Hey Mike,
I wonder if you could install some storm wattle (fiber log) along the logging road to reduce the sediment runoff. Although I'm just a bean counter I work with several large trenching & grading contractors in California. They use storm wattle (aka fiber log) along graded areas to reduce silt runoff. Here is a link to a product to give you an example of what I'm talking about.
http://www.bascousa.com/store/item.aspx?DEPARTMENT_ID=157&ITEM_ID=973 I don't have any affiliation with the company or product and don't know for certain that it would be appropriate for your application but I just thought I'd mention it. Maybe if you installed it along the logging road or between your pond and the road it would help cut down the silt runoff. If you do an internet search on "storm wattle" you will get a bunch of info.
I know it wouldn't help your current situation but might slow down the silt runoff in the future.
