Study identifies risks to drinking water from UKOG’s South Downs oil drilling plan


The Markwells Wood oil site

New questions have been raised about whether drilling for oil should be allowed in an area of the South Downs that feeds a source of drinking water.

UK Oil and Gas Investments plc (UKOG) has applied for permission to drill new wells and produce oil at Markwells Wood. The site is in the catchment of the Bedhampton & Havant Springs, which provide water to the Portsmouth area.

An independent study for a local community group has concluded that water contaminated by oil exploration or production at Markwells Wood could quickly reach the springs 8km away.

It also argues that the area had been incorrectly classified for groundwater protection and should have greater safeguards that would prohibit drilling for oil.

Markwells Wood Watch, which commissioned the study, has urged the South Downs National Park Authority to refuse planning permission.

In November last year, both the Environment Agency and Portsmouth Water objected to UKOG’s planning application for Markwell’s Wood. They said the company’s groundwater risk assessment was inadequate. The two organisations are expected to comment next week on a revised risk assessment.

Speed of water

The threat to drinking water depends partly on the speed with which any contaminated water could travel underground through the chalk to the Bedhampton & Havant Springs.

Aidan Foley, the author of The Markwells Wood Watch study, estimated that groundwater in the chalk aquifer at Markwells Wood could reach the springs in around 10 days. This is far faster than the Environment Agency (EA) has estimated.

The EA has said it would oppose hydrocarbon development in areas where underground water below a drill site could reach a drinking water source in no more than 50 days. These areas are classified as a Source Protection Zone 1 or SPZ1.

Markwells Wood is classified as a Source Protection Zone 2 (SPZ2), an area within 51-400 days travel time to a water source.

But Dr Foley said:

“There is considerable justification for the designation of the area around the UKOG site as within SPZ1.”

Markwells Wood Watch SPZ1 campaign

Markwells Wood Watch SPZ1 campaign. Photo: Markwells Wood Watch

Fissures in the chalk

One way groundwater and pollutants can travel rapidly through chalk is along what are known as karstic features. This is where chalk is dissolved to create fissures and conduits, along which water and contaminants can flow.

Last year, the Environment Agency said if there was strong evidence to suggest karstic flows in the area of the UKOG site it would treat it as if it was in an SPZ1 and oppose oil and gas operations.


UKOG’s revised risk assessment concluded that the chalk near Markwells Wood had “less potential for solution weathering and karstic flows” than other areas in the South Downs.

But Dr Foley concluded that sink holes and dry valleys around UKOG’s proposed site and along the route for vehicles visiting the site were evidence of underground fissures in the chalk.

Dr Foley said:

“All of the geological and groundwater conditions required for karstification of the Chalk Principal Aquifer are in place at Markwells Wood.

“There is an almost complete absence of surface water within the district, with the exception of ‘Winterbournes’ flowing in normally dry valleys during periods of unusually high groundwater recharge, thus indicating that all flow is concentrated in the subsurface”.

Dr Foley said:

“Due to the high groundwater velocities (up to several kilometres per day) that frequently occur within flowing fractures, fissures and conduits, karstic groundwater supplies are among those most vulnerable to pollution.”

He said tracer tests from nearby Rowlands Castle proved that groundwater was travelling more than 12km a day and reaching the springs at Havant in about nine hours.

He said:

“The weight of these observations, on the basis of multiple lines of evidence, suggest that karstic groundwater flow conditions, of potentially kilometres per hour, are present in the vicinity of the UKOG site at Markwells Wood.

“There is little evidence to suggest that what takes 9 hours to travel from Rowlands Castle to Havant (a distance of 4.6 km), would take over 50 days to travel from the UKOG site to Rowlands Castle (a distance of less than 3.5 km).”

He said the delineation of the SPZ1 and SPZ2 zones appeared to be based on what he called “incomplete mapping of surface karst features”. He also questioned the basis of the calculations of the transport of contaminants.



Jo Hawes, who lives in Forestside, the nearest village to the Markwells Wood, said:

“The risk of water pollution as a result of drilling for oil is obvious. I believe the local authorities must take a precautionary stance and not allow an oil company to chase short term profits at the expense of our long term health.”

Reed Paget, a member of Markwells Wood Watch, said:

“It is now clear that the groundwater in this region is moving very quickly and if there is an oil spill, the people of Portsmouth could have chemicals in their drinking water in a matter of days. This is far too great a risk to accept. I hope Portsmouth Water and the EA do what’s right for the local population and object to UKOG’s oil extraction proposal next week”.

