Wetlands have a big effect on groundwater, the amount of water below the surface of the land.

湿地对地下水，即地表以下的水量影响很大。

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They gathered hundreds of sea creatures and water samples to measure the garbage patch's effect on ocean environment.

VOA: special.2009.09.22

She outlined the reasons for a more cautious approach, which included the ban or moratorium placed on fracking in other countries, concerns cited by NI Water for the effect of pollution on water supply, and the dangers of well blowouts and earth tremors.

BBC: Hydraulic fracturing

Couldn't it be argued that the extra water would have a positive, rather than adverse effect on English water supplies and therefore the Secretary of State's power might not be exercisable?

BBC: Highly politicised liquid assets

"The California Department of Water Resources will interrupt pumping water from Northern California to Southern California, which will have no effect on the water supply, " said Brown.

CNN: California briefly declares Stage Three power emergency