Oops, it doesn't look like 'groundwater awareness day' is a national day..

Other days

artists

Artists Day
tulip

Tulip Day
polyamory

Polyamory Day
bonang

Bonang Day
comfy

Comfy Day
bow tie

Bow Tie Day
blanket fort

Blanket Fort Day
gum

Gum Day
cat girl

Cat Girl Day
one

One Day