Pictured here is a grate over Crippled Crawfish Cave in Onion Creek taken on 4/12/12. This cave and other small solution cavities in the creek are recharging all water that is flowing onto the recharge zone of the Edwards Aquifer, which is about 35 cubic feet per second. Note the small whirlpool in the lower right corner of the photo. Streamflow is diminishing quickly and soon recharge will cease altogether. Hopefully more rains will come this spring to continue the streamflow and recharge into features such as these.
This feature, and others, are on lands owned and operated by the City of Austin for the sole purpose of water quality protection and restoration. A dye trace study in 2005 demonstrated flow from this feature to wells and Barton Springs. The dye arrived at Barton Springs is about 3 days at distance of about 18 miles!