The paper documents the experiences of a project funded
by the Government of Norway (NORAD Programme) and
managed by the South African Department of Water Affairs
and Forestry (DWAF)

Phillip Ravenscroft (7218407)

English

Loughborough University Institutional Repository

RAVENSCROFT21928th WEDC Conference Kolkata (Calcutta), India, 2002Managing rural groundwater suppliesPhillip Ravenscroft, South AfricaSUSTAINABLE ENVIRONMENTAL SANITATION AND WATER SERVICESTHE SOUTH AFRICAN government has a policy for ruralwater supply that effectively translates into supplying allrural communities with piped water. Being a relatively aridcountry, the implication of this is that many communitywater supplies are dependent on ground water and moreand more ground water schemes are being developed.The paper documents the experiences of a project fundedby the Government of Norway (NORAD Programme) andmanaged by the South African Department of Water Af-fairs and Forestry (DWAF). The aim of the project is toprovide DWAF wi1th guidelines on establishing agroundwater management system for community watersupplies. The project forms part of a programme that hasthe overall objective of improving the sustainability of ruralgroundwater supplies.The project has involved piloting the establishment ofgroundwater monitoring systems in two separate areaswith a total of 35 boreholes being monitored. Some of theschemes are being operated by community based watercommittees and others are operated directly by local gov-ernment.Within the overall objective of improving sustainability,the motivation for monitoring ground water is a combina-tion of operational and resource management considera-tions. From an operational perspective, it gives an earlywarning system for when equipment is not functioningcorrectly and allows action to be taken before the systemfails. By monitoring the performance of the aquifer, one canpreempt failure of the system from over abstraction and bein a position to know which ground water resources areunder utilized and have the potential for further develop-ment.The nature of South African geology is such that mostboreholes for community water supplies are drilled intohard rock aquifers and are relatively deep (40 to 120m).Most recommended long-term pumping rates are based onone or two day pumping tests. These tests give an indicationof the potential yield but due to the nature of fractured hardrock aquifers, it is only possible to establish the actualsustainable yield by monitoring water levels and abstrac-tion over much longer time periods.Monitoring pre-requisitesThe following pre-requisites are needed for groundwatermonitoring:• Equipment – the boreholes needed to be equipped withthe facilities for monitoring and the operators neededtools to measure and record information.o Water meter for measuring abstractiono A tap at the source for water quality samplingo Piezometer tube for water level monitoringo A dip meter and a logbook for taking and recordingdata• Training for pump operators to take and record data.• Flow of data from the pump operators to the localauthority.Water quality monitoringLocal government is legally required to have a water qualitysampling plan in place. Rather than duplicate this with aseparate groundwater sampling plan, the project is work-ing with local government authorities to design and imple-ment their water sampling plans. Because water qualityrelates primarily to the health of consumers, the samplingplans are focused on the tap or point of supply as theprimary sampling point. When water samples from the tapindicate contamination, more samples are taken at variouspoints including the borehole, to trace the source of con-tamination.Flow of InformationFigure 1 shows the relationship between the various insti-tutions and the flow of information between them. Thefocal point of the project is the local government institutionand they are the target for building capacity and developingtools for ground water management.• Data is supplied by the pump operator on a bimonthlybasis to the local authority who enters the data in aspreadsheet based software package. The logbookshave a carbon copy so that a complete record of the dataremains with the pump operator.• Summary data is provided to the catchment manage-ment agency.• The legal bindings (abstraction permits and water serv-ice provision contracts) are contained in water relatedacts of South Africa.RAVENSCROFT220Aquimon groundwater managementsoftwareAquimon is a GIS based viewer for graphically displayingthe borehole time-series data. The data is stored in an excelspreadsheet and the software is a user interface withinwhich one can select a particular borehole. One can thenview a series of graphs for the selected borehole and view(and edit) basic borehole information, monitoring recom-mendations and water chemistry information.               LEGEND Legally Binding Relationship Flow of data, information INSTITUTION PUMP OPERATORS  Community based employee or employed by Local Government or agency of Local Government LOCAL GOVERNMENT Legally responsibility for ensuring water supply      National Gov. Water Department and Catchment Management Agency   Responsible for water resource management Data Consult Operational Improvement Summary Data Recommendations Changes to Permits Water Service Provision Contract Abstraction Permits -monitoring requirements Hydrogeologist Engineer Specialists Figure 1 Institutional relationships and flow of data Figure 2. Aquimon user interfaceRAVENSCROFT221 MONITORING INTERVAL WATER LEVEL STATUS WATER QUALITY STATUS? Daily B B?  Borehole STATUS A Weekly B B?  Abstraction within recommended limits Bi weekly B B?  Water level recovery in short and long term Monthly B B?  No Water Quality Problems  Bi monthly A B?  Minimum Monitoring needed 6 Monthly A B?  Borehole STATUS B Yearly A A?  