CHA LCL CTLR RELEASED DEP WITHOUT APPROPRIATE COORD WITH DEP CTLR RESULTING IN NEAR LOSS OF SEPARATION AT 2500 FT.

Narrative

I WAS WORKING LCL CTL AT CHA COMBINED WITH THE CIC POS. TRAINEE WORKING GND AND CLRNC (HE/SHE CERTIFIED ON THOSE POS). THIS WAS THE FIRST DAY OF HAVING OUR MAIN RWY CLOSED FOR CONSTRUCTION. WE WERE USING OUR XING RWY FOR ARRS AND DEPS. AT SOME POINT; ONE OF THE COMMUTER FLTS RECEIVED PERMISSION FROM ARPT MGMNT TO USE THE LONG RWY (THE ONE THAT WAS CLOSED). THE DEP HAD A FLOW CTL SLOT TIME SO THEY WERE HOLDING ON THE RAMP WAITING ON THE TIME. MEANWHILE; I HAD HEARD GND CTL COORDINATING WITH THE ARPT MGMNT PERSONNEL CONCERNING THE DEP. I WAS TOLD THAT EVERYTHING WAS WORKED OUT AND THAT THEY WERE APPROVED FOR DEP ON THE LONG (CLOSED) RWY. IN OTHER WORDS; THE RWY WOULD BE OPENED BRIEFLY FOR THAT ONE DEP. ALSO; AT THAT TIME; I HAD ACFT CALL FOR DEP AND A HELI DEPART. I HAD TO RADAR IDENT THE HELI; COMPLETE A FLT PROGRESS STRIP FOR THEIR FLT; FORWARD THE STRIP TO THE TRACON; AND START AN AUTOMATED HDOF. AS SOON AS THE FLOW CTL SLOT TIME ARRIVED; I CONFIRMED WITH THE GND CTLR THAT EVERYTHING WAS OK FOR THE DEP ON THE TEMPORARILY OPENED RWY. AT THAT TIME; I ISSUED BACK-TAXI INSTRUCTIONS AND ALSO ISSUED THE TKOF CLRNC. JUST AFTER THE ACFT DEPARTED I REALIZED THAT I HAD NOT COORD A RELEASE WITH THE DEP CTLR AND THAT THERE WAS TFC FOR THE DEP. I IMMEDIATELY COORD WITH THE DEP CTLR AND TURNED THE DEP AWAY FROM THE TFC XING HIS DEP PATH. I DO NOT BELIEVE THAT THERE WAS LESS THAN STANDARD SEPARATION BTWN THE ACFT. ALSO; I APPLIED VISUAL SEPARATION BTWN THE 2 ACFT. THERE WAS NO FURTHER PROBS. I DO BELIEVE THAT THERE WERE MANY DISTRS THAT CAME INTO PLAY. 1) A MAJOR TXWY RESURFACING PROJECT UNDERWAY. 2) USING OUR SHORT XING RWY AS THE ACTIVE. 3) THE LONG NORMALLY ACTIVE RWY BEING CLOSED. 4) WORKING LCL COMBINED WITH THE CIC POS. OTHER FACTORS THAT COULD HAVE CAUSED ME TO MAKE THE MISTAKE: 1) HAVING AN INEXPERIENCED TRAINEE WORKING GND. A MORE EXPERIENCED CTLR MAY HAVE CAUGHT MY MISTAKE (AND WOULD HAVE BEEN WORKING THE CIC POS). 2) THE DEP WAS USING OUR PRIMARY RWY THAT WOULD NORMALLY HAVE AUTOMATIC RELEASES. (WE HAD AUTOMATIC RELEASED ON THE OTHER RWY AT THE TIME.)