4 ms·

"Subsidence" means sinking. In this case, with the fresh water below removed (thus nothing holding it up) the sediment layer between salt and fresh would sink (

"Subsidence" means sinking. In this case, with the fresh water below removed (thus nothing holding it up) the sediment layer between salt and fresh would sink (or subside). At least that's what happens on land. With the weight of the salt water on top, the effect may be even larger. But likely we won't be pumping out enough water to make a measurable difference so it's not a "real" suggestion.

chr1 7y ago
After removing the water and using it, the water will come back into ocean so sinking (or subsiding:) of the sediment layer won't change the water level. The same water that was under the sediment layer will simply move above it. So there won't be any effect independently from the amount of pumping.
- mythrwy 7y ago
  Ah ok, I see your point. But (and getting even more ridiculous here) the water need not necessarily be returned to the ocean. It could be used for instance to water crops inland or recharge inland aquifers that had previously been depleted.
  - chr1 7y ago
    Yes, i think moving water to inland aquifers and dry lake-beds in current deserts should have a significant impact, but unfortunately i have not been able to find a study confirming or disproving this.
    - foobar1962 7y ago
      Australia has huge problems with salinity, where previously dry areas were deforested and irrigated with water sourced from other areas (like the Murrumbidgee Irrigation Area). Saline groundwater rises to the surface and causes the top soil to become irreversibly salty. Re-forestation would solve the problem (deep rooted plants lower the groundwater level) but because the soil is salty, nothing can or will grow there. The areas are now wastelands, good only for salt mining. I remember some research was put into developing salt-tolerant trees specifically to solve the problem, not sure how successful it was.

4 ms·

"Subsidence" means sinking. In this case, with the fresh water below removed (thus nothing holding it up) the sediment layer between salt and fresh would sink (

by mythrwy 7y ago

chr1 7y ago
After removing the water and using it, the water will come back into ocean so sinking (or subsiding:) of the sediment layer won't change the water level. The same water that was under the sediment layer will simply move above it. So there won't be any effect independently from the amount of pumping.
- mythrwy 7y ago
  Ah ok, I see your point. But (and getting even more ridiculous here) the water need not necessarily be returned to the ocean. It could be used for instance to water crops inland or recharge inland aquifers that had previously been depleted.
  - chr1 7y ago
    Yes, i think moving water to inland aquifers and dry lake-beds in current deserts should have a significant impact, but unfortunately i have not been able to find a study confirming or disproving this.
    - foobar1962 7y ago
      Australia has huge problems with salinity, where previously dry areas were deforested and irrigated with water sourced from other areas (like the Murrumbidgee Irrigation Area). Saline groundwater rises to the surface and causes the top soil to become irreversibly salty. Re-forestation would solve the problem (deep rooted plants lower the groundwater level) but because the soil is salty, nothing can or will grow there. The areas are now wastelands, good only for salt mining. I remember some research was put into developing salt-tolerant trees specifically to solve the problem, not sure how successful it was.