The furrow he was following led toward it, then faded to nothing as the surface changed from soft soil to hard impermeable material.

Most have a central section or core composed of an impermeable material to stop water from seeping through the dam.

Constantly monitored, they are lined with impermeable materials.

Most are made of impermeable material such as rubber, but some incorporate a filter, allowing air, sweat and condensation to slowly pass through.

Each complete ring consists of eight curving segments bolted together and packed with impermeable material at their seams.

If soil is sealed - ie covered with an impermeable material - it's prevented from functioning properly.

Furthermore, the trenches were neither lined nor covered with any impermeable material to prevent the chemical waste from leaking into the soil.

The river is a 'perch' stream, flowing over a bed of impermeable material on top of a porous substrate.

The contaminated soil beneath the former pile is covered with an impermeable material to prevent the infiltration of water and to prevent human contact.

Because of the very large nature of such roofs, it is essential that the outer skin is of a highly impermeable material.

Inner tubes are torus-shaped balloons made from an impermeable material, such as soft, elastic synthetic rubber, to prevent air leakage.

He squoozles glurp of various colors and consistencies between two flat sheets of impermeable materials, such as windowpanes or bathroom tiles.

It was the merest hint, filtered through the impermeable material, yet it suggested the sleek body of a beautiful and vibrant woman or the controls of a finely machined, high-performance racing car.

He folded the limp bag which had once been the water-cylinder, its impermeable material still smelling faintly of chemical slime, and tucked it under one of the ropes of the glider harness.

Industrial chemicals dumped into the partly completed canal by the Hooker Chemical Company from 1947 to 1952 have been removed or contained in one area that was lined with impermeable materials and capped by clay.

There are layers of impermeable material both above and below it and it is under pressure so that when the aquifer is penetrated by a well, the water will rise above the top of the aquifer.

The state had to drill groundwater wells to monitor leakage, cover the sites with impermeable material, and submit an annual report on the feasibility of disposing of the dredged material in a chemical-waste landfill or by incineration.

In the urban areas of Jamaica, there is a high proportion of land area covered with impermeable materials such as asphalt and concrete meaning that rainwater cannot soak into the ground, or is left to run-off into natural water courses.

If an intersection, impermeable material, or other obstruction exists, a marker may be placed nearby but in violation of the above tolerance, on the opposite side of the road on which it would otherwise be placed, or missing altogether.

When sodium silicate is applied as a sealant to cured concrete or the shells of fresh eggs, it chemically reacts with calcium hydroxide or carbonate to form calcium silicate hydrate, sealing pores with a relatively impermeable material.

The risks of leachate generation can be mitigated by properly designed and engineered landfill sites, such as sites that are constructed on geologically impermeable materials or sites that use impermeable liners made of geomembranes or engineered clay.

A closer inspection of construction techniques over the past 30 years will most likely show that the use of impermeable materials like plywood, vinyl siding and plastic, designed to keep moisture out of homes, is also trapping harmful moisture at high levels within exterior walls.