Temporary solutions13 February 2012
Temporary dams can offer a cost effective solution for a number of situations, including flood management and emergency repair work. Below we take a look at some of the options available on the market
AquaDam from Albion Water Structures Ltd is a re-useable temporary dam system designed for user installation. The system includes water filled temporary dams that are inflated using a pair water pumps. The dams have been designed to operate in both stationary and moving water. Each size of AquaDam has a limiting maximum controlled water depth, and, provided the dams are operated within this parameter, are designed to form a safe and reliable temporary dam.
AquaDam is currently available in a range of sizes to control water up to a maximum of 1.8m, and are available in lengths to 300m with joining collars. The table right shows the different sizes offered.
The standard range which is suitable for water depths up to 1.8m and are sold to the length required. Budget dams, designed as a substitute for improvised dams, come in a range of standard lengths from 5m to 30m and are suitable for water depths up to 70cm. The Flood Pro range are smaller dams designed to be deployed in 30m/100ft sections by two man deployment teams.
AquaDam has been used to de-water a mill leat to allow for the installation of a micro-hydro generation plant at Hainbury Mill in Somerset, UK.
The project involved a short mill leat with a very irregular leat bed of soft silt and steep sided banks. Specific issues at the site included a very low head of 1.6m, access issues as the location was in landscaped gardens, and flooding problems.
The AquaDam used at the site was 10m (CAN YOU CHECK AS SAYS 18M online) in length with an MCD of 1.8M and cost UK£3,900.
The installation was performed by the dam purchaser, assisted by the hydro project installer Western Renewable Energy.
With a pair of two inch pumps and a team of six novice installers, the AquaDam took around two hours to install.
A current project where an AquaDam is proving its worth is the £6M project to transform Burgess Park in the Elephant and Castle area of South London,
The lead contractor on this project is Balfour Beatty, sub contracting to Miles Water Scapes Ltd.
An aquadam is being used to aid construction and to protect the fish at the project. This AquaDam was ordered as a 150m waterline length temporary dam in sections of 2 x 50m, 1 x 30m & 1 x 20m with joining collars, at a cost of UK£24,000. The system has been used three times so far, with a further fourth use planned.
In the first use, a 150m temporary dam was positioned in a dog leg shape. The dam was partially deflated to neutral buoyancy and then repositioned for phase two, where it was also used in a further dog leg shape. For the third use, it was used as a 75m dam in a gentle curve shape. It’s intended fourth use will involve three “U” shaped deployments to facilitate the installation of a series of jetties.
Its total use has been 350m-500m of cofferdam with controlling depth capability of 85cm for less than £25k.
The AquaDam has been used at the Burgess Park project as the lake is an artificial lake formed with a plastic liner. Avoidance of damage to this liner was a high priority. An option to empty the lake and relocate the area’s fish stock followed by lake refill was considered, but the cost of the refill water was in excess of AquaDam purchase price.
For further information on the AquaDam system, please visit www.albionwater.eu or email Greg Shakshaft on [email protected]
Working on site
The PortaDam System from OnSite is designed to be a versatile temporary dam system. The temporary dam/flood protection system utilises a steel supporting 'A' frame structure upon which a tailored vinyl liner membrane is suspended. The resultant hydrostatic seal provides a watertight barrier behind which, essential maintenance or construction works can safely be carried out. The support structure has been designed to transfer hydraulic loading to a near vertical load, thereby creating a freestanding structure with no additional bracing or supports to impinge upon the work area.
The standard Portadam system can dam depths of up to 2.5m. According to OnSite, should water levels rise beyond the designed crest level of the dam, the water is able to overtop without affecting the overall structural integrity of the dam.
The system is designed to be quickly installed over most irregular contours, and in a number of different configurations and to different length. It can be installed in pre-existing deep water applications, such as canals and rivers, as well as sites where flooding has already occurred.
Typically, there is no requirement for any riverbed preparation prior to installation of a Portadam®, or the introduction of any fill material, meaning the Portadam® system is one of the most environmentally friendly methods of temporary dam construction available today, with no introduction of harmful materials to the watercourse. Also, compared to driven sheet piling, noise pollution is almost non-existent.
For further information on the system, visit www.onsite.co.uk.