• KHOA HOC CONG NGH£ •
NGHIEN CLfU, DANH GIA TRO' LU-aNG VA CHAT LU-ONG N W C
TAI H 6 CHLFA Nuac Ni/ac TA VAI Dt CAP CHO SINH HOATTHS.NCS. D^NG XUAN THlTdNG, TS. N G U Y £ N P H C DUVfeN, THS. DAO QUANG LINH, KS.HOANG V A N H i t U
Viin Ky thugt vd Cdng ngh$ Moi tru&ng - Liin h i§p cdc Hpi Khoa hpc vd Ky thugt Vift Nam
THS. NGUYfeN HUY THiNH
Vifn Dia chat - Vifn Han ldm Khoa hpc vd Cdng ngh0 Vi$t Nam KS. NGUYEN BINH VINH
Vifn Tdi nguyin nu&c vd moi tru&ng
Tom tdt: Ho ehua nu&c Td Vdi ndm tren dia bdn xd Nggc Du&ng thudc thdnh phd Hd Giang, tinh Hd Giang. Luu vuc sudi Td Vdi dugc xdc dinh Id xdp xi 30 km . Sudi Td Vdi gdm 3 nhdnh sudi ehinh:
nhdnh sudi ndm &phdn Nam luu vuc, nhdnh sudi phdn gOea luu vice vd nhdnh sudi &phia Bde luu vi^c.
Ldng hd ehua dugc xdc dinh chimg 3,6 ha. Dung tich trung binh hd chua vdo miia Mid Id 76.090 m vd vdo mita mua la 87.141 m^. Lugng nu&c mua bd cap ve hd Id 300.000 m vdo mua khd, cdn vdo miia mua la 1.620.000 m^. Lugng nu&c hd cd thi ddp iing muc dich thuy lgi cho ddn bdn thdn Td Vdi. Ngodi ra, chdt lugng nu&c hd ed thi ddp iing la ngudn nu&c sinh hogt (sau khi dugc xie ly) cho khodng 1000 bd ddi cua Trung Dodn X vd Tru&ng qudn s{r, thudc Bd ehi huy qudn su tinh Hd Giang, citng 3500 ngu&i dimg cua todn bd ngu&i ddn xd Nggc Du&ng (thdnh phd Hd Giang).
Abstract: Ta Vai reservoir is located in Ngoe Duong commune (Ha Giang city, Ha Giang province). The Ta Vai catchment is approximately 30 km^. The Ta Vai Stream consists of 3 main streams: the stream is located in the southern part ofthe catchment, the middle ofthe catchment and the northern part ofthe catchment. The reservoir area is defined as the water surface area from the elevation of the outlet to the upstream of the Ta Vai stream and reaches about 3.6 ha. The average volume ofthe reservoir in the dry season is 76,090 m and in the rainy season is 87,141 m . The amount of rainwater added to the reservoir is 300,000 m^ in the dry season, while in the rainy season it is 1.620,000 m^. The reservoir water can meet irrigation purposes for the villagers in Ta Vai village. In addition, the quality ofthe reservoir can be used as a source of drinking water (after treatment), for 1,000 troops of the Regiment, the Military Academy, under Ha Giang Military Command and 3,500 users ofthe whole population of Ngoe Duong commune (Ha Giang city).
1. 0j\T VAN D E Giang, cimg ddn bdn xung quanh, dap Td Vdi Ha Giang Id tinh mien nui Tay Bde, ludn trd thdnh d|p da muc tieu.
hiing chiu de dga thudng true la thieu nude cho 1.1. M\ic tieu nghien ciiu:
sinh hogt, ddc bi$t Id miia khd. Ddp nude Td Bdi bdo nay nhdm tdi hai myc tieu sau:
Vdi dugc xdy dyng vdo ddu nhung ndm 2000, Nghien cuu, danh gid luu lugng ddng vdi chiic ndng chfnh la thuy lgi. Ngdy nay, diing chdy b^ cap vd hd, tir dd tinh toan tru lugng trudc van de fade thiet cdn cung cdp nude smh nude cda ho chiia Ta Vdi;
hogt cho dgn vj bd dgi (Trung doan X, Trudng - Ddnh gid chdt lugng nude hd chiia Ta Vdi qudn su, thuOc BO chi huy quan s\f tinh Ha dung cho myc dich sinh hogt.
