Groundwater and Climate Change! Paper: 'A Synopsis of Climate Change Effects on Groundwater Recharge'

In the days before online journal access this is the kind of paper you'd die for (after reading it, of course). Online or not, there are few things I enjoy more than a good synopsis paper. Brian Smerdon of the Alberta Geological Survey focuses on six recent groundwater and climate change review papers and draws some conclusions. 

Smerdon, Brian D., 2017. A Synopsis of Climate Change Effects on Groundwater Recharge, J. Hydrology, v. 555 (December 2017), pp. 125-128. https://doi.org/10.1016/j.jhydrol.2017.09.047

Download Smerdon_Synopsis_CC_Effects_GW_Recharge

 Highlights

1) Uncertainty of distribution and trend in future precipitation remains the largest uncertainty for predicting recharge.

2) Ensemble results fit to a probability distribution offers an approach to communicate uncertainty.

3) Groundwater and recharge mechanisms should be incorporated within GCMs.

I like the one about using GCMs, especially a number of them, and the use of ensemble results fit to a probability distribution. Forty years ago (1978) I recall reading a series of papers in Water Resources Research by Peter S. Eagleson about expressing components of the hydrologic cycle in terms of probability density functions (PDFs) - derived distributions. His approach was an early global-scale approach to hydrology; The 7-part WRR series was entitled Climate, Soil and Vegetation. Blew me away! Thanks to Michael van der Valk for reminding me of the title of Eagleson's series. 

Blew me away!

Abstract

Six review articles published between 2011 and 2016 on groundwater and climate change are briefly summarized. This synopsis focuses on aspects related to predicting changes to groundwater recharge conditions, with several common conclusions between the review articles being noted. The uncertainty of distribution and trend in future precipitation from General Circulation Models (GCMs) results in vary- ing predictions of recharge, so much so that modelling studies are often not able to predict the magnitude and direction (increase or decrease) of future recharge conditions. Evolution of modelling approaches has led to the use of multiple GCMs and hydrologic models to create an envelope of future conditions that reflects the probability distribution. The choice of hydrologic model structure and complexity, and the choice of emissions scenario, has been investigated and somewhat resolved; however, recharge results remain sensitive to downscaling methods. To overcome uncertainty and provide practical use in water management, the research community indicates that modelling at a mesoscale, somewhere between watersheds and continents, is likely ideal. Improvements are also suggested for incorporating groundwa- ter processes within GCMs.

 Background

Groundwater recharge is the result of an intricate relationship between energy and moisture occurring in the critical zone between the atmosphere and subsurface. The recharge process governs downward fluid flux across the water table, and relates the climate, vegetation, and subsurface characteristics for a given area. Thus, an understanding of the recharge process, including rates, timing and location, is important for hydrogeological charac- terization and groundwater resource assessment. However, recharge is challenging to measure directly (Scanlon et al., 2002), leading to an inherent uncertainty when trying to develop aquifer budgets, investigate groundwater vulnerability and migration of nutrients, and determine the impact of changes in land cover and climate.

Global climate change – the alteration of long-term climate pat- terns – will have an impact on ecosystems, economies and commu- nities. The Intergovernmental Panel on Climate Change (IPCC) acknowledged that groundwater use will increase as a result of the declining availability of surface water and increased global water consumption (IPCC, 2007). Arguably, uncertainty of the recharge process will be compounded with uncertainty associated with predicting future climate scenarios. The IPCC Fourth Assess- ment Report identified a gap in the knowledge of the impact of cli- mate change on groundwater resources (Kundzewicz et al., 2007) that triggered new work on climate change and groundwater. The results of several studies emerged in peer-reviewed hydrologic journals beginning in about 2009, with scientific reviews on the topic published between 2011 and 2016. The paucity of groundwa- ter and climate change research drove a significant increase in publications following the IPCC Fourth Assessment Report.

The aim of this short paper is to provide a synopsis of recent review articles pertaining to groundwater and climate change, with a focus on predicting changes to recharge conditions. Six arti- cles are identified, which provide a comprehensive coverage of groundwater and climate change. Each of these articles has a thor- ough review of the science, processes and case studies related to climate change and groundwater recharge. This synopsis does not aim to replicate these excellent review articles, but rather to provide an overview and context for the Special Issue on Aquifers Recharge. The articles identified in this synopsis contain extensive reference lists on groundwater and climate change.

Enjoy!

"If individuals salvaging public water lost to encroaching phreatophytes were permittted to create new water rights where there is no new water, the price of saltcedar jungles would rise sharply. And we would expect to see a thriving, if clandestine, business in saltcedar seed and phreatophyte cultivation." -- Steve Reynolds, former NM State Engineer

Comments

[Michael.]

Thanks a lot, Michael! The kind of paper you wish you had written yourself...