Project Description

Kaho'olawe is sometimes called 'The Wounded Island' because it is, literally and figuratively, wounded. Kaho'olawe now loses an estimated two million tons of soil each year to erosion. For an island that's only about 30,000 acres, that's a lot of soil. Here are some of the reasons why this happened, and what our group is hoping to do to help heal the island.

Goats

The insults to the island's ecology started when Captain Cook made a gift of goats to Maui's King Kahekili in 1793. For the next two centuries these goats were left to run wild and eat, eat, eat. By the 20th century, there were approximately 50,000 goats on the island, competing for every leaf and blade of grass. The island was stripped of its vegetation, and the topsoil was exposed to the island's intense winds and rainstorms. One website puts it as well as anybody: "How do you make a desert? Take any piece of land. Add goats." 

Guns
In 1941, following the Japanese attack on Pearl Harbor, the US Navy needed a handy place for target practice. Kaho'olawe was commandeered and for the next 49 years it was used as a bombing range. The island absorbed just about every type of exploding object imaginable, short of nuclear weapons. In 1965, the navy conducted a "nuclear simulation" blast by blowing up 500 tons of TNT on Kaho'olawe's western shore. The crater from that blast is visible from space. Unfortunately, the goats survived.

TNT mound before Sailor Hat explosion

Video of the test is available here.

In 1990, President George H.W. Bush ordered the navy to stop bombing the island. The goats were eradicated soon after, but the damage was done. After a brief, underfunded cleanup effort, the island is still peppered with unexploded weapons. It is assumed that the bombardment helped to dislodge otherwise stable soil and accelerate the erosion that the goats started. The real legacy of the weapons testing is that it makes moving around the island (and sticking things like scientific instruments in the ground) extremely dangerous.

Our Project - Some Context
First off, we should mention that our project is one of many on Kaho'olawe, and is by no means the most important one. There is a long-term restoration plan in place, and we are hoping to help with a small fraction of it. Unfortunately, the plan has no long-term funding, so the Kaho'olawe Island Reserve Commission (KIRC, which oversees the island) relies heavily on volunteers like us. We approached the commission in late 2010 and offered our expertise. On June 24, 2011, the KIRC officially accepted our project and offered support us to the best of its ability. Field work is scheduled for this fall.

Water, Water Everywhere...
Despite being surrounded by the vast Pacific Ocean, there is no surface water on Kaho'olawe: no lakes, no ponds, no streams, no springs and no rivers. During the wet season water does pool up in certain areas but the vast majority of rain just runs off, taking valuable topsoil with it and continuing the cycle of erosion. This part of the story is described a little bit in the first blog entry.

One of the issues with Kaho'olawe's rainfall is that it is sporadic and intense. In other words, when it rains, it pours. And then it's dry for six months. And then it pours again. As you can imagine, this makes for a tough life if you're a plant. Replanting efforts are underway (as a means of stabilizing soil and reintroducing native species), but it is a challenge to keep these plants alive. The only source of irrigation water on the island is a one-acre building designed to trap these intense rains. While that's a start, there is still an extreme shortage of water for maintaining the new plants. In any other part of the world we'd solve this problem by doing something we've been doing for thousands of years: dig a well. However, there are two problems with digging a well on Kaho'olawe. The first is that nobody is sure there's fresh water there to dig for. The second has to do with the island's history as a bombing range: long pointy metal things forced into the island's surface may just go boom.

We're not experts on unexploded ordnance. The KIRC has those. But together, we're a team that specializes in using low-impact, non-intrusive techniques to understand groundwater systems. In short, if there's fresh water somewhere beneath the island's surface, we're the ones that should be able to say where it is, why it's there, and what might happen if you mess with it.

The plan is to build a 3-D groundwater model of Kaho'olawe. While it won't be a perfect picture of the island, a model will help us to understand the system and visualize some of the processes at work. Before this can be done, though, we need some idea of what types of geologic structures exist and where, if anywhere, fresh water lies below the surface. Enter Dr. Lee Slater and Dr. Kristina Keating, specialists in near-surface geophysics from Rutgers University's Department of Earth and Environmental Sciences. Drs. Slater and Keating will provide expertise and equipment that will enable us to say - for sure - whether or not there is fresh water within 100 meters (330 feet) or so of the surface.

Dr. Jeffrey McKenzie and I, both from McGill University, will bring knowledge about the island's geologic history, as well as groundwater modeling skills. We will also be using temperature differences between groundwater and ocean water to look for fresh water that might be 'leaking' out of the island into the ocean.

To see the full proposal we submitted to the KIRC, which includes an executive summary and a detailed project description, click here.