Nghien cilu - Trao doi
^Tlem nang va giai phap khai thac ben vuhg nifofc dutfi dat tinh Ha Giang
O ThS. PHAM BA QUYEN
Uin ddn Quy hopch vi Diiu tra Tii nguyin nudc miin Bic NCS. TRIEU BUIC HUY
Tmng tim Quy hopch vi Diiu tra Tii nguyin nudc Quic gia
N
udc dudi dat tlnh Hi Giang li nguon tii nguyin vd cung quy gii.Kit qui dieu tra, dinh gii TNN dudi dit tren toin tlnh chd thiy, trO lupng tiem ning khding 1.738.813 nf/ngiy. Chiiu siu phin tm NDD khic nhau php thupc rat nhiiu vio die diem DCTV, mi/c xim thi/c dia phUdng nen vipc ip dpng cic phUdng phip khai thic, stjr dpng cung hit sure khd khin. E>i bio dim khai thic, SDN bin vCmg, can cd giii phip md hlnh khai thic nudc thich hpp vdi tdng diiu kipn khic nhau. Kit qui nghien cdu cung da di xuit mpt sd giii phip khai thic bin vUng pht^c vp cung dp nudc tren dja bin tlnh Hi Giang.
B$c dllm dia chit thiiy vin Kit q u i ting hop, phin tteh cic tit ll^u dilu tra khio sit trin dja bin tinh cho thiy, trin dia bin t!nh H i Giang cd ting s i 16 ting chOa nudc, trong dd, c6 1 ting chOa nudc 16 hing v i 15 ting chOa node khe nOt, khe not karst. Trong dd, cic ting chOa node khe nOt karst c6 di^n phin bd rpng, khi ning ChUa nudc tU trung binh din gliu l i cic ting chUa node c-p, Eg^, E3 v i d-i. Cic ting chOa node khic hiu hit l i cic ting nghio nude. Cic phOc he ngheo nude hoic khdng ChOa nudc chu yiu l i eic d i macma xim nhip cua cie phUdng h^ nhu Nim But, Bach Sa... phin b l rii ric trin dia bin tJnh.
Chat lupng nUdc dudi dit Trin dia b i n tlnh H i Giang, c i c loai nude thUPng tO sieu nhat
d i n node r i t nhat. Node siiu nhat cd dp t i n g khoing hda <
0,2g/l chiem 86%. phin b l trong cic ting chUa node d^\ di.2, £2^, E2', £3... ChCi y i u t i p trung d phia Ddng v i trung tam tlnh H i Giang.
Node rit nhat cd dp ting khoing hda to 0,2 g/l d i n D,5g/I chllm khoing 14% dldn tieh vung nghiSn cOu t^p trung 6 phia Nam - T i y Nam tlnh v i trong eic ting ehOa node d , ' , d,=, d,.2. i^', k.
Node ngim thupc loai Biearbonat calel cd mat h l u h i t trong cae t i n g ChOa node, k i o dai theo phuong to Ddng sang T i y v i tO phia B i c d i n phia Nam. Loai node Biearbonat calei-magle t§p trung phin b l thinh nhOng dldn nhd to v i i true c i y s i vudng trong c i e t i n g chOa node d , ' , d l ' d,.2, E2^ sj' v i n i m r i i r i c
trong t o i n t?nh, chllm khoing 25%. Loai node Biearbonat caici cd mUc dp p h i n b l rpng hon chllm khoing 63% di$n tich vung nghiin cOu, da phin t$p trung tai e i c t i n g chUa nudc d,', d 1.2. E2''. e2^ ^3' *V' ^1 ^ ^ Phfa Bic - Ddng B i c v i p h i n trung tim tlnh H i Giang. Loai node Biear- bonat catci-natri t i p trung d cic t i n g chOa node d^\ di^, E^', £2' v i c i c thinh tao nghio node magma x i m nhip, phin b l dl phia T i y - T i y Nam, thupc huyOn B i c Quang, Quang Binh, chu y i u n i m d huy^n Hoing Su Phi v i Xin M i n .
