Aquatic Engineering

AGA has been leaders in the aquatic engineering industry since 1977, for over 40 years our teams have developed and built aquatic environments that are environmentally conscious and maintain a natural balanced environment.

Aquatic Planning & Development

A.G.A. Group has direct experience in dealing with all statutory bodies including the Environment Agency, Local Planning Authorities, and Natural England, in applying and obtaining planning consents for fish farms, recreational fisheries, private ponds and lakes.

Ecology and Land Management Consultants

  • Handle legislative issues with an understanding and awareness of how legislation impacts the client’s project
  • Format data to establish conditions relevant to the subject under review
  • Interpret data and report its value and significance
  • Identify and consider any potential contaminant sources that could have an adverse impact
  • Complete detailed report writing, for interpretation by non-technical parties
  • Communicate in the round with clients, regulators and sub-contractors

We can offer design and project presentation to the customer for aquatic and associated infrastructure work. Carried out “in house” by our own team, we are never happier than to have the opportunity to work with a client to design their aquatic project.

Aquatic Construction Planning & Construction

For over 30 years AGA Group has undertaken construction projects within the sphere of aquatic environs. We understand that all project needs are different that is why our integrated approach ensures that all aspects of the construction process will be taken into account including the appropriate materials, ecology of the area and environmental considerations.

From Concept to Completion

We have developed specialised techniques for construction and restoration projects that combine traditional and modern materials. In this way, we are able to provide ‘green’ solutions even when hard engineering components are unavoidable. We strike a balance to ensure that the project objectives are achieved in a way that gives full consideration to biodiversity and sustainability. All of the regulatory bodies and their statutory consulates now expect this to happen as a matter of course.

Wetland Engineering Conservation Management

AGA Group specialises in providing environmentally sensitive solutions to constructed wetlands. These may be engineered for many reasons, for example, reclaiming habitat lost to development, managing stormwater runoff or to emulate the features of natural wetlands.

Wetland construction, conservation and regeneration

AGA Group specialises in providing environmentally sensitive solutions to constructed wetlands. These may be engineered for many reasons, for example, reclaiming habitat lost to development, managing stormwater runoff or emulating the features of natural wetlands.

Habitat enhancement and conservation

Measures may be called for to replace any disturbed ecological balance i.e. excessive living or dead vegetation, pollution or encroachment. We treat these project sites with extreme care and have the facilities and materials that return the site rapidly to its natural state.

Coir pallets, for example, offer an excellent natural solution to establish marginal and emergent aquatic vegetation. The success of A.G.A. coir pallets lies in their diversity; they can offer rapid vegetation, provide habitat and protect against erosion

Image showing eric muhr BRrnjuENDlA unsplash scaled

Fluvial Engineering
(River Engineering)

AGA Group undertakes a whole range of river management and restoration projects. We formulate clear sets of aims and project outlines before embarking on restoration and enhancement developments; our plans will incorporate future goals and constraints to ensure the project’s blueprint is one of stability and sustainability.

When working with dynamic fluvial systems we emphasise that this planning stage is crucial both from an environmental and health and safety standpoint in order to ensure the smooth running of the project.

It is from our understanding of fluvial processes that informed management strategies are formulated. With this type of undertaking, we will often work in consultation with the Environment Agency, Local Authorities and other statutory bodies.

Restoring meanders to straightened rivers

In England, during the 1960s many rivers were artificially straightened to reduce flooding. It is now acknowledged that far from reducing flooding events, straight channels may increase the chances due to volumes of water pushed rapidly through the waterway.

A.G.A. Group carries out projects for the reinstatement of natural river meanders, which effectively mitigate the problem of flooding by restoring a more natural flow regime to the watercourse.

Enhancing straightened river channels

Where the opportunity to reinstate meanders to artificially straightened rivers is unrealisable, we offer a number of other management techniques which can be used to enhance the channel and provide good habitat for fish and plant species.

