ACFT EQUIP PROB MALFUNCTION CREATES NEED FOR EMER DECLARED; EMER GND EQUIP CALLED OUT.

Narrative

ENRTE APCHING MCI DEST LOW HYD QUANTITY ALERT APPEARED. PUMPS WERE TURNED OFF IN ACCORDANCE WITH PROCS. QUANTITY IN SYS STABILIZED AT ABOUT 40 PERCENT. THIS WAS THE ACFT'S PRIMARY (#1) SYS; WHICH CTLS LNDG GEAR; FLAPS; NOSEWHEEL STEERING; THRUST REVERSERS AND OTHER MAJOR SYS. WE CONTINUED TO THE ARPT IN CRUISE CONFIGN WITH THE SYS 1 PUMPS OFF. APCHING THE FIELD WE RECEIVED A 10 MI STRAIGHT-IN AS REQUESTED. THE PUMPS WERE SELECTED ON TO LOWER LNDG GEAR AND FLAPS; THEN SELECTED OFF AGAIN TO CONSERVE FLUID. GEAR AND FLAPS LOWERED NORMALLY AND QUANTITY READ OVER 35 PERCENT AFTER THE PUMPS WERE TURNED OFF. JUST PRIOR TO TOUCHDOWN (WITH THE FO FLYING); I SELECTED THE PUMPS ON AGAIN. NOSEWHEEL STEERING; BRAKES; AND THRUST REVERSERS ALL OPERATED NORMALLY. I TURNED OFF 1 OF THE PUMPS; HOPING THAT IT MAY HAVE BEEN LEAKING (A RANDOM CHANCE) AND I TOOK CTL OF THE AIRPLANE FOR A SHORT TAXI TO THE GATE. ONCE BRAKES WERE SET AT THE GATE THE PUMPS WERE AGAIN TURNED OFF AND ENGS WERE SHUT DOWN. WE STILL HAD OVER 25 PERCENT FLUID REMAINING. I HAD REQUESTED THE RESCUE EQUIP AS A PRECAUTION AND THEY WERE RELEASED WHEN WE GOT TO THE GATE. MAINT DISCOVERED A HYD LEAK IN THE VICINITY OF THE WHEEL WELLS.