General Report of Dredging Waterway of Corridor No 2 and 3 - Mekong Delta Transport Infrastructure Development Project (MDTIDP)

Mekong Delta Transport Infrastructure Development Project (MDTIDP) Main Waterway Corridors Improvementphase 2 Plus Supervision Of Phase 1+2 General Report of Dredging Waterway of Corridor No 2&3 CHAPTER 3: NATURAL CONDITIONS, PRESENT STATUS AND CONSTRUCTION PLANNING WITHIN THE PROJECT AREA 3.1. ADMINISTRATIVE GEOGRAPHICAL NAMES ALONG THE WATERWAYS CORRIDORS 3.1.1. Geographical names along the two banks of corridor 2 The Corridor 2 channels are located in Ho Chi Minh City, Long An Province, Tien Giang and Dong Thap provinces. The geographical names of wards and communes are listed in the Table 1.1 – appendix 1. 3.1.2. Geographical names along the two banks of corridor 3 The corridor 3 channels are located in Soc Trang province and Bac Lieu province. The geographical names of wards and communes are listed in the table 1.2 – appendix 1. 3.2. HYDROMETEOROLOGY 3.2.1. Meteotological Conditions The documents collected from the Southern Hydrometeorology Centre indicate the main features of hydrometeorology as follows: a. Air temperature The annual average temperature is 27,1 oC; maximum 34,7 oC, minimum 18,6o C. The hottest month is May and the coolest month is January. The temperature value of air does not have big changes (from 26,8oC to 27,2oC). the maximum temperature changes from 34,0oC to 40,0oC and the minimum temperature changes 14,8oC to 19,7oC. there are three periods: + From January to April, the temperature is increasing. The average temperature increases from (25 ÷ 26)oC to (28 ÷ 29)oC. + From May to November, the temperature does not have much change. The average temperature reduces from (28 ÷ 29)oC down to (26 ÷ 27)oC + From November to January next year, The temperature reduces quickly. The average temperature reduces from (26 ÷ 27)oC down (25 ÷ 26)oC. b. Evaporation from ground The annual average evaporation is 1.000 ÷ 1.400 mm, maximum 1.414 mm . In dry season, evaporation reaches from 91.8 ÷ 143.4mm and in rainy season, evaporation reaches from 49.8 ÷ 90.9 mm. c. Sunshine hours over the year In dry season, from November to May, the sunshine hours do not exceed 200 hours per month. The least sunny months are June and September coinciding with the maximum rain events. The average sunshine hours is 2551 hours/per annum. d. Humidity Humidity is closely related to the rain and wind in the area. The month with the highest mean humidity is May (31.1 mb), the lowest mean humidity is January (24.5 mb). The annual average humidity is 28.4 mb. The minimum average relative humidity is 21% (February 1974) and the high average humidity is 78%. e. Rainfalls There are two seasons per year: rainy season and dry season in which the dry season is coincided with the North-eastern monsoon. Page 11 Mekong Delta Transport Infrastructure Development Project (MDTIDP) Main Waterway Corridors Improvementphase 2 Plus Supervision Of Phase 1+2 General Report of Dredging Waterway of Corridor No 2&3 + The rainy season is coincides with the South-western monsoon, the rainfall is accounted for 90% of the year. The total average rainfall varies from from 1.455 to ÷ 2.007 mm. the maximum rainfall of the year is 2.709 mm and the minimum rainfall is 638 mm. During the rainy season, the highest rainfall is in June and October (rainfall of October is higher than June). + During July, the