Hidrostal Limited

Hidrostal are experts in the design, installation and commissioning of Eel and Fish Friendly Pumps. Our founder patented the first ever Fish Friendly Pump over 50 years ago. Our current range includes both Fish Friendly Pumps and Fish Transfer Pumps that are suitable for a wide variety of sizes and species of eels and fish. Our pumps find application in aquaculture, water extraction and land drainage settings. Following the adoption of the EU Eel Regulations, Hidrostal are also leading the way in the development of Eel and Fish Friendly Land Drainage Pump Station designs, and the adaption of existing facilities to comply with these regulations.

Company details

4 & 5 The Galloway Centre, Hambridge Lane , Newbury , RG14 5TL United Kingdom

Locations Served

Business Type:
Manufacturer
Industry Type:
Agriculture - Aquaculture
Market Focus:
Nationally (across the country)
Year Founded:
1960

This company also provides solutions for environmental applications.
Please, visit their profile in environmental-expert.com for more info.

Hidrostal: The original Eel & Fish Friendly Pump
Hidrostal are experts in the design, installation and commissioning of Eel and Fish Friendly Pumps.

Our founder patented the first ever Fish Friendly Pump over 50 years ago. Our current range includes both Fish Friendly Pumps and Fish Transfer Pumps that are suitable for a wide variety of sizes and species of eels and fish. Our pumps find application in aquaculture, water extraction and land drainage settings.

Following the adoption of the EU Eel Regulations, Hidrostal are also leading the way in the development of Eel and Fish Friendly Land Drainage Pump Station designs, and the adaption of existing facilities to comply with these regulations.

EU Council Regulation 1100/2007, more commonly known as the ‘Eel Regulations’, was adopted in September 2007 as part of international measures to arrest a rapid decline in global populations of the common eel.

Following a sudden drop in numbers during the 1980s, eel populations across Europe have continued to fall at an alarming rate, to the point where the species is now classified as Critically Endangered by the International Union for the Conservation of Nature.  Several factors are thought to have contributed to this drop in eel numbers.  These include habitat degradation, pollution, the introduction of a parasite that disrupts the eels’ migration, and mortality as a result of water extraction and water management activities.

The EU Eel Regulations define the means by which EU member states will implement and monitor solutions to the problems that face their local eel populations.  This implementation is now underway, with the development and delivery of Eel Management Plans.

Each Eel Management Plan aims to reduce eel mortalities caused by human activity to a level where 40% of eels have a high probability of ‘escapement’ to the sea. The Eel Regulations suggest a number of methods to achieve this level of escapement, including restriction of commercial eel fishing, modification of man-made structures to improve eel passage, restocking measures and the deliberate transportation of eels from inland waters to areas where they can more easily access the sea.

Of particular interest in the context of this website is article 2, paragraph 10 of the Eel Regulations, which states:

“In the Eel Management Plan, each Member State shall implement appropriate measures as soon as possible to reduce eel mortality caused by factors…including hydroelectric turbines,pumps or predators.”

Furthermore, the Eel Regulations go on to specify that the reductions in eel mortality resulting from this section of its Eel Management Plan(s) must be reportedby each member state.

The full impact of the Eel Regulations on the UK water supply and water management infrastructure is still being assessed, and is the subject of detailed discussions between the Environment Agency and other affected parties.  However, the paragraph above makes it clear that eel and fish friendly pumping solutions will become a requirement at the majority of pumping stations and water extraction points where eel populations have been identified.  Because of our expertise in the field of fish friendly pumps, Hidrostal are pleased to have played a significant role in the discussions to date, offering advice and guidance on the implementation of eel and fish friendly pumping solutions to the affected organisations and businesses.

How do we ensure that our pump design is fish friendly, and capable of passing live fish with minimal damage or mortality?  There are several factors that must be considered, and the areas for attention are best identified by considering those features of conventional pump design that can be classified as ‘fish unfriendly’.

Many of the water management pumping applications that present a risk to fish (e.g. pump stations) make use of conventional, axial-flow pumps.  Even someone with no experience in the area will quickly deduce from looking at the impeller design of an axial-flow pump, that it is definitely not conducive to the safe passage of fish.  In fact, the axial-flow impeller almost guarantees fish death or serious injury.  As a result, Hidrostal have developed two alternatives to the traditional axial-flow impeller, the F-Type and V-Type impellers.

To prevent fish damage, all 90 degree bends within a fish friendly pumping system should be long radius bends, rather than the short radius bends that are the norm.  Similarly, tight turns and high velocities at the intake should be avoided – a fish friendly pump requires a gentle turn from the radial to the axial direction so that fish are aligned with the flow on entry to the impeller. The velocities in the pipe work should be limited to less than two meters per second when the pump is operating at maximum capacity, i.e. when pumping against the minimum static head.

If a pump features a siphon then the paddle on the siphon breaking valve is also a potential cause of fish damage.  The effect of subjecting fish to a partial vacuum as they pass through the siphon requires further investigation to determine the tolerances of various fish species.  If it is determined that the partial vacuum is an issue then a number of alternative solutions are available.

Care and attention needs to be given to the downstream discharge “pour” point of any eel or fish friendly system.   Ideally the discharge point should be at, or below the downstream water level, or no higher than 0.5 metres above the liquid level.

This page has focused on the elements of conventional pump design that are liable to cause fish mortalities.  For more information on the ‘fish unfriendly’ elements of traditional land drainage pump stations, please see our page on pump station design or download our paper on the subject.