35(2), 107 119 Tjp ehl CAC KHOA HOC V£ TRAI BAT C A N H B A O N G U Y CO TRLTOT LC5 DAT CTCAC HUYEN MIEN NUI TINH QUANG NGAI PHAM VAN HUNG'''', NGUY£N VAN DUNG^ E mail phamvanhungvdc@gmail com ''''Vi^n Bia[.]
35(2), 107-119 Tjp ehl CAC KHOA HOC V£ TRAI BAT C A N H B A O N G U Y CO TRLTOT LC5 DAT CTCAC HUYEN MIEN NUI TINH QUANG NGAI PHAM VAN HUNG', NGUY£N VAN DUNG^ E - mail: phamvanhungvdc@gmail.com 'Vi^n Bia chat Vien Hdn Idm Khoa hoc vd CSng ngh^ Viet Nam ^Vi4n Dia ly, Vien Hdn ldm Khoa hgc vd Cong nghi Viet Nam Ngay nh|n bai: 14 - I - 2013 M d dau Tinh Chuang Ngai nam d vimg Duyen hai mien Trung, cd vi the vua tua vdo dai Trudng San hiing vT, viia hudng Biln Ddng {hinh l); phia bdc gidp Qudng Nam, phia nam giap Binh Djnh, phia tdy giap Kon Tum va Gia Lai vd phfa ddng la Bien Ddng Tinh Quang Ngai nam trdi dai tii 14°32' den 15°25' vy dp Bdc, tir 108°06' din 109''04' kinh dp Ddng, gdm cd phd Quang Ngai va 13 huyen, dd cd mdt huyen dao la Ly Son, huyen ddng bang va huyen mien mii (gom Ba Ta, Tra Bdng, Tdy Trd, San Tay, Son Ha va Minh Long), HInh Bdn di phdn bd TLD cdc huy$n ml^n niii tinh Qudng NgSi Dia ban cdc huyen mien mii tinh Qudng Ngdi ndm viing cd dilu kien ty nhifin rat phuc tap, hdng ndm phdi chju nhitng tSn that khdng nhd tai bi6n dia chdt gay ra; ddc biet la trupt Id dit (TLD) dang cd xu hudng ngdy mot gia tdng ca vl quy md vd tin suit xuit hi6n, de I^i nhiing hdu qua n§ng ne cho cupc sdng cua ngudi dan Nhieu doan dudng bj viii lip, thdm chi bj pha buy, Idm tS lipt giao thdng nhieu ngdy (dudng Bdng Trudng Son, quoc Id 24, tinh Id 622, 623, 626); ddi, niii, rupng vudn (Lang Mam, Gd Riia, ), nha ciia cua cu ddn bi phd huy, dd sap (thon Ddng, thdn Tdy, xd Trd San; Trd L?c, Trd Xanh, xa Trd Lam; Td BI, xd Scm Bua; Trd Ong, Trd Xudng, xa Trd Qudn; Bdc Duong, xa Trd Thp; Tra Cdt, xa Tra Thanh; Tra Linh, xd Trd Lanh; Td Dieu, Td Bau, xd San Thuy, Rudng Gd, Diep Thuang, xd Thanh An; Ddng Chiia, xa Ba Chua; Sudi Loa, xd Ba Dpng; Ldng Mam, Ldng Dieu, xa Ba Bich; Va Chdy, Ddng Ldu, xd Ba Le, ); su an toan ciia cac hd dap thiiy dien (ho Nudc Trong, Ddc Pring, Trd Bdng,.,.) cd nguy co bi de dpa, dnh hudng din ddi sdng ciia cu ddn sdng d viing dudi ddp Viec nghien ciru phdng trdnh gidm nhe thilt hai tai biln dja chdt ndi chung, TLD ndi riing gdy nen dd dupc chii trpng nhiing ndm gin day [1-4], Tai biln TLD d mdt sd dia phuang tinh dd dupc nghien cuu d miic dp khde nhau, d^t dupc nhiing kit qud nhdt djnh phuc vu cho cdng cudc phdng trdnh giam nhe thiet hai va bdo ve mdi trudng d dja phuang Tuy nhien, cho den tren dja bdn cdc huyen mien mii tinh Quang Ngai, cdn chua cd cdng trinh ndo nghiin ciiu danh gid chi tilt hipn trang vd khoanh viing canh bdo nguy ca tai bien TLD, ldm co sd cho quy hoach phdt trien bin viing KT-XH vd bdo ve mdi tnrdng Do dd, hang ndm, TLD