In October 2022, EV-INBO and TIIAME tagged 29 snowtrouts in Shakhimardan to track their movements and habitat use at the demo site before the construction of the hydropower installation. Although the manufacturer estimated that the tags would last one year, which was enough for our study, about ten are still active!

This provides an excellent opportunity as it provides us extra data, particularly in spring, as that proved to be the period that snowtrouts migrated over 10 km downstream for reasons we are still analysing. Therefore, scientists from TIIAME are still going to Shakhimardan regularly to track the snowtrouts. In addition, another 30 radio transmitters have been ordered and will be surgically implanted in the snowtrouts the coming spring to continue the tracking experiment. The goal of this following tagging experiment is to study if the hydropower installation and activation has an impact on the snowtrouts returning to the River Koksu after their downstream adventures.

We are currently analysing the tracking data that has been collected so far and in general, we observed that the snowtrouts move downstream in spring and early summer, but migrate back upstream in late summer and autumn.

Author and picture credits: Pieterjan Verhelst, EV-INBO

Since the beginning of the Hydro4U project, the partners have been working together on the planning and installation of two small hydropower plants in Central Asia.

For the demonstration hydropower plant in At-Bashy, Kyrgyzstan, in addition to the turbine components supplied by project partner Global Hydro Energy, Austria, many hydraulic steelwork components (stop logs, penstocks and trash racks, as well as a trash rack cleaner) were also planned. This is where the company Erhard Muhr GmbH, Germany, comes into play. They are experienced in manufacturing of hydropower equipment. As part of Hydro4U their core activities are the economic and ecological optimisation of the Hydroshaft Power Plant equipment, the manufacturing, supply and installation of trash racks with integrated cleaning device, flow regulation gates, stop logs, as well as the validation.

They calculated and constructed these in detail for the demo-site in At-Bashy using up to date CAD and FEM tools. From autumn 2023 until the end of 2023, this first phase was completed and Muhr focused on the production of these parts ever since including production planning and purchasing. Since 2024, they have been directly involved in the production of the components.

Components, such as the stainless steel guides for the top water dam panel, the regulating gate and the underwater dam panel and their lifting beams, and the supports for the shaft rakes are embedded in the concrete during construction work are ready for delivery to the demo-site. Due to the climatic conditions, the guide for the penstock is equipped with piping for a heating system. This system will keep the gate operational even in the harsh winter conditions in Kyrgyzstan.

The stop logs are made of lightweight aluminum in order to keep the crane capacities required for assembly and disassembly as low as possible. It is possible that the dam panels will already enable or support the damming and drainage of the construction site for the installation of the remaining equipment.

Author: Fabian Böttger, Project Management, Muhr

Picture credits: Muhr

The Hydro4U demonstration hydropower plant in At-Bashy has reached the detailed design phase. The use of dedicated structural analysis software has facilitated the adoption of an integrated BIM solution for the detailed design of the At-Bashy hydropower plant in Kyrgyzstan.

ILF Consulting Engineers Austria, which has been responsible for the detailed design of the At-Bashy demonstration hydropower plant, prepared formwork and reinforcement drawings for the construction of the modular Hydroshaft Power Solution (HSPS). During this process, optimizations and structural adjustments were made to the design; all using Building Information Modelling (BIM) – exemplifying how dedicated structural analysis software enables an integrated BIM solution.

The workflow used can be described as follows: The basic design was prepared by the Technical University of Munich (TUM) and provided to ILF for further development and review. After an initial review of the basic design elements, which include subdivision of the hydropower plant with construction joints, a three-dimensional (3D) structural Finite Element Model (FEM) was created. Dead load, earth pressure and external influences such as wind and snow were defined and applied to this model. As these loads induce stresses in the structure, these loads were calculated using the FEM.

As a result of these load calculations, the required reinforcement according to the applied load was then visible in the model. An example of the required stirrup reinforcement is shown below. The required reinforcement is defined and set for each element in the model.

The FEM is part of the larger BIM model, allowing plausibility checks regarding the location, quantity and spacing of the reinforcement to be conducted easily, and thus helping to ensure the practicality of its installation on site.

BIM models can be visualized using different views. In addition to full 3D views, sections and viewing angles can be displayed. Dimensions and further information can be added to the views. As only one model is used, these individual views can be used for formwork and reinforcement drawings. The reinforcement material list generated by the software could also be added to the drawings.

The BIM approach makes it possible for everyone involved in a project to have a good overview of the project at all times by using a cloud-based setup. The model is stored on a platform so that multiple users and experts from different disciplines can follow the progress of the project and intervene, if necessary.

In this project, the 3D model was stored in a cloud to give all relevant project members insight into the progress of the design work. The 3D model was used as the basis for discussing all coordination issues, which were resolved before the 2D drawings were started. The reinforcement was also part of the 3D model and allowed a high level of accuracy to ensure practicality on site.

The ILF Group is an international engineering and consulting firm that supports its clients to successfully identify, prepare and execute technically challenging energy, industrial and infrastructure projects all over the world in the following main business areas: Energy & Climate Protection, Water & Environment, Transportation & Urban Spaces and Resources & Sustainable Industry.

