<h6 id="General-DefinitionsOfTheQualityFlags-Created:19November2018Updated:30March2023"><strong>Created</strong>: 19 November 2018   <strong>Updated</strong> : 30 March 2023</h6><p>The following flags are used on the website to describe the quality of the flow data.<strong> </strong></p><p><strong>Good</strong> – the data has been manually inspected and there are no obvious or known data issues.</p><p><strong>Estimated</strong> – a manual change has been made to the data with confidence.</p><p><strong>Suspect</strong> – a change cannot be made but the data is felt to be inaccurate.</p><p><strong>Unchecked</strong> – raw input data that has not been inspected manually.</p><p><strong>Missing</strong> – data has been deleted or never arrived in the archive.</p><p><strong>Percent valid</strong> – the percentage of 15 min (instantaneous) flow data available to calculate the daily mean.</p>

General - Definitions Of The Quality Flags

<h6 id="General-HowAccurateIsTheData?-Created:15November2018Updated:30March2023"><strong>Created</strong>: 15 November 2018   <strong>Updated</strong>: 30 March 2023</h6><p>We work hard to provide you with accurate information. Because the measurements are sent straight to our website they are initially unchecked and may occasionally be incorrect. There may also be occasions when data will not have been downloaded from a monitoring station; and results will therefore not appear on our website until the next time data is collected. If there are persistent problems with incorrect or missing data we may temporarily suspend a site until the issues have been resolved. After a period of time the data is checked for plausibility by a hydrometric expert. During the check the expert will label the data with one of our quality flags.</p><p> This can result in changes to long periods of data. It is therefore recommended that you download the full time period you are interested in each time before you undertake any analysis. </p><p> Whilst every effort has been made to ensure the accuracy of the information provided, neither the Environment Agency, nor its employees or agents can be held responsible for any inaccuracies or omissions, whether caused by negligence or otherwise.</p>

General - How Accurate Is The Data?

<h6 id="General-HowCanIDownloadTheData?-Created:20November2018Updated:30March2023"><strong>Created</strong>: 20 November 2018   <strong>Updated</strong>: 30 March 2023</h6><p>Once you have selected the site you are interested in on the map click on the ‘download data’ tab on the right to download the data in a csv format.</p><p>A direct link to the Hydrology data is here: <a class="external-link" href="https://environment.data.gov.uk/hydrology/explore" rel="nofollow">Hydrology Data Explorer</a></p><p>You can also automate a download for multiple sites as the data is available through an Application Programming Interface (API).</p><p>This enables users to write computer code to access the data. A direct link to the Hydrology API data is here: <a class="external-link" href="https://environment.data.gov.uk/hydrology/doc/reference" rel="nofollow">Hydrology API data</a> </p>

General - How Can I Download The Data?

<h6 id="General-HowOftenIsTheHydrometricDataUpdated?-Created:15November2018Updated:30March2023"><strong>Created</strong>: 15 November 2018   Updated: 30 March 2023</h6><p>The frequency of the updates is site specific, depending on the equipment at the site, how often there is an internet or phone signal at the site and how our software is configured.</p><p>Updates will vary from every 15 min through to monthly (except for manually dipped boreholes) a couple of times per year. Below are some rules of thumb but these will not apply to every site.</p><p>River flow (m<sup>3</sup>s<sup>-1</sup>):<br/>A) several times per day: updates from telemetry (15 min data) for stations in Wessex and Devon and Cornwall.<br/>B) daily: updates of daily mean values from the EA’s hydrometric archive<br/>C) monthly: updates of 15 min data, day max and day min for all flow sites.</p><p>River level (m):<br/>A) several times per day: updates from telemetry (15 min data).<br/>B) monthly: updates of 15 min data, day max and day min from the EA’s hydrometric archive</p><p>Rainfall (mm):<br/>A) several times per day: updates from telemetry (15 min data).<br/>B) daily: updates of daily totals from the EA’s hydrometric archive<br/>C) monthly: updates of 15 min data from the EA’s hydrometric archive</p><p>Groundwater (mAOD):<br/>A) several times per day: updates from telemetry for some stations (15 or 60 min data)<br/>B) weekly: updates of dipped data from the EA’s hydrometric archive<br/>C) monthly: updates of high-resolution data from the EA’s hydrometric archive</p><p />

General - How Often Is The Hydrometric Data Updated?

