APEM partnered with ESI Ltd to deliver the UK’s largest abstraction study under AMP5, on behalf of Severn Trent Water.
Background to the project
Hydro-ecology plays a critical role in solving the world’s water problems as society’s demand for water increases and ecological considerations move to the front and centre of water resource management.
Severn Trent Water was required to investigate the ecological impacts of water abstraction at over 30 across the English midlands, and if necessary to implement mitigation measures. This represented the largest abstraction study in the UK under the National Environment Programme of the water industry’s five-year asset management plan running from 2010 to 2015 (AMP5).
What we did
APEM combined its ecological expertise with that of groundwater specialists, ESI Ltd, to develop a truly integrated and cutting-edge hydro-ecological approach to managing abstraction for Severn Trent Water.
By combining field data collected by APEM across multiple streams fed by sandstone aquifers in the English midlands, significant relationships were found between in-stream ecology and the hydrological effect of groundwater abstraction at medium-low flows (Q75). The study used the Lotic invertebrate index for flow evaluation.
Ecological impacts occurred when the effect of abstraction on Q75 flows exceeded 60 per cent and was greater than the effects of water quality, habitat and sampling season across sites (Bradley et al. 2014).
Regional hydro-ecological relationships have been combined with groundwater model outputs to generate predicted ecological impacts of groundwater abstraction across large areas of Severn Trent Water’s supply zone (Streetly et al. 2014).
- The work provided a sound basis for Severn Trent Water’s consultation with the Environment Agency; challenging the agency’s Environmental Flow Indicator at a local scale and allowing them to make regulatory decisions on a robust scientific evidence base.
- Severn Trent Water was able to rationalise its monitoring programmes, focusing resources on the most sensitive sites and those where the impacts are least certain.
- Planned reductions in abstraction for AMP6 were scaled back from several hundred Ml/d to around 12 Ml/d. These flow targets are now being applied at around 40 sites comprising Severn Trent Water’s National Environment Programme for AMP6.
- The model also proved a useful tool in the development of cost-effective measures to mitigate impacts where identified and achieve good ecological status.
- The work was published in two peer-reviewed articles:
- Bradley, D.C., Streetly, M.J., Farren, E., Cadman, D. & Banham, A. 2014. Establishing hydroecological relationships to manage the impacts of groundwater abstraction. Water and Environment Journal, 28, 114-123.
- Streetly, M.J., Bradley, D.C., Streetly, H.R., Young, C., Cadman, D. & Banham, A. 2014. Bringing groundwater models to LIFE: a new way to assess water resource management options. Hydrological Sciences Journal, 59, 1-16.