Animal Waste, Water Quality and Human Health

440Animal Waste, Water Quality and Human Healthof the stated preference or revealed preference valuation approachesoutlined above.Benefits transfer is still in its infancy, in part because for many environmentalpolicy issues only a limited number of high quality valuation studies have beencompleted. It has, however, the potential to become a significant and usefulestimation approach. The most important reason for using previous researchresults in new policy contexts is that it saves a lot of time and resources.Applying previous research findings to similar decision situations is an attractivealternative to expensive and time-consuming original research to informdecision-making. Some previous valuation studies relating to recreational waterquality that may be used for benefits transfer are discussed below.12.3.5 Recreational water quality valuation studiesA considerable body of literature of an applied nature has evolved over thepast two decades, relevant to the valuation of the benefits of interventionsconcerning recreational water quality. Most of the studies obtain valuemeasures by utilising some form of travel cost/random utility model,contingent ranking exercise or some form of contingent valuation methodsurvey. Table 12.1 summarises various studies that have been undertakeninternationally on valuing recreational water quality improvements. Derivedestimates have been converted to common values in pounds sterling (UK£)at 2006 prices. It is immediately clear that, although few of the studies relatedirectly to animal waste, the application of the various “revealed preference”and “stated preference” studies to recreational water quality more generally iswell established.Although all estimates are converted into common terms, the range of meanWTP estimates found is quite wide. This can be partly explained by differencesin the valuation methods used as these yield theoretically different estimates(Bateman & Jones 2003), but is also a reflection of the variety of scales or“scope” of water quality changes being considered in different studies.Furthermore, there may also be differences across the studies in the range ofbenefits examined. For example, while some studies only consider healthbenefits, others also consider ecological, aesthetic, recreational and amenityimprovements. While these differences in study design and remit naturally yielda range of value estimates, some consistent findings emerge, including, mostclearly, that individuals hold significant and positive values for improvements inrecreational water quality. These values imply substantial aggregate benefitsacross populations as a whole.