Biến động cửa đầm phá tam giang – cầu hai và hậu quả môi trường, sinh thái thông tin khoa học và công nghệ thừa thiên huế

~ TH6NG DCBA T I N zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDC • , • sa KHOA HQC, CONG NGHe vA M Ol TRUONG T H e r A T H IE N T ro n g s O ' n a y : • Hoa cau vuon trau • Bien dQng cua dam pha Tam Giang-Cau Hai va h~u qua moi truong, sinh thai Co che tai I~p cva H6a Duan tran 10 dau thang 11.1999 Oi san va canh quan Hue: cu li~u tai nguyen cho quy hoach phat tri~n th] Hue Cau ki~n go di tlch kien true Hue Giao due trieu Nguyen, cai gia cua Nho hoc • Ghi chu ve mai quan h~ giO'ati~u thuyet va sv thir Trung Quac NhO'ngsai lam ve danh nhan van h6a £)~ng HuyRQPONMLKJIHGFEDCBA T r v SL!phat tri~n cua Dao giao tnroc Huynh Dlnh kinh xuat hi~n • Truyen Ba tien Thien Y A Na • Va nhieu bai khao cuu khac S o ( ) 0 HUE du# S62(28) K H O A H Q C DCBA vA CONG 2000 TAP CHi THONG TIN RQPONM NGH~ T H U A T H I E N H U E M U C L U C ponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFED ,., K H O A H O C & DO l SO NG - vO QUANG YEN Hoa cau, viron trau - LE vAN MIEN Buoc dau nghien CUu cau true quan dan cac loai thuy san tir bien vao pha qua cira Thuan An - NGUYEN KHOA LAN, TR~NH DONG THU MQt so dac diern da dang sinh hoc cua cay an qua & phc Hue - Ph6ng sir anh: Chuan bi truce mua lu nam 2000 _ = 12 19 D lE N D A N K H O A H Q C - NGUYEN THANH, NGUYEN VAN SAU, TRAN HaU TUYEN Danh gia so' bo hoat dong dia dong hrc chu yeu cua bien doi voi sir an dinh bo' bien khu vue Thuan An-Tu Hien - TRAN DUC THANH, NGUY~N CHU HOI, NGUYEN HaU CU Bien dong cira dam pha Tam Giang-Cau Hai va hau qua moi truong, sinh thai - NGUYEN THANH, TRAN HaU TUYEN, NGUYEN MAl SAU Danh gia so' boZYXWVUTSRQPONMLKJIHGFEDCBA c o che tai lap cira Hoa Duan tran hi dau -, thang 11.1999-tr~n hi the ky & Thira Thien Hue -: 25 31 47 B A D T O N & P H A T T R IE N NGUYEN LUA-N Di san va canh quan Hue: Cir lieu tai nguyen cho quy hoach phat trien thi Hue - HoANG DAO KiNH Mot vai dong g6p cho viec bao ton di san van h6a vat th§ co Hue giai doan hien - DoAN CONG DIEN Vai net c o ban v§ cau kien g8 di tich kien true Hue _ 53 58 61 vA N H O A - L !C H s O ' -~ ,., , O A T N lm C -N H A N _ - LE NGUYEN LUU Giao due trieu Nguyen, cai gia cua Nho hoc - DUONG NGQC DUNG Ghi chii v§ moi quan h~ gitta ti§u thuyet va sir thu Trung Qudc - PHANVAN HoANG Buoc dau tim hidu bao "L' Ere Nouvelle" va "Nhut 'I'an bao" (1926-1929) 67 77 83 V~T - NGUYEN vAN DANG Hai van Son sir sach trieu Nguyen - TRAN DtNH SON Nhirng sai lam v§ danh nhan van h6a Dang Huy Trir (1825-1874) - THI:JtN MQC LAN N8i truan chuyen cua mot nha van: Tu BU'u Dinh den T~ Dinh 87 97 104 TlJ LI~U - ROLF HOMANN (L e A n h M in h dich) S~ ph at trien cua Dao giao108 truce "Huynh Dinh kinh" xuat hien - LYVI:JtT DUNG Truyen Ba tien Thien Y ANa 115 31 rong , RQPONMLKJIH B IE N D O N G C U A D A M P H A T A M G IA N G -C A U H A l , / " phil A 'A HaiponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA VA to u to g ? A" " A' ? " H~U Q U A M O l T R U O N G , S I N H T H A I Tr~n Due Th~nh, Nguy~n Chu H i, Nguyen H ih l C U " I M & d A u ~n tren hi to 01.1, H~ dam pha Tam Giang-Cau Hai (TG-CH) co tam quan dac biet doi voi su phat trien kinh te dan sinh khu vue 'I'hira Thien Hue nho cac gia tri tai nguyen, ma n6i bat la sinh hoc va cac chirc nang v~ sinh thai, moi trirong cua no Cac gia tri va chirc nang giin lien v6'i trang thai phat tri~n cua hai lach cira chinh Thuan An va Ttr Hien ton tai nhieu nam thong n6i dam pha voi 'bien Tuy nhien, cira lach thirong khong 6n dinh v~ Vi tri va trang thai dong mo', gay nhung hau qua tieu cue v~ sinh thai, moi trirong va kern thee nhung thiet hai IOn v~ kinh te, dan sinh Co th~ coi viec lap cira, chuyen cira