Yilan County Government - 宜蘭縣政府全球資訊網Yilan County Government - 宜蘭縣政府全球資訊網

　　Roadways that our forefathers depended on for their livelihood, including Longling Historic Trail, Caoling Historic Trail, and Paoma Historic Trail, have now become popular hiking trails. Though these are the very same roads, the air surrounding them has changed completely. Yilan's history is full of stories of how the people overcame natural barriers to make Yilan less isolated and more accessible to the rest of Taiwan.

　　But just how isolated was Yilan?

　　About five million years ago before the dawn of history, the Philippine Sea Plate rammed northwestward into the Eurasian Plate and the place that we call Taiwan today rose from the bottom of the ocean. The initial collision took place approximately where Nan'ao is today. As a result, the region between Nan'ao and Hualien is the oldest layer of rock in Taiwan.
Lanyang Plain might have been only a steep mountain or a small depression in the mountains at the time. With the Xueshan Mountain Range to the west and the Central Mountain Range to the south, the Lanyang River flowed from between the two mountain ranges. While the Okinawa Trough opened and stretched towards the southwest, the depression continued to expand and the Lanyang River carried rock down from the mountains. Millions of years finally gave birth to Lanyang Delta Plain, which drops more than 1,000 kilometers in vertical depth and covers more than 300 square kilometers in area.

　　Yilan is situated at northeastern of Taiwan. It covers an area of 2,143 square kilometers. The longest distance in the east-west direction is 63 kilometers and 74 kilometers in the north-south direction. The region is in a rough triangular shape. It is surrounded by mountains on three sides, the Xueshan Mountain Range and the Central Mountain Range in the north, the west, and the south. Only the east side faces out to the Pacific Ocean. The Lanyang River pierces through between the two mountain ranges to create the Lanyang Plain. The land falls in altitude from west to east in stages of mountains, alleys, piedmont alluvial plains, lowlands, swamps, sand hills, and finally coastlines.

　　The combined alluvial plain created by the Lanyang River and many minor streams is roughly in the shape of an equilateral triangle. The three vertices are Toucheng, Sanxing, and Su'ao, with an equal distance of 30km on three sides. The Xueshan Mountain Range sits to the northwest of the line from Toucheng to Sanxing. Geologically it is the divide between the cliffs and the plains. The Central Mountain Range sits to the south of the line from Sanxing to Su'ao. Many small streams flowing out of the valleys make the piedmont lines uneven. The line from Toucheng to Su'ao is the coastline and curves gently inland. This is where the Lanyang River flows into the Pacific Ocean between the East Harbor at Zhuangwei Village and Qingshui of Wujie Village. With abundant water resources at their disposal, the residents of Yilan live their lives mainly on the fertile Lanyang Plain.

　　The Upper Lanyang River is steep and the rapid current is highly erosive. Large amounts of silt carried by the river have little time to settle since the land suddenly drops away as it flows out of the mountains and valleys. An alluvial fan is formed as a result of scattered sand and gravel settling down. Large amounts of gravel accumulate in the shallow river bed, creating an alluvial fan that often forms into a web-like pattern. The river tends to change courses after floods caused by heavy rainfall or river overflow. The water system is tangled beyond recognition and river capture and stream piracy remain common phenomena. All of the above are characteristic of the flood plains.

　　The Lanyang River slows down as it reaches mid- and downstream where silt begins to settle. After years of deposition, the roughly equilateral triangle shaped Lanyang Plain slowly formed. Now the land is wide and flat and cities have sprung up with people living closer together and more convenient transportation. It is the most developed area in Yilan.

　　It is said that Yilan is shaped like a turtle and a snake guarding the river mouth. The turtle refers to the Turtle Island in the Pacific Ocean to the east, while the snake refers to the 106-kilometer winding coastline that stretches from Da'ao of Shicheng Village in the north to the mouth of the Heping River at Aohua Village of Nan'ao Town in the south. This smooth and slightly bending curve is roughly divided into three sections. The area from Da'ao of Shicheng Village in Toucheng to North Harbor at Wai'ao Village is a narrow rocky coastline formed by the mountains leaning directly over the sea. The coastline is full of twists and turns with many peninsulas, capes, and bays and harbors. The coastal area is narrower along a rocky coast. The land rises and falls to a greater degree and the sea runs deeper offshore. This area is a part of the Jiaoxi Fault Coast.

