Despite advancements in the design and construction of buildings, a high water table remains a jinx for homeowners. It usually lies above the crawl space or the basement floor level and can become problematic if the soil around your home is dense and absorbent. With time, a high water table allows groundwater to infiltrate the foundation, causing water damage and structural issues.
There’s nothing you can do to stop the water table if it rises to the level of the basement. It is part of the earth and leveling or re-grading the yard won’t lower it. The water table will rise over a large area, not just around your home.
What Is a High Water Table?
A high water table refers to the point at which the saturated rock and soils join the upper soil layers that have less water. The layer of saturated groundwater could be anywhere from a couple of feet to several feet down a particular zone. Water can come from excess water from elevated grounds or too much rainwater.
These geological formations are common in low-lying areas with poorly drained soils. However, zones with normal water tables may experience seasonal changes, which can push their levels up, leading to severe flooding.
Types of Water Tables
Water tables vary depending on the season or geologic formations. It’s important to understand what you are dealing with:
Perched water tables: When groundwater gets trapped in pockets high up in the earth’s crust, a perched water table will form. This table lies above the usual subsurface groundwater in a given zone and may consist of bedrock material or heavily compacted clay soil, which doesn’t allow water to seep through it. Even if your home is on higher ground, the soil may still get saturated with groundwater.
Seasonal high water tables: During late winter and early spring, the groundwater rises due to snowmelt and increased spring rainfall. Water from the surface infiltrates the ground, pushing up the water table. If water won’t drain away for several days in winter and early spring, you likely have a high water table.
Ways It Affects You
A high water table can impact your home and the foundation in the following ways.
Foundation shift: Where the local water table sits close to the surface, groundwater can push against the lower side of the foundation. This phenomenon is known as hydrostatic pressure. This pressure may cause water to seep through the foundation’s bottom and even permeate the concrete slab. If the pressure is extreme, it could shift foundation walls and structures, like decks.
Humidity issues: Even if foundation cracks or shifting don’t occur, you could still end up with humidity issues, which could foster wood rot, rust, and mold growth. The increased moisture levels will certainly degrade and compromise your wooden structures.
Measuring the Water Table
The best way of determining the depth of the water table near you at any time is by measuring the water level in a shallow well using tape. If there are no wells, surface geophysical techniques can be used. The common ones being acoustic or electric probes. Whenever you see a pond in the yard after a heavy downpour, remember the water table. Chances are the puddle sits on top of the water table and has exceeded your yard’s grade.
Why Do Water Tables Rise and Fall?
Water tables are impacted by ground cover, precipitation, proximity to water bodies, tides, and irrigation. They also fluctuate from year to year by climatic changes and the volume of water drawn from the underground. Whenever there is a heavy downpour, the water table may get saturated completely. Not all the water that penetrates the unsaturated zone is used by plants as it’s still shallow. With further penetration, more water will get to the water table, causing it to rise. Come summer, the water table will fall as water is lost to evaporation.
Dealing with a high water table can be frustrating. Here are solutions that can help mitigate their effects on your home.
Yard drainage: Surface and subsurface drainage can help channel stormwater runoffs away from your home so it won’t infiltrate the foundation or weaken the structure.
Swales: These are shallow depressions that collect stormwater and ditch them on the municipal drain. Depending on your yard’s grading, they can carry the water towards the front or rear of the property.
Underground pipes: Some sites require more than surface drainage. This is where perforated pipes or weeping tiles come in. They’re laid on a gravel bed or a trench that’s dug below the soil grade. Sloping slightly towards the discharge point, this system captures water that tries to infiltrate the soil.
Yard drainage systems: Plants and lawns are useful as leaves and blades slow the runoff. Also, their roots absorb the water. Combining yard drainage with surface drainage helps slow down runoffs and water infiltration.
Basement and foundation waterproofing: Solutions such as sump pumps and interior drains can help mitigate water damage, which is prevalent in areas with high water tables.
If your home sits close to a high water table, don’t fret. Contact the expert team at JES Foundation Repair for a free inspection and repair estimate. These professionals can perform the necessary foundation repairs and basement waterproofing to mitigate water damage. We use industry-approved solutions that also provide lasting results, so your home stays safe and dry.