DEL114 – 11204510/11204511 Improving an integrated operational tool to manage a river system with dams and reservoirs considering flow, sediment and ecology

Aanleiding van het project

Dam and reservoirs are important for water storage, renewable energy generation as well as flood management, particularly in areas with strong seasonal variations in rainfall-runoff patterns along with ever-growing water and energy demand due to growth of economy and population. However, these dammed reservoirs intervene the natural system of rivers: they distort the natural environmental flow of the river. The natural environmental flow of a river is defined by the quantity, frequency, timing, predictability and duration of a river’s flow regime. Over hundreds of years, this natural flow regime has shaped the riverine functioning in terms of abiotic and biotic interactions. The degree of impact of dams on a river’s natural flow regime depends on the extent of the required water storage, the diversion of the water from the natural river bedding and the interruption of the lateral connectivity.
The major negative impact 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) and therefore socio-economic benefits, like providing food for local communities and profits for larger scale companies. It is vital to improve the ecosystem services of regulated rivers to minimize the hinderance to the natural processes.
Common impacts of changes of the natural environmental flow by river damming are deterioration of the natural riverine habitats as flow and sediment and erosion dynamics changed. Also, damming of rivers introduce the risk of calamity (e.g. dam break). Reservoirs behind dams may introduce emissions, enhance pollution (virtually stagnant water) and health challenges, especia

Doel van het project

The overall objective is to improve our knowledge base and tools to support the optimal management strategy for resilient river system with reservoirs considering large (e.g. catchment level) to detailed scale (e.g. reach level). Followings are some of the objectives of the proposed research activities:
1) To implement new functionalities in our 1D and 2D flexible mesh software to make it usable to provide a reliable prediction of dam operation, flow, sediment transport and ecology (Delft3D-FM+RTC under Delta-Shell platform).
2) To validate above mentioned functionalities in our modelling tools to improve the morphological replication and prediction with dam operation that could be more useful to assess river environment and habitats
3) Provide 1D and 2D modelling tools that are equipped with new functionalities needed for optimal sluicing and flushing operation of the system of reservoirs in a cascade.
4) To provide RTC tool with improved approach (a step ahead) for optimizing reservoir operation by integrating component related to environmental flow, sediment transport and habitat suitability models and tools:
One and two-dimensional models, namely Delft3D4 and Delft3D-FM (1D and 2D), are coupled with RTC tool to mimic the real-time dam operation (standalone and synchronized). The coupling will be improved further in complement with water quality and habitat suitability tools. The tool will be also be improved and used to optimize the water use, environmental releases, sediment management and habitat suitability in an integrated manner.

Omschrijving van de activiteiten

Implementing and testing new sediment transport formula in Delf3D- FM software Fundamental research (1) Deltares
Implementing the PID controller in Delft3D-FM 1D for gate operation as well as validating of the new development (e.g. the new cohesive sediment transport formula) in Delft3D4 morphological model with RTC. Fundamental research (2) Deltares & Jpower
Investigating and improving the implementation of Fluff layer of sediment to replicate deposition and erosion process of fine sediment/mud in reservoirs and downstream reach (relevant for fish) Fundamental research (3) Deltares & Jpower

Activiteit Type activiteit Rol partijen
Implementing and testing an adapter to better connect the HABITAT knowledge database. The adapter will help to read the files and produce HABITAT model ready to run within Delta-Shell. Experimental research (1) Deltares
Testing further application of porosity model (as a part of new sediment transport approach) given that some of the options do not work with ‘mud’ functionality.
Experimental research (2) Deltares & Jpower
Application of the new functionality in Delft3D4 morphological model with RTC for a real-world case (Funagira Reservoir in Japan) Industrial research (1) Jpower & Deltares
Real-world application of coupled model (morphology + habitat + RTC) in Delft3D-FM to Funagira reservoir morphological model with habitat assessment Industrial research (2) Jpower and Deltares
Application of the improved 1D-model in a cascade system of dams in Tenryu River. Industrial research (3) Jpower & Deltares
Optimization of Funagira reservoir operation as standalone optimization using RTC tool Industrial research (4) Jpower & Deltares
Develop knowledge related to species traits (specific characteristics of species) as modelling entity instead of species in Habitat modelling. Industrial research (5) Jpower & Deltares
Investigate how to consider sediment and HABITAT to optimize reservoir operation in RTC-toolbo

Verwachte resultaten

Proposal, inventory and data collection memo 2019
Update of Delft3D-FM code with the new proposed development 2019/2020
Delft3D4/FM model testing and application case with RTC, morphology and habitat suitability assessment 2020
Develop 1D model for the river with the 3 cascade dams including sediment and structures’ control using Delft3D-FM 2020
Optimization of Funagira reservoir operation as a standalone system using RTC tool with optimization 2020
Memorandum with the results and a conference/journal paper will be written (together with J-Power) 2020
Update to Deltares public-wiki. 2020

Innovativiteit

Process-based modelling tools such as Delft3D4, Delft3D-FM and HABITAT models are still not yet commonly used in an integrated manner in dam sector (hydropower, multi-purpose) to quantify and mitigate relevant impacts (hydraulic, morphological and ecological) of their operation. Furthermore, previous TKI-projects in variety of river systems with interventions (Tenryuu River, Mekong River, Koshi River, Marsyangdi River etc.) show that it is more practical to replicate the larger scale processes in a river system with cascade dams by using one-dimensional (1D) approach. 1D model with sediment transport and real-time operation will be a practical tool to replicate large scale system in order to investigate synchronized and optimal behaviour of the system with interventions. This will immensely contribute to reach our goal of providing 1D, 2D and 3D modelling in one coupled model domain and platform. Existing tools do not provide enough functionality, flexibility and robustness to use them in integrated way in practice. Some of the innovative aspects can be outlined as follows:
• Improvement and application of a one-dimensional model (within Delf3D-FM development) with a focus on morphology under synchronized operation with RTC for a cascade system of dams
• Implementation of optimization algorithm in RTC considering sediment management and habitat suitability (not considered yet in RTC).
• The HABITAT model has always been used for species and groups of species, translating environmental factors into habitat suitability curves and identifying the most limiting factor in terms of ‘too shallow water depths, too fine sediments, too turbid’. A first step to link HABITAT modelling more to the environmental approach, is to connect the species habitat to specific components of the flow requirement: “higher peak discharges are needed to prevent silting up of the gravel thereby creating suitable spawning habitat”, or “discharge is too low, and hence the con

Valorisatie

New version of Habitat and Knowledge to develop further Habitat model. 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.
Development of Delft3D-FM (2D and 1D) 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.

Link naar projectresultaten…