Study of some characteristics of the cau river basin in bac kan province

THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY NGUYEN THI LAN TOPIC TITTLE: STUDY OF SOME CHARACTERISTICS OF THE CAU RIVER BASIN IN BAC KAN PROVINCE BACHELOR THESIS Study Mode : Full-time Major : Environmental Science and Management Faculty : International Training and Development Center Batch : 2011-2015 Instructor : Dr Pham Van Dien Thai Nguyen, September 2015 DOCUMENTATION PAGE WITH ABSTRACT Thai Nguyen University of Agriculture and Forestry Degree Program Bachelor of environmental Science and Management Student name Nguyen Thi Lan Student ID DTN1153150048 STUDY OF SOME CHARACTERISTICS OF THE CAU Thesis Tittle Supervisor(s) RIVER BASIN IN BAC KAN PROVINCE Prof Dr Pham Van Dien, Viet Nam Forestry University (VFU), Viet Nam Abstract: The development of the country towards industrialization - modernization, environmental problems have risen including the water environment problems in the river basin Therefore, the exploitation of the river, beyond the knowledge of the network of hydrological and geographical characteristics of its forms This study conducted in the stretch of the Cau river running through Bac Kan province Cau river basin in Bac Kan province includes Bac Kan town, Cho Don district (Ra Ban, Dong Vien and Phuong Vien commune), Bach Thong district and Cho Moi district Studying some characteristics such as topography, landforms, climate features, and hydrological and vegetation characteristics The Cau river basin in Bac Kan province in the high mountain regions, the terrain is quite complex and special; steep slope and altitude, and the upstream of many rivers, so the concentrating flow in the rainy season is very fast The climate there is a clear seasonal difference Winter is low temperatures, little rain and under the influence of the northeast monsoon Summer has high temperatures with lots of rain so rainfall generated floods in highly concentrated areas, frequency of rain that created i flooding during the months of fairly uniform, concentrated mainly in the June, July and December Study of some characteristics of the Cau river basin will be addressed to assess the advantages and difficulty of watershed from which resources most effectively, as well as the protection and development of Cau river basin in a sustainable manner So study of some characteristics of the Cau river basin such as topographical land use, vegetation cover, hydrological and climate characteristics will be addressed to assess the advantages and difficulty of watershed from which resources most effectively, as well as the protection and development of Cau river basin in a sustainable manner Keywords Cau river basin, topographical land use, vegetation cover, hydrological and climate characteristics Number of papers 66 pages Date of submission: 9/30/2015 Signature of supervisor Pham Van Dien ii ACKNOWLEDGMENT On the occasion of the thesis completion, I would like to express my appreciation to the Department of Natural Resources and Environment, Department of flood protection, Department of Agriculture and Rural Development in Bac Kan Province for support and kind provision of necessary information concerning this study In particular, I would like to express my gratitude to Dr Pham Van Dien who guided, instructed, coached me in the course as well as in implementation of this thesis Due to the time frame and my ability and experiences are limited, some shortcomings of the thesis should not be avoided I look forward to the comments by the teachers for improving my graduation thesis I would like to sincerely thank you! Thai Nguyen, Wednesday, 31 August, 2015 Student Lan Nguyen Thi Lan iii TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES INTRODUCTION CHAPTER 1: LITERATURE REVIEW 1.1 Concept of river basin 1.2 The characteristics of a river basin 1.2.1 The geometrical characteristics of the river basin 1.2.2 Characteristics denote the flow 1.2.3 Climate factors 1.2.3 Buffer factor 1.3 The characteristic elements of river basin in Vietnam 10 1.3.1 The climate factors 10 1.3.2 Soils and lava 11 1.3.3 Topographic 11 1.3.4 Forest 12 CHAPTER 2: OBJECTIVES, OBJECTS AND LIMITATION, THE CONTENT AND RESEARCH METHODS 13 2.1 Objective 13 2.2 Scope of research 13 2.3 Research Content 13 2.4 Research Methods 13 CHAPTER 3: RESULTS AND DISCUSSION 15 3.1 Overview of the Cau river basin in Bac Kan Province 15 3.1.1 Natural characteristics 15 3.1.2 Characteristics of economy and society 18 iv 3.2 Topographical, geomorphology features of the basin 20 3.2.1 The topographical