The Conservation Commission Tuesday night requested additional information on a proposal to draw water from the Westfield River for a water feature installed as part of the state bridge construction project.
The city is seeking an order of conditions from the commission to operate three water cannons installed under the scenic overlook on the south bank of the river between the two bridges.
Each of the three cannons is designed to shoot about a thousand gallons of water per minute, spraying water back into the river.
City Engineer Mark Cressotti said that the discharge of the water cannons will be choreographed with the clock-tower display which can be program to occur every three hours.
The cannons will be recharged with water from the river between displays.
John Goddard, project manager and landscape architect with R. Levesque Associates, said the system will withdraw 3,000 gallons during the three-hour recharge process at a rate of 15 gallons per minute.
“A charge pump will draw water into a subterranean chamber over three hours,” Goddard said. “Then it will be discharged back into the river. Three high pressure pumps operate the water cannons.
Cressotti said the recharge system will have a six-inch pipe going out into the river and encased in riprap (stone) to protect the inflow pipe and pumps from debris. The system also will have screens to prevent fish and other fauna from being ingested into the pumps.
Commissioner Henry Bannish asked if there are other water cannon systems in the area.
“I’m interested in knowing if there were problems over time, if there was impact on the fishery and on endangered species, so I’d like to know where this system is being used and if there were issues,” Bannish said.
Commissioner Robert Natario asked if any part of the system is located in the river flood zone and if those structures would displace water.
Cressotti said the intake pipe will be installed “in a manner not to obstruct flood water.
“It will be placed at the bottom of the rock wall of the abutments to minimize the impact on the resource area in the river,” he said.
Cressotti said the water being discharged by the cannons will shot a third of the way across the river and the spray will be a “rain event’ as it reaches the surface of the river to prevent scoring and erosion.
“This is intended to be a destination, a draw choreographed with the clock tower during the proper seasons when the river flow is sufficient enough,” he said.
