M U

Bo co nh gi tc ng mi trng

u t xy dng cng trnh khai thc ct san lp m Long Ha IV

MC LC

iMC LC

iiiDANH MC HNH

ivDANH MC BNG

1M U

11. XUT X CA D N

22. CN C PHP LUT V K THUT CA VIC THC HIN NH GI TC NG MI TRNG

22.1 Cn c php lut v vn bn k thut

42.2 Cc tiu chun, quy chun

42.3 Cc ngun ti liu, d liu

53. PHNG PHP P DNG TRONG TM

74. T CHC THC HIN TM

8CHNG 1 M T TM TT D N

81.1 TN D N

81.2 CH D N

81.3 V TR A L CA D N

101.4. NI DUNG CH YU CA D N

101.4.1 Mc tiu ca d n

111.4.2 C s quy hoch khu khai thc ct

111.4.3 iu kin giao thng vn ti

111.4.4 Cung cp nguyn nhin liu v cc yu t u vo khc

131.4.5 Ch lm vic, cng sut v tui th m

141.4.6 M va v trnh t khai thc

161.4.7 H thng khai thc

221.4.8 Cc thng s h thng khai thc

1.4.9 Hot ng san lp mt bng23

21.4.10 Tr lng a cht

6281.4.11 Phn l san lp

1.4.12 H thng cng trnh ln bin28

1.4.13 Hiu qu kinh t - x hi ca d n3537CHNG 2 - IU KIN T NHIN, MI TRNG V KINH T - X HI

372.1. IU KIN T NHIN V MI TRNG

372.1.1 iu kin v a l, a cht

392.1.2 iu kin v kh tng thy vn

412.1.3 Hin trng cc thnh phn mi trng t nhin

482.2 IU KIN KINH T - X HI

482.2.1 iu kin kinh t

492.2.2 iu kin v x hi

51CHNG 3 - NH GI CC TC NG MI TRNG

513.1. NH GI TC NG

513.1.1 Ngun gy tc ng c lin quan n cht thi

523.1.2 Ngun gy tc ng khng lin quan n cht thi:

533.1.3 i tng v quy m b tc ng

633.1.4 nh gi cc tc ng

773.2 NHN XT V MC CHI TIT, TIN CY CA CC NH GI

773.2.1 Cc nh gi trong giai on thm d

783.2.2 Cc nh gi trong giai on hot ng d n

80CHNG 4 - BIN PHP GIM THIU TC NG XU, PHNG NGA V NG PH S C MI TRNG

804.1. I VI CC TC NG XU

804.1.1 Bo m chp hnh nghim chnh cc qui nh v bo v mi trng

804.1.2 Gim thiu tc ng do nc thi n mi trng

834.1.3 Khng ch dng nc c lan truyn n khu vc khc

834.1.4 Kim sot s thay i ca y bin, ng b

834.1.5 Cng tc san lp

834.1.6 Kim sot v gim thiu tc ng ca d n n mi trng khng kh

844.1.7 Kim sot nhim do rc thi

854.1.8 Vn giao thng

854.2. I VI S C MI TRNG

854.2.1 Phng chng s c trn du

874.2.2 V ng bm ct

884.2.3 An ton phng chng s c chy n

884.2.4 Chng st

89CHNG 5 - CHNG TRNH QUN L V GIM ST MI TRNG

895.1. CHNG TRNH QUN L MI TRNG

935.2. CHNG TRNH GIM ST MI TRNG

935.2.1. Gim st cht thi

935.2.2. Gim st mi trng xung quanh

5.2.3. Gim st khc94

95CHNG 6 - THAM VN KIN CNG NG

956.1. KIN CA Y BAN NHN DN CP X

966.2. KIN CA Y BAN MT TRN T QUC CP X

96.3. KIN PHN HI PHN HI V CAM KT CA CH D N TRC CC KIN CA Y BAN NHN DN CP X V Y BAN MT TRN T QUC CP X

798KT LUN, KIN NGH V CAM KT

981. KT LUN

982. KIN NGH

983. CAM KT

DANH MC HNH

9Hnh 1.1. V tr khu vc thm d ct san lp Long Ha IV

10Hnh 1.2. Khu vc thm d khai thc ct

15Hnh 1.3. Mt ct ngang tuyn bao (khng t l)

1Hnh 1.4. Tu ht phun Vit M (Ellicott) cng sut 4170 CV, nng sut 1.500m3/gi

618Hnh 1.5. Tu v quy trnh khai thc ct

19Hnh 1.6. S h thng khai thc (Khng t l)

20Hnh 1.7. S cng ngh khai thc (khng t l)

2Hnh 1.8. Phn l san lp

8Hnh 2.1. Bn v tr v phm vi d n, v tr m ct xin khai thc37Hnh 3.1. S thit k ghe khoan theo cng ngh air-lift51

Hnh 3.2. S chn ngang v vung gc vi b ca bn lng70Hnh 3.3. S chuyn ng tng i ca sng do phn x ca h ct pha trc71Hnh 4.1. M hnh b t hoi trn tu khai thc ct82

DANH MC BNG

Bng 1.1. Ta khu vc m Long Ha IV814Bng 1.2. Ta v tr khu vc m va

21Bng 1.3. Tnh ton s lng thit b khai thc

22Bng 1.4. S lng cng nhn vn hnh khai thc ct trn tu

23Bng 1.5. Tng hp cc thng s h thng khai thc

27Bng 1.6. Tng hp tr lng m Long Ha IV

42Bng 2.1. Cht lng mi trng khng kh khu vc d n

42Bng 2.2. Cht lng mi trng nc khu vc d n

44Bng 2.3. Cu trc s loi cc ngnh to khu vc kho st

45Bng 2.4. a dng thc vt phiu sinh khu vc kho st

45Bng 2.5. Ch s u th thc vt phiu sinh khu vc kho st

45Bng 2.6. Cu trc s loi cc nhm ng vt phiu sinh khu vc kho st

46Bng 2.7. a dng ng vt phiu sinh khu vc kho st

47Bng 2.8. Ch s u th ng vt phiu sinh khu vc kho st

47Bng 2.9. Cu trc s loi VKXSCL khu vc kho st

48Bng 2.10. a dng VKXSCL khu vc kho st

48Bng 2.11. Ch s u th VKXSCL khu vc kho st

54Bng 3.1. Tiu ch nh gi quy m tc ng

55Bng 3.2. Quy m tc ng do hot ng trin khai d n

64Bng 3.3. Nng cc cht nhim c bn trong nc thi sinh hot

77Bng 3.4. Mc chi tit v tin cy ca cc nh gi trong giai on thm d, ly mu

78Bng 3.5. Mc chi tit v tin cy ca cc nh gi trong giai on thm d, ly mu

Bng 4.1. Danh mc phng tin k thut v vt t c bn ca b cm ng trn du86

89Bng 5.1. Chng trnh qun l mi trng

91Bng 5.2. Danh mc cc cng trnh mi trng v thi gian thc hin

92Bng 5.3. Kinh ph s dng trong giai on thm d

92Bng 5.4. Kinh ph s dng trong giai on d n i vo hot ng

M U

1. XUT X CA D N Trong nhng nm gn y, cng vi s pht trin chung ca thnh ph, qu trnh th ha vng ven bin Cn Gi ngy mt tng, ko theo nhu cu s dng vt liu san lp phc v cho vic xy dng c s h tng ngy cng tng cao.

D n u t xy dng cng trnh H thng cng trnh ln bin v h tng k thut th thuc d n Khu th du lch bin Cn Gi nhm m rng phn t khng ngp triu ra pha bin lm ni ngh ngi, gii tr v dch v, c tng khi lng san lp theo tnh ton khong 25 triu m3 vt liu san lp. Din tch ton b d n khong 600 ha, din tch thi cng san lp khong 400 ha.

Cng ty C phn th Du lch Cn Gi k hp ng kinh t vi Trung tm Nghin cu Cng ngh v Thit b Cng nghip thuc Trng i hc Bch khoa thnh ph H Ch Minh lp n thm d m ct san lp Long Ha IV, trnh thm nh v ph duyt n c c s tin hnh cng tc thm d v c S Ti nguyn v Mi trng thnh ph H Ch Minh cp giy php thm d s 711/GP-TNMT-QLTN ngy 12/09/2007.

Bo co kt qu thm d m ct san lp Long Ha IV c Hi ng thm nh n, bo co a cht trong hot ng khong sn thnh ph H Ch Minh thm nh theo quy nh ca Lut Khong sn v Lut sa i, b sung mt s iu ca Lut Khong sn, c ph chun trong quyt nh s 735/Q-TNMT-QLTN ngy 01/11/2010. Tr lng ct san lp tnh n 10/03/2008 cp 121 l 2.340.980 m3.

D n u t xy dng cng trnh khai thc l thin m ct san lp Long Ha IV c thnh lp theo hng dn ca B Cng nghip ti thng t s 03/2007/TT-BCN ngy 18/6/2007 Hng dn lp, thm nh v ph duyt D n u t xy dng cng trnh m khong sn rn; Ngh nh s 12/2009/N-CP ngy 12/02/2009 "V qun l d n u t xy dng cng trnh" ca Chnh ph trn c s tr lng ct san lp c ph duyt v cng sut khai thc m 2.340.980 m3/nm.

Bn cnh nhng li ch kinh t - x hi m m ct san lp Long Ha IV mang li th vn c nhng tc ng nh hng n mi trng sinh thi t vic khai thc ct ny. Nhn thc su sc v vn trn cng nh tun th theo cc quy nh hin hnh v bo v mi trng, Ch u t d n l Cng ty C phn th Du lch Cn Gi phi hp vi Vin Nc v Cng ngh Mi trng (n v t vn) tin hnh lp bo co nh gi tc ng mi trng cho d n. Qu trnh nh gi tc ng mi trng cho d n bt u vo khong thng 11/2010 bao gm cc ni dung chnh nh sau: Kho st chi tit khu vc d n;

Thu thp cc ti liu lin quan;

Ly mu phn tch nh gi hin trng cht lng mi trng khu vc d n;

iu tra tham vn kin cng ng v vic trin khai d n;

Lp bo co nh gi tc ng mi trng;

Hon thin h s TM xin thm nh S Ti nguyn v Mi trng.

Mc tiu ca TM l nhn nh v nh gi cc nguy c c th xy ra khi trin khai xy dng cng nh a d n vo khai thc c lin quan n vic ph v cn bng sinh thi t nhin v pht sinh cc cht thi gy nhim mi trng cng nh cc s c v mi trng. Trn c s , trong qu trnh xut v thit lp d n, ch u t c bit ch trng n vic xy dng phng n gim thiu nhm m bo cc hot ng khai thc ca d n khng to ra cc nh hng ln v mt mi trng ng thi cng khng ph v cn bng sinh thi.2. CN C PHP LUT V K THUT CA VIC THC HIN NH GI TC NG MI TRNG

Bo co TM d n u t xy dng cng trnh khai thc ct san lp m Long Ha IV, thuc x Long Ha, huyn Cn Gi, Tp.HCM vi cng sut khai thc 2.340.980 m3/nm c thc hin da trn cc vn bn php l v h s k thut di y:

2.1. Cn c php lut v vn bn k thut

Lut Bo v Mi trng s 52/2005/QH c Quc hi nc Cng ha X hi Ch Ngha Vit Nam thng qua ngy 29 thng 11 nm 2005 v c hiu lc t ngy 01/07/2006; Lut Ti nguyn nc c Quc hi nc Cng ha X hi Ch Ngha Vit Nam thng qua ngy 26 thng 11 nm 2003;

Lut a dng sinh hc s 20/2008/QH12 c Quc hi nc Cng ha X hi Ch Ngha Vit Nam thng qua ngy 13 thng 11 nm 2008;

Lut Phng chy cha chy s 27/2001/QH10 c Quc hi kha X thng qua ngy 29/06/2001;

Ngh nh s 80/2006/N-CP ngy 09 thng 08 nm 2006 ca Chnh ph v vic quy nh chi tit v hng dn thi hnh mt s iu ca Lut Bo v Mi trng;

Ngh nh s 21/2008/N-CP ngy 28/02/2008 v vic sa i, b sung mt s iu ca Ngh nh s 80/2006/N-CP ngy 09 thng 08 nm 2006 ca Chnh ph v vic quy nh chi tit v hng dn thi hnh mt s iu ca Lut Bo v Mi trng;

Quyt nh 23/2006/Q-BTNMT ngy 26/12/2006 v vic ban hnh danh mc cht thi nguy hi;

Ngh nh 59/2007/N-CP ngy 09/04/2007 ca Chnh ph v qun l cht thi rn; Thng t 13/2007/TT-BXD ngy 31/12/2007 ca B Xy dng v vic Hng dn mt s iu ca Ngh nh 59/2007/N-CP ngy 09/04/2007 ca Chnh ph v qun l cht thi rn;

Ngh nh s 68/2005/N-CP ngy 20 thng 05 nm 2005 ca Chnh ph v An ton ha cht;

Thng t 05/2008/TT-BTNMT ngy 08/12/2008 ca B Ti nguyn v Mi trng v vic hng dn v nh gi mi trng chin lc, nh gi tc ng mi trng v cam kt bo v mi trng;

Quyt nh 04/2008/Q-BTNMT ngy 18/07/2008 ca B Ti nguyn v Mi trng ban hnh Quy chun K thut Quc gia v Mi trng;

Thng t 16/2009/TT-BTNMT ngy 07/10/2009 ca B Ti nguyn v Mi trng quy nh Quy chun K thut Quc gia v Mi trng;

Quyt nh s 3733/2002/Q-BYT ngy 10/10/2002 ca B trng B y t v vic ban hnh 21 tiu chun v sinh lao ng, 05 nguyn rc v 07 thng s v sinh lao ng;

Quy phm k thut khai thc m l thin TCVN:5326-2008;

Quy chun k thut Quc gia v an ton trong khai thc m l thin ban hnh km theo thng t s 20/2009/TT-BCT ngy 07/07/2009 ca B Cng thng;

Thng t s 03/2007/TT-BCN ngy 18/06/2007 Hng dn lp, thm nh v ph duyt D n u t xy dng cng trnh m khong sn rn ca B Cng nghip; Quyt nh giy php thm d s 711/GP-TNMT-QLTN ngy 12/09/2007 v ph duyt tr lng khong sn s 735/Q-TNMT-QLTN ngy 01/11/2010 ca S Ti nguyn v Mi trng Tp.HCM vi tr lng cp 121 l 2.340.980 m3.

2.2. Cc tiu chun, quy chun

QCVN 05:2009/BTNMT Quy chun k thut quc gia v cht lng khng kh xung quanh;

QCVN 06:2009/BTNMT Quy chun k thut quc gia v mt s cht c hi trong khng kh xung quanh;

QCVN 08:2008/BTNMT Quy chun k thut quc gia v cht lng nc mt;

QCVN 10 : 2008/BTNMT - Quy chun k thut quc gia v cht lng nc bin ven b.