zones 21 3.2.2 The slope of the terrain 22 3.2.3 The type of terrain 25 3.3 Geological characteristic 26 3.3.1 Geological structure 27 3.3.2 Features of stratigraphy 28 3.3.3 The intrusive magma rock 30 3.3.4 Overview of fault system 31 3.4 haracteristics of vegetation layer and coating plant 32 3.4.1 Vegetation Features 32 3.4.2 The major forest types 34 3.4.3 The percentage of forest cover 35 3.4.4 Assess the advantages and difficulties 37 3.5 Climate Characteristics 38 3.5.2 Climatic feature 39 3.6 Hydrological characteristics 48 3.6.1 The main characteristic of the rivers and streams of Cau the river basin 48 3.6.2 Hydrological station network 49 3.6.3 The characteristics of hydrological flow 49 3.6.4 Assess the advantages and disadvantages of water resources 54 CONCLUSIONS, RECOMMENDATIONSU 55 Conclusion 56 Recommendation 57 REFERENCES 58 v LIST OF TABLES Table 3.1 Decentralization of the slope of the Cau river basin in Bac Kan province 22 Table 3.2 Forest status in district of the Cau river basin in Bac Kan province in 2014 32 Table 3.3 The percentage of forest cover through the years from 2009 to 2014 35 Table 3.4 The percentage of forest cover in the districts and towns of Cau river basin 36 Table 3.5 A meteorological station and rainfall measuring station in Bac Kan province 38 Table 3.6 Air temperature characteristics 40 Table 3.7 Relative humidity of the air 41 Table 3.8 Total average sunshine hours in a month and year 41 Table 3.9 The average evaporation in the month and year piche tube 42 Table 3.10 Average wind speed of month and year 43 Table 3.11 The average total rainfall in the month and year 44 Table 3:12 Distributor average rainfall for the month and year 45 Table 3.13 yearly rainfall frequency 45 Table 3:14 The ratio of year rainfall is seasonal distribution 45 Table 3:15 statistically the highest rainfall of periods 1,3,5,7 days 46 Table 3:16 m coefficient calculated on the average for positions rainfall stations 47 Table 3:17 Percentage (%) of rainfall that generated floods appear during the rainy season in some regional stations 47 Table 3.18 hydrological station network, time factors and monitoring 49 Table 3:19 The annual average flow is measured on the stations 50 Table 3:20 Flow in the dry season in Cau river basin in Bac Kan province 51 Table 3.21 the frequency of runoff courses in some river basins of Cau stations in Bac Kan province 51 Table 3.22 The frequency of flood flow at several stations in Cau river basin 52 Table 3.23 Average turbidity in monitoring period 53 LIST OF FIGURES Figure 3.1 Map of Cau river basin in Bac Kan province 16 Figure 3.2 The percentage of forest cover in the districts and towns of Cau river basin in Bac Kan province 35 INTRODUCTION Research rationale Currently, along with the development of the country towards industrialization modernization, environmental problems have risen including the water environment problems in the river basin Therefore, the exploitation of the river, beyond the knowledge of the network of hydrological and geographical characteristics of its forms, must also have the full understanding of the geographical factors affecting the flow, formation and evolution of river basin flow On that basis, we understand in detail the nature of the physical and hydrological characteristics Cau river basin is one of the largest river basins in the country This is the most important watershed in the Thai Binh river system that the area is 6,030 km2 with main flow is Cau river of 288.5 km long which originates from the Van On mountains at an altitude of 1.175m and flowing into the Thai Binh river at Pha Lai district Cau river basin has 26 tributaries at levels I and 41 tributaries at levels II with a total length of 671km and 643 km, respectively, and hundreds of kilometers of branches at levels III, IV and shorter ones, which its length is under 10km Topic "Study of some characteristics of the Cau river basin", such as topographical land use, vegetation cover, hydrological and climate characteristics will be addressed to assess the advantages and difficulty of watershed from which resources most effectively, as well as the protection and development of Cau river basin in a sustainable manner CHAPTER LITERATURE REVIEW 1.1 Concept of river basin River basin is the water area that water (including surface water and groundwater) will flow into the river The river is limited by watershed (watershed line) of the basin There are two kinds of watershed: the watershed line of surface and groundwater - The source of the river is where the beginning of the river The big