end of August and beginning of September, the rainfall rarely reaches a peak value + During the rainy season, there are normally 90 – 130 rain days. In average, there are 15 rain days per month. + The dry season begins from November or December and prolongs to lasts till April of the subsequent year. f. Wind The project area is located in the tropical monsoon. The dry season is mainly influenced by the Northeastern monsoon and the South-western monsoon. The visibility range is good, reaching 20km (particularly in December, it is likely to reduce to 5 km). There are two seasonal winds: + The dry season begins in November and prolongs to lasts till April with the main Eastern wind direction (normally up to 70%). + The rainy season begins in June and ends in September with the two main western wind and South-western wind directions. The frequency of these two wind directions are accounted for 7080 % + May and October is the transitional period between the aforementioned wind seasons. g. Rainstorm The project area is deemed to be of many rainstorms appearance (Average 243 rainstorm hours per year and 110 rainstorm per year) . The rainstorms usually strike at the beginning of rainy season. During the rainstorm, wind can reach level 7 – 8 (50-74 Km/h) Typhoons in the area appear less. From 1911 to 2009, there have been 10 typhoons striking into the Southern area. The intensity of the typhoon is often low under level 11(103-117 Km/h). The typhoon normally strikes in October and November. 3.2.2. Hydrographical Conditions a. Tide The two corridors are influenced by tide from eastern sea with semidiurnal tide regime, simultaneously be influenced by Mekong river flood, however, the corridor 3 is not significantly influenced. The corridor 2 is influenced by the system of river tide: Sai Gon River, Vam Co River, Tien River. These rivers have mean tide at sea outlet about 3,0 – 3,5 m during the high tide. The highest tide reaches over 4,0 m. + At Tan Chau (220 km from the sea outlet) the average tide is from 5cm (dry season) up to 100cm (rainy season) + At My Tho (50 km from the sea outlet ), the highest tide/tidal range is 3.50 m and low tide is 1.5m. + The mean of highest tidal in Binh Thuan is 1.80 – 1.90 m. + Average value of the amplitude of the largest tides in the My Thuan During the flood season, the areas far away from Tien river are not influenced by tide. Page 12 Mekong Delta Transport Infrastructure Development Project (MDTIDP) Main Waterway Corridors Improvementphase 2 Plus Supervision Of Phase 1+2 General Report of Dredging Waterway of Corridor No 2&3 Tabe 3-1: The specific water levels by the hydrographical stations near the corridor 2 channel Ten Years Average YEAR Station Features 2000 2002 2003 2004 2005 2006 2007 2008 2009 in cm Average 6 3 1 5 0 -1 4 4 8 7 4 Max 142 137 150 158 141 139 147 148 152 157 158 Min -237 -244 -237 -239 -267 -270 -265 -258 -260 -258 -270 Amplitude 379 381 387 397 408 409 412 406 412 415 401 Average 22 19 16 14 12 9 14 14 21 18 16 Max 138 140 145 136 135 140 137 140 144 137 145 Min -145 -164 -157 -158 -168 -169 -173 -170 -160 -158 -173 Amplitude 283 304 302 294 303 309 310 310 304 295 301 Average 30 26 21 16 15 15 19 18 24 22 21 Max 166 163 171 140 144 145 144 143 141 143 171 Min -156 -174 -162 -178 -176 -183 -172 -167 -158 -162 -183 Amplitude 322 337 333 318 320 328 316 310 299 305 319 Average 97 87 79 58 59 65 62 59 68 65 70 Max 266 247 249 138 