Picture credits and authors: Ulrich Beikircher, Rupert Feldbacher, Gabriel Pojer, ILF Austria

As visible in the project title of Hydro4U, sustainability is a crucial part of the developments in small-scale hydropower in Central Asia, particularly ecological sustainability. Ecological impacts of HP are for instance hindered migration, altered flow regimes (reduced flow, fast flow changes) or changed river morphology (sediment retention, increased embeddedness). The investigations performed by the European partners BOKU (A), EVINBO (B), Hydrosolutions (CH) and SJE (D) in cooperation with local partner TIIAME (UZB) in the demonstration sites Shakimardan at Koksu river in UZB, and Atbashy close to Naryn City at Atbashy river in Kyrgyzstan) focus on the mitigation of ecological impacts.

Hydrology in Shakimardan and Atbashy
The Koksu River, part of the Shakimardan basin, is influenced by a natural dam created by rockslide deposits, leading to the formation of lakes Kurbankul and Yashikul. The Koksu’s discharge, measured from 1948 to 2020, shows a minimum monthly flow of 1.25 m³/s in spring and a maximum of 16 m³/s during summer. The river’s annual sediment load is low due to upstream dam filtration, and it remains unfrozen throughout winter. The Atbashy River, a tributary of the Naryn in Kyrgyzstan, spans an area of 1,496 km² with elevations ranging from 2,455 to 4,843 meters above sea level. From 1970 to 1995, the Atbashy’s mean discharge was 16.6 m³/s, characterized by a nivo-glacial and strongly seasonal regime, with higher flows in warm months (mean discharge of 24.8 m³/s) and lower flows, accompanied by significant ice cover, in winter.

Fish populations in Central Asia and target species
The Mountains of Central Asia biodiversity hotspot consist of two major mountain ranges: the Pamir; and the Tien Shan with a total area of about 860,000 km² covered, including the 2 demonstration sites Shakimardan and Atbashy. Much of the biodiversity and natural ecosystems are in remote mountain areas and have still to be better studied. Therefore, any human impact directed on the change of aquatic habitat in these ecosystems has to be thoroughly assessed before implementation.

During 2021-2023 the ecological conditions and diversity of the ichthyofauna of mountain and foothill sections of rivers that are promising for the development of environmentally sustainable small-scale hydropower have been studied. Special attention was paid to the conservation of the diversity of fish key species and other aquatic organisms. To assess this integral component of the sustainable functioning of river ecosystems a special focus has been laid on the related habitat conditions.

One of main steps to achieve sustainable SHP is the identification of target aquatic key-species to be protected, having high importance for the protection of wildlife biodiversity. Collected field data on fish diversity, taxonomy and ecology of more than 50 river catchments in Kyrgyzstan and Uzbekistan have allowed to identify for the first-time main key fish species in upstream sections of Central Asian Mountain rivers (see also illustrations below):

1. Snowtrout – Schizothorax eurystomus (Kessler 1872);
2. Sewertsow rare-scaly osman – Diptychus sewerzowi (Kessler 1872);
3. Triplophysa ferganaensis (Sheraliev & Peng 2021);
4. Stone loach – Triplophysa sp.;
5. Glyptosternon oschanini (Herzenstein 1889).

Figure: Central Asian fish species as target of HP impact mitigation within Hydro4U (© Jennifer Clausen, www.jacdraws.com)

First findings on fish ecology of snow trout
Snow trout (Schizothorax sp.) belong to the most important fish species in Central Asia. They are adapted to fast-flowing, high-sloped mountain rivers. These fish, which reach up to 60 cm in length and 4 kg in weight, have a diet comprising algae, detritus, macroinvertebrates, and smaller fish. Their life cycle includes reaching sexual maturity at 3-4 years and a notable spawning period from April to September.

A habitat preference study of Schizothorax eurystomus in the Shakhimardan basin performed by Hydro4U researchers using point electrofishing revealed that juvenile snow trout prefer shallow waters around 20-40 cm of depth, while sub-adults and adults favor deeper areas of >30 cm and >50 cm, respectively. All size classes showed a high plasticity for diverse flow velocities and inhabit various substrates, with juveniles showing a preference for mid-sized substrates. This research is significant as it expanded the known distribution range of S. eurystomus and provided baseline data for environmental flow assessments.

Telemetry studies
Fish use various habitats to complete their life cycle such as spawning habitat, wintering sites and foraging areas. These habitats can be located at different parts of a river system and used by fish at different, seasonal-specific moments in time. Knowledge on the movement and habitat use of snow trout species Schizothorax eurystomus in the rivers of the Shakhimardan enclave is currently lacking. Hence, the effect of the planned hydropower plant in the River Koksu on the habitat use of snow trouts is unknown.
We used radiotelemetry to tag and track (position) 29 snow trouts in October 2022 to reveal their habitat use over the course of one year so we could learn when they reside and Koksu and why.

As the dataset is almost complete, we learned that the snow trouts seasonally visit the Koksu River, in particular during autumn months, which reasons for are to be clarified. However, these data suggest that the construction of the hydropower plant needs to take into account the life cycle of snow trout. In the next months the tracking data will be analyzed deeper to learn when and under which environmental conditions snow trout visits specific habitats. This information is not only crucial for the Shakhimardan enclave but can help future planning of river regulating structures in fish-ecologically, similar places in Central Asia.

Migration facilities and EFlow
The information for target species Schizothorax eurystomus has been used in Shakimardan for simulations with the habitat model CASiMiR to find a seasonally adapted E-Flow providing fish habitats in adequate quality and availability when the HPP is diverting part of the natural flow. The existing weir will integrate a state-of-the-art fish way and a bypass installation that enable up- and downstream migration for snow trout. Another artificial migration barrier within the river will be made passable as well. In Atbashy the modernized irrigation weir, equipped with a shaft turbine, will also integrate upstream- and downstream migration facilities. The attraction flow leading fish into the bypass channels and preventing them from entering the turbine inlet is investigated using a newly developed module of CASiMiR to possibly optimize the inflow conditions. The findings from these studies together with the results from the monitoring of the HPPs that both go into operation during the project period will deliver information for the adaptive management as part of the EIA.

Authors: Matthias Schneider (SJE), Tobias Siegfried (HSOL), Daniel Hayes (BOKU), Pieterjan Verhelst (EVINBO), Bakhtiyor Karimov (TIIAME-NRU), Erkin Karimov (TIIAME-NRU), Otabek Omonov (TIIAME-NRU).

Further contributors: Iana Kopecki (SJE), Tobias Haegele (SJE), Beatrice Marti (HSOL), Bernhard Zeiringer (BOKU), Johan Coeck (EVINBO), Ine Pauwels (EVINBO)

Small-scale hydropower (SHP) is not extensively exploited in Central Asia despite considerable potential to satisfy unmet electricity demand. The Mountains of Central Asia hotspot consists of two of Asia’s major mountain ranges: the Pamir; and the Tien Shan with the total area covered of about 860,000 square kilometers. Much of the biodiversity and natural ecosystems are in the remote mountain areas and have still to be better studied. Therefore, any human impact directed towards the change of aquatic habitat on these ecosystems have to be thoroughly assessed before implementation.

In light of the above, a key aim of TIIAME NRU’s research was to study the ecological conditions and diversity of the ichthyofauna of mountain and foothill sections of rivers that are promising for the development of environmentally sustainable small hydropower. A special attention within the project is paid to the particular importance of the conservation of the ichthyofauna diversity and habitat conditions as well as other aquatic organisms as an integral component of the sustainable functioning of river ecosystems.

To achieve the Hydro4U project objectives, it is key to perform studies on fish biodiversity, allowing the identification of key species of conservational and economic value, key river habitats based on, e.g., morphological river types or specific river sections, and legal protection sites.

To this aim, the team of TIIAME NRU conducted a series of “Central Asian Big Highlands Expeditions” to assemble baseline data on fish biodiversity and population assemblages, distribution and movements in rivers of CA, including information on measured chemical parameters. These field surveys also enabled knowledge exchange with Central Asian scientists and stakeholders.

To carry out the planned research, a special series of expeditionary research was organized in the mountainous regions of Central Asia. Field studies have been conducted in cooperation with regional research institutions and ichthyologists from Fergana and Termez state Universities (Uzbekistan) and Biological institute of Kyrgyzstan Academy of Sciences. Famous German ichthyologist, Dr. Joerg Freyhof from the Natural Museum of Berlin has participated in spring field studies as well.

To perform the listed tasks, the TIIAME NRU Team has conducted large-scale preparatory work since the end of 2022 – beginning of 2023. More than 50 preliminary planning sites throughout the whole Central Asian highlands were defined.

Before starting our surveys, we faced problems with obtaining permission for electrofishing. After long discussions and organization of two workshops dedicated to explaining the pros and cons, sampling permits for Uzbekistan and Kyrgyzstan were handed out eventually. TIIAME NRU is still aiming to acquire permits for ichtyological studies in Kazakhstan and Tajikistan. Therefore, here we provide data on the two republics of Kyrgyzstan and Uzbekistan.

In general, all research tasks have been fulfilled, despite the difficulty of visiting some distant upstream sections of mountainous rivers due to absence or very bad quality of roads. As a result of conducted field surveys, today we have collected large field data on fish diversity, taxonomy and ecology, as well as hydrology of more than 50 river drainages in Kyrgyzstan and Uzbekistan. Also, for the first time, the main key fish species in upstream sections of Central Asian Mountain rivers have been revealed. The identification of key species to be protected during implementation of different hydrotechnical constructions, including SHP, has high importance for the protection of wildlife.

The TIIAME NRU Team has also continued telemetry studies in Shakhimardan river basin to establish fish migration patterns in connection with the construction of fish passages on water intake and water fall in Koksu river. Results of conducted research have been presented in meetings and conferences and also published in regional journals.

Author: TIIAME National Research University

Picture credits: Erkin Karimov