rivers are often rooted in the high mountains, and dense forest In which having many ravines, crisscrossing small streams, and water flows all the year Sometimes the river originates from groundwater or a large lake - The upper course of a river is often high areas with steep terrain, and is complicated separation This is where the beginning of rivers, and surface often covered by forests which is like the "green water storage " that have a role in flow condition, reducing flows of flood peak and increase dry season flow for downstream - The middle course of a river is often mountainous or highland areas where terrain is low, and is the intermediate zone which transfer water into a downstream area In the middle course, the rivers often have smaller slopes, riverbeds begin to expand out, and riverbed has many fine sandy The riverside often at risk of being inundated that forming dumps containing flood - Lower course of a river is the lowest zone of the river basin that mostly perennial alluvial can create the broad plains Generally, when the river flows to the river downstream, river section is expanded, and often divided into several branches to flow into the sea River in the lower course area usually has a small slope, and mud Rainfall in the short term: Data measurements show that the highest rainfall in 24 hours in all places are reached 200 mm, many places range from 300 to over 400 mm Most rain intensity was observed day in Cho Don station 439.3 mm; Na Ri station is 445.2 mm, in Bac Kan station is 304.9 mm The greatest rainfall in periods 1, 3, 5, continuous days that have fairly large coefficient of variation (Cv) achieved from 0.29 to 0.65 The statistical parameters, design rainfall periods 1, 3, 5, continuous days at the most monitoring stations are shown in the following table: Table 3:15 statistically the highest rainfall of periods 1,3,5,7 days stations Bac Kan Cho Don Cho Moi Periods of days XTb X1max X3max X5max X7max X1max X3max X5max X7max X1max X3max X5max X7max 110,2 160,4 188,4 212,9 130,2 189,6 224,2 257,9 124,7 184,0 218,3 245,6 Cv (coefficient of variation) 0,436 0,473 0,418 0,383 0,457 0,38 0,341 0,335 0,371 0,369 0,38 0,359 Xp% (mm) Cs(coefficient of skewers) 0,5% 1% 2% 5% 10% 1,746 2,185 1,931 1,92 3,077 1,698 1,359 1,122 0,574 0,696 0,788 0,46 309,5 500,2 525,8 561,7 430,2 485,6 516,0 570,6 268,8 403,2 493,4 511,2 277,7 441,5 470,1 504,1 371,2 438,8 472,9 526,8 251,5 375,9 458,1 480,5 246,0 384,1 415,0 447,3 315,0 392,2 429,5 482,3 233,3 347,4 421,6 448,0 204,4 310,4 343,4 373,3 245,8 330,7 371,0 421,5 207,5 307,3 370,6 401,4 173,0 256,2 289,8 318,0 197,8 284,0 325,6 373,3 186,0 274,3 329,0 362,1 (Source :Department of Agriculture and Rural Development in Bac Kan Province) Coefficient decreased rainfall: The result of calculation shows that rainfall is designed days corresponding to the frequency of 10% in the study area could reach 223 mm to 325 mm Rainfall largest day normally associated with precipitation 3, 5, days a rain greatest via expression: XT = X1x T m 46 Where: XT: Precipitation of T biggest day during rain X1: Precipitation of biggest day during the corresponding rain T: Time of rain calculated in days From the measured data, determine the coefficient m in time T at some measuring stations are averaged as follows: Table 3:16 m coefficient calculated on the average for positions rainfall stations stations Bac Kan Cho Don Cho Moi T = days 0,338 0,352 0,351 T = days 0,339 0,351 0,342 T = days 0,349 0,362 0,343 (Source: Department of flood prevention in Bac Kan province) Rainfall that creates flooding in the study area is relatively concentrated Number of times of rain created flooding occurs during the months of flooding are fairly uniform Heavy rains which create floods focuses primarily on the June, July and May 8, the frequency of occurrence of heavy rains that create floods in three months was around 61 to 81% of rains create floods during the year According to statistics the largest rainfall occurs the year in July is often associated with periods of thunderstorms and storm activity, so the research on the interior, the high mountains were stopped, so basin mainly affected by thunderstorms and hurricanes hit the Gulf of Tonkin, but not affected directly Table 3:17 Percentage (%) of rainfall that generated floods appear during the rainy season in some regional stations unit:% stations The wet months 10 11 Bac Kan 0,00 12,96 22,22 27,78 22,22 11,11 1,85 1,85 Cho Don 2,04 4,08 24,49 34,69 22,45 8,16 4,08 0,00 0,00 20,41 12,24 26,53 22,45 14,29 2,04 2,04 Thac Rieng Cho Moi 4,08 10,20 22,45 