LAKE BA BE

A view from the lakeside

Photo.
Photo: Mai Dinh Yen


A. LOCATION


B. DESCRIPTION

    The freshwater Lake Ba Be is the only significant natural upland lake in the North of Viet Nam. It was formed by combined tectonic force and severe erosion in karst area. Surrounding limestone hills rise to 500 600 above sea level. There are a number of caves in this limestone area: the most famous is Puong Grotto through which the Nang River flows.
    The lake consists of three parts, Pe leng, Pe lu and Pe lam; hence the name Ba (three) Be (sea). It measures 9 km in total length, with the width between 0.2 km and 1.7 km. The average depth varies from 17 m to 23 m, the maximum depth reaching 29 m. Ba Be is connected with the Nang River by Be Cam Channel, to which the lake water drains during the dry season. The lake thus serves as a natural reservoir for the Nang River system, while Dau Dang Waterfall plays a role of natural dam for the lake.
    The beautiful and magnificent scenery of Ba Be and its surroundings has considerable potential for both national and international tourism. The lake and forests around it are designated as a protected area by the government. The lake is also important for the life of the local people belonging to an ethnic minority group Tay (total population 1,283 in 184 families in 1990) as the source of water, navigation and transportation routes, and fishing ground (Q).

C. PHYSICAL DIMENSIONS

    Surface area [km2] 4.5
    Volume [km3] 0.090
    Maximum depth [m] 29
    Mean depth [m] 18
    Normal range of annual water level fluctuation [m] 2.8
    Length of shoreline [km] 22
    Catchment area [km2] 454

D. PHYSIOGRAPHIC FEATURES (Q)

D1 GEOGRAPHICAL

    Fig. ASI-64-1
    Sketch map of the lake (Q).

D2 CLIMATIC
    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann.
    Mean temp. [deg C] 13.9 15.1 18.7 22.7 26.0 26.9 27.1 26.7 25.6 22.7 18.7 15.0 21.6
    Precipitation [mm] 16 34 48 94 173 213 291 263 182 84 27 20 1,445
    * About 100 km northeast of the lake.
    Station II, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S*1 - - - 28.0 - - - - 29.5 - - 17.0
    3 - - - 25.0 - - - - 28.8 - - 17.0
    6 - - - 24.8 - - - - 27.6 - - 16.4
    10 - - - 24.8 - - - - 27.2 - - 16.4
    15 - - - 24.6 - - - - 27.2 - - 16.4
    B*2 - - - 24.4 - - - - 27.2 - - 16.4
    *1 Surface. *2: 0.5 m above bottom.