<h6 id="General-IHaveAnAbstractionLicence.CanIUseThisInformation?-Created:20November2018Updated:30March2023"><strong>Created</strong>: 20 November 2018   <strong>Updated</strong>: 30 March 2023</h6><p>Yes this flow information can be used by abstractors to help manage your abstraction. However, the information included in this service does not replace or affect the legal (paper) copy of the licence issued to you. The information must be used for reference only. You must refer to and comply with the licence issued to you. <strong>In other words you should continue to use your current monitoring methods to make abstraction decisions. </strong>Flow information relevant to your licence will soon be available on view my licence (<a class="external-link" data-card-appearance="inline" href="https://www.gov.uk/guidance/manage-your-water-abstraction-or-impoundment-licences-online" rel="nofollow">https://www.gov.uk/guidance/manage-your-water-abstraction-or-impoundment-licences-online</a> ). If you would like further information or data please email us at <a class="external-link" href="mailto:enquiries@environment-agency.gov.uk" rel="nofollow">enquiries@environment-agency.gov.uk</a> or phone us on: 03708 506 506 (Monday to Friday, 8am to 6pm).</p>

General - I Have An Abstraction Licence. Can I Use This Information?

<h6 id="General-IsAllTheHydrologicalDataRecordedInGMT?-Created:30March2023Updated:30March2023"><strong>Created</strong>: 30 March 2023   <strong>Updated</strong>: 30 March 2023</h6><p>Yes, all data is recorded in Greenwich Mean Time (GMT). This means during British Summer Time (BST) data will appear to be an hour older than you would expect.</p>

General - Is All The Hydrological Data Recorded In GMT?

<h6 id="General-WhatIsAWaterDay?-Created:30March2023Updated:30March2023"><strong>Created</strong>: 30 March 2023   <strong>Updated</strong>: 30 March 2023</h6><p>All our daily data (mean, max, min and total) are calculated over a water day. This is from 9am GMT one morning through to 8.59am GMT the following day. For example, the day mean on the 1st January is the average of all the 15 min values from 09:00 1st January to 08.59 2nd January.</p>

General - What Is A Water Day?

<h6 id="General-WhatIsSub-DailyData?-Created:30March2023Updated:30March2023"><strong>Created</strong>: 30 March 2023   <strong>Updated</strong>: 30 March 2023</h6><p>Sub-daily data is our high-resolution data and is usually collected every 15 min (although for some boreholes it can be every 60 min). Our sub-daily data will have up to 96 values per day and is used to calculate the daily data (mean, min, max or total).</p>

General - What Is Sub-Daily Data?

<h6 id="General-WhatIsTheDifferenceBetweenCheckedAndUncheckedData?-Created:19November2018Updated:30March2023"><strong>Created</strong>: 19 November 2018   <strong>Updated</strong>: 30 March 2023</h6><p>Unchecked data has not been reviewed, it has been recorded at the gauging station and transferred straight to the website. Checked data has been through a plausibility check by the hydrometry and telemetry team at the Environment Agency and is deemed to be the best available. During the check the expert will label the data with one of our quality flags outlined below. Please note that the checked data can still be revised. We recommended that you download the full time period you are interested in each time before you undertake any analysis, so that any revised data is included. </p>

General - What Is The Difference Between Checked And Unchecked Data?

<h6 id="Groundwater-WhatDoesMAODMean?-Created:09September2020Updated:30March2023"><strong>Created</strong>: 09 September 2020   <strong>Updated</strong>: 30 March 2023</h6><p>mAOD= Meters above ordnance datum. This gives the actual elevation of the groundwater level referenced to the mean sea level at the UK Ordnance datum at Newlyn, Cornwall. All elevations in the UK are derived from this datum.</p>

Groundwater - What Does MAOD Mean?

<h6 id="Groundwater-WhatIsBoreholeDepth?-Created:09September2020Updated:30March2023"><strong>Created</strong>: 09 September 2020   <strong>Updated</strong>: 30 March 2023</h6><p>Borehole depth is the depth of the borehole from the datum to the base of the borehole. This should be deep enough such that there is still water in the borehole even in extreme drought.</p>

Groundwater - What Is Borehole Depth?