18,37 28,57 6,12 8,16 2,04 47 3.6 Hydrological characteristics 3.6.1 The main characteristic of the rivers and streams of Cau the river basin In general, flow system of Cau river basin in Bac Kan province with the characteristics of steep river, with many waterfalls and rapids, riverbed is narrow, Vshaped wall, very strong erosion and transportation large quantities of material materials in the flood season The flow fluctuates sharply during the year The rainy season transfer 70-80% of water, or cause flooding, especially unexpected flood, flash flood, heavy damage to crops, property and human life Conversely, in winter, very little water streams, almost exhausted, the river shrinks affect agriculture, forestry and activities of people in the region Because the characteristics of mountainous terrain is high with large arc shape, so the Cau river in Bac Kan province is the source of many rivers, streams, quite dense networks and flows in different directions In addition to the Cau river, in the basin there are about 30 large and small streams flow into the river while the large river branches have tens of kilometers in length, and the main branch as follows: - Khuoi Bun stream derived from PhjaTang mountain system (977m) of Duong Phong commune flows into Cau River in the south of Ban Bun - Đon Phong stream from the mountains of the western of Đon Phong commune, entering to Cau river the territory of the town of Bac Kan town - Nam Cat stream streams from the mountains the northern of Don Phong commune also flows Bac Kan town into the Cau river After flowing through the My Thanh commune, Bach Thong district, Cau river moved towards the northeast - southwest to the territory of Cho Moi district, in Cho Moi, Cau river received water from multiple streams in both the west and east + The West, there have Tat Meo stream, Rieng stream, Hom stream and Cua Khe stream + The East with clefts Khe Thuong stream, Pe Pau stream, Tai stream, Nhi Ca streams, Na Lang streams 48 After running all the territory Na Lang village, Quang Chu commune, Cho Moi district, Cau River flows into Thai Nguyen province With these characteristics in terms of flow and flow slope, hydrological regime in the region will be a major influence on the basin surface erosion, which make rivers and streams often have relatively high amount of mud sand Especially Cau River, Buoi waterfall (Cho Moi district) with medium sand is 233 g/m3, the moving sand of 12.1 kg/s and total sediment 380 million m3/year Cau River is very good that contains about 3.0% Ca and P2O5, N ratio is approximately 0.77 to 0.88% 3.6.2 Hydrological station network Hydrological monitoring the situation in the study area is generally lacking, Cau River basin hydrological stations only have two that includes Cau Pha and Thac Rieng By considering analytical models used Nam model to calculate stretching flow data chain from the rainy day for the station and the small basin Table 3.18 hydrological station network, time factors and monitoring measuring stations Cau Pha Thac Rieng site Monitoring element Flv Start / East North river (km2) Finish particle Water H Q sediment liquey Longitude latitude Composition temperature 1960105049' 22008' Cầu 363 + 1981 105052' 22004' Cầu 712 1960 + + + + + + (Source: Department of flood prevention in Bac Kan province) 3.6.3 The characteristics of hydrological flow a The flow of the year: By calculating the average flow in the years (Table 2.16) shows: The depth of the annual flow of Cau river basin, only counted Thac Rieng in the period 1990 to 2000 is 770 mm/year corresponds with the flow of the year is 24.3 l/s, km2 The average of the period 2000 to 2014, the average flow increases respectively 775 mm/year At Dau Dang station, on the Nang River, the depth of the flow only reached 708 mm/year in the period 49 from 1990 to 2000 and this value increased to 723 mm /year in time from the year 2000 to 2014 This shows that the annual flow distribution across the province is uneven, variable flow from the northwest of the province (The Nang River) ascending to the central part of the province (Cau River) Table 3:19 The annual average flow is measured on the stations unit: m3/s station Flv months s km2 Đau Đang 189 15, 13, (19900 6 2000) Đau Đang 189 12, 10, (Nam) (20002014) Thac 5,3 4,9 Rieng 712 (19901 2000) Thac Rieng 6.6 5.5 (Nam) 712 (20002014) 10 11 12 yea r 13, 16, 30, 65, 83, 102, 67, 39, 29, 19, 41, 14, 25, 46, 74, 92, 81,1 60, 41, 27, 17, 42, 5,1 8,4 16, 28, 34, 41,5 29, 16, 10, 6,5 17, 5.8 8,7 15, 27, 33, 38,4 29, 19, 13, 8,4 17, (Source: Department of Agriculture and