Construction starts rose 10% in April from March levels, thanks in part to two megaprojects that got under way during the month, Dodge Data & Analytics reports.

Dodge D&A’s latest monthly look at new-construction volume, released on May 21, showed that April starts climbed to an annual rate of $698.7 billion, seasonally adjusted.

But excluding $1-billion-plus projects, April’s volume was down 3% from the previous month, the company noted.  (ENR is part of Dodge D&A.)

The April results received a major boost from an $8.1-billion Sasol petrochemical plant in Louisiana and a $1.2-billion mixed-use high-rise at Hudson Yards in New York City, both of which began last month.

Dodge D&A also said that, for the first four months of 2015, total construction starts soared 24% year over year, to $208.2 billion, not seasonally adjusted.

When megaprojects of more than $1 billion are excluded, the January-April total still was a 10% gain from the year-earlier amount.

April's starts brought the Dodge Index up to 148, compared with March’s 134. The 2000 figure equals 100 for the index. Last year’s index averaged 124.

The major-project starts so far this year have made the monthly swings in volume more volatile, Dodge D&A Chief Economist Robert Murray observed.

Still, Murray discerns some trends. He said in a statement, “For nonresidential building, the upturn is broadening in scope, with its institutional segment continuing the upward movement established in 2014.” Nonresidential surged 58% in April to a $288.9-billion annual rate.

But residential building edged down 3%, to a $245.1-billion annual rate and the nonbuilding segment dipped 17%, to $164.7 billion.

Murray said that within the nonbuilding category “the electric power and gas-plant segment has provided a substantial near-term boost that will soon recede, while public works is beginning to face constraints after surprisingly resilient activity in early 2015.”

Public works fell 17% in April to $164.7 billion, after a 33% rise in March, Dodge D&A said.

The U.S. Census Bureau, which tracks the montly levels of finished construction projects, reported on May 1 that the value of construction put in place dipped 0.6% in March to $966.8 billion, but was up 2% year over year.