An evaluation of the relative importance of the effects of climate change and groundwater extraction on seawater intrusion in coastal aquifers in Atlantic Canada

2013 ◽  
Vol 22 (3) ◽  
pp. 609-623 ◽  
Author(s):  
N. R. Green ◽  
K. T. B. MacQuarrie
Keyword(s):  
Climate Change ◽  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Atlantic Canada ◽  
Relative Importance ◽  
Groundwater Extraction

scholarly journals Analysis of Saline Intrusion into a Coastal Aquifer: A Case History of Legacy Issues and Challenges to Water Security

2018 ◽  
Vol 8 (2) ◽  
pp. 16 ◽  
Author(s):  
Nara Somaratne ◽  
Glyn Ashman
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Coastal Aquifer ◽  
Discharge Rate ◽  
Analytical Models ◽  
Original Position ◽  
Saline Intrusion ◽  
Groundwater Extraction ◽  
Supply Source ◽  
Freshwater Lenses

Coastal aquifers are subject to seawater intrusion. Therefore, managing freshwater aquifers in coastal areas remain challenging. At present, determining safe yields from the coastal aquifers to prevent seawater intrusion is primarily based on the use of numerical simulation-optimization models or by the use of analytical models based on the Ghyben-Herzberg principle. This study examines the cause and effects of seawater intrusion into a coastal aquifer, Lincoln Basin in southern Eyre Peninsula, South Australia and shows that application of simple techniques would have prevented seawater intrusion. Three freshwater lenses, Lincoln A, B, and C of the Lincoln Basin, located about 13 km southwest of Port Lincoln township, have been developed as a town water supply source in 1960. The capacity of the basin has been assessed by three long-term pumping tests. Based on pump tests results, three areas were developed to supply 2×106 m3 per year distributed across three lenses as lens A : four wells to supply 0.84×106 m3, lens B: four wells to supply 0.5×106 m3 and lens C: four wells to supply 0.66 ×106 m3. Neither recharge to the freshwater lenses nor a water balance had been assessed, and a precautionary approach to groundwater extraction was not followed. The apparent driver for managing the basin was demand for the township. In this study, we assessed the recharge using two methods; water-table fluctuation (WTF) and the conventional chloride mass balance (CMB) method. Total recharge to the freshwater lenses is estimated at 1.6×106 m3 per year which is less than the average annual groundwater extraction from the basin during the 1961-1977 periods (average 2.14×106 m3). As a result mining of the groundwater storage has occurred in the basin leading to saline intrusion, upconing and lateral flow of brackish water into wellfield areas. The total volume extracted from the basin was 35×106 m3, which exceeded the average recharge over the 15 year period, 24×106 m3. Using analytical methods, the seawater/freshwater interface movement from its original position was estimated to be 35 m in lens A, 337 m in lens B and 188 m in lens C. For each pumping well at maximum discharge rate, the transient interface location directly underneath the well was calculated. This results in interface rises under pumping wells in lens A of 3.8 m, lens B of 0.5 m, and in lens C about 0.7 m. According to the risk-based groundwater allocation method, maximum extraction would have been as a proportion of 25% of the annual recharge. Thus, maximum annual abstraction limits for lens A, B and C would have been 210×103 m3, 72×103 m3 and 130×103 m3, totaling 412×103 m3.

scholarly journals Groundwater resources at salinisation risk: effects of climate and utilisation changes in the case of Apulian coastal aquifers (Southeastern Italy)

2019 ◽  
Author(s):  
Domenico Casarano ◽  
Vittoria Dragone ◽  
Maurizio Polemio
Keyword(s):  
Climate Change ◽  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Groundwater Resources ◽  
Rainfall Trend ◽  
Groundwater Availability ◽  
Risk Effects ◽  
Periodic Data ◽  
Relevant Explanation ◽  
Negative Characteristic