Rural Development in Bac Kan Province) Notes: Thac Rieng station and Dau Dang station that using the Mike model lasted until 2014 b The flow in the dry season: Through calculating the frequency of runoff courses in Table 4:19 shows that most small runoff courses below the average flow in the dry months, the corresponding frequency is 85-90% of the average flow during dry months 50 In general, runoff courses in Cau river basin in Bac Kan province lasts from November to May of the following year According to monitoring data show that the total volume of flow in dry season reaches only 25% - 30% of the total annual flow volume and flow in dry season usually falls in February, March Best model of the average runoff courses ranges from 2.3 to 3.1 l/s km2 Table 3:20 Flow in the dry season in Cau river basin in Bac Kan province Unit: m3/s Qdriest Qtb Flv stations (km2) Periods (m3/s) M0average (l/s,km2) Mdriest month month(l/s,km ) (m /s) Đau Đang 1890 56-76 19,5 10,3 9,32 2,3 Thac Rieng 712 60-81 7,91 11,1 3,23 3,1 (Source: Department of Agriculture and Rural Development in Bac Kan Province) Table 3.21 the frequency of runoff courses in some river basins of Cau stations in Bac Kan province Qp Đau Đang station (m3/s) Đặc trưng Q average driest month Q average reason driest Qp Thac Rieng station (m3/s) P50% P75% P85% P50% P75% P85% 11,7 10,2 9,4 4,21 3,68 3,43 18,6 16,1 15,1 7,53 6,17 5,65 (Source: Department of Agriculture and Rural Development in Bac Kan Province) c Flood season flow: Based on the results calculated on the average flow for many years at and Dau Dang station and Thac Rieng station showed that flood season of Cau river basin began in June and ended in December The amount of water in flood season accounts for 80-85% of total annual water volume Large floods often occur in July, and May The largest flow was observed at Dau Dang station is 942 m3/s corresponding to the flood peak of 500 l/s.km2 At the Thac 51 Rieng station has observed flood flow is 873 m3/s corresponding to 1.226 l/s.km2 The average flow during floods at Thac Rieng station is 30,1 m3/s, corresponding to 42,2 l/s,km2, at Dau Dang station is 71,7 m3/s, corresponding to 37,9 l/s,km2 Overall, the floods in Cau River in Bac Kan province is not violent because of the intensity of that rain caused small floods But the Nang river upstream (Nam Cuong commune) because the river has steep slopes, rainfall intensity is greater so frequent flash floods occurs in the area On the other hand sections of downstream are narrow, so flooding condition frequently occurs For example, on 17/ 08/2003 in Cho Don district with heavy rain, causing major flooding in the Nam Cuong River However door exists flood drainage into Ba Be lake is buried that should have caused flooding at eight villages, on the lower region of Nam Cuong commune On 07.17.2006 after heavy rains in upstream that extends flooding caused landslides routes from Bac Kan town to Cho Don Flooding regularly occurs causing damage each year in Bac Kan province up to tens of billion Through calculations of the frequency of floods shows that the flood occurrence at Thac Rieng station dated 18/08/1971 corresponding to the frequency of P = At Dau Dang station, floods is in May 8/1971 with Qmax = 942 m3/s, respectively frequency P = 1.5% Table 3.22 The frequency of flood flow at several stations in Cau river basin Unit: m3/s station Cv Cs Thac Rieng 0.50 1.00 Đau Đang 2.14 0.61 QP% (m3/s) Qtb m3/s Calculation 10 Periods 1.127 868 747 2000-2008 1.024 696 560 2009 - 2014 0,1 0,5 448 1.474 1.234 316 1.522 1.171 52 (Source: Department of Agriculture and Rural Development in Bac Kan Province) d Solid flow The amount of sediment in the river has a huge influence on economic activity in the river, to use and build water reservoirs, water intake channels; the life of this construction depends in large part on the level sediment deposition Turbidity sediment is a significant change in quantities, depending on many different factors such as rainfall intensity, basin topography slope, vegetative cover, structural geology and soils of the watershed Sediment turbidity has very large fluctuations during the flood season; the dry season is also changing rapidly and even is Thus the measurements only reflect the relative nature, instantaneous The annual average value is only partly reflected the nature wash surface away of river basin between different geographical areas However, in the same geographical conditions and climate of the same river basin, the average turbidity values during the observation are regarded as approximate In