Dinh g i i trO lupng tilm ning nudc dudi dit
TrO lupng tilm n i n g NDD bao g I m c i c thinh p h i n triji tuong ddng tu nhidn. trO lupng 3 6 T6I nguydn vd Mdi troong | Ki 2-TMlig 10/2011
tinh d^n h6i, m6t phSn trO iupng tlnh trpng li^c, trfl luqng cu6n theo.... dagc xdc dinh bang c6ng thflc:
Bdng ^. He so trQiQpng d0ng tpnhidn
= e „ + ^ H
^a.
Trong do:
Q\^i trfl Iflong tiem nSng NDD, mVng
Otp; trfl Ifldng dong tfl nhien NDD, mVng
Vjh- trfl Ifldng ttnh dan hoi NDD, m^
Vji: trQ Ifldng tTnh trpng Iflc NDD, m^
a: he s6 xdm pham v^o trO Ifldng ttnh trong Iflc tfl nhien (l§'y b&nq 30% dd'i vdi cac t^ng chfla nfldc khdng ap vd 0% d6i vdi tSng chfla nfldc co ap Iflc)
Q^t: trilf Ifldng cu6n theo, m^/ng
t thdi gian khai thac, thfldng dfldc l^y bang 27 ndm (10* ngiy).
D^ xac dinh trfl Ifldng ddng tfl nhi6n cua cac t^ng chfla nfldc tr&n dta ban tinh, sfl dyng phfldng phcip do thuy vSn dfldc quy d6i ve gia trj t6'i thilu tan suat 95% phu hop vdi myc dfch khai thdc SDN ndn c6 gia trj th^p Kdt quh tinh trO Ifldng ddng tfl nhidn theo phfldng phdp do thuy vSn se dSy du hdn, vi c6 chudi quan trSc thfldng rllt d^i, cac tram quan trSc dfldc bd tn theo di^n va dgi di^n cho tSt cd c^c t^ng chfla nfldc ndn dfldc SLf dgng de tinh trfl Ifldng khai thac tidm nSng cua cSc t^ng chfla nfldc.
Trfl Ifldng khai thac ti^m nSng dfldc tinh theo cdng thflc:
Q j N = a. Qe (mVng) Trong dd: a- \d he s6 trfl Ifldng d0ng tfl nhidn, ISiy theo gia trj md dun ddng ngSm trung binh
M n a
0 , 5 - 1 0,4
1 ^ 2 : 2 ^ 3 0,5 0,6
3 ^ 5 0,62
5 - 7 0,67
> 7 0.7 Hinh 1. Ban do tiim nang nudc dudi di't tinh Hi Giang
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cua t^ng chfla nfldc, theo VC.Ko- valevski:
Mn0,5-r 11 ^ 2 2 - r 33 ^ 5 5 ^ 7> 7^0,40,50,60,620,670,7
Theo ket qu^ tinh toan trfl Ifldng dpng tfl nhidn cua cac tang chfla nfldc trdn dja ban toan tinh cho thS'y. trfl Ifldng tilm nang NDD khoSng 1.738.813 m^/ngay, trong dd tang chfla nfldc co trfl Ifldng tiem nang Idn nhat la tang chfla nfldc d-) vdi 516.918 m^/ngay. T^ng chfla nfldc o-| co trfl Ifldng tiem nang nhd nhat vdi 2.302 m^/ngay.