d viing nui cdn diln bien phiic tap, khd kilm sodt va nhiing tdn that vl KT-XH d noi day cdn kha Idn Trudc ylu ciu bite xiic cua thuc tiln ddi hdi, De tai "Ddnh gid hien trang, khoanh viing canh bdo chi till nguy ca trupt Id ddt d cac huyen mien nui tinh Quang Ngai phuc vy quy hoach phdt trien ben vung" da dupc trien khai va nhiing kit qua budc ddu ddp ung ylu ciu cua thuc tien ddt hipn Cdng trinh ndy trinh bay mot phin kit qud thyc hipn de tdi nlu tren, dd thi hien chinh nhiing ket qua vl hipn trang va phan viing cdnh bao nguy CO TLD d cdc huypn mien mii tinh Qudng Ngai 108 TJii li^u vi phirong ph&p nghiSn cuu Cdc tdi li^u nghign c ^ cdng trinh ndy Id tdng hpp cdc tdi lieu phdn tfch gidi dodn anh viln tham, khdo sdt chi tilt ngodi thuc dia ndm 20112012 vd kl thiia tdi lilu nhOng ndm qua Kit qua nghien cuu dupc hinh thdnh trin ca sd tich hpp til nhilu kit qua: nghiin cuu ngodi thyc dja, phdn tich - nghien ciiu phdng vd ke thiia cdc kit qua trudc ddy Dl ddnh gid hipn trang vd phdn viing canh bdo nguy ca TLD, cdc phuong phdp dp dung bao gdm: phan tich dnh vien thdm, khdo sdt thuc dja, phan tich t6ng hpp, phan tfch so sdnh c$p (AHP ciia Saaty) vd phdn tfch khdng gian mdi trudng GIS Phdn tich anh vien thdm dupc iing dyng dl giai dodn vj trf cdc khdi trupt trin dja bdn nghien cuu Phuang phdp khao sdt thuc dja Id chu d^o dupc ling dung dl nghiin cihi ddnh gid hipn trang vd cdc ylu td tdc dpng phdt sinh TLD Q ngodi thyc dja, tiln hdnh ve chi tilt, xdc dinh quy md, cdc d$c tnmg ciia khdi truot vd nhitng yeu td tdc dpng phdt sinh TLD Tir dd, cho ph6p ddnh gid hi^n tr^ng vd diln bien ciia qud trinh trupt Id khu vyc nghien ciru, Phucmg phdp phan tich so sdnh cdp [5, 6] dupc ling dyng nhdm xdc djnh vai trd cOa timg yeu td tdng hpp cdc yeu td tdc dpng phdt sinh TLD tren ca sd cho diem vd tinh trpng sd Phuang phdp phdn tich khdng gian mdi trudng GIS dupc dp dung de xay dung bdn dd phan viing cdnh bdo nguy ca TLD Bdn dd nguy ca TLD dupc xay dyng dya trin sy hilu bilt ve cdc chuyin ddng phuc t^p tren sudn vd vl cdc yeu td gay trupt Id [5, 6] Vifc khoanh vg cdc khu vyc hiln thdi chua bj tdc ddng cua TLD dupc dya tren gid djnh rdng, qud trinh trupt Id tuang lai se dien ciing mpt dilu kien vdi cdc vu TLD quan sdt dupc dd xdy trudc Vi^c vgch ranh gidi cua cdc vung nguy co trupt id xuit phdt tir xac suat xay hien tupng, tir sy tuong ddng ciia cdc ylu td tdc ddng phdt sinh TLD nhu: dp ddc, mat dp chia cdt sau, mdt dd chia cdt ngang, ddc dilm vd phong hod, ddc tinh dja chit cdng trlnh cua dit dd, ddc dilm dia chat thiiy vdn, lupng mira trung binh ndm, boat ddng phd huy ciia diit gdy hoat dpng (mdt dp dlit giy vd ddi dnh hudng dpng lyc dirt gdy), dp che phii thyc vdt vd cdc hoat dptig kinh tl - xd hdi cua ngudi (mdt dd giao thdng) M$t khde, vi^ djnh lupng cip dd nguy ca TLD Id