100 TAP CHfTAl NGUYEN N U O C 5(54-2017
• K H O A H O C C O N G N G H E • 1.2, Gidi thifu v^ v i n g nghien cihi
^ Vung nghidn cdu (luu vyc sudi Td Vdi) nam cdch trung tdm thdnh ph6 Ha Giang chung 1,5 km theo dudng chim bay vd phia Ddng, tren dia bdn xd Nggc Dudng (Tp. Ha Giang) vd mgt phan nhd xa Kim Thach (huyen Vi Xuydn). Toan bO di?n tich luu vyc suoi Td Vai rOng khodng 30 km^.
1.2.1.Dia hinh luu vuc sudi Td Vdi: Luu vyc Td Vdi ndm trdn khu vuc cd dia hmh xdm thyc bde mdn, phdn cdt mgnh me, do cao tu 102 m (cua sudi chdy vdo sdng Mien d phia Tdy) ddn 1181 m (dinh nui Da Ddu d phia Ddng). Vay quanh luu vye Id cdc day nui cao: phia Tdy la niii Md Neo, cao 764m; Phia Bde - ndi Ban Tuy cao 315m; Phia Ddng - day ndi Khu6i Vdu cao 746m, nui Da Ddu - 1181m; Phia Nam - dinh Kim Thanh cao 612m. Ldng sudi chinh (cimg Id dudng day dia hinh) chdy tren dO cao trung binh 140 ddn 170 met.
1.2.2. Thdy van: He th6ng sudi Ta Vdi gom 3 mang ludi suoi chinh phdn bd d phia nam, phdn giiJa va phia bde luu vyc
-+ Mang ludi suoi ldn nhat trong 3 sudi ndm d phia Nam cua luu vuc, cd tdng chidu ddi chimg
13,5 km, bdt nguon td phdn Ddng Nam cd do cao nhdt luu vyc. Sudi chdy tu Ddng Nam xuong Tdy Bde vd ldng hd Td Vdi, qua cdc bdn ddng due ddn cu sinh sdng Id bdn Hda Binh, ban Thdm, bdn Chang. Tren dudng chdy vd hd, ddng su6i chinh ndy thu nhdn thdm nude cua 6 nhdnh sudi nhd khac cimg do vdo.
+ Mang ludi sudi thd hai ndm d phan giiJa cda luu vyc ddi khodng 4,5 km, bdt ngudn tir phia Ddng chay vd phia Tdy hgp ehung vao long hd. Noi suoi chdy qua hdu nhu khdng co dan cu sinh sdng.
+ Mgng ludi sudi thd ba ndm d phia Bde cua luu vyc vdi chieu ddi khoang 3,5 km. Sudi bdt ngudn tu phia Ddng chay vd phia Tdy chimg 1 km, roi chdy ngo^t vd phia Nam vd do vao long hd.
1.2.3. Khi hgu: Trong cdc ydu td khi hgu nhu: do dm, nhi|t dO trung binh, lugng boc hoi, sd gid ndng theo thdng,... thi lugng mua ddng vai trd quan trgng nhat trong cung cap nude cho khu vyc nghien cuu. Sd lieu lugng mua do tgi tram Hd Giang gan ngay sat khu vue nghidn cdu, ddng thdi phan dnh ehinh xac lugng mua roi tren luu vuc.
Bang 1. Lirgng m u a cdc thdng trong ndm tai Trgm Ha Giang (Don vj: mm) [4]
T.l T.2 T.3 T.4 T.5 T.6 T.7 T.8 T.9 T.IO T. 11 T. 12
2011 20,8 13,1 101,1 78,1 232,7 423,5 314,8 199,5 229,2 142,4 37,9 15,8
2012 42,5 22,6 46,5 58 429,3 315,9 862,5 243,7 251 126,6 44,6 26,4
2013 61,3 29,2 32,7 26,9 165,5 215,4 1.066,9
417,0 115,9 64,0 13,7 109,0
2014 30,8 11,9 78,1 168,5 150,2 239,6 570,6 352,2 308,9 24,6 176,1
15,2 2015 57,7 16,9 60,4 58,9 188,3 358,3 388,6 429,2 438,5 133,5 187,5 64,5
2016 52,4 5,5 33,2 127,0 313,3 203,9 303,4 261,7 142,1 115,7 128,4 35,0
T.binh thang cua
6nSm 44,2 16.5 S8,6 86,2 246,5 292,8 584,5 3173 247,6 101,1 9S,0 443
T. binh theo miia cua 6 nSm
Mua kho:
40,9
Mfla mua:
246,7
T. binh theo namc0a6
nSm
178,1
TAPCHlTAlNGUYeNNU(3CS64-2017 101
• K H O A H Q C C O N G N G H ^ • 2. PHlTONG PHAP NGHIEN CUtJ VA
KET QUA
2.1. Phirong phdp xac dinh dien tich liru vyc suoi Ta Vai
Dd xdc dinh didn tich luu vyc, chiing tdi dp dyng phuong phap phd bien va dam bdo do chinh xde cdn thidt la ung dyng hd phdn mdm GIS, trong dd chu ydu Id trinh ArcGIS 10.5, Glogal Mapper 18.1, MAPINFO 10, Micro Station 8, vdi trinh ty thuc hign cdc budc nhu sau:
- Sir dyng file anh vd tinh, phdn giai 0,15m, dugc ndn chinh da diem tbeo he tga do VN2000, tuang duang ty lg 1:50.000.
