The Hawai'i That Was: Where are the Rivers? Waterfalls on the Big Island

Tooling around on the southern parts of the Big Island of Hawai'i, one may notice something. Despite the fact that Hilo and the Puna District villages get more rain than any other towns in the United States, there aren't very many rivers. The area is a rainforest, but there are hardly any areas of open water. In fact, a drive around the most of the island, say from Hawi on the north end through Kailua-Kona, around South Point and along the slopes of Mauna Loa and Kilauea, I can't recall seeing a single flow of water. There are a number of reasons. For one, some areas lie in the rain shadow of the big volcanoes. The area north of Kona is practically a desert. On the slopes of Mauna Loa and Kilauea, the reason has to do with the volcanoes themselves.

Wailuku River from the top of Rainbow Falls

Basalt lava, the product of Hawai'i's volcanoes, is not a particularly permeable rock. There might be vesicles (gas bubbles) that can allow water to move through, but by and large basalt is solid and impermeable. Except when it cools. The rock contracts and shrinks, forming joints and fractures. These cracks provide avenues for water to sink into the ground. There might be plenty of water, but it flows through subterranean fissures, not on the surface. It might re-emerge along the coastline as springs, but in some cases the water flows into the ocean beneath sea level. There are places along the south coast of the Big Island where the only fresh water could be collected by the original Hawaiians by diving beneath the surf with water containers.

Rainbow Falls in Hilo,

The longest river in the Hawaiian Islands is the Wailuku, which runs for 28 miles mostly along the boundary between the lavas of Mauna Kea and Mauna Loa, then flowing into Hilo Bay. Although large volumes of water disappear underground, the path of the river partly follows much older Mauna Kea lavas that have weathered and form soil and clay that are more impermeable, keeping the water at the surface. In places, erosion has broken through to breccias and cinder layers that are more easily eroded, undercutting the lava flows. In this way, some beautiful waterfalls have formed. The most famous is undoubtedly Rainbow Falls (above), given the location near downtown Hilo.

The falls, known in the Hawaiian language as Waianuenue, are steeped in mythology. Stories have grown around the prominent cave behind the falls. It was the abode of Hina, the mother of Maui, the god who created the islands by tricking his brothers into pulling up part of the seafloor, thinking they were hauling in giant fish. A lizard-like monster called Mo`o Kuna kept threatening Hina by sending floods and debris down the river (floods are a common occurrence along the river). Maui came to the aid of his mother, defeating Mo'o Kuna and sending his carcass down the river.

Pe'epe'e Falls on the Wailuku River upstream of Hilo

Pe'epe'e Falls are a short distance upstream, and Wai'ale Falls can be seen a bit further up. Wai'ale tends to have the greater volume as water seeps into the ground downstream.

Wai'ale Falls on the Waikulu River near Hilo

On the Big Island of Hawai'i, the real world of waterfalls lies along the northeast coast between Hilo and the Polulu Valley. They occur on the flanks of Mauna Kea and Kohala, two of the older and mostly inactive volcanoes of the island. Some of the falls are world class in height, with at least one, Waihilau, falling 2,600 feet, which is actually taller than Yosemite Falls in California. I would love to regale you with stories of my adventures seeking out the giant falls in their remote valleys, but I haven't done that yet. We'll settle for a beautiful and accessible waterfall north of Hilo. It's called Akaka Falls, which drops about 420 feet. There is a short paved trail that provides a dramatic view.

This blog series, the Hawai'i That Was, is an exploration of the geology and anthropology of the islands, based loosely on our recently completed field course. I expect that the next post will be a bit sandy...and crawling with turtles. Stay tuned!

Random Nature Notes from Hawai'i: The Land Reptiles of the Big Island

Reptiles (aside from sea turtles) are probably not native to the Hawaiian Islands but there are quite a few of them on the islands today. Some were brought by the original Polynesian settlers (four species of Geckos). Others arrived as escaped pets. In any case, they have become a part of the native ecosystem for better or worse. Some help to control pests, for instance, and are welcomed in homes on the islands, but others have an appetite for the endangered native species of insects and other invertebrates.

They are undeniably colorful parts of the environment, and I've been enjoying capturing pictures of them this week. The picture at the top was a Gold Dust Day Gecko at Pu'uhonoa O Honaunau National Historical Park on the Big Island. The second was waiting for a meal at Akaka Falls State Park this afternoon.

The Jackson's Chameleon was also hanging around the trail at Akaka Falls. I believe it is the first one I've ever photographed. It seems to be laughing in the picture below, which causes me to wonder why, unlike geckos who sell insurance, they make bad comedians. I think it's because they keep changing their punchlines...

Here is a short video of a gecko going about it's business at Akaka Falls.

