that increased minimum flows after 1993, the remnant woodlands were stabilized, with a slight recovery by 2022. Analyses of the historical hydrology revealed compound contributions to the woodland mortality. (1) Annual river flows declined with increasing water diversion, and (2) late summer flows were particularly depleted. (3) Dam operations resulted in abrupt stage recessions and irregular spikes. (4) Accompanying climate warming, the spring snowmelt advanced and late summer flows declined. (5) The greatest climatic influence involved multiple‐year clusters with high versus low flows, corresponding with the Pacific decadal oscillation (PDO) from 1920 to 1990 (R2 = 0.365), but less coupled thereafter. This long‐term study demonstrates the coordination between hydroclimatic variation, water management and the fate of riparian woodlands, which reveal ecosystem health. An environmental flow regime provided benefit, and for other regulated rivers in dry ecoregions, we recommend functional flow regimes that provide sufficient minimum flows and avoid abrupt flow recession or irregular spikes.

Setting an ecological flow regime in a Mediterranean basin with limited data availability: The Locone River case study (S-E Italy)

The Environmental Flow regime (E-Flows) was defined as the flow regime necessary to support river ecosystems, which in turn support crops, the economy, sustainable livelihoods, and human well-being. Although a large number of methods for setting an E-Flow regime have been developed, E-Flows science is still an emerging discipline in non-perennial rivers because of the lack of specific guidelines at the European and national level and the limited data availability (i.e., hydrological/biological). The aim of the present work was to define a methodology for setting an E-Flow regime in a region with limited data availability. The proposed approach was tested in the Locone basin (S Italy). A long time series (1971 to 2020) of daily streamflow in un-impacted conditions were simulated by using the SWAT+ model, a new release of the Soil and Water Assessment Tool. The flow regime was characterized in un-impacted conditions by means of the Indicators of Hydrological Alterations (IHAs) based on modeled daily streamflow. The E-Flow regime was defined by adopting the Range of Variability Approach and assuming the interquartile range (25th - 75th percentile) as an acceptable range of variation of each IHA. For the Locone reservoir, the monthly water release pattern, magnitude, and duration of high and low flow were defined as well as the timing and frequency of floods, and dry conditions.

A comparative analysis of methods for establishing environmental flows in a Mediterranean watershed: suggestions for management

Abstract In Spain, the largest inter-basin transfer is between the Tagus and Segura Basins. This transfer affects the regimes of the Mundo River, a tributary, and the Segura River. In this study, we examine two methodologies for the calculation of environmental flow regimes for the stretches affected by this alteration. When several methodologies are used to determine environmental flows, difficulty arises in deciding which values to propose to restore the river system hydrologically. This work tries to overcome this problem because we present a proposal to make them complementary. As a method for establishing the validity of minimum flow results, a simulation has been carried out on the river section, which has made it possible to evaluate the habitat created and the possibility of fauna movement. The results obtained by the habitat simulation method exceeded those obtained by hydrological methods in terms of habitat creation and hydraulic conditions for connectivity. These same tests have been used to assess the minimum official proposal made by the water administration.

Impact Analysis of Conservation Structures and Climate Change on Streamflow of Thuthapuzha Watershed, Kerala

Hydrological models are increasingly being used to assess how climate change and watershed management practices affect the hydrological processes. In this research, SWAT model was used to analyse the impact of water conservation structures and climate change on streamflow of Thuthapuzha watershed, subbasin of Bharathapuzha located in Kerala, India. Major conservation practices in the study area were modelled as ponds and Kanjirapuzha reservoir was modelled as dam. The impact of conservation structures on streamflow was evaluated and found that monthly streamflow increased during summer season (9-17%), during which usually the river has a lean flow. Thus, the conservation structures increase recharging and thereby helps in maintaining a better environmental flow regime. Similarly, the impact of climate change on streamflow was also analysed and the results of the future simulations of streamflow reveal that, river flow increased under all Representative Concentration Pathways (RCP) scenarios with predominant increase in RCP6 scenario (37-60%) followed by RCP4.5 (13-16%) and RCP8.5 (9-16%) from 2021-2070. For all the scenarios used in the study, due to the predicted increase in rainfall during all the three scenarios, a significant increase in streamflow was observed near the end periods of simulation.

