MD80 Captain experiences low oil quantity then low oil pressure on the left engine during descent for landing. The engine is shut down and an emergency is declared before landing at destination airport.

Narrative

We were in the descent approximately 80 miles from the field and I noticed the oil quantity at 2 then 1 then zero. I pulled out the QRH and followed the procedures. We still had oil pressure and temperature was normal. I then tried calling Maintenance Control but could not reach them. Next I called to get a phone patch but stopped when we got a light for low oil pressure. Again we pulled out the QRH and followed the procedures. We shut down the number one engine and declared an emergency. I then pick up the phone and called my lead to tell him what was going on and to prepare the cabin. At this point we were close enough to reach Maintenance Control over the radio and informed them what was going on and that we had shut the engine down and declared an emergency. I then pick up the phone and made a PA to the passengers to inform them what was going on. We gave ATC all the information that they requested in regards to the flight and people on board. Approach Control gave us the current weather and our option on which runway to land. Approach Control cleared us for a visual approach about 20 miles from the field. All checklists were followed and QRH procedures. We landed flaps 28 with medium auto brakes. We rolled out to the taxiway and exited the runway. Everything was under control so we informed the Tower that we could taxi to the gate. The emergency equipment followed us to the gate.