Rubber Dams: Frequently Asked Questions

A rubber dam typically consist of a durable rubber membrane that is clamped to a concrete foundation at the river bed or on top of a weir or dam structure. It is used to control the flow of water in rivers, canals, and other water bodies.

Rubber dams can be inflated and deflated to adjust the water level. When the rubber dam is inflated with air or water, it creates a barrier that can be used to control the water level and flow.

Rubber dam membrane is designed as a tightly closed system, and can be filled with either water or air through filling and deflation pipes. When the dam is filled, the volume of the membrane increases, causing it to rise and creating a barrier that raises the headwater in the river, thereby filling the reservoir.

The filling pressure can be regulated to control the height of the weir, enabling automatic regulation of the headwater level.

Rubber dams offer numerous benefits, including their flexibility and versatility, their ability to be customized to fit unique site conditions and project goals, and their relatively low cost and ease of installation. 

Rubber dams are more cost-effective than traditional dams, require less maintenance, and can be easily installed and removed. They are more environmentally friendly than traditional concrete dams, and can offer improved control of water flow and level. They are also eco-friendly and do not harm the natural habitats of aquatic animals.

Rubber dams have a wide range of applications including:

•    Water level control for irrigation and hydroelectric power generation
•    Flood protection
•    Environmental protection, such as creating wetlands or preventing saltwater intrusion
•    Navigation control in waterways
•    Recreation, such as creating water recreation areas 

Rubber dams can be used for extending storage capacity of existing dams, precise water level control for navigation purposes,  agricultural irrigation, separating sea water from fresh water in coastal regions, and regulating water and waste water in sewage systems.

Rubber dams can also be customized for other applications such as water sports, ecological water scene structuring, provision of cooling water, and urban planning.

Rubber dams are suitable for a wide range of water bodies, including rivers, canals, and lakes. However, the suitability of rubber dams depends on factors such as water depth, flow rate, and the surrounding terrain.

Rubber dams can be beneficial for a range of industries, including hydropower, water storage for irrigation and mining, water treatment, flood control, and recreational activities such as rafting or kayaking.

There is no limit to the width of a weir span, but we recommend splitting weirs longer than 60m into two weir fields for practical reasons. The cost is not significantly affected by the number of spans. Costs may increase if the customer wants to use the full potential of a split weir, as this will require additional equipment and shafts for independent operation. 

The expected lifespan of a rubber dam can vary depending on a number of factors such as the quality of the materials used, the operating conditions, the frequency of use, and the level of maintenance and repair practices. Generally, a well-maintained rubber dam can last for up to 25 years or more.

Rubber dams are suitable for winter operation, even in double-digit below zero temperatures. However, for air-filled weirs, valves must be located in a frost-free area to avoid condensation within the rubber membrane. Precautions like pumping through should also be taken when there is no water flow to prevent ice formation inside the membrane.

Rubber dams are not puncture or bulletproof, though we can design them to be bullet-resistant. The flexible nature of rubber dams allows them to convey debris and flotsam. Rubber dams can be punctured with massive force, but they will not burst due to rapid tearing. While the stiffness of the rubber material tends to close small holes, repair work should be carried out promptly. 

We offer both water-filled and air-filled rubber dams, each with its advantages and disadvantages.

From our experience, we suggest using water-filled rubber dams for almost any purpose, as they have a strictly horizontal weir crest in every filling state, tolerate high tailwater better, and are more tolerant against damages.

Air-filled rubber dams have shorter filling and deflation times and a smaller control shaft, making them ideal for situations where fast inflation or deflation times are required, and there is less space for a control shaft system.

Rubber dams require regular inspection and maintenance to ensure that they are functioning properly. This may include checking for leaks or damage, cleaning the surface of the dam, and ensuring that the anchoring and inflation systems are functioning correctly. If repairs are needed, they may involve patching leaks, replacing damaged components, or other measures as needed.

Automatic operation of rubber dams is now state of the art. However, we design our rubber dams to allow manual operation even if the automatic control system is not available. The relevant operation mode can be seen on the screen and switches on the control cabinet in the operator room. This feature is especially useful during maintenance activities or in case of emergency situations.

Yes, both sensors and motors are involved in the automatic operation of rubber dams. The most prominent motors used for filling and deflation under standard conditions are pumps in water-filled rubber dams and blowers in air-inflated rubber dams.

Depending on the size of the weir, we also install flap valves controlled by an electrical motor. Automatic operation depends on several sensors, such as head water level sensors, filling pressure sensors, and water level sensors in the filling and regulation shaft. Optionally, we also measure the tail water. The pressure sensing system limits the filling pressure of the rubber dam.

Yes, rubber dams require a permanent electrical power supply to run the motors. As for the need for a generator backup, deflation of the rubber dam will always be possible, and we offer battery backup as standard for the control system, including the motorized flap valves in air-filled systems. However, for operation of pumps or blowers, a 400 V power supply of up to 20 kW (for blowers) and about 3 kW for one pump is required. 

A control room is necessary to house the control cabinet and equipment for the rubber dam system. In air-inflated systems, the control room also includes the blowers. For water-filled systems, we need a control shaft system and a safe place for the control cabinet, which can be a small building located near the shafts.

The cost of a rubber dam can vary widely depending on the materials used and installation requirements. The cost of a rubber dam also depends on various factors such as size, shape, height, and location. It is best to contact a professional supplier like Hydro Construct for a quote based on your specific needs. Hydro Construct can provide a customized quote based on the design requirements of the project.

The installation time for a rubber dam can vary depending on the size, complexity of the project and the availability of resources. However, installation typically takes several weeks to a few months. Hydro Construct can provide an estimated lead time based on the project requirements.

If you are considering a rubber dam for your project, it is best to consult with a professional supplier like Hydro Construct to discuss your specific needs and requirements. We can provide guidance on whether a rubber dam is suitable for your project and recommend the best system based on your needs.