First, I welcome the constructive approach taken in these comments. However, Naim makes an important error in his first line in stating that this is ''essentially an irrigation paper''. The abstract of the paper includes the following: ''Based on the work of various previous writers, an analytical framework and associated terms are proposed to better serve the needs of technical specialists from all water-using sectors, policymakers and planners in achieving more productive use of water and tracing the implications of interventions on other uses and users.'' (emphasis added) So the objective here is not sector-specific, and this bears strongly on much of my response -in particular, to the issue of ''Effective Efficiency'' -but it is important at the outset to stress that a broader audience is targeted.
Naim states (his Para 2A -all subsequent comments are referenced according to his paragraph numbering):
''The paper puts Classical Efficiency into spotlight by making it clear through various evidences that it does not work and gives flawed recommendations. This is indeed true.''
With that agreed, much progress is already evident. Indeed, I only find substantive disagreement with the thrust of the original paper in two areas. Perhaps the presentation is less theoretical than an academic might prefer (hence the recommendation ''one needs to develop a sample population of evidences, make a hypothesis and test its significance by an appropriate statistical test'') but the paper is aimed at practitioners and draws on practical examples. If some research funder is willing to support the proposed research, then perhaps a suitable framework for testing the hypothesis can be formulated. I am already pleased that we agree, as stated above, that ''Classical Efficiency . . . does not work and gives flawed recommendations''.
The two substantive areas that are taken up in some detail by Naim are inadequate specification of basin efficiency, and failure properly to address the Effective Efficiency approach (I note that David Seckler and Andy Keller are acknowledged for their contributions to the note.) So first, basin efficiency: As I understand it, just as Classical Efficiency is the ratio of water used by the plant to water diverted, Basin Efficiency is the ratio of water consumed to total water available in the basin (which may be in terms of total precipitation plus transfers, or just runoff . . .). I have always thought the term meaningless because as with ALL uses of the term efficiency we have the implication that higher is better.
It is not. Based on this indicator the Aral sea basin would have an ''efficiency'' in excess of 100%, and is described (rightly) as in crisis. Indeed any basin where outflow is zero for the whole or important parts of the year is, at least, 100% ''efficient'' and most would agree that a decline in ''efficiency'' would be a very good thing. Are IRRIGATION AND DRAINAGE