BRATSKOYE RESERVOIR

A view on the lakeshore
with an investigation vessel


Photo: I.N.Varfolomeeva

A. LOCATION

• Irkutsk Region, Russia.
• 52:45-56:15N, 100:35-103:50E; 402 m above sea level.

B. DESCRIPTION

Bratskoye Reservoir is situated at the upper part of the Angara River. It was formed in 1961 1967 by damming the Angara River near Bratsk City.
The general planner of this reservoir and hydroelectric power plant was the Saint Petersburg Department of the Institute "Hydroproject". The cost of this project development and construction was 789.2 million rubles including 213.63 million rubles for the reservoir construction.
Bratskoye Reservoir is of the channel type with long-term storage regulation.
The water resources of this man-made lake are widely used for hydroelectric power generation, navigation and transportation, fisheries, recreation and timber-rafting.
The capacity of the Bratsk hydroelectric power station amounts for to 4.5x1.0E+6 kWh.
This reservoir operates in a cascade with the reservoirs Irkutskoye (upstream) and Ust-Ilimskoye (downstream).
The drainage basin of Bratskoye Reservoir includes the drainage basins of Lake Baikal, Irkutskoye Reservoir and its own partial drainage basin between the dams of the Irkutsk and Bratsk hydroelectric power plants. The partial drainage basin accounts for 22% of the total drainage area and consists of two parts; north-eastern plain and south-western mountains. The plain part is situated on the Siberian Plateau formed by thick sedimentary rocks of Cambrian, Ordovician and Silurian systems. The mountain part is characterized by the presence of rocks from Archean to Quaternary period with mass intrusions of gneiss, crystalline slate with seams of quartzite and marble (Q).

C. PHYSICAL DIMENSIONS

Surface area [km2]	5,478
Volume [km3]	169.3
Maximum depth [m]	150
Mean depth [m]	31.1
Water level	Regulated
Normal range of annual water level fluctuation [m]	3.75
Length of shoreline [km]	7,400
Residence time [yr]	1.8
Catchment area [km2]	757,200 (157,530*)

* Part of the catchment area between the dams of Irkutsk and Bratsk hydroelectric power plants.

D. PHYSIOGRAPHIC FEATURES

D1 GEOGRAPHICAL

• Bathymetric map: Fig. ASI-61-1.
• Number of outflowing rivers and channels (name): 1 (Angara R.).

Fig. ASI-61-1
Bathymetric map [m].

D2 CLIMATIC (Q)

• Climatic data at Bratsk, 1984 1988

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Ann.
Mean temp. [deg C]	-20.5	-19.8	-10.8	-1.4	6.4	12.6	17.0	15.2	8.9	-0.2	-9.0	-17.4	-1.6
Precipitation [mm]	16.9	10.3	10.3	11.6	28.4	56.7	58.2	78.9	36.8	22.6	21.6	17.4	459.7

• Number of hours of bright sunshine (Bratsk, 1984 1988): 1,945 hr yr-1.
• Solar radiation (Khomutovo, 1984 1988): 12.27 MJ m-2 day 1.
• Water temperature [deg C]

Station 1, 1988
Depth [m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0.1	*1	*1	*1	0.8	3.0	6.5	10.8	17.4	13.7	8.6	3.1	*1
2	0.1	0.1	0.1	1.7	2.8	6.5	10.8	17.2	13.7	8.6	3.0	0.1
5	0.2	0.4	0.1	1.6	2.8	5.6	10.4	16.6	13.7	8.6	3.0	0.4
10	0.7	1.1	0.8	1.6	2.7	4.8	7.9	12.7	10.9	8.6	3.0	1.5
15	1.2	1.4	1.3	1.6	2.7	4.6	6.5	10.2	9.2	8.6	3.1	1.7
20	1.4	1.7	1.5	1.6	2.7	4.5	5.3	8.1	7.9	8.6	3.1	2.0
30	1.9	2.0	2.0	2.0	2.7	4.0	4.6	6.0	6.4	6.4	3.1	2.2
50	2.2	2.4	2.9	2.7	2.7	4.0	4.0	5.2	5.0	5.4	3.2	2.7
N*2	3.0	3.2	3.4	3.4	3.0	3.9	3.9	4.1	4.2	4.8	3.4	3.4

*1 Ice-covered. *2 Near bottom.

Station 2, 1988
Depth [m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0.1	-	-	-	-	-	11.2	12.1	12.3	-	7.2	-	-
2	-	-	-	-	-	-	11.0	11.9	-	-	-	-
5	-	-	-	-	-	-	11.9	11.7	-	-	-	-
10	-	-	-	-	-	-	10.2	11.6	-	-	-	-
N*	-	-	-	-	-	11.0	10.0	11.6	-	7.3	-	-

* Near bottom.