E. LAKE WATER QUALITY (Q)

E1 TRANSPARENCY [m]
    Station II, 1975: 0.55 2.9; mean: 1.40.
E2 pH
    Station II, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S*1 - - - 8.4 - - - - 8.4 - - 7.1
    3 - - - 7.8 - - - - 8.4 - - 7.1
    6 - - - 7.3 - - - - 8.2 - - 7.1
    10 - - - 7.2 - - - - 8.0 - - 7.0
    15 - - - 7.1 - - - - 7.8 - - 7.0
    B*2 - - - 7.1 - - - - 7.5 - - 7.0
    *1 Surface. *2 Bottom.
E4 DO [mg 1]
    Station I, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S*1 - - - 5.82 - - - - 12.37 - - 3.52
    3 - - - 3.60 - - - - 7.52 - - 3.25
    6 - - - 2.08 - - - - 4.08 - - 3.38
    10 - - - 0.96 - - - - 1.30 - - 3.22
    15 - - - 0.67 - - - - 0.00 - - 3.22
    B*2 - - - 0.16 - - - - 0.00 - - 3.12
    *1 Surface. *2 Bottom.
    Station II, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S - - - 5.90 - - - - 9.92 - - 1.28
    3 - - - 4.10 - - - - 9.12 - - 1.36
    6 - - - 1.90 - - - - 3.20 - - 1.68
    10 - - - 1.08 - - - - 0.80 - - 1.60
    15 - - - 0.48 - - - - 0.00 - - 1.12
    B - - - 0.08 - - - - 0.00 - - 0.90
    Station III, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S - - - 4.56 - - - - 9.92 - - 1.52
    3 - - - 3.30 - - - - 8.32 - - 1.52
    6 - - - 0.55 - - - - 4.08 - - 1.60
    10 - - - 1.04 - - - - 0.80 - - 1.92
    15 - - - 0.48 - - - - 0.00 - - 2.00
    B - - - 0.08 - - - - 0.00 - - 1.36
E5 COD [mg 1]
    Station I, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S*1 - - - 6.59 - - - - 3.86 - - 3.84
    3 - - - 5.05 - - - - 2.26 - - 5.60
    6 - - - 3.71 - - - - 2.00 - - 6.28
    10 - - - 3.71 - - - - 3.75 - - 6.93
    15 - - - 2.75 - - - - 3.20 - - 6.00
    B*2 - - - 2.30 - - - - 4.50 - - 6.00
    *1 Surface. *2 Bottom.
    Station II, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S - - - 2.40 - - - - - - - 4.40
    3 - - - 4.00 - - - - 4.00 - - 2.80
    6 - - - 4.21 - - - - 3.20 - - 4.00
    10 - - - 5.30 - - - - 5.20 - - 4.44
    15 - - - 2.00 - - - - 2.00 - - 5.60
    B - - - 1.60 - - - - 5.60 - - 6.40
    Station III, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S - - - 4.00 - - - - 5.60 - - 4.40
    3 - - - - - - - - 4.00 - - 7.20
    6 - - - 3.60 - - - - 5.60 - - 4.00
    10 - - - - - - - - 2.00 - - 6.40
    15 - - - 5.20 - - - - - - - 5.00
    B - - - 5.20 - - - - 4.00 - - 8.40
E7 NITROGEN CONCENTRATION
    Station I, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S*1 - - - tr*3 - - - - 0.02 - - 0
    3 - - - tr - - - - 0.04 - - 0
    6 - - - tr - - - - 0.02 - - 0
    10 - - - 0.16 - - - - 0.10 - - 0
    15 - - - 0.30 - - - - 0.40 - - 0
    B*2 - - - 0.30 - - - - 1.00 - - 0
    *1 Surface. *2 Bottom. *3 Trace amount.
    Station II, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S - - - tr - - - - 0.25 - - 0
    3 - - - tr - - - - tr - - 0
    6 - - - tr - - - - tr - - 0
    10 - - - tr - - - - tr - - 0
    15 - - - 0.85 - - - - 0.75 - - 0
    B - - - 0.90 - - - - 1.00 - - 0
    Station III, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S - - - 0.05 - - - - 0.50 - - 0
    3 - - - 0.05 - - - - 0.70 - - 0
    6 - - - 0.07 - - - - 0.00 - - 0
    10 - - - 0.90 - - - - 0.15 - - 0
    15 - - - 0.90 - - - - 0.50 - - 0
    B - - - 0.90 - - - - 0.70 - - 0
    Station I, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S - - - 0.20 - - - - tr - - 0
    3 - - - 0.30 - - - - tr - - 0
    6 - - - 0.50 - - - - tr - - 0
    10 - - - 0.50 - - - - 0.04 - - 0
    15 - - - tr - - - - tr - - 0
    B - - - 0.30 - - - - tr - - 0
    Station II, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S - - - 0.50 - - - - 0 - - 0
    3 - - - 1.00 - - - - 0 - - 0
    6 - - - 1.50 - - - - 0 - - 0
    10 - - - 4.00 - - - - 0 - - 0
    15 - - - 0.30 - - - - tr - - 0
    B - - - 0.10 - - - - 0.12 - - 0
    Station III, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S - - - 1.50 - - - - 0 - - 0
    3 - - - 4.00 - - - - 0 - - 0
    6 - - - 0.70 - - - - 0 - - 0
    10 - - - 0.25 - - - - 0 - - 0
    15 - - - tr - - - - tr - - 0
    B - - - tr - - - - 0.25 - - 0
E8 PHOSPHORUS CONCENTRATION
    Station I, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S*1 - - - 0.026 - - - - 0.030 - - 0.039
    3 - - - 0.026 - - - - 0.020 - - 0.039
    6 - - - 0.026 - - - - 0.020 - - 0.039
    10 - - - 0.027 - - - - 0.020 - - 0.034
    15 - - - 0.027 - - - - 0.020 - - 0.030
    B*2 - - - 0.027 - - - - 0.020 - - 0.030
    *1 Surface. *2 Bottom.
    Station II, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S - - - 0.026 - - - - 0.027 - - 0.026
    3 - - - 0.026 - - - - 0.030 - - 0.039
    6 - - - 0.028 - - - - 0.017 - - 0.032
    10 - - - 0.030 - - - - 0.020 - - 0.032
    15 - - - 0.030 - - - - 0.017 - - 0.032
    B - - - 0.030 - - - - 0.028 - - 0.032
    Station III, 1975
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    S - - - 0.026 - - - - 0.025 - - 0.039
    3 - - - 0.026 - - - - 0.027 - - 0.039
    6 - - - 0.026 - - - - 0.020 - - 0.039
    10 - - - 0.026 - - - - 0.018 - - 0.032
    15 - - - 0.026 - - - - 0.018 - - 0.032
    B - - - 0.026 - - - - 0.018 - - 0.032

