Choosing a Site for a Rural Clinic: Water, Flood Risk and Access
A sub-district council in eastern Botswana must choose one of three sites for a clinic serving four villages with a combined population of 6,400. Site A lies on flat black-cotton clay beside a gravel road that is graded twice a year; it is 3 km from a seasonal river that holds pools until August. Site B sits on a gentle slope below a granite outcrop; the tarred highway is 8 km away along a graded track, and trial drilling found bedrock at 6 m with a borehole yield of 0.8 litres per second. Site C is on deep sand 1.5 km from the highway, but its access track crosses a broad, shallow valley that floods for two to three weeks in most rainy seasons; the water table there is 45 m deep. Rainfall is about 450 mm a year, falling almost entirely between November and March, and daily maximum temperatures exceed 32 °C from September to March. The council's budget covers one borehole, one access road and one small waste-water soakaway.
1. Using named criteria, decide which site the council should choose. Justify the order in which you rank the criteria, and explain why one rejected site is weaker than the other.
Read the worked answer
Criteria and ranking
- Year-round water security – a clinic cannot function without water, and the budget allows only one borehole or one river connection, so this is a fixed constraint, not a reversible one.
- Freedom from flooding and good drainage – a flooded or waterlogged site cannot be fixed by spending; it damages foundations and interrupts services every rainy season.
- All-weather access – important, but a track can be upgraded, and the budget includes one access road, so this is a correctable weakness.
- Ground conditions and construction cost – affects price, not feasibility.
- Room for expansion and distance to users – relevant but cannot override 1–3.
Criteria 1 and 2 come first because they are permanent physical limits; criterion 3 is ranked below them precisely because money can remove it.
Applying the criteria
- Site A: water is nearby but seasonal, and flat clay drains badly, so the site is exposed to both late-dry-season water shortage and waterlogging. Two serious permanent weaknesses.
- Site C: near the highway and on well-drained sand, but the access valley floods for two to three weeks, and a 45 m water table makes the single permitted borehole expensive and its yield uncertain.
- Site B: the slope sheds water, there is no flood risk, bedrock at 6 m gives a reliable borehole, and 0.8 l/s is about 69 m³ a day - several times a small clinic's needs of roughly 15–25 m³ a day.
Decision: Site B, conditional on upgrading the 8 km track and confirming water quality. Its only real weakness is correctable within the budget, while the weaknesses of A and C are not.
2. A councillor argues that Site A is better because the river gives the clinic free water. Evaluate this argument.
Read the worked answer
The argument treats 'water present' as equal to 'water supply', which is the error the examiner wants exposed.
- Seasonality: the river is seasonal. Pools survive to about August, so September to November - the hottest months, with maximum temperatures above 32 °C - is exactly when the source is least reliable. A clinic's demand is constant all year.
- Quality: standing pools in a grazing area carry silt, animal waste and possibly upstream latrine contamination; the clinic would need treatment chemicals, storage and testing, all of which cost money and staff time.
- Site and flood hazard: the water lies on flat black-cotton clay. Reaching it means building on poorly drained ground that swells and shrinks, cracking foundations and soakaways, and the same flat ground raises flood and mosquito-breeding risk.
- Hidden costs: a pump, fuel, a rising main, a storage tank and a standby supply for the dry season mean the water is not free; it is merely unpriced at the source.
Balanced conclusion: the river is a genuine advantage as a secondary source for washing and construction water, but it cannot be the clinic's main supply. The councillor is right about cost and wrong about reliability, and reliability is the criterion that matters most for a health facility.
3. Identify two further pieces of information the council should collect, and explain how each could change the decision.
Read the worked answer
1. Groundwater quality at Sites B and C (salinity, fluoride, nitrate). Yield is not the same as usable water. Parts of eastern Botswana have fluoride and salinity problems, and a 6 m granite borehole may give water that is plentiful but undrinkable without treatment. If Site B's water exceeded drinking guidelines, B would lose its main advantage and the ranking would shift toward a piped or treated supply - possibly making Site C or a river-plus-treatment option preferable despite higher cost.
2. A mapped flood extent and duration for the Site C valley, plus travel times from each village. If the flooded track is passable on foot or by tractor, the two-to-three-week cut-off may be a manageable inconvenience rather than a disqualifier, and C's proximity to the highway would become decisive. Conversely, if floodwater stands for six weeks, C is confirmed as unsafe. Travel-time data would also test whether B's 8 km detour actually delays emergency referrals, or whether the upgraded track makes the difference negligible.
Other acceptable answers: confirmed land ownership and planning permission; a firm quotation for upgrading the 8 km track; projected population growth in the four villages; an estimate of the water table depth and success rate for boreholes in granite versus sand. In each case the answer must state what would change, not just what would be collected.