dam pha la cac dang tai bien nang n~ 6'ven bo mien Trung ma khu virc Thira Thien Hue la di~n hinh Bai viet danh gia hau qua moi trirong va sinh thai cua viec lap cira, chuyen mo' cira cua he darn pha Tam Giang Tu lieu diroc sli' dung chu yeu h i· cac d~ tai cap nha mroc KT.03.11 "Nghien ciru sli' dung hop ly cac he sinh thai tieu bieu ven bien Viet Nam", KT.DL.95.09 "Nghien ciru khai thac, sli' dung hop n anZYXWVUTSRQPONMLKJIHGFEDCBA ly tiem nang pha Tam Giang" va "Danh gia tiem nang va d~ xuat hra chon khu bao ve dat ngap mroc h~ diim pha Tam Giang-Cau Hai" Phan vien Hai dtrong C U ll h9C tai Hai Phong phoi hop voi S6' Khoa h9C, Cong nghe va Moi trirong Thira Thien Hue thirc hien cac nam 1991-1999 -D!a I I Q u a tr in h h in h thanh, phat tri~n d fu n pha va s ,! r a d O i cua cac cira narndcbaZYXWVUTSRQPONMLKJIHGFEDCBA D ie u kiijn hinh th a n li 'hfnh Cac dam pha diroc hinh 6'khu bo' cat co nang hrong song manh Qua trinh hinh va phat trien cac darn pha da diroc nhieu nha khoa h9C n6i tieng the gioi nghien ciru nhir: Zenkovich (1962), Phleger (1967, 1981), Emery (1967), Nichols (1981) _ 1 V a i tr o c iia k ie n tr u e o a c h u y e n d n g k ie n ta o h ie n d a i Pha Tam Giang nam 6' ria dong bang Hue, phat trien tren nen kien tao hien dai nang yeu va chuyen tiep voi cac d6i sut tren them luc dia So voi cac khoi nang manh tay Hue va Bach Ma, no tr6' vung sut tirong doi 'I'ren nen nang yeu xuat hien cac bon trung cue bo (Cau Hai, cira song Hirong) co • Phan vien Hai dironq hoc tai Hai PhOng Sa Khoa Tap chi Thong tin Khoa hoc va Cong ngh$ hoc, Cong ngh$ va Moi trlrong Tlura Thien Hue 31 e rong' t anphu ~a Hai rti'ngtO ? ,A ~., ~ RQPONMLKJIH B IE N D O N G C U A D A M P H A T A M G IA N G -C A U 'A VA ?,,' HAl , H~U Q U A M O l T R U O N G , S I N H T H A I Tr~n D u e Th~nh, Nguyen yeu to C h u H i, Nguyen H fr u co' I M & d ftu H~ dam pha Tam Giang-Cau Hai (TG-CH) co tam quan dac biet doi c chin voi S,! phat trien kinh te dan sinh khu virc Thira Thien Hue nho cac gia tri tai a trenponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA nguyen, ma n6i bat la sinh h9C va cac chirc nang ve sinh thai, moi trirong cua no (ygu to Cac gia trt va chirc nang gAn lien voi trang thai phat trien cua hai lach cira chinh Thuan An va Tir Hien ton tai nhieu nam thong noi dam pha voibien Tuy nhien, cira lach thirong khong 6n dinh ve vi tri va trang thai dong mo, gay nhimg hau qua tieu C,!Cve sinh thai, moi trirong va kern thee nhimg thiet hai IOn 5, Vol 1, ve kinh te, dan sinh Co th~ coi viec lap cira, chuyen cira dam pha la cac dang tai bien nang ne & ven be mien Trung ma khu virc Thira Thien Hue la di~n hinh 96 Bai viet danh gia hau qua moi trirong va sinh thai cua viec lap ctra, chuyen mo' cira cua he darn pha Tam Giang Tu lieu diroc sir dung chu yeu hi cac de tai cap nha ~U6'e KT.03.11 "Nghien ciru su dung hop ly cac he sinh thai tieu bieu ven bien Viet Nam", KT.DL.95.09 "Nghien ciru khai thac, su dung hop u~n anZYXWVUTSRQPONMLKJIHGFEDCBA ly tiem nang pha Tam Giang" va "Danh gia tiem nang va de xuat lira chon khu bao v~ dat ngap mroc he dam pha Tam Giang-Cau Hai" Phan vien Hai dirong ie n C U ll h9C tai Hai Phong phoi hop voi SO'Khoa h9C, Cong nghe va Moi trirong Thira Thien Hue thirc hien cac nam 1991-1999 a Iy-D!adcbaZYXWVUTSRQPONMLKJIHGFEDCBA B7 ll Q u a tr in h h in h tic nam c chfnh 84 thanh, phat tri~n d fu n pha va s ,! r a d O i cua cac cira D ie u kifn hinh tlu in h Cac dam pha duoc hinh & khu bo cat co nang hrong song manh Qua trinh hinh va phat trien cac darn pha da diroc nhieu nha khoa h9C n6i tieng the gioi nghien ciru nhu: Zenkovich (1962), Phleger (1967, 1981), Emery (1967), Nichols (1981) 1 V a i tr o c tia k ie n tr u e u a c h u y e n d ( J n g k ie n ta o h