Outline of Pingtung Coast

Encircled by sea on three sides-- the Pacific on the east, the Bashi Channel on the south, and Taiwan Channel on the west, Pingtung, the southernmost county of Taiwan Province, located at 120 ° 37'49" east longitude, 20 ° 18'5" north latitude, has a coastal line of up to 136 kilometers. With a population of more than 800000, the total area of Pingtung County is about 2800 square kilometers, 112 kilometers in length and 47 kilometers in width at the broadest point. The flat of approximately has 1300 kilometers that accounts for 53% of the whole county. The coastal area, generally, is even and flat, except the Fang Shan Hsiang , whose exceptional landform with mountains is on one side and water on the other.

In the district of Pingtung County, three state-controlled rivers—Kao Ping River, Tung Kang River, and Szu Chung River—all run across the county and then into the sea. In terms of fishing ports, Tung Kang, Fang Liao, and Hou Pi Lake are three larger-scale ports, while others in the county take advantage of the estuaries building provisional wharves as berths. Residents in the coastal areas engage in agriculture and fishery equally. Owing to the insufficient cultivatable lands and the favorable coastal position, the mixed pisciculture has boomed and flourished since 1974, as a consequence, the breeding areas has been expanded over 2000 hectares up to now. However, the rapid over-pumping of groundwater, demanded by pisciculturists, also changed the structure of the stratum, resulting in dangerous land sinking, especially in Lin Pien, Chia Tung, and Fang Liao areas, even leading to the landwards-flowing sea as well as floods.

Property of Pingtung Coast

The coastal line around Pingtung is as long as 136 kilometers and embraces 10 coastal hsiangs and towns. The coast extending from Yen Pu Village of Hsin Yuan Hsiang to Fang Liao Fishing Port is formed with sands and gravels. Its flatter terrain plus the little-diameter sand grains weaken its defense against sharp waves and make it an eroded coast. The coast stretching from the south point of Fang Liao Fishing Port to Chia Ho, Chia Lu, Fang Shan, Tzu Tung, and Feng Kang, is formed with gravels or pebbles. Whenever a rushing tide arises, the stormy waves may straightly reach to and wash out the hinterland and villages. She Liao and Hou Wan of Che Cheng Hsiang , Kang Tzu of Man Chou Hsiang , and Hsu Hai of Mu Tan Hsiang , situated on the bed of weathered laccolith at coastal areas, are easily subject to floods.     

Meteorology of Pingtung Coast-- Oceanography

A. Meteorology

1. Temperature

The highest average temperature, reaching 28.9 degrees centigrade , takes place in July, while the lowest one, reaching 19.2 degrees centigrade, appears in January. The highest temperature is 32 degrees centigrade occurring in July.

2. Air Pressure

The high pressure frequently appears in fall and winter, while the depression occurs in summer. The lowest depression, 967.3 millibars, occurs in October.

3. Rainfall

The rainfall mostly concentrates on July, August, and September, with the maximum of 469 mm appearing in July. The maximal duration of raining days is 15 days in August, and the number of annual raining days is 81.    

4. Wind

The average velocity is between 2.6~5.6 m/s with the highest one occurring in July. The annual average velocity is 3.2 m/s, and the northeasterly wind occurs the most.

5. Typhoon

The Central Weather Bureau divides typhoons into 7 categories, according to their routes of attacking Taiwan, and among which, the route 3, 5, 6 are more menacing to the coasts of Pingtung. The highest frequency of typhoons attacking Taiwan occurs in August.    

B. Oceanography

1. Current

The principal current in Taiwan area is the Japan Current, whose main current flows from the Philippines along the east coast of Taiwan to Japan, while its minor current runs through the Taiwan Channel entering the East China Sea at Chi Lung, and finally converges with the main current at the outer sea of Yilan. Generally, the current outside Pingtung flows northwards at a velocity of about 0.4~1.0 knot (i.e. 0.2m/s~0.5m/s) .

2. Tidal Current

(1) Due to the stream of rivers, the tidal currents of both Kao Ping River and Tung Kang River flow in an outward direction from the river mouths. 

(2) Within 10-meter-deep coastal area of Ta Peng Bay, the tidal current is parallel to the coastal line. Evidently, it is greatly affected by the land border and the depth of water. 

