ERJ190 flight crew experienced a flight control issue associated with the loss of the number one hydraulic system.

Narrative

At 10;000 on arrival 'Spoiler Fault' annunciated. The First Officer was flying while the Captain managed the QRH. Procedure completed. Determined no spoilers up. 'HYD 1 LO PRESS' annunciated. Looked at synoptic page - HYD 1 fluid volume '0%'. Completed QRH procedure for 'HYD 1 LO PRESS'; concluded loss of HYD System 1. Continued normally on arrival. Called Approach to tell them of malfunction and requested slight extension of final. First Officer reported that aircraft was flying normal. Continued with Descent/Approach Checklist for loss of HYD 1. Turned base and final. When we set full flaps the aircraft started heavy buffet and rolled right. The First Officer had to add considerable aileron to maintain wings level. I called for a speed increase of 10 knots and declared an emergency with Tower. We landed and rolled out normally. Fire/Rescue looked the aircraft over and we agreed it was safe to taxi to the gate. We noticed that the brakes were very hot -- in the yellow (400 degrees). Discussed this with maintenance and they said bring it to the gate - they would notify personnel that brakes were hot. Parked aircraft. Passengers disembarked normally. Suspect leak in HYD 1 system near spoiler. Passengers reported seeing spoilers pop up and fluid spray out while in air. A Flight Attendant reported this to me after the event. I suspect that when the spoiler fault annunciated; there was a spoiler panel up slightly; The QRH calls for a different procedure when any spoiler panel is up; using added speed and Flaps 5; etc. We should have checked the synoptic page for a spoiler panel up. When I asked the First Officer if a spoiler was up; he thought no. QRH might suggest checking synoptic page; since Spoiler Panel Up changes nature of HYD SYSTEM 1 LOSS procedure. In retrospect; I should have slowed down the operation more; and declared an emergency earlier; at first sign of hydraulic system trouble. Also; I should have taken the time to communicate better with the Flight Attendants and Dispatch. Initially with the HYD SYS 1 LOSS; I believed the operation would continue normally; without anyone in the cabin noticing a problem. Both the First Officer and I did not consider it to be a big problem. However; on final we were surprised by the buffet and roll. We had plenty of fuel to hold or extend final. All checklists were completed; but communication suffered because I did not take more time in the air to thoroughly check those blocks. Also; with brakes so hot; leaking hydraulic fluid could have been a fire hazard.