ie n d a i Pha Tam Giang nam & ria dong bang Hue, phat trien tren nen kien tao hien dai nang yeu va chuyen tiep voi cac dOi sut tren them luc dia, So voi cac khoi nang manh tay Hue va Bach Ma, no tro' vung sut tirong doi Tren nen nang yeu xuat hien cac bon trung C1;lC b¢ (Cau Hai, cira song Huong) co • Phan vien Hai duonq hoc tai Hai PhOng T'.Ip chi Thong tin Khoa h9C va Cong ngh$ SO' Khoa h9C, Cong ngh$ va Moi trvong Thira Thien Hue 32zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA vai tro thu mroc tu cac song va cac vom nang cue b9 (Thuy Thanh, An Hoa, Phu 4.001 Vang) co kha nang lam dich chuyen suy tan cac nhanh song VaG dam pha mo r H~ dtrt gay quoc 19 phirong tay hac-dong nam coponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDC y nghra ph an dinh hirong tich chinh cua dam pha, Cac he dut gay phirong gan a vi tuyen Pho Trach, Hirong tan ( Long, Rao Trang co vai tro phan dinh va phan di dam pha theo chieu d9C Cuci ngot cung, chinh s,! nang yeu cua dong bang Hue dieu kien dang cham dan cua hinh mire mroc chan tmh VaG mra sau bien tien Flandrian da tao nen sir binh on tao J tuong doi hoac nang rat cham cua mire bien khu vue, tao tien de hinh can San] cat chan va dam pha.ZYXWVUTSRQPONMLKJIHGFEDCBA voi I cha] V a i tr o y e u to d ia h in h k e tliu a Dam pha va he can dun chan khong th~ hinh & vung bien ven be sau va doc Chinh be mat dong bang aluvi co Pleitoxen thoai va rong & ven bo Hue la tien de quan d~ hinh cac dam pha co va pha Tam Giang dang ton tai V6'i dieu kierinhu vay, hau nhir khong kha nang xuat hien dam pha moi phia ngoai dam pha hien Ngoai ra, dirong nhir la dam Thuy Tu phat trien ke thira tren nen long song co (Pleitoxen) dam Cau Hai thi phat trien tren nenmot vinh bien nho bi de cat khep kin N g u o n b i tic h c a t ta o th a n h h ~ c o n d u n c h iir i n g o tii Nguon cat khdng 10nay diroc Zenkovich (1964, 1967) giai thich la co nguon goc song Hong co bci dap nen dong bang day vinh Bac B9 VaG Pleitoxen, rmrc mroc thap hon hien tren diroi 100m Trong qua trinh bien tien, song da di chuyen ngang boi tich cat VaGven bo Binh-Tri-Thien d o i v i h in h th a n li p h ii T a m va Cong ngh$, s62(28).2000 bas Thu bAn! each dai keo ban phidc 0' gil nM do? True VinE G ia n g Phleger (1981) cho rang, hau het dam pha tren the gioi diroc hinh vong 6.000-8.000 nam qua Bidn tien Flandrian bat dau tir 17.000-18.000 nam triroc tu d9 sau 100-120m tren them luc dia Theo Shepard (1963), qua trinh bien tien, mire mroc dang cao dan den mire hien nay, den 11.000 nam truce, toe d9 dang 9mm/nam va den 6.000 nam triroc, chi 4mm/nam va sau Tap chi Thong tin Khoa hoc gi2 ngo! D~ co dam pha, phai co can dun chan ngoai tao nen tu boi tich cat Khong k~ den.cac can cat S9 phia bac cira song Lau va dong bang cat rong 16'nphia tay pha, dien tich cac can dun chan ngoai kha rong: 190km 2• Neu tinh trung binh be day cat 20m, ta co khoi hrong cat khong 10 la 3,8ty m" Trong d6, tong hru hrong cat & cac song VaGdam pha chi 120 nghin tan/nam, tirong duong 80 nghin m" C6 nghia la, neu cat trr vung nui tay Hue song mang ven bien d~ tao nen can cat thi phai can c6 47.500 nam, Trong d6, theo ket qua nghien ciru (Tran Dire Th~nh-1985, Nguyen Hiru CU-1995), tudi cac can cat nguon goc bien - gio moi chi 3.000 nam (Holoxen muon) va cac giai doan bien tien Holoxen hinh nen dong bang Hue chi 11 nghin nam V a i tr o c iia b ie n tie r i F la n d r ia n me, hon qual va b Vao ken} 33 oa, Phli 4.000 nam chi Lmm/nam Vao Holoxen gitra, khoang 6.000 nam truce, bien tien lrn pha,ponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA mo rong nhat ve phia luc dia, toc d¢ dang mire mroc cham him lai va co S\Jboi tu l htrong tich C\JCd~ tao nen dong bang Hue, co cac can cat co, dam pha co da