I3zf and ~Oastal Plains Have Rising Sea Level Whereas Those in Uplifting Blocks Show Falling Sea Level

Journal of Coastal Research 229-241 Fort Lauderdale, Florida Winter 1993

Relative Sea-Level Changes in China Over the Last 80 Years

Ren Mei-e

Department of Geo and Ocean Sciences Nanjing University Nanjing 210008, China

ABSTRACT _ _

REN MEI-E, 1993. Relative sea-level changes in China over the last 80 years. Journal 0/Coastal Research 9(1), 229-241. Fort Lauderdale (Florida). ISSN 0749-0208. ' .ttlllll"t.e •• Study of tide-gauge records from 32 stations shows that, in the last 20--80 years, relative sea level at 20 ~ stations is rising and at 12 stations it is falling. This results not only from eustatic sea level rise but - c..-.. j'J. mainly from recent local crustal deformations or ground water withdrawal. Stations in subsiding deltas f!I3Zf and ~oastal plains have rising sea level whereas those in uplifting blocks show falling sea level. Thus, the !2 ---A relative sea level changes in China differ considerably from place to place and a mean value for the whole ... c-L> country has little significance for the assessment of future coastal hazards. Records at two key tide-gauge stations, Tanggu and Wusong, have been corrected for land subsidence and therefore do not reveal 'relative sea level changes in these localities. An unusually high fate of relative sea level rise (> 10 mm/yr at Tanggu, Wusong and Taixi) is chiefly triggered by over-pumping of ground water. In order to mitigate disaster brought on by future sea level rise, strict measures should be taken to limit ground water withdrawal in coastal areas.

ADDITIONAL INDEX WORDS: Relative sea level, eustatic sea level, tide-gauge record, land subsi dence.

INTRODUCTION 1988, 1989; SCOR WG89, 1990). This is also true There are two kinds of sea levels: eustatic sea in China, as shown in this paper. level and relative sea level. The former is global; SHORT HISTORY OF THE STUDY OF its recent rise is chiefly due to global warming and RECENT SEA-LEVEL CHANGES IN CHINA the resulting melting of glaciers. On the contrary, the relative sea-level changes at a specific site are The first systematic treatment of recent (1950 the sum of the eustatic sea-level rise plus local 1980) sea level changes in China was by EMERY land-level change. Evidently, the latter is much and You (1981). However, their study was based more important for humankind and hence has on tide-gauge records of only 8 stations (including greater socio-economic significance. Hong Kong), therefore, the result was far from It should be pointed out that: (1) in time scale, satisfactory. A later paper by EMERY and AUBREY our discussion focuses on relative sea-level changes (1986) discussed relative sea-level changes in Chi during the past 80 years and does not include na in great detail by using both simple regression Quaternary and Holocene sea-level changes. (2) analysis and eigen analysis. But insufficient tide In resolution, the magnitude of change is in em gauge records (only 13 stations, including 3 sta and the rate in mm/yr. The purpose of our re tions in Hong Kong) and incomplete knowledge search is to provide data for designing coastal of local environmental conditions (especially ver protection measures (sea walls, storm barriers, etc.) tical deformation, ground water withdrawal, etc.) against future sea-level rise. of specific stations prevented them from obtain A marked characteristic of the relative sea level ing accurate conclusions. The same holds true for changes in the world is its great difference be works of some Chinese scientists (e.g. WANG, Z.H., tween regions and between specific localities, both 1986). But detailed studies in recent years have in its nature (rise or fall) and in its magnitude improved our knowledge of sea-level changes in (rate of rise or fall). This has been demonstrated Shanghai (CHEN, X.Q., 1991; WANG, B.C. et al., by many previous publications (e.g., AUBREY and 1991). However, a comprehensive and more reli EMERY, 1986; EMERY and AUBREY, 1980, 1986, able account of relative sea-level changes for the whole of China is still lacking. It is hoped that this paper will help fill this gap. In this connection, a very peculiar condition in 91084 received 28 September 1991; accepted in revision 26 March 1992. Chinese tide-gauge records must be noted. Some 230 Ren Mei-e

