Invasive species and water resources: developing the evidence base for effective mitigation to prevent the spread of invasive non-native species through water transfer networks

Invasive Non Native Species (INNS) cost the UK over £2bn pa and are an increasing threat to aquatic biodiversity and ecosystems. For example, zebra mussels block pipes and reduce drinking water quality, floating pennywort clogs river intakes and increases flood risk, signal crayfish are driving the extinction of the native white clawed crayfish.
Changing climate and demography is placing increasing need on Water Service Companies (WSCs) to balance water supply and demand, hence the transfer of raw water across river and catchment basins is essential to ensuring water supplies. Yorkshire Water (YW) is one of 26 regional and local WSCs in the UK with a statutory duty to provide a constant supply of safe drinking water. Water transfers are critical to the YW business: by balancing demand across their supply network, YW are provide 1.3 billion litres of water a day to their customers.
Accidental translocation of animals or plant fragments during water transfers can lead to the spread of INNS to new rivers or reservoirs. Critically, the likelihood of invasion of a new water body and subsequent ecological impact depends on the number of INNS individuals introduced. Hence, the aim of this studentship is to develop and test new mitigation practices to reduce the spread of INNS during bulk water transfers, focussing on key aquatic animal and plant INNS identified by the Environment Agency (EA) and the UK water industry. The student will receive interdisciplinary training in INNS biology, ecology and water engineering to develop solutions for the water industry.The outcomes of the project will protect the environment by helping water companies guard against the spread of harmful INNS and will feed into company business plans as well as future DEFRA policy and EA regulation.

OBJECTIVES
1. Test potential new mitigation measures to reduce INNS density in water transfers..
i. Changes to source water abstraction depth. INNS plants and animals live at different depths, and some INNS show daily or seasonal migration patterns in the water. The student will explore INNS distribution and compare the numbers of INNS in water sourced from different take-off depths.
ii. Timing and source of supply to bulk water transfer network. Using existing data on seasonal INNS growth and reproduction and YW INNS distribution maps, the student will test the effectiveness of avoiding affected water sources at high risk times of the year.
2. Investigate the viability of bringing existing water treatment unit processes upstream in the treatment chain from receptor to source.
i. Test the effectiveness of screening and sand filters in INNS removal and their impact on water quality and flow
ii. Test the effectiveness of chemical measures (ozone and chlorine) in killing INNS.
APPROACH. A range of approaches will be used including GIS modelling to explore the distribution of INNS; laboratory testing of treatments to remove INNS; field based trials and monitoring.

TRAINING. The project crosses ecological and engineering disciplines and will provide the student with the interdisicplinary training in academic and applied skills in both disciplines to practices required to provide safe drinking water whilst reducing the ecological and economic impact of INNS. At the University of Leeds, they will be jointly supervised by AD and MT. With AD’s research group, they will receive training in INNS ecology and in biosecurity treatments. With MT’s research group they will receive training in lab and field approaches to measure the impact of potential INNS mitigation on water quality, water flow and the security of water transfers. The student will spend up to 10 months with YW, who have extensive experience of supervising PhD students and offer a supportive environment to enabling the student to fulfil their project aims, undertake professional development and improve their career prospects.

IMPACT. The project places environmental science and water engineering at the heart of responsible management of natural resources. It will lead to publications in high quality scientific journals and inform YW operational practice. Societal impact includes ensuring safe water supply and benefits to biodiversity and ecosystems processes through the prevention of the spread of INNS.