Shakey Graves performs at the Austin Music Awards. Jay Janner/American-Statesman.

Wednesday’s Blues on the Green concert at Zilker Park featuring Shakey Graves and Riders Against the Storm has been postponed until Aug. 12 due to City of Austin Parks & Recreation concerns about the condition of the park grounds following recent rains, sponsoring station KGSR reported.

It’s the second postponement of the season for the popular free concert series, after the season-opening Antone’s 40th Anniversary Celebration was delayed a week in the wake of the Memorial Day floods. Around 20,000 turned out for the June 3 rescheduled date with special guest Steve Miller.

The rest of the Blues on the Green season is now scheduled as follows: July 22, Bob Schneider and Walker Lukens; Aug. 5, Jamestown Revival and Kaleo; Aug. 12, Shakey Graves and Riders Against the Storm. More details on the series are at kgsr.com.

Standing water and muddy grounds in many areas of the park after rains over the past few days resulted in the city’s decision to postpone. KGSR shared the following photos from the park, taken this morning:

Zilker Park on Tuesday morning, June 23, 2015. Photos courtesy KGSR