Mysterious sediment washed into the Chichester canal basin appears to have come from a storm drain in the city, the Environment Agency has said.
The silt appeared in the basin a number of times over a two-week period, causing residents concern as to what it was.
Senior environment officer at the EA Rowan Casebow said: “We received calls from members of the public witnessing silt-like material in Chichester Canal Basin and an Environment Agency officer immediately responded by visiting the site.
“The source was traced to a construction site adjacent to Exton Road where a storm drain had been discharging surface water with a high silt content.
“Suspended solids, such as silt, can damage fish spawning grounds and cause harm to gills, as well as decreasing the amount of oxygen in the water.
“Our environment officer advised the construction manager to install a silt trap, which filters out silt from surface water, before making any further discharge.
“The construction manager co-operated immediately and we are happy that the canal is now free from any sediment.”
Persimmon Homes South Coast is developing land adjacent to Exton Road.
Construction director at the company Stephen Bennett said: “The visit confirmed that any silt was not a result of the drainage diversion works we have at The Hawthorns and, as such, no further action was required by ourselves.
“The visiting officer also advised that the silt control measures, such as silt control filters and interceptors, we have in place are satisfactory and are working effectively to our environmental management plan for the development.”