Don Miller, a New Zealander who works in the south Pacific, has, over a number of years, been working with local people to reforest a particularly badly eroded area near Port Patrick. The result has been spectacular. A modified power point can be found at TVNI's website (see http://www.vetiver.org/VAN_REEF/VAN-reef2.htm).
In my travels around the world I have seen many instances of coastal waters turned brown by sediment flows. If you don't travel take a look at Google Earth images of Hawaii, Fiji, Jamaica, Honduras, Indonesian islands, and many more.
The Vetiver System is the best and cheapest and greenest way of dealing with the problem. In addition to preventing sediment flows to the sea it reduces sewage and other pollutants reaching pristine beaches, improves groundwater (reduced ground water on many islands is becoming a major problem), improves crop yields and provides bi-products in the form of biomass for fuel, forage and handicrafts. The Vetiver System is available to anyone who wishes to use it, and if applied correctly it will work.