OR/15/019 Pilot study results - Revision history

Dbk: /* Technical investigations */

2015-07-28T10:43:16Z

Technical investigations

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Dbk: /* Technical investigations */

2015-07-28T10:38:24Z

Technical investigations

← Older revision		Revision as of 11:38, 28 July 2015
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	Pumping tests indicated the aquifer transmissivity (T) to range from 0.01 to >100 m2/d. Transmissivity measured from pumping tests in boreholes which included a screened section in the regolith aquifer ranged 0.01 to 15 m<sup>2</sup>/d. In the boreholes which entirely cased out the regolith, and in which a pumping test was possible, transmissivity was indicated to be highly variable ranging from <1 to 632 m<sup>2</sup>/d — Figure 11. At three water points transmissivity was too low to conduct a pumping test at a discharge rate of 0.5 l/s. Bailer tests at these points indicated the resource potential to be sufficient to sustainably support a hand pump. Two of these water points showed a primary symptom of failure of insufficient yield, suggesting other factors such as borehole design and construction or poor siting could be more significant to the low yield than the absolute groundwater availability. A range of borehole designs were observed, in which two cased out the weathered regolith, and one included some screen section within the regolith horizon, as discussed below.		Pumping tests indicated the aquifer transmissivity (T) to range from 0.01 to >100 m2/d. Transmissivity measured from pumping tests in boreholes which included a screened section in the regolith aquifer ranged 0.01 to 15 m<sup>2</sup>/d. In the boreholes which entirely cased out the regolith, and in which a pumping test was possible, transmissivity was indicated to be highly variable ranging from <1 to 632 m<sup>2</sup>/d — Figure 11. At three water points transmissivity was too low to conduct a pumping test at a discharge rate of 0.5 l/s. Bailer tests at these points indicated the resource potential to be sufficient to sustainably support a hand pump. Two of these water points showed a primary symptom of failure of insufficient yield, suggesting other factors such as borehole design and construction or poor siting could be more significant to the low yield than the absolute groundwater availability. A range of borehole designs were observed, in which two cased out the weathered regolith, and one included some screen section within the regolith horizon, as discussed below.

	Other work in crystalline basement complex aquifers in sub‐Saharan Africa across a range of climates has found there can be sufficient storage and transmissivity in the weathered bedrock and overlying regolith to support handpump supplies (Chilton and Smith‐Carington 1984<ref name=Chiltern 1984">Chilton PJ & Smith‐Carington A. 1984. Characteristics of the weathered basement aquifer in relation to rural water supplies. . In: Challenges in African Hydrology and Water Resources. Proceedings of Harare Symposium, IAHS Publication 144, 57–72. </ref>; Chilton and Foster 1995<ref name="Chiltern 1995">Chilton PJ & Foster SSD. 1995. Hydrogeological characterisation and water supply potential of basement aquifers in tropical Africa. ''Hydrogeology Journal ''3: 1, 36''‐''49 </ref>; MacDonald et al. 2012<ref name="MacDonald 2012">MacDonald AM, Bonsor HC, Ó Dochartaigh BÉ and Taylor RG. 2012. Quantitative maps of groundwater resources in Africa. ''Environmental Research Letters, '''''7; '''024009. </ref>; Lapworth et al. 2013<ref name="Lapworth">Lapworth D J L. et al. 2012. Residence times of shallow groundwater in West Africa: implications for hydrogeology and resilience to future changes in climate, ''Hydrogeology Journal'', DOI 10.1007/s10040‐012‐0925‐4 </ref>). Based on borehole data from Malawi, Chilton and Smith‐Carington (1984)<ref name="Chiltern 1984"></ref> concluded that the regolith aquifer would usually support borehole yields sufficient for a handpump where its saturated thickness was greater than 10–15 m, provided the borehole design was appropriate for these conditions. Appropriate targeting of borehole design relies, however, on sound understanding of the local hydrogeological conditions.		Other work in crystalline basement complex aquifers in sub‐Saharan Africa across a range of climates has found there can be sufficient storage and transmissivity in the weathered bedrock and overlying regolith to support handpump supplies (Chilton and Smith‐Carington 1984<ref name=Chiltern 1984">Chilton PJ & Smith‐Carington A. 1984. Characteristics of the weathered basement aquifer in relation to rural water supplies. . In: Challenges in African Hydrology and Water Resources. Proceedings of Harare Symposium, IAHS Publication 144, 57–72. </ref>; Chilton and Foster 1995<ref name="Chiltern 1995">Chilton PJ & Foster SSD. 1995. Hydrogeological characterisation and water supply potential of basement aquifers in tropical Africa. ''Hydrogeology Journal ''3: 1, 36''‐''49 </ref>; MacDonald et al. 2012<ref name="MacDonald 2012">MacDonald AM, Bonsor HC, Ó Dochartaigh BÉ and Taylor RG. 2012. Quantitative maps of groundwater resources in Africa. ''Environmental Research Letters, '''''7; '''024009. </ref>; Lapworth et al. 2013<ref name="Lapworth">Lapworth D J L. et al. 2012. Residence times of shallow groundwater in West Africa: implications for hydrogeology and resilience to future changes in climate, ''Hydrogeology Journal'', DOI 10.1007/s10040‐012‐0925‐4 </ref>). Based on borehole data from Malawi, Chilton and Smith‐Carington (1984)<ref name="Chiltern 1984">Chilton P J & Smith‐Carington A. 1984. Characteristics of the weathered basement aquifer in relation to rural water supplies. . In: Challenges in African Hydrology and Water Resources. ''Proceedings of Harare Symposium, IAHS Publication'' 144, 57–72. </ref> concluded that the regolith aquifer would usually support borehole yields sufficient for a handpump where its saturated thickness was greater than 10–15 m, provided the borehole design was appropriate for these conditions. Appropriate targeting of borehole design relies, however, on sound understanding of the local hydrogeological conditions.