Marginal planting is a common enhancement technique, which acts to improve habitat and provide spawning areas for fish communities, by using desirable aquatic species such as:

  • Lesser Reedmace (Typha angustifolia)
  • Flowering Rush (Butomus umbellatus)
  • Reed Sweet-grass (Glyceria maxima)
  • Reed Canary-grass (Phalaris arundinacea)
  • Sweet Flag (Acorus calamus)
  • Arrowhead (Sagittaria sagittifolia
  • Water Plantain (Alisma plantago-aquatica).

Another useful technique is to recreate pool/riffle sequences, effectively altering the flow regime and creating sections of fast flowing shallow water, ideal conditions for migratory and non-migratory species to spawn.

Riffles will also help to oxygenate the water, as with any areas where the air-water interface is increased, so dissolved oxygen levels increase, improving water quality and enhancing fish health.

Revetting and Supporting River Banks

Bank-side erosion is a common riverine problem and one which A.G.A. Group is particularly successful in remediating practices.

There are a number of revetment techniques which we employ to control or repair bank erosion. The choice of erosion prevention measure employed is heavily dependent on site conditions and, as such, there is no ‘one cures all’.

A.G.A. Group will, wherever appropriate, focus on aquatic engineering which incorporates bio-engineering techniques that reduce erosion by using such materials as coir, willow, vegetation and other natural materials to support and revet banks. These traditional techniques will often provide erosion control without the need for further hard revetment methodologies.

Pre-vegetated coir rolls offer excellent protection by effectively building a new bank which can be back-filled to provide a natural effect. By using pre-planted coir fibre rolls placed on faggots or rock rolls we can create ‘new’ bank-sides so erosion can be effectively stopped.

Coir is a very effective natural material which can be laid in mats which help to reinforce the bank, or used as edging to act as a barrier to erosion. After the turf reinforcement mats (TRMs) are laid down and pegged in position, plant species soon colonise, or can be seeded after installation, with the coir acting as the perfect germination medium. Depending on the time of year banks can look naturalised again in as little as 6-8 weeks.

Rock rolls can be incorporated into many river restoration projects and provide long term stabilisation.

We do not exclude hard engineering solutions, these are effective and have their place. We will however, where possible, incorporate our bio-engineering systems to soften the appearance and vegetate these structures thus making them environmentally enhancing.

Utilising silt from the river bed to back-fill behind the new structure not only helps as a robust erosion prevention technique, but also allows the removal of a quantity of silt from the river bed without the need for consents.

Reed Bed Construction

A.G.A. Group supplies, installs and commissions multi-functional reedbed systems.
Consult us in the initial planning stages, and we will offer the most prudent cost effective solution for your requirements.

Horizontal flow reedbeds

Free Water Surface and Sub-Surface Horizontal Flow reedbeds work particularly well for low strength effluents, or effluents that have undergone some form of pre-treatment.

Whilst not effective in reducing ammonia they will almost always reduce BOD (Biochemical Oxygen Demand) and SS (Suspended Solids) levels. These systems play an invaluable role in the tertiary treatment and the polishing of effluents, and as a safeguard against shock loadings.

A typical application would be to treat the discharge from a package sewage treatment plant that is unable to meet the discharge consent standard required on its own. Talk to our consultancy team for advice.

Vertical flow and combination reedbeds

Vertical flow reedbed systems are much more effective than horizontal flow reedbeds and are capable of handling much stronger effluents with a longer lifetime value. Not only will they reduce BOD and SS levels but also ammonia levels while eliminating odours.

Reedbed waste water treatment plants

We can construct wetland systems for primary and secondary treatment of sewage and stronger waste waters. They have a particular role in the nitrification of effluents – the removal of ammonia.

We offer a range of sizes of floating modular reedbeds (Eco-Islands); these may be utilised individually or joined together to build up a much larger structure suitable for industrial effluent control. They provide an ecologically sound A.G.A. technique to effluent control which is both aesthetically pleasing and effective. They can be gravel filled at the base to maximise their filtration potential.

