SANCHA-HU (LAKE SANCHA)

A view on the lake

Photo.
Photo: Sichuan Environmental Protection Committee


A. LOCATION

  • Sichuan Province, P.R. China.

  • 30:20N, 104:15E; 465 m above sea level.


B. DESCRIPTION

    Sancha-hu (Lake Sancha) is a man-made lake. The construction work was designed by the Sichuan Survey and Design Institute for Water Resources and Electric Power, and implemented by the government of Jianyang County. The work was started in March 1975, and completed in February 1977.
    The site of the reservoir is a transitional zone between Longyuan Mountains and the hilly area covered by terra rossa which belongs to an inland lake sedimentary phase of Upper Jurrasic and Cretaceous Periods. The surrounding hills have gentle slopes and are made of relatively hard rocks. The quality of air and water comes up to No. 1 grade of National Environmental Standards.
    The purpose of damming was to store water for irrigating farmlands, now amounting to 39,700 hectares. Meanwhile fish culture and uses for recreation/tourism have been developed. The reservoir with its natural scenic beauty and nearby historic sites is now a famous touristic site in the western part of Sichuan Basin (Q).

C. PHYSICAL DIMENSIONS (Q)

    Surface area [km2] 27
    Volume [km3] 0.2235
    Maximum depth [m] 32.5
    Mean depth [m] 8.2
    Water level Regulated
    Normal range of annual water level fluctuation [m] 4.5
    Length of shoreline [km] 240
    Residence time [yr] 0.7
    Catchment area [km2] 161

D. PHYSIOGRAPHIC FEATURES

D1 GEOGRAPHICAL
  • Sketch map: Fig. ASI-49-01.

  • Names of main islands: Hua, Yueling and Niao.

  • Number of outflowing rivers and channels (name): 1 (Dongfeng Channel).

    Fig. ASI-49-01
    Sketch map of the lake (Q).

D2 CLIMATIC
  • Climatic data at Jiunyang

    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann.
    Mean temp. [deg C] 6.3 8.3 13.2 18.2 21.8 24.4 26.5 26.3 21.9 17.3 12.6 8.2 17.1
    Precipitation [mm] 10 13 19 51 72 141 197 179 136 46 20 9 830
  • Number of hours of bright sunshine: 1,224 hr yr-1.

  • Solar radiation: 10.27 MJ m-2 day-1.

  • Water temperature [deg C]

    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    0.5 - - 13.0 - 20.0 - 31.0 26.0 25.0 19.0 18.0 13.0
  • Freezing period: None.

  • Mixing type: Monomictic.


E. LAKE WATER QUALITY

E1 TRANSPARENCY [m] (1985-1988)
    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    - - - - 1.2 - - 1.0 - - - -
E2 pH
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    0.5 - - 8.3 - 7.7 8.0 8.4 7.0 7.9 7.9 7.5 7.6
E3 SS [mg l-1] (1985-1988)
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    0.5 - - 9.0 - 2.6 - - 8.7 - - - -
E4 DO [mg l-1] (1985-1988)
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    0.5 - - 10.1 - 7.7 7.8 6.0 7.4 5.4 8.1 8.7 7.7
E5 COD [mg l-1] (1985-1988)
    Determined by KMnO4 method.
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    0.5 - - 2.7 - 2.8 4.3 2.7 2.8 2.9 2.8 2.2 2.2
E6 CHLOROPHYLL CONCENTRATION [micro l-1] (1987,1989)
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    0.5*1 3.64 3.89 4.10 3.00 - 3.64 - 4.49 7.74 - 3.36 -
    0.5*2 2.42 2.36 1.99 1.45 - 2.32 - 1.98 2.03 - 3.33 -
    *1 1987 *2 1989
E7 NITROGEN CONCENTRATION (1985-1988)
  • Total-N [mg l-1]

    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    0.5 - - - - 0.06 - - 0.01 - - - -
E8 PHOSPHORUS CONCENTRATION [mg l-1] (1985-1988)
  • Total-P [mg l-1]

    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    0.5 - - - - 0.02 - - 0.016 - - - -
E9 CHLORIDE CONCENTRATION [mg l-1] (1985-1988)
    Depth [m] Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    0.5 - - - 4.92 - 3.9 3.5 5.19 3.5 3.5 2.5 3.2

F. BIOLOGICAL FEATURES

F5 FISHERY PRODUCTS (Q)
  • Annual fish catch [metric tons]
    1988: 250.
  • Fishery products other than fish [metric tons]
    1988: 15.

H. LAKE UTILIZATION

H1 LAKE UTILIZATION
    Sources of water, sightseeing and tourism (no. of visitors in 1988: 200,000), recreation (swimming) and fisheries.

I. DETERIORATION OF LAKE ENVIRONMENTS AND HAZARDS

I1 ENHANCED SILTATION
  • Extent of damage: Not serious.

I2 TOXIC CONTAMINATION (1989)
  • Present status: Detected but not serious.

  • Main contaminants, their concentrations and sources

    Name of contaminants Concentration Water [ppm]
    Pb 0.1
    Cd 0.004
    Zn 0.03

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

M2 INSTITUTIONAL MEASURES
  1. Chegdu Survey & Design Institute for Water Resources & Electric Power Ministry
  2. Sichuan Survey & Design Institute for Water Resources & Electric Power
  3. Neijiang Research & Monitoring Institute for Environmental Protection
  4. The Administration Bureau of Sancha-hu
M3 RESEARCH INSTITUTES ENGAGED IN THE LAKE ENVIRONMENT STUDIES
    l) Sichuan Research & Monitoring Institute for Environmental Protection
  1. Neijiang Research & Monitoring Institute for Environmental Protection

N. SOURCES OF DATA

  1. Questionnaire filled by Sichuan Environmental Protection Committee, Chengdu, Sichuan, China.