	[[Image:15019_fig13.jpg\|thumb\|center\|300px\| '''Figure 13''' Borehole designs observed from CCTV surveys in the field: (Left) Modified open hole design, with the borehole screened in the shallow weathered aquifer; (Right) traditional open‐hole design, with the shallow weathered aquifer entirely cased out, and a narrower hole diameter with depth in the bedrock.]]		[[Image:15019_fig13.jpg\|thumb\|center\|300px\| '''Figure 13''' Borehole designs observed from CCTV surveys in the field: (Left) Modified open hole design, with the borehole screened in the shallow weathered aquifer; (Right) traditional open‐hole design, with the shallow weathered aquifer entirely cased out, and a narrower hole diameter with depth in the bedrock.]]

Dbk: /* Technical investigations */

2015-07-28T10:37:05Z

Technical investigations

← Older revision		Revision as of 11:37, 28 July 2015
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	Pumping tests indicated the aquifer transmissivity (T) to range from 0.01 to >100 m2/d. Transmissivity measured from pumping tests in boreholes which included a screened section in the regolith aquifer ranged 0.01 to 15 m<sup>2</sup>/d. In the boreholes which entirely cased out the regolith, and in which a pumping test was possible, transmissivity was indicated to be highly variable ranging from <1 to 632 m<sup>2</sup>/d — Figure 11. At three water points transmissivity was too low to conduct a pumping test at a discharge rate of 0.5 l/s. Bailer tests at these points indicated the resource potential to be sufficient to sustainably support a hand pump. Two of these water points showed a primary symptom of failure of insufficient yield, suggesting other factors such as borehole design and construction or poor siting could be more significant to the low yield than the absolute groundwater availability. A range of borehole designs were observed, in which two cased out the weathered regolith, and one included some screen section within the regolith horizon, as discussed below.		Pumping tests indicated the aquifer transmissivity (T) to range from 0.01 to >100 m2/d. Transmissivity measured from pumping tests in boreholes which included a screened section in the regolith aquifer ranged 0.01 to 15 m<sup>2</sup>/d. In the boreholes which entirely cased out the regolith, and in which a pumping test was possible, transmissivity was indicated to be highly variable ranging from <1 to 632 m<sup>2</sup>/d — Figure 11. At three water points transmissivity was too low to conduct a pumping test at a discharge rate of 0.5 l/s. Bailer tests at these points indicated the resource potential to be sufficient to sustainably support a hand pump. Two of these water points showed a primary symptom of failure of insufficient yield, suggesting other factors such as borehole design and construction or poor siting could be more significant to the low yield than the absolute groundwater availability. A range of borehole designs were observed, in which two cased out the weathered regolith, and one included some screen section within the regolith horizon, as discussed below.

