I believe you mean 44.64 MHz, 46.64 is not licensed to East Bay Regional Parks. I did a FCC search for all their licenses and found 19 different licenses for them. I could not find any input frequencies other than 45.04, which is the input for 44.76. I did see a license for 44.68/45.00 but they seem to be a pair. There is a 46.34 licensed but I haven't checked that for activity.
The main license appears to be KBB840 with 44.64, 44.76, 44.96, 45.04, 46.34, 150.805 and 153.8675. Another license with multiple sites is WNVK857 with 44.68 and 45.00. There is a license with mainly fire frequencies, WRL694, with 154.07, 154.235, 154.28 and 154.355. WNCU470 and WPBZ620 license 151.325 as well. All the other licenses are repeats for their low band frequencies.
I also believe they will eventually migrate over to EBRCS.