- Sd dyng ban dd dia hinh khu vuc nghidn cuu: cdc td Tdng Ba, td Ha Giang ti Id 1:50.000.
Tham khdo cac mdnh bdn dd sd dia binh vd sd dyng ddt cdc xd Nggc Dudng, Kim Thach, t^ le 1:10.000 [12].
- Sd hda he thdng thuy van.
- Xac dinh dudng dinh - dudng phdn thuy theo ban dd dia hinh va md hinh sd dg cao (DEM) d tyle 1:50.000.
- Xac dinh poligon luu vyc Td Vdi vd tinh toan di?n tieh poligon nay xap xi 30 km^
(3000 ha).
2.2. Xac djnh kich thirdc va dien tich Idng h^ Td Vai
Di?n tich cua ho Td Vai duge xac dinh tuong ty nhu xac dinh di$n tich luu vyc sudi Td Vdi, vdi eae kich thudc the hign tren Hinh 3. Dien tieh long hd Ta Vdi bdng tdng dien tich long hd chinh (dong ehinh sudi Ta Vai), cgng vdi di?n tich long hd phy (ndm d phia nam cua than dap chinh), cgng vdi difn tich ldng tat ca cae nhdnh sudi nhd khac c6 trong luu vyc:
S(TdVai) =; 0,036158 km^ ( - 3 , 6 ha) 2.3. Xdc dinh dg sdu cua Idng hd chda Ta Vai: De xac dinh dg sdu trung binh cua hd tai ngay thdn ddp chinh, chiing tdi dd dung thuyin va qud rgi de do cdc diem khac nhau trdn khdp long ho chinh, rdi tinh trung binh cOng. Gid tri trung binh do sau long ho Id 2,1 m.
2.4. Khao sat va do lini lugng ddng chay cic suoi trong lun vurc Ta Vai:
Lim tde ke di?n GP - 55 da dugc ddng do luu t6c cdc nhdnh chi'nh cua hd thdng sudi Ta Vdi vd dugc kidm dinh trudc khi do.
m
1 ^^^ B ^ B ^ ^ ^ 1 3a V nh^llOm 1
1150 m ^ B
Hinh 3. Ldng hd sudi Td Vdi v&i cde kieh ihu&e Chiing tdi da tien hanh do luu tde va tinh toan luu lugng ddng chdy d tdt ca cdc nhanh sudi chinh tgi phan Nam, phdn giu:a vd phdn Bde cda luu vyc vdo mda khd vd mda mua.
Phdn bd cdc diem do dugc the hi^n trong Hinh 4, dudi ddy.
2.5. Tinh todn Ivgng nude tham 0si ddng m^t (bo c^p cho suoi chay ve ho chua) vao mua.khd
- Trudc hdt, ta tinh lugng mua trung binh cua 4 thdng mua khd (tii thang 12 den thdng 3 ndm sau) ciia 6 ndm lien tyc la: 40,9 mm (xem Bang 1).
- Sau khi tham khdo cdc cdng trinh nghidn ciiu d cdc vimg tuang ty d trong va ngodi nude [1, 2, 3, 4, 5, 6, 7, 8, 9 va 10], da p h k lugng mua sau khi rai xudng dit thi ngam vdo dat tao thanh nude dudi ddt, ehi lugng nhd khodng 20 - 30% lugng nude mua (sau khi dat no nude) tham gia vdo ddng mdt, bb cap cho mgng ludi sudi trong luu vyc (30 km^). Tgi vimg nghidn cuu chi khoang 10 mm, (trong 40,9 mm) lugng nude mua vao mua khd, cd the bd c§p cho ho Ta vdi.
V4y lugng nude bd cap vdo miia khd cho hd la: Vbc kh6= 0,01 m x 30 x 10* m^ = 300.000 m^
102 TAPCHfTAlNGUYeNNa(3C564-2017
• KHOA HOC CONG N G H f • (Vbc khs la lugng nuoc bd cap cho h6 Ta Vai vao
mua kho).
