Monthly Water Situation Report Yorkshire Area
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Monthly water situation report Yorkshire Area Summary – July 2019 Another unsettled month containing some very heavy, localised storms towards the end of the month. Above average monthly rainfall totals were recorded across Yorkshire. Normal or higher river flows in the Pennine catchments and below normal river flows in the groundwater fed catchments. The soils were wet in the western areas and drier to the east, groundwater levels continued to decrease, and overall reservoir stocks were above the long term average. Rainfall An unsettled month ensured July was very wet across Yorkshire although the second half of the month was considerably wetter, recording 74% to 96% of the total recorded rainfall. The high totals were caused by successions of storm fronts passing through the county, with some producing highly localised, very heavy downpours at the end of the month. Two particularly wet periods occurred between: the 19th July to the 23rd July where 17% to 45% of the month’s total rain fell in localised areas. Significant daily totals occurred on the 19th, 21st, and the 23rd. the 26th July to the 31st July where 37% to 77% of the month’s total rain fell in localised areas. Significant daily totals occurred on the 27th, 28th, and especially on the 30th and 31st. South Yorkshire and West Yorkshire experienced some intense storm over the weekend of the 27th and 28th July. Localised areas around Sheffield recorded 80% to 110% of the monthly long term average (LTA) on Saturday while some locations in the upper Calder catchment recorded 70% to 105% of the monthly LTA on Sunday. Then on Tuesday 30th, Malham Tarn in the upper Aire recorded 85% of its monthly LTA in 12 hours, with a very intense storm hitting the upper Swale catchment. Arkle Town raingauge recorded virtually all of its monthly LTA rain in 1 hour and almost 150% of its monthly LTA in 6 hours. The daily total at Arkle Town raingauge was a little over 100mm, or 158% of its monthly LTA. All catchments received above the LTA monthly rainfall, with the Don and Calder catchments recording around twice the LTA. Soil Moisture Deficit (SMD) Rising SMD occurred through the first half of the month in response to the relatively dry weather. By mid-July, central and eastern Yorkshire was classed as being dry with the rest of the Area being classed as normal. Once the unsettled weather arrived, the SMD started to decline. By the end of the month, the western most Pennine ridge had returned to a wet classification, the north-eastern and southern edges were normal, and central and eastern areas were still within the dry classification. River Flows Within the Pennine fed catchments, river flows declined steadily until the 18th July and the majority of catchments were starting to show flows that were classed as below normal for the time of year. The ensuing rainfall had an immediate impact within the rivers and produced numerous high flow peaks. The end of the month had daily mean flows well above what would normally be expected for the time of year. The upper Swale recorded a significant peak on the 30th July in response to a very intense storm. The fluvial gauge at Reeth, located on Arkle Beck, rose by 1.6m in 1.5 hours and also recorded its highest level from a 21 year record. However, the level was truncated, possibly reaching the bank top and overflowing into the All data are provisional and may be subject to revision. The views expressed in this document are not necessarily those of the Environment Agency. Its officers, servants or agents accept no liability for any loss or damage arising from the interpretation or use of the information, or reliance upon views contained herein. © Environment Agency 2019 surrounding area. Levels on the main River Swale recorded peaks that were lower than the peak level reached in March 2019 although still showed notable rates of rise. Grinton Bridge, on the River Swale immediately downstream of Reeth, rose by 2m in 2 hours while Catterick Bridge, further downstream, rose by 1.8m in 30 minutes. With regards to the monthly mean flow, the Pennine catchments were classed as having normal flows for the time of year or were higher. In the groundwater dominated catchments in the east, declining flows were common. The River Derwent was experiencing below normal river flows at the beginning of July and they slowly declining to notably low flows by the 18th. The flow remained low until the very end of the month before there were signs of rising up into the normal range expected for the time of year. The monthly mean flow for the River Derwent was classed as being notably low for the time of year. Within the upper River Hull, as monitored