Seasonal High Water Table
Understanding High Water Table in New Jersey
You may have a drainage problem around your home if the basement is wet, the yard is flooded periodically, water ponds on the lawn following rain events, or you have premature septic system failure. In order to develop solutions to these problems you must first determine if the problems are being created by excess surface water, subsurface drainage or in some cases both. Excess surface water can often be handled by re-directing drainage on the surface of the ground and providing an outlet point for that drainage, see ‘Drainage Around Your Home’ handout for more information.
Subsurface drainage is often quite different from surface drainage and the specific problem must be understood in order to create solutions. Subsurface drainage usually deals with a soil’s high water table characteristics. The water table is the level at which the soil is saturated with water. This level may fluctuate by several feet throughout the year depending on soil type, landscape and weather conditions.
When discussing high water table conditions, it is important to distinguish between ‘apparent’ and ‘perched’ water tables because drainage solutions for each may be quite different. There are specific limitations to soils with apparent or perched water table conditions. Construction of homes, basements, septic systems and ponds must be carefully considered when dealing with high water table conditions. Saturated soils often have decreased strength for building structures, may slough during excavation, may keep basements wet or sump pumps running continuously or cause septic system to fail.
Of the 52 different soil types described in Soil Survey, 29 are characterized as having either an apparent or perched water table. An apparent water table is a thick zone of saturated pores in the soil and is relatively permanent and often expansive. Consequently, this type of ground water condition is sometimes referred to as a high water table. A perched water table stands above an unsaturated zone separated from the permanent water table by an impermeable layer of soil or rock material. A seasonal water table exists when typical ground water conditions rise during wetter times of the year. Perched water and seasonal water tables can be and can be expansive or localized.
Soils in New Jersey that contain apparent water tables exhibit high water table conditions from November through May. During these months the saturated zone can be from ground level to 2.0 feet below the surface. Perched (seasonal) water tables average 0.5 – 3.0 feet below the surface and can occur from November through June.
In order to determine if high water tables may affect your project consult Effective Basement Solution to determine the soil type involved. Each soil type is listed along with potential high water table conditions and associated limitations for use. The Soil & Water Conservation District can help interpret the information. A soil scientist or consulting engineer can conduct test holes or borings for site-specific water table conditions. The soil types listed below are known to have high water table conditions associated with them and should be carefully considered when planning a project.Effective Basement Solution is a Company to contact even before you Start Building you new Home ‘ we can be Reach at 1800 957 0075 www.effectivewaterproofing.com