Hl1O'Ilg tan & Quang Dien, Phu Yang, sot lai di tich va vo so cac tram, bau mroc oc, Cuoi ngot M\Jc mroc chan tlnh dang cham, lai bi triet tieu tren dOOnang yeu, dia dan cua hinh yen be co nong, thoai, lai giau nguon boi tich di chuyen ngang tir day da binh 6n tao dieu kien thuan 19'ihinh roi lap day nhanh chong cac dam pha co anh can Sang den Holoxen muon, dirong bo lui boi tu den vi trt dam pha hien va vOOcac dieu kien thuan 19'icon tri (day nong thoai, mire bien dang cham chap, giau boi tich cat) da hinh nen he can cat va pha Tam Giang Ve qui mo, pha Tam Giang 16'n hon nhieu cac dam pha co, co le cung ton tai lau dai ven bo hon khong co kha nang tao pha moo phia ngoai bien day sau, doc I ven bo Giang lat hien m Thuy Hai thi Qua [rinh p h a t tr ie n Qua trmh ph at tri~n, tien hoa cua pha Tam Giang co th~ diroc chi a giai doan: G ia i d o a r i k h & i c d u Ban dau, dam pha diroc hinh nho noi cao mot day dao cat chan ngoai vung mroc nong hep phia Qua trinh bdi tu nho dong boi tich cat doc Kh6ng bo sau da nci lien dan cac dao cat, chi d~ lai hai cira chinh & Thai DUO'Ilg lon phi a Thirong va Vinh Hai (sat phia bac ntii Vlnh Phong) S\J hinh pha bat dau ng binh bang qua trinh boi tu noi cao cua he thong can cat Linh Thai-Phu Thuan vOOtu ;6ng hru each la motdao cat chan (Sand Barrier Island) dan dan noi cao, mo' rong va keo uong 80 dai ve phia tay bac, Trong do, dong bci tich cat doc be rat manh ph at trien keo dai can dun sat bien tir cira Viet xuong Thai DUO'Ilg'I'huong NhO' do, pha bi~n d~ ban dau moi hinh rong, sau hon hien va co hai cira deu rong, mot cira ket qua can cat phia nam - co Ie & Vinh Hai sat phia bac mii Linh Thai, mot cira phia bac - co le ran bien & giap phia Thai DUO'IlgThirong va Thai DUO'IleH~ da diroc Krempt A.(1931) nhac den Cira sau bi can cat vun cao tren 20m chay dai, lap thang Giai dean khoi dau ket thuc dai cat keo dai gap hmh nen Dai :)ngudn 'I'ruong Sa chay doc ttr cira Viet xuong Linh Thai Ca hai cira Thai DUO'Ilgva en, Vinh Hai bi lap, dong thai mo cira 'I'ir Hien songdaZYXWVUTSRQPONMLKJIHGFEDCBA sa n g 1-18.000 ), 100 nam l va sau 2 G ia i d o a n tr e Pha chi co mot cira nhat & phia nam la cira Tir Hien, Vao doi Tran, quan Nguyen danh Chiem Thanh van phai qua cira nay, hai cira co Thuan An va bac Linh Thai bi lap 1: Tir Hien la cira chinh va Phu Cam la song 16'n dam Cau Hai Vao pha 1, song HUO'Ilgchi a lam hai nhanh ttr Hue, nhanh chinh theo kenh Phii Cam, Dai Giang (von la long mot pha tan) van tay bac Cau Hai - Pha Tap chi Thong tin Khoa hoc va Cong ngh~, so 2(28).2000 34 Nhanh phu, co le d6 van khu dam Sam-An Truyen V\Jc mroc dam Cau Hai co Ie Ian sau van cira Dai Giang den nga basong Nong Tir Hien la cira nhat cua pha, sau, rong.ZYXWVUTSRQPONMLKJIHGFEDCBA 2: Tu Hien la cira chinh, song Phu Cam tan, song Hirong la dong chinh d6 van dam pha Vao pha 2, qua qua trinh phat trien, cira song Hirong hie la Dai Giang bi bdi tu manh gay tiic thoat mroc Hoat dong cua vom nang hien dai Thuy Thanh lam song Huang doan Phu Cam bi tan di Song Huang tho at dong chinh bien theo huang dong-hac va co vi tri gan nhu vom nang Phu Vang dAy lech no ve phia bac va nhan hop hru song B6, d6 ve bon sut cira song Huang hien va b6i tu manh chau th6 dam pha - Pha la ell den Vin~ (can] thuo chin nlla cua' 3: S\J ach tac thoat lu phat tridn delta trieu xu6ngponmlkjihgfedcbaZYXWVUTSRQPON & phia nam dam Thuy Tu dan den mo' cira Thuan An Do khong co 16i thoat true tiep vi tri cira Thuan An bay gio, to an bo dong chay song Huang theo dam Thuy Tu co vai tro nhir kenh dan d6 mroc van dam Cau Hai Vao mila 111, dong hi song Huang tran bo Thuy Tii tao nen cac bai dao dinh huang dong chay, xam thirc li~u hai bo cat va tao nen cac bai boi ngap lu hai ben bo, lam thu hep dang k~ long to a n dan Thuy Tu Mat khac, dieu kien dac biet thuan loi, dong trieu xu6ng va cac dong hi thoat da: tao nen cac delta trieu xu6ng duoi dang ac bai chim, dao ndi (198 chan dau cira phia nam Thuy Tu Chinh cac bai dao can tro' nghiem thoat lu song Huang va dam pha, dong lu song Huang cong pha cat d6i dien d~ tao l6i thoat moo ngan nhat Vi the cira Thuan An da mo van nam 1404 cham cua dirt giai doan tre cua pha - Pha G ia i d o a r i tr u o n g th a n li Thirc day 18.giai doan suy tan cua pha, giin lien voi viec mo' cira moo Thuan An va sir phan di V\JCmroc phan: Tam Giang (tay-bac), Thuy Tu (& giira) va Cau Hai (dong-nam), khac ve hinh dang, hoan hru mroc, qua trinh tram tich va dac diem sinh thai V\JCmroc Tir dau the ky 15 den nay, cira Thuan An tro' cira chinh va l6i thoat mroc chu yeu cua song Huang; Tu Hien cira phu va bi lap, mo' vOOnhip dieu mau dan Trong giai doan co nhirng S\J kien quan nhir song Phu Cam gan nhir tan han phai khoi dao, song B6 nhap hc1nvan song Huang, song Lau u6n dong vuong goc chay thuan huang van dinh pha Tam Giang, cira Thuan An dich vi tri Ian tren cung bo dai 7km vOOchu ky 100-200 nam, vung To Da & cira Dai Giang bi boi lap tan han Pha da bi nong va hep dang k~, iroc tinh boi nong 2,4mmlnam, bei nong gan 1,5m giai doan nay, tire la d('>sau trung binh cua pha khoang gan 600 nam qua bi giam di mot mra Rieng dam Cau Hai bi b6i nong 1-1,4mmlnam, tirong img 0,6-0,8m k~ tir Tir Hien Tap chf Thong tin Khoa h9C va Cong ngh$, so 2(28).2000 Thu cua cua de c qua pha] ton don] sat dan tron chin d9n~ nhm 199 dao 35 a la cira phu.ZYXWVUTSRQPONMLKJIHGFEDCBA giai doan trirong thanh, tac dong nhan sinh da anh hirong sau sac Hai co le den tien hoa tlJ' nhien cua pha, Vi du: thi hoa ven song Hirong, dao kenh duyponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA nhat Vinh Te (doi Le) noi Lau-cira Viet, vet song Phil Cam, lap cang Thanh Ha (cang c6 gan Bao Vinh), Tan My (hien nay), diip de Q~P ngan man, ho chua ~la dong thirong ngudn, tan pha rung hrong hie cua vom t tan di gan nhir hru song h6 hia nam iep vi iy Tti co hi song am thirc r k~ long mong va dao noi lm doi dien P4 cham cua moo [huy ru l16'c, qua oi thoat oi nhip DngPhti ,song lng, cua , vung k~,u6'c a d(J sau r, Rieng ru Hien Trong qua trinh phat trien cua pha Tam Giang, nguoi luon muon chinh tri hai cira nhirng deu that bai Hai Ian dap dap lap cira Thuan An vao mra the ky 15 va mra dau the ky 20 nhung dap deu bi va Nhieu Ian khoi thong cira Tu Hien ctra hi lap deu khong congo III Bien dc?ng cua cac ctra K~ tu cira Thuan An doi, cira Tir Hien tr6' cira phu va ca hai cira deu khong 6n dinh Tinh khong 6n dinh bieu hien qua cac trang thai chuyen d6i vi tri cira, dich cira, mo' cira, lap cira, thu hep mat cat uct hoac bien dang luong cira nhieu Ian Itch su.· Dien bien cua qua trinh chuyen lap cira dam pha duoc theo doi qua cac tir D C J.-iV i~ t szi: k j lieu c6 nhir c lu u i c a n lu c cua Duong Van An (tir the ky XVI),dcbaZYXWVUTSRQPONMLKJ to a r i th u : (tir the ky XVII), P h ii b ie n tC J.-Plu c cua Le Quy Don (ttr the ky XVIII) va cac nghien ciru cua Krempt A (1931), Son Hong Dire (1974), 'I'ran Dire Thanh (1985) va nhimg dieu tra nhan dan gan day C tia T u ttu « Nhir da trinh bay, tu nhieu the ky triroc, he dam pha TG-CH chi co mot cira nhat goi la cira Tir Dung (nay la cira Tu Hien), Chi tir nam 1404, cira Thuan An mo, he dam pha moo co hai cira Tren thirc te, cira Tir Hien gem cira, cira chinh dong hi mo' thong true tiep bien 6' Vinh Hien (thon Phil An), va cira phu 6' Loc Thuy (sat mui Chari May Tay) Hai cira ngan each qua mot de cat dai km, cao khoang 2-2,5m chay doc bo Dong mroc tir dam pha bien qua cira phu phai chay vong theo mot lach nong nam sat sau de cat chan Theo ph an tich