Flood

Floods were created by an over-abundance of water in a particular location. They were usually considered dangerous things to be avoided, but they were nevertheless sometimes intentionally created.

On Earth, precautions were taken against flooding. For instance, by the early 21st century, Londoners had erected the Thames Flood Barrier to protect against flooding. (TV: The Runaway Bride) Around the year 5000, when combating the Second Ice Age, the World Plan had to consider the possibility of widespread flooding that could be caused by melting glaciers with ionisers. (TV: The Ice Warriors)

Despite the human tendency to protect against flooding, they could not be entirely prevented, likely because they had so many possible causes. Rain or swiftly-melting ice and snow were obviously major causes, but there were others. For instance, a Pescaton ship once crashed into the Thames Estuary, and the knock-on effect was flooding up and down the River Thames itself. (AUDIO: Doctor Who and the Pescatons) In December 1999, flood warnings went out along the Napa and Russian Rivers in California, caused by opening the Eye of Harmony. (TV: Doctor Who)

Sometimes, areas were intentionally flooded, as when a river was dammed to create hydroelectricity. Lake Silencio was evidently the result of "flooding for electricity", since Rory Williams was captured by Canton Everett Delaware III on a hydroelectric power station overlooking the lake. (TV: Day of the Moon) Likewise, the Welsh village of Cwmblaidd was flooded to create a new power station. (PROSE: The Book of Jahi)