Table 3.

Assessment of hazardous events at catchments by seven raters.

Hazard	Hazardous event	Likelihood avg (SD)	Severity avg (SD)	Risk level avg (SD)
Chemical	High level of dissolved salts in water	4.11 (0.65)	3.41 (0.58)	14.04 (3.26) (high risk)
Microbial and chemical	Excessive algal formations in water storage tanks	2.93 (0.52)	3.40 (0.66)	10.15 (3.19) (high risk)
Microbial	Sewage collection within 200 m of the borehole	2.38 (0.73)	2.97 (0.79)	7.48 (3.76) (medium risk)
Microbial	Water leakage between water well and water storage tank	2.54 (0.63)	2.82 (0.63)	7.41 (3.21) (medium risk)
Microbial	The leaking water forms stagnant ponding within 10 m of the borehole	2.49 (0.74)	2.69 (0.75)	7.09 (3.50) (medium risk)
Chemical and microbial	Spilled water drainage channels are absent or cracked or unclean	2.40 (0.70)	2.67 (0.73)	6.77 (3.44) (medium risk)
Microbial	Human, animals, or birds excreta on the ground within 10 m of the borehole	2.25 (0.66)	2.80 (0.75)	6.62 (3.29) (medium risk)
Microbial	The fence of the water well is inadequate to prevent the entry of animals	2.36 (0.64)	2.68 (0.66)	6.61 (3.10) (medium risk)
Chemical	Accidental spillage of diesel or other chemicals within 100 m of the borehole	2.33 (0.65)	2.68 (0.76)	6.60 (3.30) (medium risk)
Chemical, microbial, and physical	The cement cap of a borehole is absent, cracked or unclean	2.33 (0.66)	2.57 (0.69)	6.29 (2.99) (medium risk)
Chemical and microbial	The pump house at the point of attachment to the borehole base is loose	2.28 (0.72)	2.53 (0.74)	6.16 (3.15) (medium risk)
Chemical and microbial	Stockbreeding, agricultural activities within 50 m of the borehole	2.19 (0.60)	2.60 (0.69)	5.96 (2.71) (low risk)
Microbial	Rainstorms or floods affect the borehole area	2.20 (0.76)	2.38 (0.80)	5.72 (3.41) (low risk)
Chemical, microbial, and physical	Waste disposal site or landfill within 300 m of the borehole	2.07 (0.66)	2.29 (0.76)	5.15 (2.99) (low risk)

Risk level = likelihood ∗ Severity.