Catchments and Points

What do I get when I buy a catchment?
  • all catchment descriptors, exportable in CD3/XML/CSV format, including FEH13 rainfall data that can be used with ReFH 2.1+. The descriptors are: Area, Altbar, Aspbar, Aspvar, Bfihost, Bfihost19, CentroidEasting, CentroidNorthing, Dplbar, Dpsbar, Farl, Fpext, Fpdbar, Fploc, Ldp, Propwet, Rmed1H, Rmed1D, Rmed2D, Saar6190, Saar4170, Sprhost, Urbconc1990, Urbext1990, Urbloc1990, Urbconc2000, Urbext2000, Urbloc2000, FEH99 model parameters (CatchmentRainC, CatchmentRainD1, CatchmentRainD2, CatchmentRainD3, CatchmentRainE, CatchmentRainF, GridRainD1, GridRainD2, GridRainD3, GridRainC, GridRainE, and GridRainF).
  • a high-resolution catchment boundary in ESRI shapefile format
  • unlimited rainfall depth/duration/rarity (DDF) calculations using both the FEH99 and FEH13 models
  • interactive rainfall growth curve graphs
  • bulk export of FEH99 and FEH13 DDF values in CSV format

Once a catchment has been purchased it remains associated with your account granting you perpetual access to the data above.

What do I get when I buy a point (as opposed to a catchment)?

In contrast to an entire catchment, a point is a single location on the map accurate to 1m. With a point you get

  • the BFIHOST, BFIHOST19, SAAR6190, and PROPWET descriptors and FEH13 rainfall data for that point, which can be exported to XML and used with ReFH v2.2+
  • unlimited rainfall depth/duration/rarity (DDF) calculations using the FEH13 model
  • interactive rainfall growth curve graphs
  • bulk export of FEH13 rainfall DDF values in CSV format

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.

BFIHOST19 - why has the BFIHOST descriptor being updated?
BFIHOST is a catchment descriptor that provides an estimate of base flow index (BFI). It is derived from the Hydrology of Soil Types (HOST) classification which provides a measure of catchment responsiveness. The HOST dataset is a 1km grid that records the percentage of each soil class present. The BFIHOST catchment descriptor is an area-weighted value derived from grids located within the delineated catchment boundary. BFIHOST is used with other variables to estimate the median annual maximum flood in the FEH statistical method and the maximum soil moisture capacity parameter in the ReFH2 loss model. A number of issues with the BFIHOST catchment descriptor values had been identified, including a tendency to underestimate BFI in clay-dominated catchments, problems in ephemeral catchments and an error in referencing 1km point BFIHOST which was identified and corrected during 2018. To resolve such issues, UKCEH has revised the regression method used to estimate BFIHOST and has improved the classification of rare soil types. The new BFIHOST19 values for catchments and 1km points is now available alongside the original BFIHOST data. The catchment descriptor equations that include BFIHOST are being reviewed and recalibrated as required to allow the improved data to be used in flood frequency estimates. The latest FEH rainfall-runoff method (ReFH2.3) uses the BFIHOST19 descriptor.

Educational Users

I am an educational user: what discounts apply?
A discounted rate is available for educational use. The cost is £150 (excluding VAT) for 1,000 credits (£1.50 per catchment retrieval). The Organisational account feature is not available for Educational use as the credits must all be released to the same Web Service account and used by the agreed licensee. If you qualify for this offer we will issue you with a licence certificate along with an invoice for payment (we do not accept credit/debit card payments for educational licenses). The signed licence certificate and payment must be received before the credits are allocated. Please visit the Contact Us page to proceed set up.

FEH Methods

How can I access the Flood Estimation Handbook?

A free downloadable version is available:

You can purchase a hardcopy via Wallingford HydroSolutions on behalf of UKCEH.
What is the uncertainty in the FEH Methods?
A short guide has been prepared on the uncertainty in FEH methods.


Background to the Depth-Duration-Frequency (DDF) models and the differences between FEH13 and FEH99
The below UKCEH Webinar provides the background to UK rainfall frequency (DDF) modelling and comparisons between FEH13 and FEH99 rainfall estimates, as well as an introduction to using the FEH Web Service. This can also be viewed on YouTube here.

What is the FEH13 rainfall DDF model?

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:

  • increased availability of rainfall maxima, particularly for sub-daily durations;
  • a revised standardisation that uses average annual rainfall (SAAR) and northing in addition to the index variable RMED (the median annual maximum rainfall) to remove more of the location-dependent variation in rainfall before combining maxima from networks of rain gauges;
  • a revised spatial dependence model;
  • improvements to the FEH FORGEX method of deriving rainfall growth curves using annual maxima pooled from increasingly wider circles as return period increases;
  • a more flexible depth-duration-frequency (DDF) model structure.

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.

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.