accessible, only mean monthly water levels have

Z.35 been used in regression analysis, the results of which are shown in Figure 3 and Table 1. ,-_./ ~ 2.30 r-'" It may be noted that the sea-water surface near r-' r-' ~ ",__ J the coast of China is not uniform, being higher in 0 r----~ r-; ,/,.. 0) 2.25 South China than in North China. Thus, the ab ,...------0.,,-; A. r: -' HuangPu Park ~ solute elevation of Zhujiang (the Pearl River) zero 3 Wusong cv 2.20 datum, used by stations of Guangdong Province, > ~ '~=-J is 59 em higher than the Yellow Sea zero datum 2.15 (Yellow Sea mean sea-water surface). In China, different zero data are used by tide-gauge stations Z.10, """'" 1912 16 ZO 24 as ,~ 36 40 4-4 48 S:? in different parts of the country, the elevation of which differs considerably from each other. How Figure 1. Sea level curves at Wusong and Huangpu Park before ever, as this paper deals with relative sea-level and after correction for land subsidence, 1912-1952. (after ZHU, 1990). (Solid line, after correction; dashed line, before correc changes, difference in elevation of zero datum will tion.) not affect our result. All tide-gauge records have been carefully stud ied and evaluated in connection with local tec Chinese tide-gauge stations, notably two key sta tonic framework, recent vertical deformation, land tions at Tanggu and Wusong, have made land subsidence and human activities. subsidence corrections in their records, Tanggu The relative sea-level change at a specific site since 1959, Wusong since 1922. It is evident that is greatly affected by land subsidence because the the corrected tide-gauge records do not reveal the rate of land subsidence may be 10-100 times true relative sea -level changes at the specific sta greater than that of eustatic sea-level rise. The tions. This can be clearly seen by comparing sea cause of land subsidence may be natural or human level curves of Wusong before and after correction induced. The most important natural factor is (Figure 1). recent vertical crustal movement or vertical de Moreover, as zero datum at some stations had formation. Between 1951-1982, repeated precise been changed through time, utmost care must be levelling was carried out over the whole country taken when using Chinese tide-gauge records. and a map on recentvertical deformation in North Overlooking this important fact has contributed China has been published (Figure 4). The map to previous errors. shows that deltas and coastal plains are areas of subsidence whereas rocky mountainous coast is RELATIVE SEA-LEVEL CHANGES FROM often undergoing uplift. The rate of subsidence TIDE-GAUGE RECORDS OF CHINA and uplift is generally 1-4 mm/yr (SHEN, 1986; In this paper, we have collected tide-gauge rec YING, 1988). ords from 28 stations (Figure 2), among which In China, human-induced land subsidence is three stations have records of nearly 80 years mainly triggered by over-pumping of ground wa (Tanggu, Wusong, Macao), thirteen stations have ter. Tianjin (Tanggu) and Shanghai (Wusong) may records of more than 30 years, seven stations have be cited as typical examples. Both cities are lo records of 20-30 years, four stations have records cated in the great deltas, the former in the old of 15-20 years, and one station (Haikou) has a delta formed by the Yellow River in 3000 BC record of only 14 years. The available tide records 1128 AD, and the latter in Yangtze River Delta. of four stations in Taiwan have a time span of According to repeated precise levelling, the back less than 18 years, but the trends of relative sea ground value of recent crustal sinking in North level changes have been worked out (C.C. LID, China Plain is about 1.0-1.5 mm/yr. But it reached 1989). All records except the four Taiwan stations approximately 2.0 mm/yr in the Tianjin urban have been subjected to linear regression analysis. area where a benchmark subsided 38 mm between Because detailed Chinese tide-data are not easily 1931 and 1951, averaging 1.9 mm/yr. Since over-

--t Figure 2. Tide-gauge stations in China.

