SAN JUAN, Puerto Rico -- On Sept. 20, Hurricane Maria made landfall in Puerto Rico. The Category 5 hurricane wreaked havoc and destruction across the island, taking out electrical and communications infrastructure, as well as severely damaging thousands of buildings and homes.

The National Response Framework designates the U.S. Army Corps of Engineers as the lead agency for Emergency Response Function 3, Public Works and Engineering. Under the function, Corps employees provide temporary generator power to critical facilities, inspect critical facilities, clear roadways and remove debris, and install temporary roofs on homes that were damaged during the hurricane.

As the hurricane made landfall, a small contingent from USACE had already deployed to Puerto Rico, to provide support following Hurricane Irma. They rode out Hurricane Maria and immediately started laying the groundwork for what would be one of the largest disaster responses in the Corps' history, in terms of the magnitude of the mission and number of personnel involved.

On Sept. 24, Mobile District's commander, Col. James DeLapp and 13 employees from the Corps' Mobile and other USACE districts boarded a military flight for San Juan, an advanced party that would set up the Corps Puerto Rico Recovery Field Office and assess the missions.

In less than a month, the USACE mission and manpower have grown exponentially.

"We have taken on missions that the Corps doesn't usually do during a disaster response," DeLapp explained. "At the request of FEMA and the Governor of Puerto Rico, USACE is assisting with the repair to Puerto Rico's power grid and with emergency repairs to Guajataca Dam.

"Our planning and response teams have flawlessly executed their missions and are taking bigger and bigger strides to assist the people of Puerto Rico to return to normalcy as soon as possible," DeLapp said.

By the numbers:

The Power Planning and Response Team, personnel from USACE's Albuquerque District and Soldiers from the 249th Engineer Battalion have installed 364 generators at critical facilities and have another 41 installations in progress, according to Reginald Bourgeois, the mission manager for the Temporary Power Team.

Each generator is supporting a critical function. For example, one generator is providing power for the Guaynabo Hospital, a 150-bed facility that sees 40,000 patients a year. Two others are supporting the water pump stations in Manati, Puerto Rico, providing fresh water for a 44,000-resident community. In total, the team has installed generators to support 48 hospitals, 190 water-treatment plants, and 44 wastewater facilities, as well as 30 emergency services centers and the 9-1-1 call center.

The Debris Planning and Response Team, personnel from USACE's New Orleans District, working with more than 220 locally hired contractors have cleared miles of debris from roads and have picked up and properly disposed of more than 62,542 cubic yards of debris, according to Jasmine Smith, the mission manager for the Debris Team.

FEMA has allocated up to $255 million for debris removal. The team has been tasked to complete debris removal within 39 of the 78 municipalities in the territory. Debris removal consists of the pickup, hauling and disposal of construction and demolition (building materials, furniture, metals, etc.) vegetative debris, household hazardous waste, and white goods (refrigerators, dryers, stoves, etc.).

Another aspect of the Recovery Field Office's mission is the temporary roofing initiative, known as "blue roofs" because of the blue plastic material used. The blue roofs are designed to provide temporary protection from the elements so the residents may return from hurricane shelters, safely inhabit their homes and reduce the chance of further damage from the elements. Hurricane Maria damaged the roofs of thousands of homes, hospitals and other critical infrastructure across Puerto Rico, according to Kevin Slattery, the mission manager for the Blue Roof Team. So far, $105 million has been designated for the program.

To be eligible for a temporary roof, the homeowner/landlord must legally agree to allow the Corps' contractors access to the property by signing a Right of Entry form. The team then assesses the home to see if the structure is eligible for a temporary roof. The Blue Roof Team has already collected more than 17,293 Right of Entry forms; conducted nearly 15,380 assessments; and installed more than 3,986 temporary roofs, Slattery said.

The Recovery Field Office is overseeing several other missions, including one that is a unique assignment for the team: performing emergency repairs to the Guajataca Dam, located near Isabella, Puerto Rico. The spillway of the Guajataca Dam was significantly damaged by Hurricane Maria's heavy rains. The dam provides flood-risk management and water supply to approximately 350,000 people.

At the request of FEMA and the Governor of Puerto Rico, the Corps' Puerto Rico Recovery Field Office has coordinated to perform emergency repairs to the dam. Working with the Puerto Rico Electric Power Authority, the agency that owns the dam, and units from every branch of the Department of Defense, the Corps has overseen emergency repairs to prevent further erosion in the dam's spillway and installed pumps that have returned water supply to the communities below the dam.

Over the past few weeks, the Corps team of engineers assessed the damage to the dam and embarked on the emergency repairs, which included placing 505 jersey barriers, weighing between 4,000 and 5,000 pounds each; and 1,300 "supersacks," 3,000-pound sacks filled with sand and rock. Once the emergency repairs are completed, the Corps is assisting the Puerto Rico Electric Power Authority in developing a plan for long-term repairs.

"This has been a massive response to a massive disaster," DeLapp said. "It's hard to understand how catastrophic the damage is until you see it for yourself. Our thoughts and prayers go out to the people of Puerto Rico. But, more than that, we are here working to help Puerto Rico recover as quickly as possible."

"We are picking up debris, installing temporary roofs, providing emergency power to hospitals, other critical facilities, and getting water and wastewater plants up and running," DeLapp said. "We started with a couple of dozen soldiers and civilians who were either already here or managed to fly in on a military flight when most commercial flights were still unavailable. Now, we have close to 600 soldiers and civilians deployed to Puerto Rico. Our numbers are growing exponentially and the number of local contractors we're employing is growing exponentially. And, we're not leaving until we've done everything we can to help the residents of Puerto Rico return to normalcy."