TVA Surveyors and Appraisers

Strangers, including engineers, arrive in a valley, surveying and calculating, which leads the local people to realize that their traditional way of life may be at risk. More strangers, government appraisers, come to offer to buy their farms, indicating a significant change is imminent.

What is the significance of the phrase 'doomed' in the context of the valley people's life?

What do the appraisers from the government offer to the valley people?