kit qud cua sy tich luy cdc ylu td tdc ddng phdt sinh trupt Id dupc tinh theo cdng thutc sau [5,6]: H(LSI) Trong dd: H (LSI) - Id chi s6 nhay cdm vdi tnrpt Id, Wj - Id trpng s6 cia ylu t6tiiiij , Xij - id gid trj ciia ldp thti i ylu td gdy tnrpt j xdc cao vd cd y nghia thuc tiln ung dung phuong phdp phan tfch so sdnh cdp vd phdn tich khdng gian mdi trudng GIS dl phdn vimg canh bdo nguy CO TLD se ddp ung dupc nhu cau thuc tien ddt ra, ldm CO sd khoa hpc cho phdn vimg quy hoach phdt triln ben vung kinh te - xd hpi cdc huyen mien nui ndi riing, tinh Qudng Ngdi ndi chimg Vi|c tfch hpp thdng tin mdi trudng GIS vdi phuong phdp phdn tfch da biln dd cho ph6p Ket qud nghiin ciru xdy dyng bdn di cdnh bdo nguy co TLD tr€n dja 3.1 Hi4n trgng trugV I& dat & cdc huy^n miin nUi bdn vimg niii tinh Qudng Ngdi tinh Qudng Ngai Nhu v|iy, phucmg phdp khdo sdt thyc dia kit hpp vdi phdn tfch cdc dit lifu viln thdm Id quan trpng, bdi IS cd xdc ldp chi tilt hiln trang tai biln TLD mdt cdeh day du, chfnh xdc thi mdi cho kit qud phdn vimg cdnh bdo nguy co TLD dat dp chinh Tren co sd tdng hpp cdc kit qua khdo sdt chi tilt ngodi thyc dja vd kl thira tdi lieu nhihig ndm vira qua da cho phep xac lap 809 khdi trupt Idn nhd, phdn bd tren dien tich 3245 km^ ciia huyen mien niii tinh Quang Ngai {hinh 1, 2) 14*30'45*-1608195 Hinh Bdn dd mdt dd TLD cdc huy$n mi^n nui tinh Qudng Ngdi Trd Nilu vd 06 Rd thupc xa Trd Phong, TLD Iam dnh hudng tryc tilp din gin 70 hd ddn sdng d gin dd Tai khu vyc niii Khi, cao 1.000m d thdn Bdng va thdn Tdy, xd Trd Son, vdo ndm 1999 da xuit hiln bdn vit nut ddi 200 - 300m, hinh thdnh khdi trupt rdt Idn, de dpa tinh mang vd tdi san ciia 33 hp ddn sdng dudi chan mii va budc hp phdi di ddi O huyen Son Tay, TLD hinh thdnh ddi cd phuong a kinh tuyin Son Bua - San Miia - Son Tdn - Son Mdu Nirt dit klm theo trupt Id xdy d niii Md Rdi, xa San Tdn, d thdn Td Bl, xd San Bua dd anh hudng din 20 hd ddn sinh sdng d dudi chdn mii huyen- Son Hd, TLD tdp trung thdnh ddi klo ddi theo phuang d kinh tuyin: Son Bao - Di Ldng Son Thuy - Son Ky, Son Ha - Son Giang - Son Cao Khdi trupt d xa San Bao cd quy md Idn, chiiu rpng 70m, ddi 100m vd cao 20 m {dnh 5) Trupt Id hdn hpp ddi dap v& vd vd phong hod day tdi 25-30m Khdi trupt tai xd Son Ky dien d sudn mii cao 200-300 m, ddc 35-45° Khdi trupt cd quy md Idn, chilu rpng 300m, ddi 80m vd cao 30m {dnh (5) Trupt Id hdn hpp ddi dap vd, vd phong hod day tdi 15-20m Ngodi ra, d xdm Td Dieu, thdn Td Biu, xd Son Thiiy dd xuit hipn nhiiu vit nirt vao ndm 2004, dai hang trdm mit, klm theo - Hau het cac huyen mien niii linh Qudng Ngdi Id nui rit nguy hilm cho cu ddn sdng dudi chdn deu dien trupt Id, phd huy nhilu doan dudng niii Cdc diem xdy nirt Id mil manh nhu d thdn giao thdng, rudng nuang, hoa mdu, cdng trinh kinh Td Cdn, xd Son Hdi, Idng Bd Riy, x3 