Comprehensive Methodology and Analysis to Determine the Environmental Flow Regime in the Temporary Stream “La Yerbabuena” in Aguascalientes, Mexico

In this study, a comprehensive methodology was adapted to determine the environmental flow regime of “La Yerbabuena”, a temporary stream located in the Aguascalientes Valley, Mexico. The analysis was divided into four stages: the geomorphological watershed analysis, a hydrologic analysis, hydraulic modeling, and environmental analysis. The main geomorphological features of the study area were defined from maps in the spatial block, and with them, a synthetic series of daily and monthly discharge was determined and further used in the next stages. In the hydrological stage, the IHA (Indicators of Hydrologic Alteration) methodology and the procedures from the Mexican regulation, named NMX-159, were applied to the stream, and their results were comparatively analyzed. A similar interannual flow variation from both methodologies was found for wet and dry seasons, ranging from 0.010 to 0.108 m3/s. In the hydraulic modeling stage, a micro-basin part of the stream was modeled in the software HEC RAS, observing that the IHA methodology results had water levels that matched the baseflow of the stream, which allows understanding the hydraulic behavior of the water flow through the generation of different profiles in function of the rainy season. Finally, for the environmental stage, the hydrological health of the stream was evaluated using the software Flow Health, additionally observing that the IHA methodology was closer to the desired water level of the reference. This study demonstrates that the proposed methodology achieves the objectives defined by the NMX-159, which establishes a streamflow regime considering a natural interval of hydrologic variability in both ordinary and after-disturbance conditions. This application of the methodology for temporary streams provides an understanding of the hydrological behavior of the environmental flow throughout the year, and regarding the existing regulations, it presents a correlation with the obtained results, as well as greater precision in the dry season.

Optimizing agricultural cropping patterns under irrigation water use restrictions due to environmental flow requirements and climate change

This study proposes a reservoir operation optimization framework to maximize the regional agricultural profit under the constraints of downstream environmental flow requirements and climate change. Three climate change models—CanESM2, MIROC5, and NorESM1-M—and the soil and water assessment tool (SWAT) were used to simulate the reservoir inflow in future periods under uncertainty. Minimum and ideal environmental flow regimes were embedded in the structure of the reservoir operation model to optimize the environmental flow needs and water supply and assess their tradeoffs. Cropping pattern optimization was used to maximize farmer profit. Particle swarm optimization was applied in the optimization processes. The method was applied to a case study in the Tajan River basin, Iran, with the results showing the environmental flow regime considerably reduces irrigation supply and has significant impacts on farmer profits. The results showed that cropping pattern optimization was not an effective strategy to mitigate the economic impacts of climate change under environmental flow constraints, but this assessment may not be generalized to other areas. Uncertainties related to the climate change models are a notable weakness of the approach and should be considered in future studies.

Enhancing the functionality of environmental flows through an understanding of biophysical processes in the riverine landscape

While water resource managers and river scientists recognize the inherent interconnections among hydrology, river structure, biophysical processes and ecological patterns, management of environmental flows still pays insufficient attention to the ecological and geomorphological functionality of particular aspects of the flow regime. Implementation of more natural flow regimes has improved habitat conditions for native species in many moderately impaired rivers but mimicking a natural flow regime in heavily modified riverine landscapes cannot be expected to yield successful ecological outcomes unless such flows trigger functional processes. For example, the restoration of peak flows may not regenerate habitats if the river is starved of sediment or if the river channel is highly confined. High biodiversity is supported when variable flow regimes interact with spatially variable (heterogeneous) river channel and floodplain forms. In contrast, as rivers become homogeneous, biodiversity decreases when these dynamic spatiotemporal interactions are limited by flow alterations, blocked by channel levees, or perturbed by sediment deficit or surplus. Thus, the design of a more natural environmental flow regime without consideration of the implications for sediment transport and implicit recognition of channel–floodplain geomorphology is likely to have limited success in river management and restoration. To enhance the functionality of environmental flows, considerations of physical, biogeochemical, and ecological processes and the inherent heterogeneity of the riverine landscape must be included. A Functional Flows approach enhances the benefits from limited environmental flow allocations by focusing on the ecological and geomorphological functionality of particular aspects of the flow regime, considering geomorphic context, and emphasizing spatiotemporal diversity at key locations in the riverscape, such as adjacent floodplains or tributary junctions. In this paper, we outline and illustrate the concept of Functional Flows using a flow-chain model and provide two case study examples from Australia and the United States, where improvements in channel habitat and reconnection with the floodplain help to achieve the desired functionality of environmental flows.