　　The waves clash against the cliffs day after day. As time passes, the cliffs begin to erode and become flat rock surfaces that are almost of the same elevation as sea level. Such a geological structure is known as a wave-cut platform.

　　The wave-cut platform near Dali of Toucheng is particularly wide. It runs approximately parallel to the regional stratum, which happens to run in the same direction as the northeasterly monsoon winds. As a result, erosion caused by the waves is not as severe as it is along the coastline between Bitou Cape and San Diego Cape in Keelung. Crisscrossing patterns can often be seen on the sloping geological structures.

　　A cuesta is a ridge with steep cliff on one side and gentle slope on the other. The reason for this formation is that sedimentary rocks of interchanging layers of sandstone and shale are made to rise and bend by orogenic movements. The bent layers are eroded by the waves while the bottom layers are softer and collapse inward from erosion and the top layers are harder and less vulnerable to erosion. However, as the soft bottom rocks are completely washed away, the hollow becomes larger and the top rocks lose support and fall. The result is a cuesta with asymmetrical slopes. The rocky coasts in Beiguan feature rocky coasts with wave-cut platforms and cuesta. These areas are now designated as the Northeast Coast and Yilan National Scenic Area.

　　The region between North Harbor at Wai'ao Village of Toucheng and Beifang'ao of Su'ao is called the Lanyang Alluvial Fan Coast. The ocean scenery is rather dull here. In addition to the heavy sand sediment in the rivers, the strong northeasterly monsoon winds are a defining force on the formation of this region. For example, the sand spit at the mouth of the Lanyang River is generally known as a sandbank which is levee-shaped sand sediment accumulated offshore as a result of waves and ocean currents. Along the inside of the entire coastline and under the monsoon winds there has accumulated an approximately 15- to 20- meter-high sand ridge that is steep on the east slope and gentle on the west side. The ridge hampers drainage on the plains and causes the wetlands in places including Zhu'an, Wushierjia, and Wuwei Harbor to flood after heavy rainfall or a typhoon.

　　Beifang'ao of Su'ao stretches southward towards the mouth of the Heping River at Aohua Village of Nan'ao Township and is a part of the Su'ao-Hualien Fault Coast. The coast covers an overall distance of 44 kilometers. The effect of the Su'ao-Hualien Fault towering over the coast is dramatic falls. The fault approaches the ocean and leaves virtually no flat land in between. However, there are a few deltas where rivers reach the ocean and serve as places for village settlements such as Dong'ao, Nan'ao, and Heping.

　　Su'ao Harbor is another geological treasure. Two capes, Beifang'ao and Nanfang'ao, surround Su'ao Harbor to make a perfect natural harbor. Moreover, Doufu Cape and land-tied island at Nanfang'ao are famous spectacles in coast formation.

　　In Yilan, the cold Oyashio Current from the north and the warm Kuroshio Current from the south meet here on the migrating routes of oceanodromous fish. A high concentration of plankton attracts an abundance of fish. The waters near Turtle Island are one of the three major fishing grounds in Taiwan, whereas Nanfang'ao is one of the three major fishing ports in Taiwan.

　　Whenever one rides along the North Link Railway or drives down the North Coast Highway or the Taipei-Yilan Highway, a look out to sea always reveals Turtle Island standing proud in the big blue as if pointing the visitors to a trip into Yilan. It is also the most familiar marine landmark for the locals.

　　With a total area of 2.841 square kilometers and a coastline of 8.73 kilometers, the island can be divided into the head, the back, and the tail. The head points towards southeast while the tail to the northwest. The back rises up to an altitude of 401 meters, the highest peak on the entire island. The tail of Turtle Island appears to be wagging when the seasons turn and the winds and the tides change. It adds to an element of legend to the place.

　　No one knows when the first residents arrived on Turtle Island, but Han settlements on the island in 1820. In 1975, the entire population on the island moved and relocated in Renze New Village of Daxi. The Ministry of National Defense then took over and designated the village as a military restricted area. In 1978, the village was incorporated into Daxi.

