A spring is a spot where the water table seeps onto the surface of the soil. Springs are usually on hillsides or slopes, and occur where the slope of the land intercepts an aquifer—a layer of soil that carries water.
Most springs are persistent or seasonal wet spots, but some actively seep or even gush onto the surface of the soil.
Intermittent springs may be created when hillsides are terraced for housing developments. Drainage water from homes farther up the slope can appear in your yard when a neighbor overwaters her garden. The water drains through the soil along an aquifer to emerge lower down, where the aquifer was cut.
Making a Spring Into a Water Feature
You can use a spring as a source of water for a pool or birdbath. Beginning at the top of the wet area, dig a trench into the hillside to tap the aquifer. As you dig, more and more water will appear. Slope the trench slightly downhill so the water will run out. Lay a drain line (a perforated pipe) in the trench and backfill around the pipe with gravel. The spring water will drain through the pipe, and the soil at the surface will dry out.
Use the water to keep a birdbath or pond filled or, if you are lucky enough the have a substantial flow, create a creek across your garden.
Drying up a Spring
To dry up a spring, install an interception drain line. Follow the directions in Installing French Drains to put a drain line where it will cut the aquifer that feeds the spring and drain the water away before it emerges on the surface.
Locate the aquifer by digging a trench as described above. At a point where you have a substantial flow, dig a second trench across the slope and deep enough to intercept the water. Angle the drain line downhill and install it to an outfall. Water in the aquifer will enter the drain line and be carried away before it reaches the surface of the soil.