Does drifting passage need to be linked to fish habitat assessment? Assessing environmental flow for multiple fish species with different spawning patterns with a framework integrating habitat connectivity

The use of environmental flow (e-flow) regimes has been widely implemented to improve fish habitat quality in river restoration efforts. However, e-flow designs focusing only on one key life stage (e.g., spawning) without considering potential bottlenecks in other stages (e.g., hatching) can result in little to no improvement, especially when targeting the restoration of fish with drifting eggs. Few e-flow assessments are available that closely link the spatial–temporal dependence of the hydrodynamic effect of drifting eggs on hatching habitats. Moreover, an understanding of how to allocate e-flows to achieve the best possible outcomes for biological diversity conservation is still lacking. In this study, a new framework was developed to assess e-flows, aiming to satisfy the requirements of multiple fish species with different spawning patterns concerning streamflow requirements during spawning and hatching periods. In this framework, the final weighted usable area (FWUA) was proposed by linking the spawning demand to the hydrodynamic effect of drifting eggs to assess habitat quality for fish that produce drifting eggs, and water temperature was used to guide when and how to shift from fixed to moving protection targets in allocating e-flows. Here, we used the Xiangjiaba Reservoir, located in the lower Jinsha River, as a case study to design e-flows for the conservation of multiple fish species with different spawning patterns, which was beneficial for increasing the probability of restoration success. By testing scenarios with an absence of drifting passage, the ecological base flow considering only spawning habitat appears to be lower than that considering both quality of spawning habitat and hatching passage. The ecological benefits (FWUA) generated from the ecological base flow identified by traditional models represent only 64.91% of our framework and are thus anticipated to have cascading deviant effects on ecological patterns and processes in riverine ecosystems. This underlying difference in FWUA generated due to different ecological base flows determined from traditional models and our framework, however, has been overshadowed in previous research. We highlight that the highest fish population density recovery potential will be reached at only certain ratios for both sets of habitat benefits. This work provides a tool that can help managers evaluate e-flows and compare different river restoration scenarios to protect degraded rivers or develop strategies to build resilience to climate change.

Productivity of riparian Populus forests: Satellite assessment along a prairie river with an environmental flow regime

AbstractIn semiarid regions, the growth and survival of cottonwoods (riparian Populus species) depend on river water supplementing the limited precipitation. Indicators of growth and productivity are needed to assess how altered streamflow regimes on regulated rivers impact cottonwood trees and the riparian forest ecosystems they support. We used satellite imagery from the Landsat program to make historical (1984–2020) assessments of ecosystem productivity in a riparian cottonwood forest along a regulated prairie river in southern Alberta, Canada, with an environmental flow regime that increased the minimum flows implemented in 1993. A version of the near‐infrared reflectance of vegetation scaled with incoming sunlight (NIRvP) was calculated from Landsat images to provide a proxy for primary production. Near‐infrared reflectance of vegetation scaled with incoming sunlight was correlated strongly with gross primary production measurements from eddy covariance and basal area increment measurements from tree ring analyses, supporting its use as a practical proxy. The lowest NIRvP values occurred in drought years with low flows and dry weather during the growing season, while the highest values occurred in wet years with high flows, including floods. Across all years, NIRvP was positively correlated with streamflow and a weather‐driven soil moisture index. This indicated that ecosystem productivity was limited by water supply, which is sourced from river water and local precipitation. Subsequently, cottonwood forests in this region would be vulnerable to drought from declines in streamflow, due to climatic variations or human water withdrawals, and reductions in shallow soil moisture from limited local precipitation. This satellite proxy should be broadly applicable and can provide a diagnostic indicator for assessing riparian forest health and responses to varying weather, changing climate, and streamflow regulation.

