sentences:  In April 1981, swimming in the park was banned when several elementary school children complained of cramps and nausea after swimming in Onion Creek.Testing indicated the fecal coliform count in the water was 2600 per 100 milliliters of water, well above the 200 count maximum deemed safe for swimming.The problem was blamed on rain water runoff from the mostly urban area located upstream on Onion and Williamson Creeks.