BGS Visit to the Bikita Emergency Water Supply Project. 1. Background.

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1 BGS Visit to the Bikita Emergency Water Supply Project. 1. Background. In response to severe drought conditions currently affecting southern parts of Zimbabwe the British Government funded the Bikita District Emergency Water Supply Project. This project includes deepening of hand dug wells, rehabilitation of boreholes and drilling new boreholes. Initiated in August 1992 the project is scheduled for 9 months duration. The project area of Bikita and Matsai communal lands (see fig 1) is underlain by hard gneissic and granitic rocks of Precambrian age intruded by younger dolerites. Such rocks have a very low intrinsic hydrogeological development potential but when weathered form minor aquifers that may contain enough groundwater to supply the needs of small rural communities. During extended periods of drought the depleted water resources of such aquifers commonly form the only source of water for villages. Therefore some understanding of how much groundwater is present within these aquifers under the present harsh climatic conditions must be obtained if the long term sustainability of rural communities dependent upon such water supplies can be assessed. The Bikita Emergency Water Supply Project includes drilling and construction of 67 new boreholes. These boreholes need to be located with care if they are to supply sufficient groundwater to sustain dependant communities. Data obtained from the drilling and testing of these boreholes, located at widely distributed points throughout the Bikita District, should provide an indication of how the weathered basement aquifer system behaves under extreme drought conditions. The British Geological Survey (BGS) was requested to assess the ability of the consultant engaged by the District Development Fund (DDF) and the National Action Committee (NAC) to undertake drill site location and drilling supervision of the 67 new boreholes. An assessment of the drilling procedures used by the drilling contractor was also requested. 2. Visits Undertaken October Harare. The BGS representative arrived in Harare from Fiji on 1st October At a meeting held with Mr M Edwards, second secretary (Aid) at the British High Commission he was appraised of the local situation following the visit to the Bikita area of the Minister for Overseas Development, Baroness Chaulker. Prior to her visit rapid mobilisation of the drilling contractor and siting/ supervising consultant to the field had been undertaken with five boreholes being sited and drilled. This in essence proved the good faith of the parties involved in the absence of formal contracts.

2 The BGS officer discussed the project in detail with the Water Aid project co-ordinator, Mr Antony Waterkeyn. The involvement of the DDF at Provincial and District level was described. All project field operations are controlled at district level by a DDF project manager located at Bikita. DDF provincial staff located at Masvingo supervise the work programme and control allocation of funds. Procurement of equipment and mobilisation of consultants and contractors is undertaken with the advice of the NAC, Water Aid and ODA. By using the offices of Water Aid much more rapid procurement of equipment and materials can be achieved than by going through the normal government channels. Representatives of the borehole siting/drilling supervising consultants Groundwater Development Consultants (GDC) were met at the Water Aid offices in Harare. This is a Harare based consultancy of Zimbabwean nationals all of whom have public and private service experience. The inputs of the consultancy to the borehole drilling component of the project were discussed with the hydrogeologist/ geophysicist responsible for borehole site location and the sociologist/ economist designate. The hydrogeologist responsible for drilling supervision was not present. Procedures used by the geophysicist both in office and field for borehole site location were discussed as were his past experience of project work. The input of the sociologist was not the direct concern of the BGS representative, since prior to this meeting the project co-ordinator had indicated that DDF no longer required his, the sociologist's services. The content of the borehole drilling element of the project was discussed with the local manager of the drilling contractor Unidrilling at offices in Harare where the capabilities of the parent company, a major conglomeration of drilling and related firms, were also discussed th October Masvingo and Bikita Areas. During the period 6-14th October the BGS representative was based in Masvingo Province where he was able to undertake discussions with project staff at Provincial and District level and undertake field visits to the project area. At the DDF Masvingo office discussions were held with the provincial planning staff co-ordinating the various inputs to the project. Opportunity was also taken to discuss the nature of the DDF groundwater data base with Mr W Haberwik, a senior adviser with the IRWSSP. At the Bikita District offices the project content was discussed with the district administrator and his assistant. Members of the project field management team based at Bikita were met. The latter accompanied the BGS officer on several field visits around the project area where they were able to demonstrate the sociological inputs into the pre-siting procedures used for the location of potential drilling sites. Visits were made to the very dry southern part of the