the document measurement conditions are meager here, but refers to the average turbidity was measured on a number of routes in the river Bac Kan province and adjacent areas selected for documentation than calculated Table 3.23 Average turbidity in monitoring period Months (g/m3) station year Thac Rieng Đau 166 488 466 303 312 182 81,2 72,3 13,9 268 20,2 17,8 37,3 38,2 129 243 237 244 104 45,7 31,2 13,8 153 9,34 8,16 10,1 10 11 12 53 Đang (Source: Department of Agriculture and Rural Development in Bac Kan Province) 3.6.4 Assess the advantages and disadvantages of water resources - Advantage Potential for water resources in the river basin in the province of Bac Cau is generally plentiful because there is large rainfall and tends to increase gradually from south to north Annual rainfall is from 1,250 to 1,550 mm The flow of variation is from 10 to 70 l / s.km2 Flood season from June to September accounts for 70-75% of the total annual flow, remaining dry months accounted for only 25-30% of annual flow - The total annual flow is around 3.4 billion m3 Part of Cau river basin has a total annual flow of 961 million m3 - Natural conditions and climate of the Cau river basin is also quite suitable for developing a variety of crops, such as industrial plants, fruit, specialty crops, medicinal plants and forest regeneration - Disadvantages Cau river basin generally less affected by the storm, but they often appear thunderstorms, hail in summer and frost in winter These are adverse weather phenomena in the life of people and agricultural production - The uneven distribution of rainfall and flows in the province has caused considerable difficulties for economic development, agricultural production, especially in the dry season - Surface water of Cau river basin much, but by complex terrain conditions so the possibility to build irrigation works to harness water resources service of production and daily life faced many difficulties 54 - The evaluation of groundwater flow reserve, as well as underground water movement because no adequate assessment survey, should the problem of exploitation and use of groundwater resources in Bac Kan province is very much limited 55 CONCLUSIONS, RECOMMENDATIONS Conclusion The Cau river basin in Bac Kan province in the high mountain regions, the terrain is quite complex and special; steep slope and altitude, and the upstream of many rivers, so the concentrating flow in the rainy season is very fast, thus, the protection of headwater forests has very important implications for production and to people's lives in the province in particular and the region in general Besides, the land is steep, dominated with large rainfall and seasonal concentration leads to soil erosion, landslides is strongest along the transport system to land degradation Lowland valleys (average altitude of - 400m) are resided by Kinh, Thai, Tay, and Nung, hence, the farming methods of people living in this height usually cultivated rice and combined upland fields In which rice cultivation using fertilizers and plant protection drugs increases the risks of soil contamination at low levels The climate there is a clear seasonal difference Winter is low temperatures, little rain and under the influence of the northeast monsoon Summer has high temperatures with lots of rain so rainfall generated floods in highly concentrated areas, frequency of rain that created flooding during the months of fairly uniform, concentrated mainly in the June, July and December Heavy rains, prolonged with steep terrain are strongly divided as the main factor causing erosion, floods and landslides in the province River systems are often short and steep In the rainy season, large water flow is causing floods During the dry season, the river bed is dry, narrow riverbed at downstream causing inundation affecting life, production and people's living environment 56 Surface water sources of Cau river basins a lot, but due to the complex terrain conditions so the possibility to build irrigation works to harness water resources in service of production activities that face many difficulties The watershed in Pac Nam, Ngan Son, Cho Don District is strongly eroded and have less ability to regulate the flow tends to increase flooding and decrease flow in the dry season, the deposition of sediment cause sedimentation reservoirs and canals Recommendation - Increase investment in the development of resources for science and technology in order to facilitate further research on geographical factors of the Cau River in Bac Kan province; access to new knowledge makes review price, given