Category Archives: Rehabilitation of wells

Rehabilitation of hand-dug wells: diagnostic and technical solutions

rehabStarting from practical cases observed on the field, the idea was to break down different steps of a diagnostic of a well in order to setup a protocol and to help appropriate decision-making as regard technical solutions. Of course, the major question in the background remains the relevance to rehabilitate an existing well versus the construction of a new well. Indeed, in some cases, the rehabilitation may appear inappropriate because it is too costly as compared to a new construction, or too risky or because of a too low feasibility to restore the well in a correct state.

See protocol in the following link to Pratiques website icon_pdf

Questions for well rehab SL

Understanding one of the main causes of wells’ drying in Sierra Leone, through an analysis of a water table movements.


Season well (getting dry in dry season with water table movements)

Why hand-dug wells should only be dug in a specific period of the year, corresponding to low aquifer level?

From a technical point of view, hand-dug well drying is often due to the fact that the pumping system does not draw deeply enough or that the well itself has not been dug enough. This is typically the case of structures dug outside of the low water level period, so the bottom of the column dries up with the movement of the water table during the dry season.

An analysis of 29 consecutive months records, collected to measure the variations of the water table level in relation with the rainfall evolution, clearly illustrated the importance of timing the sinking of a well to correspond to low aquifer levels. icon_pdf

Water quality monitoring: protocol for tracking coliforms,_original.jpgColiform bacteria are a commonly used bacterial indicator of sanitary quality of foods and water. They can be found in the aquatic environment, in soil and on vegetation; they are universally present in large numbers in the faeces of warm-blooded animals, and their presence is used to indicate that other pathogenic organisms of fecal origin may be present.

Therefore, after a campaign of new water points construction or for rehabilitation, Inter Aide is doing water analysis to confirm that the water is safe for drinking and that the improved water point will prevent people to be affected by water related diseases. kits (such as DelAgua kits)[1]that allow simple and reliable measurements that can be done on site or in a local simple laboratory (clean dedicated room).

[1] Other devices than Del Agua kits can be used such as Potatest (Wagtech).


Picture of a Petri Dish culture with development of thermotolerant coliforms : what we want to avoid !

The following note in the link hereafter is the protocol Inter Aide is using to proceed to bacteriological tests. icon_pdf

Security rules for hand-dug wells constructions or rehabilitations

The document in link lists general guidelines and advises for ensuring security, both for workers and villagers, while hand dug well construction. icon_pdf

Jamal security

Jamal, who is also hand pump technician, is working as contractor for well construction. He’s always using equipments such as helmet and harness attached to a security rope fixed on top, to go inside wells.

A wide range of hand pumps’ types : one of the challenge for maintenance in Sierra Leone

A survey conducted from October to November 2011 in the 7 chiefdoms targeted by the program in the South Bombali District showed that among the 569 hand dug wells and 110 boreholes that have been identified, only 66% of them were functional. This park of hand pumps is also ageing and quite varied: India Mark 2 (71%), PB Mark 2 (12%), Kardia (7%), Afridev, etc.variety of hand pumpsIt is therefore difficult for the communities to have an easy access to spare parts when their pumps are broken as such variety of models of hand pumps scatters the demand and makes difficult establishing a sustainable suply chain at local level.

  • Indian Mark II

India markHand pump made in India: galvanized or stainless type. In Sierra Leone, this pump is available in most of the suppliers at a reasonable cost for stainless type (around 2.900.000 SLL) and offers a good quality for its price. A regular maintenance is compulsory to ensure the sustainability and avoid major breakdown. The installation process is also really important and has to be done properly (iron rods lengths, cylinder position from the bottom, hand pump stand straight…).

see maintenance guidelines.

  • Kardia

KardiaHand pump made in Germany: K65 and K2000 types. Kardia is one of the strongest pumps of the market but is really expensive compare to an Indian Mark 2 (around 12.000.000 SLL). Most of these pumps were installed during the relief period when the funds were highly available. The main problem is that spare parts are quite expensive and very difficult to find.

see maintenance guidelines.