Comparative assessment of environmental flow using hydrological methods of low flow indexes, Smakhtin, Tennant and flow duration curve

Karimi, Saman; Salarijazi, Meysam; Ghorbani, Khalil; Heydari, Mohammad

doi:10.1007/s11600-021-00539-z

Cited by 30 publications

(9 citation statements)

References 32 publications

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“…In addition, with the common methods implemented, including the traditional Tennant method, basic environmental flows of constant value within the year are obtained, lacking monthly variation. Therefore, for the basic environmental flow calculation, the improved monthly Tennant method [ 25 ] and the dynamic calculation method (DC) [ 44 ], which is widely used in China and recommended by the Chinese National Standard (SL/T 712-2021), were chosen for comparison with the T-FDC proposed in this paper. The improved monthly Tennant method was selected for comparison for the optimal environmental flow calculation.…”

Section: Resultsmentioning

confidence: 99%

“…In addition, the basis of ecological status grading is a fixed percentage, which lacks physical connotation. The methods’ poor spatial transferability and vulnerability to extreme flow events are also issues that need to be solved [ 16 , 24 , 25 ]. Given these shortcomings of hydrological methods, many scholars proposed improvement strategies from three aspects: characteristic flow, calculation period, and percentage coefficient.…”

Section: Introductionmentioning

confidence: 99%

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A Practical Approach for Environmental Flow Calculation to Support Ecosystem Management in Wujiang River, China

Dong

Xie

et al. 2022

IJERPH

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To promote ecosystem protection in the Wujiang River, this paper proposes a practical approach for calculating the environmental flow. The proposed approach combines the idea of the “guarantee rate” of the flow duration curve (FDC) method and the grading idea of the Tennant method. A daily flow series of the Wujiang River was compiled from 1956 to 2019 and used to compare the effect of the proposed approach versus the traditional approaches in four selected sections along the river. The results show that the environmental flow of the Wujiang River can be divided into five levels by the T-FDC method, with a level-by-level disparity, and all levels can capture the temporal and spatial variability of river flow. Additionally, the calculated basic environmental flow process ranges between the historical minimum and second minimum monthly average flow, and the threshold width of the optimal flow is more reasonable than the Tennant method. The T-FDC method can provide technical support for Wujiang River ecosystem management and sustainable development.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Practical Approach for Environmental Flow Calculation to Support Ecosystem Management in Wujiang River, China

Dong

Xie

et al. 2022

IJERPH

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“…The purpose of this section is to highlight the studies on the assessment of the environmental ow, especially comparing different results of the Tenant's method. According to Karimi et al (2021), the assessment of environmental ow using hydrological methods of low ow indexes, Smakhtin, Tennant, and ow duration curve compared. Investigating the results of this study shows that the time pattern of the results should be analyzed in comparison with the observational ow pattern to estimate the environmental ow with a hydrological approach.…”

Section: Literature Reviewmentioning

confidence: 99%

Modification and Development of the Tenant Method to Maintain Ecological Regime in Environmental Flow Management of Rivers

Khatar

Shokoohi

2023

Preprint

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The allocation of environmental flows should be done through legislation based on fundamental studies, while this does not seem to be the case in Iran, and the Tenant method for determining river water rights without assessment has been dictated to the responsible organizations. The main problem of the Tenant method is the allocation of a fixed amount to the environmental flow as a percentage of the average annual flow and therefore the inability to comply with the ecological regime of the river. The main reason for the attention of the country's water authorities to the Tenant method is that in this method as a hydrological method, the long-term average flow in the river is used, which is firstly easily available and secondly does not have to follow the allocation time pattern. In this regard, the responsible agencies can deliver the entire flow allocated to the environment in a volumetric manner over a period of time rather than actual environmental needs. Previous studies have suggested substitute methods concerning the problems of the Tenant method, but in the present study, the promotion of this method has been put on the agenda instead of offering a new method. The substitute methods, which are generally offered by prioritizing the environmental sector in developed countries of the Northern Hemisphere such as the United States, and the Southern Hemisphere such as Australia, are not welcomed in areas facing persistent water shortages and successive droughts. While everyone recognizes that sustainable development has three pillars of economic, social, and environmental justice, and without respect for environmental rights cannot achieve development goals to reach social welfare, the provision of environmental water rights is at the bottom of this circle and has the lowest priority in developing countries. In the present study, due to the importance of the subject and non-admittance of the ecological methods with environmental focus and priority in Iran, the Tenant method was accepted as the only applicable method for allocating environmental flow, then considering the ability and feasibility of Habitat simulation methods changes were made to enhance the Tenant method. In the enhanced Tenant method, instead of considering a fixed value for the whole or half of the year, first using the flow duration curve, the hydrological condition of the river is determined each month. Then, based on the normal, dry, or wet condition of the desired month, and employing the five Tenant scenarios for the management of the river ecosystem, the environmental flow is determined. Accordingly, the developed method, by allocating a percentage of the average monthly flow, practically follows the historical regime of the river without creating a conflict with the requirements of the existing habitats. The results showed that the algorithm used to develop the Tenant method, in addition to success in a proper simulation of -inter-seasonal changes in the river has been able to reduce the annual volume allocated to the environmental flow in the same range recommended in the conventional Tenant method, i.e. within the acceptable range in the opinion of the government.

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“…Tennant (1976) suggested that 10% of the mean annual flow (MAF) must be allocated to maintain the river flow, below which the river will be declared an unsuitable environment for thriving. It is one of the widely used methodologies for estimating environmental flow requirements because of its ease of application (Karimi et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Impact of interbasin transfer hydroelectric project on downstream aquatic habitat

Devi,

Sarma

2023

Ecohydrology

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The recent surge of anthropogenic activities like damming is causing a severe threat to the aquatic ecosystem. A scope of minimizing the degradation of biota exists by modifying the dam operation policy. This can be achieved by releasing a minimum environmental flow (EF), which further requires more scientific investigations. The present study investigated the impact of an interbasin transfer hydropower dam on the downstream habitat of an endangered fish species, Tor putitora, using an adaptive modelling framework. The framework consists of coupling a reservoir operation and a hydrodynamic model. This study analyses the scope of releasing different EFs from a hydropower dam to meet the environmental flow requirement (EFR) at downstream with satisfactory power production efficiency. The EFR was estimated using flow duration curve and Tennant's method. A lean period inflow hydrograph was incorporated into the model with a series of alternate EFs. Two scenarios were explored, with 4 and 6 h of peaking hours, along with the three cases of different initial reservoir storage. The total usable area over the river reach of the mentioned fish species was evaluated from the flow parameters simulated by the hydrodynamic component of the model. The power production efficiencies and area utilization rates were assessed in all these cases to prepare an easy‐to‐use decision support tool in a tabular form depicting the possible states of EF. The generalized methodology adopted in this analysis will help the decision‐makers quantify EF to be released from the dam within an acceptable power generation efficiency.

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Comparative assessment of environmental flow using hydrological methods of low flow indexes, Smakhtin, Tennant and flow duration curve

Cited by 30 publications

References 32 publications

A Practical Approach for Environmental Flow Calculation to Support Ecosystem Management in Wujiang River, China

A Practical Approach for Environmental Flow Calculation to Support Ecosystem Management in Wujiang River, China

Modification and Development of the Tenant Method to Maintain Ecological Regime in Environmental Flow Management of Rivers

Impact of interbasin transfer hydroelectric project on downstream aquatic habitat

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