A former employee with Atlanta's Department of Watershed Management admitted Thursday that he stole thousands of dollars in metals from water facilities to support his drug habit, Channel 2 Action News reported.

Jonathan MacDonald was charged with theft by a government employee and criminal trespass. He stole metal grates, solar panels and other equipment, then pawned or sold them, the department said.

“There were actually 64 metal gratings taken with a replacement cost of over $400,000 just for the metal gratings,” Senior Assistant Fulton County District Attorney Brad Malkin told Channel 2.

MacDonald was arrested last September after stolen solar panels were discovered at E Pawn on Donald Lee Hollowell Parkway in northwest Atlanta. Police have said MacDonald told them that he had a heroin problem and E Pawn just happened to be near his dealer. His targets were alleged to have included the watershed facility on Monroe Drive and a pumping station off Fulton Industrial Boulevard.

MacDonald, who already has spent six months in jail, faces an 18-month prison sentence and eight years on probation, Channel 2 said. He has 10 years to pay the court-ordered restitution of $35,000 -- the value of the items at the time they were stolen.

The Department of Watershed Management said it had implemented new security measures since the thefts, which were alleged to have happened during the summer and fall of 2011.