Stormwater Management
DocumentsDate added
Authors
D.A. Phipps, R.M. Alkhaddar and M.G. Faram
Abstract
In recent years, various proprietary treatment technologies have evolved to reduce the polluting impact of urban run-off on receiving watercourses. The majority are ‘flow-through’ devices, designed to intercept and store pollutants in submerged chambers for later removal and safe disposal. Frequently, the performance of such systems is described solely in terms of ‘ability to remove pollutants from the inflow’, usually at specified discrete flowrates. However, it is suggested that this is insufficient to give a true assessment of performance and a critical parameter that is often overlooked is chamber ‘retention efficiency’, the ability of a chamber to retain stored pollutants once collected. In the current study, this parameter is investigated experimentally for a range of chamber configurations. Cylindrical chambers with different inlet orientations, internal components and hence flow dynamics are considered. The study identifies retention efficiency as being a major differentiator between designs, and concludes that chambers in which captured pollutants are stored in regions that are hydraulically isolated from the main treatment area are likely to be the most effective in practice.
Authors
David A. Phipps, PhD, Rafid M. Alkhaddar, PhD, James Dodd, Michael G. Faram, PhD, Pamela J. Deahl, P.E.
Abstract
With the objective of reducing the polluting impact of urban run-off on receiving watercourses, various proprietary treatment technologies have evolved, including ‘flow-through’ devices that are designed to intercept and store pollutants such as sediments and floatables for later removal and safe disposal. Frequently, the performance of chambers is stated in terms of ‘ability to remove pollutants from the inflow’, often at discrete flowrates. However, a parameter that is often overlooked is chamber ‘retention efficiency’, the ability of chambers to retain stored pollutants once collected. The paper presents the findings of both simulation and experimental studies of different designs of treatment chamber, focussing in particular on the ‘retention efficiency’ parameter. It is concluded that chambers in which the pollutants storage region is isolated from the main treatment area are likely to be most effective.
Author
Mr Alex Stephenson
Abstract
A novel integrated system providing hard engineered solutions to SuDS, Source Control and Rainwater re-use is described. The system is made up of four key facets; a flow control / attenuation element (Hydro-Brake
Authors
Authors
G P BOAKES, A STEPHENSON, J B LOWES, A C MORISON, A T USBORNE
Abstract
The Northamptonshire villages around Weedon in the upper River Nene valley, suffered disastrous flooding in 1947, 1992 and 1998, with Weedon Bec being particularly badly affected. The channel through the village is constricted by historic developments and the opportunity to enlarge the channels was not available. Restricted culverts under the railway embankments downstream compounded the flood situation.
To alleviate the problem the Environment Agency and Halcrow Group developed an upstream on-line storage reservoir scheme. The project includes a 450m long, 6.8m high clay embankment across the valley, with a culvert on the line of the original river channel to carry the controlled outflow. A 150m long concrete-block spillway carries excess flood flows over the embankment. The embankment site has been landscaped to minimise visual impacts and the borrow area has been developed into a large wetland area as a habitat for aquatic flora and fauna.
The key component of the flow control system is a 6.5 tonne, stainless steel Hydro-Brake
