Assessment of Selective Withdrawal and Inflow Control on the Hydrodynamics and Water Quality of Ilam Reservoir

Dehbalaei, Fereshteh Nourmohammadi; Javan, Mitra

doi:10.2175/106143017x15131012152834

Cited by 5 publications

(2 citation statements)

References 15 publications

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“…It has been used to affect biogeochemical cycling (Weber et al, 2017) or to control vertical heat exchange (Mi et al, 2020b). Previous studies have illustrated that selective withdrawal can redistribute the dissolved oxygen in the water column (Carr et al, 2019), decrease nutrient concentrations (Dehbalaei and Javan, 2018), and change the dominant algal assemblages (Rigosi and Rueda, 2012). This body of research indicates that selective water withdrawal may also have potential to control P. rubescens blooms but this has never been explored so far.…”

Section: Introductionmentioning

confidence: 99%

Controlling blooms of Planktothrix rubescens by optimized metalimnetic water withdrawal: a modelling study on adaptive reservoir operation

Hamilton

Frassl

et al. 2022

Preprint

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Background: Aggregations of cyanobacteria in lakes and reservoirs are commonly associated with surface blooms, but may also occur in the metalimnion as subsurface or deep chlorophyll maxima. Metalimnetic cyanobacteria blooms are of great concern when potentially toxic species, such as Planktothrix rubescens, are involved. Metalimnetic blooms of P. rubescens have apparently increased in frequency and severity in recent years, so there is a strong need to identify reservoir management options to control it. We hypothesized that P. rubescens blooms in reservoirs can be suppressed using selective withdrawal to maximize its export from the reservoir. We also expect that altering the light climate can affect the dynamics of this species. We tested our hypothesis in Rappbode Reservoir (the largest drinking water reservoir in Germany) by establishing a series of withdrawal and light scenarios based on a calibrated water quality model (CE-QUAL-W2). Results: The novel withdrawal strategy, in which water is withdrawn from a certain depth below the surface within the metalimnion instead of at a fixed elevation relative to the dam wall, significantly reduced P. rubescens biomass in the reservoir. According to the simulation results, we defined an optimal withdrawal volume to control P. rubescens blooms in the reservoir as approximately 10 million m3 (10% of the reservoir volume) during its bloom phase. The results also illustrated that P. rubescens growth can be most effectively suppressed if the metalimnetic withdrawal is applied in the early stage of its rapid growth, i.e., before the bloom occurs. Additionally, our study showed that P. rubescens biomass gradually decreased with increasing light extinction and nearly disappeared when the extinction coefficient exceeded 0.55 m-1. Conclusion: Our study indicates the rise in P. rubescens biomass can be effectively offset by selective withdrawal strategy and controlling light intensity beneath the water surface. Considering the widespread occurrence of P. rubescens in stratified lakes and reservoirs worldwide, we believe the results will be helpful for scientists and water managers working on other water bodies to minimize the negative impacts of this harmful algae.

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Section: Introductionmentioning

confidence: 99%

Controlling blooms of Planktothrix rubescens by optimized metalimnetic water withdrawal: a modelling study on adaptive reservoir operation

Hamilton

Frassl

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…It has been used to affect biogeochemical cycling [66] or to control vertical heat exchange [40]. Previous studies have illustrated that selective withdrawal can redistribute the dissolved oxygen in the water column [5], decrease nutrient concentrations [11], and change the dominant algal assemblages [55]. This body of research indicates that selective water withdrawal may also have potential to control P. rubescens blooms but this has never been explored so far.…”

Section: Introductionmentioning

confidence: 99%

Controlling blooms of Planktothrix rubescens by optimized metalimnetic water withdrawal: a modelling study on adaptive reservoir operation

Hamilton

Frassl

et al. 2022

Environ Sci Eur

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Background Aggregations of cyanobacteria in lakes and reservoirs are commonly associated with surface blooms, but may also occur in the metalimnion as subsurface or deep chlorophyll maxima. Metalimnetic cyanobacteria blooms are of great concern when potentially toxic species, such as Planktothrix rubescens, are involved. Metalimnetic blooms of P. rubescens have apparently increased in frequency and severity in recent years, so there is a strong need to identify reservoir management options to control it. We hypothesized that P. rubescens blooms in reservoirs can be suppressed using selective withdrawal to maximize its export from the reservoir. We also expect that altering the light climate can affect the dynamics of this species. We tested our hypothesis in Rappbode Reservoir (the largest drinking water reservoir in Germany) by establishing a series of withdrawal and light scenarios based on a calibrated water quality model (CE-QUAL-W2). Results The novel withdrawal strategy, in which water is withdrawn from a certain depth below the surface within the metalimnion instead of at a fixed elevation relative to the dam wall, significantly reduced P. rubescens biomass in the reservoir. According to the simulation results, we defined an optimal withdrawal volume to control P. rubescens blooms in the reservoir as approximately 10 million m3 (10% of the reservoir volume) during its bloom phase. The results also illustrated that P. rubescens growth can be most effectively suppressed if the metalimnetic withdrawal is applied in the early stage of its rapid growth, i.e., before the bloom occurs. In addition, our study showed that P. rubescens biomass gradually decreased with increasing light extinction and nearly disappeared when the extinction coefficient exceeded 0.55 m−1. Conclusions Our study indicates the rise in P. rubescens biomass can be effectively offset by selective withdrawal as well as by reducing light intensity beneath the water surface. Considering the widespread occurrence of P. rubescens in stratified lakes and reservoirs worldwide, we believe the results will be helpful for scientists and managers working on other water bodies to minimize the negative impacts of this harmful cyanobacteria. Our model may serve as a transferable tool to explore local dynamics in other standing waters.

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Key hydrodynamic principles for controlling algal blooms using emergency reservoir operation strategies

Song

You²,

Chen

et al. 2023

Journal of Environmental Management

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Assessment of Selective Withdrawal and Inflow Control on the Hydrodynamics and Water Quality of Ilam Reservoir

Cited by 5 publications

References 15 publications

Controlling blooms of Planktothrix rubescens by optimized metalimnetic water withdrawal: a modelling study on adaptive reservoir operation

Controlling blooms of Planktothrix rubescens by optimized metalimnetic water withdrawal: a modelling study on adaptive reservoir operation

Controlling blooms of Planktothrix rubescens by optimized metalimnetic water withdrawal: a modelling study on adaptive reservoir operation

Key hydrodynamic principles for controlling algal blooms using emergency reservoir operation strategies

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