3 Bikita area and the not so dry area adjacent to Bikita Township. Hand dug well deepening, borehole equipping and water distribution using water bowsers were demonstrated to the BGS officer. The Agritex office provided necessary aerial photographs on loan. Latterly the BGS officer was able to accompany the siting consultant in the field where the latter was able to demonstrate the operation of surface electrical resistivity survey equipment and the analysis of data produced. The drilling equipment used by the drilling contractor was examined and discussions held with the Unidrilling training officer Mr Wim de Beer and several drilling supervisors at a site located south of Shabane. Opportunity was also taken to view a demonstration of TV video borehole logging undertaken within a borehole located near Chivi by a BGS research team. The flow of water from weathered horizons below the normal weathered basement aquifer zone was clearly demonstrated th October Harare. On his return to Harare the BGS officer reported his findings to Mr Mike Edwards (BHC), Mr Antony Waterkeyn (Water Aid) and members of the National Action Committee. He then discussed the content of the drilling and siting/supervision contracts with Mr Antony Waterkeyn, Mr Dave Heywood (NAC) and Mr George Nhunhama (MLAWD). The corrosive qualities of the Bikita groundwaters were discussed with Dr Peter Morgan (Blair Institute) who was particularly concerned about the rapid degradation of substandard quality galvanised steel riser pipes supplied from Kenya under such conditions. Mr Heywood concluded that there is plenty of appropriate equipment available in Zimbabwe, it is expertise that is lacking for the collection and analysis of good quality hydrogeological data. A prototype plastic Bush Pump cylinder was examined as was the manufacture of "B" type Bush pumps, Wonder drills, windlasses, buckets and gin-poles at V and M Engineering in Harare st October Masvingo and Bikita Areas. Drove from Harare to Masvingo where met members of the ODA project review mission team. The BGS hydrofracking team demonstrated their down the hole TV video logging equipment to the members of the review team. 19th October. Following a visit to the Masvingo DDF office for a short project progress appraisal the team were introduced to the Provincial Administrator. At Bikita the team met the Assistant District Administrator before being given a detailed account of works undertaken to date by Mr Martyn Nyamanyru (DDF/project field manager). A field visit was

4 then made to view completed boreholes, possible rain-water harvesting sites at two schools and a well sinking team in action. At the last deepening of the well to 24 metres using blasting had produced a yield of 70x50l buckets of water per day. The rationing of water at well sites appears to have become the norm with the pump handle being replaced three times a day regardless of how good a well might be, to the detriment of potential garden plot developments at some sites. The team latterly drove to the north-western Bikita area to observe the drilling of two boreholes. The first drilled in hard quartzitic gneiss proved to be dry while the second being drilled into a very weathered granite looked as though it could yield an appreciable supply of water on completion. 20th October. Following a meeting of the team with the District Administrator at Bikita the team undertook a field visit to the Matsai area. At Chiremwaremwa School the team saw school children receive supplementary food, the construction of substandard Blair type pit latrines, discussed the possibilities of constructing a rainwater harvesting system utilising the school roofs and inspected a dry borehole. Near Mashoko two hand dug wells equipped with type "B" Bush pumps were inspected. At a third site a borehole yielding fairly corrosive water was studied. A well siting team were observed in action at Mukanga school. Several of the team took the opportunity to visit the Siri Dam site from which irrigation water is supplied in normal years for the irrigation of lands downstream along the Turwi Valley. 21st October. At Bikita the BGS officer was able to interview Mr Joseph Njaniki, the borehole siting consultant. Of the 11 sites he was able to assess during the last week only 6 had proved to be suitable for drilling. Mr Njaniki realised the commitment that he has to make to the project promising to have a second well siting team in place in Bikita as soon as possible. The BGS officer then rejoined the rest of the Review Team at a round-up meeting with the District Project subcommittee. Here the question of the capabilities of the consultants, GDC, were brought into question. The ODA team suggested that the project management should continue using the consultants but should consider using the services of BGS to supervise the initial part of the drilling exercise until the siting exercise had been completed when GDC would take over the former. A small committee was organised to discuss the content of contracts for the consultant and the drilling contractor. The BGS officer flew back to Harare at the end of the Emergency Water Supply Project appraisal nd October Harare. At the MLAWD office in Harare the BGS officer discussed the conduct of the GDC consultants with Mr George Nhunhama