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[osicaiurant
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•««"•. 1 ) ^ - ^ I I . ' M " , ' " ' I />.a^j^^^^__^0Mlngl3>u«mniM 1 jp..i™_i„i,jX\ ^ ^ D" tHiiBBil*. 1
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Hinh 4. Sa dd tdi lieu thue ti cdc diem do luu lugng ddng chdy mgng lu&i sudi
luu v{cc Td Vdi Tilf: 1:50.000 2.6. Tinh toan luQiig nirdc tham gia ddng mat (bo cgp cho suoi chay v l ho) mua mua
Tuong ty nhu tinh todn lugng nude bd cap vdo miia khd, d phdn trdn, [thay \ i 10 mm. Id 54 mm (trong 246,7 mm) lugng nude cd the tham gia ddng mat], nen lugng nude bd cdp eho hd vao mua mua se ldn ban miia khd, Id: Vbc mua = 0,054 m X 30 X 10* m^ = 1.620.000 m^ (Vbc m«a:
lugng nude bd cap miia mua).
2.7. Tinh toan tru lugng nirdc trong ho chira vao mua khd
Vi do (gde) nghidng dia hinh dudng ddy cua long hd Ta Vai nhd (0,3%), nen ed the xem cdch tinh the tieh nude trong hd xdp xi bdng di?n tich Idng hd, nhdn vdi bd ddy ldp nude trong hd. Trii lugng nude trong hd vdo miia khd la: Vkha "=2,1 m X 36.156 m^ ~ 76.090 m^ (Vu,a la tri^ lugng nude trong hd vdo mua khd)
2.8. Tinh toan tru- lugng nude trong ho chira mua mua
Lugng nude trft trong ho vao miia mua la lugng nude xde djnh bdng dg sdu cua hd tu day
hd len m|.t nude hd vdo mua mua (m), (thudng Id cao han cdt cua xd tran) nhan vdi tdng didn tich ldng hd (m^): V„„„ = 2,41 m x 36.158 m^
Vmua ~ 87.141 m^ (Vmira Id trii lugng nude trong ho vdo miia mua)
2.9. Chat lugng nude suoi Ta Vai Dd nghidn edu, ddnh gid chat lugng nude tren cdc nhanh sudi do ve hd, ciing nhu tai hd Ta Vai, 09 mau nude miia khd vd 09 mau nude miia mua da dugc ldy tgi cung cdc vi tri tuang dng.
2.9.1. Phdn bd cdc diem l^y mau nude mat vimg nghien ciru:
Trong hai mua: miia khd vd miia mua vda qua, chung tdi da tien hdnh ldy mau nude mat vd phdn tieh todn bg sd mau tren dia bdn nghien ciru, gdm: 09 mau miia khd vd 09 mau mua mua, dugc Idy trung tai cac dja didm sau, (xem Hinh 4):
(1) Dau ngudn sudi phdn Nam luu vyc (gdn trudng tieu hgc Kim Thgch, xa Kim Thach - Vi Xuyen); (2) Didm hgp luu d ngd ba sudi ddu tien phia trudc dap (D.H); (3) Nhdnh re dau tien chdy vdo sudi Td Vai; (4) Sudi Td Vdi, gida dap thuy lgi; (5) Suoi Td Vdi, tgi Bdn Chang, xd Kim Thgch, huyen Vi Xuydn (D.12); (6) Sudi Ta Vdi, cda xd tran thdn dap (D.S); (7) Sudi Ta Vai, nhanh sudi phia Tay Bae ddng ehinh (nhanh thd 2); (8) Sudi Td Vai, diem hgp luu thu hai trudc thdn ddp (gdn D.16, D.17) vd (9) Tgi mucmg thu;J' lgi sau than dap.