• Freezing period: From December to April, 150 200 days.
• Mixing type: Dimictic.
• Notes on water mixing and thermocline formation
  Thermocline is formed in the deepest northern part of the reservoir in summer (June September). In 1988 thermocline formation was observed at a depth of 5 10 m with temperature gradients of 0.5 0.8 deg C m-1.

E. LAKE WATER QUALITY (Q)

E1 TRANSPARENCY [m](2)

Station 1, 1975 (depth 103 m)
Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
3.0	3.7	4.0	5.0	9.2	5.5	3.8	7.0	3.8	5.0	5.0	5.0

Station 3, 1975 (depth 41 m)
Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
9.2	11.0	11.0	8.0	-	2.6	3.6	5.2	-	4.4	4.2	5.0

E2 pH

Station 1, 1975
Depth [m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0.5	-	7.60	7.45	7.70	7.70	7.55	8.75	8.15	7.55	7.10	7.60	7.65
B*	-	7.60	7.40	7.60	7.60	7.50	7.70	7.80	7.55	7.10	7.60	7.65

Station 3, 1975
Depth [m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0.5	7.80	7.40	7.50	7.60	-	8.60	8.85	7.70	-	7.35	7.70	7.60
B*	7.60	7.40	7.60	7.70	-	8.25	8.25	7.40	-	7.20	7.70	7.50

* Bottom.

E4 DO [mg l-1]

Station 1, 1975
D*1	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0.5	12.87	12.70	13.05	12.78	11.23	12.33	11.56	9.92	9.48	10.21	10.75	13.62
B*2	11.20	11.59	12.26	11.21	10.69	11.16	11.04	10.35	9.40	10.15	11.21	12.43
Station 3, 1975
0.5	14.24	12.35	12.53	11.87	-	12.69	10.67	10.03	-	10.67	10.03	11.86
B*2	12.79	11.23	12.36	11.19	-	12.75	10.05	9.15	-	10.83	10.44	13.10

*1 Depth [m] *2 Bottom.

E5 COD [mg l-1]

Determined by KMnO4 method.

Station 1, 1975
Depth [m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0.5	2.8	3.2	2.7	3.3	2.6	3.1	3.2	2.8	3.6	3.3	3.5	5.0
B*	3.6	3.1	3.0	2.7	3.1	3.1	3.2	2.9	4.0	3.0	4.1	4.1

Station 3, 1975
Depth [m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0.5	3.0	2.2	2.5	2.4	-	4.4	4.4	5.1	3.4	-	2.6	3.4
B*	3.0	2.7	2.3	2.7	-	3.2	2.8	3.4	4.0	-	3.7	3.5

Determined by K2Cr2O7 method.

Station 1, 1975
Depth [m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0.5	6.1	9.5	7.7	11.9	4.7	7.5	10.8	9.2	10.8	4.7	7.0	10.7
B*	6.1	9.5	6.9	7.5	4.7	6.0	9.3	10.1	11.5	6.2	8.7	8.2
Station 3, 1975
0.5	5.7	6.2	7.5	6.3	-	10.4	8.3	12.7	11.9	-	8.7	8.3
B*	5.7	6.2	7.5	7.9	-	14.9	5.0	6.3	9.6	-	6.1	8.3

* Bottom.

E6 CHLOROPHYLL CONCENTRATION [mg m-2](3)

For the whole reservoir
1976	1977	1978
23.3 28.7	19.6 24.2	35.1 96.7

E7 NITROGEN CONCENTRATION [mg l-1](2)

Mean for the whole reservoir, 1968 1976
	Surface	Bottom
Spring
- NH4+	0.02-0.21	0.02-0.45
- NO3	0.12-0.55	0.10-0.55
- NO2	0.003-0.030	0.005-0.023
Summer
- NH4+	0.02-0.55	0.04-0.50
- NO3	0.06-0.37	0.07-0.32
- NO2	0.002-0.011	0.002-0.016
Autumn
- NH4+	0.02-0.25	0.01-0.27
- NO3	0.14-0.69	0.07-0.70
- NO2	0.005-0.027	0.005-0.020
Winter
- NH4+	0.02-0.10	0.02-0.10
- NO3	0.42-0.79	0.46-0.75
- NO2	0.003-0.031	0.001-0.016

E8 PHOSPHORUS CONCENTRATION (Q)

• Total-P [mg l-1]

Station 1, 1975
Depth [m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0.5	0.026	0.018	0.014	0.018	0.009	0.015	0.013	0.005	0.006	0.003	0.019	0.019
B*	0.024	0.024	0.012	0.020	0.013	0.029	0.020	0.007	0.008	0.004	0.024	0.019

* Bottom.