Journal of Coastal Research, Vol. 9, No.1, 1993 --..f " d.HU!Ud~~-----"'1'\ Y / ------' ""I ;U :" ) \ ~ 14t~ Q ~ ( I 7 L I --r inghuangdao~/D, '0\),,~ /1/! '" 'I ~ ,1, \" Bei'inrI 9 Tanggu \ c::G'Dalian ·r Korea 0 ) Ll ',,> "\ longkou ~'\" \ ; Japan~O\'!35 0" .'to "'??',ff'r.ry' .•\ C '" r: I /o(J ~ ~tal ~ i ,,~~J: .s->: 'v~ , Y_~Ir~gjiaogou ~\ 1"" / I ) ~Q <»>~o ingdao? I ---- .. ' "~\ _~~ ( 1'f~,X(/ qSh1liushuo _------~«5~2~ r ~:?'~ ~ :'Co; (~ /' I ~~_--+-+----- , "':JiJ'J:.",:~" .' v :)~r:'-""V'" / , 7 ...... ~~~')Io--Lianyungang '0 '. )~~~?)'---L,,1\ 8i!§'1i: \ C '---e-i ~ o E; ~ ~ ~ :. r> l;,' l", . ,: ;- .i->30 :::s e.- ~. 'b-lUSI .,~/. .i->: O ~ ~ *e8 .~ ,~••;Wusong,'~C J .i->: 00 o .i->:: ~ o I Sh~nghai ------~ ~ ,I . ,, t-- ~ (D e. ~4Changtu~ <: ::c ~~ ~ ~ ,J- '\ 7 ---- ("" "" Pacific o r:J'J ~~ {!' ::r ~ ;./',~: ~ E C' ~ ~ , ast h,na Sea :::s ~ (J'q ~ ?'" c:/~Kanmen r:J'J < S" ~ • i~~a~sho' Chi~a Se~ . I l/ : South fslandsj" n 50 /: ~~ ~ J:5--t----7-----1--=-t.., ::r !I+II ;' ,I"? ~ I 'at~ ~(-. S' Z ~ (;)IUI ~ _------~ >...:~ S' ~v,-- (', . IV i r- ; A,OIPmtan Keel ._/----- 1,1 fl. I /: I--' ung--. " ~ '( (I ----t---~20 to _ ,_-.""'.J---.--A to ---~----~J------' ~ ~' co "" -+-+- "" T. rod, . \ \,-J l 0 "/ 9'Xlamen Il6TaixiL,~-----T'! alw10n I. i.. .' " ": \.. I; : l .s;i"- , • -. \! ".' . uJ ; "~~:'?--~"S:'n-p~~~::~angp~h~lanJ~DOngSha,"~. 'i(", 7fUgUng \ :r-,\\ South ~i~~~~,~" . :Maeao~ "J~ .' \. '0 ' ' U t ' .v: .l., ,-,_. I ~c<:;;'" .'. Hongkong , Hengehunl "\ :)' /.'] '. I. jJt? ' "V,etnam~\lr7Zh'~I~''t Sanzao '; \.1 "" _-Dt-~----+- ~-~lO _-/-~. o I, ., a/po.. ~,---,-'·r--·--'v', .i->: , ' 1;::/ Weizhou~._--:. '-So-;;;h'C--"-;~-~-Sea: _-.-----.-.l- .. I .:j/.~./',:~-~~"· '1\ ,0: '., '--- .. I ~ T' (J, I ""i ('--."~) " ,,---rr--~ ~/ I ..P- _:_~ ..__ -~110------' I I " I'~ \ ;;- I r!J",,:~i'i if, " - - -,h-- - __LL. _ I /.;-s L~l!1ili!t&Ui:$iiWjfIHilllt:Lil;&/ilr 120 125- - ---"'lto--I '15 --- I = ~ ~ 232 Ren Mei-e

Dal ian

---..J I & I 54 58 62 66 7'0 7'4 /8 c;Z a'6 g'O yeor cml Huludao ~:::::::=-::~ A o. .. ::: I ! I ~2 ~ ::::: cmt 54 58 66 70 74 . 78 82 86 90year QingHuongidQ~=:::~:::': :: I £t 5l 58 62 66 70 74 78 82 86 90 year ~tOi ~ :·.:t4'8~}?::~,R .... 4.6 13 17 21 ~5 29 ~3 37year

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54 58 62 66 70 74 =Ol""~""78 82 86 90~

