‘Truth or Consequences’ for the practicing hydrologist: on scientific certainty and ethics

Correspondence to: D. I. Siegel, Professor of Earth Sciences, Syracuse University, Syracuse, NY 13244, USA. E-mail: disiegel@mailbox.syr.edu A number of years ago there was a famous TV game show in the United States called ‘Truth or Consequences.’ In this show, contestants who told the ‘truth’ were rewarded with money and those who did not suffered the ‘consequences’ of receiving nothing. I would hope that for all hydrologists, not being scientifically truthful is anathema, insulting to even consider. But hydrologists in the consulting workplace have to legitimately wrestle now and then with what constitutes scientific ‘truth,’ balancing what is right for science and the need to satisfy paying clients. The contrast between how science is done in academia and consulting can be striking. Tenured university faculty who delay research publication because of uncertainty may not get quick grant renewals, but they don’t lose their jobs. Practicing hydrologists who hold up reports for clients for the same reasons can lose contracts as well as their jobs. So I ask, how many academic programs teach anything about how hydrology is really done in the workplace, namely, how to critically evaluate scant data, sometimes poor data, to arrive at a defendable ‘best professional judgement.’ Getting to scientific ‘truth’ costs money and a dilemma always in practice is how much does a client wants to pay for the truth he gets. Making these kinds of hydrologic decisions, ‘best professional judgements,’ is particularly important in environmental litigation, common in the United States. An excellent demonstration of how hydrology can be done in practice is the book A Civil Action (Harr, 1995) about the Woburn TCE contamination case. Hydrologists reading this book should be appalled by the unsound hydrogeologic conceptualizations suggested by some of the hydrologic consultants, as well as by the distortion of the sound science in the legal arena. Mistakes and misrepresentation of hydrology and geochemistry are common in practice. I consult as well as teach, and here are some classic ‘boners’ I have seen in and out of the courtroom (see if your students understand why these are boners): ‘Chemicals diffuse through unfractured saturated clay at a rate of feet per day; You can pump a well in clay or competent till at a rate of 20 l/min 3⁄45 gpm for two days and observe drawdown in monitoring wells 30 m 3⁄4100 ft away; It is plausible that a river can inseep and outseep to groundwater in 100-m long alternating segments along a kilometer reach; The dispersivity of an aquifer is equal to flow-path lengths up to scales of tens of meters.’ I have even heard a presentation by consultants on how to purposefully use graphics in hydrologic computer models to enhance scientific positions that are not clearly supported by the data!