2.3. Cc ngun ti liu, d liu

Cc ngun ti liu, d liu tham kho

m hc v kim tra ting n, Nguyn Hi, Nh xut bn Gio dc

Bi ging nh gi tc ng mi trng, Vng Quang Vit, 2002;

nh gi tc ng mi trng, Phm Ngc H, Hong Xun C, Nh xut bn i hc Quc gia H Ni, 2000;

nhim khng kh, inh Xun Thng, Nh xut bn i hc quc gia TP. HCM, 2007 (ti bn);

X l nc thi th v cng nghip, Lm Minh Trit, Nguyn Thanh Hng, Nguyn Phc Dn, Nh xut bn i hc quc gia TPHCM, 2004;

nhim khng kh v cc bin php gim thiu, Nguyn Quc Bnh, Bi ging EPC, 1998;

Gio trnh Qun l v x l cht thi rn, Nguyn Vn Phc, Nh xut bn xy dng, 2008.Ngun ti liu, d liu do ch d n to lp

Bo co kt qu kho st Ct san lp khu th du lch bin Cn Gi;

Thuyt minh d n u t Xy dng cng trnh khai thc ct san lp m Long Ha IV, thuc x Long Ha, huyn Cn Gi, Tp.HCM; Thit k c s d n u t Xy dng cng trnh khai thc ct san lp m Long Ha IV, thuc x Long Ha, huyn Cn Gi, Tp.HCM;

S liu thu thp, iu tra hin trng khu vc d n ca n v t vn lp bo co nh gi tc ng mi trng.

3. PHNG PHP P DNG TRONG TM

Cc phng php nh gi tc ng mi trng cho d n u t Xy dng cng trnh khai thc ct san lp m Long Ha IV, thuc x Long Ha, huyn Cn Gi, Tp.HCM bao gm:

Phng php nhn dng

M t h thng mi trng;

Xc nh tt c cc thnh phn/hng mc ca d n nh hng n mi trng;

Nhn dng cc dng thi, cc vn mi trng lin quan phc v cho cng tc nh gi chi tit.

Phng php nh gi nhanh

Nhm c tnh ti lng cc cht nhim sinh ra trong qu trnh khai thc d n theo h s nhim do t chc Y t Th gii thit lp.

Phng php d bo xu th bin i

Trn c s nghin cu kho st cc khu vc khai thc ct trong khu vc c th d bo c tc pht trin, nguy c tc ng tim tng do khai thac ct gy ra i vi mi trng xung quanh cng nh xu th bin i cht lng mi trng do cc tc ng ny, lm c s cho vic xut cc gii php gim thiu tc ng xu v ng ph cc s c mi trng ph hp v hiu qu.Phng php lit k

Nhm lit k cc tc ng n mi trng do hot ng ca Khai thc ct san lp m Long Ha IV, thuc x Long Ha, huyn Cn Gi, Tp.HCM c th gy ra, bao gm cc tc ng t nc thi, kh thi, cht thi rn, an ton lao ng, chy n, v sinh mi trng trong khu vc. y l mt phng php tng i nhanh v n gin, cho php phn tch cc tc ng ca nhiu hot ng khc nhau ln cng mt nhn t.Phng php phng vn, iu tra x hi hc v tham vn kin cng ng

Phng vn cng ng dn c sinh sng ti cc khu vc dn c tp trung ln cn khu d n c s liu nh gi hin trng mi trng xung quanh khu vc d n;

Phng vn vi i din chnh quyn a phng cp x: UBND v UBMTTQ x Long Ha, huyn Cn Gi, Tp.HCM.

Phng php so snh

Da vo kt qu kho st, o c ti hin trng, kt qu phn tch trong phng th nghim, kt qu tnh ton theo l thuyt so snh vi tiu chn/quy chun Vit Nam nhm xc nh cht lng mi trng ti khu vc d n.Phng php kho st thc a

nh v d n, cc im o c, ly mu v cc i tng cho lin quan khc bng h thng nh v ton cu (GPS);

Kho st hin trng khu vc d n;

Kho st khu vc ln cn xung quanh d n;

Phng php ly mu v phn tch phng th nghim

Thu thp v phn tch trong phng th nghim ca Vin Nc v Cng ngh Mi trng cc thng s o c nhm qua nh gi c hin trng cht lng mi trng nn khu vc d n. Phng php chuyn gia

Da trn hiu bit v kinh nghim v khoa hc mi trng ca cc chuyn gia nh gi tc ng mi trng ca Vin Nc v Cng ngh Mi trng (Weti).

4. T CHC THC HIN TM

Ch u t

: CNG TY C PHN TH DU LCH CN GINgi i din: ng Nguyn nh Thi Chc v: Tng Gim c

Tr s chnh

: 44/14 Nguyn Vn u, P.6, Q. Bnh Thnh, Tp.HCM

in thoi

: 08.35155081

Fax: 08.38445911

n v t vn: VIN NC V CNG NGH MI TRNG

Ngi i din: ng Lm Minh Trit Chc v: Vin trnga ch

: C17 C X Lam Sn, ng Nguyn Oanh, P17, Q. G Vp, TP.HCM

in thoi

: 08.39844443 Fax: 08.39844442

Danh sch nhng ngi tham gia thc hin bo co nh gi tc ng mi trng d n u t xy dng cng trnh khai thc ct san lp m Long Ha IV, thuc x Long Ha, huyn Cn Gi, Tp.HCM nh sau:

STTH tnTrnh chuyn mnn v cng tc

1Lm Minh TritGio s Tin sVin Nc v Cng ngh Mi trng

2Nguyn nh ThiTng Gim cCng ty c phn th du lch Cn Gi

3Lm Th Thu OanhK s Mi trngVin Nc v Cng ngh Mi trng

4Phng Ngc Thanh QuyK s Mi trngVin Nc v Cng ngh Mi trng

5Nguyn L HngC nhn Mi trngVin Nc v Cng ngh Mi trng

6Chu Kin QucC nhn sinh thiVin Nc v Cng ngh Mi trng

Vi s tham gia ca nhiu nhm chuyn gia am hiu v nh gi tc ng mi trng: cc chuyn gia v kinh t mi trng, xy dng, sinh thi, v cc chuyn gia mi trng thuc cc lnh vc: cht lng nc, khng kh, khong sn.CHNG 1 M T TM TT D N

1.1. TN D NU T XY DNG CNG TRNH KHAI THC CT SAN LP M LONG HA IV, THUC X LONG HA, HUYN CN GI, TP.HCM, QUY M 2.340.980 M3/NM.1.2. CH D NTn ting Vit: CNG TY C PHN TH DU LCH CN GINgi i din: ng Nguyn nh Thi Chc v: Tng Gim c

Tr s chnh: 44/14 Nguyn Vn u, P.6, Q. Bnh Thnh, Tp.HCM

in thoi: 08.35155081

Fax: 08.38445911

1.3. V TR A L CA D N

Khu vc thm d nm khong gia vnh ng Tranh v Vnh Gnh Ri, ngoi khi x Long Ha, huyn Cn Gi, Tp H Ch Minh, cch trung tm huyn Cn Gi khong 15km v pha ng Nam (xem Bn v tr giao thng)V quy m chim khong 1% din tch bi triu ven bin c su di 2 mt v 0,5% din tch bi triu c su di 6 mt.

Khu vc m c din tch 100 ha v c gii hn bi cc im gc c ta VN2000 mi 6o nh sau:

Bng 1.1. Ta khu vc m Long Ha IVim gcTa WGS 84 VN 2000 (m)Din tch

(ha)

XY

A1146500714250100

B1146500715250

C1145500715250

D1145500714250

Hnh 1.1. V tr khu vc thm d ct san lp Long Ha IV

Hnh 1.2 - Khu vc thm d khai thc ct

1.4. NI DUNG CH YU CA D N D n u t xy dng cng trnh m l thin khai thc ct san lp Long Ha IV, x Long Ha, huyn Cn Gi, TP.HCM khng s dng t, ch s dng mt nc. Trc khi khai thc, Cng ty C phn th Du Lch Cn Gi phi hp vi Cng ty TNHH Mt Thnh vin Bo m An ton Hng Hi Min Nam ra thng bo n cc phng tin thy hot ng trong khu vc bit. V vy, trong bo co TM ch cp n cc vn tc ng nh hng n bin do khai thc ct gy ra v khng cp n vn gii phng mt bng v ti nh c.

1.4.1. Mc tiu ca d nKhai thc ct san lp san lp mt bng d n u t xy dng H thng cng trnh ln bin v h tng k thut th thuc d n Khu th du lch bin Cn Gi.1.4.2. C s quy hoch khu khai thc ct Hp ng kinh t v/v t vn kho st v thc hin n kho st ct san lp khu th du lch ln bin Cn Gi TP.H Ch Minh s 140/2006/H KHCN, ngy 12/04/2006 gia Cng ty C phn th Du lch Cn Gi v Trung tm Nghin cu Cng ngh v Thit b Cng nghip HBK TP.HCM;

n Kho st ct san lp Khu th du lch ln bin Cn Gi 04/2006. Trung tm NCCN&TBCN;

Giy php kho st khong sn s 12/GP UBND ngy 16/06/2006 v/v kho st ct san lp ti khu vc x Long Ha, huyn Cn Gi TP.HCM.

1.4.3. iu kin giao thng vn ti

Ct san lp t bin c bm ht trc tip theo h thng ng ng vo mt bng d n trn b. Khong cch trung bnh t m ti trung tm khu vc san lp khong 3-4km. Trong khu vc thm d, h thng giao thng thy kh pht trin. Cc sng ng Tranh, Ch V, Sng Dinh u l nhng h thng giao thng thy quan trng ni vi cc cng nc su cng nh cng sng ni a nm dc theo sng Th Vi v cc khu cng nghip dc sng Si Gn, Nh B. V vy, vic vn chuyn vt liu xy dng cho khu vc ln bin sau ny c th s dng h thng giao thng thy mt cch thun li.

H thng ng b cha pht trin, ch yu c con ng nha chnh chy t ph Bnh Khnh n Cn Thnh v Long Ho, cn cc ng i qua cc trung tm x khc thng ri v t .

Nhn chung, iu kin giao thng khu vc thm d ch c giao thng thy l pht trin, giao thng b cn hn ch. Tuy nhin do vic khai thc ct ti khu vc thm d a ngay ln san lp ti khu th bin Cn Gi (cch trung tm khu vc thm d khong 3,0 - 4,0 km) nn c im giao thng khng nh hng nhiu n vic tiu th ct san lp ti m. 1.4.4. Cung cp nguyn nhin liu v cc yu t u vo khc

1.4.4.1. Tr lng khong sn

m bo cho m hot ng t cng sut thit k trong thi gian 12 thng, tr lng ct san lp khai thc c c trong din tch m (sau khi tr tn tht khai thc) c thm d, ph duyt cp 121 l 2.340.980 m3.

1.4.4.2. Cung cp nguyn nhin liu

a. Cung cp in

M ct san lp Long Ha IV, thnh ph H Ch Minh khng c cc h tiu th in cng nghip. Thit b khai thc ca m s dng ng c diesel.

Chiu sng mt bng san lp s dng in h p 220v ly t mng in li khu vc qua trm bin p 22/15/0,4Kv do cng ty u t.

b. Cung cp nc

Nc sinh hot trn b c ly t h thng nc my.

Nc n ung, sinh hot cho cng nhn lm vic trn tu ht c ly t trn b, cha trong cc bn trn tu ht.

c. Ngun vt t k thut

Nhin liu cung cp cho cc thit b khai thc trong m do nh thu thi cng chu trch nhim thc hin.

1.4.4.3. Cc yu t u vo khc

a. Ngun nhn lc

Cn b qun l: Ngun cung cp cn b qun l thuc Cng ty C phn th Du lch Cn Gi, iu ng trong ni b Doanh nghip.

b. Cng nhn

Cng nhn vn hnh thit b thi cng, xy dng mt bng san lp do nh thu thi cng chu trch nhim thc hin.

c. C s h tng khu vc m

Bin Cn Gi l tuyn giao thng thy c nng lc vn chuyn ln thuc quyn qun l ca Cng ty TNHH Mt thnh vin Bo m An Ton Hng Hi .

d. Thng tin lin lc

H thng thng tin lin lc vi bn ngoi s dng my b m, radio. Vic thng bo khu vc hot ng khai thc c thc hin thng qua Cng ty TNHH Mt thnh vin Bo m An Ton Hng Hi thng bo n cc phng tin thy hot ng trong khu vc bit. Ni dung chnh gm c:

Phng tin thi cng: Loi tu, kch thc tu.

H hiu.

Thi gian thi cng: 07/24 gi trong ngy. D kin thi gian thi cng: bt u t thng 03/2012.

Cc phng tin hnh thu ra vo khu vc lu gim tc , p dng cc bin php cn thit v lin lc bng VHF vi n v thi cng m bo an ton hng hi.

1.4.5. Ch lm vic, cng sut v tui th m

1.4.5.1. Ch lm vic

S ca lm vic trong ngy: 01 ca/ngy.

S gi lm vic trong ca: 7 gi/ca.

S ca lm vic trong thng: 26 ca/thng.

1.4.5.2. Cng sut khai thc m

Cng sut m thit k: 2.340.980 m3/nm.

1.4.5.3. Tui th m

Thi gian khai thc m tnh bng thi gian xy dng c bn m cng thi gian khai thc t cng sut thit k v thi gian ng ca m, xc nh theo cng thc:

T = T1 + T2 + T3, nm

Trong :

T1 = 01 thng l thi gian xy dng c bn m.

T2 l thi gian khai thc m vi cng sut thit k, c tnh theo cng thc:

thng

Trong : 12 l s thng khai thc trong nm

Khi kt thc khai thc, di tc dng thy lc, b mt y khai trng s t ng c san bng theo gc n nh t nhin ca vt liu san lp. V nh vy, khng c khi lng ng ca m ngoi khai trng. Thi gian ng ca m ch yu lin quan n vic lp h s ng ca m, kt thc hiu lc giy php khai thc v lm cc cng vic lin quan: T3 = 02 thng.

T = 01 + 09 + 02 = 12 thng, ly trn 1 nm.

1.4.6. M va v trnh t khai thc1.4.6.1. M va

Vi loi hnh m vt liu san lp di nc, cng tc m va tng i n gin, v nguyn tc c th tin hnh khai thc ng thi trn ton b khi tr lng vt liu san lp c thm d.

a. V tr m va

Ph hp vi s lng thit b khai thc huy ng, m ct san lp Long Ha IV c m va khai thc ti im gc D.

Bng 1.2. Ta v tr khu vc m vaim gcTa VN2000

X (m)Y (m)

C11455007142500

b. Khi lng m va

* p bao

Ton b khu vc thuc D n u t xy dng cng trnh H thng cng trnh ln bin v h tng k thut th thuc d n Khu th du lch bin Cn Gi c p bao gi ct li trong mt bng san lp.

m bo an ton v mi trng, khng nc chy trn cn thit phi p bao trn ton b din tch san lp. Chiu cao ln hn cao san lp trung bnh khong 01m ngn lng nc bm ht km theo vt liu san lp t bin vo v nh hng dng chy ch li bin. Chiu cao mt thp dn v pha bin.

