Tac dng t nhien va nhan sinh dn s ph

STT Ten bal TrangMUCL'UC 3 GS.ZYXWVUTSRQPONMLKJIHGFEDCBA D u a n g H ZYXWVUTSRQPONMLKJIHGFEDCBA lin g D a t : Khoa hoc cong nghe phuc Yl:1 cong 13 bien B ik bo" 6 Hien trang moitnrong mr

STT Ten bal Trang

MUCL'UC

3 GS.ZYXWVUTSRQPONMLKJIHGFEDCBA D u a n g H ZYXWVUTSRQPONMLKJIHGFEDCBA lin g D a t : Khoa hoc cong nghe phuc Yl:1 cong 13

bien B ik bo"

6 Hien trang moitnrong mroc cira song ven bien Hai phong 28

ven bien chau th6 song Hong

bang song Hong va trung du nharn cung phat trien ben viing

H6ng

da canh tren vung dat iing triing cua dong bang song Hong

dung dat vung dong bang va trung du BAc bo

thai gian toi

cua trung du va dong bang song Hong

PTS.ZYXWVUTSRQPONMLKJIHGFEDCBA T r d n ZYXWVUTSRQPONMLKJIHGFEDCBA D u e T h r ; z n h

Phan vien Hai dirong h9C tai Hai phong

TAc OONG ~ru NHIEN vA NHAN SINH~

OEN su PHAT TRIEN~

CUA DAI VEN BIEN CHAU THO SONG HONG

M o n A U

& Viet Nam, nam & bo Tay vinh Bac bo

gia Gan day, sir phat trien cua dai yen bien

theo la nhfrng tai bien yen bo nhir ngap lut,

dong bat thirong ve khi hau, thuy van va d~c

nguon va ha hru

HINH THAI CUA DAI VEN BIEN CTSH

Dong bang trong de rong 4500 krrr', cao 1

th a p n h a t (MBTN) den 1 - 1,2 m/MBTB, be

trien tua ke vao than de, dien tich chi 2 krrr'

tich 1000 krrr', rong 5 - 15 km co ria ngoai

set bot nau hong Phia ngoai chau th6 ngarn

la d6i tien chau th6 mo rong den d¢ sau 20

H 6 i v a n n k , 1 9 9 4 )

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1 B o i t u n h a n h ZYXWVUTSRQPONMLKJIHGFEDCBA n h u n g k h o n g d e 'u r a

m a n h ,

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phan nr chieu dai bolkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBAc rS H bi xoi la voi toc

tee d¢ cue dai 30 m/nam,

va can bang boi tu 169 ha m6i nam, Toe d¢

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t r ie u th ti'p k h o n g d e 'u

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- 3,5 phia Nam cira

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e u a c a c n h n n n s o n g v e 'p h ia D o n g B a e v a

T d y N a m

(hinh 3) Trong the ky qua, nhanh chinh cira

phat trien va tan lui cua cac c6n cat can cira

nhat dinh, sir phat tri~n cua c6n cat can Ian

cua cira song lai bttt dau

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tleh <;1111& dp llr d l'y ~ 12b- Tr~lI1fdl rh!ln t~lIlCa IXI 13- l>bllg bdi cfc::h Idllg ht!P dQC hI) 14· lloollg di

chuyin ln1m lrch kilt IritlJ 1:11(11I& 1ZYXWVUTSRQPONMLKJIHGFEDCBA S -Dt b ie n qu6c Jin 1 6 - o w g dAIII\:t.'\u 211I ~ !till.

sOng v~ 197J-1973; l) NMnh chCnh d.ra slIlIg lit 1973 d~n nAV_

Mac du cac nhanh song 100 luon chuyen 5.ZYXWVUTSRQPONMLKJIHGFEDCBA T r a m ZYXWVUTSRQPONMLKJIHGFEDCBA t i c h v u n g t r ie u e o x u h u a n g

( E is n z a D 1 9 8 5 T D T h c ; n h v a n n k , 1996) do

gian ( T D T h r ; n h , 1 9 9 5 ) :

1932 - 1982: 100m/nam;

1958 - 1982: 108m/nam;

B d n e 2· P h d n b o 'd o h a t c u a tr a m tic h b d i tr ie u ( M d -m n z )

DO~NBO

B1iitrieu Tren (tren MBTB) 0,009 - 0,007 0,004 - 0,009 0,0021 - 0,0034 cao

th a p

Day.v.v

4 B 6 i tu v e n b o k e o d a i v e ' p h ia T a y

N a m

phan b6 han che 0 cac con cat va bili hien

100 tram tfch cat d~ boi tu 0 day va bai boi

nay

sang vimg cira song hinh pheu trong khoang

v a n n k , 1 9 9 1 )

min dan theo cac lap tir diroi len tren mat

d6 min dan theo ca hai phia ra bien va vao

dich chuyen v~ ( T D T h a n h v a n n k , 1 9 9 5 )

1 C a c y iu t6 ' n e n

mm/nam trong thai gian ky D~ Ttr( N C a n ,

ph at trien chau th6 c6 sir den bir tram tich

thieu hut boi tich,

1I1N1l4: m~N P<JI nlNII TII.~lllO KllU Vt"C KtM SON (193~-l9g9)

500. 1/, 1000n.,

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IMp 4- f)u<)lIg nll.R:" "i~n hung hlllh "h 111:11' nh:!' v1\o n?tlll 1989.5- VuOllg lillie biCll (lung blnh ••• 11 th:!" uh~ vl\o II!I" 19~1I Co· DC hie" v~ n !ln l x~y <lVIII:.

/

Luong mira 1.500 mm/nam tren toan hru

NhietlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBAd o trung blnh nam 23,5°C thich h9P

thang 4 nam sau, gio co t6c d¢ trung blnh

deli yenZYXWVUTSRQPONMLKJIHGFEDCBA b a chiu anh huang cua 2-5 con bao

B a n g 3:S o s d n h p h d n b ( ) ' tr d m tic k 1 0 ' lu n g c u a s o n g H o n g v a s o n g C ic u L o n g

Song H6ng 114 trieu tan/nam 1 kg/rrr' 145 km 12 - 20 km

Song Ciru Long 98 trieu tan/nam 0,2 kg/rrr' 320km 20 - 30 km

Thuy trieu nhat deu, do 100 cue dai 3 5

-4 m ( N g u y ln N g r c T h lf Y , '1984) 'So ~ai ;hai

TayNam crsn. C6 nghia la, a ria Tay

trieu t6c d¢ trung blnh 20 - 30 cm/s, circ dai

rmra Do do, dong boi tfch t6ng h9P d9C bo

cue dai 2 m

Thirc vat ngap man va co bien co vai tro

Nho cluing, bai trieu boi tu nhanh hon va bo

h?p voi mroc dang tao nen sir tan pha nang

ne.

LUll vue h¢ thong song Hong co dien tfch

lanh th6 Trung Qu6c ( L B H u y n h , 1 9 9 7 )

ng(;1n ( C y p e r u s ~ p ) va 'coi iC y p e r u s

dat ( A lo id is la e v is ) , ngao ( M e r e tr ix ) , mong tay ( S o le n g o u d i) , ngo ( C y c lin a s in e n s is )

640 - 2190 ca th~ voi 90 - 220 g sinh khoi

con, bai

2 C a c y lu t f f b ie n d o 'i v a u ic d lJ n g

Gan day, c6 nhfrng bien dong bfft thirong

( L B ZYXWVUTSRQPONMLKJIHGFEDCBA H I / S I I I / i,lkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA1 9 9 7 ), n h u n g c a c tra nyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBAI~Jt co

tran IIl Iut bao dong cap III tang len tir 7,2

3 m ( P V N iu h \· u I I I / k , 1 9 9 2 ). Khi mroc

m ro c bien co the dang cao 5 - 6 m, tao d a

sau sac Su trung hop gifra mroc dang bao va

rrie u cuong co xu h u o n g tang r6 re t, tnroc

noi tren the gioi Tai tram Hon Dau, MBTB

khoang 30 nam qua ( N N T h l 'Y V U I I I / / ; ,

1 9 9 6 ) T o e dQ nay co the cao h o n a p h a n

D O N G

bien Cl'Sl-l duoc gQP thanh 3 nhom

1 D a p d e k i w i h o a n g n o n g n g h i e p v a

n u o i tr o n g tlllly s d n

dam nuoi tr6ng thLIYsan lai tang len co tinh

gian c h i 10 narn (1983 - 1993) Thong ke

x o i 1 0 b o bien B o Van Ly - Giao H a i la m o t

vi du, Tren suet chieu dai bo 3Q km dang bi xoi lo , de ngan da k h o n g cho mot nh.inh song nao d6 ra Mat khac, tram tfeh lo lung

oven b o c h a u th6 Ciing do qua trlnh nay

lam ngan di trac dien bo va tang cirong xoi

1 0khi n g u o n cung cap b6i tu suy giam Do

2 X a y d ljp v a d a o k e n h ,

nho dao hO~ICnao vet cac nhanh da tan d~

hanh dap thuy dien Hoa Binh chiern 53% tai

lu o n g ruroc c u a h e thong song Hong, x o i la

trang 30 narn qua co lien quan den dap song

v u e thirong n g u o n h~ thong song Hong rirng

tich nrng dau nguon bi phaZYXWVUTSRQPONMLKJIHGFEDCBA ( N g u y e ll M a u lt

C u o u g , /9 9 7 ). o d a i yen b o Cl'Sl+, trong so

tro n g ( P N H O llg I'd H P S U I I , / 9 9 3 )

day, co sir can bang giua rung ngap man bi

bang boi xoi cac cira song

bao v~ bo va tang cuong boi tu ( T D T h a n h

sinh thai do pha rung ng(lp m~n rat 16n V"i

co th~ tir do ngiroc vao thu do Ha NQi Sat! khi dao song, co nhirng bien d6i sau sac v~

dia phan Tien Lang nam trong khu vue bi de

rrieu man Ian doc song vao luc dia

3 P lu i r u n g v a t r 6 n g r u n g

Ca mroc ta co dien tich dat dai 33, 1 trieu

rung n o i chung d e u yeu v~ can clr khoa h9C, chua lam r6 duoc ba van d~ HI trong cay g"i ?

a dau ? va vao Itic nao ?

yen bien Cl'Sl-I her sire plurc tap voi nhfrng

ca quy mo va toe dQ nhirng bien d6i nay la

nay lam phat sinh V~ltang cuong cac tai bien

sinh va lam dao IQn tlnh b~n viing cua cac