Wastewater Use in Agriculture: Challenges in Assessing Costs and Benefits

Estimating the benefits and costs of planned or unplanned, ongoing or future, water reuse projects is not without challenges. In additional to the common difficulties of applying cost benefits analysis in agriculture or for justifying the use of reclaimed wastewater, the chapter tries to present some particular challenges with respect to the assessment of wastewater irrigation in the developing country context where treatment might be minimal or lacking and irrigation an informal activity along wastewater canals as well as natural streams. Challenges start with the term ‘wastewater’, and the comparison of crop yields and farm incomes under wastewater and freshwater irrigation and cumulate in the difficulties of assessing and costing likely health and environmental impacts. Bottlenecks related more often to the correct quantification of differences or impacts than their economic valuation.