Seawater intrusion is the main cause of groundwater salinisation in Italy. The largest coastal aquifers, highly vulnerable to salinisation, are in Apulia. For these aquifers, main changes in terms of climate change and utilisation are discussed together with piezometric trends, as the latter are relevant triggering factors for upconing and lateral seawater intrusion. For this purpose, time series from 1921 to 2016 concerning climate (rainfall and temperature), from 1965 to 2016 concerning groundwater availability (piezometric values), and recent periodic data on potable utilisation are discussed. Climate and groundwater availability trends at 2016 are compared with trends previously assessed, using the same dataset (1921-2001 for rainfall and temperature). The negative characteristic of rainfall 1921-2001 trend improved in the next years up to disappear in the assessment of rainfall 1921-2016 trend. Notwithstanding the improving of rainfall trend and the reduction of groundwater utilisation, both observed at 2016, the improvement of piezometric trends at 2016 is not enough to remove a prevailing decreasing trend, previously observed. The increases of temperature and effective evapotranspiration should be considered a relevant explanation of groundwater availability reduction. The consequence of these results should be quickly considered in the management of groundwater resources.

Impact of sea level rise and over-pumping on seawater intrusion in coastal aquifers

2011 ◽  
Vol 2 (1) ◽  
pp. 19-28 ◽  
Author(s):  
H. F. Abd-Elhamid ◽  
A. A. Javadi
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Transition Zone ◽  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Element Model ◽  
Combined Effects ◽  
Sea Levels ◽  
The Individual

Climate change, sea level rise, over-pumping and saltwater intrusion present some of the future challenges of water resources management in coastal areas. Over-abstraction is considered one of the main causes of seawater intrusion and the rise in sea levels accelerates the intrusion. With the combined impact of sea level rise and over-pumping the problem becomes exacerbated and requires urgent solutions. Previous studies have mainly focused on the study of impact of sea level rise or over-abstraction on seawater intrusion separately and their combined effects have not been studied in the literature. This paper presents application of a coupled transient density-dependent finite element model to simulate seawater intrusion in coastal aquifers and investigates the individual and combined effects of likely sea level rise and over-pumping on seawater intrusion. Three scenarios are considered: rise in sea levels due to climate change, decline in groundwater table due to over-pumping and combination of sea level rise and over-pumping. The results show that, in the case study considered in this paper, the rise in the sea level moved the transition zone inland by about 5%. However, the combination of sea level rise and over-pumping resulted in further inland movement of the transition zone (about 8%). The amount of intrusion greatly depends on the depth, size and properties of the aquifer. While the intrusion is a few metres in a small aquifer, it could be several kilometres in a large aquifer.

Analyzing competing land use policy objectives under climate change – a regional case study from Austria

2021 ◽  
Author(s):  
Katrin Karner ◽  
Hermine Mitter ◽  
Erwin Schmid
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Organic Carbon ◽  
Nitrate Leaching ◽  
Climate Scenario ◽  
Groundwater Extraction ◽  
Climate Scenarios ◽  
Abandoned Land ◽  
Policy Objectives ◽  
Net Benefits

