Flood Watch

As we moved into 2021 January storm Christoph saw more periods of heavy rainfall and more local flooding up to the very last day of the month, by which time the monthly average rainfall was exceeded by 75%. February started milder but by the end of the first week temperatures plummeted to -5 centigrade over night with daytime temperatures around zero and we experienced the first snowfall brought about by the “Beast from the East 2”, named Darcy. This was followed by a week of strong winds with coastal speeds of over 80 mph although locally they only reached 45 mph. In spite of these wind speeds and the issuing of yellow warnings the storm remained unnamed (should have been Evert!).The instability of the jet stream which had brought down cold polar air suddenly reversed to bring warm air from the south. The monthly rainfall returned to average and although the river level peaked several times no more flooding occurred.

March started slightly warmer but wind chill factor kept temperature in single figures. However rainfall throughout the month has dropped and should end up below average. As we approach the end of the month the Spring equinox will be reached by the 20th when day and night hours are equal at the equator although locally this will occur on 17/18th being in the northern hemisphere. On the 27th the clocks will go forward 1 hour when sunset will be at 7.30pm and daylight hours would have extend to 12 hours 40 minutes.

April’s forecast expects a period of more stable weather as long as US hurricane season does not create problems with the jet stream. An historic event on 28th February saw a meteor stream deposit debris of up to 300 grams in Gloucestershire. The finding of such fragments, not seen in over 30 years, identified the age in excess of the earth at 4.5 billion years. I have been informed that our local E/A contact has been re-assigned to a new location and that all contact will revert to the Partnership and Strategic Overview team. I have contacted the team leader to try to ensure continuity and that he is fully aware of our concerns over lack of progress. I am currently awaiting his response to my E-Mail.

J.Arnold

Flood Watch

2020 will go down in history not only for Covid but for the extremes of weather that set new records for wettest February, sunniest Spring, heat wave in late July/August. Excessive rainfall in October and December resulted in the annual rainfall total exceeding average levels by 20%. Especially noteworthy was the 35mm that fell on 23rd December resulting in flooding levels not seen since March 2016 when the E-W culvert caused flooding in the middle of the Village. River level rose by 2m resulting in extensive flooding along the Nene. Notable was the evacuation of the Billing Aquadrome caravan site down stream of Northampton. The good news was that the alterations to the E-W culvert outflow prevented a repeat of the devastating event of 2016.

As the year ended the UK was battered by storm Bella followed by a period of excessively cold weather when temperatures barely rose above freezing. This continued into the start of 2021, interrupted by brief periods when temperature rose to more typical winter levels of around 5 to 8 degrees.

As we move further into 2021 the next major storm Christoph (to be followed by Darcy) could cause more flooding whilst the immediate future appears to remain unsettled with longer term forecasts being even more uncertain. However the only certainty is that daylight hours will continue to increase by 3 hours with the end of winter and the spring equinox and the change from GMT to BST on 28th March. As a result lighter evenings will return.

The flooding on 24th December prompted some research into the archives for the River Nene locally dating back to 1945. As increased flow rates are a sure indication of flooding events a rate of 5 cum/sec resulted in 160 events while 10 cum/sec occurred 11 times. These correlated with my own records of flooding over 23 years with the events of March 2016 and December 24th 2020 corresponding to a 10 cum/sec event. Also apparent was the increase of 10 cum/sec events since 2000, a clear consequence of climate change!

A major event in 2001 year event, namely the Saturn/Jupiter alignment in Aquarius on 21st December was a non-event due to cloud cover.

The E/A has still failed to make any progress in securing funding for completion of flood defences in the Village. As a reminder of the continuing risks I have forwarded copies of photographs of the flooding on 24th December and reminded them of the potential impact of climate change to stress the need for action now!

