Sediment management and Ecology in Rivers with reservoirs

Samenvatting project

The construction of dam operating regimes always presents a trade-off between power generation water supply and/or flood protection on the one hand and ecological quality of the reservoir and the river downstream of the dam on the other hand. Sedimentation in reservoirs impacts the reservoir purposes, creates shortages in sediment supply downstream and has implications for river morphology and ecology. The use of sediment management practices such as flushing or sluicing to transport more sediment to the downstream has not been fully investigated with respect to their consequences in improving habitat suitability. However with the expansion of building reservoirs in cascading systems sediment management becomes less effective and costly. The synchronization of sediment management in cascading systems needs to be explored further. To assist managers in selecting the most cost-efficient eco-friendly dam and reservoir management regime knowledge and development of tools to diagnose the challenges and to provide the managers with integrated solutions is needed. Deltares together with Jpower are aiming to improve the knowledge related to ecology and sediment management in rivers with reservoirs. A 2D-model (Delft3D) has been developed and coupled with RTC-tool (Real Time Control Tool) in order to mimic the real time dam operation of a single reservoir. This has been used to optimize the sediment management in the reservoir and the river downstream.

The aim of this project is to further deepen and broaden our knowledge and develop our tools (add-ons or coupling) to be able to link the dam operation with respect to ecology and sediment. This allows an assessment of the ecological and sediment implications of dam and reservoir management scenarios to determine the optimal cost-efficient management strategy for green and sustainable development of rivers systems with reservoirs.

Doel van het project

The aim of this project is to further deepen and broaden our knowledge and develop our tools (add-ons or coupling) to be able to link the dam operation with respect to ecology and sediment to:
1) efficiently flush the reservoirs (to increase their lifetime) in a cascade
2) reduce erosion problems and increase the sediment supply within and downstream of a dam cascade and
3) create a good and sustainable habitat and ecosystem downstream by integrating the habitats requirements in the dam operation.

This allows an assessment of the ecological and sediment implications of dam and reservoir management scenarios to determine the optimal cost-efficient management strategy for green and sustainable development of rivers systems with reservoirs.

Motivatie

The construction of dam operating regimes always presents a trade-off between power generation water supply and/or flood protection on the one hand and ecological quality of the reservoir and the river downstream of the dam on the other hand.Sedimentation in reservoirs decreases their lifespan and has severe impact on the reservoir purposes. The trapping of sediment in reservoirs creates shortages in sediment supply downstream. This has implications for river morphology and creates ecological problems (changing temperatures sediment starvation blocking fish migration altering habitats etc). The shortage of sediment creates different bed characteristics which might not be suitable for fish. The use of sediment management practices such as flushing or sluicing to transport more sediment to the downstream has not been fully investigated with respect to their consequences in improving habitat suitability. However with the expansion of building reservoirs in cascading systems sediment management becomes less effective and costly. The synchronization of sediment management in cascading systems needs to be explored further. To assist managers in selecting the most cost-efficient eco-friendly dam and reservoir management regime knowledge and development of tools to diagnose the challenges and to provide the managers with integrated solutions is needed. Deltares together with Jpower are aiming to improve the knowledge related to ecology and sediment management in rivers with reservoirs. A 2D-model (Delft3D) has been developed and coupled with RTC-tool (Real Time Control Tool) in order to mimic the real time dam operation of a single reservoir. This has been used to optimize the sediment management in the reservoir and the river downstream. However because of the need to synchronize and optimize downstream ecology in combination with sediment management for river with cascading dams it is vital to look for large scale system operation measures that integrate

Locatie

Delft

Uitgevoerde acties

1. Literature survey on ecological implications of reservoir management.
2. Implement new cohesive sediment transport formula in Delft3D and couple it with RTC-tools.
3. 2D-morphodynamic- and water quality modelling of Funagira Reservoir in the Tenryuu River with Delft3D (to simulate different sets of reservoir conditions and gate operations using non-cohesive sediment and cohesive sediment in suspension). Then perform a proper analysis to the data to come up with useful conclusion to be used in reservoirs and dams which have similar challenging conditions. Best Feedback approach from and to HABITAT model will be investigated and recommended
4. Improve the workflow in HABITAT with scripting in Python to i) automatically update and run habitat suitability models for several years using input from Delft3D-models and ii) automatically setup a model structure with pre-defined response curves.
5. Perform habitat suitability modelling using the new developments to assess the ecosystem downstream of Funagira Dam.
6. Perform sediment management in cascading system using 2D modelling approach

Verwachtte resultaten

 HABITAT model application for Funagira reservoir and the river downstream
 Python scripts for improved workflow in HABITAT and including meta-information
 New formula implemented in Delft3D sed-mor module.
 2D morphodynamic and water quality model of Funagira reservoir and downstream reach that can be coupled to habitat model.
 Memorandum with the results of the pilot application for Funagira dam.
 Python scripts will be uploaded to the HABITAT wiki.
 Update to Deltares publicwiki.

