Get website path ( in 3 layer applicaiton0

I am develping a website, which has n-layered application.
I have wrote error logging code in DAL and I am adding that dll to website(adding reference) and calling the write log function.
But how do I get the website path??
like if the code is written inside App_Code then we can write "Server.Mappath("~");
But in this case how i can write?
"Server.MapPth" is not working.....??


Please help!!!

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