Theo tin san lp, thn c p theo cc lp chng ln nhau cho n cao thit k.

Vt liu p thng thng s dng l t st.

Vic tm kim ngun t st p tuyn bao trong khu vc xy dng d n gp nhiu kh khn v vy cn thit phi c bin php thi cng tuyn bao thay th vt liu t st m vn m bo kh nng gi li khi lng ct san lp bm ht ln mt bng san lp. Bin php thi cng tuyn bao xut s dng vi a k thut c cng chu lc cao thng s dng trong cc cng trnh xy dng may thnh cc ng kn, ng knh ng khong 03m. Cc on ng c bm ct y vo bn trong t phng ln thnh cc ng ct. Di tc dng ca trng lng ct c trong lng ng s chu c lc y ngang ca vt liu san lp bm t bin. m bo an ton thi cng, trnh cc s c mi trng xy ra khi tuyn ct b b, tin hnh xy dng thm mt tuyn pha bn ngoi cch tuyn chnh khong 150m.

Hnh 1.3. Mt ct ngang tuyn bao (khng t l)

b. Di chuyn thit b thi cng ti khai trng

Thi gian di chuyn tu ht bm ht vt liu san lp ti khai trng ph thuc vo nh thu thi cng. Thit b thi cng phi c mt trc khi kt thc cng tc p bao.

1.4.6.2. Trnh t khai thc

Khai thc cun chiu, ht di khai thc ny n di khai thc khc.

Hng khai thc t bin gii m vo trung tm, t xa vo gn.

1.4.7. H thng khai thc1.4.7.1. c th ca cng vic khai thc vt liu san lp di nc

M vt liu san lp di nc cng l loi hnh m l thin nhng c nhng c th ring bit:

Khai thc trong iu kin khng quan st trc tip c khu vc khai thc.

Khai thc trong iu kin nc chy v cc phng tin giao thng thy cng hot ng trn cng mt khu vc.

1.4.7.2. Cu to v v c ch hot ng ca thit b khai thc

Thit b khai thc la chn cho m ct san lp Long Ha IV l tu ht xn thi. Tu ht xn thi l phng tin chuyn dng cho cng tc no vt sng bin. Gi tr tu ht rt ln, ty thuc cng sut, tnh nng c th ti 80 t ng/chic.

Hnh thc ph hp khai thc m ct Long Ha IV l u thu thi cng i vi cc n v c phng tin no vt chuyn dng. Ph hp vi cng sut m, khong cch bm ht ti a 04km, chiu su mc nc max 4,2m, chiu dy tng st vt liu san lp trung bnh 2,28m, la chn tu ht cng sut 1.500 m3/gi, cng sut 4.170KW.

Hnh 1.4. Tu ht phun Vit M (Ellicott) cng sut 4170 CV, nng sut 1.500m3/gi

a. Cu to

Tu ht xn thi gm c cc b phn: thn tu, bm ht, ng c bm, thit b nh v, li ct lm ti vt liu ht, ti, h thng ng t ni trn phao. C cu lm ti t bng c gii chuyn ng bng ng c in qua hp gim tc v trc chuyn ng. C cu ht v lm ti c gn vi khung tu, nng h c cu ht bng ti.

ng ht gm phn ni trn mt nc v phn chm di mt nc, c khp ni mm iu chnh chiu su khai thc v phng bin dng pht sinh khi lm vic. Phn ng ht c c cu lm ti c gn vo khung nng.

H thng ng ni gm cc on ring bit ni vi nhau bng cc khp mm m bo vic di chuyn tu v ng trn mt c bnh thng. Mi on ng ni u c phao t ng, ng dn khp ni mm, cu thang i li v v gi t cp chu lc.

on ng ni tip gip gia mt nc v b s dng ng dn c khp ni cu gii quyt mc chnh cao gia hai on ng.

b. C ch hot ngC ch hot ng ca tu ht xn thi nh sau: Vt liu san lp v nc bin c ht t u ng ht ln khoang cha qua h thng ng. Hn hp nc + vt liu san lp (t l c iu chnh theo gc tip xc gia u ht v thn khong) c bm chuyn qua h thng ng ng ln bi san lp trn b.

Dng vt liu san lp di tc dng ca trng lc t lng ng xung y trong khu vc c b bao, cho ti khi t c cao trnh tn nn theo thit k, nc bin chy trn qua cc ca thot nc thng nhau c b tr sao cho dng chy dung dch bn ct c ko di nht k t u ng phun cho ti ch thot nc khi mt bng san lp. Thi gian lng ng kh ro t 6 thng n 1 nm mi tin hnh xy dng. H s m cht t nhin cng t c kh cao, ph thuc loi vt liu san lp c th t ti h s k = 0,9. c. Quy trnh khai thc ct

Tu ht xng thi vi cng sut 1.500 m3/gi c a ra v tr khai thc ct. Ti y, thit b ht ct c a xung trc tip theo tuyn ng ng ti ni trn mt bin, c gi c nh bng h thng phao ni n ni cn san lp.

Hnh 1.5. Tu v quy trnh khai thc ct

d. Cng ngh khai thc ct

Cc phng php hin ti c p dng khai thc ct bt ngun t cng tc no vt sng, bin truyn thng nh tu ht t trn x lan t hnh, xng gung, tu cuc gu, tu ht bng, tu xng thi. Khai thc ct ti m ct san lp thuc x Long Ho, huyn Cn Gi, TP.HCM c p dng cng ngh khai thc tin tin (bm ht vi cng sut ln, y ct theo ng ng ni trn bin, a ct khai thc trc tip n ni tiu th).

p dng cng ngh khai thc bng tu ht phun Vit M 4170 CV, nng sut ht 1.500m3/gi, h thng ng ng vn chuyn ct di 4km.

Hnh 1.6. S h thng khai thc (Khng t l)

Ghi chu:

1- Tu ht

2- Thit b ht di 18m

3- Phao neo gii hn lung xc khong cch 100m

4- Cc neo c nh tu.

5- Thit b bm y ct.

6- ng ng vn chuyn ct

A = 100m: Chiu rng khonh khai thc

L = 1000m: Chiu di tuyn khai thc.

Hng vn chuyn ct.e. Neo

S dng 2 cc neo sau thn tu, mi ln cm mt cc neo gi tu ht ti khai trng. S dng hai phao neo gi khong cch lung cho thit b ht.

f. Th phao

Din tch m c cp php khai thc v h thng ng ng vn chuyn ct vo bi tip nhn s c n v thi cng hp ng th phao hng dn lung vi C quan Qun l ng thy. Quy cch v v tr th phao theo lch khai thc ca Cng ty C phn th Du lch Cn Gi.

1. Din tch khai thc xong.

2. Din tch ang khai thc.

3. Phao tiu bo hiu khu vc thi cng

Hnh 1.7. S cng ngh khai thc (khng t l)

H thng khai thc sc nc, theo lp bng, khai thc cun chiu, vn ti trc tip thng qua h thng ng ng khp kn, khng c bi thi.

Thit b khai thc l tu ht xn thi chuyn dng. Phng php neo u tu ht c th s dng neo hoc cc. Di chuyn tu ht bm ht ct bng cch ni ra/cun vo dy neo thng qua h thng ti hoc thay i v tr cc nh v.

g. S lng thit bS lng thit b tnh ton s dng phi hon thnh khi lng san lp theo thi gian yu cu, tnh theo cng thc:

Trong :

P: cng sut gi ca thit b, m3/gi

m = 7: s gi lm vic trong ca, gi/ca

A: khi lng san lp, m3Bng 1.3. Tnh ton s lng thit b khai thcSttThit bS lngCng sut thit b (m3/gi)Thi gian thi cngCng sut bm (m3/ca)Khi lng san lp (m3)

1.Xn thi1.500710.5002.340.980

S ca my thc t128---

S tu ht0,41---

Ly trn1---

2.Xn thi ph tr160074.200

h. Nguyn nhin liu s dng Cc loi nguyn nhin liu c th s dng trong qu trnh khai thc ct:

Du Diezel

Du DO

Xng A90, A92

Nht 40 (2% NL xng A92)

Nht 40 (3% NL du DO).

i. Cng nhn vn hnh khai thc ct trn tu

Bng 1.4. S lng cng nhn vn hnh khai thc ct trn tu

STTTrch nhimS lng (ngi)

1Ch u t06

Gim c iu hnh m01

Gim st ch u t05

2iu khin tu ht xn thi (02 chic)14

Nhn cng cho 1 tu ht

Thuyn trng 01

Thuyn ph01

My trng01

My hai01

in trng01

K thut vin cuc I01

K thut vin cuc II01

3Cng20

1.4.8. Cc thng s h thng khai thc1.4.8.1. Chiu cao tng khai thc/kt thc (Ht)

Chiu cao tng khai thc/kt thc chnh l chiu dy lp ct san lp c thm d tr lng, thay i theo khi tr lng t 1,0 - 4,0m, trung bnh 2,28m.

1.4.8.2. Gc nghing sn tng khai thc (Hk)Do chiu dy thn vt liu san lp ln, gc nghing tng khai thc ca m ly theo gc tip xc gia ming ng ht vi thn khong: 300.

1.4.8.3. Chiu rng lung xc/ht (A)Chiu rng lung xc ph thuc vo kch thc ca thit b thi cng v s cng ngh ht s dng. gim tn tht trong khai thc v thit b hot ng hiu qu, ly chiu rng lung xc/ht bng 70m.

1.4.8.4. Chiu di tuyn khai thc (Lt)Chiu di tuyn khai thc l chiu di ho do tu ht to ra trn mt lung xc. Vi phng php khai thc cun chiu, chiu di tuyn khai thc bng chiu rng khai trng, trung bnh 1.000m.

Bng 1.5. Tng hp cc thng s h thng khai thcSTTThng sK hiun vGi tr

1Chiu cao tng khai thc/kt thc HtmT 1,4 m n 4,5 m, trung bnh 2,3 m

2Gc nghing sn tng khai thc

300

3Chiu rng lung xcAm70

4Chiu di tuyn khai thcLtm1000

1.4.8.5. Theo di su

Trn tu ht c trang b thit b nh v v tinh c kh nng nh v chnh xc v tr thit b neo u v mt ct trn mn hnh thit b th hin su mc nc.

Cao a hnh y bin o v trong bo co kt qu thm d s c cp nht, ng b vi my nh v trn tu theo di su ht.

1.4.9. Hot ng san lp mt bng

1.4.9.1. Phm vi san lp

Phm vi san lp c gii hn bi tuyn bao bo v pha ngoi bin v tuyn , k trong bin ni b. Din tch san lp khong ( 378ha. Ranh gii tnh ton khi lng san lp i vi kt cu bao, bin ni b rt vo 3.0m tnh t bin mp ngoi cng trnh.

1.4.9.2. Gii php thi cng san lp

Trn ton b din tch khu t, cng tc san lp c thc hin theo tng , vi s san lp l 4 theo th t san lp t 1 n 4. Cng tc san lp c tin hnh theo 3 giai on ph hp vi iu kin thi cng v iu kin tnh ton n nh mi p. Hng san lp c thc hin dn t trong b ra pha ngoi bin. Vi mi giai on thi cng san lp m bo ngn ct san lp b tri do tc ng ca sng bin v thu triu bin, phm vi san lp mi (ranh san lp ni b gia cc ) b tr cc b bao san lp bng ng vi a k thut (chng loi ng xem trong ph lc km theo) phn tip gip vi cc tuyn bao bo v v k bao quanh bi tm s dng ngay cc li ng vi a lm b bao tng ng. B tr mt bng cc on b bao san lp nh sau:

san lp s 1 v s 2 c phn cch bng on b bao s 1: L1 = 197m

san lp s 1 v s 3 c phn cch bng on b s 2: L2 =573m

san lp s 2 v s 4 c phn cch bng on b bao s 3: L3=1082m

Tu theo tng giai on thi cng san lp vi mi chiu cao p khc nhau m cc ng vi a k thut s dng lm b bao san lp c kch thc khc nhau: Kch thc cc ng vi a lm b bao cho mi giai on thi cng san lp nh sau:

Giai on 1: cc b bao san lp s dng cc ng vi a loi 1 (GT-01) c chu vi ng =11.5m.

Giai on 2: cc b bao san lp s dng cc ng vi a loi 2 (GT-02) c chu vi ng =9.0m.

Giai on 3: cc b bao san lp s dng cc ng vi a loi 3 (GT-03) c chu vi ng =8.0m.

Chiu di mi on ng s dng lm b bao san lp l 30m, dc theo chiu di mi ng b tr 03 cc ng nh bm ct. Chi tit vt liu vi a k thut s dng may ng xem trong phn ph lc km theo.

Ngoi cc b bao phc v san lp cng trnh; dc theo chiu di tuyn bao bo v 2 pha rch L v rch H Thanh (tng ng vi tuyn K1-K2-K3 v K8-K9-K10) b tr cc b bao tm thi, ngn bn ct san lp trn vo cc khu vc nui trng thu sn nm tip gip vi khu t xy dng trong qu trnh thi cng san lp giai on 1. B bao tm ph v thi cng s dng cc ng vi a k thut (ng loi 4) cha ct c kch thc ng H/W=1.0/2.2m. Phm vi b tr ng loi 4 trn mt bng nh sau:

Tuyn K1-K2-K3 c ngn cch vi khu vc pha ngoi bng on b bao s 4 c chiu di L4 = 1444m, b tr cch bin san lp giai on 1 dc theo mt khong l1.4 = 150m v cch v tr im K1 trn mt bng mt khong l2.4=500m. Tuyn K8-K9-K10 c ngn cch vi khu vc pha ngoi bng on b bao s 5 c chiu di L5 = 1355m, b tr cch im K9 dc theo mt khong l1.5 = 500m v cch v tr im K1 theo phng ngang trn mt bng mt khong l2.5=150m.1.4.9.3. Khi lng san lp

Cao thit k theo cao quy hoch iu chnh +2.50 mHn Du. Tnh ton khi lng san lp theo phng php lp li vung 20x20m trn ton b khu vc.

Giai on 1: Khi lng tnh ton vi chiu cao san lp Hsl=3.0m. Theo tng khu san lp phm vi san lp c bo v bng cc ng ct li bao v b bao san lp (pha khng c ) bng ng vi a k thut loi 1 GT- 01.

Din tch san nn:

3,610,491.00 m2

Khi lng t p:

5,467,515.00 m3

Khi lng b ln(d kin):1,408,091.49 m3

Giai on 2: Khi lng tnh ton vi chiu cao san lp Hsl=2m(tnh t cao p nn giai on 1). Phm vi san lp c bo v bng b bao san lp s dng ng vi a k thut loi 2 GT- 02.

Din tch san nn:

3,833,742.00 m2.

Khi lng t p:

7,533,934.00 m3.

