Development of process-based tools for assessing reservoir sediment management considering river ecosystem
Deltares together with J-Power have been working on improving and applying the knowledge and tools related to sediment management in rivers with reservoirs considering the river basin wide ecosystem. Consequently, this research aims to improve sediment transport processes by implementing spatial and temporal variation of porosity and consolidation with cohesive sediment and implementing this functionality in the Delft3D4 software. Moreover, we propose the coupling between morphology, habitat and RTC tools with the development of a Delft3D - Flexile Mesh model and Delta-Shell platform with new routines that link hydro-morphological processes, dam operations and ecology. These models with new functionality and routines will be tested, validated and applied in case studies in a
Japanese reservoir (Funagira, owned by our collaborator J-Power). The models will also be tested on the river basin scale in a large scale synchronized operation of multiple reservoirs considering both sediment and ecology. The outcome of this research is expected to be resulting in our joint conference/journal papers as well.
Doel van het project
The main aim of this project is to further deepen broaden and integrate our knowledge and improve our tools (add-ons and coupling) to be able to link the dam and sediment management operation with ecology. Followings are some of the aims and objectives of the proposed project:
1) To implement new functionality in our modelling tool to improve the morphological replication and prediction with dam operation that could be more useful to assess river environment and habitats
2) To improve and test our tool to replicate efficient and optimal sluicing and flushing operation of the system of reservoirs in a cascade
3) To improve and integrate our tools (morphology dam operation and ecology) that could be used to address the problems of mitigating negative ecological effects and maintaining sustainable aquatic ecosystems.
4) To apply new developments (like Delft3D-Flexible Mesh and Delta-Shell) and make our tools more user-friendly
This allows quantitative assessment of implications and impacts of dam and reservoir operation and management scenarios on river morphology and ecology. This will help to determine the optimal management strategy for green and sustainable development of river system with reservoirs.
Dams and reservoirs are functional assets of river basins particularly in areas with strong seasonal variations in rainfall-runoff patterns where they can regulate river flow to prevent flooding as well as in areas with ever-growing water and energy demand due to growth of economy and population. However it is obvious that any intervention in a natural system induces adverse impacts on the ecosystem. Additional negative impacts of dams and reservoirs can also be attributed to poor planning mismanagement inefficient operation and improper consideration (or negligence) of impact mitigation options and conditions.The major environmental problem of dams in a river basin is the disturbance in natural flow dynamics and sediment transport for example shortage in downstream flow and sediment supply leading to micro- to large-scale morphological changes and changes in species habitats. These changes do not only impact riverbeds floodplains and settlements but also aquatic and riparian habitats (e.g. wetlands and fish spawning areas) and ecological processes (e.g. fish migration cues). On the other hand the reservoirs themselves suffer from sedimentation problems and one of the main sediment-induced problems is storage loss. Globally the total storage in reservoir is around 7000 km3. Due to sedimentation we lose around 57 billion m3 per year (according to ICOLD 2009). The available water storage per capita is decreases since 1980. This means the solution we have so far is not sustainable.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 in the reservoir and the river system (changing temperatures sediment starvation blocking fish migration altering habitats etc.). The shortage of sediment creates different bed characteristics which might not
Component-1: Research/model improvement/Testing (Fundamental and industrial research)
Task 1.1:Implementing new approach and(a) unctionality for computation of spatial and temporal variation of porosity and consolidation considering cohesive sediment in Delft3D4 software(b) Testing of the new functionality in Delft3D4 morphological model with RTC
Task 1.2:(a) Implementing a routine for exchange of information in Delta-Shell environment for better and user-friendly integration for coupled morphology and habitat modelling(b) Testing of the new implementation to compute relevant ecological statics
Task 1.3:Implementing and testing improved coupling of morphology habitat and Real-Time Control Tool (RTC) in D-FM model
Component-2: Application and validation (Experimental development)
Task 2.1:Application and validation of the new functionality in Delft3D4 morphological model with RTC for a real-world case (Funagira Reservoir in Japan)
Task 2.3:Real-world application of coupled model (morphology + habitat + RTC) in D-FM to Funagira reservoir morphological model with habitat assessment
Task 2.4:Application of the improved model in a cascade system of dams
Process-based modelling tools such as Delft3D Delft3D-Flexible Mesh (D-FM) and HABITAT models are still not yet commonly used in the dam (hydropower multi-purpose) sector to quantify and mitigate the environmental impacts of their operation. 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 processes in a physics based manner but also introduce tools that allow improved and smarter ways to integrate sediment management and ecosystem 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 a short- and long-term).To enable dynamic morphological computation and habitat assessment in Delta Shell the expected development will provide smooth way for quick ecological computations 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 has been available. This is due to generic developments in Delta Shell. 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 computations.
Delft3D4 with new functionality; All model users for further research and applications in projects; Deltares will maintain it by applying in more case studies/ projects and regularly improving it.
Delft3D-FM with Habitat in DeltaShe; All model users for further applications in projects; Deltares will maintain it by
applying in more case studies/ projects and regularly improving it.
Scientific paper and public-wiki; Open to all; Deltares and J-Power can jointly work and improve in future as well
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.
De informatie over dit project wordt kenbaar gemaakt via de website van de TKI Deltatechnologie (projectbeschrijving) en de projectwiki van Deltares (projectvoortgang en resultaten).
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.