at Wansford Snakeholm Lock, the flow slowly declined throughout the month and was classed as being below normal until the very last day, which saw an increase into the normal range expected for the time of year. The watercourses of Mires Beck and the River Foulness that flow directly into the Humber Estuary declined steadily, below what would normally be expected for the time of year, until the 18th July before fluctuating in response to the rainfall. Groundwater Levels Magnesian Limestone The groundwater level at Brick House Farm continued to fall below the drought trigger level for the time of year. Millstone Grit The groundwater level at Hill Top Farm was at average levels for the time of year. Sherwood Sandstone The groundwater level in the north of the Sherwood Sandstone had fallen to average or slightly above the average for the time of year. The level in the south of the aquifer as measured at Pincheon Green was below average for the time of year. Corallian Limestone The groundwater levels at Sproxton & East Ness had decreased, remaining close to drought trigger levels. Chalk The groundwater level in the northern area of the aquifer, as monitored at Wetwang, had continued to decrease and was at the drought trigger level for the time of year. At Dalton Estate in the south of the aquifer the groundwater level had decreased to well below average for the time of year. Reservoir Storage The overall reservoir stocks decreased by 5% during the first half of the month although were still above the LTA. They then increased back up by 7% in response to the very wet weather during the second half of the month. Environmental Impact There were 7 abstraction licences that had Hands off Flow (HOF) in force within the Derwent catchment. An additional 124 abstractors were on advance warning notifications although they were still able to abstract. Author: Yorkshire Hydrology All data are provisional and may be subject to revision. The views expressed in this document are not necessarily those of the Environment Agency. Its officers, servants or agents accept no liability for any loss or damage arising from the interpretation or use of the information, or reliance upon views contained herein. © Environment Agency 2019 Rainfall © Environment Agency 2019 Jul-19 Jul-19 Jul-19 Jul-19 Jun-19 Jun-19 Jun-19 Jun-19 May-19 May-19 May-19 May-19 Apr-19 Apr-19 Apr-19 Apr-19 Mar-19 Mar-19 Mar-19 Mar-19 Feb-19 Feb-19 Feb-19 Feb-19 © Environment© Agency 2019 Jan-19 Jan-19 Jan-19 Jan-19 Dec-18 Dec-18 Dec-18 Dec-18 1-Month Period for Dales North Sea Tribs 1-Month Period for Derwent(NE) 1-Month Period for Ure 1-Month Period for Ouse Nov-18 Nov-18 Nov-18 Nov-18 Oct-18 Oct-18 Oct-18 Oct-18 Sep-18 Sep-18 Sep-18 Sep-18 Aug-18 Aug-18 Aug-18 Aug-18 0% 0% 0% 0% 50% 50% 50% 50% 250% 200% 150% 100% 250% 200% 150% 100% 250% 200% 150% 100% 250% 200% 150% 100% rainfall average Below Jul-19 Jul-19 Jul-19 Jul-19 Jun-19 Jun-19 Jun-19 Jun-19 May-19 May-19 May-19 May-19 Apr-19 Apr-19 Apr-19 Apr-19 Mar-19 Mar-19 Mar-19 Mar-19 Feb-19 Feb-19 Feb-19 Feb-19 Jan-19 Jan-19 Jan-19 Jan-19 Dec-18 Dec-18 Dec-18 Dec-18 1-Month Period for Rye 1-Month Period for Wharfe 1-Month Period for Nidd 1-Month Period for Swale(NE) Nov-18 Nov-18 Nov-18 Nov-18 Oct-18 Oct-18 Oct-18 Oct-18 Sep-18 Sep-18 Sep-18 Sep-18 bove average rainfall bove A Aug-18 Aug-18 Aug-18 Aug-18 0% 0% 0% 0% 50% 50% 50% 50% 250% 200% 150% 100% 250% 200% 150% 100% 250% 200% 150% 100% 250% 200% 150% 100% Jul-19 Jul-19 Jun-19 Jun-19 May-19 May-19 Apr-19 Apr-19 Mar-19 Mar-19 Feb-19 Feb-19 © Environment© Agency 2019 Jan-19 Jan-19 Dec-18 Dec-18 1-Month Period for Calder 1-Month Period for Hull and Humber Nov-18 Nov-18 Oct-18 Oct-18 Sep-18 Sep-18 Aug-18 Aug-18 0% 0% 50% 50% 250% 200% 150% 100% 250% 200% 150% 100% rainfall average Below Jul-19 Jul-19 Jun-19 Jun-19 May-19 May-19 Apr-19 Apr-19 Mar-19 Mar-19 Feb-19 Feb-19 Jan-19 Jan-19 Dec-18 Dec-18 1-Month Period for Don 1-Month PeriodAire for Nov-18 Nov-18 Oct-18 Oct-18 Sep-18 Sep-18 bove average rainfall bove A Aug-18 Aug-18 0% 0% 50% 50% 250% 200% 150% 100% 250% 200% 150% 100% Soil Moisture Deficit Soil Moisture Deficit River Flow Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data Addingham, WHARFE Birstwith, NIDD Ranking derived from data for the period Dec-1973 to Dec-2017 Ranking derived from data for the period Dec-1976 to Dec-2017 20 45 18 40 16 35 14 30 12 25 10 20 8 15 Flow (cumecs) Flow (cumecs) Flow 6 10 4 5 2 0 0 Oct-18 Dec-18 Feb-19 Apr-19 Jun-19 Aug-19 Oct-18 Dec-18 Feb-19 Apr-19 Jun-19 Aug-19 © Environment Agency 2019 Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data Briggswath, ESK Buttercrambe, DERWENT Ranking derived from data for the period Jan-1993 to Dec-2017 Ranking derived from data for the period Sep-1973 to Dec-2017 20 50 40