Police were called at around 11.15am today by a member of the public who had found the body in the water near Tinkers Lane.
A third worker has been arrested by Essex Police as part of a probe into a Braintree care home.
The woman, in her 50s, was arrested at her home in the Braintree area on suspicion of assaulting a resident at the Old Deanery Care Home.
The home came under the spotlight after an undercover Panorama investigation captured alleged abuse during filming last year.
Broadcast on April 30 it has prompted a police investigation.
The woman has been released on police bail until the end of July pending further enquiries.
Earlier this month two women aged in their 30s and 40s were arrested at their homes, also in Braintree, on suspicion of assault. They are also on police bail until the end of July.
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