Son KJf, ndi le dan sinh, anh hudng tryc tilp din hdng trdm hp Md O, xa Son Ba, lang Bd, thj trdn Di Ldng d dan dja phuang Q huyen Tra Bdng, TLD tap trung huyen Minh Long, TLD tdp trung thdnh ddi d kinh ddi keo ddi theo phuang d vy tuyen: Trd tuyen Long San -Long Mai vd phuang DB-TN Hiep - Tra Thiiy - Trd Giang, Tra Lam - Tra Son - Thanh An - Long Mdn Trin dja bdn cdc x3 Long Trd Phil Tra Thiiy, trupt Id bien xay d dp Son, Long Mdn vd Thanh An, TLD diln gay cao 200 - 250m, dp ddc >35° Khdi trupt d Trd nguy hiem cho gan 200 hp dan dmh cu d chdn niii Thiiy dien tren sudn ddc >35°, cd chieu rdng liln kl Trin ddi Nudc Dep, thdn Dipp Thupng vd 40m, dai 120m, sau m vd phong hod ddy ddi Met thdn Nudc Nhieu, xd Thanh An, mit ddt I5m {dnh /) Trupt Id ddt xay d Trd Ldm, kem theo trupt Id Idn da dnh hudng tryc tiep den vd phong hda vdi chieu ddy 15-20m, khdi trupt gan 70 hd ddn Tai xd Long Son, nirt nui kfim theo rdng 50-70m, dai 80-IOOm, keo dai dpc theo sudn Id niii xay d Gd Chanh, Gd Nay, Gd Ddi, Lac niii, pha hiiy doan dudng TL622 {dnh 2) thdn Son vd Difp San dd anh hudng tryc tiep den 150 Trd Xanh, xa Tra Lam, vet nirt tren niii Xo dai hd dan sdng d dudi chan mii, bupc phai di chuyin 50m, rdng 0,8m va sau 0,3m da lam cho 21 hd ddn Nut dat k^m theo trupt Id d sdng Liln, tai cdc xdm vdi 90 nhan khau sinh sdng dudi chan niii phai di Ddng Vdn, Kala vd Gd Pdc da anh hudng tryc tilp ddi di noi d mdi Tai huyen Tay Trd, TLD phdt den 22 hp dan bupc hp phai di ddi Tren dja phdn hinh dai cd phuang d vJ tuyin Trd Khi - Trd huyen Ba To, TLD hinh thdnh ddi cd phuong d Quan, d kinh tuyen Tra Lanh - Trd Thp - Trd kinh tuyin Ba Vinh - Ba To - Ba Bich - Ba Le, Trung Tai thdn Tra Ich thupc xd Tra Lanh, TLD ddng bic - tdy nam Ba Dpng - Ba Cung - Ba VI phd hiiy TL626, anh hudng tryc tiep den 45 hp ddn Cdc dilm nirt ddt kem theo TLD gdy nguy hilm sdng d chdn niii, TLD phd huy taluy duang vd k6 cho cu ddn dja phuang tdp trung dpc theo thung chdng trupt TL626 {dnh 3) Tai thdn Bdc Duang, lung sdng Re vd sdng Trd Nd Khdi trupt d xd Ba xd Trd Thp, TLD phd hiiy doan ducmg TL626 ddi Chua cd quy md Idn, ddi 70m, rpng 100m, sau 15m khoang 1,5 km {dnh 4) Ngodi ra, tai thdn Trd Reo, - Cac khdi tnrpt phdn bd vdi mat dp trung binh Id 10-12 khdi trupt/lOkml M^t TLD Idn, dat gid tri >14 kh6i/10km^ phdn bd d cac xd Trd Son, Trd Ldm vd Tra Thiiy, huyen Trd Bdng; Trd Qudn, Trd Ldnh, Tra Thp, huyen Tay Trd; San Bao, Son Thuy, Son Ky, huyen Son Ha; San Bua, Son Miia, San Mau va San Tdn, huyen San Tay; Long Son, Thanh An va Long Mdn, huyen Minh Long; Ba Dpng, Ba Cung, Ba Chiia, huyen Ba To Mat dd TLD 7,054kni/km^ 5,075 7,054km/km^ 3,096 - 5,075knVkm^ 1,117 - 3,096 km/km^ < 1,117 km/km ^ tuong ling Id 9,7,5,3 vd Bang 11 T h i n g k e t r v g U v v a diem s l theo y l u t l mat dd giao thdng 6- cAc huyen