　　Since the end of martial law, there have been many proposals to open Turtle Island to tourists. After years of dedicated efforts by the Yilan County Government, Toucheng Town Hall, and elected local representatives, the Executive Yuan officially included Turtle Island as a part of the Northeast Coast National Scenic Area in 1999 and reinstated Turtle Island Village in 2000. The future development plans of Turtle Island will focus on preserving the culture and ecological resources on the island through low-density development. The plans will also incorporate whale watching on the nearby waters to create a popular attraction on the Blue Highway in northern Taiwan.

　　Yilan slants towards the east and the Piyanan Fault cuts diagonally through from northeast to southwest. Except for where the Lanyang River originates from Siyuan Pass, runs parallel to the fault upstream, and encounters fewer bends, large falls are common elsewhere along the rivers because of the fault. Formation of alluvial fans occurs at midstream. Flat low lands downstream tend to create alluvial deposits and meanders are created as a result. The river runs underground during the dry season to become an ephemeral river and again bursting into a flood in the rain season.

　　Wufengqi Waterfalls are the most famous of all the waterfalls in Jiaoxi. The name comes from the falls being in front of five steep mountains. The Kavalan Chronicles wrote they are "…named for the shape with five mountains lining up to resemble standing flags…". Therefore, the waterfalls have become a popular tourist attraction.

　　Wufengqi Waterfalls have been developed into a scenic area. The Viewing Pavilion offers a spectacular view out onto the green mountains. The top of the falls sits inside a narrow mountain chasm and flows at great speed. The bottom of the falls ends at the entrance to the Wufengqi Scenic Area where playing areas are designed for children. The water is clear and crisp, so the tourists rush in on holidays to enjoy the water and picnics. It is a perfect place to have a family outing.

　　Regardless of the season, the temperature of Su'ao Cold Springs remains a constant 22 degrees Celsius year round meaning that the water source lies underground at a certain depth, isolated from the weather and surface water. With the exception of winter when the water temperature might be higher than air temperature, the water is always cooler hence the name "cold springs". There is abundant underground water in the downstream of Su'ao River. When carbonated water bubbles to the surface from thick layers of limestone, its temperature stays near 50 degrees Celsius. However, the water is mixed with colder underground water on the top layers during the ascension while carbon dioxide in the water also removes the heat in the water to further lower its temperature. The end temperature of the water when it reaches the surface is 22 degrees Celsius and the carbon dioxide in the water rushes out to create bubbles.

　　During the Japanese colonial era, Japanese merchants saw a business opportunity in carbonated cold springs. They consequently established the first soda factory in Taiwan at the foot of Qixingshan. The product was a cold spring soda named Namunei made by taking the carbonated cold spring water, reducing the carbonic acid gas, and adding sugar and flavors. The soda was bottled in the traditional soda bottles sealed with marbles, the first of their kind in Taiwan. To drink it, one needs to tear off the seal and push hard down on the opening to make the marble drop into the bottle with a pop sound and the soda come out. The excitement of popping the marble and the sharp taste when the soda first hits the back of the throat made the marble soda a huge hit and a favorite childhood memory for many.

　　…Hot springs at Tangwei, located 23 kilometers south of the government office. Steams can be seen in the distance. If the hot springs begin to boil, many crops would be destroyed. The locals pay no attention to the seasons and bath here in winters and in summers.… (The Kavalan Chronicles)

　　The forefathers and the aboriginal people had already discovered the hot springs in Jiaoxi when Wu Sha started tilling the land in Yilan. It is as a result that the old name for the location of Jiaoxi hot springs was Tangwei. Tang referred to the hot springs and Wei the trenches in which the hot spring flowed.

　　Jiaoxi is surrounded by mountains. The hot spring trenches in the field centers send up streams of steam. The sight was named one of the eight spectacles of Lanyang and subsequently featured in enduring literary works by Wu Zhufang and Ke Peiyuan, as well as Chen Shujun, a provincial graduate of the Imperial Examinations during the Qing Dynasty.

　　When the Han first arrived here, they did not consider the hot springs to be valuable natural resources. They even worried that the hot water temperature might damage the crops and hence the saying "let's not develop this place into a boiling pot".

