'heavier impact' is correct and usable in written English.
It can be used when you want to emphasize the intensity or severity of an impact. For example: “The proposed policy changes will have a heavier impact on small businesses than on larger corporations.”.
With each generation, there is a heavier impact on the early-life microbiome.
Factor loadings showed that temperature presented heavier impact on k compared to the other factors.
Landscape heterogeneity increases as grazing unit size increases, resulting in heavier impact on preferred areas.
The reason for the heavier impact hinges on Medicaid, the joint state-federal health care program that covers nearly three million needy children in Texas.
Indeed, Fox's fast climb was clearly aided by the fact that its 2.5 hours of hit reality programming had a proportionately heavier impact on its schedule at 15 hours than it would have at 22 hours.
Since climate change has already affected forests in Central Europe and much heavier impact is anticipated in the future, the models should be applicable for prediction of future tree height development and able to quantify the impact of climate change.
Some pieces of circumstantial evidence had a heavy impact on the jury.
DuPont also showed the heavy impact that the rise in the price of oil was having.
In Thailand, they had such a heavy impact that a new local genre was born: Shadow Music".
Halts to production caused by the March 2011 earthquake and tsunami in northeastern Japan had an especially heavy impact on automakers.
The killing is substantially indiscriminate, with heavy impact on species already battered by destruction or fragmentation of their breeding habitat.
