South West Partnership for Environmental and Economic Prosperity (SWEEP)

The lack of tools possessed by planners, designers, and engineers for making straight forward evaluations on how and where to place sustainable drainage systems (SuDS), has increased the reluctance to implement SuDS into designs. The South West Partnership for Environmental and Economic Prosperity (SWEEP) 006 will address this.

Water is vital to the beginning and continuation of life around the world. Nevertheless, with wet countries like the UK becoming wetter, and rainfall intensity ever-increasing, the overabundance of water can threaten the stability of livestock, infrastructure, and essentially lives. Consequently, effective drainage systems have become an increasingly crucial aspect to the prevention of these disasters.

Traditional drainage solutions, although very effective, tend to be costly and unfavourable to the environment - due to the placing of storage tanks through the excavating of land. On the other hand, SuDS such as swales, filter strips, green roofs, and reservoirs tend to be above ground, and although each provide less storage space when compared to big underground chambers, SuDS can be vital to the attenuation of peak flows going into drainage systems.

The South West Partnership for Environmental and Economic Prosperity (SWEEP), is a research group funded by the National Environment Research Council (NERC). Consisting of 15 projects from SWEEP 001 to 015, NERC aims to gain economic, environmental, and conservational benefits for South West England.

SWEEP 006 is a research project conducted by Catchment Modeller Shruti Virgincar and Professor Zoran Kapelan - Professor of Water Systems Engineering at the University of Exeter. The project will develop a tool that not only helps drainage engineers but a wide variety of partners in finding the best place to locate sustainable drainage systems with the greatest possible benefits. 

Suds 2

The study builds upon Pell Frischmann’s Surface Water Analysis Tool (SWAT) to create a mechanism that strategically separates surface water from a combined drainage system. This identifies where the greatest upstream impermeable area is connected to drainage networks, where the majority of surface water is going, and its distance to a watercourse.

At the moment, to integrate a swale or pond into an area, organisations such as Westcountry River Trust would have to go out on site to investigate the suitable places and best fit for sustainable drainage. This research will save time by mapping the most effective systems and relevant places to integrate SuDS more widely.

This tool will not only act as an updated geographic information system (GIS) to visually analyse environmental and ground conditions, but will incorporate robust engineering that quantifies improvements in attenuation, biodiversity, and water quality - demonstrating a level of innovation that is otherwise unavailable to drainage engineers in the South West.

Current findings have identified considerations concerning upstream impermeable areas, green space availability, buildings, and topography – such as, the incompatibility of steep slopes and possible solutions to mitigate excessive run off. To achieve this, research and analyses are taken from previous models, approaches, and literature to build the best possible solutions.

Conferences with stakeholders; South West Water, Westcountry Rivers Trust, Torbay Council, and Exeter City Council, have allowed Pell Frischmann to present the SWAT, provide research updates, and partake in an open knowledge sharing discussion. This saw key points raised, such as the exclusion of infiltration in the current SWAT, as the previous system assumes all rainwater fallen onto a catchment runs into the drainage system, without taking into account substitute areas water may drift to. However, Further complications rise as greater variables are added into the tool - creating supplementary layers of uncertainty that need enhanced configurations.

The availability and quality of data acts as part of the solution for ensuring accuracy within the tool. Our partnerships with specialist stakeholders have provided access to key data in aid of ongoing research. An example of how stakeholders have helped was demonstrated at the conference, where Torbay Council suggested Torquay as a good catchment to use as a prototype for the model. By providing information on planning applications and data on present drainage systems, Torbay Council have enabled access to files that would not be available otherwise.

The creation of the new SuDS software will meet stakeholder aspirations by providing benefits that equip Westcountry Rivers Trust with a tool to engage the public - offering knowledge and advice concerning the use of SuDS. Additionally, the tool will provide South West Water with a system that delivers an overall outlook of the costs attached to SuDS, whilst supporting business cases through the quantification of results.

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