Khi lng b ln(d kin):1,786,523.77 m3

Giai on 3: ( Giai on san nn hon thin ): khi lng tnh ton t cao p nn giai on 2 n cao thit k. Khi lng san lp 3,832143 m3. Phm vi san lp c bo v bng b bao san lp s dng ng vi a k thut loi 3 GT- 03, vi chiu cao san lp tnh t cao nn p giai on 2.

1.4.9.4. Quan trc ln thi cng

Nhm nh gi c mc ln cho tng giai on thi cng ng thi lm cn c kim tra cng tc thi cng theo cc chiu cao p n nh cng trnh: trn ton b mt bng thi cng san lp b tr li mc quan trc ln(li 160x160m). Mc quan trc ln kt cu dng cc thp (20AII chiu cao thay i theo chiu cao p. Cc thp c lng bn trong ng nha PVC D100mm bo v. Cc thp c c nh vo tm BTCT M200 1x2 kch thc axb=80x80cm dy 15cm.

1.4.9.5. Ngun vt liu san lp, cc yu cu k thut

Ngun vt liu d kin l ngun ct khai thc ngoi bin Cn Gi (da theo bo co kho st a cht trm tch v a cht cng trnh do cng ty KSTKTV Si Gn thc hin nm 2001 v Bo co kt qu kho st ct san lp khu th du lch ln bin Cn Gi do Trung tm NCCN v Thit b cng nghip thuc i hc Quc gia Tp. H Ch Minh thc hin nm 2006).

cht yu cu sau khi san nn: Xt c im cng trnh xy dng bn trn khu t s c thit k nn mng ring, chn cht nn sau san lp l K=0.85-0.9.1.4.10. Tr lng a cht1.4.10.1. Ch tiu tnh tr lngTheo yu cu ca ch u t, vic khoanh ni cc khi tr lng phi m bo cc yu cu sau:

Hm lng ht bt, st (ng knh ht < 0,05 mm) 1m.

su tnh tr lng tnh t mt y bin : ( 5,0 m.

1.4.10.2. Phng php tnh tr lng

S dng phng php khi a cht tnh tr lng v dng phng php phn mm Surfer kim tra.

Q = S . mtbTrong :

Q: Tr lng ct (m3)

S

: Din tch thn khong tnh tr lng (m2), c xc nh trn bn bng phn mm MapInfor 8.0

mtb : Chiu dy trung bnh thn ct (m) c tnh bng trung bnh cng b dy ct tham gia tnh tr lng ca cc l khoan trong khi tr lng.

a. Tr lng khai thc

Bng 1.6. Tng hp tr lng m Long Ha IVCp tr lngKhi tr lngDin tch (m2)B dy ct (m)Tr lng (m3)

121I-1211.000.0002,340982.340.980

Tr lng khai thc c tnh theo cng thc sau:

Qkt = Qc .(1 - Kkt), m3.

Trong :

Qc l tr lng a cht, m3.

Qkt l tr lng khai thc, m3.

Kkt = 5% l tn tht khai thc c th khai thc di nc khng nhn trc tip c khong sn.

Kt qu tnh ton: Qkt (m Long Ho IV) = 2.340.980 m3Cng tc kho st ct san lp phc v cho d n ny ti hai bi S1 v S2 (tng din tch ct c b dy cng nghip l 24,10 km2) cho kt qu nh sau: tr lng ct san lp cp 333 l 57,76 triu m3, tc l hn gp i tr lng d kin s dng trong d n.b. Qu trnh hon nguyn, phc hi h sinh thi di ncM ct Long Ha IV l m chm di mc nc bin trung bnh v u nm trn bi bi cao ti b bin Long Ha, huyn Cn Gi. su khai thc ct ti a khng qu 4 m. Su hn 4m ch c mt im ti h khoan CG450 (h=6.0m). B dy trung bnh lp ct khai thc ti Long Ha IV l 2.5m. Sau khi khai thc ht ct san lp ti m Long Ha IV, qu trnh bi lng t nhin s san phng dn h khai thc v h sinh thi, ng thc vt trc kia cng dn c hnh thnh tr li. Do , qu trnh hon nguyn xy ra t nhin nn chi ph thc hin cho cng tc hon nguyn mi trng sau khi khai thc m ct Long Ha IV l khng t ra.

Bn cnh , sau khi khai thc ht ct san lp ti m, cc h sinh thi, ng thc vt di nc trc kia cng dn c hnh thnh tr li theo t nhin. Thi gian phc hi nh hin trng trc khi d n tin hnh hot ng ph thuc vo cc iu kin t nhin di nc, a hnh a mo y bin

1.4.11. Phn l san lp

Mt bng san lp D n u t xy dng cng trnh H thng cng trnh ln bin v h tng k thut th thuc d n Khu th du lch bin Cn Gi c chia thnh 04 l san lp (xem s tng mt bng).

Trnh t san lp t cc l pha b ra bin.

Ph hp vi thit b thi cng s san lp tng 2 l mt, mi l c ca x nc

ning nhanh chng thot nc tho kh mt bng.

Hnh 1.8. Phn l san lp

1.4.12. H thng cng trnh ln bin

1.4.12.1. Phng n kt cu ln bin

loi 1: Ti v tr c cao trnh t nhin t -3.5 n -2.0 (h hn du), tng chiu di L=3.287m, cao trnh nh +3.5m (h hn du). Kt cu mi nghing c mi dc phc hp v c thm gim sng, h s mi dc m=2.

Thn c cu to gm:

Tng ht sng BTCT M300 1x2 cao H= 1.0 m

2 lp tetrapod trng lng 3T/1 khi dy 2.3m.

Lp lt vin c trng lng W=200-400 kg/vin cao 1.5m.

Chn khay bo v mi s dng c trng lng 1T/vin, cao h=1.5m.

Lp vi a k thut phn cch gia kt cu v t nn.

Li gm:

Gia lp lt v ng vi a b tr lp m W=10-200kg.

Li bng ng vi a k thut dung tch cha ln nht ca mi ng l 10m3/md. Chiu di ng thit k ln nht L=50m, bm chn ct bn trong

Nn mng : S dng nn t t nhin

loi 2: Ti v tr c cao trnh t nhin t -2.0m n -0.6m (h hn du); tng chiu di L= 1623 m, cao trnh nh + 3.5m (h hn du). mi nghing c mi dc phc hp v c thm gim sng.

Thn t trn xung bao gm cc lp sau:

Tng ht sng : kch thc v kt cu tng t nh tng ht sng ca tuyn loi 1.

Lp ph ngoi : vin khi ln trng lng 1Tn/vin chiu dy xp lp h=1.0m, mi dc m=2.

Lp lt: dng vin khi ln trng lng W=200-400 kg/vin, chiu dy h=1.5m, mi taluy xp m=2.

Lp xp chn khay bo v mi s dng vin khi ln trng lng 1T/vin.

Lp vi a k thut phn cch gia kt cu v t nn.

Li bao gm:

Lp ph bo v ng vi a k thut trng lng W=10-200 kg.

Li bng ng vi a k thut.

Nn mng : S dng nn t t nhin

loi 3: Ti v tr c cao trnh t nhin >-0.6m; tng chiu di L= 635 m, cao trnh nh + 2.5m.

Thn t trn xung bao gm cc lp sau :

Tng ht sng gm 2 loi (loi1:kt cu btng M300 1x2 chn 40% hc ti ch, tng khng thit k phn ht sng; loi 2: Kt cu b tng M300 1x2 ti ch, tng khng thit k phn ht sng).

Lp ph ngoi : vin khi ln trng lng 1Tn/vin chiu dy xp lp h=1.0m, mi dc m=2.

Lp lt s dng vin dng khi ln vi cc vin c khi lng t 200-400 kg/vin, chiu dy h=1m, mi taluy xp m=2.

Lp xp chn khay bo v mi s dng vin khi ln trng lng 1Tn/vin, xp vi chiu dy h=1m.

Lp vi a k thut phn cch gia kt cu v t nn.

Li gm hai loi:

Loi 1: Li bng ng vi a k thut bn trn ph lp bo v trng lng 10-200 kg/vin.

Loi 2: Li bng x b trng lng 10-200 kg/vin, lp ph ngoi mi s dng vin khi ln trng lng t 200-400 kg/vin.

Nn mng : S dng nn t t nhin

loi 4: Ti v tr nm pha trong khu bin ni b c che chn sng mt phn bi tuyn ngm ph sng, tng chiu di tuyn loi 4 l0 L=600m, cao trnh mt t t nhin t -3.0 n -2.0 h hn du). Kt cu thn dng mi nghing c mi dc phc hp v c thm gim sng.

Thn gm:

Tm b tng nh (cao trnh +2.5 kt cu tng t nh tm btng nh b tr trn tuyn chn sng)

Lp ph mi : Tm b tng ct thp (100x100x25 cm) M300 1x2 c sn lp ghp, mi dc xp lp btng ph mi m=2.

Lp lt x b 10-200 kg/vin.

Chn khay bo v mi s dng c trng lng 1Tn/vin, chiu dy h=1.5m.

Lp vi a k thut phn cch gia kt cu v t nn.

Li : Kt cu tng t nh kt cu loi 1.

Nn mng : S dng nn t t nhin.1.4.12.2. chn sng bo v cng (on K5-K6-K7)

V chc nng, chn sng c tc dng che chn sng bo v s yn tnh cho khu nc bn trong bn du thuyn, m bo cho vic neo cp tu thuyn. Vi chiu di tuyn 766m c cu to nh sau:

B rng nh :

B=10 m.

Chiu di tuyn :

L=766 m.

Cao trnh nh (nh tng ht sng):+3.5m (h hn du).

B rng mi :

B1 = 5 m.

dc mi :

m= 2

B rng chn khay mi ngoi:

B2=14.6 m.

B rng chn khay mi trong:

B3=10.0 m.

Thn : Dng mi nghing c mi dc phc hp v c thm gim sng, t trn xung bao gm cc lp:

Tng ht sng (b tr ti mi pha ngoi), kch thc v kt cu tng t nh tng ht sng tuyn loi 1.

Tm BTCT nh : B tr ti mi pha trong, kt cu bng BTCT M300 1x2 ch L rng B=3 m, dy h=0.5m.

Lp ph mt mi ngoi: Pha bin s dng cc khi Tetrapod loi 3T/vin xp hai lp dy 2.3m, b rng khi xp trc tng chn sng l 2 m, v b rng thm gim sng l 5 m.

Lp ph mt mi trong: S dng khi BTCT c sn c kt cu tng t chn xp lp dng bc thang. Pha di tm BTCT l lp lt 4-20 cm dy 40 cm chn 22% dm.

Lp lt: S dng vin dng khi ln trng lng 200-400 kg/vin, chiu dy h=1.5m, mi taluy xp m=2.

Lp xp chn khay bo v mi s dng vin dng khi ln trng lng 1T/vin, chiu dy lp h=1.5m.

Lp vi a k thut phn cch gia kt cu v t nn.

Li : Lm bng ng vi a k thut, lp ph ngoi s dng x b trng lng t 10-200 kg/vin.

Nn mng : S dng nn t t nhin.

ng trn : S dng cc tm BTCT lp gp kch thc mi tm = 100x100x25 cm t trn lp m loi 4-20cm/vin kt hp chn 22% dm lu ln cht.

1.4.12.3. Kt cu bn du thuynBn du thuyn v bi u xe: Gm tuyn chn sng, k bo v b, bao quanh khu vc neo u du thuyn, ng bi trn bn du thuyn, bo hiu cng trnh.

chn sng di 133m kt cu tng t nh tuyn chn sng loi 1.

K bo v b di 1872 m, kt cu bao tng t nh kt cu loi 4.

bao quanh khu vc neo u du thuyn:

Cao trnh nh +2.5 (h hn du).

dc mi m=2.

B rng chn khay mi B=8m

Thn : Kt cu t trn xung bao gm:

Tm b tng ct thp nh M300 1x2 cu to dng ch l, rng B=3.0m, dy h=0.5m.

Lp ph mi s dng tm BTCT t chn xp lp dng bc thang, pha di l lp cp phi dy 40 cm kch thc t 4-20 cm chn 22% dm.

Chn khay bo v mi s dng vin khi ln c trng lng

1Tn /vin.

Li : S dng ng vi a k thut bm chn ct vo bn trong.

Nn mng : Nn t t nhin, mt phn cch gia kt cu vi nn t t nhin c ri lp vi a k thut.

ng bi trn bn du thuyn gm: khu vc bn du thuyn c tng din tch trn mt bng l S=88399 m2 c san lp n cao trnh +2.44 (h hn du) cht K=0.95. mt ng bi c lt ton b bng gch b tng xi mng dy 6 cm.

Bn neo cp du thuyn : Bn dng bn nh, khong cch gia cc tr neo cp L=50m. tng s b tr 04 v tr bn neo cp.

Cc thng s c bn ca bn neo cp du thuyn:

Cao trnh nh bn:

+2.5 ( Hn du).

Cao trnh y bn:

-5.80m (Hn du).

B rng tr :

B =6.40 m.

Chiu di tr :

L = 30.25m.

B rng tr cu cng tc:

Bct = 2.0m.

Chiu di cu cng tc:

Lct = 16m.

Chiu di ponton:

Lp = 10.0m

Chiu rng ponton:

Bp = 6.0 m

Bn neo cp tu thuyn kt cu tr BTCT kt hp cu cng tc di ng (ln xung theo mc nc thy triu) ni vi ponton neo cp tu (phao ni). Gip cho tu thuyn neo cp d dng trong iu kin mc nc thu triu.

1.4.12.4. ngm ph sng

Cao trnh :

+ 0.00m (h hn du).

B rng :

50 m.

H s mi dc:

m = 2

Kt cu bo v mi :

Pha bin chu sng (gm cc lp)

Tetrapod (3T) xp 2 lp.

Lp lt bo v 200-400 kg/vin, dy h=0.6 m.

Lp m c kch thc vin d= 15-35 cm, dy 35 cm..

Lp ph mt ng ct bng nh c cp phi 5-10 cm.

Pha bin ni b

Lp ngoi cng trng lng W=100-300 kg/vin, dy h = 1m.

Lp m kch thc t 10-25 cm, dy 50 cm.

Lp ph mt ng ct bng nh c cp phi 5-10 cm.

ng ct chu vi 12 m gm hai tuyn ng xp chng ln nhau chiu di mi ng 30m.

Chn khay mi

Pha bin (pha chu sng): Chn khay kch thc rng B=10m, c trng lng 0.5-1 Tn/vin. Bn di lt lp vi a k thut chng ln trt.

Pha bin ni b: Kt cu chn khay c dng hc , b rng chn khay B=8m.

Kt cu nh

Tm b tng 2x2x0.3m.

cp phi 5-10 cm, dy 20 cm.

Vi a k thut.

Cng trnh tm: gm cc ponton bng nha composite kch thc (10x6x2 m) c tc dng ngn cn s chuyn ng ca bn ct vo bn trong bin ni b.

1.4.12.5. K tip gip bi tm

Xt v chc nng s dng th k ln bin pha bi tm c tc dng ngn cch phn t san lp bn trong v ct bi tm.

