Are they going to reconstruct it ?
These arches a bit different than anything else that the forestry protects.

Quantitative data and chances to determine the age of initial formation of an arch are actually quite rare. The best example we know is Rainbow Bridge, which formed as an entrenched meander bend in bedrock was punctured and cut off. Geologists have dated abandoned river terraces in the Glen Canyon region and used these to estimate rates of incision of the Colorado River. From these, the age of the initial puncture of the meander bend at Rainbow Bridge has been estimated to be about 30,000 years ago – this is reported by Chidsey et al. in Geology of Utah’s Parks and Monuments (2010). Obviously this is a very large natural bridge so not of comparable scale to Rainbow Arch, just one of the rare few examples where we have some data on the age of initial formation of a natural arch or bridge. Using Rainbow Bridge as a guide, and taking the large amount of debris under Rainbow Arch into consideration, it likely formed no more than a few thousand years ago and may have had its final shape for only a few decades prior to collapse