Journal of Coastal Research, Vol. 9, No.1, 1993 Sea-Level Changes in China 233

em 250

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pumping of ground water had not begun in this The situation in Tianjin coastal area is similar time, the rate of subsidence of the benchmark may to the urban center. In Tanggu, with over-pump roughly represent the background value of recent ing of ground water, the rate of land subsidence crustal sinking in the Tianjin urban area. Since was greatly increased since the mid-1970's, reach 1959, owing to over-pumping of ground water, the ing 137 mm in 1984. Since 1985, strict measures rate of land subsidence in the Tianjin urban area were taken to limit ground water pumping and rapidly increased, reaching 81.6 mm/yr between land subsidence was reduced to 28 mm in 1988. 1970 and 1984 (Figure 5). The trend of land subsidence on the coast near

Journal of Coastal Research, Vol. 9, No.1, 1993 234 Ren Mei-e

Kanmen . p ~ ~ . .'. ~c:;z::o::;:;:::ZOA

Sansha ~ ~ - ;:;~<:HJ4¥ .

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Tanggu may be seen from the land subsidence ing Beipotai station) began in 1910. Average rate curve at Haihe Lock which is only 3 km from of relative sea-level rise was 1.77 mm/yr between Tanggu tide-gauge station (Figures 6, 7). 1910-1937 when ground water had not been ex Records at Tanggu tide-gauge station (includ- ploited. This figure approximately indicates the Journal of Coastal Research, Vol. 9, No.1, 1993 I Sea-Level Changes in China 235

em 10 Huangpu

0 '\ 7~~ a.~ 10 ~. ~id'

66 70 74 78 82 86 year ern 710

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140 -----=.I::------L._~--I-~---'--~~---I-____:::_';::_--t.-~~.I , l 70 74 Figure 3. Linear regression line of tide-gauge records in 28 Chinese stations listed in Table 1.

sum of eustatic sea-level rise plus neotectonic in the fact that since 1959, correction for land sinking. But, it is utterly incomprehensible that subsidence has been made in tide-gauge records. according to the tide-gauge record, the average Between 1959-1985, the correction totals 129 em rate of relative sea-level rise was only 1.2 mm/yr or 47.8 mm/yr. Also, the zero benchmark at Tang between 1959-1985 when large quantities of gu tide-gauge station sunk 48.9 em between 1966 ground water were pumped. The explanation lies 1985, or 24.5 mm/yr. From the above, it is ap-

