Neighbor's trees killed my evergreens

[KentuckyGuy]

What is the name of your state (only U.S. law)? KY

I have a neighbor that ran a down spout drain line from his house, along a fence and the water drained onto my property. I own about 40 large arbor vitaes along my property line that are planted 10 feet from the edge of my property. My neighbor has some very large trees that are extremely dense and have never been trimmed.
His very large trees blocked the sun on about 4 of my arbor vitaes killing them on the shaded side.
As a result of his water drainage and his trees killing one half of my arbor vitaes, the arbor vitaes are now leaning about 45 degrees as one side of the root ball has pulled out of the ground. I have asked him to do the right thing (replace my trees), but he thinks it is my problem.
This is the same guy who borrowed a 32 foot ladder, dropped it and bent it. He denies doing this, but he is the only one besides me that used it. He also put a gas line through part of my yard.
Any advice on the half dead arbor vitaes?

 

[justalayman]

you have a valid claim for provable damages the water caused. You have no claim to damages from them being shaded by his trees.

If you are aware of a problem, you to have a duty to mitigate (minimize) your damages. If you failed to do so you will not be due damage subsequent to that time. I'm not saying there was anything you could do but there often is. Notifying the neighbor of the problem when it was discovered his water was washing out your root balls would be one effort of mitigating your damages. Making some attempt to divert the water would be another.

 

[csi7]

The neighbor is responsible to repair the storm drain to drain in his property. If he did the gas line illegally, it can be forced to be moved. I'm surprised a property survey was not required prior to gas line being put in.
As far as the trees, the damage from the drainage of the water, the neighbor is responsible for.