A puddle is a small accumulation of liquid, usually water, on a surface. It can form either by pooling in a depression on the surface, or by surface tension upon a flat surface. Puddles are usually formed from rain water or from irrigation.
A puddle is generally small enough for an adult to step over, shallow enough to walk through, and too small to traverse in a boat or raft. Puddles can be a source of fascination for children. Small wildlife may be attracted to puddles.
Natural puddles and wildlife
Puddles in natural landscapes and habitats, when not resulting from precipitation, can indicate the presence of a seep or spring. They can provide essential moisture for small wildlife, such as birds and insects. Many butterfly (Lepidoptera) species need puddles for mud-puddling to obtain nutrients such as salts and amino acids.
Swallows use the damp loam which gathers in puddles as a form of cement to help to build their nests. The reduction in the number of puddles in the countryside due to intensive farming, urban sprawl, and climate change is partially the cause of a decrease in the swallow population.
Wildlife uses puddles as a drinking source, for bathing (e.g. birds), or in the case of some smaller forms such as tadpoles or mosquito larvae, an entire habitat. Raised constructed puddles, bird baths, are a part of domestic and wildlife gardens as a garden ornament and "micro-habitat" restoration.
Effects on transport
Puddles commonly form during rain, and can cause problems for transport. Due to the angle of the road, puddles tend to be forced by gravity to gather on the edges of the road. This can cause splashing as cars drive through the puddles, which causes water to be sprayed onto pedestrians on the pavement. Irresponsible drivers may do this deliberately, which, in some countries, can lead to prosecution for careless driving.
Puddles commonly form in potholes in a dirt road, or in any other space with a shallow depression and dirt. In such cases, these are sometimes referred to as mud puddles, because mud tends to form in the bottoms, resulting in dirtied wheels or boots when disturbed.
In cold conditions puddles can form patches of ice, which are slippery and difficult to see and can be a hazard to road vehicles and pedestrians.
Puddles tend to evaporate quickly due to the high surface-area-to-volume ratio and tend to be short lived.
In order to deal with puddles, roads and pavements are often built with a camber (technically called 'crowning'), being slightly convex in nature, to force puddles to drain into the gutter, which has storm drain grates to allow the water to drain into the sewers. In addition, some surfaces are made to be porous, allowing the water to drain through the surface to the aquifer below.
Puddles that do not evaporate quickly can become standing water, which can become polluted by decaying organisms and are often home to breeding mosquitos, which can act as vectors for diseases such as malaria and, of more recent concern in certain areas of the world, West Nile Virus.
Medieval legend spoke of one man who was desperate to find building materials for his house, so he stole cobblestones from the road surface. The remaining hole filled with water and a horseman who later walked through the 'puddle' actually found himself drowning. A similar legend, of a young boy drowning in a puddle that formed in a Pothole in a major street in the early years of Seattle, Washington, is told as part of the Seattle Underground Tour.
Puddles are often a source of recreation for children, who regard jumping in puddles as one of the "up-sides" to rain. A children's nursery rhyme records the story of Doctor Foster and his encounter with a puddle in Gloucester.
|Wikimedia Commons has media related to Puddles.|
- Puddling (biology)
- Puddling (engineering)
- Puddling (metallurgy)
- Seep (hydrology)
- Spring (hydrology)
- Driver fined over puddle splash BBC News, 31 October 2005.
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