　　After the Japanese took over Taiwan, their love for hot springs started the commercial use of the hot springs in Jiaoxi. With Jiaoxi hot springs (Tangwei) as the center, deliberate planning carefully formed the early shape of today's Jiaoxi community. In recent years, the Yilan government has been promoting tourism, culture, and environmental conservation as its visions for the county. Consequently the government has been encouraging and very supportive of the local tourism industry. Jiaoxi hot springs have undergone rapid development and the number of tourists to Yilan has shot through the roof. Hot spring hotels and restaurants sprung up overnight. Construction firms and developers have built thousands of condominiums and vacation houses near the hot springs. Even successes have been reaped from cultivating vegetables with hot spring waters and developing warm-water fisheries downstream.

　　Yilan sits in the monsoon climate zone where the northeasterly monsoon winds reign when autumn changes into winter. The temperature is higher in the summer and heavy convection rain often occurs. Combined with a land that is high in the west and low in the east, it rains year round. Typhoon season is from September to December and there is more rainfall than on average. It rains more than 200 days a year to accumulate more than 2,700 millimeters in annual rainfall.

　　Monthly rainfall is distributed evenly. There is also ample water leftover to accumulate as groundwater. Aquifers consist of coarse sand and gravel and are located in the areas between the top of the alluvial fan and its center. The range of the alluvial fan is approximately defined by the railways. The plains along the coastlines consist mainly of sand or clay. The top and center of the alluvial fan are highly permeable. 　　

　　When there is ample rainfall, the groundwater below the surface follows the slope to the top of the fan, where pressure often turns it into springs. Coastal areas consist mainly of fine sand and clay which are less permeable. When combined with the effect of the sand hills, faster flowing groundwater from upstream breaks out onto the surface. East to the spot where the Luodong River and the Lanyang River meet is where the groundwater is most abundant on the Plain. Gushers and springs can be seen everywhere, Swimming pools including Songshumen, Longmujing, Longquan, and Longtan are all supplied by underground springs.

　　Rivers run from west to east and deposit heavy sediment. The strong northeasterly monsoon winds in the winter blow against rivers on the coastline of Yilan to form a sand hill that is 23 kilometers long, 10 meters high, and 200 to 700 meters wide. When the strong northeasterly monsoon winds or typhoons attack, the sand hill is a good shield. However, at other times such height prevents the rivers from flowing directly into the ocean and creates swamp and wetlands instead. The rivers must curve and bend to find a weaker spot on the sand hill to cross over or merge with other rivers in a collaborated effort to make it out to sea. For example, the Lanyang River, Dongshan River, and Yilan River merge near the East Harbor at Zuangwei Village to force an opening out to the Pacific Ocean.

　　Yilan is endowed and never lacks water. However, the abundance of water brings with it drainage problems. Serious floods have been common place since ancient times. Between 1796 and 1850 there have been as many as 19 recorded wind or water related disasters which caused rivers to change course and crops to flood. Yilan enters the rainy season every autumn and winter. Heavy rainfall may take place suddenly and often. It is a scene that has been described as "rising river and deep mud makes carrying objects difficult; roaring thunders accompanied by racing lightening frighten even the gods".
Among the natural disasters occurring in Yilan, typhoons are the main cause of devastation. Every year between April and October, typhoons that form in the southwest Pacific Ocean tend to proceed in a westerly or northwesterly direction. The odds that a typhoon hit Yilan, which faces the Pacific Ocean to the east, are quite high. In combination with the lack of mountains blocking its way, once a typhoon enters inland it faces no obstacle in its path. The results are often severe loss of life and property damage.

　　In the early days, the Lower Dongshan River ran on lowlands which combined with sand hills by the sea that blocked flow to the extent a reservoir was formed. Heavy rainfall always caused the reservoir to overflow. In October 1974, Yilan suffered several heavy downpours which caused major floods that broke the riverbanks, destroyed houses, and disrupted traffic. Water flooded the crop fields for months which ended in serious disaster. To mitigate flooding in lower areas, the central government began the project of straightening the Dongshan River in 1975. The project was completed in stages until finished in 1989. It not only improved the flood problems but also established a water park along the Lower Dongshan River and turned it into one of the important tourist attractions in Yilan.