Once a catchment has been purchased it remains associated with your account granting you perpetual access to the data above.
In contrast to an entire catchment, a point is a single location on the map accurate to 1m. With a point you get
The FEH99 DDF parameters (C, D1..3, E & F) are not available for points
Once a point has been purchased it remains associated with your account granting you perpetual access to the data above.
A free downloadable version is available:
The FEH13 rainfall model is the FEH’s latest UK-wide statistical model for rainfall depth-duration-frequency (DDF) estimation. The model is based on an analysis of over 170,000 station-years of data from daily rain gauges throughout the UK, together with about 17,000 station-years of hourly data. It was developed to allow the estimation of rainfall depths falling over durations from 1 hour to 192 hours (8 days) for return periods ranging from 2 years to over 10,000 years. The FEH13 model has been extrapolated to provide depth estimates for durations as short as 5 minutes and return periods as frequent as 12 months (estimated on the peak-over-threshold (POT) scale). The model can be used to derive design storm inputs for the ReFH2 rainfall-runoff package or to estimate the rarity of observed rainfall events at individual points or over a catchment. The model is widely used for applications such as flood risk assessment, reservoir flood safety appraisal and drainage design throughout the UK.
The FEH13 model retains the basic index-flood approach of the FEH99 model, i.e. the rainfall frequency curve is derived by multiplying an index variable specific to the site of interest by a regionally derived growth curve, but its main advances are:
A key feature of the modelling procedures is the use of local data wherever possible. Data from smaller networks of rain gauges are used to estimate the frequency curve for shorter return periods, while more spatially extensive networks are drawn into the analysis to define the frequency characteristics for longer return periods. The final FEH13 DDF model was fitted to the outputs from the revised FORGEX procedure at each point on a 1 km grid of the UK for a number of key durations. The model ensures internal consistency in the resulting frequency estimates, i.e. that rainfall depths for any duration increase with increasing return period, and that rainfall depths for any return period increase with increasing duration. It also allows extrapolation to longer return periods than those estimated for the rarest events in the calibration dataset. The model is based on a weighted total of two gamma distributions, each of which is parameterised by duration-dependent equations intended to minimise the difference between the fitted model curves and the output FORGEX lines. The final step in the modelling procedure is smoothing in space and across durations to avoid inconsistencies in the results.
The FEH13 model was released via the FEH Web Service in 2015 and is based on rain gauge records up to about 2005. The original research was funded by Defra (FD2613) and aimed to develop revised rainfall frequency estimates for the longest return periods of relevance to reservoir spillway safety assessment (Stewart et al., 2013). UKCEH funded the further development and generalisation of FEH13 for the full range of durations (from less than 1 hour to 8 days) and return periods (from 12 months to over 10,000 years). Recent research funded by the Environment Agency and UKCEH has investigated the impact of including more recent extreme rainfall events in the model calibration in a case study of Cumbria (Vesuviano et al., 2021). Record-breaking rainfall events were experienced in the region in November 2009 and December 2015, and these together with other events that led to severe flooding were included in the recalibration of FEH13. The results suggest that extreme events of durations between 2 and 4 days are estimated to have shorter return periods (i.e. to be relatively more frequent) in the recalibrated model than estimated by the original FEH13 model (Vesuviano et al., 2021). However, it is important to recognise that a high level of uncertainty still remains in defining return periods in the hundreds or thousands of years using relatively short observational records.
As part of the FEH Research Programme, UKCEH is currently working on recalibrating the FEH13 model across the UK using more recent rain gauge records for a range of durations. The recalibrated model results will be made available through the FEH Web Service in due course.
References Stewart, E. J.; Jones, D. A.; Svensson, C.; Morris, D. G.; Dempsey, P.; Dent, J. E.; Collier, C. G.; Anderson, C. A.. (2013) Reservoir Safety - Long Return Period Rainfall. Technical Report (two volumes). Project FD2613 WS 194/2/39, Defra/EA FCERM R&D Programme Vesuviano, G., Stewart, E., Spencer, P. and Miller, J. D. (2021) The effect of depth‐duration‐frequency model recalibration on rainfall return period estimates. Journal of Flood Risk Management.
The FEH Web Service has been designed to be compatible with ReFH 2 and therefore purchased catchment and point descriptors can be exported in xml format & loaded directly into the software. ReFH can be purchased from Wallingford HydroSolutions.
With the release of the BFIHOST19 descriptor a new set of exports was added to the FEH Web Service incorporating this new descriptor. The 'Descriptors for ReFH2.3+ (XML)' are required to use the ReFH2.3 model. The 'Descriptors for ReFH2.2 (XML)' can still be used in ReFH2, but use of this data excludes the new functionality available in the ReFH2.3 model.
The new export files are available for new and existing purchases of catchment and point data.
The ReFH technical guide and supporting science reports detail the full scope of the ReFH 2 software.
An organisational account allows you to share a pool of credits among all the users in your organisation, simplifying both the credit purchasing process, expanding the possibility of bulk credit discounts, and giving you greater oversight of how those credits are subsequently used. Catchments or points bought by one member of the organisation are be visible to all the organisation’s members. This encourages collaboration and avoids duplicated purchases.
The map displays an additional layer to show or hide organisational purchases, distinguishing them from data purchased by the current user.
One or more users are designated ‘lead users’ for the organisation, responsible for purchasing credits and allocating them to users. Credits are allocated on a flexible quota basis that allows lead users either to ringfence credits exclusively for certain users, or to adopt a more efficient, non-exclusive, pooled approach, or a combination of the two.
A usage report shows the lead user(s) which point and catchments have been exchanged for credits, by whom, and when. These reports can be exported to Excel for integration with your existing project billing tools. A tag field for each purchased catchment or point supplements the description field. These can, for example, be used for project/team codes. These will appear on the reports (above) allowing credit expenditure to be costed to projects or teams.
Bulk credit purchases for 10,000 or above payment must be paid via purchase order.
If you place orders of less than 10,000 credits, these credits will not expire. Credits that are purchased in blocks above this threshold at the higher discount bands (see the pricing page) expire after one year. See also the bulk order purchasing page.