J.Arnold

Flood Watch

Wet, wet, wet describes October’s weather with storm Alex at the beginning of the month and storm Aiden in the closing days of October into the start of November. Although October is normally the wettest month in a year this year has been exceptional with nearly double the normal average,even exceeding the February high. Strong winds from Atlantic lows resulted in unsettled weather patterns with local wind speeds of 30 mph whilst areas of the UK experienced 70 mph,heavy rainfall and flooding. The remainder of November will see daytime temperatures around 10 degrees centigrade with a small risk of overnight frost. With daylight hours continuing to fall, currently at 8 ¾ hours,changing at 2 minutes per day this will continue until 21st December, the official start of winter when daylight hours will start to increase. As winter is characterised by periods of stormy weather the next UK named storms will be Bella, then Christoph, alternating names being male then female.

The anticipated blue moon at Halloween was obscured by night clouds although the moon rise in the east formed an impressive sight as the Nene Valley was flooded with bright moonlight, circa 5.30 pm.

With saturated ground conditions the river levels respond rapidly to new rainfall and more rapid run-off. This is a reminder to assess your own potential flood risk both from the river, brook or flash flooding and poor surface water drainage. In my own case the Easter 98 floods initiated an assessment of my own property risk resulting in a three tier system of protection. Tier 1 resulted in the creation of a relatively water tight enclosure across the full width of the property by removing gateways in a low level wall to create a single entry/exit point which is permanently protected by a flood barrier permanently fitted. This comprised a timber structure with glued joints using copper pipe lagging to form a compressible seal. In the event of leakage a submersible pump can be employed to remove unwanted water. As the garden has tiered levels a second wall can be similarly protected should the need arise. In the unlikely event that flood water reached the house the vulnerable entry points above dpc level, such as door openings or patio doors can be similarly protected. In the latter case the flood guards can use polythene sheet applied across the opening before installing the guard. A guard was produced for each opening and the wall predrilled and plugged in readiness for a rapid response should the need ever arise. To protect brickwork and provide a waterproof seal the area of walling 18 inches above ground level was treated with a clear silicon sealant.

Since 1998 only tier 1 and the use of the pump on one occasion has needed to be employed, maintaining leakage levels below 1 inch! These precautions may seem excessive but with increasing risk from climate change I feel well prepared.

J.Arnold

Flood Watch

Post Autumn Equinox saw major changes in the weather with the final days of September seeing temperatures falling well below a normal monthly average and an increase in rainfall. Overall September had a two week period with no rain but with the above changes resulted in a final monthly rainfall of 35% of normal. However October brought major changes with storm Alex (European name) and heavy rainfall on the 3rd, the wettest October daily level since 1891, well over 30mm. As a result, when combined with additional rainfall on the following days the River rose by 1.6m and areas of the floodplain were submerged on the 5th. Within 24 hours all flood water had receded. Overall October has been a very wet month and with further rain forecast for the remaining days the monthly total is expected to end up about 150% of average.

The month has been full of planetary and lunar activity with Mars appearing at its largest on 6th when the planet was closest to the Earth and later on the 13th when the planet was at its brightest, an event repeated every 15 years. Unfortunately on both occasions overcast skies at sunset blocked any visible sightings. Fortunately the night‘s sky between the hours of 2 am and 5 am cleared and Mars was clearly visible as it traversed from the SE to SW. October also had two full moons, a Harvest Moon on 1st and a Hunter blue Moon on 31st, Halloween.

An E-Mail was received from the E/A in which it was clear that little progress had been made over the last year. However, following my comments regarding the criteria for Grant-Aid funding to protect properties, currently based on properties actually being flooded and their role to prevent flooding, a revised set of criteria has been defined by Defra in February 2020. This will now be taken into account during the economical assessment and relates to the impact of flooding on the individual’s well-being. In particular the areas of concern are namely:-

● lack of warning
● whether flooding events were in day time or night time
● duration of flooding
● extent of flooding
● speed and depth of flood water
● repeat of flood events
● potential cost impacts
● what the impact of climate change will be on future flooding

Although research on the impact on the individual or household is limited it is now at least recognised that these have a profound impact on PTSD symptoms and that a high score rating should be applied. Throughout the document comments were made relating to the serious limitations of flood risk maps and their use in predicting the extent of such events. At least these criteria can now be applied to any revised assessments for village flood defences.

J.Arnold

Flood Watch

A reminder of the on-line access to real time data for rainfall and river levels and flood map risk planning websites relevant to Nether Heyford.

