The northern Hawaiian coast

Geographic regions of the Big Island. Map source

The northwestern district of Kohala and the Hamakua coast were among the final regions we visited while making a loop around the Big Island. Like Kau to the south, these areas less populated than the Kona and Hilo coasts, scattered only with small towns, farms, and impressive vistas of open space. There are a series of green valleys sculpted into the northeast-facing coast of Hamakua, largely inaccessible except by hiking.

From the North Kohala side, at the terminus of state road 270, is Pololu Valley. It appeared to have an estuary of sorts, with a sediment-laden chocolate stream that wound back into the valley. The mouth of the stream had a shallow connection to the ocean because of the buildup of large cobbles on the beach. Visible to the east were cliffs and a few offshore islets. The wind was strong here, stirring up numerous white caps out at sea. To me, the whole scene was reminiscent of portions of central California in some degree, like the rough coastal gem of the Big Sur area. 

The northwest coast of Hamakua from the overlook
above Waipio Valley. A waterfall nearly reaches
the beach.

Waipio Valley is also among this chain of coastal valleys. The valley used to be a prosperous settlement, both during Polynesian rule of the Hawaiian Islands and more recently. Hawaiians referred to it as the ‘Valley of the Kings’ (Barth 1995). A devastating tsunami in 1946 obliterated the area, and resettlement has been sparse. From Waipio Valley, there is a trail that heads northwest to the next coastal valley (Waimanu Valley) which would be a treat to backpack some day.

Down in Pololu Valley, the shore was rough with wind, waves, and a beach covered in cobbles of lava rock worn smooth by the surf. There also was a significant amount of debris – bottles, fishing buoys, decaying buckets. These items may have traveled thousands of miles to land on the shores of Hawaii. With some help from the kids, we gathered up a number of items to remove them from the beach.

Pollution is a distinctly visible reminder of humankind’s impact to our most cherished natural areas. It is particularly unwelcome on our beautiful coastlines. Yet, visibility aside, it is probably one of the lesser human impacts to the oceans. Habitat destruction, overfishing (which disrupts entire food webs), and changing climate are perhaps more pernicious threats to ocean biodiversity and function.

Pololu Valley.

A black cobble beach at Pololu Valley and the cliffs of the Hamakua coast in the distance.

Flying for hours over the vast Pacific, the immensity of the global ocean is made apparent. Individually, we are barely specks on this immense globe, so it is perhaps natural to assume that our species can have little impact on this globe. Yet evidence from every line of science points otherwise. When tsumani debris bearing living organisms arrives on the shores of Oregon from Japan (as I was able to observe firsthand a few years ago), it becomes apparent just how close supposed distant places are to each other. Our collective human impacts on our planet have become pervasive.

The kids helped gather marine debris washed ashore at Pololu Valley.

Coastal topography near Pololu Valley, from 1995 USGS topographic map, Honokane, HI.

Reference

Barth S. 1995. The Smithsonian Guides to Natural America. The Pacific. Smithsonian Books, Washington D.C.