<h6 id="Groundwater-WhatIsTheDifferenceBetweenDipped,LoggedAndTelemeteredData?-Created:09September2020Updated:30March2023"><strong>Created</strong>: 09 September 2020   <strong>Updated</strong>: 30 March 2023</h6><p><strong>Dipped Data </strong>- a measurement of the depth of groundwater below a surface datum recorded manually e.g. by means of a dip tape. Usually recorded on a monthly basis.</p><p><strong>Logged Data </strong>- continuously monitored groundwater level data recorded by means of a pressure transducer. Data is accessed either by downloading to a computer when the site is visited or remotely via telemetry.</p><p><strong>Telemetered Data</strong> - data recorded with a logger and accessible in real time by means of remote access e.g. via an internet link.</p>

Groundwater - What Is The Difference Between Dipped, Logged And Telemetered Data?

<h6 id="Groundwater-WhyAreThereSometimesDifferencesBetweenDippedAndGroundwaterTelemeteredDataAtTheSameSite?-Created:09September2020Updated:30March2023"><strong>Created</strong>: 09 September 2020   <strong>Updated</strong>: 30 March 2023</h6><p>Recent telemetered data has not been quality assured. Logged data drifts over time and needs to be re-calibrated by undertaking a manual dip and adjusting the logged data accordingly. There may also be other corrections such as spikes or infill of missing data to be made. Therefore recent telemetered data values may be altered as part of the QA process and caution should be taken when viewing this data.</p>

Groundwater - Why Are There Sometimes Differences Between Dipped And Groundwater Telemetered Data At The Same Site?

<h6 id="Rivers-IsRiverFlowAlwaysAFunctionOfRiverLevel?-Created:20November2018Updated:30March2023"><strong>Created</strong>: 20 November 2018   <strong>Updated</strong>: 30 March 2023</h6><p>As flow is a function of river level and velocity it is possible to get different values of flow for the same level. This can happen if the characteristics of a river channel, for example, the shape or roughness of the channel, change as the result of a flood or from the growth of vegetation. Most level monitoring sites are located in relatively stable stretch of river to help minimise this.</p>

Rivers - Is River Flow Always A Function Of River Level?

<h6 id="Rivers-ThereAreDifferencesBetweenTheDataAvailableOnTheEnvironmentAgency’sWebsiteAndTheNationalRiverFlowArchive,WhichTimeSeriesShouldIUse?-Created:20November2018Updated:30March2023"><strong>Created</strong>: 20 November 2018   <strong>Updated</strong>: 30 March 2023</h6><p>We work closely with the National Flow Archive to ensure the daily flow data we provide them with is the same as we hold in our archive. Over time there is a risk that there may be small differences for a small percentage of records at a few sites. The Environment Agency will regard its <strong>daily flow data</strong> as correct unless there is evidence to prove otherwise.</p><p>Note that the <strong>NRFA Peak River Flow dataset</strong> is to be used as the primary source for <strong>flood peak data</strong>. The stations selected for the NRFA have been subject to further analysis for peak flow quality assessment including additional peak flow data that pre-dates the Environment Agency’s digital the EA’s hydrometric archive (WISKI database), consequently, some stations in the Hydrology Data Explorer have peak flow data that currently differ from that in the NRFA.</p>

Rivers - There Are Differences Between The Data Available On The Environment Agency’s Website And The National River Flow Archive, Which Time Series Should I Use?

<h6 id="Rivers-WhatIsTheDifferenceBetweenRiverLevelAndRiverFlow?-Created:20November2018Updated:30March2023"><strong>Created</strong>: 20 November 2018   <strong>Updated</strong>: 30 March 2023</h6><p>River level is the depth of water at a monitoring station, measured in metres relative to a specified datum. Flow is the volume of water passing a monitoring site over a given time, measured in cubic metres per second. Details of the datum level for a river level site are available by following the link to the Check for flooding in England on the station page <a class="external-link" data-card-appearance="inline" href="https://check-for-flooding.service.gov.uk/find-location" rel="nofollow">https://check-for-flooding.service.gov.uk/find-location</a> </p>

Rivers - What Is The Difference Between River Level And River Flow?

<h6 id="Rivers-WhyDoRiverLevelsOrFlowSometimesIncreaseOrDecreaseUnexpectedly?-Created:20November2018Updated:30March2023"><strong>Created</strong>: 20 November 2018   <strong>Updated</strong>: 30 March 2023</h6><p>Rivers increase and decrease in response to how much rain falls. However, some rivers are also affected by other factors such as: the opening and closing of sluice gates, reservoir releases and the influence of tides.</p>

Rivers - Why Do River Levels Or Flow Sometimes Increase Or Decrease Unexpectedly?