S dng cc ng vi a k thut (Geotube) xp chng ln nhau, cu to k nh sau:

Cao trnh nh k +2.0 (h hn du).

Mi dc thn k m=2.

Kt cu thn k cu to t vi a k thut cng cao.

Cc ng ct thi cng ti cc cao trnh khc nhau xp chng ln nhau.

Pha trn nh k l lp t trng c che ph vi trnh tip xc vi nh nng mt tri.

1.4.12.6. K ln bin ni b tng ng

Kch thc v cc thng s c bn ca :

Cao trnh nh +2.5 (H hn du)

B rng nh 3.5 m.

H s mi dc m=2

Kt cu mi t ngoi vo trong gm :

Tm b tng ct thp t chn (1.2x1.2x0.3 m).

dm 2-5 cm, dy 20 cm.

cp phi 10-20 cm, dy 40 cm.

dm 5-10 cm ph mt ng ct.

Kt cu nh : nh c cu to l cc khi b tng dng ch L ( ti ch hoc lp ghp). Bn di l lp m c cu to t trn xung di nh sau:

B tng 4x6, M100, dy 20 cm.

cp phi 10-20 cm, dy 40 cm.

Ct san lp v tip xc vi ng ct

Lp vi a k thut.

Kt cu chn khay: Chn khay dng hnh thang cn; cao trnh chn khay +1.5m (khu nc nng) v +1m (khu nc su).

lm chn khay c trng lng W=100-300 kg.

B rng chn khay B=3m.

Mi dc chn khay m=2

1.4.13. Hiu qu kinh t - x hi ca d n

Khi D n u t xy dng cng trnh m l thin khai thc m ct san lp Long Ha IV i vo vn hnh s y nhanh tin thc hin d n u t xy dng cng trnh H thng cng trnh ln bin v h tng k thut th thuc d n Khu th du lch bin Cn Gi ca Cng ty C phn th Du lch Cn Gi gp phn pht trin kinh t x hi khu vc.

To cng n vic lm cho ngi lao ng v gim chi ph san lp mt bng.

Pht trin cc dch v i km.

ng gp cho ngn sch nh nc thng qua vic thc hin ngha v thu gm thu gi tr gia tng, thu thu nhp doanh nghip, thu ti nguyn v cc khon ph khc.

CHNG 2 IU KIN T NHIN, MI TRNG V KINH T - X HI

2.1. IU KIN T NHIN V MI TRNG 2.1.1. iu kin v a l, a cht2.1.1.1. c im a hnh

Khu vc khai thc ct nm ngoi bin, gia Vnh ng Tranh v Vnh Gnh Ri. Ton b khu vc khai thc ct u ngp di mc nc bin vi su trung bnh t 1,5 2m, thoi dn v pha Nam, thuc dng a hnh bi t ca sng, ven bin. Mt a hnh y bin trn khu vc S1, S2 tng i bng phng. Gc dc trung bnh khong 0,2 . Trc a hnh chnh ca y bin trong khu vc kho st, thm d l TB-N v B-TN.

Phn trn b l a hnh tch t ven bin, dng m ly v cc thm bin c cu to bi st, bt ct ln bn v mn thc vt vi cao trung bnh t 1 - 2m. Dng a hnh ny b phn ct bi cc h thng knh rch. Thm thc vt ni y ch yu l rng ngp mn vi cc h thc vt nh: c, bn.

Hnh 2.1. Bn v tr v phm vi d n, ranh gii ta v v tr m ct xin khai thc

2.1.1.2. c im v a cht, a mo

a. c im a tngKhu vc kho st phn b rng ri cc trm tch b ri tui Holocen, trt t a tng t di ln nh sau:

H t - Thng Holocen

Ph thng trung - thng H tng Cn Gi (Q22-3cg): Trm tch h tng ny dng di, dng cn thp thoi phn b ko di dc theo trc ng chnh, thng l ni tp trung dn c sinh sng ca ph th Cn Gi. Thnh phn gm ct bt ht nh n mn ln bt st mu xm en, xm nht. b dy 5 10m.Ph thng thng - Trm tch sng (aQ23): Phn b rng ri vng ca sng ng Dnh n b tri sng Tranh. Thnh phn gm bt st ln ct mn v mn thc vt mu xm, xm nht. b dy 5 7m. Ph thng thng - Trm tch sng bin (amQ23): Trm tch ny thng c dng di rng vi trm n trn 1000m m ly ven ra ng bng khu vc ca sng v ven bin trong i thy triu ln xung. Thnh phn gm ct mn ln bt st, bn v mn thc vt, mu xm, xm nht n xm en. B dy khong 7 10m. Ph thng thng - Trm tch bin (mQ23): Thnh to ny phn b trn bi ngm ven bin, hon ton b ngp nc bin. Mt ct gm 3 phn: Phn trn l ct thy triu, y l i tng kho st. B dy tng ct thy triu t 1,0 4,0m , trung bnh 2 3m. Nhn chung b dy ct gim dn t trong b ra ngoi khi.

Phn di l bn, bn xen ct thy triu chuyn xung l st bin mu xm xanh.

Di cng su 19 20m gp tng st loang l ln cui si.

Vt liu trm tch c cung cp mt phn bi h thng sng ng Nai v mt phn c th t dng chy ven bin theo hng t ng Bc xung Ty Nam.

b. c im a mo

Khu vc kho st l di trm tch nm gia mc thy triu cao v triu thp. Bi ngm ko di t ng b hin ti n ng ng su 20m vi chiu rng 25km. Phn bi trn l phn ni ln khi triu rt khng ch bi ng ng mc su 3m, phn ny chu tc ng ch yu ca sng, gi t bin ng v bng phng; phn thn ngm ca bi phn b su t 4 20m.

c. Cc c trng xi l, bi lng v bin dng vch b

S dch chuyn theo phng thng ng: S dch chuyn ca y lung dc sng ng Tranh, sng Ch V v sng Dinh theo phng thng ng xy ra khng ln.

S dch chuyn theo phng nm ngang: do sng v dng chy ven b tng i ln do s di chuyn ca cc cn ct di ng theo ma. Tuy nhin, quy m dch chuyn ngang vi trm m/nm so vi kch thc hng chc km ca bi triu c th coi l nhng bin dng nh.

Cc h s sa bi v d phng sa bi vi chu k no vt: ti khu vc ca sng ng Tranh, sng Dinh v sng Ch V l khu vc xy ra bi lp hoc di chuyn di tc dng ca cc cn ct di ng theo ma. su t nhin 6m nu no vt su 1 m th sau 1 nm s bi lp tr li l 0,58m; nu no su 2m th sau 1 nm s bi lp tr li l 1,16m. Bi thy triu ti khu vc thm d l mt bi bi ln thuc ca sng ng Tranh, c cng quy lut bi lp nh trn.

2.1.2. iu kin v kh tng thy vn

2.1.2.1. iu kin v kh tng

Cn Gi c kh hu nhit i gi ma cn xch o vi hai ma r rt: Ma ma t thng 5 n thng 10.

Ma kh t thng 11 n thng 4 nm sau.

a. Lng ma

m Cn Gi rt cao nhng lng ma li thp nht so vi cc khu vc khc trong thnh ph H Ch Minh, trung bnh hng nm t 1.300 mm 1.400 mm. Lng ma phn b khng u t phi Nam ln phi Bc v t phi ng sang phi Ty.

b. Nhit

Bin nhit trong ngy t 50C 70C, trong cc thng thng nh hn 40C. Nhit trung bnh thng cao nht thng xy ra t thng 3 5 (30 31oC)v thp nht trong khong thng 12 n thng 1 nm sau(24 25OC).

Nhit trung bnh nm l 25,80C. Nhit c hi gim dn t pha Bc xung pha Nam nhng khng ng k.c. Bc x

Lng bc x trung bnh gia cc ngy khng chnh nhau nhiu, lun lun t trn 300 calo/cm2/ngy. Lng bc x bnh qun cao nht vo thng 3 vi 14.2 Kcal/cm2/thng, thp nht vo thng 11 vi 10,2 Kcal/cm2/thng. Lng bc x thng gim dn trong khong thi gian t thng 9 n thng 12. Lng bc x c th bin ng t 14 Kcal/cm2/thng xung 10 Kal/cm2/thng.d. Gi

Chu nh hng ca ch gi ma. Tc gi v hng gi thay i theo ma.

Thi k gi ma ng Bc v ng Nam (gi chng) khng ch l ma kh (t thng 11 ti thng 4 nm sau), vn tc gi trung bnh 2,4m/s.

Thi k gi ma Ty Nam bt u t thng 5 ti thng 10, vn tc gi trung bnh 3,6m/s.

Tuy nhin, khi vo su trong t lin th hng gi c thay i do nh hng ca a hnh. Ni chung, vn tc gi thay i theo cc thng trong nm. Vn tc gi trung bnh c nm 3m/s, cc i l 30m/s.

vng ven bin thng gp gi a phng (gi t, gi Bin). Cc loi gi ny ni chung c cng khng mnh nhng ng vai tr quan trng l lm cho kh hu dc vng ven bin mt m, n ha, thun li cho vic ngh ngi, du lch.

2.1.2.2. iu kin thy vnH thng giao thng thy kh pht trin. Cc sng ng Tranh, Ch V, Sng Dinh u l nhng h thng giao thng thy quan trng ni cc cng nc su cng nh cng sng ni a nm dc theo sng Th Vi v cc KCN dc sng Si Gn, Nh B. V vy, vic vn chuyn vt liu xy dng cho khu vc ln bin bng h thng giao thng thy ny s rt thun li.

Khu vc khai thc thuc ch bn nht triu vi chnh lch gia 2 nh triu khong 0,2 2,5 m. Cc ngy 1 v 15 m lch l thi im triu cng; cn cc ngy 7 v 23 m lch l thi im triu km. Bin triu trung bnh trong nm nc ln t 403 cm. Thi gian triu ln n nh l 6h. triu rt n chn l 6h 45 pht.

Mc nc cao nht l +154 cm, thp nht l -335 cm v mc nc bnh qun nhiu nm l -26cm.

Vn tc dng chy trn bi tnh trung bnh l 0,6 m/s

Chiu cao sng ln nht o c l 2,1m. Chiu cao sng trung bnh l 0,7m vi chu k 4s. Sng ln thng xut hin vo bui chiu ( theo quy lut gi ni).

Ch dng chy khu vc d n

D n khai thc ct m Long Ha III thuc bi S1 v D n khai thc ct m Long Ha IV thuc bi S2 nm cch nhau khong 3,3 km. Do , ch dng chy chung ca khu vc thc hin d n nh sau:

B bin Cn Gi chu nh hng ca dng chy cc sng Lng Tu, Soi Rp, Ci Mp, Dinh v nhng dng chy bin: Dng triu, dng ven do sng, dng do gi, ....

Dng chy trong khu vc vnh Ghnh Ri mang quy lut bn nht triu khng u, trong mt ngy m c 4 ln i hng dng. Dng triu chim khong 90% ln dng tng cng, cn dng d khong 10%.

Do c im ng b v a hnh bin vng nc trc ca sng Cu Long v ng Nai, dng triu ln c hng t ng Bc xung Ty Nam v ngc li khi triu xung. Cng nh mc nc dng triu thng mang tnh cht bn nht triu khng u, thay i theo chu k ngy m.

Dng chy chnh chuyn ng theo hng cc lu vc sng ln: Soi Rp, Lng Tu. Hin tng chy qua bi ch l s trn triu vo cc thi k triu mnh. Tc dng chy ln nht o c trn sng Lng Tu khong 1.5 m/s, trn sng Soi Rp khong 1.3 m/s.

Vn tc dng chy ven b khi cha c cng trnh:

Dng chy ven b ln nht :Vmax = 0.44 m/s

Dng chy ven b trung bnh :Vvcp = 0.28 m/s

Theo bo co nh gi tc ng mi trng, sau khi hon thnh cng trnh ln bin, vn tc dng chy tng cng dc b k v chn sng d bo khong 3m/s.2.1.3. Hin trng cc thnh phn mi trng t nhin

Nhm nh gi hin trng cht lng mi trng nn khu vc trin khai d n, n v t vn thc hin bo co nh gi tc ng mi trng kt hp vi Ch u t tin hnh o c, ly mu v phn tch cht lng mi trng khng kh xung quanh, nc mt v thy sinh vt ti khu vc d n vo ngy 24/11/2010.

2.1.3.1. Hin trng cht lng mi trng khng kh

Bng 2.1. Cht lng mi trng khng kh khu vc d nTTV tr ly muNO2

(mg/m3)CO

(mg/m3)SO2(mg/m3)Bi

(mg/m3)T0 (0C)Tc

gi

(m/s) n

(dBA)

1KK10,0811,0KPH0,0932,32,2 2,856,3 62,0

2KK20,1215,70,130,1033,51,5 357,0 66,8

3KK30,0912,3KPH0,1232,92,7 3,858,9 64,5

QCVN 05:2009/BTNMT0,2300,350,3---

(Ngun: Vin Nc & CNMT WETI, 11/2010)

Ghi ch:

KPH: khng pht hin

KK1: Trong khu vc d n X: 1146500; Y: 0714250; KK2: Trong khu vc d n X: 1146500; Y: 0715250;

KK3: Trong khu vc d n X: 1145500; Y: 0714250.

Nhn xt: Qua kt qu phn tch cho thy, tt c cc ch tiu phn tch u t quy chun cho php (QCVN 05:2009/BTNMT).

2.1.3.2. Hin trng cht lng mi trng nc khu vc d nKt qu phn tch mu nc ca ti PTN cht lng mi trng ca Vin Nc v Cng ngh Mi trng cho kt qu nh sau:

Bng 2.2. Cht lng mi trng nc khu vc d nCh tiun vK hiu muQCVN 10:2008/BTNMT

N1N2N3

pH-7,837,907,946,5 8,5

TSSmg/l1131134650

DOmg/l4,604,805,00 5

T00C26,226,327,530

CODmg/l1515163

Femg/l0,160,200,190,1

Mnmg/l0,020,030,010,1

Znmg/l0,010,020,010,5

Pbmg/lKPH0,01KPH0,05

Cdmg/lKPHKPHKPH0,005

Hgmg/lKPHKPHKPH0,001

Crmg/lKPHKPHKPH0,1

Du khongmg/lKPHKPHKPHKPH

ColiformMPN/100ml4,6 x 1035,1 x 1036,4 x 1031000

(Ngun: Vin Nc & CNMT WETI, 11/2010)

Ghi ch: QCVN 10:2008/BTNMT: Quy chun k thut quc gia v cht lng nc bin ven b - vng nui trng thy sn, bo tn thy sinh. Thng s in m: cao hn hoc thp hn quy chun cho php.

KPH: khng pht hin.

