In the Southern Hemisphere, where the June solstice is known as the shortest day of the year, it marks the first day of astronomical winter, but the middle of winter in meteorological terms.
Backfill refers to products or materials used to fill excavations. The most common form is composed of a mixture of gypsum and calcium bentonite. Apart from filling holes, one of the primary purposes is to mantle sacrificial anodes under the ground.
Infill is the urban planning term for the rededication of land in an urban environment, usually open-space, to new construction. Infill also applies within an urban polity to construction on any undeveloped land that is not on the urban margin. The slightly broader term land-recycling is sometimes used instead. Infill has been promoted as an economical use of existing infrastructure and a remedy for urban sprawl. Its detractors view it as overloading urban services, including increased traffic