UKOG response

UKOG gave the following response:

“The report commissioned by MW Watch has been written in response to the old groundwater risk assessment submitted with our planning application in September 2016. However, subsequent to this and following discussions with the Environment Agency and Portsmouth Water, we have carried out a more comprehensive and detailed assessment. This was delivered to the South Downs National Park Authority in early March of this year and is currently being reviewed by both the Environment Agency and Portsmouth Water as part of the statutory planning application consultation process.

“Our assessment, like the report commissioned by MW Watch, recognises the high sensitivity of the chalk aquifer and shows that robust mitigation measures are required to manage the risks associated with our development. Since the wellsite has already been constructed in accordance with modern industry standards, the only potential risk associated with our development relates to the construction of new oil wells through the chalk aquifer.

“This low risk will be managed by constructing new wells using the same techniques used in the water well drilling industry. This will include using a British manufactured, natural, biodegradable drilling fluid in our operations. This zero-hazard water-based drilling fluid is the only drilling fluid to be formally approved by the Department for the Environment, Food and Rural Affairs for use in drilling wells for public water supply and will help to ensure that there is no impact to the Havant & Bedhampton Springs during the drilling process.”

The South Downs National Park Authority is expected to consider the UKOG application on 11 May 2017.


UKOG submits new information on South Downs oil drilling

DrillOrDrop page on Markwells Wood

Planning application documents

Dr Foley’s report for Markwells Wood Watch

Updated 4 April 2017 to include response from UK Oil & Gas

40 replies »

      • PhilC. The fact is the fracking water contamination case in Dimock Pennsylvania was used as the prime example and foundation for the environmentalist and anti fracking brigades to make their points and claims as scientific. Well now the Fefderal court found that the plaintiff story and scientific evidence are flaw and inconsistent. And it overturn the original verdict. So whether it is reported by this journal or the anti fracking favorite RT and Guardian is irrelevant. It is the fact that counts. And I am sure the Guardian and RT or alike wont report such news because it would defeat its own political agendas.

        • American thinking? Ha ha! Almost as funny and sad as the American slot machine legal system!
          I wonder how many millions of dollars were shovelled into the legal eagle slot machine until the desperate o&g pr machine got the cherries they wanted up on the tumblers ?
          It will be the same here, I will stick with the original adjudication in this respect thankyou. Desperate legal teams throwing o&g money at the truth does not convince or impress. Just another aspect of the panic to prevent the mud from sticking and it doesn’t wash off.
          I can see the UK and American legal eagle ambulance chasing lawyers sniffing around the o&g industry around waiting for the next layer of mud to stick, it wont be long…..

  1. Democracy not acceptable to you refracktion? You certainly won’t get a free ride in Blackpool, can’t see why you should expect it here.This is supposed to be a site that is independent-and that means views and statements on both sides will be challenged. FOE should have expected that. (They did-which is why it was FOE Ltd. that were used.) Shouldn’t say too much about multiple identities, you may unearth a whole can of worms.
    How are you getting on with the ASA refracktion, ref. Ineos?

    • I’m a big fan of democracy Martin – I’m just not such a big fan of people whining about a page on which they are commenting, specially one where the moderators allow you to get away with insulting them because they are basically very fair. Nobody expects a one sided discussion, just that you and your “new” friend should observe a few social niceties whilst you are attempting to make your points (such as they are)

      The ASA with Ineos is progressing fine – nice of you to ask.

  2. Are the journalists running this on holiday? There have been a few stories go unreported.
    Ineos just bought a lot of extra clout.

  3. Sorry refracktion, of course you are never “moderated” so your social niceties are a level above others?

    I quite accept being edited on this site. Sometimes I have a sympathy with the reasons, sometimes I don’t, but that’s life. But, that is someone else who has that responsibility, not you.

    Whichever side of the debate we are on then there are numerous cases of misinformation, rants or poor science. If you removed all of that this site would be largely empty! (Nice “fear” story about sink holes-then why not take a look at Southampton Geothermal Heating Co. Ltd. sited between Ikea and West Quay Shopping Centre. Bit closer than China. But that is classed as “alternative” energy, so not a “problem”?)

    Enjoy the Guardian’s insight into the world of business- before it goes bust! (I’m sure no one will appreciate the Unite motivation reference Ineos.)