	Other work in crystalline basement complex aquifers in sub‐Saharan Africa across a range of climates has found there can be sufficient storage and transmissivity in the weathered bedrock and overlying regolith to support handpump supplies (Chilton and Smith‐Carington 1984<ref name=Chiltern 1984">Chilton PJ & Smith‐Carington A. 1984. Characteristics of the weathered basement aquifer in relation to rural water supplies. . In: Challenges in African Hydrology and Water Resources. Proceedings of Harare Symposium, IAHS Publication 144, 57–72. </ref>; Chilton and Foster 1995<ref name="Chiltern 1995">Chilton PJ & Foster SSD. 1995. Hydrogeological characterisation and water supply potential of basement aquifers in tropical Africa. ''Hydrogeology Journal ''3: 1, 36''‐''49 </ref>; MacDonald et al. 2012<ref name="MacDonald 2012">MacDonald AM, Bonsor HC, Ó Dochartaigh BÉ and Taylor RG. 2012. Quantitative maps of groundwater resources in Africa. ''Environmental Research Letters, '''''7; '''024009. </ref>; Lapworth et al. 2013<ref></ref>). Based on borehole data from Malawi, Chilton and Smith‐Carington (1984)<ref name="Chiltern 1984"></ref> concluded that the regolith aquifer would usually support borehole yields sufficient for a handpump where its saturated thickness was greater than 10–15 m, provided the borehole design was appropriate for these conditions. Appropriate targeting of borehole design relies, however, on sound understanding of the local hydrogeological conditions.		Other work in crystalline basement complex aquifers in sub‐Saharan Africa across a range of climates has found there can be sufficient storage and transmissivity in the weathered bedrock and overlying regolith to support handpump supplies (Chilton and Smith‐Carington 1984<ref name=Chiltern 1984">Chilton PJ & Smith‐Carington A. 1984. Characteristics of the weathered basement aquifer in relation to rural water supplies. . In: Challenges in African Hydrology and Water Resources. Proceedings of Harare Symposium, IAHS Publication 144, 57–72. </ref>; Chilton and Foster 1995<ref name="Chiltern 1995">Chilton PJ & Foster SSD. 1995. Hydrogeological characterisation and water supply potential of basement aquifers in tropical Africa. ''Hydrogeology Journal ''3: 1, 36''‐''49 </ref>; MacDonald et al. 2012<ref name="MacDonald 2012">MacDonald AM, Bonsor HC, Ó Dochartaigh BÉ and Taylor RG. 2012. Quantitative maps of groundwater resources in Africa. ''Environmental Research Letters, '''''7; '''024009. </ref>; Lapworth et al. 2013<ref name="Lapworth">Lapworth D J L. et al. 2012. Residence times of shallow groundwater in West Africa: implications for hydrogeology and resilience to future changes in climate, ''Hydrogeology Journal'', DOI 10.1007/s10040‐012‐0925‐4 </ref>). Based on borehole data from Malawi, Chilton and Smith‐Carington (1984)<ref name="Chiltern 1984"></ref> concluded that the regolith aquifer would usually support borehole yields sufficient for a handpump where its saturated thickness was greater than 10–15 m, provided the borehole design was appropriate for these conditions. Appropriate targeting of borehole design relies, however, on sound understanding of the local hydrogeological conditions.

	[[Image:15019_fig13.jpg\|thumb\|center\|300px\| '''Figure 13''' Borehole designs observed from CCTV surveys in the field: (Left) Modified open hole design, with the borehole screened in the shallow weathered aquifer; (Right) traditional open‐hole design, with the shallow weathered aquifer entirely cased out, and a narrower hole diameter with depth in the bedrock.]]		[[Image:15019_fig13.jpg\|thumb\|center\|300px\| '''Figure 13''' Borehole designs observed from CCTV surveys in the field: (Left) Modified open hole design, with the borehole screened in the shallow weathered aquifer; (Right) traditional open‐hole design, with the shallow weathered aquifer entirely cased out, and a narrower hole diameter with depth in the bedrock.]]

Dbk at 10:36, 28 July 2015

2015-07-28T10:36:07Z

Show changes

Dbk at 10:49, 26 June 2015

2015-06-26T10:49:46Z

← Older revision		Revision as of 11:49, 26 June 2015
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	''Groundwater residence time indicators''<br>The analysis of dissolved anthropogenic gas concentrations (CFC, SF6) indicates a difference in the ages of the waters abstracted from the water points. Half of the water points sampled are indicated to yield groundwater with a residence time less than 10 years old, whilst the other half of the water points yield groundwater which has a residence time of over 30 years old – Figure 15. This difference is most likely attributable to the difference in the borehole designs of the water points. Four out of the five samples which are indicated to have a residence time less than 10 years were from boreholes which contained a screened section within the shallow regolith. Inflows of shallow groundwater, which will be recharged from recent seasonal rainfall, will therefore inflow the borehole. These inflows were observed from the CCTVs in most cases in these boreholes.		''Groundwater residence time indicators''<br>The analysis of dissolved anthropogenic gas concentrations (CFC, SF6) indicates a difference in the ages of the waters abstracted from the water points. Half of the water points sampled are indicated to yield groundwater with a residence time less than 10 years old, whilst the other half of the water points yield groundwater which has a residence time of over 30 years old – Figure 15. This difference is most likely attributable to the difference in the borehole designs of the water points. Four out of the five samples which are indicated to have a residence time less than 10 years were from boreholes which contained a screened section within the shallow regolith. Inflows of shallow groundwater, which will be recharged from recent seasonal rainfall, will therefore inflow the borehole. These inflows were observed from the CCTVs in most cases in these boreholes.

	[[Image:~~OR15019_fig15~~.jpg\|thumb\|center\|300px\| '''Figure 15''' Analysis of CFC and SF6 data showing a bimodal age group between samples.]]		[[Image:15019_fig15.jpg\|thumb\|center\|300px\| '''Figure 15''' Analysis of CFC and SF6 data showing a bimodal age group between samples.]]
	Four of the five water samples which are indicated to have a longer residence time of over 30 years, were all collected from boreholes which cased out the shallow regolith entirely, and therefore the borehole could only abstract groundwater stored within the weathered and underlying fractured bedrock.		Four of the five water samples which are indicated to have a longer residence time of over 30 years, were all collected from boreholes which cased out the shallow regolith entirely, and therefore the borehole could only abstract groundwater stored within the weathered and underlying fractured bedrock.

