[WIP] Ring of Fire

Hello, this is my first attempt using UE4 so i thought if i do a WIP thread i could get some valuable feedback as i learn the ropes.
About the map
This is an island map based upon an ancient asteroid impact crater.(a slightly raised atoll) There will be a rather large flat coastal region to the south where all players will spawn and it comprises of basic resources, docile wildlife, serene lakes and forests. The central part of the island is encircled with jagged, volcanic mountain ranges and will host a vicious environment, including drastic temperatures, super aggressive wildlife, dark quarries, tar pits, lava lakes and a snowy plateau. There are a few secluded beaches dotted around the more northerly coasts.

The idea for the map is to attract certain activities to certain parts of the map. For example, more PVE orientated players will likely remain in the tranquility of the south or even the other secluded coasts. Often planning dangerous treks to parts of the island they may require different resources. However, PvP players would naturally settle close to desirable resources in the central region.
The resource distribution will be different to the main game as it will be located in only a few regions. I will be creating massive forests but split between huge plains with very few trees, this will create a need to move around the map and a need to use pack mules. The forests will likley not contain metal rocks but there will be deep quarries that will produce abundant metal and stone. I will be adding (or trying) tar pits that will yield oil. The dino spawns will be region locked mostly. For example, Mammoths can be only found on the freezing plateaus, sabres will be prowling the mountain passes, Brontos will stride the plains and argents can only be found atop mountains. Again the idea is to create a feel of planning your next move (going to tame a mammoth? you may need to make some appropriate food, clothing, etc. Desparate for metal? be prepared for the heat of the quarry and the threat of other players!
I understand the ARK official map sort of concentrates certain resources, but i am going to really separate them to add more travel, which leads to more player encounters. A big let down for the official map was, you could build a base anywhere, walk out your door and anything you wanted was right there.

It is going really well so far, i have been able to add everything i wanted. I pretty certain i will run into problems sooner than later though ha.

Here are some screens but i have literally just started today, i will update as i go.

WIP_ROF1.png WIP_ROF2.png WIP_ROF3.png

I do have 1 annoying problem, if you can notice a tide mark type line running near the water line. I cannot get rid of this, any idea what it is?