Water service at Ala Moana Regional Park will be shut down Monday to accommodate the city’s irrigation system upgrade for the complex.

That means no regular toilet, shower or drinking water service that day at Oahu’s most heavily used park. There will, however, be portable toilets placed near existing comfort stations throughout the park. No shower facilities will be available during the shutoff. Magic Island will be included in the shutdown as will the L&L Hawaiian Barbecue concession at the park.

The suspension of water service will allow contractor RMY Construction to make connections to the water supply at four locations in the park, the city Parks and Recreation Department said. The work is expected to last all day but service could be restored earlier if the upgrade is completed ahead of schedule.

The overall project is expected to be completed in the summer. Parks officials said the configuration of the current irrigation infrastructure comprises of a patchwork of separate systems that have undergone different levels of maintenance since the 1950s. As a result, it is not possible to isolate the four areas where the new connections are being made in order to limit the impact of a water shutdown, city officials said.

RMY won a $2.02 million contract for the irrigation improvement project, which includes installation of a Rain Bird Maxicom system designed to provide a more effective way of watering the park, parks officials said. The upgrade is expected to reduce water usage while extending plant life and minimizing maintenance needs.