Hardpan

Many areas of Santa Maria/Orcutt are built on sandy terrace soils. Over eons of time the minerals in the soil and water have combined to cement the soil particles together into a poor grade of sandstone. These layers of sandstone, also called hardpan at times, may be near the surface or several feet deep in the soil. The layers may also be a few inches to several feet thick. It is difficult and sometimes impossible for water to penetrate these sandstone layers. Another cause of the problem may be soil compaction caused by heavy equipment during the land preparation and grading process at the time your home was built. Hence, water piles up on top and what may be termed a temporary “perched water table” develops. Depending on the severity (thickness, extent) of the compact layers and the location, there are several options for improving the situation. First, you need to dig several holes in your yard to get an idea of how deep the layer is in the soil. Next you need to determine how thick it is. A screw-type auger may be used for this purpose. If the layer is thin (a few inches), drill holes through it at regular intervals over the problem area. The holes should be two to three inches in diameter and backfilled with coarse material (gravel) so they stay open. If the layer is thick, things get more complicated. Changing the slope of the yard, so that water drains off, is an option. Installing subsurface perforated drainage tiles, which take the water out to the street, may be another option. If the affected area is a landscape or garden, make raised beds so that some of the soil can drain sufficiently to allow for good plant growth. Also add compost and other organic matter to the soil to help improve drainage. Water management in this situation will also be important. Where water tends to puddle, it may be necessary to water at more frequent intervals but for a short time. This way only the top several inches of soil get wet, the plants are watered, but water does not back up. Installing a drip irrigation system, which delivers water only to where it is needed, may be another consideration.