Outcomes of a West Thames seasonal hydrological forecasting focus group

Jess Neumann
IMPREX Early Career Scientist

Jessica Neumann, Louise Arnal, Rebecca Emerton, Helen Griffith, Sofia Theofanidi & Hannah Cloke

On 6th November 2017, a focus group on seasonal hydrological forecasting (SHF) in the West Thames was held at the University of Reading. The day focused on participant knowledge exchange and sharing of ideas: we introduced participants to current SHF products, initiatives and projects in the UK and Europe, engaged with their experiences, explored how SHF is being applied in the West Thames and identified barriers to use and opportunities for the future.

The focus group was co-organised by the University of Reading and Environment Agency and supported by the IMPREX project (www.imprex.eu) and European Centre for Medium Range Weather Forecasts (ECMWF).












About the West Thames

The West Thames refers to the non-tidal portion of the Thames River basin (UK). It comprises 10 sub-basins that extend from the source of the River Thames in rural Gloucestershire to the outskirts of Greater London (Fig. 1).

The upper reaches (west) are dominated by agricultural land and underlain by chalk and sandstone aquifers. Towards London, the landcover becomes increasingly urbanised and the clay geology is less permeable.

There is a high demand for water resources across the West Thames and the region is subject to flood and drought risk.

Location of the West Thames

Fig. 1. Location of the West Thames 


Who took part?

11 participants from research, policy and practice who represented flood and drought forecasting, water resource modelling, public water supply, waste water operations, navigation and groundwater hydrology.

10 were local to the West Thames, all were familiar with the concept of SHF and 10 currently use SHF in their organisations (Fig. 2).

Figure 2. indication of SHF use in the West Thames water sector

Fig. 2. Indication of SHF use in the West Thames water sector (participants provided multiple details so graphs do not represent individual responses).


What is understood by seasonal hydrological forecasting (SHF)?

We were interested to explore what participants understood of SHF. We used open discussion to capture varying perspectives, definitions and ideas about why (and who) should implement SHF.

What is SHF? Prediction of river flows and groundwater levels using seasonal meteorological forecasts (and other methods) at a timescale of 1 – 3 months, out to 6 months.

How is SHF different? Longer forecast duration, greater uncertainty, coarser spatial and temporal resolution, uses different methods, creates scenarios and poses questions.

Organisations and users? Application and benefits extend from local communities up to Government level; sectors include agriculture, transport, tourism and the economy. Users include water utility companies, local authorities, insurance providers, Government Agencies and research institutions.

Word Cloud

Fig. 3. Why should we implement SHF? For better preparedness, decision-making, mitigation and response to upcoming (extreme) hydrological situations.


SHF for early-warning and effective decision-making at the local level? Results from a decision-making game:

The inability for SHF to assist in local-scale decision-making and action is recognised as a key barrier to use. Using progressively skilful and locally tailored ‘hypothetical’ SHF (for a flood event with 3 months lead time), we asked participants to discuss and make informed decisions across the West Thames sub-basins.

Blue: Decide there’s no notable risk: do nothing currently
Green: Identify potential risk: agree to keep an eye on the situation
Yellow: Identify potential risk: actively request further information
Red: Identify potential risk: set in motion action(s) in a basin

Key findings:
  • Participants increased their decision/action choice in response to more skilful forecasts.
  • Local knowledge and experience of previous flood events were very important for informing decisions e.g. basin hydrogeology and public risk of flooding.
  • Flood forecasters and groundwater hydrologists were most likely to request further information about a potential flood situation, inform other organisations and implement actions for preparedness e.g. maintenance to flood defences, press releases and strategic planning.
  • Water resource managers more consistently adopted a ‘watch and wait’ approach whilst communicating with other partners. They recognised both benefits to public water supply and the potential risks to water quality posed by flooding.
  • Participants valued having a range of complementary forms of SHF information including maps, hydrographs and text.
  • All participants wish to be kept informed of the developments in scientific research, particularly how forthcoming potential improvements to SHF could translate into effective early-warning and decision-making at local scales (see 1 and 2 below).
Response Stage 1.jpgResponse Stage 3.jpg

Fig. 4. Decisions taken based on (top) least skilful and (bottom) most skilful SHF information for the West Thames. 


What is happening in SHF research and development?

The scientific community is responding to society’s call for more actionable research which places emphasis on engaging with stakeholders and providing information to guide business and policy decisions.

Asking questions…

“When are forecasts good enough?”

“How should we present information?”

Identifying barriers and exploring opportunities…

Supporting operational seasonal forecasts…

Figure 5. Overview of some current SHF projects and their objectives

Fig. 5. Overview of some current SHF projects and their objectives


Barriers to using SHF – what users need now and what they want for the future:

1. Skill & uncertainty - “This is one for the research community!”
A better understanding of the interactions between rainfall, rivers, soil, groundwater and sewers.

2. Data access - “We need better access to regional data (not just UK-wide)”
We need the ability to blend short and long-range forecasts together and collaboration of open data.

3.  Communication - “Non-technical guidance so forecasts don’t get misrepresented”
Better communication between partners/ sectors and understanding of risk, probability and uncertainty.

The future: Everyone working with standardised, real-time data of seamless spatio-temporal coverage and using the same tools to generate user-tailored outputs that produce collaborative and consistent messages.



There is good awareness of SHF in the West Thames and current use by the local water sector is greater than what was expected. The way stakeholders approach and use SHF information differs depending on the nature of the event and their role in the water sector. However, all participants recognised that clearer communication is needed – both in terms of forecast interpretation and between partner organisations to ensure that risks are fully understood and decisions and actions are made effectively and collaboratively.


Take-home messages

1. The importance of local knowledge and experience for decision-making must not be underestimated.
2. Updates and information about developments in scientific research need to be shared more widely.
3. Better communication and collaboration is needed between all water sector partners.


Want to know more? A detailed version of the focus group activities and findings will shortly be published as a report and scientific document. If you would like to find out more about our research you can contact Jess Neumann j.l.neumann@reading.ac.uk, Louise Arnal louise.arnal@ecmwf.int or Hannah Cloke h.l.cloke@reading.ac.uk.


Research cited:

1. Neumann et al. (2018) The 2013/14 Thames basin floods: Do improved meteorological forecasts lead to more skilful hydrological forecasts at seasonal timescales? Journal of Hydrometeorology (in press)
2. Arnal et al. (2018) Skilful seasonal forecasts of streamflow over Europe? Hydrol. Earth Syst. Sci. 22, 2057-2072




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