Does anyone have any insight to the granting of easements and possible compensation?

We live on a 27 acre property which has an existing 30 foot easement on one end of the property. The county has hired (I assume?) a nonprofit water authority to run city water and sewer access to a subdivision. This apparently requires a 50 foot easement--20 more feet than they currently have, which equates to about an additional .75 acres of our property. The engineering company actually didn't realize that they didn't have the required 50 foot easement until my husband pointed it out, and now the woman we are dealing with at the water authority is being a real b*tch and basically trying to bully us into giving the easement. She said that they have never offered monetary compensation for easements, and has only offered us hookups to their system (which we are not interested in as we have three water wells and a septic system)

Sorry for the long winded description. We don't want to hold their project up but we also don't want to just give up .75 acres of our property just to be nice. [note: it wouldn't just be buried lines, there would be mounds and manhole covers that would forever alter the landscape of our property].

Anyone have any insight? We're having trouble finding resources online about compensation for scenarios like this.