PI: Water in Hawaii Volcanoes National Park

The Big Island of Hawaii is an island surrounded by the salty Pacific Ocean. Yet Hawaii is advertised as a tropical paradise. Thanks to the water cycle, the salt is left in the ocean and rain clouds regularly drench the islands with life-giving freshwater.

There are many different climates on the island and that means there are lots of different ecosystems—often based on the availability of water. In fact, you can find desert, mountain, and tropical vegetation within just a few miles of each other. About the only climate you will not find is a glacial one (though there is evidence glaciers were once found on the peaks). Snow gets fairly deep on the peaks but it does not stay around long enough to form a glacier.

Precipitation on the Big Island varies a lot. Some places on the island receive less than 1 foot of water while others get over 21 feet in a single year (the park varies from 1-8 feet). Overall, the

north- eastern part of the island is more humid (and rains more) than the southwestern part. The mountain peaks are by far the least humid places on the island.

Groundwater is the main source of drinking water (for both people and plants) on the island. Most precipitation quickly infiltrates the “holey” and fractured rocks of the island. In fact, even the streams and rivers are fed mainly by groundwater.. Sometimes groundwater leaves the surface in the form of steam. This happens when ground- water flows through hot volcanic rocks below the surface. If you get close to one of the vents where the steam is escaping you can actually hear a hissing sound similar to a teakettle boiling.

There are very few lakes on the island. But Big Island does have one of the highest natural lakes in the in the world (13,020 feet above sea level). Snowmelt and rainwater collect inside an old volcanic cone. Water does not easily infiltrate the rocks of the cone and water only escapes through evaporation.

While there are many streams on the island, very few actually flow through the national park. This is because the rock in the park is young. Rainfall infiltrates young rock (e.g. the peaks inside the park) too quickly for it to “pool up” at the surface. Rainfall infiltrates the older rock (e.g. the peaks outside the park) more slowly. Thus more water stays at the surface and can carve out impressive landforms like waterfalls. The water that flows over the falls brings sediment and deposits it along the riverbanks. The falls are also places where the water is dramatically eroding the land. You would find the rocks of the falls very smooth if you were to touch them.

Bamboo Forest – The northeastern side of the island supports rainforest. One does not

have to travel far to be in an entirely different climate on the island.

Steam Vents – When groundwater flows closely to recently formed rock or

molten rock, it will change into vapor and move into the atmosphere.

Lake Waiau – This is one of the few lakes on the island. Water flows into the center of the crater and the rocks do not

allow much water to infiltrate. Evaporation is the big control on the

lake level.

The water in the streams, rivers, and groundwater that doesn’t evaporate or get consumed by plants and animals flows directly into the ocean. Even the ocean dramatically shapes the land. The constant waves break apart and smooth recently formed igneous rock. This is why the sandy beaches take on such different colors. Beaches on Big Island are made up of white (from ocean coral), black (from island rocks), or even green sand (from island rocks). The sand is the color of the sediments that are weathered and deposited on the coastline. In the national park most of the beaches are made up of black sand. The water in the streams, rivers, and groundwater that does not evaporate or get consumed by plants and animals flows directly into the ocean. Even the ocean dramatically shapes the land. The constant waves break apart and smooth recently formed igneous rock. This is why the sandy beaches take on such different colors. Beaches on Big Island are made up of white (from ocean coral), black (from island rocks), or even

green sand (from island rocks). The sand is the color of the sediments that are weathered and deposited on the coastline. In the national park most of the beaches are made up of black sand.

Akaka Falls – The northeastern part of the island is made up of older rock where there are more

rivers and streams. Waterfalls are dramatic examples of how flowing

water is eroding the landscape differently in different places.

Black Sand – This is a magnified view of sand found on a beach near

Hilo. It gets its black color from igneous rock that has eroded by the

Wailuku River.

Water in Hawaii Volcanoes National Park

While there are many streams on the island, very few actually flowthrough the national park. This is because the rock in the park is young. Rainfall infiltrates young rock (e.g. the peaks inside the park) too quickly for it to “pool up” at the surface. Rainfall infiltrates the older rock (e.g. the peaks outside the park) more slowly. Thus more water stays at thesurface and can carve out impressive landforms like waterfalls. The water that flows over the falls bring sediment and deposit it along the river-banks. The falls are also places where the water is dramatically eroding the land. You would find the rocks of the falls very smooth if you were to touch them.

Akaka Falls: The northeastern part ofthe island is made up of older rock wherethere are more rivers and streams.Waterfalls are dramatic examples of howflowing water is eroding the landscapedifferently in different places.

The water in the streams, rivers, and groundwater that doesn’t evaporateor get consumed by plants and animals flows directly into the ocean. Even the ocean dramatically shapes the land. The constant waves break apart and smooth recently formed igneous rock. This is why the sandy beaches take on such different colors. Beaches on Big Island are madeup of white (from ocean coral), black (from island rocks), or even green sand (from island rocks). The sand is the color of the sediments that areweathered and deposited on the coastline. In the national park most ofthe beaches are made up of black sand.

Black sand: This is a zoomed in view ofsand found on a beach near Hilo. It gets its black color from igneous rock that hasbeen eroded by the Wailuku River.

Green sand beach: This is a rare green sand beach located on the southern end of Big Island. It gets its color from the nearby igneous rocks.

Green Sand Beach – This is a rare green sand beach located on the southern end of Big Island. It gets its color from the nearby igneous rocks.

Water in Hawaii Volcanoes National Park

While there are many streams on the island, very few actually flowthrough the national park. This is because the rock in the park is young. Rainfall infiltrates young rock (e.g. the peaks inside the park) too quickly for it to “pool up” at the surface. Rainfall infiltrates the older rock (e.g. the peaks outside the park) more slowly. Thus more water stays at thesurface and can carve out impressive landforms like waterfalls. The water that flows over the falls bring sediment and deposit it along the river-banks. The falls are also places where the water is dramatically eroding the land. You would find the rocks of the falls very smooth if you were to touch them.

Akaka Falls: The northeastern part ofthe island is made up of older rock wherethere are more rivers and streams.Waterfalls are dramatic examples of howflowing water is eroding the landscapedifferently in different places.

The water in the streams, rivers, and groundwater that doesn’t evaporateor get consumed by plants and animals flows directly into the ocean. Even the ocean dramatically shapes the land. The constant waves break apart and smooth recently formed igneous rock. This is why the sandy beaches take on such different colors. Beaches on Big Island are madeup of white (from ocean coral), black (from island rocks), or even green sand (from island rocks). The sand is the color of the sediments that areweathered and deposited on the coastline. In the national park most ofthe beaches are made up of black sand.

Black sand: This is a zoomed in view ofsand found on a beach near Hilo. It gets its black color from igneous rock that hasbeen eroded by the Wailuku River.

Green sand beach: This is a rare green sand beach located on the southern end of Big Island. It gets its color from the nearby igneous rocks.