Tyler McQuarrie, from Watford, is behind bars following the assault on an officer in Maple Cross.
Fire crews were called after a package started leaking fluid.
Police have reopened the M25 in Hertfordshire but drivers are being warned to expect lengthy delays.
A nearby resident says the fuel in the stream "stank" and the spill left her "alarmed, upset and worried".
A HS2 spokesperson says agreed noise levels "have not been exceeded" and no rules are being broken.
Ronald Ruddock, 60, knocked the motorcyclist into the path of a lorry, court hears.
The RAC estimates 19.5 million road trips over the break with traffic likely to be worst on Friday.
An investigation begins after a fire in a tunnel being dug for the new high-speed rail line.
Councillors and an elected mayor are standing in Hertfordshire on 5 May.
