Ứng dụng mô hình mike flood tính toán ngập lụt hệ thống sông nhuệ

Tp ch Khoa hc HQGHN, Khoa hc T nhin v Cng ngh 27, S 1S (2011) 37-43

37

ng dng m hnh MIKE FLOOD tnh ton ngp lt h thng sng Nhu - y trn a bn thnh ph H Ni

ng nh c, Trn Ngc Anh, Nguyn Nh*, Nguyn Thanh Sn

Khoa Kh tng Thy vn v Hi dng hc, Trng i hc Khoa hc T nhin, HQGHN, 334 Nguyn Tri, H Ni, Vit Nam

Nhn ngy 29 thng 4 nm 2011

Tm tt. Trong nhng nm gn y, bin i cc hin tng cc oan gy tn tht ln v ngi

v ca nhiu a phng cng nh nhiu lnh vc hot ng kinh t - x hi. Do vn qun

l l tr thnh trng im quc gia. Chnh v th vic xy dng bn ngp lt tr thnh mt

bi ton ht sc cn thit cung cp c s cho cng tc qun l l. i vi bi ton t ra, nghin

cu s dng MIKE FLOOD lm cng c m phng ngp lt h thng sng Nhu - y trn a

bn thnh ph H Ni. Trong , m hnh NAM c s dng xy dng chui s liu dng

chy t ma lm iu kin bin cho m hnh MIKE FLOOD. B thng s m hnh kt ni 1-2

chiu c hiu chnh v kim nh cho hai trn l ln nm 1984 v 2008 ti trm Ph L, kt hp

vi cc ti liu o c din ngp lt ca trn l lch s 2008. Kt qu cho thy m hnh m phng

vi chnh xc tng i cao th hin kh nng ng dng ca m hnh trong cng tc xy dng

bn ngp lt, bn tn thng cng nh cnh bo nguy c ng lt cho khu vc Thnh ph H

Ni. Bi bo c hon thnh vi s h tr ca ti nhm A, i hc Quc gia H Ni,

QGT.10-06

T kha: MIKE FLOOD, bn ngp lt, h thng sng Nhu - y.

1. M u

Din bin phc tp ca bin i kh hu

ton cu ko theo s bt thng ca ma ln, l

lt ... L mt lu vc c v tr chin lc trong

pht trin kinh t - x hi v an ninh quc

phng ca c nc, hn na lu vc Nhu y

li thng xuyn chu tc ng ca ngp lt khi

c ma ln. Do vic m phng bc tranh

ngp lt c t ra cp thit hn bao gi ht.

Chnh v vy nghin cu thc hin xy dng

bc tranh ngp lt chi tit cho khu vc theo cc

_______ Tc gi lin h. T: 0987761757.

E-mail: [email protected]

kch bn khc nhau s dng m hnh MIKE

FLOOD, phc v quy hoch, cnh bo, d bo

din ngp lt phc v cng tc ng ph nhanh,

cng nh c tnh thit hi do thin tai.

MIKE FLOOD l m hnh thu ng lc

hc dng chy kt ni 1&2 chiu, c kh nng

m phng mc nc v dng chy trn sng,

ca sng, vnh v ven bin, cng nh m phng

dng khng n nh hai chiu ngang trn ng

bng ngp l. N kt hp u im ca m hnh

1 chiu cho mng li sng (thi gian m

phng ngn) ln li th ca m hnh 2 chiu

(m phng chnh xc din ngp lt v trng

vn tc trn b mt ng bng ngp l), ng

.. c v nnk. / Tp ch Khoa hc HQGHN, Khoa hc T nhin v Cng ngh 27, S 1S (2011) 37-43 38

thi tng thch vi cc cu trc GIS thng

dng. Do MIKE FLOOD c c nhiu s

quan tm ca cc nh nghin cu cng nh c

nhiu ng dng trong thc tin Vit Nam v

trn th gii [1,3]

2. Gii thiu vng nghin cu

Lu vc sng Nhu-y nm hu ngn

sng Hng trong phm vi t 200 n 21020' v

Bc v t 1050 n 106030' kinh ng,

vi tng din tch t nhin l 7665 km2 (hnh 1),

vng nghin cu l Thnh ph H Ni vi din

tch 3344,6 km2, gm 9 qun, 18 huyn, 2 thnh

ph; dn s: 6.451.909 ngi (2009).

Sng y bt ngun t sng Hng thng

qua h thng phn cha l Vn Cc, Phc Th

chy qua H Ni, H Nam, Ninh Bnh v Nam

nh trc khi ra bin ng ti ca y.

