Diamond Valley Lake Saturday April 29th, 2017. While the primary purpose of Diamond Valley Lake and Lake Skinner is to ensure reliable supplies of high-quality water for southern California, recreation opportunities for the public can be made compatible with operation of these lakes. However, Metropolitan reserves the right to suspend any and all boating and other recreational activities for water quality, operational or any other reason. To protect water quality and guard the health and safety of the boating public, Metropolitan has established the following non-body-contact boating rules for all watercraft at both DVL and Lake Skinner as shown below. Diamond Valley Lake is famous for its bass fishing. The lake is home to both largemouth and smallmouth bass, stripers, rainbow trout, bluegill, sunfish, catfish, and carp. All anglers must purchase a $3 Fishing Access Permit. Smallmouth bass are catch and release.