By the end of March, a fifth of the town had been covered by lava flows, and increased pumping capacity was required. Thirty-two pumps, each with a capacity of up to 1000 litres per second (265 US gallons per second), were brought in from the United States. After these pumps began to cool the flow advancing towards the town, its movement slowed dramatically and soon stopped. Failure of pump shafts became a problem after a few weeks, probably because they were designed for pumping oil rather than water, and new and improved shafts had to be manufactured in Reykjavík and brought in.