Generally yes, with time th esoil around your rock fill will migrate into the voids and you will loose volume and hydraulic conductivity (assuming i understand this as a rock filled soakage trench for stormwater) likewise you need to try to prevent sediment cominginto the soakage system from the storm runoff - either pre-treatment, downturn on inlet pipe in manhole, perforated pipe with slots on the top half of the pipe only, means to flush out the perforated pipe etc)