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	Corrosion of the handpump materials is most likely due to use of galvanised iron in groundwater of slightly low pH. Corrosion of the GI materials will contribute to the high dissolved iron content of the water, as shown by the groundwater chemistry data in the previous section. The widespread corrosion problem indicates GI is not a suitable material for handpump installations in this region. Furthermore, in relation to the ascetic and taste acceptability of iron‐rich groundwater, the use of mild steel borehole casing and galvanised pump components can make an existing natural groundwater quality constraint significantly worse (Lewis and Chilton, 1989).		Corrosion of the handpump materials is most likely due to use of galvanised iron in groundwater of slightly low pH. Corrosion of the GI materials will contribute to the high dissolved iron content of the water, as shown by the groundwater chemistry data in the previous section. The widespread corrosion problem indicates GI is not a suitable material for handpump installations in this region. Furthermore, in relation to the ascetic and taste acceptability of iron‐rich groundwater, the use of mild steel borehole casing and galvanised pump components can make an existing natural groundwater quality constraint significantly worse (Lewis and Chilton, 1989).

	[[Image:~~OR15019_fig16~~.jpg\|thumb\|center\|~~300px~~\| '''Figure 16''' (~~Top~~) corroded rising main thread; (~~Bottom~~) perforated rising main.]]		[[Image:15019_fig16.jpg\|thumb\|center\|600px\| '''Figure 16''' (left) corroded rising main thread; (right) perforated rising main.]]
	''Handpump repairs'': All of the water points are reported by the communities to have undergone some repair during their lifetime, the most common repairs being replacement of pipes, chains and the pump cylinder. Replacement of leaking or damaged rising main pipes had occurred at 9 of the 10 handpumps. In some cases this was reported to have been done by removal of the pipes – and thereby raising the pump cylinder by approximately 3 m for each pipe removed – or, by cutting out the corroded or damaged sections of the pipes and re‐threading the remaining shorter pipes. On removal and inspection of the handpumps, there was evidence of either removal of the pipes, or shortening of pipes to remove damaged sections, rather than proper pipe replacement – Figure 17. Only one of out the 41 pumping rods examined in the nine study sites, conformed to India Mark II specifications – Figure 17.		''Handpump repairs'': All of the water points are reported by the communities to have undergone some repair during their lifetime, the most common repairs being replacement of pipes, chains and the pump cylinder. Replacement of leaking or damaged rising main pipes had occurred at 9 of the 10 handpumps. In some cases this was reported to have been done by removal of the pipes – and thereby raising the pump cylinder by approximately 3 m for each pipe removed – or, by cutting out the corroded or damaged sections of the pipes and re‐threading the remaining shorter pipes. On removal and inspection of the handpumps, there was evidence of either removal of the pipes, or shortening of pipes to remove damaged sections, rather than proper pipe replacement – Figure 17. Only one of out the 41 pumping rods examined in the nine study sites, conformed to India Mark II specifications – Figure 17.

	[[Image:~~OR15019_fig17~~.jpg\|thumb\|center\|~~300px~~\| '''Figure 17''' (~~Top~~); frequency distribution of rising main lengths in mm (72 rising main lengths from 8 supplies examined); (~~Bottom~~) frequency distribution of pump rod lengths in mm (41 rods from 6 supplies examined).]]		[[Image:15019_fig17.jpg\|thumb\|center\|800px\| '''Figure 17''' (left); frequency distribution of rising main lengths in mm (72 rising main lengths from 8 supplies examined); (right) frequency distribution of pump rod lengths in mm (41 rods from 6 supplies examined).]]

	'''Summary'''<br>The data from the 10 sites provide a post construction audit of the failed water points and local community governance and management arrangements. The data indicate that in some cases the borehole design does not match the aquifer resource available; handpump materials are inappropriate and possibly of poor quality; there has been a lack of supervision of the construction of water points; siting processes are often inadequate; there are problems with recurrent finance to pay for operation and maintenance due to inability or unwillingness of households to pay; in many cases there is a lack of adequate training and capacity building of Water User Committees; there have also been some challenges in community‐based management such as enforcement of rules; most communities are unable to access higher‐level support to maintain water points. All of these factors are likely to contribute, to greater or lesser extents, to water point failure. The data from the community surveys and technical investigations are brought together in the following section and analysed using the diagnostic framework and RCA approach developed by the pilot study, to see if it is possible to identify the different significance of these factors to failure and the underlying root causes.		'''Summary'''<br>The data from the 10 sites provide a post construction audit of the failed water points and local community governance and management arrangements. The data indicate that in some cases the borehole design does not match the aquifer resource available; handpump materials are inappropriate and possibly of poor quality; there has been a lack of supervision of the construction of water points; siting processes are often inadequate; there are problems with recurrent finance to pay for operation and maintenance due to inability or unwillingness of households to pay; in many cases there is a lack of adequate training and capacity building of Water User Committees; there have also been some challenges in community‐based management such as enforcement of rules; most communities are unable to access higher‐level support to maintain water points. All of these factors are likely to contribute, to greater or lesser extents, to water point failure. The data from the community surveys and technical investigations are brought together in the following section and analysed using the diagnostic framework and RCA approach developed by the pilot study, to see if it is possible to identify the different significance of these factors to failure and the underlying root causes.