(3) At the over-10-meter-deep area outside Ta Peng Bay, the tidal current, at the rising tide, is northwestward by north while that, at the falling tide, is northeastward by north.

3. Waves

(1) Monsoon Waves

Southwest Taiwan is the lee because of the southeastward-stretching coastal line, hence the weakened winter monsoon and its waves are no more a grave menace to Taiwan's southwest coast. When the whittled monsoon waves forming above the Taiwan Channel approach the Pingtung coast, the height has been reduced less than 1.5 meters. Aithough a tropical depression is not as fierce as a typhoon, its high frequentation and its accompaniment of the southwest ward waves, whose height may reach 2 meters, do not allow people to ignore it.

(2) Typhoon Waves (see the table attached)

-Data of Typhoon Waves outside Pingtung Coast-

Type	Direction	Height (m)	Cycle (sec)
Typhoon Waves	WSW	6.0	11.5
	WSW	6.0	11.5
	WSW	6.0	11.5
	WSW	6.5	11.8
	WSW	8.0	12.2

4. Water Level (see the table attached)

-Data of Typhoon Waves Outside Pingtung Coast-

Skyrocketed Water Level             +2.5m

Highest High-Water Level (H.H.W.L.)   +2.13m

Mean High-Water Level (M.H.W.L.)     +1.5m

Mean High Level (M.H.L.)          +1.0m

Mean Low Water Level (M.L.W.L.)     +0.5m

Lowest Low-Water Level (L.W.L.L.)     +0.04m

5.Floating sands

(1) Grain type: On the north side of Ta Peng Bay's former mouth, the south and north sides of Lin Pien River mouth, Chi Feng Village, and the north and south banks of Kao Ping River mouth, there are massive areas scattered and blanketed by coarse sands.

(2) Advantageous direction: According to the researches and judgment, the advantageous direction of floating-sands along the coast shall be from southeast to northwest.

(3) Source: The sand carrying of the waves at Pingtung coast is far beyond the sand supply from its sources, as a result, the coast gets eaten away little by little; later, the eroded sands turn into the floating-sands for other places.

Typhoon & Flood Disasters along Pingtung Coast

Pingtung coast is geographically located at the sub-tropical zone, just on the routes of typhoon movement. The coast suffers badly whenever typhoons and floods attack every year, and the stormy billows and landwards-flowing sea severely endanger the life and property of coastal residents. The regions of Tung Kang, Lin Pien, Chia Tung, and Fang Liao, whose land stratum had sunken more than 2 meters, endure the harshest ordeals and disasters of typhoons and floods. The statistic data show, from 1985 to 1992, typhoons struck Taiwan and therefore destructed the dikes owned by Pingtung County 12 times in total. Because this bureau had gradually reinforced the protection of dikes and the off-coast dikes had been constructed in succession since 1992, the destruction caused to dikes by typhoons had been significantly reduced.

-Statistical Table of Typhoons Attacking Pingtung County's Dikes- (1985~1992)