the correctly predicted data about of the basin is to be managed sustainably - River basin planning reasonably is an easy job for assessment of the advantages and disadvantages of the basin - Due to the ecological conditions, hydrological and socioeconomic changes, the watershed, habitat and wholeness of the river should be assessed for each section of the river, especially in those segments right with the research position, as well as the residential area along the river - Establishing a relationship between flow and water levels in the research location will help more and the ecological and social impacts because the flow regime changes were caused - Since the Cau river basin has a close relationship with the river systems, the relationship between upstream - downstream ecosystems and the entire system should be considered as a key component in the work reviews later 57 - The link between floods of different magnitude with additional processes, changing groundwater should be examined and clarified - Continued support for the development process of the project management unit of the Cau River became managing authority the Cau river basin, technical assistance and financing for the continued construction of the agenda of the ecosystem livelihoods that have used methods of assessment of environmental flows as a management tool - Promote research in informatics applications: such as remote sensing, GIS to accurately predict the characteristics of the terrain and Cau river flows, which can make precautionary measures and settle in time - Strengthen education and advocacy to raise awareness for people living along the Cau river basins especially on hygiene and environmental protection of the basin 58 REFERENCES Bac Kan Provincial People's Committee (2006), General report overall planning of socioeconomic development in Bac Kan province until 2020, Bac Kan Bac Kan provincial Department of Statistics (2013), Bac Kan Statistical Yearbook 2013, Bac Kan Bac Kan provincial Department of Statistics (2014), Bac Kan Statistical Yearbook 2014, Bac Kan Dien, M.T., Tam, M.T., Khanh,L.D., Huu N.N., (2014), The characteristics of the Red river terrain and flow Retrieved from http://tailieu.vn/doc/tieu-luan-thuy-van-moi-truongcac-dac-trung-ve-dia-hinh-va-dong-chay-song-hong-1682590.html Department of Natural Resources and Environment (2006), National Environmental Report 2006: The status of the the water environment of river basins: Cau, Nhue - Day, and Dong Nai river system, Ha Noi Department of Natural Resources and Environment, Bac Kan province (2014), Environmental Status Report of Bac Kan province 2011 - 2014, Bac Kan Characteristics of river hydrology (n.d.) Retrieved from http://www.dostbinhdinh.org.vn/diachibd/tndchc/P1_chuong_5.htm Klibasev, K.P., & Goroskov, I.F., (1975), Hydrological Calculation Science-technology publisher, Ha Noi, 1975 Philip B Bedient Wayne C Huber Hydrology and Floodplain Analysis, Addison-Wesley Co., USA, 1992ISBN 0-201-51711-651711 Ngan, N.T., (2009) Application of geographic information system to classify the sub-basin of the Dong Nai river basin Retrieved from http://doc.edu.vn/tai-lieu/de-tai-ung-dung-hethong-thong-tin-dia-ly-de-phan-loai-cac-tieu-luu-vuc-trong-luu-vuc-song-dong-nai36023/ Ray K, Linsley, Jr., Max A Kohler, Joseph L H., (1988), Paulhus Hydrology for Engineers, McGraw_Hill Book Co., ISBN 971-11-0675-2 59 Tuan, L.A., (2008), Environmental hydrology Retrieved from http://www.leanhtuan.com/pdf/GT_ThuyVanMoiTruong.pdf The Red - Thai Binh river basin and system (2009) Retrieved from http://www.vncold.vn/Web/Content.aspx?distid=1862 The Circular No 25/2009 / TT-BNN dated 05/5/2009 of the Minister of Agriculture and Rural Development guide the implementation statistics, inventory and profiling forest management Thai Nguyen centre for environmental monitoring and protection (2009), Reviewed tolerance levels Cau River water, as a basis for building the socio-economic planning and environmental protection, Ha Noi 60 ... average slope of the basin is about 24%0 Cau river basin runs through in Bac Kan province that is the upstream area of the Cau River basin In Bac Kan province, the Cau river basin is located in districts... basin 2.2 Scope of research - The scope of space: Studying conducted in the stretch of the Cau river running through Bac Kan province Cau river basin in Bac Kan province includes Bac Kan town, Cho... Flow in the dry season in Cau river basin in Bac Kan province 51 Table 3.21 the frequency of runoff courses in some river basins of Cau stations in Bac Kan province 51 Table 3.22 The