175 188 157 150 145 141 266 Min -25 -21 -34 -24 -21 -39 -21 -25 -13 -33 -39 Amplitude 291 268 283 162 196 227 178 175 158 174 211 Average 37 33 29 23 23 24 26 25 32 30 28 Max 171 158 161 118 129 131 123 123 124 128 171 Min -121 -125 -135 -120 -136 -122 -128 -117 -107 -110 -136 Amplitude 292 283 296 238 265 253 251 240 231 238 259 Average Nha Be 2001 65 63 56 45 45 48 49 48 55 51 53 Max 199 193 194 129 150 154 140 139 136 138 199 Min -94 -82 -85 -80 -88 -98 -81 -83 -79 -103 -103 Amplitude 293 275 279 209 238 252 221 222 215 241 245 Ben Luc Tan An Kien Binh Long Dinh Long Dinh Cai Lay Page 13 Mekong Delta Transport Infrastructure Development Project (MDTIDP) Main Waterway Corridors Improvementphase 2 Plus Supervision Of Phase 1+2 General Report of Dredging Waterway of Corridor No 2&3 The Corridor 3 is influenced by semi-diurnal regime from Eastern Sea. from outlets such Tran De river, My Thanh river, Ganh Hao river and through channels : Cai Cung; Nha Mat etc,. The tide is higher at the beginning of Tran De river than the end of channel which is influenced by the tide of Ganh Hao and through Cai Cung canal; During the flood season, the areas far away from Tien river are not influenced by tide. Table 3-2: The specific water levels by the hydrographical stations near the Corridor 3 channel: Ten Years Average YEAR Station Features 2000 2001 2002 2003 Average in cm 20 19 15 14 Max in cm 180 198 205 Min in cm -175 -188 Amplitude in cm 355 Average in cm 2004 2005 2006 2007 2008 2009 in cm 14 13 17 15 22 21 17 194 195 200 200 201 196 193 205 -178 -197 -196 -195 -192 -195 -186 -178 -197 386 383 391 391 395 392 396 382 371 384 1 1 -1 0 -1 1 6 7 Max in cm 186 198 201 193 186 205 205 200 205 Min in cm -206 -220 -211 -205 -215 -213 -215 -204 -220 Amplitude in cm 392 418 412 398 401 418 420 404 408 Đai Ngai My Thanh 2 Average in cm 30 30 30 Max in cm 220 218 220 Min in cm -198 -197 -198 Amplitude in cm 418 415 417 Tran Đe Average in cm 30 29 25 29 25 24 30 32 35 33 29 Max in cm 85 72 67 69 68 72 71 78 75 73 85 Min in cm -42 -30 -25 -25 -25 -30 -29 -20 -23 -23 -42 Amplitude in cm 127 102 92 94 93 102 100 98 98 96 100 Ca Mau Page 14 Mekong Delta Transport Infrastructure Development Project (MDTIDP) Main Waterway Corridors Improvementphase 2 Plus Supervision Of Phase 1+2 General Report of Dredging Waterway of Corridor No 2&3 b. Seasonal flood The flood season usually begins from the end of June and prolongs to lasts till end December, divided into three distinct phases. In phase 1, from July to August, the flood water runs into canals and creeks in Dong Thap Muoi and Long Xuyen Quadrangular. Flood peak happens in phase 2 when the water level of Tien river in Tan Chau is higher than 4.2 m, and water levels of Hau river in Chau Doc is higher than 3.5 m. During phase 3, the water level is goes down gradually until end December. Water is rising gradually at a rate of 10 to 15 cm per day. The flood water is sluggish at a rate of 60 to 70 Km per day The corridor 2 is directly influenced by flood from Binh Chanh (Cho Dem canal) down the end of Kien Giang channel (Tam Ngan canal). The flood areas of Mekong River Delta The corridor 3 is not dominated by floods because it is far from the flood areas. c. Water Levels Due to the influence of both tides and floods, the water level on the two corridors change in a complex manner, especially from section of Cho Dem canal to the end of corridor. In the dimension