5 (hydrogeologist). He was advised that while his attitude of employing qualified local consultants on contract work was progressive the consultants so employed had to ensure that they undertook assignments expeditiously, with a serious commitment to completing the work as rapidly as possible and to an acceptable standard. The reservations of DDF and review team personnel as to the capabilities of GDC were expressed. Mr Nhunhama promised to consult GDC on these matters. At the office of Dwyers in Harare the BGS office met the designated drilling supervision consultant from GDC. He was thoroughly appraised of the current position of GDC on the project. After producing excuses for his nonappearance based upon transport failures he assured the BGS officer that he would undertake the works required at Bikita as soon as possible. 3. Discussion of Findings Project Management at District Level. Considering their lack of formal qualifications and suitable training the two DDF officers attached to the project, Mr Nyamanyaro and Mr Magura work well. Their shortcomings include a lack of appreciation of the modes of groundwater occurrence and quality variations within the weathered Basement aquifer system. They could learn much during this project given proper expert inputs thereby becoming valuable members of the DDF district team. Both are extremely enthusiastic but lack leadership in technical and mechanical matters Siting Consultant. The siting consultant demonstrated lack of commitment to the project that could have been due to his being married just before the arrival of the BGS officer in the Bikita area as well as lack of a formal contract. On his belated arrival at Bikita he demonstrated a lack of preparedness. Having been supplied with the grid references of the 67 pre-sites he had neither 1: map sheets nor aerial photographs of the relevant areas for site location. Suitable maps with sites located as well as aerial photographs on loan from Agritex were provided by the BGS officer. In the field he demonstrated his equipment and survey procedures to the BGS officer. The ABEM SAS 300 Terrameter employed has limited survey capacity lacking a booster unit while the reels and ancillary cables used are in need of maintenance. However he was able to demonstrate a reasonably rapid field survey technique with a well trained crew, data being manipulated and plotted during the survey ensuring that anomalies would be recognised at once. The maximum AB spread length employed was 180 metres, limited by the input power of the equipment used. However there was a tendency to cut short the survey on indication of solid rock penetration being obtained. He employed the Sclumberger form of electrode configuration which requires the measurement of at least two

6 determinations at MN potential electrode cross overs, he only did the one. He also demonstrated a lack of understanding of data analysis techniques, but this was found to be due to a lack of adequate training on the part of an expatriate consultant employed by government. After consultation with Mr Dave Heywood of NAC the BGS officer concluded that despite the obvious shortcomings in equipment availability and maintenance and the consultant's lack of data analysis skills he was "as good as one could find in Zimbabwe", a fact demonstrated by at least one of the higher priced tendering consultants wanting to employ GDC on a subcontract basis. He demonstrated successfully that he can undertake a rapid assessment of the three priority sites located at each location, with a depth probe undertaken at each within a two hour period. He should therefore be able to assess at least 3 sites per day. Given some commitment on his part he could assess all remaining 62 sites within a one month period Drilling Supervision Consultant. The designated consultant was belatedly available for consultation in Harare where only limited assessment of his capabilities could be made. The BGS officer had worked with the designated consultant when the latter was a trainee hydrogeologist with MEWRD at Romsley and Inyamazura in Although he now has a PhD it is felt that he more suited to an academic environment rather than the "hands on" of drilling supervision and geological logging. The BGS officer therefore has reservations about this consultant's field capabilities and his belated assurances that he would undertake the required fieldwork in Bikita as soon as possible Drilling Contractor. Discussions about the nature of the contracting company and its associates within a multinational combine based in South Africa were held in the company's offices in Harare. An example of the drilling unit to be used on project work was viewed at a roadside location south of Zvishavane. The drilling rig was a high pressure Rock Giant down the hole hammer rig mounted on a 10 ton capacity 4x2 Hino truck. Given wet weather conditions it could prove difficult to move the rig on and off site at localities within Bikita. A 4x4 Mercedes support vehicle carries a 750 cfm x 350 psi compressor and 20 number x 20 feet x 4.5" API drill rods. Carried on the rig was one high pressure 6" hammer, two 6.5" and two 8.5" button bits, a welding set, a button grinding set and an auxiliary diesel engine to power the rig. In addition there were several broken 8.5" and 6.5" button bits. A second spare 6" hammer was not available. There was no dust extraction equipment. Fuel and lubricants are normally conveyed to site in a third maintenance vehicle. The basic system is typical of a better than average South African drilling unit. The drilling units were apparently

