Lake Tinaroo, also known as Tinaroo Dam, is a man-made reservoir on the Atherton Tableland in Far North Queensland, Australia. It was constructed between 1953 and 1958 on the Barron River close to Lake Barrine and Lake Eacham (Yidyam).

History[link]

In 1952, The Tinaroo Dam and Mareeba-Dimbulah Irrigation Scheme was approved by the state government. Construction on the dam was started in 1953 and completed in 1958, at a cost of $12,666,000. The dam wall is 45.1 metres high and traps enough water from the Barron River to create a lake 3/4 the size of Sydney Harbour with a capacity of 407,000 megalitres. When the dam was filled in 1959, the old township of Kulara near Yungaburra went underwater, and all of the residents relocated to Yungaburra and surrounding towns (see Unexpected flooding below).

The area around Kulara was among the last to flood when the dam filled. Earlier the area of Danbulla, located on Robson's Creek - which also feeds into the lake, went underwater. Most of these residents relocated to the tablelands area as their farms were resumed.

The name "Tinaroo"[link]

James Mulligan was the first European explorer and prospector to visit the tablelands in 1875. The area is now called "The Atherton Tableland" after John Atherton who settled at Emerald End Station, at the junction of Emerald Creek and the Barron River. It is reported through popular legend that upon discovering alluvial tin at the headwaters of the creek, Mr Atherton shouted "Tin, Harroo!!" to his prospecting mate - hence the name.

Unexpected flooding[link]

After the dam was completed in 1958, there was expected to be another few months before the annual rains to do some final earthworks at the base of the dam, and to clear out the final settlements in the area. Unfortunately the rains began earlier than expected and to this day there are still some pieces of large construction equipment under water at the base of the dam wall, because they were not able to be removed in time.

Creating a Dam[link]

The dam filled in the first instance according to a schedule. Once construction on the last monolith had raised it above the outlet pipes the dam wall was sealed off using a planned procedure where the prepared tunnel under monolith 19 was closed. This allowed the dam to start filling up to the river outlet level.The dam filled progressively over the next few years and did not actually overflow until 1963, far later than originally expected.

Water uses[link]

Irrigation[link]

Covering almost 1200 square kilometres, the Mareeba-Dimbulah Irrigation Area is spread across the valleys of the Barron, Walsh and Mitchell Rivers.

415 square kilometres of farmland are irrigated by the lake when it supplies its 205,000 megalitres of water each year. Farmers access this water from the extensive network of 176 kilometres of channels using either a gravity fed system or pumps. Areas not serviced by the channels can draw water from streams that have their water replenished by the Barron River, which, in turn, is fed by the lake.

Power generation[link]

The Tinaroo Hydro Power Station became operational in May, 2004 and generates 1.6 megawatts ^[2], thereby stopping 8450 tons of carbon dioxide from entering the atmosphere each year. The dam is used to regulate the waterflow for use at the Barron Gorge Power Station.

Urban water supply[link]

The townships of Tinaroo, Walkamin, Mareeba, Kuranda, Mutchilba, Dimbulah and Yungaburra are supplied from Tinaroo Dam through the Barron River.

Maintenance[link]

SunWater has scheduled a capacity upgrade to the dam spillway before 2010 to ensure its safety.^[3] According to the SunWater publicity material - there will be no capacity upgrade. The upgrade consists of reinforcing the dam to increase safety, in its current capacity.

Recreation[link]

Located on the picturesque Atherton Tableland, with the Tinaroo Range and the Danbulla State Forest surrounding it, Lake Tinaroo provides a popular tourist attraction and recreation facility for over 500,000 people a year.

Water sports[link]

Lake Tinaroo with the tops of the drowned trees still rising above the water (June 2008)

With over 200 kilometres of shoreline, Lake Tinaroo offers many bays with smooth water that are protected from the wind. To this end, the lake is often used for sailing, water skiing, houseboating and swimming. During the drought of the last few years, some of the trees that were flooded during the dam's creation have become a hazard to boats because of the receding waters. The park services that maintain the recreational areas of the dam have had to trim the dead trees that have appeared. Thankfully the dam's waters are now higher, so this is no longer a problem. There are still large areas of flooded vegetation, including trees and other man-made objects such as telephone poles, which stand around in the waters of the Lake. The degree of exposure varying with the water level. As far as I know the policy of the people that control the Lake is that standing timber should remain as fish habitat. There have been a few instances of unauthorised clearing of dead trees in some areas of the Lake.

Hiking[link]

The lake is surrounded by national park, rainforest, pine tree plantations and Australian "bush". Hiking paths wind in and out of the mountains surrounding the lake and range from a pleasant walk from the parking lot to the water-front, to week long treks around the lake and its mountains.