Aberrations of Nature: A Morality Play and New Meme

There's a new meme in town, started by Outside the Interzone concerning waterfalls we have visited. Like 100 places, it asks of us which waterfalls we have seen, in this case from a North American perspective. The list is as follows, and I'm even going to tell you which ones I have seen, but I have more to say at the end....

#10 Lower Calf Creek Falls, Escalante National Monument, Utah (A wonderful sight in the center of one of our country's most spectacular national monuments)

#9 Lower Falls of the Yellowstone River, Yellowstone National Park, Wyoming (A simply spectacular sight from any angle; from the very brink is absolutely mesmerizing)

#8 Upper Whitewater Falls, in southwestern North Carolina (haven't been to NC yet

#7 Snoqualmie Falls, between Snoqualmie and Fall City, Washington (Nope, not yet)

#6 Havasu Falls, Supai Village, Havasupai Indian Reservation, Grand Canyon, Arizona (Not yet, it's on my bucket list)

#5 Shoshone Falls, Twin Falls, Idaho (A spectacular waterfall, but often "turned off" as the river is diverted for irrigation. I got to see it in pre-digital-photography days)

#4 Multnomah Falls, Columbia River Gorge, Oregon (I visited this one as a child, but I was highly impressed at the time and still remember it well)

#3 Bridalveil Fall, Yosemite National Park, California (One of many spectacular falls in one incredible place; if you follow my blog you know I spend a lot of time here)

#2 McWay Falls in Julia Pfeiffer Burns State Park, Big Sur, California (This is one of the most beautiful waterfalls in existence, falling as it does right into the sea, which is one of only two in all of California. If you only follow one link on this post, check out this incredible view)

#1 Niagara Falls, Niagara, New York (nope, not yet, so I never know what anyone is saying when they say "it's twice as high as Niagra")

Waterfalls are an aberration of nature, a temporary interruption in the regular scheme of things, if we are to accept the models of the geomorphologists. Waterfalls don't get much respect from us geologists it seems, since a brief review of the relevant chapters of my textbook reveals little about waterfalls, except as decoration for the chapter cover photos. The chapters I looked at had literally no mention of waterfalls except as deviations from a graded condition.

"Graded"? Rivers adjust their channels in such a way as to remove irregularities by eroding "knickpoints" or depositing sediment within depressions. Following the dictates of physics and gravity, rivers are constantly approaching, but never quite achieving, a graded condition, in which no unusual areas of erosion or deposition exist. Waterfalls are the ultimate deviation, and rivers work furiously over time to remove them. As such, waterfalls truly are temporary, and we are privileged to see the ones that do exist.

This idea of approaching an "ideal" state sounds vaguely like a Victorian morality play in which we as humans seek, but never quite reach, some model of perfection. Scriptural passages speak of the inability of humans to reach a sin-free state without supernatural intervention or grace, and other passages talk of how the mountains will be laid low and the paths made straight. It sounds just like a river adjusting the channel it flows through....

Waterfalls ARE aberrations, and ultimately there is some kind of interesting explanation for why a particular waterfall exists. The river crosses a particularly hard exposure of rock, like a lava flow; glaciers have carved a deep gorge where tributary canyons cannot keep up; water falls off the edge of a plateau with a prominent caprock; a fault has lifted part of a river-course; a landslide has changed the canyon a river flows through.

Part of the waterfall meme allows that we can add one of our favorites; I offer four:

The first photo is Mealt Falls on the Isle of Skye in Scotland. It may be my favorite waterfall on the planet although I have only seen it once and from only one view point. Like McWay Falls at Big Sur, it essentially falls into the ocean. The seacliffs are composed of columnar-jointed basalt flows related to the splitting of Pangea and the opening of the Atlantic Ocean in late Mesozoic time.

The second photo is Akaka Falls on the Big Island of Hawaii. There are hundreds of incredible waterfalls on the Hawaiian Islands, but relatively few on the Big Island, and none as tall as this one, at 442 feet.

The third fall has no name that I have been able to find. I saw it near the town of Bellinzona in the Italian/Swiss Alps, and it left me breathless. It's also my favorite picture of a church!

The final photo is in no way an exciting or particularly beautiful waterfall, and it is only 20 feet tall. It's uniqueness is in the location: in the middle of the hottest, driest desert in the United States. It is called Darwin Falls, and can be found in a remote canyon leading into the Panamint Valley within Death Valley National Park. Somehow the waterfall feels all the more precious, and it is a vital permanent water supply for wildlife from miles around.

Have you got a favorite waterfall? Join the meme! If you feel that waterfalls were under-represented in the 100 places meme of a few months ago, you are also invited to make a contribution to this month's Accretionary Wedge Blog Carnival! Submissions due in a few days!