I never did find out from the book what precisely constitutes a ‘small dam’, but in the Glossary, several of the characteristics of a large dam are given, so I suppose that anything that doesn’t meet those criteria might be one, or in other words, ‘none of the above’. Indeed, based on its content the book should perhaps be entitled ‘Small Reservoirs’ rather than ‘Small Dams’.

The book is 191 pages long (there is an eBook version in PDF), and is largely qualitative, although quantitative data are given in tables. There are few formulae, and they are mainly concerned with computing volumes, of the dams themselves and of reservoirs. The author practises in Australia, a country that, owing to its general aridity, has a need for many small dams to support farming, and this expertise comes over as one reads through the book. Chapters cover not only design and construction, but also planning, investigation, maintenance, documentation, ecology, water quality, legal and commercial aspects of these dams. The legal framework is Australian, and some of the charm of the book comes from its sheer parochialism; for example, an account of farming ‘yabbies’ in the reservoirs impounded by small dams.

This is not a book for the lover of advanced computer techniques, or of higher soil mechanics and suchlike. If the dam is small enough, one can get away with all sorts of ‘sins’ that would fail a larger edifice, and examples are given of homogeneous fill (no core) and pipes laid in the dam fill; for a balanced view across dams of all sizes, one probably needs to read the much thicker book by Fell et al. (2005), of which a second edition is now available.

In many countries, the metric system reigns supreme, and Lewis gives conversion factors in an Appendix, although the choice of factors presented is eclectic (e.g. feet per second to kilometres per day, but not to the more obvious metres per second), and although factors are given for flow rates in gallons per minute or even million gallons per day, as well as the traditional acre feet per day, gallons are left out when it comes to volumetric measurement, where you have acre feet or megalitres and lump it! Perhaps Lewis did not want us to confuse imperial gallons and US gallons. The use of ‘lb’ and ‘lbf’ is inconsistent.

It is possible to read through this volume in one sitting, and a geotechnical engineer or engineering geologist with a lot of experience will find themselves mostly nodding in agreement with the assertions made, occasionally thinking ‘actually, that is a sensible way to put it’, and then sometimes recoiling in horror at what would have happened in a large dam if some of the things that appear to work well in small dams were employed in the former. The comment that before designing a large dam one should consult an expert on small dams was surprising (Section 5.2.1, p. 82), but in this context I imagine that the ‘large dam’ is in the perspective of a farmer, not a dam engineer or geologist. I found a few things that I thought were notable omissions; for example, the effect of swimmers on water quality, or even the safety of swimmers: I’m confident that if I lived in the outback, I should regard my local small reservoir as a potential swimming pool, and as far as yabbies are concerned, I think I would be more concerned about Australia’s famously poisonous or hostile fauna than my lunch of barbecued yabbies.

• © 2014 The Geological Society of London