TWIN FALLS, Idaho (KLIX) People wanting to go for a dip or go fishing at the popular Dierkes Lake will have to wait a while longer as city officials determine the cause of a color change that happened before the weekend. On Friday the city of Twin Falls issued a notice that access to Dierkes Lake and the Hidden Lakes would be closed while the water is being tested for safety after the color of the water changed to an apparent bright green. Access to Shoshone Falls Park is still open. The city advised people not to swim, fish or recreate at the lake until test come back later this week.