Sng Nhu cng ly nc t sng Hng

qua cng Lin Mc T Lim, H Ni chy

qua cc tnh H Ni v H Ty ri vo sng

y ti Ph L, tnh H Nam.

Nm trn vng chu th sng Hng, lu

vc sng Nhu - y nm tri di theo phng

v tuyn t H Ni n Nam nh. a hnh lu

vc c s phn ho tng phn th hin r nt

theo hng Ty-ng v hng Bc-Nam.

Pha Ty v Ty Nam l a hnh i ni

chim khong 40% din tch, thp dn t ng

Bc xung Ty Nam ra bin v t Ty sang

ng. Phn ln l cc dy ni thp, cao

trung bnh 400-600m, an xen c mt vi khi

ni c cao trn 1000m nh Ba V (1296m),

i Thi (1198m), Vin Nam (1031m)

Din tch vng ng bng chim khong

60% lnh th, a hnh kh bng phng c

cao < 20 m v thp dn t Ty sang ng, t

Ty Bc xung ng Nam, b chia ct bi h

thng sng v knh mng chng cht. Vng

ng bng c th c chia thnh 4 khu vc c

c im khc nhau: Vng ng bng pha Bc,

Vng ng bng trung tm, Vng ng bng

pha Nam, Vng ng bng thung lng.

Thng lu sng un khc, hp v dc,

nhiu ghnh, nc chy xit, l nguy c to nn

cc hin tng xi l, l qut...Trung lu v h

lu c m rng, dng sng chy chm, kh

nng thot nc km dn n tnh trng ngp l

mi khi xut hin ma ln.

Hnh 1. S lu vc h thng sng Nhu - y v vng nghin cu.

Khu vc nghin cu ch yu l ng bng

c bi p bi cc dng sng vi cc bi bi

i, cao v bc thm, xen gia l cc vng trng

vi cc h, m..., vi cao trung bnh t 5

20m thp dn t Bc xung Nam, Ty sang

ng, nghing khng ln nn khi c lng

nc ln bt thng d xy ra ngp ng.


3. Gii thiu m hnh MIKE FLOOD

Dng chy trong vng ngp l l dng chy

2 chiu theo phng ngang, va c dng chy

tp trung trong cc mng li sng sui va c

dng chy trn trn b mt, do vy nu s dng

m hnh 2 chiu m phng qu trnh ny th

yu cu li tnh kh chi tit m t chnh

xc nh hng ca dng chy tp trung trong

cc knh, rnh. Mt khc, dng chy trn trn

b mt ch xut hin khi c mc nc trong

sng cao hn cao trnh b (hoc ), v th

gim thi gian v khi lng tnh ton c th

kt hp cc u im ca c m hnh 1 v 2

chiu bng cch kch hot m un tnh ton 2

chiu khi xut hin dng chy trn. M hnh

MIKE FLOOD thc hin cc kt ni gia m

hnh MIKE 11 (tnh ton thy lc mng sng 1

chiu) vi m hnh MIKE 21 (m phng dng

chy nc nng 2 chiu theo phng ngang)

bng 4 loi kt ni: a) kt ni tiu chun: s

dng khi mt nhnh sng mt chiu trc tip

vo vng ngp 2 chiu; b) kt ni bn: s dng

khi mt nhnh sng nm k vng ngp, v khi

mc nc trong sng cao hn cao trnh b th

s kt ni vi li tng ng ca m hnh 2

chiu; c) kt ni cng trnh (n): s dng cc

dng lin kt qua cng trnh; v d) kt ni kh

(zero flow link): l kt ni khng cho dng

chy trn qua [1, 4-6].

M hnh MIKE FLOOD c pht trin bi

Vin Thy lc an Mch (DHI) thc cht l

phn mm lin kt gia m hnh MIKE 11 v

MIKE 21 c xy dng trc . B m

hnh ny c th tch hp nhiu m un khc

nhau, nhng trong khun kh nghin cu ny

ch s dng m un RR (m hnh ma-dng

chy NAM) to dng chy bin u vo cho

m hnh thy lc mng sng (HD) kt hp vi

m hnh thy lc 2 chiu MIKE 21 [1, 4-6].

4. ng dng MIKE FLOOD tnh ton ngp lt lu vc Nhu - y trn a bn Thnh Ph H Ni

4.1. Xy dng c s d liu

- D liu a hnh: Bn s cao khu

vc nghin cu c xy dng vi phn gii

30x30m t bn a hnh t l 1: 25.000 kt

hp vi mt s cc s liu cao b sung thu

thp t cc ngun khc nhau [4]. Cc mt ct

ngang sng cho khu vc nghin cu thu thp

gm: 39 mt ct trn sng y, 26 mt ct trn

sng Nhu, 20 mt ct trn sng Tch v 12 mt

ct trn sng Hong Long.

