There is a really interesting example of the role of the surface vegetation for groundwater in Bamberger Ranch[1] in Central Texas.
Central Texas was massively overgrazed by cattle in the 1800's and 1900's, and the ecosystem was completely transformed from prairie grass dominant to cedar and mesquite dominant vegetation. This resulted in a drastic loss of groundwater and utterly transformed the ecosystem.
David Bamberger restored 5,500 acres to close to original condition and the results are amazing.