Overhappiness
Population gain is increased when a swamps happiness goes above 100 happiness.
If you team up with a big swamp and they donate you large quantities of money, Project rate can be used to grow your population at crazy speeds. This can allow small swamps to catch up quickly.
At the end of the tick your happiness will be capped back to 100
doubles population growth for each happiness point over 100. 0.12% population gain per point instead of the usual 0.06% population gain per point.