2.9.2. Nhdn xet vd chdt lugng nude vimg nghien cdu (dp dung QCVN 08MT:
2015/BTNMT) [11]:
Sd lugng 18 mau nude mdt lay theo 2 miia vd dugc phdn tieh tai Phong thi nghiem cua Vi?n Ky thugt va Cong nghd Mdi trudng (duge edp VILAS 995 cua BO KH vd CN, chung nhgn VIMCERTS 112 eua Bg TN vd MT), cho ket qua (ddi chidu QCVN 08-MT:20l5/BTNMT [ddi vdi cot Al - Su dung cho myc dich cdp
TAP CHl TAI NGUYEN Nt/dC 5(54-2017 103
• KHOA H Q C C O N G N G H j : • nude sinh hogt (sau kbi dp dung xd ly thdng
thudng)], nhu sau:
(-) BOD5"'' vugt Quy chuan (QC) trong khoang tir 1 den 4 Ian; (-) COD*"' vugt QC trong khoang tir 1 din 2,7 ldn; (-)T6ng chat rdn lo Idng: vugt QC gdn tir 2 ddn 5 lan;
(-) Nitrat (NO j'ti'nh theo N)**", vugt QC tir khdng dang kd den 2,5 Idn; (-) Nitrit (NO2' tinh theo N)^''*'' vugt QC khdng dang k l ; (-) Chi tidu Mn ''-''*: vugt QC tir 1,3 din 3 \hi; (-) Fe '^'"^ : vugt QC khdng ddng kd; (-) Tdng ddu, md**'* phdt hi?n d mOt hai mau vugt QC td 1 ddn 2 ldn; (-) Coliforms*^* cbi phdt hidn d 04/18 mdu vugt QC td 2 ddn 4 ldn vd (-) E.Coli**'' phat hign d 4/18 m l u nude, vugt QC tir khdng dang kd din 11 ldn.
(Cdc chi tieu ddnh ddu (a) la chi tiiu duge cdng nhgn Vilas; (b) dugc cdng nhgn Vimcerts 112).
3. KET LUAN
3.1. Ket luan ve chat lirgng nirdc 3.1.2. Ddi chidu vdi QCVN 08- MT:2015/BTNMT ddi vdi egt Al - (Sd dung cho myc dich cap nude sinh hogt), chat lugng nude viing nghidn cuu, cd mgt sd chi tieu ed dau hi?u 6 nhilm nh?, gdm: BODs*"', COD*"* (do d nhiem huu co), tdng chat rdn lo ldng, Nitrat (NO3" tinh theo 'HfK Mn '^"^ tong dau, m5*'=^, Coliforms*"'vaE.Coli'"\
3.1.3. Chat lugng nude trong ho chda vd tgi cde nhdnh sudi trong he th6ng su6i Td Vdi dd dieu ki^n sd dyng cho myc dich cdp nude sinh hogt (sau khi dp dung xii ly thdng thudng).
3J2. Ket lu$n ve tru l i r ^ g ddp ung nhu cau cap nirdc sinh ho^t
3.2.1. Vi^c Idy nude td hd chda Td Vdi cho cdng trinh h? thong xu ly nude nhdm cap nude cho sinh hoat Id kha thi.
3.2.2. Tr& lugng nude hd mda khd Id 76.090 m^, dd c^p nude an toan cho nhu eau nude tieu
thy cho sinh boat cua 1000 bg dgi vd 3.500 dan bdn xd Nggc Dudng (thdnh phd Hd Giang) [12]
va du cd eho muc dich thuy lgi. (TrQ lugng nude ho miia khd ldn gap - 1,3 lan lugng nude tidu thy cho sinh boat la 60.000 m''/miaa).
3.2.3. Khd ndng cdp nude cua ho Ta Vdi, vdi lugng nude bh cap miia khd la 300.000 m^, ldn gdp 5 ldn lugng nude tidu thy cho sinh boat la 60.000 m^/mda.
TAI LI?U THAM KHAO 1. Vu Chi Ddn vd Vuang Lg Tidn (2001),
"Nghien cuu hifu qud eua rimg nudi duang ngudn nu&c", Dai hge lam nghi?p Bde Kinh, Trung Qu6e, (Nguyin Tien Nghen djch), Tdi lieu tham khdo cua Bg mdn Ldm Sinh, Trudng DH Lam nghigp.
2. Pham Vdn Didn (2006), "Nghien cicu khd ndng gia nu&c cua mdt sd thdm thue vgt &
viing phdng h^ thuy diin tinh Hda Binh", luan an Tidn sT ndng nghiep, Trudng DH Lam nghigp HdTdy.
3. Chi eye thdng ke tinh Ha (jiang, ndm 2016, Nien gidm thdng ki tinh Hd Giang.
4. Vu Thi Quynh Nga (2009), " Nghien cuu ddc trieng thdm vd giic nu&c tiim tdng ciia ddt rieng tgi Nui Ludt, Xudn Mai, Hd Ngi". Lugn vdn Thgc sT khoa hgc lam nghi5p, Trudng DH Lam nghidp...
Ngu&i phdn bifn: TS. Nguyin Bdng Tuc Phdn bifn xong: 21/9/2017
104 TAPCH(TAlNGUYeNNU(5CS64-2017