Gidi phap khai thac nUdc dfldi dat tinh Ha Giang
Giai phdp khai thdc nude bdng giing khoan
Khai thac NDD bang cac gieng khoan da dfldc ap dyng d nhieu vung nui cao tinh Ha Giang Cfl the, nam 2012, tlnh da giao cho Sd TN&MT tid'n hanh didu tra thflc trgng trfl Ifldng va ch3t Ifldng cac gieng khoan tham do tfl cac giai dogn trflde trdn 2 huypn Dong van va Meo Vgc (khdng tinh cac l6 khoan BTNMT t n i n khai 6 Meo Vgc). Kdt quS da xac dmh dfldc tfl 11 l6 khoan cho thay, Iflu Ifldng khai thac la 1.500 m^/ngd. Trong dd, trung Xdm thi Ira'n Dong Van c6 t h i xay dflng trgm ca'p nfldc cdng suat 1.100 mVngd, trung tam xa Niem Sdn - Meo Vgc cd t h i xay dflng trgm cong sulit 400 m^/ngd. Nam 2012 tai khu thj tr^n Ddng Van da tiln
Toi nguyen v6 Moi truong | Ky2-TlltlHlHI/2016 VI
h a n h khoan 2 l6 khoan K T D V 1 (Iflu Ifldng dgt 4 0 0 mVngay) va K T T L 2 (Iflu Ifldng dgt 5 0 0 mVngay) c d dfldng kfnh 141 m m d l tien hanh xSy d f l n g trgm khai t h a c nfldc tap trung c o n g sucit 300 m V n g d d l ca'p nfldc cho thi tr^n (trgm c ^ p nfldc nay do Lidn doan Q H & D T T N N mien Bac thi cdng da hoan thanh nam 2013 va ban giao cho dja phfldng quSn ly, v a n hanh).
Khai thdc nuOc bdng gieng dao Hinh thflc c a p nfldc b i n g g i i n g dao chi phu hdp vdi nhflng v u n g c 6 mflc nfldc n g ^ m t h ^ p , thfldng la nhflng khu vflc ven s d n g , v e n sudi, cac thung lung.
Tuy nhidn, do xay dflng khdng b&o d d m , bdo quSn con s d sai trong qua trinh s f l dgng ndn n h i l u g i i n g cd ch^t Ifldng k d m . Gieng ddo cd dfldng kinh tfl 0.8 ^ 1,5 m, c h i l u sau g i i n g tfl 4 -=• 7 m d i n 9 -r 15 m. D I bdo ddm vd sinh g i i n g phdt c d thdnh ndp ddy, san g i l n g phai xay ddc va cd ranh thoat nfldc b i n . Nfldc gidng dfldc dfla Idn trdn m$t ddt bdng cac logi bdm tay khac ho$c bdng gdu muc.
Khai thdc nudc tUmpch ip 6 Vidt N a m , hinh thflc khai thac nfldc tfl cdc m g c h nfldc da dfldc cdc dd thi Ddy Id mdt hinh thflc rdt ddn gidn khi chi can thu gom tgo mdt m d thu nfldc vdi kich thflc nhd 6 nhflng ndi c d m g c h nfldc ngdm hodc 16 thidn. Mo cd t h i lam bdng da hoac ggch xay.
Ngfldi d a n c 6 t h i s f l d g n g ngay tgi chfi ( t d m , giat, c h o gia sue udng n f l d c . ) hoac dfla nfldc ve n h d b d n g 6 n g nhfla P V C , dng H D P E hoac I n g tre ( m a n g Idn) ddn nfldc tfl m d v l b l hay Iu ho$c mdt s 6 h6 treo do khdng co n g u o n sinh thuy tgi c h 6 da dan nfldc tfl m g c h Id v l c u n g c d p nfldc c h o cdc hd treo n h f l d hd
3 8 Tdi n g u y d n v a M d i t r u o n g I
treo P d V i T h f l d n g . h i t r e o P d i L u n g 6 M e o V g c .
Khai thic nddc tUhang d^ng d Ha Giang, hdu h i t cdc dia phfldng c d hang d d n g c h f l a nfldc d i u s f l dgng bdm hut de khai thac.
Ngay tgi cao n g u y d n D d n g V a n cac dja phfldng da sCf d g n g b d m d l hut nfldc trong cdc h a n g d d n g ndm trdn do cao 1400 - 1500 m.