Dbk: /* Technical investigations */

2015-06-26T10:48:38Z

Technical investigations

← Older revision		Revision as of 11:48, 26 June 2015
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	Groundwater quality issues were observed at all but one of the failed water points and inadequate water quality was reported by the community to be the primary symptom of water point failure at six of the supplies.		Groundwater quality issues were observed at all but one of the failed water points and inadequate water quality was reported by the community to be the primary symptom of water point failure at six of the supplies.

	[[Image:~~15019_fig005~~.jpg\|thumb\|center\|700px\| '''Figure 14''' (left) opaque, milky appearance of groundwaters; (Middle) groundwater quality improved in some boreholes with pumping; (right) significant orange staining on borehole casing observed in all.]]		[[Image:15019_fig14.jpg\|thumb\|center\|700px\| '''Figure 14''' (left) opaque, milky appearance of groundwaters; (Middle) groundwater quality improved in some boreholes with pumping; (right) significant orange staining on borehole casing observed in all.]]

	Within the exception of one water point (A16), all the abstracted groundwater contained large quantities of suspended solids, and was opaque in appearance with a pale brown to orange hue – Figure 14. In some cases, the quality improved with pumping (Figure 14), but, with the exception of one site, none of the groundwaters attained a completely transparent appearance, and remained ‘milky’ in appearance.		Within the exception of one water point (A16), all the abstracted groundwater contained large quantities of suspended solids, and was opaque in appearance with a pale brown to orange hue – Figure 14. In some cases, the quality improved with pumping (Figure 14), but, with the exception of one site, none of the groundwaters attained a completely transparent appearance, and remained ‘milky’ in appearance.

Dbk: /* Technical investigations */

2015-06-26T10:48:19Z

Technical investigations

← Older revision		Revision as of 11:48, 26 June 2015
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	Other work in crystalline basement complex aquifers in sub‐Saharan Africa across a range of climates has found there can be sufficient storage and transmissivity in the weathered bedrock and overlying regolith to support handpump supplies (Chilton and Smith‐Carington 1984; Chilton and Foster 1995; MacDonald et al. 2012; Lapworth et al. 2013). Based on borehole data from Malawi, Chilton and Smith‐Carington (1984) concluded that the regolith aquifer would usually support borehole yields sufficient for a handpump where its saturated thickness was greater than 10‐15 m, provided the borehole design was appropriate for these conditions. Appropriate targeting of borehole design relies, however, on sound understanding of the local hydrogeological conditions.		Other work in crystalline basement complex aquifers in sub‐Saharan Africa across a range of climates has found there can be sufficient storage and transmissivity in the weathered bedrock and overlying regolith to support handpump supplies (Chilton and Smith‐Carington 1984; Chilton and Foster 1995; MacDonald et al. 2012; Lapworth et al. 2013). Based on borehole data from Malawi, Chilton and Smith‐Carington (1984) concluded that the regolith aquifer would usually support borehole yields sufficient for a handpump where its saturated thickness was greater than 10‐15 m, provided the borehole design was appropriate for these conditions. Appropriate targeting of borehole design relies, however, on sound understanding of the local hydrogeological conditions.
	[[Image:~~OR15019_fig13~~.jpg\|thumb\|center\|300px\| '''Figure 13''' Borehole designs observed from CCTV surveys in the field: (Left) Modified open hole design, with the borehole screened in the shallow weathered aquifer; (Right) traditional open‐hole design, with the shallow weathered aquifer entirely cased out, and a narrower hole diameter with depth in the bedrock.]]		[[Image:15019_fig13.jpg\|thumb\|center\|300px\| '''Figure 13''' Borehole designs observed from CCTV surveys in the field: (Left) Modified open hole design, with the borehole screened in the shallow weathered aquifer; (Right) traditional open‐hole design, with the shallow weathered aquifer entirely cased out, and a narrower hole diameter with depth in the bedrock.]]