What period of data has the FEH13 rainfall been derived from?
The development of the FEH13 DDF model made maximum use of the daily and sub daily rainfall data available across the UK and thus doesn’t conform to a specific period of record. Furthermore, as the DDF model uses the statistics of the observed record to make predictions of extreme value rainfall depths that lie outside of the observed records the concept of a period of record is not really applicable. This argument also applies to the FEH99 and FSR DDF models. However, in the absence of an identifiable trend in rainfall patterns that can be attributed to climate change it is reasonable to use the FEH13 estimates as the baseline for applying climate change factors. This is consistent with the past practice of applying such factors to the FEH99 DDF model estimates.


How do I report a problem, or ask for help?
Please see the Contact Us page.
Use of the FEH Web Service data with ReFH 2 software

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.

"Save map as image" does not work (Internet Explorer and Safari)
Internet Explorer version 11 (as well as versions 9 and 10, and Safari) will prevent you from using the "Save map image" function. The simplest solution is to use the Chrome or Firefox browsers. As a workaround you can use Windows' built-in screen capture function: hold down the Windows key and press PrtScn. Alternatively, use the Snipping Tool utility in Programs -→ Accessories. Mac users should use Command-Shift-4. This will take a copy of the screen which you can paste into Word or your favourite image editing software.
What web browsers are supported?
We aim to support the newest versions of Microsoft Edge, Firefox and Chrome. Internet Explorer version 11 is no longer recommended. The Safari browser will prevent you from using the "Save map image" function. See the separate FAQ on this topic. Older versions of Safari also have problems with data entry fields. If you have problems entering numeric values we recommend you switch to to one of the fully-supported browsers, above.

Individual Users

What is an individual user account?
As an individual user, you can buy and spend credits as you wish and you are not linked to other user accounts. To sign up as individual please register here.

Lead Users

What is the role of lead users?
They are responsible for purchasing credits for the organisation and allocating them to users. They can invite colleagues to join the organisational account. They will also be able to download a usage report showing which point and catchments have been exchanged for credits, by whom, and when.
How do I become a lead user of an existing organisational account?
You will need to ask the existing lead user(s) and they will invite you to become an additional lead user.
As lead user, how do I invite other colleagues to join my organisation?
Under 'Manage Account' click on 'Add new member', enter their details and they will be sent a notification email, which will contain a link that they will need to click on to complete the set up process. For security reasons this link must be used within 48 hours of issuing; please take this into account and time the invitation accordingly.
How do I invite other colleagues to join my organisation and also invite them to become a lead user?
Follow the same steps as above, and when your entering their details there is a tick box to select organisational lead user. Tick this to give them lead user permissions. Existing lead users can provide lead user permissions to any user in your organisation.
As lead user how do I adjust the quota for organisational users?
When logged in as the lead user, under the ‘Your Account’ menu, → ‘Manage organisation and orders’ you will see the organisation users listed and their current quota. If you click on their name and then ‘edit’ you can adjust their credit quota and click save.
How should the lead user allocate credits?
There are a few approaches that could be taken:

1. Allocate an equal quota to all users up to the total value of credits available. For example if you had a total of 1,000 credits and 4 users, you could allocate 250 credits per each user. You can adjust this up and down for each user as and when the credits are used.

2. Set every user in the account with a large quota, higher than the available credits. Then users are free to purchase data to the limit of the organisational credit balance (i.e. have access to all remaining credits), and it is then the responsibility of you as the lead user to make sure there are enough credits available across the organisation.

3. Ring-fence credits to certain users, or set individual quotas for each user.
As lead user, how can I monitor what data my colleagues have purchased
The lead user has access to a usage report which will show you who has downloaded catchment and point data. When an organisational user purchases catchment or point data they can add a tag the the purchased item; this field is visible in the usage report export so if users are instructed to populate this tag with the project code/ cost centre code you could keep track of data purchased for each project code/ cost centre code.

Map Layers

What are Peak Flow gauging stations, and the Suitable to QMED and Suitable for Pooling categories?
The NRFA Peak Flow Dataset provides peak flow data (Annual Maxima and Peaks over Threshold) for a sub-set of the NRFA gauging stations for which daily flow data are available. The indicative suitability for QMED and Pooling is assigned to each Peak Flow station and relates to the suitability for use within the FEH methods.
What is the ReFH gauging station category?
These are the gauging stations that were used in the development of the ReFH parameter equations, where multivariate regression analysis was used to relate the variation in calibrated model parameters (Tp, Cmax, BL and BR) between catchments to catchment descriptors. There are separate sets of parameter equations for Scotland and the group of England, Wales and Northern Ireland.

Organisational Accounts

What is an organisational account?

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.