Floating reedbeds

Our floating reedbeds are constructed from a durable, buoyant, long-lasting platform supporting a coir pallet planted with Common Reed (Phragmites australis), or a variety of similar aquatic species to the client’s preference. The coir provides an ideal growing medium for the reeds, allowing them to thrive in previously uncolonised areas

Floating reedbeds (Eco-Islands) both enhance water quality by filtering out suspended solids and by playing host to bacteria which break down harmful pollutants, up to industrial scale. Reedbeds are now considered an important management tool in wetlands and provide a number of services besides effluent control such as reducing algal blooms and providing cover for spawning fish.

As the UK’s largest producer of Phragmites australis (Common Reed) A.G.A. Group are able to offer supplies for year-round installation

Ecological reedbed systems & constructed wetlands

Our pre-vegetated plant pallets are, more often than not, the initial reed supporting system, used for the creation of habitat, the stabilisation of wetlands and waterside banks.

The real value of AGA systems comes to the fore with the use of natural materials and established growing vegetation to bring together biological, ecological and engineering concepts to vegetate of enhance wetlands.

By far the most cost effective and practicable way of creating or restoring reedbeds in wetland areas is the installation of coir pallets.  This is a proven solution achieved using pre-grown coir pallets from our own wetland nursery, we ensure a reliable supply of well rooted, established aquatic plants growing in coir rolls or pallets designed to adequately meet the hydrological and biological needs of the site and withstand reasonable wave impact.

Flood Defence Constriction & Management

Sustainable Drainage Systems (SuDS)

We work with consultants and developers to design, construct and commission sustainable drainage systems that reduce the impact of new and existing developments with respect to surface water drainage discharges.

We can replicate or develop natural systems that are cost effective solutions with minimal environmental impact, releasing treated surface water run-off slowly back into suitable water courses.

Aqua Systems Barrier and Portable Cofferdam System

AquaBar water-filled cofferdams replace outdated sandbags and earth backfill.

Our AquaBars can be arranged to create flood control barriers and floodwater diversion channels. It can be a non-invasive way of protection by withholding flood water, they are held in place by the weight of water held within them. They save time over some conventional methods, are re-usable and are logistically more efficient, they pose a little disruption to the land from heavy transport.

The inherent flexibility and construction of the materials used to enable the AquaBar to conform to most surfaces, thus providing an excellent seal and keeping water seepage to a minimum.

Barrier Bank flood defence system

This is an innovative temporary or semi-permanent flood system designed for fast reaction to imminent, intense flooding. Barrier Bank is a unique pattern of robust PP fabric bags and waterproof Velcro connections that provides a protective envelope around land, buildings or other sites.

Barrier Bank High Wall

A temporary or semi- permanent flood system designed for fast reaction to imminent flooding
Barrier Bank Surface Wall (ideal for surface water flooding)
Designed for surface water flooding and flash flooding of up to 1.4 metres

Quick Wall Mini

A unique pattern of robust PP fabric bags with waterproof Velcro connections.

Wetland Engineering & Conservation Management

AGA Group has a wealth of experience in undertaking a variety of river management and restoration projects and is equipped to employ a wide range of recognised techniques.

We provide an extensive range of materials and systems for Erosion Protection on:

  • Riverbanks and wetlands.
  • Lake/reservoir banks and shores
    Dams, revetments and balancing ponds.
  • Unstable and over-steep slopes
  • Spillways and irrigation channels

We make use of the most appropriate natural or man-made materials, and often a combination of both. In this way we can provide immediate short or long term surface protection that can mean a rapid return to the location’s natural state.

HDPE Pond Liner design

Bioengineering and soft engineering erosion control measures

Geotextile fabrics & composites

Geosynthetics offer many benefits over traditional construction techniques, by reducing project costs, construction times and reducing the volume of natural materials that are used and therefore reducing the environmental impact of transportation.

Bank-side erosion is a common riverine problem, particularly in fast-flowing (artificially straightened) channels and there are a number of revetment techniques that can be employed. The choice of erosion prevention measure employed is heavily dependent on site conditions and as such, there is no ‘one cure for all’.

 

Hard engineering methodology for erosion control

coir roll and faggots Diagram

Desilting & Dredging Of Ponds Lakes & Rivers

AGA Group provides the resources and expertise for the desilting and dredging of lakes and ponds as well as larger reservoirs. We will undertake all aspects of the project required by the client.