V tr ly mu: Khu vc khai thc ct Long Ha IV vi cc ta c th:

N1: Khu vc d n - X: 1146500; Y: 0714250; N2: Khu vc d n - X: 1146500; Y: 0715250; N3: Khu vc d n - X: 1145500; Y: 0714250.Nhn xt: Qua kt qu phn tch cho thy, ngoi tr cc ch tiu nh TSS, DO COD, Fe, Mn, Zn, Coliform mt s v tr ly mu vt quy chun quy nh (QCVN 10:2008/BTNMT), tt c cc ch tiu cn li u t quy chun quy nh. Nhn chung, mc nhim khng cao do vic ci thin cht lng nc hon ton c th c khc phc. 2.1.3.3. Hin trng thy sinh vt

Nhm kho st tin hnh thu mu ti 6 im trong khu vc d n kho st thnh phn cu trc v s lng cc loi thy sinh, l ngun thc n cho c ng thi cng l nhng sinh vt ch th nhim. Kt qu kho st nh sau:

a. Thc vt phiu sinh

c tnh thnh phn loi

Kt qu phn tch ghi nhn c 72 loi thuc 3 ngnh thc vt phiu sinh khu vc kho st. Trong , ngnh Chrysophyta chim s lng loi cao nht (63 loi), ngnh Dinophyta c 8 loi v ngnh Cyanophyta ch c 1 loi (Bng 1)

Bng 2.3. Cu trc s loi cc ngnh to khu vc kho stNgnhS loiT l (%)

Cyanophyta11,4

Chrysophyta6387,5

Dinophyta811,1

Tng cng71100

(Ngun: Vin Nc & CNMT WETI, 05/2008)

Tt c cc loi thc vt phiu sinh ghi nhn c c ngun gc nc l, mn ca vng ca sng, ven bin. iu ny th hin c im mi trng nc khu vc kho st l nc l mn. Mt s loi to tm thy thch ng v pht trin mnh trong iu kin giu dinh dng hu c nh Skeletonema costatum, Chaetoceros compactum, Chaetoceros subtilis. Ring loi Skeletonema costatum v Ceratium furca thng n hoa trong iu kin ph dng, lm thit hi ti nguyn thy sn, suy gim h sinh thi v cht lng mi trng ven bin.Cc im thu mu u hin din Pseudonitzschia sp, l nhm loi to c kh nng gy c ca bin. Nhm to Pseudonitzschia (l thc n ca nhuyn th nh nghu) c kh nng tit ra c t ASP (Amnesic Shellfish poinsoning). c t ASP khng c tc dng trn nhuyn th nhng li gy c i vi ng vt v con ngi. Ngi b ng c thng b bun nn, au u, tiu chy. ASP khng mu, khng mi, bn vi nhit v cha c thuc c tr. V vy vn to c kh nng gy c v c t ca chng l mt vn cn c quan tm nhiu v l do sc khe cng ng v ngun li thy sn.

S loi thc vt phiu sinh tng im kho st bin thin t 32 51 loi. Nhn chung cc gi tr ny khng cao trong iu kin nc l mn, mn. Tuy vy n c th l kt qu t s nh hng ca hm lng cht l lng cao trong mi trng nc khu vc kho st.

c tnh s lng v loi u th nht

S lng thc vt phiu sinh c gi tr t 415.000 3.590.000 c th/lt. y l cc gi tr nm trong khong t trung bnh n hi cao. Ton khu vc kho st ch c 1 loi to u th l Skeletonema costatum. iu ny gp phn th hin tnh ng nht v mi trng nc v c im giu dinh dng hu c trong vng kho st.

Cc ch s

a dng thc vt phiu sinh khu vc kho st (Bng 4) c gi tr t 0,51 1,97, th hin mi trng nc thuc loi giu dinh dng hu c.

Bng 2.4. a dng thc vt phiu sinh khu vc kho stTrm123456

H'0,511,971,160,831,690,72

Ch s u th thc vt phiu sinh c gi tr t trung bnh n cao (Bng 5). iu ny th hin s n nh khng cao trong cn bng qun x thc vt phiu sinh.

Bng 2.5. Ch s u th thc vt phiu sinh khu vc kho st

Trm123456

D0,620,460,440,750,530,54

b. ng vt phiu sinh

c tnh thnh phn loi

Kt qu phn tch ghi nhn c 39 loi v 6 dng u trng ng vt phiu sinh. Thnh phn loi phn b theo 22 h, thuc 7 nhm ngnh chnh vi t l theo Bng6.

Bng 2.6. Cu trc s loi cc nhm ng vt phiu sinh khu vc kho st

Nhm/ngnhS loi%

Copepoda2862,2

Coelenterata12,2

Mysidacea12,2

Prochordata24,4

Ostracoda12,2

Protozoa613,3

Larva613,3

Tng cng45100

(Ngun: Vin Nc & CNMT WETI, 05/2008)

Cu trc thnh phn loi th hin c tnh mi trng nc l mn vi cc loi ngun gc nc mn v ca sng ven bin, c bit l nhm gip xc chn cho Copepoda, chim t l hin din u th trong ton h (28 loi - 62,2%).

Cc nhm loi c trng cho mi trng nc giu dinh dng, nhiu cht vn hu c thuc Copepoda v Protozoa c ghi nhn hu ht cc trm kho st.

S lng loi hin din khng c s khc bit cao gia cc im kho st, bin thin t 31 loi (im 5) n 37 loi (im 6).

c tnh s lng v loi u th nht

S lng c th ng vt phiu sinh bin thin t 43.700 61.300 (c th/m3), cao nht ti im thu mu 6 v thp nht ti im 5.

Thnh phn loi u th bao gm cc loi c trng cho mi trng giu dinh dng thuc h Acartiidae, Oithonidae (Copepoda) v cc dng u trng Nauplius ca chng. S hin din thnh phn loi u th gia cc trm tng i ng nht, th hin tnh ng nht trong pht trin ca khu h ng vt phiu sinh vng kho st.

Cc ch s

Ch s a dng (H) ti cc im thu mu bin thin t 1,584 2,314, cao nht ti trm 1 v thp nht ti trm 3 cao nht ti trm 1 v thp nht ti trm 3. Nhn chung, gi tr a dng ti vng kho st tng i thp, th hin mc tc ng ca cc tc nhn mi trng n phong ph ca khu h ng vt phiu sinh ti y.

Bng 2.7. a dng ng vt phiu sinh khu vc kho stTrm123456

H2,3141,9591,5841,7501,6991,805

Ch s u th (D) bin thin t 0,30 0,46, cao nht ti im thu mu 5 v thp nht ti im 1.

Gi tr u th ti cc im thu mu nhn chung tng i thp, th hin c tnh pht trin tng i n nh ca khu h ng vt phiu sinh vng kho st.

Bng 2.8. Ch s u th ng vt phiu sinh khu vc kho st

Trm123456

D0,300,390,410,380,460,37

c. ng vt khng xng sng c ln y

c tnh thnh phn loi

Kt qu phn tch ghi nhn c 11 loi VKXSCL khu vc kho st. Trong , giun nhiu t (Polychaeta) chim s lng loi cao nht (7 loi), hai mnh v (Bivalvia) c 2 loi v gip xc (Crustacea) c 2 loi (Bng 9)

Bng 2.9. Cu trc s loi VKXSCL khu vc kho st

NgnhS loiT l (%)

Polyacheata763,6

Mollusca218,2

Crustacea218,2

Tng cng11100

Tt c cc loi VKXSCL ghi nhn c c ngun gc nc l, mn ca vng ca sng, ven bin. iu ny th hin c im mi trng nc khu vc kho st l nc l mn.

Mt s loi VKXSCL tm thy thch ng v pht trin mnh trong iu kin giu dinh dng hu c nh Scoloplos armiger, Prionospio malmgreni, Prionospio sp. Owenia fusiformis. Nhng loi c th pht trin vi s lng rt cao cc khu vc b nhim cao ca sng Th Vi.S loi VKXSCL tng im kho st bin thin t 3 6 loi. S loi cao nht im 2 v thp nht im 2 (khu vc y ct rn hn ch s pht trin ca nhm loi ny).

c tnh s lng v loi u th nht

S lng VKXSCL c gi tr t 40 120 c th/m2, cho thy mt c th khu vc kho st tng i thp. Cc loi giun nhiu t sng nh c Scoloplos armiger, Prionospio malmgreni, Owenia fusiformis chim u th.

a dng VKXSCL khu vc kho st (Bng 10) c gi tr t 0,104 1,68, nhng gi tr ny khng cao th hin nh hng mnh ca ng lc bin n khu h VKXSCL.

Bng 2.10. a dng VKXSCL khu vc kho stTrm123456

H'1,411,681,241,331,041,33

Ch s u th VKXSCL c gi tr bin thin t 0,33 0,50 (Bng 11).

Bng 2.11. Ch s u th VKXSCL khu vc kho st

Trm123456

D0,450,330,500,400,500,40

Kt lun

Kt qu phn tch khu h thy sinh vt th hin tnh cht mi trng nc khu vc kho st l nc l, mn v giu cht dinh dng. Ngoi ra, khu vc ny cn b tc ng mnh ca ng lc bin lm cho tng c ca khu vc kho st.

2.2. IU KIN KINH T - X HI 2.2.1. iu kin kinh t

2.2.1.1. Sn xut nng nghip

Thy sn: nm 2009, tng sn lng thy hi sn khai thc c t 31.920 tn, tng ng vi tng gi tr sn lng 698.438 triu ng, trong nh bt 20.653 tn, nui trng 11.266 tn.

Chuyn i c cu sn xut (cy trng, vt nui)trn din tch t nng nghip 4 x pha Bc trong nm 2009 t 1.548ha. Trong nm c 5.475,7 ha th nui 777 triu tm ging, trong nui qung canh chim 61,2% din tch th nui; c 5255,8 ha thu hoch (chim 96% din tch th nui) t sn lng 6292,9 tn tm thng phm (tm th chn trng 3.318 tn, tm s 2.974 tn).

Chn nui: Gi tr sn lng chn nui t 9.140 triu ng, chim t trng 51,4% trong c cu ngnh. Duy tr pht trin n chn nui gia sc vi khong 4.839 con, thng xuyn tng cng cng tc kim tra phng chng dch gia cm, t chc tim vacxin phng nga bnh gia sc trn cc a bn cc x, th trn.Dim nghip: do thi tit thun li nn v mui 2008 2009 t tng sn lng thu hoch l 65.256 tn trn din tch 1.516 ha. Hin nay, huyn ang khuyn khch pht trin din tch lun canh nui thy sn mui hoc mui nui Artemia nng cao hiu qu u t sn xut.

2.2.1.2. Cng nghip Xy dng Cng nghip tiu th cng nghip: nm 2009 ngnh cng nghip tiu th cng nghip vn cha c yu t pht trin t bin. Gi tr sn xut ton ngnh t 116.300 triu ng tng 28% so vi cng k, trong khu vc kinh t quc doang tng 13% trong khi khu vc kinh t ngoi quc doanh tng 7%.

u t xy dng: tng mc u t ton x hi c t 1.305,3 t ng, tng 61% so vi cng k. Tng vn u t chia theo lnh vc: u t pht trin sn xut (k c u t thy li phc v sn xut) 245,8 t ng; u t kt cu h tng 1.059,5 t ng gm u t c s vt cht phc v pht trin gip dc vn ha x hi trn 63.895 triu ng, u t pht trin h tng giao thng hn 128.760 triu ng v cn li u t cho cng tc qun l, chm sc, bo v rng, u t pht trin nh , tr s c quan,

Thng mi dch v: Tng doanh s bn hng ha v cung ng dch v t 2.518 t ng tng 14% so vi cng k, trong doanh s bn ca ngnh thng mi, dch v tng 14% v n ung tng 10% so vi cng k. Ton huyn c 48 c s kinh doanh dch v du lch tp trung ch yu ti Khu du lch 30/4, trong nm n tip khong 400.000 lt n tham quan, vui chi gii tr. Giao thng vn ti: c tng doanh thu ngnh giao thng vn ti t 265,4 triu ng (GC 94), khi lng hng ha vn chuyn 14,2 triu tn t mc lun chuyn 109,2 triu tn km. Khi lng hnh khch vn chuyn 15,7 triu hnh khch t mc lun chuyn 219,2 triu hnh khch km. Bu chnh vin thng: tng doanh thu t 3.915 triu ng, trong nm ngnh bu in t chc lp t trn 200 my in thoi c nh, hin mt thu bao in thoi t 53,57 my/100 dn, tng gp 2 ln so vi thi im nm 2005.2.2.2. iu kin v x hi Gio dc o to: Nm 2009 2010 ton huyn c 15.952 hc sinh cc cp c huy ng ra lp, 6 tui vo lp 1 t 100%, hc sinh lp 5 hon thnh chng trnh tiu hc ra lp 6 t 98,6%, hc sinh tt nghip trung hc c s ra lp 10 t 96,42%. n cui nm 2009, trnh hc vn ca huyn t 8,2 lp.

Y t: trong nm, bnh vin v h thng c s y t ca huyn t chc khm v iu tr cho 224.729 lt ngi. Tip tc tng cng cng tc chm sc sc khe ban u v thc hin tt cng tc x hi chm sc sc khe cho ngi ngho, i tng chnh sch; ko gim t l suy dinh dng tr em xung cn 6,98% so vi nm 2008, tim chng m rng 6 mi cho tr trong tui t 97,98%.

Vn ha thng tin: tip tc xy dng v phin phong tro qun chng cc x, th trn, tranh th cc dp l hi kt hp vi mi quan h gia cc a phng, n v bn kt ngha t chc cc bui hi thi, biu din giao lu, ph v nhu cu th hng vn ha tinh thn cho nhn dn a phng. Nm 2009 t chc 42 sut din ngh thut chuyn nghip v nhiu sut din qun chng phc v cho hn 2.700 lt ngi xem cc x, th trn.

Hot ng th dc, th thao: phong tro th dc th thao qun chng nhn dn ngy cng c nng ln, t l ngi dn tham gia luyn tp thng xuyn t 21,6%, c 14,53% s h gia nh t tiu chun gia nh th thao. Tnh n nay, ton huyn c 409 c s hot ng th dc th thao.

Dn s v lao ng: n 01/04/2009, tng dn s Cn Gi 68.213 ngi v ton huyn gii quyt vic lm cho 4.593 lao ng, trong gii quyt vic lm n nh 3.123 lao ng.

Quc phng an ninh: tip tc duy tr thng xuyn ch thng tin, giao ban nh k vi cc a bn gip ranh trong cm phng th. Hon thnh ch tiu giao qun ngha v qun s t I nm 2009. T chc hun luyn lc lng dn qun t v trn a bn. Tnh hnh an ninh chnh tr v trt t an ton x hi tip tc c gi vng. Phong tro qun chng tham gia bo v an ninh T quc thng xuyn thc hin, nng cao thc ngi dn trong vic t gic ti phm.CHNG 3 NH GI CC TC NG MI TRNG

3.1. NH GI TC NG 3.1.1. Ngun gy tc ng c lin quan n cht thi3.1.1.1. Giai on thm d, ly mu

Mc tiu ca giai on ny l xc nh b dy thn ct, tin hnh ly mu phn tch cht lng ct theo chiu su, t nh gi cht lng v tr lng ct trong din tch thm d. y l mt cng on rt kh khn v phc tp v phi ly c mu nguyn dng ca cc lp ct b, ri, c bit i vi tng ct ti, xp mi c bi lng.