My company has an organisational account for the Web Service; how do I join it?
You will need to ask a lead user to invite you to join the organisational account.
I am an existing user and I have been invited to join an organisational account. What will happen to my existing credit balance?
Your credits will be merged into a single organisational balance, and it will be the responsibility of the lead user to assign you a credit quota.
How are credits allocated under the organisational account?
It will be the responsibility of the lead user to allocate a credit quota to each user. Your balance of credits will be the quota amount.
How many credits does my organisation have?
The credit box in the top hand right corner of the page shows your organisation balance. Balances over 1000 are simply shown as 1000+. Lead users can see the exact amount via the "Your account → Manage organisation and users" menu
My company has multiple organisational accounts; how do we merge them into one?
You will need to contact us to arrange for the accounts to be merged. Within your request please include as much information as possible including the name of each organisational account, the lead users and the lead user you would like to be responsible for the new account.
I am an existing/new Web Service user; can I set up an organisational account with myself as the lead user?
Firstly please check with your organisation; if you find out an organisational account already exists please visit the FAQ - I have been informed that my company has an organisational account for the Web Service; how do I join it? Or - How do I become a lead user of an existing organisational account? Otherwise please contact us to set up a new organisational account.
Can I set up an organisational account with two lead users?
You should follow the above FAQ; initially, organisational account must be allocated a single lead user. As soon as the lead user account is created they can then invite others to join and become lead users.

Organisational Users

What is an organisational user account?
As an organisational account user you will have access to all catchment and point data purchased by all users within your organisational account. Lead user(s) will be nominated by the organisation and will be responsible for purchasing credits for the organisation and allocating them to the organisational users. To become an organisational user, either your organisation will already have an organisational account set up or a lead user will need to be nominated to arrange for set up. Please visit the FAQ - I am an existing/ new Web Service user and would like to set up an organisational account with myself as the lead user?
My quota is showing 0, how do I request more credits?
You will need to speak to your lead user(s) to request for more credits. The lead users' email are listed under Your Account → Profile, on the Overview tab.
How can I distinguish between my purchased catchments and points and those purchased by other users in my organisation?
On the expandable menu on the left side of the map page please click on 'My Catchments' and 'My Points' to view the catchments and points that you have purchased. Catchments will appear as green on the map and Points will be shown in brown. If you are an organisational account user, you can click on either 'Shared Catchments' or 'Shared Points' and they will be visible on the map in grey. These will be the points and catchments purchased by other users within your organisation. If you then click on these to view the data you will not be asked to purchase this as it has already been bought. You can then choose to rename the items by editing the description. This new name will be private to you and not affect names assigned by other colleagues.
When purchasing a catchment or a point you have the option to enter a tag; what is this for?
The tag field for each purchased catchment or point can, for example, be used for project/team codes. These will appear in the details on your purchased catchment or point and within the usage report the lead user can download allowing credit expenditure to be costed to projects or teams.

Purchasing Credits

What are the payment options?
The credit purchase process is the same for individual users and lead organisational users. Under your account click on the option 'Purchase Credit' and enter the amount you wish to purchase. A purchase of up to 1,000 credits can only be made via credit or debit card though our secure payment gateway. Alternatively for orders over 1,000 credits you have the option to select 'Purchase Order' and payment can be made via bank transfer or cheque. You are given the option to enter a PO number and the system will then issue you a proforma invoice. Once payment is received credits will be allocated to your account and you will be notified via email.

Bulk credit purchases for 10,000 or above payment must be paid via purchase order.

How much do credits cost?
Please visit the Pricing page.
How do I pay by credit/debit card?
Under your account click 'Buy Credit' and simply add the quantity of credits you wish to purchase (to pay by credit/ debit card you can purchase up to 10,000 credits) and you will be provided with a total price. Click ‘Checkout’ and you will be asked to enter your billing information. You will be taken to the order confirmation where you can then ‘Proceed to Card Payment’. Once payment has been made, your credits will automatically be assigned to your account.
How do I pay by purchase order?
Purchase order payments can either be made via bank transfer or cheque. Under your account click 'Buy Credit' and simply add the quantity of credits you wish to purchase (to pay by purchase order you have to buy 1,000 or more) and you will be provided with a total price. Click ‘Checkout’ and you will have the option to select ‘Payment Method: Purchase Order’. Complete the details, where you can enter a purchase order number and click ‘Proceed’. You will then be taken to the order confirmation where you can ‘Request Pro Forma Invoice’. On the following page there will be a link to enable you to print your pro forma Invoice, please pass this to your accounts department for payment. Payment can be made via cheque or bank transfer (payment details are detailed on the pro forma). Once payment is received your credits will be allocated and you will be notified via email.
I have placed an order via purchase order but realised that the details on my proforma invoice are incorrect, what should I do?
You will need to cancel the order via your account, place the order again with the correct details.
Can I get a refund if I purchase an incorrect catchment or point?
We cannot offer a refund if a catchment/point is purchased in error. The FEH Web Service has been designed specifically to provide users with as much contextual information as possible, including OS data and the defined catchment boundary, before committing to make a purchase in order to minimise the possibility of errors occurring. We do welcome feedback on the service so if you have any suggestions of additional information that could have been supplied in order to avoid this type of error in the future we would welcome this so that we can feed this into discussions on the future development of the service.
Do my credits expire?

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.