dien bien Itch su va dc}cdi~m hinh thai dong lire thi cira Vinh Hien ton tai truce, K~ tir cira Thuan An mo, dong hrc dong qua cira yeu di va dong boi tich doc bo tao nen mot doi cat phat trien day Ian cira v~ phia nam den sat mui Chari May Tay Khi cira Loc Thuy 6' Chari May 'I'ay bi tan boi lap dan thi dong III mo' lai cira chinh Vinh Hien Trang thai cira Tir Hien luon 6''mot bon trirong hop: cira chinh mo, cira phu dong; ca hai cira d~u dong kin; cira chinh dong, cira phu mo; va ca hai cira d~u mo Truong hop va hoan toan dong lire tu nhien tao Da nhieu Ian cira chinh bi dong, nhan dan t6 chirc dao nhirng sau bi lap tro' lai Lan lap cira gan day nhat vao thang 12 nam 1994 cung vay Truong hop ton tai ca hai cira d~u bi lap va phai tien hanh dao cira phu sau viec khai dao cira chinh that bai, Tren thirc te, chira Ian Tap chi Thong tin Khoa hoc va Cong ngh$, s62(28).2000 36 nao cira phu t\! mo' nhir cira chinh Truong hop it xay va ton tai thoi gian ngan vi sau dong hi mo lai cira chinh, cira phu se bi boi lap Ngay sau cira Thuan An mo, cira Tir Hien bat dau co xu the bi boi lap Vi v~y, nam Quang Thuan thir (1467), Tham nghi chau Hoa la Dang Chiem dang so xin lam viec tien loi dieu, co cac dieu lap cira Eo (Thuan An) va giu cira Ttr Dung (Tir Hien) va d~ nghi da diroc chap nhan, Dieu co nghta la sir ton tai cua cira Ttr Hien da bi de doa tir thoi va sir de doa da 0' Vinh Hien va mot 0' LQc Thuy Lich su bien dan den ton tai hai vi tri: motdcbaZYXWVUTSRQPONMLKJIHGFEDCBA dong cira Tir Hien diroc tom tiit lai nhir sau:ZYXWVUTSRQPONMLKJIHGFEDCBA B a n g 1: Bien dQng lap, m d cua Tu Hi~n ve Sl no tJ co vip Vi trf clia Thai gian Vinh Hien L9c Thuy Narn 1804 Van co Nam 1811 Ma Narn 1823 Lap danl Narn 1844 Ma nhu Narn 1953 Lap Narn 1959 Ma Nam 1979 Lap Narn 1984 Narn 1990 Ma Narn 1994 Lap Chva co Lap thu tran Ma Lap xay Ma dam rat] Moi Ian bien dong cira d~u gay kh6 khan cho doi song cong dong dan cir khu V\!C.Khi cira bi lap, ngoai viec lam ach tac giao thong va nghe khai thac bien khoi, lam thay d6i C (J cau tai nguyen va gia tri tai nguyen sinh vat dam Cau Hai bi ngot h6a Sau gan nam ke tir bi lap (12.199411.1999), mac du da diroc ke kha kien co, cira Tu Hien van bi pha mo' vao 2.11.1999 CCJnlut the ky khung khiep voi rmrc mroc dang cao 5,94m tai Hue Cling voi thoi khoang mo' nam vao 1990-1994, thoi khoang lap Ian chi nam, chtrng minh rang nhip dieu lap mo cira mau hon nhieu so voi trtroc day C tia T h u tin A n So voi cira Tir Hien, cira Thuan An co C (J che va Itch su bien dong phirc tap hon N goai che dQ dQng hrc bien san bang bo, su' bien dong cua cira lien quan too C (J che uon khuc cua doan hru song HUCJng,thay d6i tirong quan giira chu hru va chi hru c6 tac dung cua vom nang Phii Yang Do v~y, cira Thuan An da tirng ton tai nhieu vi tri cung nhir ten goi khac Itch suo b m al tiep hoan xu h cua Thuc An c den: tri tl Tinh 15m - Nam 1404, me cira Thuan An va tro cira chinh cua he dam pha c6 ten la cira Nhuyen bOi - Nam 1467, s6' dang cua Tham nghi chau Hoa la Dang Chiem diroc chap nhan, chinh quyen phong kien sai truyen dan binh lap tro' lai dam T'ilp chi Thong tin Khoa hoc /a Cong ngh$, s62(28).2000 chuy 37 ~ongthoiponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA - Cho too doi Canh Thong (1498-1504), cira mo tro' lai rp ~b6i lap Ig Chiem LU~n An) c6 nghla a del 811 bien Rat co th~ hie moo mo moo co th~ lap lai d~ han ve sau manh hon, nguoi n6 the chien hroc kinh Ian dau nam 1404 cira nho nen ngiroi thoi khau cho too doi Canh Thong Nhung Ian bien dong khong du kha nang che ngu va del tim each su dung te-quan str thoi phong kien, - Trong khoang thoi gian chimg 200 nam k~ tir nam Giap Ty (1504), cira c6 vi tri & Thai DUO'IlgH~ - Trong khoang thoi gian chimg 200 nam