Journal of Coastal Research, Vol. 9, No.1, 1993 236 Ren Mei-e

Table 1. Relative sea-level changes at major tide-gauge sta- of ground water pumping had reduced subsidence tion in China during the last 20-80 years. of the zero benchmark to 4 mm between Novem ber, 1985 and October, 1986. Hence, the relative Rise (+) or Rate sea -level rise should also decrease to about 5 mm No. Station Period Fall (-) (mm/a) (the sum of land subsidence plus eustatic sea-level rise). However, the low figure (4 mm subsidence) 1 Dalian 1970-1989 + 3.07 2 Huludao 1960-1989 + 1.86 is limited to the site of the tide-gauge station. The 3 Qinghuangdao 1960-1989 1.95 land subsidence in this period was much greater 4 Tanggu (10-20 mm/yr) in the whole area of Tianjin New 4(1) Beipotai 1910--1936 + 1.77 Port where the tide-gauge station is located. Also, 1937-1953 0.43 4(2) Beipotai Hangu and Dagong, a little north and south of 4(3) 6 meter 1959-1985 + 1.20 5 Yangjiaoguo 1952-1986 1.20 Tanggu, are still subsiding at a rate of 100 mm/ 6 Longkou 1961-1989 1.31 yr. It is evident the rate of relative sea-level rise 7 Yangtai 1960--1989 3.39 at Tanggu tide-gauge station is not true for other 8 Qingdao 1952-1985 1.07 parts of the coast of 'I'ianjin, Therefore, in the 9 Shijiushao 1968--1989 0.85 10 Lianyungang 1963-1985 1.86 risk assessment on future sea-level rise, care should 11 Lusi 1969-1989 + 8.72 be taken in using the record of one key station as 12 Wusong 1912-1936 + 2.50 a basic scenario for the coast of the whole delta. 1957-1983 + 3.00 The case of Shanghai is similar. According to 1960-1989 2.42 13 Changtu + records at Wusong station, the average rate of sea 14 Kanmen 1960-1961 + 2.10 1963-1989 + 2.10 level rise is 2.79 mm/yr between 1955-1989. But 15 Sansha 1973-1989 + 1.10 tide-gauge records have been corrected for land 16 Pintan 1967-1989 + 1.77 subsidence since 1922, the total amount of cor 17 Xiamen 1958--1989 + 2.31 rection reaching 87.7 em between 1923-1963, or 18 Dongshan 1960-1989 + 0.24 19 North Point, 1962-1988 + 2.60 21.4 mm/yr. The great temporal variation of the Hongkong rate of land subsidence at Wusong is shown in 20 Taipokau, 1970--1988 5.00 Figure 8. In the Shanghai urban area, although Hongkong land subsidence has been essentially brought un 1971-1985 2.00 21 Chiwan der control since 1965 it is still considerable at 22 Sanpanzhou 1967-1984 + 0.39 23 Huangpu 1967-1985 0.69 Wusong where a benchmark sunk 6.8 mm/yr be 24 Macao 1925-1973 0.09 tween 1975-1985. Therefore, the true relative sea 25 Sanzao 1966-1985 + 3.28 level rise at Wusong in the last twenty years should 26 Zhaipo 1959-1989 + 2.60 be the sum of 2.79 mm plus land subsidence 6.8 27 Weizhou 1960-1989 + 6.09 28 Haikou 1976-1989 + 3.85 mm, i.e. 9.59 mm. Along the Huangpu River, a 29 Keelung + 6.00* little upstream from Wusong, the rate of land 30 Taixi + 27.80 subsidence in several localities is about 10 mm/ 31 Hengchun + 0.20 yr. For the Shanghai urban area, Guo documented 24.50 32 Fugung that between 1921-1987 the total amount of land * Figures of four Taiwan stations (station No. 29-32) after C. subsidence was 1.80 m, averaging 27.2 mm/yr. Ac C. LIlJ, 1989. cording to recent measurements at 265 points in 128 km2 area of Shanghai, the mean rate of sub parent that during the last 30 years, the true rate sidence between 1978-1987 was 4.68 mm/yr (13.6 of relative sea-level rise at Tanggu should be 24- mm in 1987) (Guo, 1991). 48 mm/yr. In Taiwan, Taixi on the western coast has the In areas of rapid land subsidence due to ground largest value of relative sea-level rise, 27.8 mm/ water over-pumping, great temporal and spatial yr. This is also mainly due to over-pumping of variability in the rate of relative sea-level rise ground water for aquaculture. should be noted. With increased ground water The example of Hong Kong also illustrates the pumping, subsidence of the zero benchmark at important role of humans affecting local relative Tanggu tide-gauge station increased from 3.5 mm/ sea level. North Point and Taipokou stations are yr between 1966-1970 to 44 mm/yr between 1977- only 17 km apart (Figure 9), but the former reg 1985 and the rate of relative sea-level rise must isters a rising sea level while the latter has a falling be correspondingly increased. Drastic reduction sea level. The main reason for this discrepancy is

r Journal of Coastal Research, VoL 9, No.1, 1993 j Sea-Level Changes in China 237

Yellow sea

D--__~...

...... - fault --- iso bose

100, 200 km

Figure 4. Vertical displacement (mm) in North China Plain, 1951-1982. (modified after CHEN, S.P., 1990). that the former is located on newly reclaimed land rocky hills. Therefore, in the Pearl River Delta, which is still subsiding whereas the latter lies on relative sea-level changes are essentially deter a rocky basement which is uplifting along an ac mined by vertical movements of active faults. Sta tive fault zone (YIM, 1988). tions on sedimentary layers generally have a rising The Pearl River Delta is different from both sea level but a few stations near or on rocky terrain the Yellow River Delta and Yangtze River Delta register a falling sea level (e.g. at Huangpu and in that it is criss-crossed by a complex set of active Chiwan). faults; Quaternary sediment cover is thin (gen The dominant influence of geotectonics on the erally 20-30 m); withdrawal of ground water is relative sea-level changes is vividly shown in the insignificant and the surface is dotted with many contrast between the relative sea level in Yellow

