Cracks in the courtyard are allowing rainwater to corrode the subterranean steel trusses.

They did not offer protection from the cold, and the tarred fabric soon began to deteriorate, allowing rainwater to enter the cabins.

The other was not putting flashing completely through the parapets, the protective walls on the edges of the roof, allowing rainwater to seep in.

Each pitcher also exhibits a small slit in its side that allows excess rainwater to drain away, similar to the overflow on a sink.

They also physically protect the soil surface from heavy rain, while allowing rainwater to percolate slowly, preventing run-off and erosion.

Besides, they are laid at a slight angle, lower on the outside than on the inside, thus allowing rainwater to run off.

This incline will allow rainwater to run off the steps.

Four of the columns which surround the building are hollow and,with a length of chain dangling in each, allows rainwater to drain down.

On three sides there are nine inch walls and one side is left open to allow rainwater to fill the structure.

Under the plan, new development must allow rainwater to seep into the ground, filling groundwater supplies that feed into wells and reservoirs.