Fishing[link]

Many species of fish and other aquatic animals populate the lake. The ever popular barramundi can grow to an enormous size in the lake because they have no natural predators (except for the occasional speedboat). Each year, the lake is stocked with fresh baby "Barra" from the Walkamin Research Station because the fish are unable to breed due to the lack of access to salt water. Also on the menu at Lake Tinaroo are eel-tailed catfish, sooty grunter, sleepy cod, mouth almighty, archer fish, spangled perch, long tom and many species of crayfish, including the red-claw and yabby.
A Stocked Impoundment Permit is required to fish in the dam^[4].

Tilapia were illegally introduced into Lake Tinaroo and are now well established. They have been declared a noxious pest species and must be destroyed and buried if caught. It is illegal to possess, rear, sell or buy tilapia. It is also an offence to release tilapia into Queensland waterways or to use them as bait, live or dead. Heavy penalties apply if caught.

Statistics[link]

• Average annual rainfall: 1 300 mm
• Annual yield for irrigation: 205 000 ML
• Assured yield for power generation: 72 000 ML
• Full supply level: 670 m above sea level
• Length of storage: 15 km
• Type of structure: Mass concrete gravity dam
• Height of wall: 45.1 m
• Maximum base width: 35.4 m
• Total crest length: 533.4 m
• Quantity of concrete: 223 000 m³
• Quantity of rock removed for foundations: 153 000 m³
• Spillway type: Ungated, central ogee spillway
• Spillway dimensions: 76.2 x 3.7 m
• Flood inflow (maximum): 256 000 ML/day
• Spillway discharge (maximum): 106 000 ML/day
• Irrigation outlets: 2 x 1 500 mm radial gates
• Barron River outlet: 1 x 1 500 mm cone valve
• Period of construction: 1953 - 1958
• Cost: $12,600,000

Source

See also[link]

• Barron River
• Lake Barrine
• Lake Eacham (Yidyam)
• Mount Hypipamee Crater
• Mount Quincan
• The Seven Sisters

References[link]

1. ^ ^{a b} "Sunwater Current Water Storage Information". http://www.sunwater.com.au/water_store.htm. 
2. ^ http://www.gepower.com/about/press/en/2004_press/092904a.htm
3. ^ "Spillway Capacity Upgrade Program". http://www.sunwater.com.au/current_projects_Spillway.htm. 
4. ^ Fishing in Queensland dams? You may need a permit.

External links[link]

Wikimedia Commons has media related to: Lake Tinaroo

• Fishing information with lake map at Sweetwater Fishing Lake Tinaroo
• Tinaroo Education Centre

Crater Lake
Aerial view; note Wizard Island against the western rim
Bathymetric survey
Location	Klamath County, Oregon
Coordinates	42°56′37″N 122°06′24″W / 42.94361°N 122.10667°W / 42.94361; -122.10667Coordinates: 42°56′37″N 122°06′24″W / 42.94361°N 122.10667°W / 42.94361; -122.10667
Lake type	crater lake
Primary inflows	precipitation and snowmelt only
Primary outflows	evaporation and subsurface seepage only
Catchment area	23.3 sq mi (60 km2)
Basin countries	United States
Max. length	6 mi (9.7 km)
Max. width	5 mi (8.0 km)
Surface area	20.6 sq mi (53 km2)
Average depth	1,148 ft (350 m)
Max. depth	1,949 ft (594 m)
Water volume	4.49 cu mi (18.7 km3)
Residence time	157 years
Shore length1	21.8 mi (35.1 km)
Surface elevation	6,178 ft (1,883 m)
Islands	Wizard Island Phantom Ship
1 Shore length is not a well-defined measure.

Crater Lake is a caldera lake located in the south-central region of the U.S. state of Oregon. It is the main feature of Crater Lake National Park and famous for its deep blue color and water clarity. The lake partly fills a nearly 2,148-foot (655 m) deep caldera^[1] that was formed around 7,700 (± 150) years ago^[2] by the collapse of the volcano Mount Mazama. There are no rivers flowing into or out of the lake; the evaporation is compensated for by rain and snowfall at a rate such that the total amount of water is replaced every 250 years.

On June 12, 1853, John Wesley Hillman was reportedly the first person of European descent to see what he named "Deep Blue Lake" in Oregon. The lake was renamed at least three times, as Blue Lake, Lake Majesty, and finally Crater Lake.^[3][4]

Crater Lake is known for the "Old Man of the Lake", a full-sized tree which is now a stump that has been bobbing vertically in the lake for more than a century.^[5] The low temperature of the water has slowed the decomposition of the wood, hence the longevity of the bobbing tree.