Cng tc khoan ly mu c thc hin bng thit b khoan thy kh (air-lift) do trng i hc Bch Khoa thit k.a. Ngun tc ng n mi trng nc mt

Lng mu tha t qu trnh ly mu thm d v phn tch

Cng ngh thm d ch yu l khoan ct v ly mu bng cc gin khoan ni c gn trn b, tho rp ri khi di chuyn bng cc phng tin ng thy. Qu trnh ny c th xy ra hin tng trn, xng, du my.

Nc thi sinh hot t hot ng cng nhn.

R r du my ra bin khi vn hnh my mc

Cht thi rn sinh hot ca cng nhn lm vic trn tu

Cht thi nguy hi: cn du nht, gi lau my mc c dnh du, nht.b. Ngun tc ng n mi trng khng kh

nhim do kh thi ra (bi, CO, SOx, NOx, THC, Pb, .) t cc phng tin thm d, phng tin v my mc thi cng.

3.1.1.2. Trong giai on hot ng d n

a. Ngun tc ng n mi trng nc mt

Nc thi sinh hot ca cng nhn lm vic trn tu khai thc ct (v sinh, tm git, nh bp)

Nc ma b nhim du do lng du my b r r ra ngoi v b nc ma chy trn trn sn tu cun tri xung bin

Qu trnh np v lu tr nhin liu c th xy ra r r du

Cht thi rn sinh hot ca cng nhn lm vic trn tu

Cht thi nguy hi: cn du nht, gi lau my mc c dnh du, nht.b. Ngun tc ng n h sinh thi bin v i sng thy sinh

Khai thc ct bng vi ht thy lc c th to nn dng nc xoy lm nh hng ti s pht trin ca sinh vt, nht l sinh vt y. S c b ng ng dn ct lm c nc cng gy ra xo trn ln cho i sng sinh vt cng nh hot ng sng dn c quanh vng.

c. Ngun tc ng n mi trng khng kh

nhim khng kh v bi sinh ra do hot ng ca ng c tu, my pht in v sinh hot trn tu khai thc ct.

3.1.2. Ngun gy tc ng khng lin quan n cht thi:3.1.2.1. Giai on thm d, ly mu

Khi thi cng cc l khoan, b khoan phi neo u c nh nn t nhiu nh hng n vic lu thng ca cc phng tin ng thy.

nhim ting n v chn ng do hot ng ca ng c ghe tu, my khoan v cc phng tin, my mc thi cng. Cc hot ng khoan thm d u c thc hin trn bin nn nguy c xy ra lt, chm tu, hoc cc tai nn lao ng trn bin khc.

Chy n

3.1.2.2. Giai on hot ng d n

Bin ng v gi tr s dng ca ti nguyn t do thay i mc ch s dng. Mt lng bn ct y bin s b mt i v b li chng y lng bn ct c hnh thnh pha b ln bin dc mt bi ti a cho php sau ci to vt qu dc tnh ton cho php gy st l v ct chy. Hot ng khai thc ct tin hnh lin tc trn tuyn ng giao thng thy gy nn cn tr giao thng thy

Bm ht ct v san lp ct to nn s xo ng y bin v xi l ng b

Chy n Tai nn lao ng

3.1.3. i tng v quy m b tc ng3.1.3.1. i tng b tc ng

Mi trng vt l:

Khng kh

Nc bin ven b Mi trng sinh hc: H thy sinh

Mi trng kinh t - x hi

Giao thng thy Tai nn lao ng

Chy n

3.1.3.2. Quy m b tc ng

Cc tiu ch xc nh quy m tc ng ca d n:

Bng 3.1. Tiu ch nh gi quy m tc ngThi gian Tc ng ko di

KhngKhng tc ng

Ngn Ngn hn 1 nm

Trung bnhT 1 n 10 nm

Di Hn 10 nm

Vnh vinKhng th phc hi

Mc - Hu qu tc ng n ton b thnh phn mi trng ang xem xt

KhngKhng tc ng

NhPhn b nh hng t hn 1% ton b

Trung bnhPhn b nh hng t 1% - 10% ton b

LnPhn nh hng trn 10% ton b

Phm vi tc ng Quy m v mt khng gian vng b nh hng, lin quan n cc tc ng tch ly n tc ng xuyn bin gii

a phngnh hng nm trong khu vc d n

Vng/quc giaC nh hng lin vng, lin tnh

Quc tC nh hng xuyn bin gii

Loi tc ng Phn loi tc ng

Trc tipnh hng trc tip v xy ra ng thi vi hot ng ca d n

Gin tipnh hng c lin quan n d n v xy ra chm hn so vi cc hot ng ca d n hoc phm vi bn ngoi khu vc chu nh hng trc tip

Tch lynh hng t t hp cc tc ng ca d n vi cc tc ng ca d n ln cn v cc d n quy hoch

Kh nng xy ra Xc sut xy ra tc ng

Thp< 25%

Trung bnh25 75%

Cao> 75%

Trn c s tiu ch c th hin Bng 3.1 - Tiu ch nh gi quy m tc ng, quy m tc ng ca d n c nhn nh nh sau:Bng 3.2. Quy m tc ng do hot ng trin khai d nSTTi tng chu tc ngTc nhnQuy m tc ng

1. Giai on thm d, ly mu

1.1Mi trng vt l

Khng khKh thi v bi t cc phng tin thm d, phng tin v my mc thi cngThi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

Ting n v chn ng do hot ng ca ng c ghe tu, my khoan v cc phng tin, my mc thi cngThi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

Nc bin ven bNc thi sinh hotThi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

Cht thi rn sinh hotThi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

Cht thi nguy hiThi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Trung bnh

Lng mu tha t qu trnh ly mu thm d v phn tchThi gian: Trung bnh

Mc : Nh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Thp

Xng du r r Thi gian: Trung bnh

Mc : Ln

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

1.2Mi trng sinh hc

H thy sinhNc thi sinh hotThi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

Cht thi rn sinh hotThi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

Xng du r rThi gian: Trung bnh

Mc : Ln

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

Cht thi nguy hiThi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Trung bnh

1.3Mi trng kinh t - x hi

Cn tr giao thng bin ven bThi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Gin tip

Kh nng xy ra: Trung bnh

Chy nThi gian: Trung bnh

Mc : Ln

Phm vi: a phng

Loi: Gin tip

Kh nng xy ra: Cao

Tai nn lao ngThi gian: Ngn

Mc : Ln

Phm vi: a phng

Loi: Gin tip

Kh nng xy ra: Trung bnh

2. Giai on hot ng

2.1Mi trng vt l

Khng khKh thi t my pht in Thi gian: Ngn

Mc : Ln

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Trung bnh

Bi v kh thi t cc phng tin vn chuynThi gian: Di

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

Ting n t ng c tu, thit b ht, my pht inThi gian: Di

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

S c chy nThi gian: Ngn

Mc : Ln

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

Nc bin ven bNc thi sinh hotThi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

Cht thi rn sinh hotThi gian: Di

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

Cht thi nguy hi (cc gi lau my mc c dnh du nht)Thi gian: Trung bnh

Mc : Cao

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Trung bnh

Trn xng, du t qu trnh np nhin liu, vn chuynThi gian: Di

Mc : Cao

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

ng bXi l ng b

Thi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Trung bnh

y binS xo ng y bin t vic bm ht ct v san lp ctThi gian:Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Trung bnh

dc mt bi ti a cho php sau ci to vt qu dc tnh ton cho phpThi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Trung bnh

Mi trng sinh hc

H thy sinhNc thi sinh hotThi gian: Di

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

Cht thi rn sinh hotThi gian: Di

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

Xng du r rThi gian: Di

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

Khai thc ct bng vi ht thy lc c th to nn dng nc xoyThi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Cao

S c b ng ng dn ct lm c ncThi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Trc tip

Kh nng xy ra: Trung bnh

Mi trng kinh t - x hi

Cn tr giao thng bin ven bThi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Gin tip

Kh nng xy ra: Trung bnh

Bin ng v gi tr s dng ca ti nguyn t do thay i mc ch s dng.Thi gian: Trung bnh

Mc : Trung bnh

Phm vi: a phng

Loi: Gin tip

Kh nng xy ra: Trung bnh

Chy nThi gian: Trung bnh

Mc : Ln

Phm vi: a phng

Loi: Gin tip

Kh nng xy ra: Cao

Tai nn lao ngThi gian: Ngn

Mc : Ln

Phm vi: a phng

Loi: Gin tip

Kh nng xy ra: Trung bnh

3.1.4. nh gi cc tc ng

Trong cc giai on khoan thm d cng nh giai on khai thc ct phc v cho cng tc san lp mt bng pht sinh nhiu tc ng tiu cc n mi trng cng nh h sinh thi ti khu vc d n m Long Ha IV. Ty theo tn sut, quy m cng nh c tnh m mi tc ng c d bo phn trn s c mc nh hng, kh nng gy nguy hi n mi trng, i sng thy sinh, h sinh thi khu vc cng nh n i sng v sc khe ca con ngi mt cch khc nhau.

3.1.4.1. Tc ng n mi trng trong giai on thm d

a. Tc ng n mi trng nc mt

Quy trnh ly mu c thc hin theo ch ly mu rnh: sn phm trong mi hip khoan gm hn hp nc + ct si ln bn, st, mica v mn thc vt c hng trong cc thng nh. Sau khi lng nc, sn phm c tch ri khi nc, trn u vi nhau v trch mt phn cho vo ti mu v vy sau khi ly mu em i phn tch, lng mu tha c tr li bin c th lm c nc, nh hng n i sng ca cc thy sinh vt. Tuy nhin, lng mu tha khng nhiu do s nh hng khng ng k n i sng thy sinh.

Trong qu trnh khoan thm d ly mu, ch thu thc hin khng s dng st khoan, m dung dch s dng l nc lnh bn cht khng khc g nc bin nn khng lm xo ng v nh hng n mi trng nc.

Nc thi pht sinh do sinh hot ca cng nhn trn tu khoan thm d ch yu l cht cn b, du m, cc cht hu c, cc cht dinh dng v vi sinh,gy nh hng khng tt n cht lng cc b nc bin nu khng c x l. Theo tiu chun thit k (TCXD 33:2006), tiu chun dng nc i vi cng nhn lm vic khong 22 45 lt/ngy. Chn tiu chun cp nc 45 lt/ngy. Lu lng nc thi sinh hot tnh bng 80% lng nc cp. Nh vy vi lng cng nhn tham gia hot ng thm d khong 10 ngi th lu lng nc thi sinh hot d kin ch khong 0,4 m3/ngy.

Nc thi sinh hot ch yu nhim bn cc cht hu c v vi sinh vt, ring nc thi t hot ng nu nng c hm lng du m v cc cht rn l lng tng i cao, theo (Hong Vn Hu, 2002) c tnh nng cc cht nhim c bn trong nc thi sinh hot tnh theo u ngi c dn ra trong bng sau:

Bng 3.3. Nng cc cht nhim c bn trong nc thi sinh hotCc ch tiuNng bn

(g/ngi.ng.)Nng bn ca 10 cng nhn trn tu (g/ngi.ng.)

SS65650

BOD5 ( lng)35350

Nit ca mui amn880

Cht hot ng b mt2,5 25

Cho thy lng nc pht sinh cng nh nng bn ca cht nhim trong qu trnh thm d khng ln nn tc ng ca n khng ng k v ch trong thi gian tng i ngn.Nc ma chy trn c th cun theo cc cht nhim trn sn tu khoan thm d nh du, m, ct,xung bin gy nhim bn nu sn tu khng c b tr gn gng ngn np v lm v sinh sch s. Hin tng ny lm tng c vng nc bin ti khu vc thm d, ngn cn qu trnh ha tan oxy vo nc v tc ng xu n h sinh thi thu sinh.

b. Tc ng n mi trng khng kh

Trong qu trnh khoan thm d s pht sinh ting n t ng c ca tu khoan thm d, ng c my bm, my nn kh phc v cho cng tc khoan. V v tr d n nm ngoi khi cch xa t lin nn vn nh hng n khu vc xung quanh l hon ton khng xy ra. Tuy nhin, ting n c th lm nh hng n mt s loi thy sinh ti khu vc d n. Ngoi ra ting n cng c th nh hng trc tip n sc khe ca ngi cng nhn vn hnh gin khoan thm d nu khng c trang b phng tin bo h lao ng.

Kh thi pht sinh t ng c ca tu khoan thm d vi thnh phn tnh cht nh sau: gm bi, CO, SOx, NOx, THC, Pb, .

Ty thuc vo thnh phn, tnh cht v nng cc cht gy nhim khng kh cng nh thi gian tc ng, cc cht nhim ny c th gy ra mt s tc ng tiu cc ln sc kho ngi trc tip lao ng nh vim ng h hp, bnh phi (ph phi, ung th phi) v cc bnh v tim mch, Tuy nhin ng c tu c t xa ngi cng nhn v khi thi c d dng pht tn nhanh trong khng gian trng tri nn hu nh hon ton khng nh hng n mi trng v con ngi.

c. Ngun tc ng t cht thi rn v cht thi nguy hi

Rc thi sinh hot nu khng c thu gom v tp trung ng v tr c th gy vng vi trn thuyn khai thc cng nh c th b ri xung bin lm nh hng n ngun nc bin, cc loi thy sinh v gy mt m quan ti khu vc.

Lng cht thi nguy hi pht sinh nh : cn du nht, cc gi lau dnh du nu khng c thu gom ng theo quy nh, vng vi ba bi c th b ri xung bin do bt cn hoc do ma chy trn cun tri xung s lm vng nc bin ti khu vc b nhim du, c th gy nh hng n i sng ca cc loi thy sinh. Hn na, cn du chy hay r r trn sn nu khng c thu gom hay v sinh kp thi c th lm ngi cng nhn b t ng do trn trt, nguy him n sc khe v tnh mng, c bit c th ri xung bin nu bt cn.

Tuy nhin giai on khoan thm d ch din ra trong thi gian ngn nn tc ng tiu cc ca n n mi trng l khng ng k v c th kim sot mt cch d dng.

3.1.3.2. Tc ng n mi trng trong giai on khai thc

Vic nh gi tc ng ca vic khai thc ct bin cng nh quan trc mi trng nhng khu vc khai thc ct cho php chng ta theo di hnh dng ca cc h ct v mi quan h ca chng vi cc yu t vt l nh sng, dng chy, hnh dng vt l, dc nn y, kch thc ht bn y...Chng ta cn phi d an cc tc ng lu di n khu vc khai thc ct cng nh khu vc san lp trnh cc nh hng xu c th gy ra do vic khai thc v san lp ct.

