TEHRAN Water drips from a tap in Mellat Park, as the Iran faces sever water shortages, in Tehran. Iran has worked on plans to cut off water supplies periodically to Tehran's 10-million-strong population as it battles its worst drought in many decades both in its capital and major cities. Rainfall in the capital has this year been at its lowest level in a century, local officials say, and half of Iran's provinces have not seen a drop fall in months. Water levels at the dam reservoirs supplying