tiep theo cho too nam 1897, cira c6 vi tri tai lang Hoa Duan, - K~ tu nam 1897 too nay, cira c6 vi tri nhir hien - cira Thuan An (Hd Tan Phan va Ho Th~ Thu Trang, 1991) Trong thirc te Itch su, ten cira "Thuan An" chinh thirc dco xu huong nguoc vOO dong vi"mo tren toan ven be Hue Ket qua lam luong cira cang dai va va dam pha a cat cheo he cat Qua trinh khong chi xay hien ma ca vOOcac cira Ian hrot la: Thuan An cd qua khir, Nhirng pharr tich thuy thach dong' hrc va hinh thai 897, dich dan dong' hrc da neu cung phu h9'P vOOdien bien Itch su cua ciraThuan An thang 11, cira Khi cira Thuan An phat trien den thoi gian tan, tao goc cheo rat di~m cira nho vOOhe cat chan cira, toe dO dong chay se bi giam han, khong d~y diroc la mot cira tram tich cat xa stron bo ngam Ket qua la se hinh nen cac bai cat ngam lap va c a n g bi chan cira luong va cang lam giam kha nang thoat mroc cua luong lam pha triroc huan An mo' a Nhir V?y, nguyen th€! tom tat: nhan doi chuyen vi tri cira Thuan An va mo' cira khac co - Do cira suy tan, thoat mroc kern sau mot thoi gian dai dich xoay len phia bac lai la mot lach 19 CO' cira thu tich 1,5m u d6 vao nam Day la vi tri r lai tir nh ling - Do co mira cue Ion keo dai gay hi trung vOOthoi gian lap cira Ttr Hien P lu in tich sub(J I'm chieu rong han May Tay h ke cirng cira ma han chong L(>c Thuy rat ep dang k€! ve rat kern l hu6ng m o c te a tr tin la Itch su 1-6.11.1999 Chira co tnrong h9'P nao cac van lieu c6 gill nhan dam pha TG-CH co den cira nhir hien Do la ket qua pha mo' cira manh liet cua tran hi lich SU dau thang 11 vira qua Pharr tich thay rang, la mot hien tirong phat trien tv nhien co chiu anh bat thirong, hiem g?P va tac dong cua cac hoat dong' nhan sinh hirong cua cac yeu to * Nhir OOm,sau 3m chi rong tin h da biet, cira Thuan An dich chuyen vi tri va mo cira moi theo chu ky 1-2 the ky, cira Tir Hien mo' dong theo chu ky 12-20 nam truce va 4-11 nam gan day Lan chuyen cira cuoi cung cua cira 'I'huan An each day 102 nam va Ian lap cira Tu Hien cuoi cung each day nam Hien tirong xay vao dau thang 11.1999 vua qua khong phai gap Ian dau ma dien bien theo d?c di€!m tien hoa tv nhien dll biet cua dam pha va cira cua chung * Lan nay, dieu kien gay ngap lut va pha mo nhieu cira xay dieu kien dac biet bat thirong hiem thay, vi: - Mira Ion keo dai nhieu lien tuc Luong mira (16.11.1999) tai Hue la 2.288mm va tai A LuOOla 2.771mm Luong mira cao nhat a Hue vao 3.11.1999 la 978mm Luong-mira tinh tu 7giO' Tap chi ThOng tin Khoa h9C va Cong ngh$, s6 2(28).2000 40zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA cua 2.11 den 7gi6' 3.11.1999 la 1.384mm, chua tung gapponmlkjihgfedcbaZYXWVUTSRQPONMLKJIH & Viet Nam Tai Hue, Gan mire lu song Hirong dat ky luc 5,94m vao hie 14 gio 2.11.1999, cao hon 199C mire bao dong III la 2,94m va vuot 1,05m so voi dinh hi Itch sli 1983 (4,89m) gtan Trong 2.11.1999, tai Hue co hie cuong suat lu len toi Irn/gio (Nguyen Van Tr?I Hai, 1999, tap chiZYXWVUTSRQPONMLKJIHGFEDCBA K h i tu o n g - T h iiy v a n -s o 12.1999) mire - Mira cue 16n keo dai lai roi dung vao thai gian lap cira Tir Hien, nen kha cua' nang thoat mroc hai dau bi giam rat nhieu Trong luong cira Thuan char An da cat cheo qua dai can cat va dong chay song Huong bien phdi di theo 4,64 long dan uon qua cong len phia bac - Lu 16n lam mire mroc dang cao dQt bien dam p a, lam ngap tat ca cac vi tri cira c6 cua dam pha da c6 von thap, tao dong dan, phat tri~n dong xung pha tao mot hie nhieu cira - DQ't mira lu lon trung vao dip khong lanh anh hirong bi1t dau tit 1.11.1999, lam nhiet dQ giam nhanh 8-10°C sau 24 gio, gi6 dong-bac tren dat lien cap 3-4, van tee gi6 trung binh -7 m J s , ngoai khoi cap 6-7, van tOc gi6 manh nhat -2 m J s (cap 8-9) Hirong gi6 bac va