There was a huge emergency presence this afternoon as police helicopters and paramedics were spotted.
Emergency vehicles were parked up near the World of Water site by Hunton Bridge roundabout from around lunchtime until the early afternoon today.
UPDATE: Police have now confirmed a woman died in this incident - more details here.
Hertfordshire Constabulary has yet to confirm what this response was for, but it is believed at least eight police cars, a police helicopter, four fire engines as well as ambulances and an incident response unit were present.
It is understood that the helicopter was at the scene until around 1.45pm.
Police were also seen searching for something near the River Gade in Bridge Road, Hunton Bridge.
While specifics on the search are unclear, the Watford Observer understands that the searches conducted were related to the river.
It appears the search has since stood down and we expect further information to come from police by tomorrow.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here