Basically, this mod cross-patches Water for ENB (Shades of Skyrim version) and Lux and also provides the following tweaks:
Markarth Lods are UNLOCKED similar Markarth LOD Unlock but compatible with FWMF
Removed grass from several worldspaces such as Windhelm, Riften, Solitude and various caves - this should improve stability AND FPS with no visual downgrade.
Load this file LAST in your load order. After EVERYTHING else.
Redundant Mods (this mod incorporates these things + more *note you should use mechanicalpanda's patch if not using W4ENB):
Markarth LOD Unlock
LUX - No grass in interiors - Flat Worldmap Framework patch UPDATED
Riften City Grass Remover - FPS fix