Moving water away from existing patio
Any combination of surface grading, surface channels, trenches, underground pipes, etc. will work with just two rules,
1. Water flows downhill.
2. (regarding underground pipes less than about 3 feet deep) Water freezes.
You could allow/designate there to be a low point where water will accumulate, dig a pit (perhaps the size of an oil drum, 55 gallons), and pump it out with a hose over a walkway over to a lower area during times when the porous sides of the pit can't absorb the water as fast as the water accumulates (the role of the pit changes by itself from dry well to sump).
The disadvantages of crab apple trees. In summer, the apples are too sour to pick and eat. In winter the birds come and leave dropping all over the place.
Last edited by AllanJ; 09-28-2011 at 08:52 AM.