In the southwest region of the USA, the worst sun exposure occurs as the sun traverses the western end of the sky. Our house is graced by two lovely full-grown mulberry trees that shade our western exposure. If this were not the case, we would have planted two fast-growing trees at the west side of the house.
Thus, the first step we undertook over the course of several years was to redesign the flow of water at the front of our site. We have a steep front yard and the existing water flow allowed storm water to drain directly into the street, washing away our topsoil, reducing retained landscape water and exposing tree roots. We added a rock landscape at the lowest edge of the site that stopped water from leaving the site. The photo shows the topography before we added the rock landscape.
Below are some great guidelines cribbed from the City of Palo Alto, California:
Provide a minimum slope of 2% away from the building foundation, as required by the Uniform Building Code.
The drainage for surface runoff should not require the use of area drains or pipe collection systems.
Avoid the use of dry wells.
In no case shall the final grading increase the normal sheet flow onto adjacent properties.
Downspouts should directed to splash blocks (minimum 2 feet long) that deflect the water away from the building.
Direct roof and site drainage to pervious areas of the site. Design the site drainage to take full advantage of these pervious areas.
Provide drainage paths on and from impervious areas (driveways, patios, etc.) that should always be sheet-flow drained into a pervious area. No catching of this water into area drains should occur.
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