Latest recorded levels of the river Nene can be found on the Shoothill GaugeMap website.

Upstream at Flore:

Link: https://www.gaugemap.co.uk/?fbclid=IwAR2DdUovxyz69PkLN7mCTLdQ3ZcsJtAtooMzN-y2MP6wb53J2aXp9O99mU0#!Map/Summary/11644/7051

Downstream at Bugbrooke:

(B) River and sea levels  Flood information service for England from Gov.uk

(C) Northamptonshire County Council: www.floodtoolkit.com

GOV.UK Check your long term flood risk | GOV.UK Flood map for Planning | Nether Heyford: Flood map for planning

Re-Published from earlier Flood Watch articles in 2020 from J.Arnold

Flood Watch

August ended with very unsettled weather notably due to storms Ellen and Francis, the latter reaching 80 mph in coastal areas. Locally wind speeds of 45 mph were recorded with the accompanying rainfall raising August’s total to 150% of average. These storms were the last of the 2019/2020 named storms with 1st September starting afresh with the next named storm to be Aiden. The 3rd of September was notable with a full moon called “the Corn Moon” being readily visible in the clear night sky. Throughout September the weather has been variable with periods of average temperature inter spaced with near record temperatures approaching 30 degrees due to the jet stream drawing warm southerly weather from Europe. Notable was the lack of rainfall, well below average at about 25% of average. The forecast for the remainder of September will see a return to more seasonable weather with reducing temperatures but with a low risk of rain.

The 23rd of September will be marked equatorially with the Autumn Equinox with Northamptonshire achieving equal day/night hours of 12 hours on 25th. In the following days daylight hours will reduce by 4 minutes per day.

Contact has been made with the Environment Agency to question why no active plan for further flood defence/repair/maintenance has been prepared since the completion of the Horestone Brook conversion in late 2017. Since the merger of Lincolnshire with the Anglian Region it seems priority is being given to the more flood prone area over Northampton.

J.Arnold

Flood Watch

The summer solstice on the 20th June marked the change from spring to summer with the longest number of daylight hours,namely 16.75. The month ended with average rainfall and three days when the temperature rose above 30 degrees centigrade. A notable event in the early hours of the 26th was a totally red sky often associated with the saying “a red sky in the morning-shepherd’s warning” indicating the replacement of high pressure with more uncertain weather to follow. July returned to more typical temperatures until the last day when a record 36.1 degrees was recorded. Thundery conditions across the UK gave rise to a local tornado on the Saturday 25th which started in Weedon and tracked across Flore, Nobottle, Harlestone Heath and Moulton, lasting 15 minutes in total. The local ITV News recorded the devastation to allotments in Moulton. Again the month ended
recording average rainfall.

The beginning of August was marked by an African heat-wave when temperatures again rose to over 30 degrees for three consecutive days accompanied with night time temperatures over 20 degrees known as “tropical nights”. Inevitably these extreme conditions gave rise to thunderstorms which caused surface water flooding nationally. Locally our first rainfall of the month fell on the 13th with a 15 minute deluge. The longer term weather forecast for the remainder of the month looks to be unsettled with cooler, showery weather. As a result another month will end up with average rainfall resulting in the years total so far being average (brought about by extremely wet February and dry May).

23rd September will mark the autumnal equinox or start of autumn when day and night will be of equal length.

On the 3rd July a willow tree which was causing a complete obstruction to the free flow of river water was finally removed by E/A contractors.

For those interested in cosmic events a comet was forecast to be visible on 23rd July and extended meteor showers from mid July to the end of August. Given a clear sky these are best seen around 5 am just before sunrise.

In spite of all the problems caused by the introduction of Permitted Developments whereby properties could be extended without planning application which resulted in breaches of compliance with planning regulations and the continued building on floodplains, the Government has recently announced its intention to allow conversion of shops and offices to homes without formal planning application. It looks as though this marks the end of enforcement of strict building regulation and standards.