Innovativiteit

High-resolution modelling tools such as Delft3D and HABITAT model are still not yet commonly used in the hydropower sector to quantify and mitigate the environmental impacts of dam operation and particularly not for dam cascades. Previous studies (Tenryuu River Mekong River Koshi River etc) show that proper integration of sediment and ecological management measures require dynamic coupling of 2D/3D modelling tool. Existing tools do not provide enough functionality to use them in practice where dam operators base their environmental operations mostly on trial and error. This study will not only increase the capabilities in modelling these conditions but also introduce tools that allow smarter ways to integrate ecological and sediment management to optimize the dam operation. These technologies allow dam operators to adjust the general sediment management strategy while more accurately predicting the environmental consequences (on short and long term).To allow quick ecological calculations of the habitat suitability in order to build the meta-model the workflow in HABITAT will be optimized through Python scripting. For several years now the functionality of Python scripting in HABITAT is available. This is due to generic developments in DeltaShell. Until now this functionality has been largely neglected due to limited knowledge on Python by HABITAT users and the lack of predefined scripts to be used in analyses. However this functionality can be used to automate the model setup create uniformity in response curves and speed up calculations.

Valorisatie

Niet ingevuld

Hoe gaan de participanten van het project om met intellectueel eigendom dat voorkomt uit deze projecten?

Alle partijen krijgen alle resultaten van het Project ter beschikking. De resultaten van de samenwerking kunnen breed verspreid worden. Partijen kunnen over deze resultaten vrijelijk publiceren. De resultaten zullen volledig openbaar beschikbaar zijn, met uitzondering van ter beschikking gestelde achtergrondkennis.

Op welke wijze wordt de informatie over dit project op eenvoudige wijze voor het algemene publiek kenbaar gemaakt (beschrijving van het onderzoek, deelnemers en de planning en voortgang)?

De informatie over dit project wordt kenbaar gemaakt via de website van de TKI Deltatechnologie (projectbeschrijving) en de projectwiki van Deltares (projectvoortgang en resultaten).

Projectvoorwaarden

Na de datum waarop deze Overeenkomst in werking is getreden, maar uiterlijk tot een jaar voor de beoogde datum waarop het Project zal zijn voltooid, kunnen ondernemers en/of onderzoeksinstellingen, die op het terrein van het relevante subsidieprogramma van het TKI werkzaam zijn alsnog als Partij toetreden. Een later toetredende Partij zal een nader overeen te komen bijdrage in kind en/of in cash moeten leveren die in redelijke verhouding staat tot zijn relatief aandeel in het Project na toetreding. De overige Partijen ontvangen vervolgens naar rato een terugbetaling en/ of gedeeltelijke vrijstellingen van hun nog te leveren bijdrage in kind, voor zover niet besloten wordt de bijdrage van de later toetredende Partij aan het projectbudget toe te voegen.

Projecteigenaar en projectleider(s)

Projecteigenaar:
Hans Groot
Er is geen projectleider aan dit project toegekend.

Partners

  • J-Power Chigasaki Research Institute
  • Stichting Deltares (Delft)
  • TKI Deltatechnologie

Resultaten

Sediment management and Ecology in Rivers with reservoirs-2020-3

Resultaat type
Methodes
Aantal
5
Omschrijving

Results
- HABITAT model application for Funagira reservoir and the river downstream

- Python scripts for improved workflow in HABITAT, and including meta-information;

- New formula implemented in Delft3D sed-mor module.

- 2D morphodynamic and water quality model of Funagira reservoir and downstream reach that can be coupled to habitat model.

- Python scripts will be uploaded to the HABITAT wiki.

https://publicwiki.deltares.nl/display/TKIP/DEL080+-+Sediment+management+and+Ecology+in+Rivers+with+reservoirs

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