F. BIOLOGICAL FEATURES (Q)

F1 FLORA F2 FAUNA F4 BIOMASS F5 FISHERY PRODUCTS F6 PAST TRENDS
    Fish production has been decreasing.
F7 NOTES ON THE REMARKABLE CHANGES OF BIOTA IN THE LAKE IN RECENT YEARS
    Some species, particularly molluscan species such as Sinanodonta jourdyi., are rare now. Introduced fish species; Tilapia mossambica, is causing disturbance of native biocenosis.

G. SOCIO-ECONOMIC CONDITIONS (Q)

G1 LAND USE IN THE CATCHMENT AREA (1990)
    Area [km2] [%]
    Natural landscape
    - Woody vegetation 227 50
    - Herbaceous vegetation 159 35
    - Swamp 2 0.4
    Agricultural land Crop field
    - Shifting cultivation 40 8.8
    - Wet paddy field 5 1.1
    Residential area (5 villages) 20 4.4
    Others 1 0.2
    Total 454 100
G2 INDUSTRIES IN THE CATCHMENT AREA AND THE LAKE (1990) G3 POPULATION IN THE CATCHMENT AREA (1990)
    Population Population density [km 2] Major cities
    Total 16,000 35 None

H. LAKE UTILIZATION (Q)

H1 LAKE UTILIZATION
    Source of water, navigation and transportation, sightseeing and tourism, and fisheries.
H2 THE LAKE AS WATER RESOURCE (1990)
    Domestic water for local people.

I. DETERIORATION OF LAKE ENVIRONMENTS AND HAZARDS (Q)

I1 ENHANCED SILTATION I2 TOXIC CONTAMINATION
    No information.
I3 EUTROPHICATION
    Moderate eutrophication due to the inflow of domestic wastewater.

J. WASTEWATER TREATMENTS (Q)

J1 GENERATION OF POLLUTANTS IN THE CATCHMENT AREA
    (b) No sources of significant pollution.
J3 SANITARY FACILITIES AND SEWERAGE
    None.

K. IMPROVEMENT WORKS IN THE LAKE (Q)

    None.

L. DEVELOPMENT PLANS (Q)

    A development plan for fisheries (rational exploitation) was implemented during 1968 1972, but was now suspended.
    The development plan of the whole area (the lake and the surrounding forests) as a National Park is being drafted.

M. LEGISLATIVE AND INSTITUTIONAL MEASURES FOR UPGRADING LAKE ENVIRONMENTS (Q)

M1 NATIONAL AND LOCAL LAWS CONCERNED M2 RESEARCH INSTITUTES ENGAGED IN THE LAKE ENVIRONMENT STUDIES
  1. University of Hanoi
  2. Ministry of Fisheries, Research Institute for Aquaculture No. 1
  3. Ministry of Forestry, Institute of Forest Planning and Inventory

N. SOURCES OF DATA

  1. Questionnaire filled by Prof. Mai Dinh Yen, Laboratory of Ecology, Department of Environmental Science, University of Hanoi, Hanoi.
  2. Nguyen, V. H. (1976) personal communication (biological basis and fish resources).
  3. Mai, D. Y., Tran, M. T. & Rguyen, V. H. (1991) Economical-scientific -technical analysis for planning Ba Be Lake as natural reserve for conservation of the gene pool of living aquatic resources. National Symposium on Sciences and Technics, Hanoi.