TOKYO — Two years after a triple meltdown that grew into the world’s second worst nuclear disaster, the Fukushima Daiichi nuclear power plant is faced with a new crisis: a flood of highly radioactive wastewater that workers are struggling to contain.

Groundwater is pouring into the plant’s ravaged reactor buildings at a rate of almost 75 gallons a minute. It becomes highly contaminated there, before being pumped out to keep from swamping a critical cooling system. A small army of workers has struggled to contain the continuous flow of radioactive wastewater, relying on hulking gray and silver storage tanks sprawling over 42 acres of parking lots and lawns. The tanks hold the equivalent of 112 Olympic-size pools.

But even they are not enough to handle the tons of strontium-laced water at the plant — a reflection of the scale of the 2011 disaster and, in critics’ view, ad hoc decision making by the company that runs the plant and the regulators who oversee it. In a sign of the sheer size of the problem, the operator of the plant, Tokyo Electric Power Company, or Tepco, plans to chop down a small forest on its southern edge to make room for hundreds more tanks, a task that became more urgent when underground pits built to handle the overflow sprang leaks in recent weeks.

“The water keeps increasing every minute, no matter whether we eat, sleep or work,” said Masayuki Ono, a general manager with Tepco who acts as a company spokesman. “It feels like we are constantly being chased, but we are doing our best to stay a step in front.”