Securing the Environmental Water Requirements of Seasonally Ponding Wetlands: Partnering Science and Management through Benefit Sharing

Although environmental flow regime assessments are becoming increasingly holistic, they rarely provoke water managers to enact the adaptive water reallocation mechanisms required to secure environmental water for wetlands. The conditions that cause science-based environmental flow assessments to succeed or fail in informing the management of environmental water requirements remain unclear. To begin to resolve these conditions, we used process tracing to deconstruct the sequence of activities required to manage environmental water in four case studies of seasonally ponding wetlands in Mediterranean and Mesoamerican watersheds. We hypothesized that, when the flexibility and equitability of the socioeconomic system do not match the complexity of the biophysical system, this leads to a failure of managers to integrate scientific guidance in their allocation of environmental water. Diagnostic evidence gathered indicates that science-management partnerships are essential to align institutional flexibility and socioeconomic equitability with the system’s ecohydrological complexity, and thus move from determination to reallocation of environmental water. These results confirm that institutions e.g., river basin organizations need to be supplemented by motivated actors with experience and skill to negotiate allocation and adaptive management of environmental water. These institutional-actor synergies are likely to be especially important in water scarce regions when the need to accommodate extreme hydrological conditions is not met by national governance capacity. We conclude by focusing on benefit sharing as a means to better describe the conditions for successful science-based environmental flow assessments that realize productive efficiency in environmental water allocation i.e., recognition of multiple values for both people and ecosystems.

Optimizing environmental flow regime by integrating river and reservoir ecosystems

Optimizing environmental flow regime by integrating river and reservoir ecosystems

Trends in Streamflow in Relation to Water Retention Structures: A Case Study in Bharathpuzha River Basin, India

Lack of availability of land, water and other natural resources along with climate change has caused a major threat for increasing the agricultural production on par with the increasing population. Bharathapuzha river is considered as the cradle of civilization in Kerala state, India. The river flow is highly affected by increased water use and reduced recharge caused due to increasing population, urbanization and unscientific management practices. Even though, watershed development activities in river basins help in conserving water in the upstream areas for agricultural, domestic and other uses, very few research have been done to understand its effect on the flow regime in the lower reaches. A number of dams, check dams and other conservation structures have been constructed in Bharathapuzha catchment area during the past and hence its effect on the downstream flow need to be studied. The calibrated and validated SWAT model was applied to Bharathapuzha river basin for studying the impact of watershed interventions on the water balance of the area. The simulated monthly streamflow was analyzed during 2007 to 2011 after addition of Water Retention Structures (WRS) @ 0.05%, 0.1% and 0.2% of the land area. The results indicated that even though the total annual flow decreased, the flow during the summer months (baseflow) increased due to the addition of the conservation structures. The increase in river flow was highest during the period January to April when the river had lean flow. It was found that SWAT model can be used as an effective tool to study the impact of water retention structures in a watershed. The conservation structures help to store water in the upper reaches for irrigation and domestic purpose, and at the same time it helps in increasing the summer flow. This helps to maintain a better environmental flow regime. Hence while planning the conservation measures in a watershed so as to meet the demand of the upstream users, care should be taken to avoid the negative impact that can happen in the downstream.

Least-Cost Provision of Ecosystem Services from Water: When, Where, and How Much?

Changes in surface or groundwater management influence water use patterns as well as the economic value and sustainability of all water uses. In water-scarce regions, programs that establish environmental flows usually involve reallocating water from another productive use. Few peer-reviewed papers to date have investigated impacts on system-wide economic performance resulting from environmental flow regimes. This work presents an original approach to address that gap by developing and applying a basin-scale hydroeconomic optimization model of North America’s Middle Rio Grande Basin to explore impacts of environmental pulse flows on the region’s economy and water stocks. The model accounts for surface and groundwater storage, irrigation, urban, recreational, and environmental demands; surface water inflows under various climate scenarios; groundwater pumping and recharge; substitute water prices; crop water use; evaporation; as well as institutional constraints governing water use. Results show that climate change, in the form of highly variable inflows, has an impact on the total and marginal cost of implementing environmental pulse flows, amplified by the conjunctive nature of the system.

Design of optimal environmental flow regime at downstream of multireservoir systems by a coupled SWAT-reservoir operation optimization method

Design of optimal environmental flow regime at downstream of multireservoir systems by a coupled SWAT-reservoir operation optimization method