7 obtained second hand from a drilling company based in Kuruman several months ago. Local black South African personnel operate the drilling rig under the supervision of a white South African tool pusher. 4. Conclusions and Recommendations. Given the time constraints of the project, the limited technical aspects of consultant, contractor and management team all that can be realistically expected is the drilling and construction of 67 boreholes in as short a time frame as possible barring any major mechanical breakdowns or heavy rainfall. Obtaining realistic quantities of geological and hydrogeological data required to assess the sustainability of the groundwater resources will be very difficult given the lack of expertise. It is recommended that initially the siting consultant be used to prove which of the three localities pre-selected by villagers and DDF personnel at each site is the most viable. If none of the three prove to be viable the more detailed examination of that site must be undertaken at the conclusion of the pre-site assessment exercise. This should enable a reasonable number of sites to be assessed and made available to the drilling contractor who will then be able to proceed with drilling as quickly as possible. This will depend totally upon the commitment of the siting consultant who should be penalised if the drillers have to wait for suitable sites, standing time being chargeable. Hopefully drilling supervision can be undertaken by the consultant but should this not be possible DDF will have to supply a suitable person. He must undertake the description of all geological samples collected at 0.5 metre intervals during borehole drilling. Using this information the supervisor will be able to advise the driller how much casing will be required to case off the upper unstable weathered horizon. He will also be able to advise the driller at what depth drilling should be discontinued. In the absence of a supervisor an arbitery standard depth of 60 metres per hole could be applied with the rig tool pusher be made responsible for the recording of drill penetration rate and flow log data, collection of geological samples and deciding to what depth casing should be installed. This situation would mean the driller self certifying as correct work that he has undertaken, a wholly unsatisfactory condition. On completion of the above works each borehole should be accurately test pumped to provide some indication of the sustainability of the groundwater resource under the present drought conditions. The quality of the water produced should also be assessed given the number of pumps and wells that have failed in the Bikita area within 4 years of installation due to the effects of active corrosion of metal fittings, pipes and casings.

8 If the contractor, consultant and management teams all interact correctly then there should be no reason, other than heavy sustained rainfall, why a series of 60+ successful boreholes should not be drilled and constructed rapidly within the time frame of the next 3 months. However the quality of hydrogeological data collected during this exercise is very much in doubt. This would be very unfortunate since such data could form a viable data base for a proposed much larger follow on water development project. The ODA Review Team suggest that should the consultants fail to provide drilling sites in sufficient numbers due to site re-evaluation being necessary at a large number of locations then the BGS officer could be made available to supervise the drilling of an initial series of boreholes. This would ensure that the momentum of the project is not lost. Some attempt should be made to assess the Mujiche sand river bed as a possible source of water, abstracted via a collector well system, for schools currently receiving water by Water Aid bowser from a source located on the Bikita to Birchenough Bridge road. Such a central site of supply would reduce cartage costs and supply times.