dong-bac, huong s6ng chu yeu la dong-hac Song yen bo cao trung binh 0,50-0,75m, ngoai khoi s6ng cao nhat 3,0-3,5m (cap V-VI) Den 5.11.1999 lai xuat hien mot ap thap nhiet doi & phia bac quan dao Truong Sa va chieu toi di chuyen den sat bo Phu Yen-Ninh Thuan, gay anh hirong mira den khu virc Hue Dieu kien da tang cirong xoi 1&bo bien yen ngoai dam pha, g6p phan tao xung yeu mo pha ctra dong III tit dam pha * Khong k~ den cac tac dong lau dai cua ngiroi & hru vue thirong nguon, viec xay ke chan cira Tir Hien da g6p phan can thoat hi nghiern trong, lam dang cao rmrc mroc lu lon, gay pha mo nhieu cira dam pha mot hie, Neu cira Tir Hien mo, duong thoat hi bien rat ngan so voi cira 'I'huan An thi kha nang mo' nhieu cira nhir vira qua se giam di IV Hau qua hip cira, chuyen mo' cira dia I nga; khu ke tron tien don! d6i cua yen bien nhai m(>t than 3km boi I Mac du so lieu thong ke thieu lien tuc, nhirng trang thai mo cira chinh la khO' Thuan An va Tir Hien diroc coi la trang thai 6n dinh tarn thoi keo dai hon ca C6 voi ( th~ coi nhirng trirong hop dam pha chi co mot cira hoac qua nhieu cira nhir hien viec la cac trirong hop tai bien, d~ lai nhirng hau qua xau ve moi trirong sinh tiep thai va dan sinh-kinh te Xet theo quan he nhan qua thi: Tai bien ngap hi nang Moi ne keo theo dam pha mo qua nhieu cira tran lu lich su thang 11.1999 vira tin d qua la hau qua cua tai bien lap cira Tir Hien, lam cho dam pha chi co mot cira.dcbaZYXWVUTSRQPONM Hau qua u ie c la p c u a T u : H ie n 1 T a n g c u o n g n g a p lu t Ngap lut & he dam pha TG-CH va khu virc Hue la hien tirong phd bien & ven bo mien Trung Tuy nhien, phan tich tir lieu thay ro xu the vao nhung nam d6ng Tap chi Thong tin Khoa hoc va Cong ngh$, s6 2(28).2000 Vi$t sinh vao +1 T?i Hue, cao hon (4,89m) ly~n Van nen kha a Thuan di theo ip tat ca cira Tu Hien, S9 Ian ngap lut nhieu hon, lut thuong Ian va hau qua nang ne hon Gan mra the ky qua c6 gan tran lut Ian vao cac nam 1953, 1975, 1983, 1985, 1990, 1995 va 11.1999 Trir tran lut nam 1975, cac tran lai deu xay vao thoi gian lap cira Ttr Hien, Vao cac nam 1983, 1985, 1990 c6 den 4-5 tran lut moi nam Tran lu lich su thang 10 nam 1983 c6 mire hi circ dai 4,89m tren song Hirong (tren mire baa dong cap III la 1,89m) Trang tran lu 5-9.10.1995 (mot nam sau lap cira Tu Hien vao thang 12.1994), hrong mira khong qua Ian (325mm ngay), chan lu 0,97m vao gio 5.10, nhanh ch6ng dat dinh 111 sau 39 gio voi bien hi 4,64m, cuong suat 11,8cm/giG'va dat rmrc VU'Qt baa dong cap III Ian nhat so voi cac dia phuong c6 hi khac & mien Trung cung dot Ngay sau la tran lu thir hai vao 10-12.10.1995 c6 dinh 111 dat 4,8m, bien 111 0,44m (Pharr Viet My, 1995) ZYXWVUTSRQPO A e h tile g ia o th o n g Cira dam pha la huyet mach giao thong bien cua Thira Thien Hue, vi khu vue dam pha la hau cir cua van tai bien va khai thac ca bien So lieu thong Mtlien ke 1995 cho thay, chi rieng tau thuyen danh ca huyen yen bien la 8.994 chiec, nh nhat khai thac ca bien la 4.300 chiec.'· Rieng huyen Phu Loc co 785 phuong ong-Mc tien tau thuyen khai thac ca bien phai qua cira Ttr Hien Vi V?y, cira Ttr Hien 5m (cap dong lam anh hirong nghiem den nghe ca bien cua dia phirong D muoi giam thap cung anh huong den san hrong thuy san Tuy nhien, mot so doi tirong ua mroc ngot va 19' nhat, dac biet la loai ca day ( C y p r in u s Tap chf Thong tin Khoa hoc va Cong ngh$, so 2(28).2000 ceni d6i th tha b~t I Mt Hi~ chd h6 Tu hH S1! tin} chi] eel phd den chu Tu cao v6'i di~J 77 nll) h 43ZYXWVUTSRQPON qua Ian c e n tr a lis ) , ca d6i la ca kinh te lai phat trien manh ngot hoa dam pha Cac xay d6i tuong giap xac nhu tom su, tom rao, ghe ira man va 19'lai bi suy kiet, Nhimg cira Tu thay d6i sau sac ve phan loai xay d6i voi cac dong vat day khac Su' !t