<h6 id="Rivers-WhyIs15Minute(Instantaneous)FlowDataOnlyAvailableForASmallNumberOfStations?-Created:19November2018Updated:30March2023"><strong>Created</strong>: 19 November 2018   <strong>Updated</strong>: 30 March 2023</h6><p>The 15 minute data comes directly from our telemetry systems and only a small number of sites are set up to calculate 15 min flow data. For the vast majority of sites the raw level data is transferred to our archiving software which then calculates the flow data. </p>

Rivers - Why Is 15 Minute (Instantaneous) Flow Data Only Available For A Small Number Of Stations?

<h6 id="Rivers-WhyIsReal-TimeFlowDataOnlyAvailableForASmallNumberOfStations?-Created:30March2023Updated:30March2023"><strong>Created</strong>: 30 March 2023   <strong>Updated</strong>: 30 March 2023 </h6><p>The real-time data comes directly from our telemetry systems and only a small number of sites are set up to calculate 15 min flow data (primarily across Devon, Cornwall and Wessex). For the vast majority of sites, the raw level data is transferred to our archiving software which then calculates the flow data. </p>

Rivers - Why Is Real-Time Flow Data Only Available For A Small Number Of Stations?

<h6 id="WaterQuality-HowAccurateIsTheData?-Created:30March2023Updated:30March2023"><strong>Created</strong>: 30 March 2023   <strong>Updated</strong>: 30 March 2023</h6><p>Each day a team of internal data analysts conducts a daily check to ensure that the data being collected is of evidential quality. Calibrations and maintenance of instruments are on a monthly regime to minimise any fouling etc. If any anomalies occur, they are picked up during the daily check and an internal field engineer is sent out to respond as soon as possible.</p>

Water Quality - How Accurate Is The Data?

<h6 id="WaterQuality-HowAreTheWaterQualitySitesSelected?-Created:30March2023Updated:30March2023"><strong>Created</strong>: 30 March 2023   <strong>Updated</strong>: 30 March 2023</h6><p>Environment Agency area teams are allocated a set amount of continuous water quality monitoring units at one time; the locations of which will be decided based on local evidence and investigations. To provide a more complete understanding of water quality in the area, units are often deployed short-term and change location regularly unless a more extensive investigation is required.</p>

Water Quality - How Are The Water Quality Sites Selected?

<h6 id="WaterQuality-HowDoIAnalyseTheData?-Created:30March2023Updated:30March2023"><strong>Created</strong>: 30 March 2023   <strong>Updated</strong>: 30 March 2023</h6><p>NWQIS deliver data training sessions for anyone interested in understanding the data and navigating the website. Please contact <a class="external-link" href="mailto:nwqis@environment-agency.gov.uk" rel="nofollow">nwqis@environment-agency.gov.uk</a> to organise a training session or to join one of the drop-in sessions.</p><p />

Water Quality - How Do I Analyse The Data?

<h6 id="WaterQuality-HowIsTheDataDifferentToTheWaterQualityArchive(WIMS)Data?-Created:30March2023Updated:30March2023"><strong>Created</strong>: 30 March 2023   <strong>Updated</strong>: 30 March 2023</h6><p>This data is showcasing continuous water quality monitoring of units deployed for an extended period of time, whereas WIMS mainly consists of spot samples taken by individuals in the area teams.</p>

Water Quality - How Is The Data Different To The Water Quality Archive (WIMS) Data?

<h6 id="WaterQuality-HowOftenDoWeTakeReadings?-Created:30March2023Updated:30March2023"><strong>Created</strong>: 30 March 2023   <strong>Updated</strong>: 30 March 2023</h6><p>Usually, readings are taken every hour. However, there may be some sites that are set to 15- or 30-minute intervals depending on the nature of the investigation. For instance, if investigating responses to storm events, we may decide to temporarily change the sampling interval to 15 minutes.</p>

Water Quality - How Often Do We Take Readings?

<h6 id="WaterQuality-WhatWaterQualityDataIsAvailable?-Created:30March2023Updated:30March2023"><strong>Created</strong>: 30 March 2023   <strong>Updated</strong>: 30 March 2023</h6><p>Non-commercial sites that are not currently sub judiciary and that are granted permission by the internal customer requesting the equipment can be made available to the public.</p>

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Water Quality - How Do I Analyse The Data?

Created: 30 March 2023 Updated: 30 March 2023