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flood water were taken from a total of 19 locations in two catchments in Indore during four storms in August and September 1994. These were analysed for faecal coliforms (FC) using the MPN technique (Indian Standards Institution, 1982). All samples showed FC concentrations greater than 105/100 ml, 55 were greater than 106/100 ml, and in the heaviest flood, half the 18 samples were above 107/100 ml. These samples were not taken from combined drains themselves, but from the streets of two communities where flooding took place. |
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Water quality standards for bathing water and for agricultural reuse of wastewater provide a useful point of comparison, as they involve comparable types of human contact. While adults do not deliberately swim in minor floods, exposure still occurs during children's play and adult travel in the community. In addition, flood waters frequently enter lower-lying homes, spreading faecal contamination into the domestic environment. Besides the relatively short-lived bacterial contamination during flooding, it is also plausible that flooding contributes to Ascaris and other enteric worm infections through the spread of their eggs. |
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Until recently, European bathing water standards were set at 2000 FC/100 ml (Council of the European Communities, 1976); these have recently been tightened (although not without controversy) to 200 FC/100 ml. Water quality guidelines for agricultural reuse are set at 1000 FC/100 ml, largely to protect the health of consumers, but also to remain consistent with bathing water quality standards (Mara and Cairncross, 1989). By either standard, the concentrations measured in the flood waters of Indore catchments thus violated both bathing and reuse standards by three to four orders of magnitude. |
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In another part of the study, Stephens et al. (1994) used qualitative social science methods to investigate perceptions of flooding by members of four Indore communities. Some of their findings are of particular interest to engineers: |
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Flooding was ranked low in comparison to other risks and problems, such as improvements in job opportunities, provision of housing, mosquitoes and smelly backlanes. |
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