J.Arnold

Flood Watch

Chaos theory, a phenomenon well known to physicists and climatologists, coupled to climate change could be the reason for meteorologists being astounded by unprecedented changes to the UK weather pattern in 2020. Those of us that grew up in the 1960’s and 70’s experienced regular seasonal patterns, snow and ice in winter, wet springs and long hot summers. However since the late 70’s global temperatures have been steadily rising with changes in the southern hemisphere triggering changes to the global weather patterns. Locally 2020 has seen new records set for the wettest February (over twice monthly average) following a mild winter, the warmest spring and the driest May (only 12% of monthly average). No rain was recorded from 3rd May to 4th June. Since then June has continued with endless showers although only two days the 7th and 18th recorded over 10mm. The remainder of June is expected to see warmer weather returning with the years total rainfall so far expected to be below the usual average to the end of June.

Having recently been contacted by a potential house purchaser enquiring about flooding risks in Nether Heyford reminded me of the role of a flood warden, his deputy and any other wardens located within the Village, all of whom should be registered and insured by the Environment Agency. They are expected to raise awareness of flood risks, help pass on flood warnings and help prepare for flooding events throughout the Village. Acquired local knowledge will often identify potential events before the E/A flood warning service. During flooding events they would coordinate all emergency services, bearing in mind that all agencies will be attending higher priority events elsewhere. An important activity is regular inspection of ditches,culverts, brooks and river and recording the extent of all potential flooding events. A Community Flood Plan should be prepared identifying all areas at risk, each given a rating and action to be taken. A full listing of all contact numbers for wardens and emergency services should be included. It would be helpful to have such a document posted on the Village web site and a reference included in the Welcome pack.

J.Arnold

Flood Watch

The 7th of May witnessed the third super moon of the year known as the full flower moon. Such super moons occur when the earth and moon’s elliptical orbit brings the earth and moon to their closest proximity or perigee and the moon appears approximately 15% larger in diameter. The event on the 7th of May was accentuated by clear night sky and resulted in an extremely bright yellow/golden glow on the moon’s surface.

The month of May continued with extremely low rainfall with only 12% of the average monthly rainfall recorded up to 20th. Day time temperatures have fluctuated from 8 to 24 degrees centigrade with a record of 27 degrees forecast for the 20th. This will be followed by some thundery weather with possible light rain with the end of the month returning to a more settled warmer spell.

In the May issue of the Prattler I mentioned assessing your own risk from flooding. Within the Village there are two possible causes, by river or brook or by flash flooding resulting from heavy rainfall. Flash flooding and local drainage is the responsibility of the LLFA whilst the E/A are responsible for the river and brook.

The following web sites provide a useful starting point:-

(a) GOV.UK Check your long term flood risk

(b) GOV.UK Flood map for Planning

Nether Heyford: Flood map for planning

In (a) three categories are identified by zone 1, 2 or 3, zone 1 being lowest risk of 1 in 1000 years(0.1%) and zone 3 being 1 in 100 years(1%) or less. Zone 3 can be subdivided into 3a or 3b the latter being the natural floodplain of the river. In (b) the risks are categorised into low, medium and high. The NPPF rules require climate change to be taken into account especially when making planning applications. This requires an increase in river flow rates of up to 65% when predicting the increased impact of buildings estimated over 100 years.

None of the published risk maps include the impact of climate change.

As with any predictions of flood risk from modelling the results are subject to the accuracy of input data especially rainfall in catchment area and ground terrain profile accuracy. Even the choice of elements within the model and the selected grid size can radically change the output. The best cross check is to correlate to actual recorded events.

The most reliable sources of information lies within the local community especially with those that reside close to the potential sources of risk and who have first hand experience over several decades. So in assessing your risk familiarise yourself with the maps and then ask questions of local residents.

J.Arnold

Whilst our local flooding risk is comparatively low we must remain vigilant. Besides local and National weather news forecasts a reminder of the on-line access to real time data for rainfall and river levels is listed below:-

(A) Shoothill GaugeMap:  www.gaugemap.co.uk

Upstream at Flore:

Downstream at Bugbrooke:

(B) River and sea levels  Flood information service for England from Gov.uk

(C) Northamptonshire County Council: www.floodtoolkit.com

Finally don’t forget to register with the Environment Agency  flood warning service on Floodline 03459 881188 to receive telephone and advanced flood warnings for the area.

J.Arnold