This paper presents the results of the experimental and numerical investigation of interactions between surface flood flow in urban areas and the flow in below ground drainage systems (sewer pipes and manholes). An experimental rig has been set up at the Water Engineering Laboratory at the University of Sheffield. It consists of a full scale gully structure with inlet grating, which connects the 8 m(2) surface area with the pipe underneath that can function as an outfall and is also further connected to a tank so that it can come under surcharging conditions and cause outflow from the gully. A three-dimensional CFD (Computational Fluid Dynamics) model has been set up to investigate the hydraulic performance of this type of gully inlet during the interactions between surface flood flow and surcharged pipe flow. Preliminary results show that the numerical model can replicate various complex 3D flow features observed in laboratory conditions. This agreement is overall better in the case of water entering the gully than for the outflow conditions. The influence of the surface transverse slope on flow characteristics has been demonstrated. It is shown that re-circulation zones can form downstream from the gully. The number and size of these zones is influenced by the transverse terrain slope.

No abstract

Concern has arisen as to whether the lack of appropriate consideration to surface water in urban spatial planning is reducing our capacity to manage surface water flood risk. Appropriate tools are required that allow spatial planners to explore opportunities and solutions for surface water flooding at large spatial scales. An urban surface water balance model has been developed that screens large urban areas to identify flooded areas and which allows solutions to be explored. The model hypothesis is that key hydrological characteristics; storage volume and location, flow paths and surface water Model results were used as a basis to develop solutions to surface water flooding. A least cost path methodology was developed to identify managed flood routes as a solution. These were translated into model inputs in the form a modified OEM. It was shown that the simple and fast representation of flood routes and surface storage is of considerable benefit for scenario analysis.il ACKNOWLEDGEMENTS

No abstract

Change in external factors, such as environmental legislation and climate change, will mean the future of sewerage systems is likely to be different from the past. Combined sewerage systems comprise the vast majority of existing sewers in countries such as the UK. A study funded by UK Water Industry Research Ltd has reviewed the current state of sewerage within the UK, the likely drivers for change and the consequent future impacts over a 75 year timescale. Potential responses to address the anticipated changes have also been considered. It is concluded that due to the wide extent and value of existing sewer systems, these will continue to be used for the foreseeable future. However, in order to meet the major challenges as a result of changing external factors, these need to be operated more effectively, new ideas need to be explored and moves to develop better and more integrated water management systems need to be started if sewer systems in the UK are to provide the anticipated required levels of service well into the 21st century.