This past weekend I learned that the entire upper 2.5 mile segment of the Riverplace Nature Trail has been closed by the city of Austin. This runs from the Panther Hollow Intersection north.
This closing entirely affects the Solar System series and the Rainbow series as well as individual caches along that trail segment. Those caches are entirely unavailable at this time.
This picture shows the sign just north (up trail) from the Intersection (at the .5 mile marker). The trail is now closed all the way from this point to the north trail head or 2.5 miles of trail.
To be specific, the following caches are now inaccessible (first two being series of 7 and 10 additional caches):