Have you ever noticed how fast an urban boat harbor, such as O`ahu's Ala Wai, can become very visibly polluted?

All it takes is one quick tropical downpour and suddenly, all of its up-stream "tributaries" (storm drains from the surrounding streets) positively gush with water-borne refuse.

Within hours, the boats moored there are surrounded by trash-bergs, and like their iceberg namesakes, what you can see is only the tip of the problem.

The marina's waters quickly become a solution containing everything from pesticides to animal excrement. What was on the street or in the gutter, always finds its way into the harbor.

As avid users of the marina and the offshore waters, most boaters understand the health and ecological threat of such pollution and work to limit their own contribution to it.

Now, to make that job easier, the University of Hawaii's Sea Grant Program and School of Ocean and Earth Science have teamed with the state's departments of Health and Land and Natural Resources to produce a booklet entitled "Managing Boat Wastes - A Guide for Hawaii Boaters."

In just 19 pages, this new guide presents solid ideas on how boat owners can have the least harmful impact on the marine environment, while still enjoying and maintaining their vessels.

The guide begins with a list of safe alternatives to the usual products used for cleaning boats inside and out. For instance, vegetable- or citrus-based soaps are advised, instead of petroleum-based soaps and detergents.

Particularly on boats with inboard engines, an automatic bilge pump is one of the most likely sources of petroleum pollution. A section in the guide deals with that collect-all area of a boat, the bilge, and how to avoid accidental discharges.

Another source of potential pollution from a boat is the head sewage system. The guide defines the current federal regulations regarding heads and suggests how boaters can best conform to those regulations.

Because the majority of boats owned in Hawai`i are outboard-powered, the section of the guide dealing with minimizing fuel usage and eliminating spillage should certainly be of interest. These actions not only lower the boater's environmental impact, but lower the cost of boating as well.

Another section of the guide deals with what seems to be a growing problem with not only boaters, but vehicle owners: the proper disposal of lead-acid batteries. It points out that vendors are required by law to accept old batteries when a new one is purchased, so there should be no reason for this type of pollution to occur.

The dos and don'ts of handling marine debris are also addressed, along with a brief outline of the requirements of the international Marine Pollution Act which prohibits the disposal of plastics and restricts the disposal of most refuse in the ocean.

Boat maintenance is another topic in the guide under the heading of Paints/Varnishes/Epoxies/etc. Together with a separate section on solvents, several ideas are offered to reduce their total impact to the environment.

There is no question that if the boaters of Hawai`i read and follow the directions in this guide, they can be sure they are part of the solution and not a part of the problem.

The guide is available at all state harbor offices, or you can have one mailed to you by calling (808) 956-4410.