Overview

SDS WaterBank® Intellistorm® rainwater management system and SDS SYMBiotIC™ were used in a South West Water pilot project to establish whether residential smart rainwater storage tanks could ease headroom issues in a combined sewer network. The overall purpose of the project was to improve the quality of bathing water in the bay at Combe Martin, Devon.

Background

Combe Martin is a small resort, located in a sheltered valley, at the western edge of Exmoor National Park on the north Devon coast. Two water courses enter the 110m-wide sandy bay, the Furze Park Stream and the River Umber which drains directly from the northern slopes of Exmoor. Rainwater from the steep slopes in the area, which is mostly agricultural, often floods the river, overwhelming the sewerage network.

Multiple improvements and repairs made to the serving CSOs over the past 25 years have so far failed to rectify the discharge of polluted water into the bay.

Due to insufficient water quality standards, as monitored by the Environment Agency under the Bathing Water Directive, bathing at Combe Martin has been classed as poor from 2017 to 2020; in 2020 alone, 62 pollution risk warnings were issued.

Work undertaken

Working with South West Water, SDS recruited residents from 34 houses in a carefully selected catchment. In addition to a number of water quality awareness training campaigns organised by the Environment Agency, a local community action group, ‘Combe Martin Water Watch’, has been established to continue this work.

Furthermore, the Environment Agency, Catchment Sensitive Farming and South West Water are working with farmers in an effort to reduce polluted run-off from the surrounding agricultural land.

SDS product features

With the assistance of South West Water’s engineering consultants, Stantec, each house was equipped with a domestic version of the SDS Intellistorm® system, comprising of a slim, space-saving 275-litre-capacity rainwater storage tank, connected to the main downpipe from the roof and fitted with a small, solar-powered control box.

Together, the tanks have a combined storage capacity of over 9,500 litres. Each is controlled by a solar-powered, weather-protected computer positioned at its side; data received, via SDS SYMBiotIC™, over the first 6 months of the project indicates that a single ‘smart’ water tank stores as much water as 7 traditional water butts and is on course to attenuate more than 3,500 litres per year.

Residents consequently save money on their water bills by recycling the collected rainwater for uses such as watering the garden and washing the car.

Comments

“There are many complex factors affecting the bathing water at Combe Martin and some of it is down to how well the sewerage network copes with sudden high volumes of surface water runoff. South West Water is taking a multi-faceted and partnership approach to tackling these problems, including working with SDS and village homeowners to pilot smart water tanks.”
– Dave Pateman, Wastewater Asset Manager, South West Water