why doesn't water penetrate the soil?
Answers:
Ground water absorbtion, also know as percolation, depends on lots of things. The two previous answers hit on some good points. As water is absorbed, it carries with it minute particles which fill the air spaces between the grains of soil. As more and more air spaces fill, the water simply has no place to go...sort of acts like a plug. The more porus the soil, i.e., sand for instance, the less "plugging up" occurs. However, even sand has limits. That's one of the reasons there are flash floods in deserts. The more water on the surface, the more time and depth required to absorb. Surface hardness will also play a role. If the ground is hard by nature, the longer it will take for surface water to penetrate. So...time, type of soil and compactness all control surface absorbtion.
Other answers:
it takes a while
it takes a while
either you have clay or the soil is already soaked
it's too dry it takes awhile
Water always does penetrate the soil, sometimes it just takes longer. It then enters the water table, and flows down hill. It may take longer for the water to penetrate if the soil is saturated, because it has to enter the water table, and flow away.
The water is not penetrating the soil probably because the ground is already water soaked and just cannot absorb any more , right now, they call this water logged.
Has it been raining a lot in your area or maybe the snowmelt is just too fast?
It will be absorbed, just takes a little time.
This time of year the ground is still frozen. Also you my have compacted dirt. You may need to airiate your lawn.
There is a scientific reason for that:
The soil atoms are to dense so that water has no room.
It mostly happens when it is dry or sometimes for the soil's atomic structure itself.
If the soil has the percentage of sand more, than it absorbs more water.
In Florida we have hydrophobic soil - it never gets wet due to a fungus coating on the individual grains of dirt. I use diluted dish soap - not antibactirial as it will kill all - to get the soil to finally start absorbing water. This can take quite a few dousings to work.