m i l n niii tinh Q u i n g Ngai Maide S i d i i m Di^n tich tnrpi Id" Diem si tnrcfi Id (km^) (khoc/IQO') Mat dd giao thdng (km/km') 5.075-7,054 7,054 163 140 155 227 91 576,52 812,83 779,07 875,05 202,59 0,28 0,17 0,20 0,26 0,45 Nhu vdy, d vting niii tinh Qudng Ngai, TLD hinh thdnh vd phdt trien bdi tdc dpng ciia 11 yeu td phan Trin co sd dilm cQa 11 ylu td nlu tren, cho phip xdc djnh trpng sd ciia mdi yeu td bdng phuang phdp phdn tich so sdnh cdp ciia Saaty (Saaty's Analytical Hierarchy Process- AHP), Kit qua tinh todn cho thay {bdng 12), trpng sd ciia ylu td dp ddc Id 0,209; lupng mua Id 0,163; vd phong hod, dja chit cdng trinh vd mat dp dirt gdy diu Id 0,116; dja chdt thuy vdn, ddi dpng lyc dirt gay, mat dp giao thdng diu la 0,070; mat dp chia cdt ngang, mat dp chia cdt sau vd dp che phu thyc vat deu Id 0,023 Bdn dd nguy co TLD thdnh phdn duoc xay dung trin co sd phdn lich theo timg yeu td tdc ddng ndi trin Bdng 12 Trpng s l ciia yeu t l tdc d^ng phat sinh trtryt Id* 6* cic huyen miln nui tinh Qudng Ngai VlutI EM Trpng sd 0,209 0) Lm (7) 0,163 vph (5) 0,116 Mddg (5) 0,116 Occt (5) 0,116 OOv (3) 0,070 Ddi (3) 0,070 Mdcs (1) 0,023 (1) 0,023 Dcplv (1) 0,023 Mdgt (3) 0,070 Chij thich Dd- D$ d i e , Lm- Lu'png mua trung binh nam, Vph- Vd phong hoa, Ddi- Ddi dpng lyc dut gSy, Mddg- Mgt d0 d u l gdy, Occt- Dja chdt cdng trinh, Dctv- Dia chat thuy vdn, Mdcn- Mdt d$ chia c i t ngang, Mdcs- Mat dp chia cdt sau, Dcptv- D ( che phij thpc vdt Mdgt- M^t d$ giao thong 3.3 Phdn viing nguy ca trugft l& dh cdc huy$n miin nUi llnh Qudng Ngdi Bdn dd phdn vimg cdnh bdo nguy co TLD uen dja bdn cdc huyfn miln nui tinh Qudng Ngdi dupc xdy dyng bdng phuang phdp phdn tich khdng gian mdi trudng GIS Dd Id sy tich hpp 11 ban dd thdnh phin theo cdng thuc sau: LSI (H) - 0,209 Bd_Dd + 0,163 x Bd_Lm + 0,116 X Bd_Dcct + 0, H >^ Bd_Vph + 0,116 " Bd_Mddg + 0,070 " Bd_Ddl + 0,070 x Bd_Dctv + 0,023 x Bd_Mdcn + 0,023 x Bd_Mdcs -i- 0,023 Bd_Dcptv + 0,070 Bd_Mdgt Trong dd: LSI - bdn dd nguy ca trupt Id dit, Bd-Dd: ban dd dp ddc, Bd_Lm: bdn dd lupng mua trung binh ndm, Bd_Dcct: ban dd dia chit cdng trinh, Bd_Vph: bdn dd vd phong hod vd trim tfch D^ tii, Bd_ Mddg: bdn dd m$t dd diit gdy, Bd_Ddl: bdn dd ddi ddng lyc diit gdy, Bd_Dctv: bdn db dja chit thiiy vdn, BdMdcn: bdn dd m^t dd chia cdt ngang, Bd_Mdcs: bdn dd mat dp chia cdt sau, Bd_Dcptv: bdn dd dp che phii thyc v^t vd Bd_Mdgt - ban dd mdt dp giao thdng Vipc phdn chia s6 lupng cip nguy co TLD dugrc iya chpn theo cdng thiic: Ax = (X„^- X,nm>'n; ttong dd: n- s6 cip cin phdn chia Theo nguyin tdc neu trdn, d cdc huyen miln niii tinh Qudng Ngdi, cho phip lya chpn, phdn chia cip nguy co (n = 5, Ax = 1,1796): rit thip, thip, trung binh, cad vd rit cao Cdc trj sd tuong dug ciia Bdn cdnh bdo nguy ca TLD dupc tich hpp tir cdc cip nguy ca: rit thip: