At the Falgu river in the Indian state of Bihar the Austrian Hydro-Construct GmbH finished another notable rubber dam successfully. This was just in time before the beginning of the Hindu festival „Pitri Paksha“ in the second half of September 2022. The Austrian Company designed, delivered and installed the 390m wide air inflated rubber dam. Which is located right beneath the footbridge connecting the Hindu temples of Sita Kund and Vishnupad Mandir in the city of Gaya. As is usual for Hydro-Construct, this 3.10m high six span rubber dam breaks the record for being the largest rubber dam in India. Due to the intensive rainy season in this part of India the installation followed a tight schedule.

Since the beginning of the new millennium Hydro-Construct, based in Steyr, Austria, supplies rubber dams to India. Starting with rubber dams of usual sizes the recent projects shift the size limit for rubber dams to new dimensions. In line with this the Gaya Ji dam sets a new record for being the largest rubber dam in India. Six spans of 65m length and 3.10m height each addup to a total width of 390m. One of the advantages of rubber dams is that they provide the most cost efficient solution for such long flexible weir structures. Since ­rubber dams have no significant mechanical parts, only reduced maintenance efforts are necessary. In addition they will not pose an obstacle when they are fully deflated in times of flood. The Gaya Ji dam uses an air inflated rubber dam system to create a ­reservoire in front of the Hindu temples of Sita Kund and Vishnupad Mandir in the ­river Falgu.

Successful project
The Gaya Ji dam project is a project of the governement of the State of Bihar and the City of Gaya. As a general contractor NCC Limited, Hyderabad, India, has been appointed, which also was responsible for all civil works. Hydro-Construct won the bid for the supply of the rubber dam by offering the technically and economically best rubber dam solution. The rubber membran was produced by the joint partner Rubena, s.r.o., Czech ­Republic.

Challenging conditions
For Hydro-Construct it was the first cooperation with NCC Limited. Both companies were eager to make this project a success, also as it was possible to build the whole project during only one dry season and inaugurate it one year ahead of time. NCC project manager Girish Kumar Gopisetti praised the proven onsite team of Hydro-­Construct under the supervision of the joint partner AQUATIS a.s., Czech Republic, for its competence and determination, which were the key factors for the projects success. Even though the conditions with temperatures up to 40 °C and sometimes difficult communication were rather challenging all obstacles and difficulties could be eliminated.

Big celebration and ceremony
The rubber dam is part of a greater project including also a footbridge connecting the Hindu temples of Vishnupad Mandir and Sita Kund, two important pilgrimage sites. Traditionally in the second half of September during „Pitri Paksha“ tens of thousands of pilgrims make their way to Gaya to visit these temples and perform the „Shraddha“ ritual. Therefore special efforts have been taken to finish the project before the start of „Pitri Paksha“ festival. On Sep. 8th 2022 the Gaya Ji dam was inaugurated by Nitish Kumar, the chief minister of Bihar, in an impressive ­ceremony. Major governemental officials and thousands of people celebrated the finish­ing of the works and the unveiling of the inauguration stone. Not only during „Pitri Paksha“ the rubber dam and especially the colorfully illuminated footbridge is an attraction to ­visitors and locals alike.

Innovative developments
Besides its dimensions this rubber dam also features some new developments in rubber dam technology and regulation. For the first time Hydro-Construct installed a six span air­in­flated rubber dam, where in automatic ­operation each span could be operated in ­parallel or serial. An innovative way of connections between the control systems of all spans allows to operate the rubber dam also in groups of con­nected spans considering several ­oportunities of redundancy. This increases the resilience and operation safety of the system. Hydro-­Con­struct, in cooperation with the partner ESA GesmbH, Steyr, Austria, also implemented a V-notch bypass control algorithm. This helps to avoid the, especially for air inflated dam regultion, obligatory disturbant of the weir crest contour, which leads to a reduced stability and concentration of flow in limited areas of the whole width. Hydro-Construct also developed a new and patented double clamping rail system, which adds a supporting clam­ping rail to the upstream clamping rail. This successful project is leading to establish Hydo-­Construct India Ltd. which is responsible for the Indian market. The new company is managed by Ram Reddy as Managing Director­ and Bharath G. Reddy as General Manager.

Hydro-Construct Austria’s business prospektive
Hydro-Constructs prospects in India is posi­tively influenced also due to the activities of Hydro-­Construct India. In the meanwhile for five future projects Hydro-Construct is now in touch with the possible clients. Because of the successful completion of five projects in India Hydro-Construct is quite confident to be ­successful. These prospective projects are spread all across India. Hydro-Construct India also acts as a constulting and project planing company on the topic of hydropower. India as a growing economy has a huge demand for energy. Renewable energy sources such as ­hydropower have much potential when ­working towards the goal of supplying ­sufficient sustainable energy.

Notable water filled dam project
While the Gaya Ji dam is the most recent project Hydro-­Con­­­­­­­­­­­­­­­­­­­­­­­­­­­­struct finished in India, the rubber dam on Gomti river in Lucknow is also a notable rubber dam. With 275m width and 3,2m height it is also among the largest rubber dams. In con­trast to the Gaya Ji dam the rubber dam in Lucknow is filled with water. In terms of ­stability and regulation accuracy water filled rubber dams are advantagous compared to air inflated rubber dams. The rubber dam on Gomti river gets the filling water from a water tank to ensure that the water is of proper ­quality (high silt and pollution load in rivers) for filling the rubber dam. Hydro-Con­struct prides itself for being innovative and providing special solutions and so in Lucknow they ­implemented navigation locks, on both sides of the river, to allow boating traffic be­tween head and tail water. As lock gates also two rubber dams are used to create the manipulation lock chamber. The navigation locks are operated from an external control room. Although this rubber dam on Gomti river has been ­completed, its inauguration is still pending.