Property easement

The town where my mobile home resides has a sewer line running through the center of it (adjacent to 80% of the spaces in the 55 space park). The town needs to replace the line, which will cause considerable disruption to the tenants. There is no easement in place for the city to come in and do the work. The city has offered $1.00 as consideration for the easement, which seems to be a steal for them. Has anyone been in a similar situation, with the question being how to go about establihsing the value of the easement.