	'''Borehole design and construction'''<br>The water points examined in the pilot study (boreholes with handpumps) were all constructed between 1997 and 2012; the majority being constructed between 2007 and 2009. Five of the boreholes have an open‐ hole design in which the weathered regolith is cased out completely and inflow to the borehole is entirely from the fractured bedrock – Figure 13. The other five have a modified open‐hole design, with the borehole being partially screened within the regolith, enabling inflow from this aquifer as well as the underlying fractured bedrock – Figure 13. In some cases, the drilling diameter in the bedrock was the same as that in the overburden, while in others a reduction in hole size is evident. All of the boreholes were cased with 5 inch (125 mm) uPVC casing, with the exception of the borehole constructed in 1997. The borehole depths ranged from 31 to 82 m (average depth 55 m). Two of the boreholes were measured as only 15 m deep, with the screened interval entirely within the weathered regolith. Siltation was apparent at the base of the boreholes, but in the absence of construction data for these it is impossible to know if the siltation has resulted in a significant reduction in the total borehole length. Significant siltation would indicate the boreholes had been inappropriately designed and/or poorly constructed and significant amounts of green‐ grey silt and fine sands have been able to enter, either through the screened sections in the regolith or around the base of the casing. Lesser amounts of siltation have probably occurred at the other sites, but could not be evaluated without knowing the original drilled depth of the boreholes. One of the boreholes was reported by the community to have partially collapsed due to inadequate installation of the casing.		'''Borehole design and construction'''<br>The water points examined in the pilot study (boreholes with handpumps) were all constructed between 1997 and 2012; the majority being constructed between 2007 and 2009. Five of the boreholes have an open‐ hole design in which the weathered regolith is cased out completely and inflow to the borehole is entirely from the fractured bedrock – Figure 13. The other five have a modified open‐hole design, with the borehole being partially screened within the regolith, enabling inflow from this aquifer as well as the underlying fractured bedrock – Figure 13. In some cases, the drilling diameter in the bedrock was the same as that in the overburden, while in others a reduction in hole size is evident. All of the boreholes were cased with 5 inch (125 mm) uPVC casing, with the exception of the borehole constructed in 1997. The borehole depths ranged from 31 to 82 m (average depth 55 m). Two of the boreholes were measured as only 15 m deep, with the screened interval entirely within the weathered regolith. Siltation was apparent at the base of the boreholes, but in the absence of construction data for these it is impossible to know if the siltation has resulted in a significant reduction in the total borehole length. Significant siltation would indicate the boreholes had been inappropriately designed and/or poorly constructed and significant amounts of green‐ grey silt and fine sands have been able to enter, either through the screened sections in the regolith or around the base of the casing. Lesser amounts of siltation have probably occurred at the other sites, but could not be evaluated without knowing the original drilled depth of the boreholes. One of the boreholes was reported by the community to have partially collapsed due to inadequate installation of the casing.
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	Groundwater quality issues were observed at all but one of the failed water points and inadequate water quality was reported by the community to be the primary symptom of water point failure at six of the supplies.		Groundwater quality issues were observed at all but one of the failed water points and inadequate water quality was reported by the community to be the primary symptom of water point failure at six of the supplies.

	[[Image:~~OR15019_fig14~~.jpg\|thumb\|center\|~~300px~~\| '''Figure 14''' (~~Top~~) opaque, milky appearance of groundwaters; (Middle) groundwater quality improved in some boreholes with pumping; (~~Bottom~~) significant orange staining on borehole casing observed in all.]]		[[Image:15019_fig005.jpg\|thumb\|center\|700px\| '''Figure 14''' (left) opaque, milky appearance of groundwaters; (Middle) groundwater quality improved in some boreholes with pumping; (right) significant orange staining on borehole casing observed in all.]]

	Within the exception of one water point (A16), all the abstracted groundwater contained large quantities of suspended solids, and was opaque in appearance with a pale brown to orange hue – Figure 14. In some cases, the quality improved with pumping (Figure 14), but, with the exception of one site, none of the groundwaters attained a completely transparent appearance, and remained ‘milky’ in appearance.		Within the exception of one water point (A16), all the abstracted groundwater contained large quantities of suspended solids, and was opaque in appearance with a pale brown to orange hue – Figure 14. In some cases, the quality improved with pumping (Figure 14), but, with the exception of one site, none of the groundwaters attained a completely transparent appearance, and remained ‘milky’ in appearance.

Dbk: /* Technical investigations */

2015-06-26T10:47:32Z

Technical investigations

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	==Technical investigations==		==Technical investigations==
	[[Image:15019_fig004.jpg\|thumb\|center\|~~300px~~\| Bailer (left) and pumping tests (right) being carried out in Amuria District.]]		[[Image:15019_fig004.jpg\|thumb\|center\|600px\| Bailer (left) and pumping tests (right) being carried out in Amuria District.]]

	The main technical findings of the fieldwork are summarised below.		The main technical findings of the fieldwork are summarised below.

Dbk at 10:47, 26 June 2015

2015-06-26T10:47:18Z

← Older revision		Revision as of 11:47, 26 June 2015
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	A good siting process would factor in both community preferences (needs) and technical suitability to ensure that the borehole was both accessible and productive. It is difficult to ascertain the technical details of the siting process from community discussions and unfortunately it was not possible to seek out the relevant experts in the time available. In all cases a survey of some kind was undertaken, but it was not always clear how extensive these surveys were or what kind of equipment was used. Some communities were entirely absent from the survey process (e.g. A5, A8, K10), most were involved to some extent, whilst a few clearly played a very active role in proposing and shortlisting potential sites (such as A1 and K1). In many cases, based on the data available, it was difficult to determine the rationale behind the selection of a particular site. In K5, for instance, the community were not involved in site selection and also claimed that the drillers did not construct the water point at the location selected by the surveyors.		A good siting process would factor in both community preferences (needs) and technical suitability to ensure that the borehole was both accessible and productive. It is difficult to ascertain the technical details of the siting process from community discussions and unfortunately it was not possible to seek out the relevant experts in the time available. In all cases a survey of some kind was undertaken, but it was not always clear how extensive these surveys were or what kind of equipment was used. Some communities were entirely absent from the survey process (e.g. A5, A8, K10), most were involved to some extent, whilst a few clearly played a very active role in proposing and shortlisting potential sites (such as A1 and K1). In many cases, based on the data available, it was difficult to determine the rationale behind the selection of a particular site. In K5, for instance, the community were not involved in site selection and also claimed that the drillers did not construct the water point at the location selected by the surveyors.