<p>In the semi-arid Seewinkel region in Austria, competing demands exist for land and water such as from agriculture, nature protection, tourism and settlements. In addition, water quality problems are prevalent due to nitrate leaching in groundwater in the region. Climate change likely will amplify existing resource demands and environmental impacts, imposing considerable challenges for adapting and regulating agriculture in the Seewinkel. Hence, compromises between competing policy objectives are needed. <br>The aim of this presentation is to assess efficient land and water management strategies considering several economic and agro-ecological policy objectives in the Seewinkel region in context of climate scenarios. A multi-objective optimization experiment was performed with an integrated modelling framework to compute agro-economic-ecological Pareto frontiers. The frontiers combine levels of (i) net benefits from agricultural production, (ii) groundwater extraction for agricultural irrigation, (iii) nitrate leaching from agricultural production, and (iv) topsoil organic carbon stocks. 30 stochastic realizations of three climate scenarios are considered for a future period of 31 years: WET, SIMILAR and DRY, which mainly differ regarding annual precipitation volumes. <br>Model results show that a 1% (20%) reduction of agricultural net benefits can lower groundwater extraction by 11-83% (61-100%) and nitrate leaching by 18-19% (49-53%) as well as increase topsoil organic carbon sequestration by 1% (5%) depending on the climate scenario. However, substantial changes in land use and management would be required. For instance, less groundwater extraction by 11-83% requires a 6-21% reduction of irrigated cropland, a 21-33% reduction of highly fertilized cropland, a 10-24% increase of grassland, and a 23-52% increase of abandoned land depending on the climate scenario. Less nitrate leaching by 18-19% (or higher topsoil organic carbon stocks by 1%) require that highly fertilized cropland decreases by 9-13% (4-7%), abandoned land increases by 5-9% (19-49%) and grassland either declines by 3% (14%) or increases by up to 5% (32%) depending on the climate scenario. In general, the share of grassland increases in the wetter climate scenario.<br>Overall, the analysis reveals that especially groundwater extraction and nitrate leaching can be reduced substantially for fairly small reduction in agricultural net benefits in all climate scenarios. 50% of maximum modelled improvements of agro-ecological objectives can be already achieved at 1-15% reductions of agricultural net benefit depending on climate scenarios. Thus, respective land use policies would allow considerable improvements of the agro-ecological performance at relatively low costs. However, improving the agro-ecological performance beyond a particular level can quickly lead to high reductions of agricultural net benefits, as depicted by the non-linear form of the Pareto frontiers. This is mainly related to large declines of cropland and increases in grassland or abandoned land. Furthermore, the results indicate that water management policies are less costly than climate change mitigation policies, at least in the Seewinkel region.</p>

scholarly journals The importance of hydrological uncertainty assessment methods in climate change impact studies

2014 ◽  
Vol 18 (8) ◽  
pp. 3301-3317 ◽  
Author(s):  
M. Honti ◽  
A. Scheidegger ◽  
C. Stamm
Keyword(s):  
Climate Change ◽  
Climate Change Impact ◽  
Hydrological Model ◽  
Uncertainty Assessment ◽  
Assessment Method ◽  
Calibration Data ◽  
Relative Importance ◽  
Impact Studies ◽  
Uncertainty Sources ◽  
Change Impact

Abstract. Climate change impact assessments have become more and more popular in hydrology since the middle 1980s with a recent boost after the publication of the IPCC AR4 report. From hundreds of impact studies a quasi-standard methodology has emerged, to a large extent shaped by the growing public demand for predicting how water resources management or flood protection should change in the coming decades. The "standard" workflow relies on a model cascade from global circulation model (GCM) predictions for selected IPCC scenarios to future catchment hydrology. Uncertainty is present at each level and propagates through the model cascade. There is an emerging consensus between many studies on the relative importance of the different uncertainty sources. The prevailing perception is that GCM uncertainty dominates hydrological impact studies. Our hypothesis was that the relative importance of climatic and hydrologic uncertainty is (among other factors) heavily influenced by the uncertainty assessment method. To test this we carried out a climate change impact assessment and estimated the relative importance of the uncertainty sources. The study was performed on two small catchments in the Swiss Plateau with a lumped conceptual rainfall runoff model. In the climatic part we applied the standard ensemble approach to quantify uncertainty but in hydrology we used formal Bayesian uncertainty assessment with two different likelihood functions. One was a time series error model that was able to deal with the complicated statistical properties of hydrological model residuals. The second was an approximate likelihood function for the flow quantiles. The results showed that the expected climatic impact on flow quantiles was small compared to prediction uncertainty. The choice of uncertainty assessment method actually determined what sources of uncertainty could be identified at all. This demonstrated that one could arrive at rather different conclusions about the causes behind predictive uncertainty for the same hydrological model and calibration data when considering different objective functions for calibration.

scholarly journals Simulation of seawater intrusion in coastal aquifers: Some typical responses

Sadhana ◽  
2001 ◽  
Vol 26 (4) ◽  
pp. 317-352 ◽  
Author(s):  
Amlan Das ◽  
Bithin Datta
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifers

Seawater intrusion into coastal aquifers

2008 ◽  
Vol 35 (3) ◽  
pp. 274-286 ◽  
Author(s):  
M. G. Khublaryan ◽  
A. P. Frolov ◽  
I. O. Yushmanov
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifers
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