Date of Attack	Name of Typhoon	Max. Velocity	Route	Dike Damaged	Location	Destruction
June 22, 1985	Hal	Medium 48m/sec	Luzon-Bashi Chan.-South Heng Chun- Hong Kong	Wen Feng	Chia Tung Hsiang	For lands sunk, waves overflowed causing 800m damage to dikes.
June 24, 1986	Nancy	Medium 38m/sec	Luzon-Hualien-Chilung-NEN	Chia Lu Tang	Fang Shan Hsiang	40m (Damaged by floods)
				Hou Wan	Che Cheng Hsiang	359m
Oct. 24, 1987	Lynn	Intense 53m/sec	Guam-Luzon- Southwest of Heng Chun-N	Nan Ping Li	Tung Kang Town	110m
June 2, 1988	Susan	Medium 40m/sec	Luzon-Tungsha Is.-Heng Chun- Ta Wu-Ryukyu	Fan Tzu Lun	Fang Liao Hsiang	310m
July 16, 1989	Gordon	Intense 65m/sec	Sulfur Is.? –Luzon-NW	Tu Chia Tso	Lin Pien Hsiang	350m
Sept. 11, 1989	Sara	Intense 51m/sec	Sulfur Is.? –Luzon- Hualien -NE cape of Taiwan-Matsu	Hu Lu Wei	Chia Tung Hsiang	20m (Damaged by floods)
				Feng Kang	Fangshan Hsiang	30m (Damaged by floods)
June 23, 1990	Ophelia	Medium 38m/sec	Phil.-Hualien-Hsinchu-East China Sea	Ta Chuang	Fang Liao Hsiang	300m
Aug. 19, 1990	Yang Hsi	Medium 40m/sec	Sulfur Is.? North Taiwan- Matzu	Wen Feng	Chia Tung Hsiang	20m (Damaged by floods)
				Tu Chia Tso	Tung Kang Town	320m
1991	Amy	Intense 51/sec	Luzon-South Heng Chun- Shan Tou	Feng Kang	Fang Shan Hsiang	125m( Damaged by floods)
Sep. 6, 1991	Outer circum- fluence of Charl			Fan Tzu Lun	Fang Liao Hsiang	80m (Damaged by floods) 250m
				Fang Shan	Fang Shan Hsiang
				Chia Lien Li	Tung Kang Town	500m
				Chi Feng	Lin Pien Hsiang	300m
				Tu Chia Tso	Lin Pien Hsiang	700m
Sep. 23, 1991	Nite	Intense 51m/sec	SW Heng Chun -Tungsha Is.- Kungku Is.- Hengchun-SW	Hu Lu Wei	Chia TungHsiang	130m
Aug. 19, 1992	Polly			Fan Tsu Lun	Fang LiaoHsiang	800m
				Feng Kang	Fang ShanHsiang	380m

*Dike Regulation in Pingtung County

The west Pingtung is part of eroded coast, and, since 1971, the coastal erosion got acute in certain areas. Without the defense of the dikes, then a plenty of lands, houses, and lives would have been drowned in the sea. In terms of the coastal protection, though the construction of dikes may be helpful to resist against waves and tide, this often results in the disappearance of beaches, induced by the erosion in front of the dikes as a result of wave reflex. As far as the long-term coastal conservancy is concerned, restoring the natural equilibrium of the coast is the goals we should try very effort to reach in the future. After this bureau completed “Pingtung County Dikes Renovation Project?in 1973, we had accomplished, up to December 1995, many public works about dikes, jetties, water gates, back-water dikes, diversion dikes, coastal protectors, off-coast dikes in succession (refer to table attached) in order to defend the coastal 9 hsiangs /towns and 20 villages against the attacks of billows and landward-flowing sea.

-Table of Pingtung County Dike Work Accomplished-

(Up to December 1995)

Work	Length(m)	Remarks	Work	Length(m)	Remarks	Total
Tung Kang Dike	650		Fang Liao Dike	1211	Diversion dike: 2	Dike: 23456m Jetty: 150m Water Gate: 2 Back-water dike: 1250m Diversion dike: 9 Coast protector: 1514.5m Off-coast dike: 53
Chia Lien Li Dike	1273	Diversion dike: 221m	Pei Shih Liao Dike	1154
Ta Peng Bay Diversion Dike	200	Diversion dike: 1	Pao Sheng Tsun Dike	Protect-or 301.5
Nan Ping Li Dike	1626		Chia Lu Tang Dike	1174
Tu Chia Tso Dike	1786		Chia Ho Dike	544
Chi Feng Dike	1000	Off-coast dike: 12 Water gate:1	Fang Shan Dike	650
Shui Li Tsun Dike	2378	Off-coast dike: 13 Off-coast dike: 24	Tzu Tung Dike	300
Wen Feng Dike	3116	Jetty: 150m Water gate:1	Feng Kang Dike	473
Hu Lu Wei Dike	373	Diversion dike: 2 Back-water dike: 1250m	She Liao anti-tide Dike	340
Hsia Liao Dike	1176	Off-coast dike: 4	Hou Wan Dike	550
Ta Chuang Dike	1117	Diversion dike: 1 Diversion dike: 2	Kang Tzu Tsun Dike	Protector:500
Fan Tzu Lun Dike	2235	Protector: 570m	Hsu Hai Protector	Protector:143

Refer to the Article 13, Section 13, Supplementary Works Instruction.