from Rach Chanh to Dong Thap Muoi, there are many anti-salt works, especially Rach Chanh, this makes water level on the corridor channel change very complicated. In order to define the water level for the purpose of transport service, the survey has been done with 21 water survey stations on the two corridors during 16 continuous days. In there, the observations of water levels at an upstream and downstream section has been done on Chanh Creek Gate, and implemented during the dry season (May 2010) when Rach Chanh Gate was closed to prevent salinity instruction. Overview of the locations where water levels have been observed and measured along the corridor 2 during 2010 by hong hung engineers. : Locations of water level observations.  : Locations of hydrometric survey measurements. Page 15 Mekong Delta Transport Infrastructure Development Project (MDTIDP) Main Waterway Corridors Improvementphase 2 Plus Supervision Of Phase 1+2 General Report of Dredging Waterway of Corridor No 2&3 In combination with the hydrometric document at the water level observations, the correlation of the observation. The water level corresponding to the hourly frequency of 10 years observation on corridor 2 as following table: TV10 141 127 141 125 148 122 143 118 140 121 142 110 130 110 131 81 131 77 165 82 185 85 203 15 118 133 120 133 117 140 114 135 110 132 113 135 103 124 103 124 73 124 74 150 78 169 80 183 20 112 124 112 125 110 131 107 127 104 124 107 128 98 118 97 118 77 118 71 138 75 154 77 167 25 105 117 105 118 103 122 100 120 97 117 101 122 93 112 90 112 75 112 69 130 72 146 74 158 30 97 109 98 109 96 115 94 112 91 109 94 115 88 105 85 105 73 105 67 125 70 140 71 151 35 89 100 91 101 89 107 88 105 85 102 87 108 82 100 78 98 72 98 65 120 68 133 68 143 40 81 91 82 93 80 99 80 97 77 95 80 101 75 94 72 92 70 92 64 115 66 127 66 137 45 72 83 74 85 71 90 71 89 69 87 73 94 68 88 65 85 68 85 62 110 64 121 64 130 50 62 75 64 76 62 80 62 80 60 77 64 86 61 82 57 78 66 78 61 106 62 116 62 124 55 51 63 53 65 51 70 52 71 50 69 55 79 53 75 48 71 64 71 59 102 60 111 60 118 60 40 52 43 53 38 60 40 60 39 60 44 71 44 68 38 63 63 63 57 98 58 106 58 113 65 27 38 30 40 25 50 29 50 26 49 32 62 34 60 27 55 61 55 55 94 56 102 55 107 70 12 22 15 25 12 35 15 37 14 36 20 53 23 50 14 44 58 44 53 90 58 97 52 102 75 -6 3 -2 5 -3 20 1 24 0 22 5 40 11 40 1 32 56 32 51 85 51 93 48 96 80 -24 -17 -20 -13 -20 6 -14 10 -15 8 -9 27 -2 30 -14 21 53 21 48 81 48 87 45 90 85 -46 -40 -40 -35 -36 -10 -29 -5 -30 -7 -24 13 -15 17 -28 7 50 7 45 77 44 80 41 84 90 -70 -65 -45 -60 -55 -30 -48 -21 -48 -23 -40 -4 -29 3 -43 -8 45 -8 41 72 39 75 35 78 95 -100 -93 -95 -88 -78 -53 -68 -45 -68 -46 -60 -25 -45 -17 -61 -30 40 -30 35 66 33 70 28 71 98 -130 -120 -120 -113 -99 -80 -88 -70 -87 -70 -79 -50 -62 -35 -80 -52 33 -65 32 62 26 64 20 64 100 -200 -190 -180 -150 -140 -140 -130 -140 -130 -120 -100 -110 -90 -120 -110 00 -110 0 40 -10 40 -20 40 Km Km0+00 Km04+00 Km10+00 Km18+00 Km32+00 Km37+00 Km47+00 Km51+00 Km51+300 Km62+00 Km73+00 dry 126 dry 10 dry 136 150 136 160 130 153 128 150 129 152 118 138 118 140 88 140 82 190 88 212 91 240 dry 150 dry 135 dry 5 dry 150 161 152 174 146 169 143 165 145 168 130 153 132 157 100 157 92 210 100 240 106 270 dry 162 dry 150 dry 1 -180 flood TV9 flood TV8 flood Rach Chanh flood TV7 flood TV6 flood TV5 flood Flood (main tide) Dry (main tide) Ben Luc flood TV4 flood TV3 flood TV2 flood TV1 dry frequ ency (%) Km81+00 Page 16