Water level and abstraction monitoring recommended None A A  OR Water Quality monitoring recommended Lessons from the fieldGet it right from the startIt is important to implement monitoring friendly projectsthat are correctly equipped from the start rather than try toretrofit installations. Besides being cheaper to do when theproject is being built, it is usually easier to access finance atthe construction stage rather than during the O&M phase.In addition, as part of the water project implementation,potential operators must be trained in taking and recordingreadings of water levels and abstraction. The training mustinclude practical testing of the operators’ ability to takeaccurate readings and to correctly record them in thelogbook. Operation and maintenance training for theinstitution that will be managing the water scheme mustinclude an overview of the need for ground water monitor-ing and awareness of issues related to ground water use. Inaddition, ground water monitoring must be incorporatedinto the management system for the scheme and mustinclude: checking the monitoring activities of the operator;reporting to and forwarding data to the local authority andmaintaining the monitoring equipment.Integrate with regular operation and maintenanceactivitiesMonitoring of the water resource needs to be integratedwith the regular activities of O&M staff at the individualscheme level. The pump operators’ job description needs toinclude the following tasks:• Measuring and recording water levels• Reading water meters and recording abstraction• Recording any other significant information related tothe borehole and the pump in the logbook. This wouldtypically include information like: if a flow meter orhour meter was faulty; if the borehole was pumping lesswater than normal; excessive noise from the borehole;leaks etc.• Submission of the data to the local authority office ona regular basis. It is recommended that this be doneevery two months unless required on a more frequentbasis. If a borehole/aquifer has the potential to bestressed and the demand from the borehole is close to itsmaximum yield, supply of the data on a monthly or evenweekly basis may be necessary.Groundwater monitoring should be part of a monitoringsystem that includes all aspects of a scheme’s operation. Fora sustainable scheme one cannot just monitor the groundwater and not other vital activities like the servicing ofdiesel engines, determining the water balance and waterlosses, cleaning of reservoirs, establishing tap water qual-ity, general network maintenance activities and the per-formance of the operators.Only process useable dataLog books should be kept for all boreholes - but detailedmonitoring of the data is only done for selected boreholeswhere there is a potential over-abstraction or water qualityproblem. The management system allows one to classifyboreholes into two classes:- boreholes not critical to moni-tor and boreholes that require regular monitoring. Theclass of borehole is based upon the frequency of recom-mended monitoring using the criteria listed below:Integration with other water resourcemanagement institutionsThe national water department and catchment manage-ment agencies are responsible for national and regionalwater resource management respectively. Data from moni-toring at the local level needs to be made available to theseinstitutions but it is important not overload them with datathat they do not need and cannot process. To accommodatethis the management system provides a summary of annualdata and additional data that can be obtained if required.A case study of tambo villageTambo is a settlement of about 3000 people and is suppliedby two boreholes. The one borehole, TAM2 supplies a340KL storage reservoir and the other, TAM1 pumpsdirectly into the reticulation system.When the project team first visited the village, the TAM1borehole was equipped with a positive displacement pumpthat would pump for about two minutes until the cut offprobe in the borehole stopped the pump. It would thenrecover for about another 3 minutes before switching onagain. It was immediately recommended that the pumpingrate be reduced from 1.8l/s to 1.0l/s for 18 hours a day andthat the total daily abstraction should be limited to 70kl aday. The pump was not immediately changed and eventu-ally burnt out.At this point the team again recommended a change ofthe pump size and the pump was replaced with a centrifugalpump that supplies approximately 0.8 l/s.Subsequent to the pump replacement, members of theproject team were informed while on site that there wasinsufficient water being supplied at Tambo village. Furtherinvestigation showed that the pumps were both only pump-ing for 20% to 30% of the time and that this had been setby a contracted electrician. Again recommendations weremade by the project team and the timers were reset to pumpfor 19 hours and 24 hours a day.Figure 3 shows that the water levels are responding wellto the abstraction at the new discharge rate. Wherepreviousely the pumping water level was 43mbgl and therest water level was 23mbgl, they are now 20.6 andRAVENSCROFT222Groundwater management is a relatively cheap andsimple way to improve the sustainability of water schemes,especially when integrated with the management of opera-tions and maintenance.PHILLIP RAVENSCROFT, praven@csir.co.za19.7mbgl respectively. Figure 4 shows that after the boreholewas set to pump at an appropriate abstraction rate inAugust 2001, the water levels started to recover and are nolonger a threat to the pump.ConclusionsGroundwater management can prevent pumps from oper-ating inefficiently and can prevent pump failure.Figure 3. Adjusted pumping routineFigure 4. Water level and average daily abstraction

Managing rural groundwater supplies

https://repository.lboro.ac.uk/articles/Managing_rural_groundwater_supplies/9588056/files/17227115.pdf

Managing rural groundwater supplies

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