- D liu kh tng thu vn: bao gm s

liu ma ngy, ma gi ti Lng, H ng, Ba

Th, Sn Ty, Hng Thi, Ph L cc nm 1984

v 2008; mc nc gi ti cc trm: Ph L,

Ninh Bnh cc nm 1984 v 2008; s liu trch

l lu lng ti trm Ba Th nm 1972, 1978.

Trn ton b vng nghin cu hin nay khng

c trm o lu lng, do vy lm c s cho

vic hiu chnh v kim nh m hnh ma-

dng chy (NAM), s liu lu lng trm Ba

Th nm 1972 v 1978 c s dng.

4.2. Thit lp m hnh MIKE FLOOD cho h thng sng Nhu - y

- Xy dng mng li thu lc mt chiu

Mng li thy vn khu vc nghin cu

c m t bng s thy lc bao gm sng

chnh l sng y vi chiu di 182 km, 39

mt ct, bin trn l trm thy vn p y,

bin di l trm thy vn Ninh Bnh, sng

Nhu vi chiu di 74 km vi 26 mt ct, bin

trn ly ti v tr cng Lin Mc, vo dng

chnh sng y ti ng ba Ph L. Ngoi ra,

mng thy lc cn bao gm mt s sng nh

sng Tch, sng Hong Long (hnh 2).


Hnh 2. S thy lc h thng sng Nhu - y.

- Xy dng mng thy lc hai chiu

Gii hn vng ngp h lu c xc nh

trn c s bn a hnh kt hp vi mt s

ti liu kho st cc trn l lch s nhm m

bo bao trm ton b vng ngp lt ti a. Bn

DEM khu vc nghin cu vi phn gii

30 x 30m xy dng trn c s dng lm

nn a hnh cho m hnh MIKE 21. Nn a

hnh ny c kt hp vi cc ti liu mng

li ng st, ng quc l v tnh l trong

khu vc. Khu vc nghin cu c ri rc ha

theo li phn t hu hn (FEM) vi khong

cch cc li l t 200 1000 m. V

1.000.000 m2, gc

nh nht 30o ton b vng ngp lt chia

27.846 6.678 3).

- Kt ni (Coupling) trong MIKE FLOOD

v

tnh ton trong MIKE 11 v MIKE 21,

chng trong MIKE FLOOD vi

trong 1.

4.3. Hiu chnh, kim nh MIKE FLOOD

tnh ton, m phng qu trnh dng chy

l trn lu vc bng m hnh thy vn, thy lc

cn thc hin cc bc hiu chnh v kim nh

b thng s cho m hnh tnh ton. Do bin u

vo ca m hnh MIKE FLOOD phi tnh gin

tip t ma bng m hnh NAM, do vy trc

ht phi kim nh v hiu chnh m hnh NAM

- Hiu chnh v kim nh m hnh NAM

Da trn tnh hnh ti liu o c lu lng

ti trm Ba Th trn l nm 1972 v 1978, hai

trn l c s liu lu lng thc o ny c

la chn hiu chnh v kim nh m hnh.

C th:Trn l 23/07/1972 n 20/09/1972 s

dng cho hiu chnh. Trn l t 28/8/1978 n

19/10/1978 s dng cho kim nh

Kt qu hiu chnh v kim nh NAM ti

Ba Th c th hin trong cc hnh 4 v 5. Ch

s Nash c s dng nh hm mc tiu trong

nghin cu, kt qu hiu chnh l 84.6% v

kim nh l 73,4% u t loi kh v m

bo yu cu cho cc bc tnh ton tip theo.

- nh gi kt qu tnh din ngp lt trn l

2008

Nhm mc tiu nh gi kh nng tnh ton

din ngp lt bng m hnh kt ni xy

dng, kt qu tnh ton c xut ra di dng

file ASCII, v x l bng phn mm ArcGis 9.3

nhm xy dng vng ngp lt vi su ngp

khc nhau thnh cc lp thng tin (layer) trn

GIS. T kt hp lp ranh gii hnh chnh c

sn, xc nh din ngp ng cc mc ngp su

cho ton vng. S liu tnh ton c so snh

vi nh v tinh c chp ngy 7/11/2011. Tuy

khng bt c thi gian xut hin nh l,

nhng phn no cng phn nh c din ngp

tnh ton ph hp vi thc t. Bn din tch

ngp lt tng ng vi trn l 2008 c

xy dng vi t l 1/25.000 v c minh ha

trong hnh 9.


Tn sng Mun Coupling trong Mike 21

y HD Bn 474

Nhu HD Bn 250

Tch HD Bn 304

Hong Long HD Bn 128

Hnh 3. S li phn t hu hn dng trong m hnh 2 chiu.

