The west end of Moloka'i is notorious for plumes of mud that bleed into the nearshore waters after rains.

One traditional story is that the West End grew arid in a conflict between supernatural siblings — a brother who made rain whenever his sister tried to dry kapa, and the sister who overcame his power and turned the region arid.

Another story is that the dryness got worse when native forest disappeared during early sheep ranching, and that erosion was promoted by the appearance of other hooved herbivores — notably cattle and deer.

Wherever the blame lies, it seems clear that, without help, much of west Moloka'i lacks the rainfall needed to revegetate itself on slopes now so badly eroded that there is little topsoil left — and on which cattle and deer still roam.

A proposed residential development by Moloka'i Properties at the southwestern corner of the island, at La'au, proposes to address this problem, at least within the confines of the development.

Among the recommendations in a draft environmental impact statement on the project are the revegetation for erosion control of barren slopes near the shoreline. There would also be fencing to keep deer and cattle off the revegetated land.

Any new developments like roofs and roads that shed water — increasing potential overall runoff — would be required to retain that water in detention ponds or other containment systems, or would be required to remove the silt from the runoff before allowing it to flow to the sea.

To minimize the impact of human use on the nearshore reef communities, the development would also strictly regulate fertilizer and pesticide use.

Without taking a position one way or another on the appropriateness of the La'au development, the proposals are ones that deserve statewide attention.

It just seems like a good idea to ask landowners to vegetate bare areas that dump sediment into streams and to minimize or control activities that tend to promote erosion, to establish water retention structures, and to limit the flow of chemicals into storm drains, streams and ultimately the shore.

In urban areas, the eroded area might be a dusty, inadequately maintained ball field. The chemicals might be from auto oil changes and household cleaners. Oh, and those water retention structures? In the absence of humans, they often form naturally as coastal wetlands. They have a lot of functions, but one is to filter out land-based sediment from runoff.

If you have a question or concern about the Hawaiian environment, drop a note to Jan TenBruggencate at P.O. Box 524, Lihu'e, HI 96766 or jant@honoluluadvertiser.com. Or call him at (808) 245-3074.