How to encourage quality content in small populations?

I'm creating an app that allows users to post content onto the app for other community members to use. The content is forever changing IE, eventually the content posted by a user will be deleted and replaced. It's an on going cycle that requires some dedicated users to participate in posting accurate content. I can not moderate the content because I can't verify it to be true. (only those who live locally can can attest to it's accuracy)

Because the content changes the responsibility of creating AND deleting content is at the disposal of all my users which I can imagine is very dangerous. The content itself is not sensitive or important by any means but having accurate information is crucial to the success of the app. To make it even more challenging the user base for a particular location may only be a handful of people. A guess would be around 10 - 500 users per location.

User generated content (UGC) has become common place in apps and websites (Youtube, StackExchange, Wikipedia, Forums) however I believe my app differs in 3 important ways from most other examples. Firstly with small apps/websites the creator can monitor all the activity, Secondly in large communities the community can vote on or promote content/users that they like. Thirdly, the content has a "right" answer unlike the UGC of YouTube.

To summarize

  1. The UGC must be accurate for the app to succeed
  2. Only users in the same location can verify the accuracy of UGC
  3. The user base for each location is small
  4. The content must regularly be replaced

Can anyone point to examples of apps or websites that are similar in nature to mine? Or does anyone have any suggestions on how I can promote accurate content given these restrictions.