Hnh 4. Kt qu hiu chnh m hnh NAM.

Hnh 5. Kt qu kim nh m hnh NAM.

Hnh 6. Kt qu hiu chnh m hnh MIKE FLOOD ti Ph L (1984).

Hnh 7. Kt qu kim nh m hnh MIKE FLOOD

ti H ng (2008).


5. Kt lun

M hnh MIKE FLOOD ng dng tnh ton

ngp lt cho khu vc sng Nhu - y trn a

bn Thnh ph H Ni c hiu chnh v kim

nh vi kt qu nh gi theo ch tiu Nash

u trn 90%. Ring vi din ngp, so snh nh

v tinh chp ngy 7/11/2011 cho thy m hnh

m phng kh ph hp vi thc t.

Hnh 8. Kt qu kim nh m hnh MIKE FLOOD trm Ph L (2008).

Hnh 9. Bn ngp lt lu vc sng Nhu - y trn a bn Thnh ph H Ni.

iu ny th hin kh nng m phng tt qu trnh ngp lt trn lu vc nghin cu ca m hnh. Tc gi cng ang tip tc hon thin m hnh nh kho st b sung vt l, chi tit hn bn a hnh v cc loi ti liu khc hng ti vic s dng m hnh ny trong cng tc m phng l tn sut, xy dng cc kch bn l, nh gi tnh d b tn thng gy ra do ngp lt trn lu vc sng Nhu - y phc v cng tc cnh bo, d bo, phng chng gim nh thin tai.

Bng 11. Din tch ngp ln nht theo cc cp cao trong trn l nm 1984 v 2008 trn a bn Thnh ph H Ni

Mc ngp 0.1- 0.5m 0.5- 1m 1- 2m 2- 3m >3m

Din tch ngp (Km2) Trn l 1984 269.2 402.1 78.8 4.3 1.1

Trn l 2008 282.7 394.7 76.4 5.2 1.6

Ti liu tham kho

[1] Hong Thi Bnh, Xy dng bn ngp lt h

lu h thng sng Nht L (M Trung - Tm Lu -

ng Hi), Lun vn Thc s khoa hc, Trng

i hc Khoa hc T nhin, i hc Quc gia H

Ni, 2009.

[2] Nguyn Vn C v nnk, Bo co kt qu d n

KHCN cp nh nc: mi trng sng Nhu- y

phn I, H Ni, 2003.


[3] ng nh Kh, ng dng m hnh MIKE

FLOOD tnh ton mc ngp lt khu vc Bc

Thng Tn, kha lun tt nghip, trng i hc

Khoa hc T nhin, i hc Quc gia H Ni, 2009.

[4] ng nh c, Th nghim kh nng m phng

mc ngp lt m hnh MIKE FLOOD trn lu

vc sng Nhu - y, Bo co khoa hc, trng

i hc Khoa hc T nhin, HQGHN, 2010.

[5] Denmark Hydraulic Institute (DHI), 2007,

MIKE FLOOD Reference Manual DHI, 514 pp.

[6] Denmark Hydraulic Institute (DHI), 2007,

MIKE FLOOD User Guide DHI, 514 pp.

Simulation of flood inundation using MIKE FLOOD model in

Nhue - Day river system - Ha Noi city

Dang Dinh Duc, Tran Ngoc Anh, Nguyen Y Nhu, Nguyen Thanh Son

Faculty of Hydro-Meteorology & Oceanography, Hanoi University of Science, VNU,

334 Nguyen Trai, Hanoi, Vietnam

In recent years, variation of extreme events causes damage to human and properties of many local

region as well as eco-societies activities. Flood management problem is therefore a national focus.

Thus, flood mapping becomes the neccessary problem, provides a basis for flood management goals.

To this problem, the research applied MIKE FLOOD to simulation of inundation in Nhue Day river

basin within Ha Noi. In which, NAM is used to produce flow from rainfall and these simulated flow is

applied to a boundary condition of MIKE FLOOD. Observed headwater data of 2 historical flood

events, 1984 and 2008, at Phu Ly station and inundation area data of the flood event in 2008 are used

to optimize the parameter set of 1-2 dimensional model. The results indicated that this model achieves

a fairly high accuracy, reveals ability to apply to inundation vulnerable mapping as well as flood risk

warning for Ha Noi. This study is completed with the support of A project group, Vietnam National

University, QGT.10-06

Keywords: MIKE FLOOD, inundation, flooding map, Nhue - Day river.

Ứng dụng mô hình mike flood tính toán ngập lụt hệ thống sông nhuệ

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