3. Holding, S; Allen, DM; Foster, S; Hsieh, A; Larocque, I; Klassen, J; Van Pelt, SC.Groundwater vulnerability on small islands.Nat. Clim. Chang., 2016, 6: 1100-+ Groundwater vulnerability on small islands
The majority of naturally occurring freshwater on small islands is groundwater, which is primarily recharged by precipitation(1). Recharge rates are therefore likely to be impacted by climate change(2). Freshwater resources on small islands are particularly vulnerable to climate change because they are limited in size and easily compromised(3-5). Here we have compiled available aquifer system characteristics and water-use data for 43 small island developing states distributed worldwide, based on local expert knowledge, publications and regional data sets. Current vulnerability was assessed by evaluating the recharge volume per capita. For future vulnerability, climate change projections were used to estimate changes in aquifer recharge. We find that 44% of islands are in a state of water stress, and while recharge is projected to increase by as much as 117% on 12 islands situated in the western Pacific and Indian Ocean, recharge is projected to decrease by up to 58% on the remaining 31 islands. Of great concern is the lack of enacted groundwater protection legislation for many of the small island developing states identified as highly vulnerable to current and future conditions. Recharge indicators, shown alongside the state of legal groundwater protections, provide a global picture of groundwater supply vulnerability under current and future climate change conditions. DOI
2. Taylor, RG; Scanlon, B; Doll, P; Rodell, M; van Beek, R; Wada, Y; Longuevergne, L; Leblanc, M; Famiglietti, JS; Edmunds, M; Konikow, L; Green, TR; Chen, JY; Taniguchi, M; Bierkens, MFP; MacDonald, A; Fan, Y; Maxwell, RM; Yechieli, Y; Gurdak, JJ; Allen, DM; Shamsudduha, M; Hiscock, K; Yeh, PJF; Holman, I; Treidel, H.Ground water and climate change.Nat. Clim. Chang., 2013, 3: 322-329 Ground water and climate change
As the world's largest distributed store of fresh water, ground water plays a central part in sustaining ecosystems and enabling human adaptation to climate variability and change. The strategic importance of ground water for global water and food security will probably intensify under climate change as more frequent and intense climate extremes (droughts and floods) increase variability in precipitation, soil moisture and surface water. Here we critically review recent research assessing the impacts of climate on ground water through natural and human-induced processes as well as through groundwater-driven feedbacks on the climate system. Furthermore, we examine the possible opportunities and challenges of using and sustaining groundwater resources in climate adaptation strategies, and highlight the lack of groundwater observations, which, at present, limits our understanding of the dynamic relationship between ground water and climate. DOI
1. Chesnaux, R; Allen, DM; Graham, G.Assessment of the impact of nutrient management practices on nitrate contamination in the abbotsford-sumas aquifer.Environ. Sci. Technol., 2007, 41: 7229-7234 Assessment of the impact of nutrient management practices on nitrate contamination in the abbotsford-sumas aquifer
The impact of recent changes to nutrient management practices in raspberry fields on the loading and subsequent transport of nitrate through the vadose zone of the Abbotsford-Sumas aquifer is investigated numerically. Previous studies have shown that nitrate concentrations in the aquifer have remained relatively stable despite a shift in nutrient management practices. Using an estimate of net annual available nitrogen in fields that are fertilized using synthetic fertilizer, nitrate concentrations as a function of time and depth through the vadose zone are simulated from spring to late fall. Results indicate rapid leaching of nitrate owing to the permeable nature of the aquifer and suggest that nitrate loading to the water table may occur earlier than previously thought, possibly due to spring rains. For an average fertilizer application rate of 90 kg of N/ha, the simulated nitrate concentration on Oct 1 within the top I m of soil is 33 mg of N/kg, while the residual soil nitrate measured in late September was 37 mg of N/kg. Taking into account the effects of dilution within the saturated zone,the simulated peak nitrate concentration is similar to average observed peak concentrations in a shallow monitoring well. A solution is offered for estimating nitrate concentration at the water table as a function of the rate of synthetic fertilizer applied to raspberry fields. DOI PubMed