Over a period of years, as they fill with mud, silt and plant materials, many ponds and lakes will require desilting. When this happens, oxygen levels are reduced and as a result, it can produce acidic conditions, reducing the fertility of the pond and putting fish stocks at risk. Desilting and dredging a pond means that it stays clean and functional.

These Services Include

  • Fish removal
  • Environmental Impact Assessment (EIA)
  • Consultancy and advice
  • Depth surveys and silt analysis (this can affect disposal considerations).

We work using environmentally sound practices that are cost-effective and safe for desilting and dredging lakes and ponds.

Systems & Strategies Used

  • Mechanical dredging
  • Hydraulic pump and floating pump dredging
  • Silt digestion
  • Silt pumping
  • Silt dredging
  • Silt removal or reuse

Pond & Lake Lining Services

A.G.A. Group design and construct water containment systems. Our integrated approach, developed over the last 30 years means, that all aspects of the construction process will be taken into account, including the ecology of the area and environmental considerations.

Typical lining systems used in construction

AGA Group undertake all aspects of turnkey construction from "Concept to Completion"

  • Agricultural Reservoirs
  • Balancing and Attenuation Ponds – SuDS
  • Fish Farms
  • Recreational Lakes and Ponds
  • Water Features

 

    Lake and Pond Construction

    Our resources enable us to supply the finest, cost effective materials that a project may require; geomembrane liners, geotextile protection/filter fabrics and bank stabilisation cells are just a few.

    As the UK’s largest producer of vegetated coir units (the method of using vegetation as a permanent structure within aquatic environs) , we can offer year round supplies for installation when ideal conditions prevail.

    By opting to use our professional and experienced construction and installation teams, you will have access to some of the most economical, innovative and reliable installation techniques available.

    For over 30 years our group has had the most successful record of working with, and for, clients throughout the UK.

    Talk to us, to see how we can join with you for partnership ventures and turnkey projects.

    These Services Include

    • Large ponds and lakes
    • Amenity and recreational lakes or ponds
    • Wildlife ponds
    • Environmental and educational ponds
    • Balancing ponds and pollution control
    • Reservoirs
    • Fish farms
    • Koi ponds
    • Ornamental ponds

    Boardwalks, Bridges and Platforms

    AGA Group has a wealth of experience in undertaking a variety of river management and restoration projects and is equipped to employ a wide range of recognised techniques.

    Boardwalks can be constructed in classic timber design or mounted as a floating boardwalk on modular pontoons

    So if you are interested in boardwalks, bridges and platforms, or any other type of structure, please feel free to contact us to discuss your requirements.  We are always please to advise, and go that extra mile to provide a great service.

    View of completed Diss Mere Boardwalk

    Types Of Construction

    • Angling Platforms and Fishing Pegs
    • Platforms and Decks
      • Constructed for safety, with a non-slip surface from which anglers can fish.
    • Dipping Platforms
      • We provide a secure and clean area for children to kneel and keep their balance.
    • Bridges
      • Designed to span anything from a ditch to the main river.
    The completed project

    River & Lake Habitat Enhancement

    A.G.A. Group specialise in the use of ‘soft’ bio-engineering techniques to carry out both still water and river habitat restoration and enhancement.

    This work is carried out using both natural and semi-natural solutions to improve the aquatic and surrounding ecology and biodiversity.

    The techniques employed range from very simple planting techniques, to the use of willow mattresses, willow faggoting and the use of coir rolls to establish aquatic plants in difficult situations.

    Plants can be used to buffer natural erosion such as that caused by wind and wave action and where the conditions are hostile towards natural colonisation. This is often best achieved by establishing the plants in coir rolls before positioning and fixing the planted coir roll into place. Coir rolls establish quickly and give added benefits in situations where wildfowl might make the establishment of plants difficult.

    Our many years of practical fishery management experience has allowed us to develop techniques in protecting plants both during and after establishment from grazing by ducks, geese and swans.

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    AGA Headquarters

    Merton Hall Ponds, Merton, Thetford IP25 6QH

    Call AGA