LIVINGSTON — The Livingston Parish School Board has submitted more data on its reapportionment plan to the U.S. Department of Justice, board attorney Tom Jones said Thursday.

The Justice Department had asked the board in March what the population totals for each board member’s election district would be, based on the 2010 census, if the board did not change any district boundaries, Jones said.

The School Board approved a redistricting plan in December 2011 that will significantly enlarge the parish’s two eastern districts because of population growth in the western half of the parish.

The plan was formally submitted for Justice Department approval on March 4, according to department records.

“What Justice wants to know in pre-clearance is why changes were made and what the effects of those changes will be,” Jones said. “They want to be able to compare before and after, and this will help them get a more complete picture.”

With School Board approval, Jones enlisted the help of demographer Nancy P. Jensen, of Garnet Innovations LLC in Baton Rouge, to provide the requested information.

The supplement was submitted to the department Wednesday and has been acknowledged as received, Jones said.

The Justice Department has until May 3 either to make a determination whether to approve the plan or to inform the School Board that the review period will be extended, department records show.

The School Board’s plan is based on precinct boundaries and population data compiled during the Livingston Parish Council’s redistricting process, during which Jensen also served as a demography consultant.

However, hiccups in the Parish Council’s reapportionment — including a lawsuit challenging the constitutionality of the council’s first-choice plan and the subsequent adoption of a revised plan — have caused difficulties and delays for the School Board’s own planning.

Jones told the School Board in July that the precinct boundary descriptions he had received from the Parish Council reflected the precincts adopted with the council’s first, rather than its final, reapportionment plan.

Parish officials did not have a consolidated list of all precincts and their boundary descriptions, so Jones had to pull ordinances dating as far back as 1998 to determine when each precinct’s last boundary revision occurred, he said.

Another difficulty surfaced in February, when Jones discovered that the precinct population numbers included discrepancies within and across precincts. Those issues also were likely caused by the council’s change of course, Jones said.