Audio Transcript:

The US says it will send thousands of troops to Haiti to help rescue efforts in the wake of the devastating earthquake. President Barack Obama pledged one of the biggest relief efforts in recent US history and said Haiti would ?not be forgotten? in its hour of need. One critical need in these early days after the earthquake is clean drinking water, as The World's Matthew Bell reports.

JEB SHARP: One critical need in these early days after the earthquake is clean drinking water. A lack of water could further weaken those who are injured and the contamination of drinking water supplies could threaten all survivors. The World's Matthew Bell reports.

MATTHEW BELL: A medical worker in Haiti speaking to the Associated Press put it this way. ?There's no water. There's nothing. Thirsty people are going to die.? Patrick McCormack is a spokesman for UNICEF in New York. He says water is a top priority for Haiti right now.

PATRICK MCCORMACK: We understand that the water supply most has been cut off. So you've got a lot of bad water lying around and kids are very tempted to drink it. So we need to get the water in there as soon as possible otherwise you can get the outbreak of disease from bad water.

BELL: McCormack says aid groups have started distributing bottled water and water purification tablets. He says supplies are being delivered to Haiti on trucks form the Dominican Republic next door. More is on the way by boat and by aircraft.

MCCORMACK: It's coming from all over the place. We've got supplies coming from our supply division in Copenhagen. We've got a plane coming from Dubai. I'm sure there are lots of planes coming from the US, from Miami, from all over.

BELL: People who have been injured are particularly vulnerable to dehydration. That means medical facilities are in desperate need of clean water right now. Mugur Dumitreche is a water and sanitation expert with the aid group Mercy Corps. He's in Switzerland trying to figure out what he'll be up against when he arrives in Haiti this weekend.

MCCORMACK: The timeline is first we deal with the quantity. We have to make sure that they have enough. And then we deal with the quality. It's like a high priority but nonetheless are less separated and the amount of water available, readily available, immediately.

BELL: Dumitreche says what's needed after a disaster like this is about four gallons of water per person per day. He says hospitals need more than twice that much. Not just for patients but for things like providing clean bedding. Aid groups aren't just sending water to Haiti but also water purification equipment. Dumitreche says he and his team will be setting up mobile purification units. These can quickly convert contaminated water into clean drinkable water that people can carry home in plastic jugs. But to do that his team will first have to find sources of water and that could be a challenge in parts of Haiti.

MCCORMACK: It seems that the villages that were using wells previously most of them are still working so it's okay. The mountain villages or towns that had water supplies fed by springs from the mountains they might have had problems due to landslides.

BELL: In coastal areas the ocean could be a source of drinking water. Some aid groups may bring desalinization equipment. But Dumitreche says that process is both slow and expensive. In many parts of Haiti problems with clean water existed long before the earthquake and Dumitreche says that could be an advantage because many Haitians already know about the dangers of contaminated water. They're familiar with how to filter water and how to use water treatment tablets. Now as Haitians try to survive in the aftermath of the earthquake this basic know-how could mean the difference between life and death. For The World I'm Matthew Bell.