Bdm hut nfldc co thudn ldi id d l thi cdng va vd'n ddu tfl ban d d u n h d . Gidi phap nay ap d g n g c h o cac khu vflc cd phan bo nfldc n g l m karst tfldng ddi gan mat dat hoac c d nfldc n g a m hang d d n g . nfldc karst thuy v a n gdn vdi khu vflc s f l dgng. Cdc ky thudt khat thdc g d m : Bdm hut c d t h i dp d g n g cho h l u het cdc d i i m Id nfldc karst 6 d g n g nfldc hang dpng, nfldc karst thuy v d n . Ky thudt bdm hut hidn nay cho phdp bdm hflt sau tdi 200-300 m. Mpt trong nhflng c d n g n g h d hien dgi khai thac nfldc t f l hang ddng dang dfldc dp d g n g 6 v u n g cao nguydn da D d n g Van la c d n g nghd bdm PaT ( P u m p as Tur- bine). Cdng nghd bdm PaT dfldc t h i l t k l va flng d g n g v a o n h i l u d i l u kidn khac nhau, phg thudc chinh vao d^c d i l m c u a tflng khu vflc. Tuy nhien, c d n g nghp nay c u n g cd rui ro Id d ^ c d i l m b i l n c h u y i n nhanh cua nfldc khu vflc karst, ddng nang d o n g ehdy cung nhfl riji ro va chgm m g n h c u a cdc khoi tdng cung n h f l sdp hang...
Ket ludn
Chdt Iflpng N D D trdn dja bdn tinh Ha Giang tfldng d l i t i t , hodn t o a n d d p flng c h o nhu c d u sinh hogt. s d n xudt. C h d t Iflpng nfldc nfldc t h f l d n g tfl s i d u nhgt d i n nfldc rdt nhat. Nfldc sieu nhgt c d d d t o n g k h o a n g h d a <. 0,2g/l c h i e m 8 6 % , logi hinh hda hpc nfldc chfl y i u la Biearbonat calei vd Biearbonat calci-natn
Ky 2 - T M m 0/2016
T r f l Iflpng t t i m n d n g NOB t r d n dja b d n tinh khodng 1.738.813 m V n g d y . t r o n g d6.
t d n g c h f l a nfldc c d trfl Ifldng t i l m n d n g tdn nhdt Id t d n g c h f l a nfldc d i v d i 5 1 6 . 9 1 8 m^/ngdy. Tdng ehfla n f l d c o-| c 6 trfl Ifldng t i l m n d n g n h d nhdt vdi 2.302 m^/ngdy.
D d i vdi cdc h u y $ n v u n g cao D i n g v a n , M e o V g c , Y d n Minh v d Q u d n B g hinh thfle khgi thdc nfldc e d p nfldc eho trung tdm thj trdn Id khai t h d c b d n g cdc g i l n g k h o a n v d khai t h d c nfldc trong hang d d n g , vdi cdc bdn Idng phdn b d d d n c f l k h d n g t $ p trung hinh thflc khai thdc Id cdc m g c h Id ddn v l SLf d g n g . Dd'i v d i nhflng khu vflc p h d n bo h a n g karst ngdm c6 t h i nghidn c f l u dp d g n g hlnh thflc khai thdc b d n g c d n g nghd PaT.
T A I L I E U T H A M KHAO 1 Nguydn V a n Ldm vd nnk, 2010. D l tai NCKH cdp nhd nfldc:
"Nghidn cdu sp hlnh thdnh. phdn b6 vd dS xuit h$ phuang phdp ddntt gid vd sQ dung tdi TNN ngdm vung karst Ddng Bdc Vi$t Nam" ma s6 KC.08.19/06-10
2. Phgm Ba Q u y i n vd nnk.
2016. D^ tai cdp Bd "NghiSn cdu gidi phdp khai thic. sCf dung tidn vQng ngudn nudc t^i cdc vung nui cao karst Ddng Bdc Vi$t Nam. Ap dvng thd nghi$m t^i vung cao nguydn cM Ddng Van"ma s i 2015.02.06.
3. Li6n doan Q H & D T TNN m i l n Bdc. 2016. DiSu tra l$p quy hoach bdo vd TNN tlnh Hd Giang giai do^n 2015-2020.
4. Lidn doan Q H & D T TNN m i l n Bdc, 2010. Bdo cdo Didu tra ddnh gid ngudn NDD khu vQc trung du miSn nui Bdc 80 • Tlnh HA Giang, ndm 2010.
5. Vu Thanh Tam (2004^, De- velopment of a method detemind aquifer parameters by single pump- ing well in fractured aquifers. Geo- logical journal u