Journal of Coastal Research, Vol. 9, No.1, 1993 238 Ren Mei-e

-oE ~~150c:

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5000" ) , " /972 /975 1980 /985 /988 year

Figure 5. Relation between amount of ground water pumping and land subsidence in Tianjin urban area (400 km"),

River and Yangtze River deltas and their adjacent area and that the Keelung station is located on a rocky terrain. The former are located in subsiding pier which has recently been tilted, whereas the basins; hence Tanggu and Wusong record rising coast near Hengchun is slowly uplifting (C.C. LIV, sea level. On the contrary, the latter are uplifting 1989; T.K. LIV, 1990). Two stations (Lusi and areas of the Yanshan Mountains and Shandong Weizhou) on the mainland coast also record a Massif; hence, all six stations, including the im large relative sea-level rise. Both stations have portant ports of Qinghuangdao and Qingdao have quite unique local environments. Lusi is located falling sea levels. In Taiwan, the great difference on a sandy islet off the coast of Jiangsu Province of relative sea-level changes between the east and and Weizhou is on a volcanic island near a deep west coast is striking. Influenced by the rapid up fault with strong vertical displacement. lifting of the Coastal Range of Taiwan, Fugung (north of Taitung) on the east coast records a very SUMMARY AND CONCLUSIONS large rate of falling sea level (24.5 mm/yr). By (1) Of the 32 stations listed in this paper, 20 contrast, Taixi, located on the subsiding west stations have rising relative sea level but relative coastal plain and greatly affected by over-pump sea level in 12 stations is falling (about one-third ing of ground water, has a rising sea level amount of the total number of stations). Influenced by ing to 27.8 mm/yr. Similarly, the relative sea level local environmental conditions and human activ is rising at Keelung (6 mm/yr) in the north coast ities, relative sea-level changes vary greatly from but is approximately stable at Hengchun (0.2 mm/ place to place. Therefore, an average rate of sea yr) in the south coast. The disparity may be at level rise has little significance in coastal disaster tributed to the fact that Keelung is in a subsiding prevention and risk assessment.

Journal of Coastal Research, Vol. 9, No.1, 1993 Sea-Level Changes in China 239

E ::;) 550.0 -0 -0 0

;:) m 0') c 0 f-- 500.0 Q) > 0 ...0 0 E u

c 450.0 0

0 > Q)

Figure 6. Trend of land subsidence at Haihe Lock, 1963-1985. The slight uplift in 1976-1977 is due to Tangshan earthquake, 1976.

(2) Owing to ignorance of corrections for land (e.g. REN, 1990). Although there are many uncer subsidence in tide-gauge records, many authors tainties in the prediction, it is generally agreed have published low figures for the rate of relative that eustatic sea-level rise over the next century sea-level rise at Tanggu (0.2-1.5 mm/yr) and Wu will not exceed 60-100 cm, or probably much less song (0.2-2.0 mm/yr). They departed greatly from than this amount (KENNETT, 1988, 1990; MORNER, the actual situation and minimized the risk caused 1988, 1991; PIRAZZOLI, 1990). by future sea-level rise, giving a false picture of (5) It is hard to predict future trends of relative safety which is extremely harmful for evaluating sea-level change in Yellow River and Yangtze Riv- future costal hazards and for formulating plans and measures for their prevention. (3) Relative sea-level rise in China during the last 80 years is small, generally 1-4 mm/yr. Un usually high rates of relative sea-level rise of more than 10 mm/yr is common in deltas and coastal plains and largely caused by over-pumping of ground water. This is similar to other parts of the Tian [in world, for example Bangkok in the Menam Delta New port (rate of sea-level rise 15.6 mm/yr between 1960 1982) (MILLIMAN, 1989). Therefore, to prevent fu I ture sea-level rise and the resulting disaster, a prime effort should be made to limit ground water o z 4km withdrawaL (4) The rate of eustatic sea-level rise in China over the last 80 years is small, about 1-2 mm/yr. Figure 7. Sketch map of Tanggu area. (1, tide-gauge station at New Port; 2, Beipotai; 3, Haihe Lock.) This agrees with figures given by many scientists