Tc ng n mi trng trong giai on khai thc ct cn quan tm v theo di l : cc tc ng ln mi trng nc lm ri lon dng chy, xi l b, xm thc y sng lm nh hng n thy sinh trong khu vc,

a. Tc ng n mi trng nc mt

Phng tin khai thc ct ca d n l tu ht phun Vit M (Ellicott) cng sut 4170 CV, nng sut 1500m3/gi . Khi tu hot ng, cc trm tch y bin ti khu vc ming ht ca tu s b khuy ng, nc bin s b c v mang theo mt s thnh phn nhim hin c trong cc lp trm tch b khuy ng dch chuyn theo dng triu. Ti khu vc ming thi ca tu ht mt lng nc bn c cha cc thnh phn nhim s rt khi lp ct chy ngc ra pha bin v sau theo dng triu lan truyn n cc khu vc ln cn.

Do b khuy ng, cc cht nhim ngun nc khng ch tp trung khu vc cng trng m cn c th lan truyn sang cc khu vc ln cn theo dng triu trong cc pha triu ln. Cc khu vc c kh nng b nh hng l khu vc ca sng Dinh B (nhnh ca sng Ng By), rch Ba Gian (rch L - gn bi 30/4), vng H Thanh.

Tuy nhin khu vc d n nm lt gia trung tm bi bi Cn Gi, tc dng chy khu vc ny kh thp so vi khu vc ca sng Soi Rp v ng Tranh hai bn, do vy nc bn nhim s c khuynh hng lng ng li ngay trn phm vi bi bi v hai pha ca khu vc thi cng, khng c nhiu kh nng lan truyn n khu vc ca sng, nh vy cc nguy c lan truyn nhim theo dng triu vo sng rch n khu rng ngp mn hay cc khu nui trng thy sn Cn Gi l rt thp (tng hp t Bi Lai (1995), Nghin cu khai thc s dng hp l cc h sinh thi ca sng ng Nai Si Gn, ti nhnh KT 03 11 ti cc tnh pha Nam, Vin sinh hc nhit i, TP.HCM), (Lm Minh Trit (2002), Bo co TM d n h thng cng trnh ln bin v khu th du lch bin Cn Gi, Vin Mi trng v ti nguyn, TP.HCM).

Theo kt qu kho st th mi trng nc ti khu vc d n giu dinh dng do tm thy mt s loi to v mt s loi ng vt khng xng sng c ln pht trin mnh trong iu kin giu dinh dng hu c nh Skeletonema costatum, Chaetoceros compactum, Chaetoceros subtilis, Nitzschia spp. Ring loi Skeletonema costatum v Ceratium furca thng n hoa trong iu kin ph dng, lm thit hi ti nguyn thy sn, suy gim h sinh thi v cht lng mi trng ven bin. Nhn chung cc gi tr ny khng cao trong iu kin nc l nc mn. Tuy vy n c th l kt qu t s nh hng ca hm lng cht l lng cao trong mi trng nc khu vc kho st (Chi tit trong phn ph lc)

Do trong mi trng giu cht dinh dng nn vic x thi cc cht thi sinh hot ca cng nhn trn tu s lm cho mi trng nc b nhim hn, nc thi sinh hot s c thu gom li v x l trc khi x vo mi trng, rc thi sinh hot ca cng nhn s c tp trung vo thng rc v c chuyn vo b x l

Lng nc thi sinh hot d kin pht sinh trn mi tu l 5,04 m3/ngy.m. Xt v thnh phn v tnh cht, nc thi sinh hot ca cng nhn, thuyn vin trn tu khai thc ct b nhim bi cn b hu c, cht l lng v cc cht hu c v cc cht dinh dng, nu khng c x l hoc x l cha t tiu chun, nc thi sinh hot ca d n s gp phn lm gia tng mc nhim ti khu vc khai thc, c bit l nhim cht hu c.

Ngoi ra, c kh nng r r du nht cng gy nhim n mi trng khu vc. nh hng ca du, xng, du bi trn n nc th hin ch lm gim tnh cht ha l ca nc (lm bn, thay i mu, mi v), lm cc cht c d tan vo nc, to lp vng trn b mt lm gim hm lng oxy trong nc, cn tr s trao i nhit cng nh to ra lp cn y. Do tnh c hi v tnh bn vng ca cht nhim bn ny m c th dn n nhng nh hng i vi ng thc vt c nhy cm cao sng trong nc. Qun th sinh vt sng trong nc b nhim bn s gim xung rt nhanh, vi hm lng 20 30 mg/l th cc hot ng thuc v phn x c iu kin ca c b ri lon v nu ln hn c th gy cht c.

Tm li, mc d c mt s tc ng tiu cc nht nh n mi trng nc trong qu trnh hot ng khai thc lin tc song chng ch din ra trong thi gian ngn (6 thng); v vy cc tc ng ny s bin mt khi hot ng khai thc ct ngng hot ng.

Ngoi ra cng cn phi lu rng cc vn nhim mi trng nc khu vc d n cng nh khu vc ph cn hin ti cng nh trong tng lai hon ton do cc tc ng tng hp ca nhiu loi hnh hot ng kinh t - x hi ang din ra ht sc mnh m pha thng ngun.

b. Tc ng n ti nguyn sinh vt

Cc hot ng ca d n lin quan n vic thay i mi trng nc u gy tc ng mc khc nhau i vi dng ti nguyn thy sinh trong vng chu nh hng ca s thay i mi trng nc.

Vic thi cng cc hng mc cng trnh nh o p t, k c th gy bin dng mi trng sng ca mt s thc vt, thu sinh vt v thu sn trong vng d n. Chng c th cht hoc di chuyn n ni khc. Tuy nhin tc ng ny khng ln v din tch khu vc chu nh hng ca d n tng i nh so vi vng ca sng vng bin Cn Gi.Khi thi cng ln bin hon thnh c th xy ra hin tng lng ng ph sa t dng ni a v lng ng cht l lng. Vi trng hp ny nghu khng pht trin c nh hin nay, nhng ngc li s huyt li thch nghi, iu ny nh hng trc tip n ngh nui nghu ven bin Cn Thnh, Long Ha v nui s huyt ca sng Mi Nai.

Hot ng ca vic khai thc ct phc v d n Khu th du lch ln bin Cn Gi vi phng php khai thc hin i c kh nng hn ch n mc thp nht nhng tc ng n h sinh vt bin. Tuy nhin, hot ng khai thc ny trong chng mc no c th c nhng nh hng n h thy sinh trong khu vc d n.

Hot ng khai thc ct c th gy tc ng nht thi lin quan n mc tng nng bn, cn l lng trong nc bin khu vc khai thc; nh hng nht thi n h sinh vt bin: nh hng n qu trnh h hp ca cc loi hi sn (mt s loi thy sinh khu vc ln cn khu vc khai thc ct nh tm c, mt s loi ng vt thn mm c kh nng lt xc v ng c v (nghu) rt nhy cm vi s thay i dng chy v cht lng mi trng nc) dn n kh nng di chuyn tm thi khi vng khai thc.

Tuy nhin qu trnh khai thc ch gii hn trong mt thi gian nht nh, khi kt thc giai on khai thc, s dn phc hi li trng thi t nhin ban u ca vng khai thc v iu kin mi trng cng dn tr li trng thi ban u.

Thc ra, hot ng khai thc ct ch gy khuy ng bn ct t nhin ca vng khai thc, khng c hin tng gy nhim c trng ng k no c th nh hng xu n t nguyn sinh vt bin, c chng ch l nhng nh hng c tnh tc thi i vi mt s loi hi sinh nhy cm vi mi trng thay i.c.Tc ng n mi trng khng kh

Trong qu trnh khai thc ct din ra, cc ngun gy nhim khng kh ch yu l kh thi v ting n t hot ng ca tu ht bn c th gy nh hng xu n sc khe ca cng nhn. Tuy nhin, tu ht ct s dng cho d n l tu c ng mi ca H Lan v Hn Quc, tnh trng hot ng rt tt do cng s hn ch vn ting n v khi bi pht sinh khi tu hot ng.

nhim bi trong qu trnh y ct t tu ht vo khu vc cn san lp, thi cng cc hng mc cng trnh nh xy dng bao khu vc cn san lp c th tc ng ln ngi cng nhn trc tip lm vic ti cng trnh v ln mi trng xung quanh (dn c, h ng thc vt). Tuy nhin, do phn ln cc hng mc cng trnh u nm trong vng t m t nn cc tc ng do bi gy ra l khng ng k.

Hn th na cc ngun nhim ny phn tn trong mt mi trng rng, thong, cch xa khu dn c v khu h ng thc vt, do c th khng nh cc tc ng ca chng gy ra i vi con ngi v mi trng l khng ng k.

d. Tc ng ca cht thi rn v cht thi nguy hi

Cht thi rn pht sinh trong qu trnh hot ng ca d n ch yu l cht thi sinh hot, ch yu l rc thi t hot ng nu n ca cng nhn trn tu khai thc (thc n tha, bao b, v hp,) lng rc ny nu khng c thu gom tt s gp phn lm nhim hu c, lm tng hm lng cht l lng trong nc bin trong khu vc.

e. Tc ng n mi trng t

Mt lng bn ct y bin s b mt i v b li chng y lng bn ct c hnh thnh pha b ln bin, iu ny khng gy ra nhng vn g ln lin quan n ti nguyn t ngoi tr s bin ng v gi tr s dng ca ti nguyn t do thay i mc ch s dng.

Hin tng st l v ct chy c th xy ra khi dc mt bi ti a cho php sau ci to vt qu dc tnh ton cho php.

Cc cht thi rn sinh hot pht sinh trong qu trnh thc hin d n nu khng c cc bin php thu gom v b tr ni tp trung hp l cng s gy nhng nh hng xu n mi trng xung quanh.

f. Tc ng n giao thng thy

Hot ng khai thc ct tin hnh lin tc trn tuyn ng giao thng thy c th cn tr s i li ca tu b nhng khi nhn vo bn (topographic map of Can Gio off - shore) phn ph lc thy r khu vc khai thc ct khng nh hng tuyn lu thng ca tu (ng ng tr ca tuyn lu thng l 10, 20) .

g. Tc ng do s xo ng t vic bm ht ct v san lp ct

Trc ht xem xt tnh cht l thuyt ca s xo ng nyCc loi tc ng ph thuc vo:

Cc yu t hnh hc nh hnh dng ca a hnh ( di v rng tng i so vi sng bin), su, khong cch n ng b v su gia khu vc khai thc v ng b;

Cc thng s thy lc nh sng, dng chy,...

Cc thng s trm tch (kch c ht, lu tc,...)

Hnh th mi ca y bin sau khi khai thc s tc ng n kiu lan truyn sng v s vn chuyn bn lng. Di cc iu kin mi ny, hnh dng hnh hc ca khu vc khai thc v cc vng ln cn b nh hng: su v s lan truyn sng thay i t cn bng mi. y bin khu vc khai thc c th bng phng hn ti mt s v tr cc b ph thuc vo s bi lng sau khi khai thc trong khi tan b khu vc c th dch chuyn di tc ng ca dng chy chnh. Cc tc ng n ng b c th l kt qu ca s ngn tr vn chuyn bn lng dc b hay l vn chuyn ngang b theo ma (hnh 7 bn tri). N cng l kt qu ca kiu lan truyn sng mi, ch yu l s phn nh ca cc h khai thc (tng chiu cao sng mt trong hai pha ca h, Hnh 7 bn phi), v s bin i ca cc mt ct.

Hnh 3.2. S chn ngang v vung gc vi b ca bn lng

(1) Thay i lan truyn sng

Khi sng ti khu vc khai thc, sng b un theo ng m cc con sng dch chuyn bn trn cc khu vc su nht tng tc v t ti ng b sm hn l khi khng c cc h ct (Hnh 4). Thi gian sm tng i t nh lng bi Migniot v Viguier (1983) i vi b thng v sng nh vo b bnh thng:

Trong :

( : l chiu di sng bn trn h ct

(o : l chiu di sng su tng t nhng khng c h ct.

Cc tc gi bng thc nghim tm ra kt qu phn nh cc nh hng ti s pht trin ca b trong b qua:

Trong :

Lsc l khong cch t h n b

(sc l chiu di trung bnh trn khang cch Lsc (du Gardin et al., 2002).

Cng thc n gin ny c th pht trin nu tnh thm cc tc ng gin tip v cc thng s trm tch.

Hnh 3.3. S chuyn ng tng i ca sng do phn x

ca h ct pha trc

Khi khai thc cc cn ct ngm trong sng b v trc im khai thc (chiu su mc nc cao hn cc cn ct: d) v lun lun b v pha sau (chiu su mc nc trn cc cn ct: d+p), s tng tng i chiu cao sng cc cn ct v b c th tnh ton (Hnh 5). Gi thit rng chiu cao sng ln nht sau khi v Hmax khng vt qu chiu cao sng ti im v (mt cch logic th khng c s tng ca sng sau khi v) v s dng cc chun mc ca Batjies v Jansen, chng ta c:

Hmax = (d vi (=0.75.

T s tng tng i chiu cao sng i vi cn ct :

Cng thc n gin ny c th dng xc lp chiu dy ln nht ca lp ct m chng ta c th khai thc m khng lm tng chiu cao sng so vi trc.

Cc m phng s c s dng kho st cc nh hng tng i ca nhiu thng s n s thay i ca chiu cao sng ti im v i vi s hin din ca cc h hnh ch nht (Amde, 1999; du Gardin et al., 2002). Qu trnh tnh dng tnh tan trong cc m phng ny l s phn hi ca sng. Kt qu cho thy:

Xem xt ba chiu ca h ct hnh ch nht vi mt th tch cho trc, cc yu t c hi l (theo th t gim dn): chiu vung gc vi cc ngn sng, su ca h, chiu song song vi cc ngn sng chim u th. Trong trng hp ng b thng v chiu sng u th xc nh, hnh dng gy t tc hi nht l cc h nng hnh ch nht vi cnh di hn song song vi ngn sng;

S t lan ta ca sng cng l mt yu t xu: cc con sng mt chiu lm tng cc tc ng ca s phn hi;

Khong cch ti b tt nhin l mt yu t nh hng.

Tuy nhin trong cc trng hp phc tp cn phi dng cc phn mm my tnh d on cc nh hng ca khu vc khai thc n s lan truyn sng.

M hnh tnh ton st l ca TS. Nguyn c Tin lp trnh dng tnh ton qu trnh st l, bi lp hm khai thc ct (vi trng hp din tch m khai thc l 1 km2) s c p dng tnh ton cho trng hp m Long Ha IV (nu c th trong phn ph lc)

Phn tch m hnh Hm khai thc - L mt h hnh vung, c li sau khi khai thc ct san lp. Kch thc: cnh (AB,BC ..) di 1000m, b su (ti a) BH = h=4,0m. Mt y phng.(Hnh 1). Mt nghing ca khi hnh nm (mp. A1EHB1) l b mt mi dc ca i st l xung quanh hm khai thc. Gc dc ca mi l ( vi tan(() = AE/AA1. Trng thi - Hon ton b ngp nc (bin). a hnh mt y bin xung quanh hm c coi l bng phng,

St l, bi lng - B qua s bi lng ca ct do sng bin mang t xa n. Gi thit rng qu trnh bi lp hm khai thc ch do