responsibility for gate on easement

i sold a piece of property in washington state and included an easement for ingress egress and utilities. this easement connects to another piece of my property. stipulated in the easement discription was the requirement for a gate , which i built and installed. now after 10 years the owner of the property which has the easement wants the gate changed. (barb wire gap) i have no problem with this and built a new gate much nicer and fancier. after it was 90% complete he was not happy and wants to put a chain in place of the gap. my question is who has the legal right to build and design this gate...? thanks for any relevant opinions lance