Journal of Coastal Research, Vol. 9, No.1, 1993 I

240 Ren Mei-e

ture, the current rate of land subsidence at Tang gu and Wusong will probably continue for some mm/c time. Therefore, the best estimate for the rate of 40 relative sea-level rise at Tanggu and Wusong over Q) the next 25-50 years is about 12-16 and 8-12 mrn/ U yr respectively, that is, a eustatic sea-level rise of C Q) 2-6 mm/yr plus land subsidence of 10 mm/yr for -0 Tanggu, 6 mm/yr for Wusong. 30 --en ACKNOWLEDGEMENTS ....0 The author is most grateful to Dr. C.L. So and :J en Wyss W.S. Yim of the University of Hong Kong, Prof. T.K. Liu of Taiwan University and Dr. C.K. -U 20 Shao of Shanghai Bureau of Water Conservancy c: and many other Chinese colleagues for help in 0 acquiring data and information for this paper. - The author wishes to express special thanks to '-I-- Prof. Charles W. Finkl of Florida Atlantic Uni 0 10 versity who carefully reviewed the manuscript and Q) improved the English text. The help of Mr. Zhang ..... 5 Ren-shun of Nanjing University for preparing sea C level curves is also gratefully acknowledged. i.... 1923 51 58 66 77 year LITERATURE CITED -51 -57 - 63 - 76 85 AUBREY, D.G. and EMERY, K.O., 1986. Relative sealevels of Japan from tide-gauge records. Geological Society Figure 8. Variation of the rate of land subsidence (mm/yr) at America Bulletin, 97, 194-205. Wusong, Shanghai, 1923-1985. CHEN SHUPENG, 1990. Some information on Quaternary environment changes from satellite image in North China Plain. Quaternary Sciences, 1990(1), 51-63. er deltas, the two most important regions on the CHEN XIQING, 1991. Sea level changes since the early 1920's from the long records of two tidal gauges in coast of China because, in addition to eustatic Shanghai, China. Journal Coastal Research, 7(3),787 changes, human activity plays a dominant role in 799. the relative sea-level changes of these regions. As EMERY, K.O. and AUBREY, D.G., 1986. Relative sealevel it is unlikely that over-pumping of ground water changes from tide-gauge records of Eastern Asia Mainland. Marine Geology, 72, 33-45. could be entirely stopped in the foreseeable fu- EMERY, K.O. and AUBREY, D.G., 1988. Coastal neo-tec tonic of the Mediterranean from tide gauge records. Marine Geology, 81, 41-52. EMERY, K.O. and You FANGHU, 1981. Sealevel changes in the Western Pacific with special emphasis on Chi na. Oceanologica et Limnologica Sinica, 12(4), 297 ._r·-·-·-·_~~ ~i 310. Guo, H.C., 1991. Causes and performance of the con ;\ struction work for flood tide prevention in Shanghai. ~TaiPOkOa~~ In: Impact of Sea Level Rise on Cities and Regions. Venice: Marsilio Editori, pp. 150-156. ~~l KENNE'IT, J.P. and BARKER, P.F., 1990. Latest Creta ceous to Cenozoic climate and oceanographic devel J 'J~~. ~~ I opments in the Waddell Sea, Antarctica: An ocean VpJU I drilling perspective. In: BARKER, P.F., KENNE'IT, J.P. I 1 c " /~ )l,'"\) (J~ et at. (eds.), Proceedings of Ocean Drilling Program, ~~~J HiI!!gkcngNor,~~_Poillt "\i I Scientific Results. Washington, DC: pp. 113,937-960. ~L~~ ~J ~;'l LIU, CHI-CHING, 1989. Impact of crustal deformation on 9. ,,, 'gII» C

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Journal of Coastal Research, Vol. 9, No.1, 1993