	[[Image:~~OR15019_fig10~~.jpg\|thumb\|center\|~~300px~~\| '''Figure 10''' Dominant symptoms of water point failure.]]		[[Image:15019_fig10.jpg\|thumb\|center\|400px\| '''Figure 10''' Dominant symptoms of water point failure.]]

	[[Image:~~OR15019_fig11~~.jpg\|thumb\|center\|~~300px~~\| '''Figure 10''' Presence of a WUC for the water point in the communities.]]		[[Image:15019_fig11.jpg\|thumb\|center\|400px\| '''Figure 10''' Presence of a WUC for the water point in the communities.]]

	~~[Image]]:filename\|thumb\|widthpx\| ]]~~The community survey data indicated that water point construction was rarely supervised properly, if at all. Ideally a technical expert such as a hydrogeologist or engineer would be present throughout the process. At two sites a non‐technical expert from the local NGO was supervising throughout. In six other cases there were spot checks during construction by the DWO or NGO. Communities felt unable to judge quality of construction work or materials used and were generally poorly informed about the siting and drilling process.		The community survey data indicated that water point construction was rarely supervised properly, if at all. Ideally a technical expert such as a hydrogeologist or engineer would be present throughout the process. At two sites a non‐technical expert from the local NGO was supervising throughout. In six other cases there were spot checks during construction by the DWO or NGO. Communities felt unable to judge quality of construction work or materials used and were generally poorly informed about the siting and drilling process.

	== Water quality and yield ==		== Water quality and yield ==
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	Typical roles on the WUC included: chairman, secretary, caretaker, treasurer, and sometimes health or sanitation and hygiene educator. Caretakers were responsible for day‐to‐day management of the water point, including enforcement of by‐laws. Some WUCs met on a regular basis, others only when problems arose. In a couple of cases only certain members of the committee were active, usually the caretaker or chairman. WUCs became inactive when the water point was non‐functional for a significant period of time, particularly where the problem was deemed beyond the Hand Pump Mechanics’ (HPM) capacity to repair. Where communities have been affected by civil unrest, some of the older water points had been left unused (and therefore unmanaged) for several years. With the exception of four cases, communities generally appeared to be satisfied with their WUCs.		Typical roles on the WUC included: chairman, secretary, caretaker, treasurer, and sometimes health or sanitation and hygiene educator. Caretakers were responsible for day‐to‐day management of the water point, including enforcement of by‐laws. Some WUCs met on a regular basis, others only when problems arose. In a couple of cases only certain members of the committee were active, usually the caretaker or chairman. WUCs became inactive when the water point was non‐functional for a significant period of time, particularly where the problem was deemed beyond the Hand Pump Mechanics’ (HPM) capacity to repair. Where communities have been affected by civil unrest, some of the older water points had been left unused (and therefore unmanaged) for several years. With the exception of four cases, communities generally appeared to be satisfied with their WUCs.

	[[Image:~~OR15019_fig12~~.jpg\|thumb\|center\|~~300px~~\| '''Figure 12''' Was training received by WUCs?.]]		[[Image:15019_fig12.jpg\|thumb\|center\|400px\| '''Figure 12''' Was training received by WUCs?.]]

	Six of the WUCs had received 2‐3 days training by the implementing agency or, in one case, another NGO. Another three claimed to have received ‘some’ training, however half of the WUCs received no training at all (Figure 12). Training usually included subjects such as looking after the water point (e.g. fencing, using the pump properly), related sanitation and hygiene issues (e.g. using clean jerry cans, keeping animals away, location of latrines), and record and accounts keeping. Topics that were not covered were preventative maintenance and minor repairs (HPM’s are expected to provide this service), information regarding the potential costs of repairs, or advice on how much money to collect from users. None of the WUCs reported follow‐up training or other capacity building efforts.		Six of the WUCs had received 2‐3 days training by the implementing agency or, in one case, another NGO. Another three claimed to have received ‘some’ training, however half of the WUCs received no training at all (Figure 12). Training usually included subjects such as looking after the water point (e.g. fencing, using the pump properly), related sanitation and hygiene issues (e.g. using clean jerry cans, keeping animals away, location of latrines), and record and accounts keeping. Topics that were not covered were preventative maintenance and minor repairs (HPM’s are expected to provide this service), information regarding the potential costs of repairs, or advice on how much money to collect from users. None of the WUCs reported follow‐up training or other capacity building efforts.
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	==Technical investigations==		==Technical investigations==
	[[Image:~~OR15019_fig12.jpg\|thumb\|center\|300px\| ]]~~		[[Image:15019_fig004.jpg\|thumb\|center\|300px\| Bailer (left) and pumping tests (right) being carried out in Amuria District.]]

