The 3-4 inches mentioned here is probably still accurate:
Y MagazineGrass for the Gridiron 28- year-old turf was removed from BYU’s LaVell Edwards Stadium over the summer. 11- inch gain in elevation from the sidelines to midfield on the old field; the crown raises only 3.5–4 inches on the new field. 12.75 inches of sod, sand, and gravel layered beneath the...
https://magazine.byu.edu/article/in-sum/