Comments on Uncertainty in Groundwater Governance in the Volcanic Canary Islands, Spain

Abstract

Abstract:The uncertainty associated with natural magnitudes and processes is conspicuous in water resources and groundwater evaluation. This uncertainty has an essential component and a part that can be reduced to some extent by increasing knowledge, improving monitoring coverage, continuous elaboration of data and accuracy and addressing the related economic and social aspects involved. Reducing uncertainty has a cost that may not be justified by the improvement that is obtainable, but that has to be known to make the right decisions. With this idea, this paper contributes general comments on the evaluation of groundwater resources in the semiarid Canary Islands and on some of the main sources of uncertainty, but a full treatment is not attempted, nor how to reduce it. Although the point of view is local, these comments may help to address similar situations on other islands where similar problems appear. A consequence of physical and hydrological uncertainty is that different hydrogeological and water resource studies and evaluations may yield different results. Understanding and coarsely evaluating uncertainty helps in reducing administrative OPEN ACCESSWater 2015, 7 2953 instability, poor decisions that may harm groundwater property rights, the rise of complaints and the sub-optimal use of the scarce water resources available in semiarid areas. Transparency and honesty are needed, but especially a clear understanding of what numbers mean and the uncertainty around them, to act soundly and avoid conflicting and damaging rigid attitudes. However, the different situations could condition that what may be good in a place, may not always be the case in other places.

Estimating Natural Recharge by Means of Chloride Mass Balance in a Volcanic Aquifer: Northeastern Gran Canaria (Canary Islands, Spain)

“…This difference is not surprising because it was not possible to calibrate the daily water balance in soil with water table fluctuations or discharge measurements as these data are not available, and will probably never be obtained. This shows how the recharge estimation is uncertain and different methods may yield non-coincident or overlapping results [38].…”

Water management strategies in hotels in arid regions: results and implications from a case study on Gran Canaria island (Spain)

“…Water quality. Custodio et al, (2015) commented that while some anxiety about water scarcity in the Canary Islands is appropriate, quality may be a bigger source of concern than quantity. Although local tap water meets basic Spanish health standards, it has high mineral content (lime), and the government does not recommend drinking it.…”

Sustainability of intensive groundwater development: experience in Spain

“…In some point, the cost of correcting and compensating epistemological mistakes is less than the cost of improving knowledge and implementing results. Uncertainty of the different terms combines and the resulting recharge error may exceed the recharge value, even if calculated at daily level (Custodio et al 2015). Environmental, economic, and social data and processes are also quite uncertain.…”