Beach access at Marina Park re-opened to the public Tuesday following a wastewater overflow from the Kirkland Pump Station on Thursday. The incident kept the beach closed as temperatures hit record highs during the weekend.

The red closure signs that dotted the shoreline were removed with the approval of Public Health – Seattle & King County when laboratory tests showed water quality to again be safe for swimming and wading. One closure sign will remain at the pier as a precaution pending additional laboratory sample results.

King County staff posted the beach as closed as a precautionary measure to protect public health when the 60-minute overflow sent an estimated 68,000 gallons of wastewater into the lake through an emergency outfall, which prevented sewage backups in homes and businesses. The station’s average pumping capacity is about 5.6 million gallons a day.

The overflow was caused by an unusual combination of circumstances when a transmitter signal failed to engage two of the station’s pumps. The clutch failed on a third pump that normally engages when station water levels rise. The overflow was discovered during daily monitoring and maintenance of the station.

County staff notified the public as well as health and regulatory agencies about the overflow.

The Kirkland Pump Station has been operating for more than 40 years. King County is investing a total of $20 million in a project to increase the station’s pumping capacity, replace aging equipment, and install new, larger diameter pipes. The new station will begin operating in November 2013, with project completion scheduled for early 2014.