Hydro-Ecologically based Operation of run-of-river Reservoirs for Effective Sediment management and energy production (HEORES)

Description:

Freshwater is indispensable and one of the most important resources for humans. With the growing human population and increasing water demand for urban, economic, and industrial development, as well as due to climate change, water scarcity has become a serious global threat worldwide. Climate change is reflected mainly in a gradual increase of temperatures, which result in longer dry periods, frequently followed by heavy rainfalls, causing increased intensity and occurrence of floods and erosion processes. The changed hydrological conditions require proper adjustments of water management practices. Construction of water reservoirs, used for hydropower generation, offers the possibility to adapt to changed hydrological conditions, especially in terms of multipurpose water use. However, hydropower plant (HPP) reservoirs disrupt the dynamics of sediment transport and may have a negative impact on the riverine environment and water organisms. At the lower Sava, Slovenia, 5 dams were built in a cascading system between 1993 and 2017. Sediment deposition in water reservoirs and the need for removal of potentially contaminated sediment from the reservoir areas is a Slovenian, as well as worldwide problem. Sediment management under changing hydrological conditions is a challenge of global proportions. Existing sediment management practices in water reservoirs worldwide are mostly unsustainable and lead to the loss of the multifunctional role of such facilities, such as loss of water availability for different uses and reduction of the riparian space, which worsen habitat conditions and self-cleaning capacity of the water body. The additional problem represents contaminated sediment. Advanced, holistic sediment management strategy, which includes all elements of the natural sedimentation cycle and environmental concerns related to potential sediment pollution from point and nonpoint sources, offers sustainable management solutions. In the proposed project, a novel, active river sediment management strategy in hydropower reservoirs of the HPPs on the lower Sava, under changing hydrological conditions, will be developed. The strategy will assure to the highest possible extent of the restoration of natural dynamics (continuity) of sediment transport, considering also the environmental status of sediments. To establish the proposed management strategy, a holistic, interdisciplinary approach, which includes a detailed analysis of hydraulic conditions in the reservoirs and associated sedimentation processes, as well as analysis and origin of pollutants trapped in the deposited sediment layers, will be applied. Sediment transport/deposition simulations using detailed bathymetry and sediment grain-size data, applying different simulation tools (2D and 3D), including also corresponding data on sediment pollution will be employed. On the basis of the gathered data on the presence of hazardous substances, and identification and quantification of the sources of pollution based on advanced mass spectrometry methods, it will be further possible to define potential measures related to the removal of sediments and the alternatives of their disposal or re-use. The developed sediment management plan for the chain of HPP on the lower Sava River will contribute to the restoration of sediment connectivity along the river course and the improvement of the river channel’s ecological/habitat role. Despite the global problem of sediment management in water reservoirs, to the best of our knowledge, such holistic, innovative approach, considering all aspects of sediment cycle, characterization and identification of sources of pollution as well as modelling of hydrological and hydraulic processes supported by environmental data, has not been yet documented and implemented. The developed active sediment management strategy could be applied also to other HPP reservoirs on rivers with torrential character in Slovenia and worldwide.

Main goals:

Objectives of the HEORES project proposal are the following:
·         Analysis of the temporal dynamics of HPP reservoir filling with deposited sediments by bathymetry measurements
·         Detailed analysis of hydraulic conditions (water velocity range and direction) and related sediment transport/deposition processes in the HPP reservoirs along the lower Sava during changing hydrological conditions, considering also transport of pollutants associated with sediment particles.
·         Simulations of sediment transport/deposition using detailed bathymetry and sediment grain size data, applying different hydrodynamic simulation tools (2D and 3D), including also corresponding data on sediment pollution.
·         Creation of an inventory of hazardous substances and other water quality parameters in water and sediment deposits in the HPP reservoirs.
·         Identification and quantification of the potential sources of pollution based on isotope techniques for key metals and for the nutrients and organic substances using mass spectrometry.
·         Development of a sustainable sediment management plan for the cascading system (chain) of HPP on the lower Sava River, which will contribute to the restoration of sediment continuity along the river course and improvement of the river channel ecological/habitat role.

These objectives are fully in line with the SRA 2021 call as it addresses several EU societal challenges including water and climate. These objectives are in line also with Sustainable Development Goals Agenda 2030 – SDG 3: Good health and well-being for people, SDG 3: Ensure healthy lives and promote well-being for all at all ages, SDG 6: Clean Water and Sanitation, SDG 7: Affordable and Clean Energy, SDG 13: Take urgent action to combat climate change and its impacts SDG 14: Conserve and sustainably use the oceans, seas and marine resources for sustainable development, European Green Deal goals for EU to become climate neutral by 2050, and with the International Sava River Basin Commission (ISRBC) strategy (ISRBC, 2008) for Establishment of sustainable water management of the Sava River (Water in sufficient quantity and of appropriate quality for the preservation, protection and improvement of aquatic eco-systems for all kinds of use/utilization) and Undertaking of measures to prevent or limit hazards such as floods and droughts.

Project packages:

To achieve the project goals, the project with duration of 36 months (M) will be organised in 8 work packages (WP), consisting of corresponding tasks (T)

WP1– Analysis of hydrological/hydraulic conditions and sediment transport/deposition processes
·         T1.1 Detailed bathymetry measurements of the reservoir bottom
·         T1.2 Measurements of the hydraulic conditions in the reservoirs
·         T1.3 Continuous point and cross section measurement of suspended sediment concentration, water physical and chemical parameters
·         T1.4 Granulometric (particle size and shape) analysis of sediment samples

WP2 – Inventory of hazardous substances
·         T2.1 Identification of contaminants
·         T2.2 Survey on hazardous substances
·         T2.3 Prioritization of contaminants

WP3 – Hazardous substances and their transport under changing hydrological conditions
·         T3.1 Analysis of contaminants in water, sediments and SPM
·         T3.2 Assessment of hazardous substances under changing water discharges

WP4 – Identification of the primary sources of pollution
·         T4.1 Sources of contamination with nutrients, toxic elements, and organic compounds
·         T4.2 Source appointment of nutrients, toxic elements, and hazardous substances in water and SPM

WP5 – Modelling
·         T5.1 Development of a conceptual sediment transport model
·         T5.2 Building of 1D/2D hydraulic model
·         T5.3 Building of 3D model

WP6 – Recommendations for sustainable sediment management in reservoirs of the lower Sava
·         T6.1 Providing recommendations

WP7 – Dissemination, communication, and outreach
·         T7.1 Creation of the project web page
·         T7.2 Communication of the results among beneficiary institutions, local authorities, and public
·         T7.3 Dissemination of the research results
·         T7.4 Transfer of knowledge

WP8 – Coordination
·         T8.1 Coordination activities
·         T8.2 Meetings with co-financer