  4. “Sorry refracktion, of course you are never “moderated” ” – LOL you do post some codswallop on this site but that is one of your finest. I do get moderated but it’s normally for things I say about rabid pro-frackers rather than our hosts here.

  5. There are three possible routes for contamination of groundwater:
    surface run-off from the drill site
    drilling fluids during drilling
    hydrocarbons during production
    These possibilities are managed in every well plan.

    Surface run off is easy to control with the use of a concrete pad and rubber matting. The photo appears to show that the site is flooded, so the impermeable barrier is working. (This issue is no different to how it is dealt with at any petrol station)
    The report suggests that there could be karsts/fractures down to 200m. If there are any losses during drilling, or if these are known about from other wells, it is easy to drill with air, foam, or a suitable mud to stop losses. Once the well has gone through the loss zone, the hole is cased and cemented, and drilling continues with mud.
    On completion, after casing, cementing, and running the completion string, there are multiple barriers between the hydrocarbons and the aquifer zone. (Standard oil field practice).

    • I beg your pardon? “Surface run off is easy to control with the use of a concrete pad and rubber matting”? Clearly you are not an engineer, i am, you do not and cannot control surface water run off by the use of concrete pads and rubber matting!! Surface water run off from an oil and petrol usage site requires an approved and monitored method of separation and disposal or transport off the site.

      There are a number of possible ways to do this, and they must be implemented at the start of activities on site and permissions acquired pre start.

      1. Surface water collection via an oil and petrol interceptor and the excess separated and taken to a surface water drain in the road, there seems to be no provision available for that on most if not all sites due to their isolated rural locations.

      2. Surface water collected via an oil and petrol interceptor and the excess separated and taken to a surface water soakaway, however this is rarely possible on agricultural land and there are laws to control and prevent that in the case of oil and petrol separation interceptors. If the surface water is just allowed to run off onto the surrounding soil carrying with it the spills and the accidents, then that will contaminate the agricultural land and water courses adjoining the site. Surface water run off can travel miles on a clay sub strata before emptying into a water course.

      3. Collection and transport off site, via a pump sump (or several) and tankers to a registered disposal site where the effluent can be dealt with safely, considering its potentially explosive nature.

      4. Ignore all that and just let the contaminated run off pour onto the surrounding land, water courses and crops.

      5. The oil and petrol separator must be cleaned and regularly serviced to ensure it is working properly, badly installed separators and interceptors are worse than useless. That will be a large perforation of the membrane and that should have been installed and sealed off prior to work starting, that is why one cannot simply start on an existing site without these items being installed and checked.

      A single impermeable membrane will rarely survive the vehicular movements of slewing and tearing that HGV’s produce and there will be tears and holes caused by sharp edges from site use or natural materials below. A surface protection layer is essential in this regard, i would have ensured there were two impermeable membranes, one above and one below the hardcore base layer and any perforations sealed and secured and also a monitoring sump and running surface layer suitable for HGV tearing movements installed on or just below the surface.

      I have extensive personal experience of decommissioning oil and petrol distribution networks here and the middle east and i have seen the most horrendous pollution caused by just such a lessez faire attitude towards run surface water off from active drilling to distribution and collection sites, pumping stations, standing areas and transport depots.

      You have missed one by the way, that is foul drainage, that, if not connected to mains drainage will also require storage and transport off site, a well designed and installed bio digester will be required (another perforation of the membrane), the old style septic tanks rarely work properly in a working site location since strict useage of bio digestible products are rarely adhered to and that destroys the digesters ability to turn the waste into sludge. Incidentally that will also require a run off to a drainage system fo clean(ish) water somewhere.

      These are all above ground considerations and should have been tightly controlled in the planning permission and building regulations procedures. If they were not then someone has dropped a large one and there will be one god almighty stink.

      • Thanks for elaborating on my general comment regarding surface run-off. I agree 100% with you regarding monitoring of separation and disposal, implementation, and permission. This wil ensure a fully safe and compliant operation.

      • Phil C – I agree with everything you have noted (don’t fall off your chair), this is what the Industry does, and no doubt any other industry. It is rightly a plannng requirement and no permissions are granted without adequate catchment, separation and disposal. And it is policed. Even back in the 1980’s when I worked onshore UK. I expect there will be many keeping an eye on local water courses etc. ready to report the first sheen seen onthe water.

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