When you create a sand or pea gravel beach for swimming in a pond be prepared for a lot of work to keep it clean. All sorts of weeds will want to grow in the material above the water line. Underwater filamentous algae and submerged weeds will constantly want to invade the area. It will take chemicals or frequent manual labor to keep plant growth minimized.

The other big problem is what I discussed in one of the threads noted below - development of black anoxic sediments. The way beaches on lakes stay relatively clean is the periodic heavy, strong wave action thrashes the beach area to keep the upper layer oxygenated and fairly clean. This strong wave action does not happen in a pond thus the only prevention of the sand area from becoming black and anoxic is occasional mechanical mixing such as raking the beach area. Children frequently playing in the beach area also helps. Thus, keep the beach area no bigger than what you want to manually rake it 3-5 times a year. Development of anoxic sediments requires several years to develop buy when established, it is very labor intensive to rid the anoxic conditions.

Past Pond Boss discussions of building sand beaches
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=43085

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=260168&page=1

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=302736

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=222828

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=190416

Last edited by Bill Cody; 04/06/17 07:08 PM.
aka Pond Doctor & Dr. Perca Read Pond Boss Magazine -
America's Journal of Pond Management