| Hello,
My parents recently removed the backyard lawn. They've had a patio installed and the rest of the lawn was dug up and the intent is to plant shrubs and plants into the new extra space, extending the gardens.
The yard is very uneven and water tends to pool and flood during bad storms. My mom and I believe if dig out the existing plantings, break up the (very compacted) existing soil with a rototiller and mix in some more amendments (perlite for drainage, some compost, ect) to better the soil and rake the yard out so it's level to about an inch below the patio, we'll have better overall drainage since the water won't pool and will get into the soil easier. We both believe that since the yard will be level and lower than the patio, water will take the path of least resistance and spread out over the entire yard, which is a good amount if surface area, before we'll start seeing it overtopping the patio.
My dad is convinced that if we do this the patio will flood during storms and we need to have one very low area that water will drain into.
Any suggestions over who might be right here? If my dad is correct then I'm suggesting my parents look into a rain garden, but I find it hard to believe with such a large area for water to spread, and soil that's not compacted so the water gets absorbed and doesn't pool, that we're going to see it flooding over the patio. | 
