Mold Remediation - Water on top of the crawlspace liner with scum

Here's a picture of a longstanding puddle of scummy water found near the crawlspace window vent.  Water on top of an existing liner means that the crawlspace is not just suffering from groundwater intrusion, but is also seeing water come in from the concrete block walls, so just lining the floor is not adequate.  Covering outside vents, dehumidifying the environment, and possibly lining the walls are also necessary to keep this crawlspace dry.