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Case Study - Borehole Cross Connections 2015

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Case Study - Borehole Cross Connections 2015

  1. 1. CASE STUDY: BOREHOLE INSPECTION PROGRAM – CROSS CONNECTIONS HERE WE HAVE 4 EXAMPLES OF THE PROCESS OF HOW I DECIDE IF A FARM IS WORTH INSPECTING IN ORDER TO LOCATE A CROSS CONNECTION. BGS = BritishGeological Society EA = EnvironmentAgency QuickLinkcross connection – as youcan see onthe leftisthe Borehole connectionandonthe rightisthe mainsconnection.The quicklinkcanjustbe seenonthe right handside.This farmerwasissuedwithasection75 and the workto be done isas follows; Cut back andcap mains pipe to before the tap Or hardpipe mainsintoheader tank with correct AA or AB air gap. METHOD Afterseeingthatthe consumptionhadreducedonthe meterbyoverhalf andthat thisfarm apparentlyhasa Borehole according toBGS & the EA,I decidedthatI had to urgentlyvisitthe site. The chance that the farm hada backupfor itsborehole was toohigh so I made ita toppriorityto visitthissite.
  2. 2. DirectCross connection –Black pipe cominginfromthe top ismainswater,the horizontal pipe isthe Borehole.The preventiononthissetupisjustnotfitfor purpose.There isa pumpon the systemwhichcouldleadtomasscontamination givena mainspressure dropinthe area anda failure of the valves.Worktobe done; Remove physical linkin the first instance,hard pipemainsinto header tank in farm buildingwithappropriateAAor AB air gap Or cut and cap mainsand providebackup power source for Borehole pumps. METHOD Thispropertysupposedlyhada Borehole andInoticedthatit alsohad mains(thisis the basicsof finding properties which are likely to havea crossconnection) Ialsonoticedthat fora farmwithcattle it seemedthatthe consumption was notaddingup,thisbill showsonlydomestic use whichimmediatelygivesanindicationthatthe mainsonsite couldalsobe leadingtoa connectionincase of emergency. PLEASE SEE BELOW LARGE PICTURE OF A DIRECT CROSS CONNECTION TO A PIGGERY
  4. 4. Directcross connection – the mainswatercomesinfrom the rightas shownon the diagramabove,the connectionis straightintothe filteredBorehole waterwhichcomesfromanotherpartof the farmand the none filteredBorehole waterwhichcomesdirectfromsource.There isone pipe whichfeedsdomesticandanotherwhichfeedsapiggery. Thisis one of the bestexamplesIhave foundof a cross connectionasitcame withinstructionsanddiagramsof how the setupworked.The diagrams(andmyown) show that there isa loopundergroundwhichconnectsthe pipes together.The onlycontrolsonthe system are the tapsyou can see.The same farmerhas 5 otherpropertiesall with the same setup,he isaware that the connectionshouldnotbe inplace andis now on the righttracks of fixingthe problem.Workto be done; Remove physical linkin the first instance,hard pipemainsinto header tank infarm buildingwithappropriateAA or AB airgap Or cut andcap mainsand providebackuppower source for Borehole pumps. Do thisfor all sites and provideproof ofworks being carried out. METHOD I saw thatthis propertyhada negative readingof 8m3/hon one of the monthswhichcouldbe one of two things,a meterfaultor the use of a cross connection.Itookitto be the latterand decidedtohave a lookformyself.The propertyhadto have anothersupplyof wateras it isa pig unitand agricultural site soneedswaterforatleastsome of itsprocesses.There ishardlyanywaterbeingusedthroughthe meteratall exceptata guess,onlywhenthe Borehole hasfailed.
  5. 5. QuickLinkcross connection – Thiscustomerhad onlyeverusedthe quick linkonce in30 years.He has itsealedeitherendandthe quicklinkhasto be bracketedon.I issuedasection75 and made the customeraware of the riskto himself andothersinthe areaif he were toconnect this up. Withhimnot beingable tolocate the stop tap I decidedtouse myown judgementand clearlystatedthatif he were touse the cross connection he wouldbe prosecuted.Worktobe done; No physical workto be carried out,customer is aware that if he were to use this crossconnectionhe wouldface prosecution.Accountwill be checked to see if usagespikes (otherthan a burst) METHOD From our billingsystemInoticedaspike inthe usage inApril 2014, I alsosaw that there were afew recordsof high usage out of the normal.Due tothis site alsoapparentlyhavingaBorehole Idecidedtotake a lookat the site and see whatI couldfind.Iwas once again expectingtofindsome formof backup forthe Borehole wateronsite.The Farm ismainlydairycattle so the usage inwaterwouldhugelyincrease if onmains. THE FOLLOWING IS AN EXAMPLE OF A GOOD INSTALL AND WHAT WE WANT TO SEE ON BOREHOLE SITES
  6. 6. Thisinstallationwaswhatwe wanttosee when we get to a site,especiallyone whichhadalarm bellsringingwithitsmeterreadings (asseenat the bottomof the page). Unfortunatelythis installationisstill notentirelytothe regulations as it hasan AFair gap whichisan obstructionto the overflow.The customerisaware of this. The tank has mains waterintothe top and borehole waterintothe bottom,the pipe with the white label onitisthe overflowfromthe tank. The farmerexplainedthe massivechange inreadingsas beingaleakwhichhad to be isolatedbyturningoff the mainstoptap. Thiswas a recentinstall ona poultry farm,we wantto findthissort of install onall newsites. Hopefullywiththe correctAA,ABairgapinplace METHOD The readingon the AMR metermade me thinkthat the farm had simplyreduceditsmainsconsumptionand switchedovertoitsborehole in2014, Takingthe historyintoconsiderationIdecidedtotake a lookformyself.We knewthe site hada borehole thankstothe BGS & EA records. Robert Mulderrig- Yorkshire Water- Water Regulations– 07790616382 - Robert.mulderrig@yorkshirewater.co.uk