	~~[[Image:OR15019_fig12~~.jpg\|thumb\|center\|300px\| Bailer (~~top~~) and pumping tests (~~bottom~~) being carried out in Amuria District.]]

	The main technical findings of the fieldwork are summarised below.		The main technical findings of the fieldwork are summarised below.

Dbk at 08:07, 25 June 2015

2015-06-25T08:07:55Z

← Older revision		Revision as of 09:07, 25 June 2015
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	Laboratory analyses of the groundwater samples taken indicate relatively high organic carbon content (material derived from decaying vegetation, bacterial growth, and metabolic activities of living organisms or chemicals), with average NPOC (Non‐Purgeable Organic Carbon – commonly referred to as total organic carbon (TOC)) measured as 0.8 mg/l (range 0.47 to 2.37 mg/l), and high dissolved iron (Fe) content – average total Fe 600 µg/l (over half of the samples had Fe in excess of 200 µg/l, with three >1000 µg/l). The high iron content in abstracted waters is supported by corrosion and staining of the pump components and by observation of significant orange staining at all the boreholes investigated in the CCTV surveys. This is most likely attributable to the high iron content of the waters, but may also be contributed to by ingress of soil particles into the boreholes which have screened intervals in the regolith (Figure 14). Elevated concentrations of zinc (five sites having Zn over 200 µg/l) are indicative of corrosion processes having taken place. Manganese concentrations were <200 µg/l in nearly all the waters. Full laboratory results are shown in Appendix 4.		Laboratory analyses of the groundwater samples taken indicate relatively high organic carbon content (material derived from decaying vegetation, bacterial growth, and metabolic activities of living organisms or chemicals), with average NPOC (Non‐Purgeable Organic Carbon – commonly referred to as total organic carbon (TOC)) measured as 0.8 mg/l (range 0.47 to 2.37 mg/l), and high dissolved iron (Fe) content – average total Fe 600 µg/l (over half of the samples had Fe in excess of 200 µg/l, with three >1000 µg/l). The high iron content in abstracted waters is supported by corrosion and staining of the pump components and by observation of significant orange staining at all the boreholes investigated in the CCTV surveys. This is most likely attributable to the high iron content of the waters, but may also be contributed to by ingress of soil particles into the boreholes which have screened intervals in the regolith (Figure 14). Elevated concentrations of zinc (five sites having Zn over 200 µg/l) are indicative of corrosion processes having taken place. Manganese concentrations were <200 µg/l in nearly all the waters. Full laboratory results are shown in Appendix 4.
			<center>
	{\| class="wikitable"		{\| class="wikitable"
	\|+ Table 6 Well head groundwater chemistry measurements taken at the water point after the borehole had been purged. A16 was the only water point to have a clear aesthetic water appearance. (Abbreviations: SEC – Specific Electrical Conductance; Eh – redox potential, measured in millivolts; DO – dissolved oxygen; HCO''''3 ''''‐ bicarbonate; RWL‐ rest water level in metres below ground level).		\|+ Table 6 Well head groundwater chemistry measurements taken at the water point after the borehole had been purged. A16 was the only water point to have a clear aesthetic water appearance. (Abbreviations: SEC – Specific Electrical Conductance; Eh – redox potential, measured in millivolts; DO – dissolved oxygen; HCO''''3 ''''‐ bicarbonate; RWL‐ rest water level in metres below ground level).
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	\| 3.035		\| 3.035
	\|}		\|}
			</center>
	''Groundwater residence time indicators''<br>The analysis of dissolved anthropogenic gas concentrations (CFC, SF6) indicates a difference in the ages of the waters abstracted from the water points. Half of the water points sampled are indicated to yield groundwater with a residence time less than 10 years old, whilst the other half of the water points yield groundwater which has a residence time of over 30 years old – Figure 15. This difference is most likely attributable to the difference in the borehole designs of the water points. Four out of the five samples which are indicated to have a residence time less than 10 years were from boreholes which contained a screened section within the shallow regolith. Inflows of shallow groundwater, which will be recharged from recent seasonal rainfall, will therefore inflow the borehole. These inflows were observed from the CCTVs in most cases in these boreholes.		''Groundwater residence time indicators''<br>The analysis of dissolved anthropogenic gas concentrations (CFC, SF6) indicates a difference in the ages of the waters abstracted from the water points. Half of the water points sampled are indicated to yield groundwater with a residence time less than 10 years old, whilst the other half of the water points yield groundwater which has a residence time of over 30 years old – Figure 15. This difference is most likely attributable to the difference in the borehole designs of the water points. Four out of the five samples which are indicated to have a residence time less than 10 years were from boreholes which contained a screened section within the shallow regolith. Inflows of shallow groundwater, which will be recharged from recent seasonal rainfall, will therefore inflow the borehole. These inflows were observed from the CCTVs in most cases in these boreholes.