Talk:Groundwater

Add effects of climate change on groundwater resources

Hi User:Jarble, I saw your note in to-dos ("Describe the effects of climate change on groundwater resources") and I agree it's a good task and I plan to tackle this in the coming week. Do you have any particular pointers in mind, e.g. also related Wikipedia articles where this is perhaps already included? I'll look at effects of climate change and effects of climate change on the water cycle. We'll have to make sure the same content is not repeated too much on several Wikipedia articles. EMsmile (talk) 13:36, 7 December 2022 (UTC)

@EMsmile: I updated the to-do list a while ago (in 2019); since then, an article about the effects of climate change on the water cycle has been written. This article describes some of the effects of climate change on groundwater resources. Jarble (talk) 17:49, 7 December 2022 (UTC)

OK, then I have now removed that item from the to do list. I'll do a bit more work to link better to that article. EMsmile (talk) 14:40, 12 December 2022 (UTC)

Removed content on management issues

I've removed this section on management issues because it was overly specific and not suitable for a high level overview article on groundwater. Also it was all relying on just one primary source. EMsmile (talk) 14:49, 19 January 2023 (UTC)

Management issues

Water management agencies, when calculating the "sustainable yield" of aquifer and river water, have often counted the same water twice, once in the aquifer, and once in its connected river. This problem, although understood for centuries, has persisted, partly through inertia within government agencies. In Australia, for example, prior to the statutory reforms initiated by the Council of Australian Governments water reform framework in the 1990s, many Australian states managed groundwater and surface water through separate government agencies, an approach beset by rivalry and poor communication.

In general, the time lags inherent in the dynamic response of groundwater to development have been ignored by water management agencies, decades after scientific understanding of the issue was consolidated. The effects of groundwater overdraft may take decades or centuries to manifest themselves. The science has been available to make these calculations for decades; however, in general water management agencies often ignore such effects that have longer timeframes. Management agencies need to define and use appropriate timeframes in groundwater planning. This will mean calculating groundwater withdrawal permits based on predicted effects decades, sometimes centuries in the future.

For example, a modelling study investigated a situation where groundwater extraction in an intermontane basin withdrew the entire annual recharge, leaving ‘nothing’ for the natural groundwater-dependent vegetation community. Even when the borefield was situated close to the vegetation, 30% of the original vegetation demand could still be met by the lag inherent in the system after 100 years. By year 500, this had reduced to 0%, signalling complete death of the groundwater-dependent vegetation. EMsmile (talk) 14:49, 19 January 2023 (UTC)

Groundwater pollution content replaced with excerpt

Instead of this text I have now added an excerpt from groundwater pollution. That excerpt is more up to date and better written. Also that image with the iron oxide staining didn't say very much so I have removed that as well. EMsmile (talk) 14:59, 19 January 2023 (UTC)

Iron (III) oxide staining (after water capillary rise in a wall) caused by oxidation of dissolved iron (II) and its subsequent precipitation, from an unconfined aquifer in karst topography. Perth, Western Australia.

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Polluted groundwater is less visible, but more difficult to clean up, than pollution in rivers and lakes. Groundwater pollution most often results from improper disposal of wastes on land. Major sources include industrial and household chemicals and garbage landfills, industrial waste lagoons, tailings and process wastewater from mines, oil field brine pits, leaking underground oil storage tanks and pipelines, sewage sludge and septic systems. Polluted groundwater is mapped by sampling soils and groundwater near suspected or known sources of pollution, to determine the extent of the pollution, and to aid in the design of groundwater remediation systems. Preventing groundwater pollution near potential sources such as landfills requires lining the bottom of a landfill with watertight materials, collecting any leachate with drains, and keeping rainwater off any potential contaminants, along with regular monitoring of nearby groundwater to verify that contaminants have not leaked into the groundwater. In some areas, the groundwater can become contaminated by arsenic and other mineral poisons.

Groundwater pollution, from pollutants released to the ground that can work their way down into groundwater, can create a contaminant plume within an aquifer. Pollution can occur from landfills, naturally occurring arsenic, on-site sanitation systems or other point sources, such as petrol stations with leaking underground storage tanks, or leaking sewers.

Movement of water and dispersion within the aquifer spreads the pollutant over a wider area, its advancing boundary often called a plume edge, which can then intersect with groundwater wells or daylight into surface water such as seeps and springs, making the water supplies unsafe for humans and wildlife. Different mechanism have influence on the transport of pollutants, e.g. diffusion, adsorption, precipitation, decay, in the groundwater. The interaction of groundwater contamination with surface waters is analyzed by use of hydrology transport models.

The danger of pollution of municipal supplies is minimized by locating wells in areas of deep groundwater and impermeable soils, and careful testing and monitoring of the aquifer and nearby potential pollution sources.

Around one-third of the world's population drinks water from groundwater resources. Of this, about 10 percent, approximately 300 million people, obtains water from groundwater resources that are heavily polluted with arsenic or fluoride. These trace elements derive mainly from natural sources by leaching from rock and sediments.

References

EMsmile (talk) 14:59, 19 January 2023 (UTC)

Wiki Education assignment: Plant Ecology Winter 2023

This article was the subject of a Wiki Education Foundation-supported course assignment, between 16 January 2023 and 10 April 2023. Further details are available on the course page. Student editor(s): Azadirachta indica (article contribs).

— Assignment last updated by Azadirachta indica (talk) 16:13, 24 February 2023 (UTC)