While having no indigenous fish population, the lake was stocked from 1888 to 1941 with a variety of fish. Several species have formed self sustaining populations.^[6] Since 2002, one of the state's regular-issue license plate designs has featured Crater Lake.^[7] The commemorative Oregon State Quarter, which was released by the United States Mint in 2005, features an image of Crater Lake on its reverse.^[8]

Dimensions and depth[link]

Crater Lake is located in Klamath County, approximately 60 miles (97 km) northwest of the county seat of Klamath Falls, and about 80 miles (130 km) northeast of the city of Medford.^[9]

The lake is 5 by 6 miles (8 by 10 km) across with an average depth of 1,148 feet (350 m). Its maximum depth has been measured at 1,949 feet (594 m),^[1][10] which fluctuates slightly as the weather changes.^[1] On the basis of maximum depth, Crater Lake is the deepest lake in the United States, the second deepest in North America, after Great Slave Lake in Canada, and the ninth deepest lake in the world (Lake Baikal is the deepest). Crater Lake is often cited as the seventh deepest lake in the world, but this ranking excludes Lake Vostok, which is situated under nearly 13,000 feet (4,000 m) of Antarctic ice, and the recent soundings of San Martín Lake, which is located on the border of Chile and Argentina.

However, on the basis of comparing average depths among the world's deepest lakes, Crater Lake becomes the deepest lake in the Western Hemisphere and the third deepest in the world.^[11] Comparing average depths among the world's lakes whose basins are entirely above sea level, Crater Lake is the deepest.

The caldera rim of Crater Lake ranges in elevation from 7,000 to 8,000 feet (2,100 to 2,400 m).

Geology[link]

Geologic map of the lake floor

Mount Mazama, part of the Cascade Range volcanic arc, was built up mostly of andesite, dacite, and rhyodacite over a period of at least 400,000 years. The caldera was created in a massive volcanic eruption that led to the subsidence of Mount Mazama around 5700 BC: about 50 cubic kilometers (12 cubic miles) of rhyodacite was erupted in this event. Since that time, all eruptions on Mazama have been confined to the caldera.

Lava eruptions later created a central platform, Wizard Island, Merriam Cone, and other, smaller volcanic features, including a rhyodacite dome that was eventually created atop the central platform. Sediments and landslide debris also covered the caldera floor.^[12]

Eventually, the caldera cooled, allowing rain and snow to accumulate and eventually form a lake. Landslides from the caldera rim thereafter formed debris fans and turbidite sediments on the lake bed. Fumaroles and hot springs remained common and active during this period. Also after some time, the slopes of the lake's caldera rim more or less stabilized, streams restored a radial drainage pattern on the mountain, and dense forests began to revegetate the barren landscape. It is estimated that about 720 years was required to fill the lake to its present depth of 594 m. Much of this occurred during a period when the prevailing climate was less moist than at present.^[13]

Some hydrothermal activity remains along the lake floor, suggesting that at some time in the future Mazama may erupt once again.^[14]

Climate[link]

Water quality[link]

A view of the clear blue water of Crater Lake

Due to several unique factors, most prominently that it has no inlets or tributaries, the waters of Crater Lake are some of the purest in terms of the absence of pollutants in North America.

Secchi disk clarity readings have consistently been in the high-20 meter to mid-30 meter (80–115 ft) range, which is very clear for any natural body of water. In 1997, scientists recorded a record clarity of 43.3 meters (142 ft).

The lake has relatively high levels of dissolved salts, total alkalinity, and conductivity. The average pH has generally ranged between 7 and 8.^[16]

Sacred significance[link]

The Klamath tribe of Native Americans, who may have witnessed the collapse of Mount Mazama and the formation of Crater Lake, have long regarded the lake as a sacred site. Their legends tell of a battle between the sky god Skell and Llao, the god of the underworld. Mount Mazama was destroyed in the battle, creating Crater Lake. The Klamath people used Crater Lake in vision quests, which often involved climbing the caldera walls and other dangerous tasks. Those who were successful in such quests were often regarded as having more spiritual powers. The tribe still holds Crater Lake in high regard as a spiritual site.^[17][18]

Panoramic view of Crater Lake, with a portion of the original mountain's surface profile seen at left

See also[link]

Wizard Island in the lake

• List of lakes in Oregon
• Volcanic Legacy Scenic Byway
• Old Man of the Lake

Notes[link]

References[link]

• Fire Mountains of the West: The Cascade and Mono Lake Volcanoes, Stephen L. Harris, (Mountain Press Publishing Company, Missoula; 1988) ISBN 0-87842-220-X
• Geology of National Parks: Fifth Edition, Ann G. Harris, Esther Tuttle, Sherwood D., Tuttle (Iowa, Kendall/Hunt Publishing; 1997) ISBN 0-7872-5353-7
• Eruptive history and geochronology of Mount Mazama and the Crater Lake region, Oregon, Charles R. Bacon and Marvin A. Lanphere, Geological Society of American Bulletin v. 118, p. 1331–1359 (2006) DOI: 10.1130/B25906.1

External links[link]

Wikimedia Commons has media related to: Crater Lake

• National Park Service: Crater Lake
• Crater Lake Data Clearinghouse of the United States Geological Survey
• Crater Lake Digital Research Collection. Oregon Institute of Technology. Retrieved 2009-11-12.