Station 3, 1975
Depth [m]	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
0.5	0.000	0.000	0.000	0.003	-	0.008	0.005	0.004	-	0.004	0.005	0.005
B	-	0.000	0.000	0.004	-	0.009	0.004	0.008	-	0.003	0.022	0.006

F. BIOLOGICAL FEATURES

F1 FLORA (3)

• Floating macrophytes
  Polygonum amphibium, Callitriche hermaphroditica.
• Submerged macrophytes
  Myriophyllum spicatum, Potamogeton pectinatus, P. perfoliatus, P. lucens, Batrachium trichophyllum.
• Phytoplankton
  Aphanizomenon flos-aquae, Melosira granulata, M. islandica helvetica, Ceratium hirundinella, Anabaena sp., Stephanodiscus hantzschii, S. ulna var. danica, Fragilaria crotonensis, Asterionella formosa, Gymnodinium coeruleum, Uroglenopsis sp., Chroomonas acuta.

F2 FAUNA

• Zooplankton
  Mesocyclops leuckarti, Cyclops vicinus, C. kolensis, Daphnia longispina, Leptodora kindtii, Epischura baicalensis, Synchaeta pachypoda, Notholca intermedia, N. olchonensis, Polyarthra trigla, Asplanchna priodonta, Keratella cochlearis, Kellicottia longispina, Conochilus unicornis (4).
• Benthos: Gmelinoides fasciatus, Chironomus plumosus, Tubifex tubifex (3).
• Fish
  Esox lucius, Perca fluviatilis, Rutilus rutilus lacustris, Gymnocephalus cernua (3).

F3 PRIMARY PRODUCTION RATE [g O2 m-2 day 1](2)

Mean for the whole reservoir, 1977
	Jun	Jul	Aug	Sep	Oct
Net production	0.61-4.58	0.89-2.97	1.23-5.05	0.82-1.93	0.53-1.42
Dark respiration	0.67-7.74	2.27-7.75	2.81-8.92	1.47-6.64	0.97-3.07

Mean for the whole reservoir, 1978
	Jun	Jul	Aug	Sep	Oct
Net production	0.96-3.22	1.08-4.04	1.35-3.66	0.75-2.76	0.41-1.44
Dark respiration	1.71-6.78	2.08-7.17	3.21-6.57	1.97-6.54	0.67-2.70

F4 BIOMASS

• Biomass of phytoplankton [g m-3](5)

Mean for the whole reservoir
Year	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
1972	-	-	-	-	-	1.32	-	4.10	5.52	-	-	-
1973	-	-	-	-	-	4.63	3.28	8.80	12.75	0.33	-	-
1974	-	-	-	-	-	2.98	-	11.37	1.79	0.35	-	-
1975	-	-	-	-	-	3.12	-	10.64	0.67	0.14	-	-
1976	-	-	-	-	-	0.83	0.62	2.90	0.38	0.22	-	-
1977	-	-	-	-	-	2.43	0.72	2.38	1.15	0.26	-	-
1978	-	-	-	-	-	0.80	0.40	2.33	0.85	0.14	-	-

• Biomass of zooplankton [mg m-3](5)

Mean value for two parts of the reservoir (0 10 m layer)
Year	Mar		Jun		Aug
	I	II	I	II	I	II
1974	-	-	90.7	494.4	1,115.7	1,229.0
1975	-	-	90.4	619.2	2,865.5	2,330.2
1976	40.2	-	145.7	572.9	1,086.6	2,212.5
1977	34.4	64.5	145.6	402.5	1,249.2	468.8
1978	-	-	185.4	363.8	1,010.6	917.3

Year	Sep		Oct
	I	II	I	II
1974	908.0	509.9	180.7	183.0
1975	671.8	551.8	253.5	244.2
1976	801.7	731.5	344.5	464.5
1977	-	-	149.3	189.7
1978	560.3	589.6	369.2	251.0

• Biomass of Benthos [g m-2](5)
  
  1970,30.

F5 FISHERY PRODUCTS (6)

• Annual fish catch 850.[metric tons]

G. SOCIO-ECONOMIC CONDITIONS

G1 LAND USE IN THE CATCHMENT AREA

	Area [km2]	[%]
Natural landscape Woody vegetation	144,900	92
Agricultural land
- Crop field	7,630	5
- Pasture	5,000	3
Total	157,530	100

• Levels of fertilizer application on crop fields: Moderate.

G3 POPULATION IN THE CATCHMENT AREA (7) (1984)

	Population	Population density [km 2]	Major cities
Urban	1,357,000
Rural	107,000	0.68	Bratsk, Balagansk, Angarsk, Usoliye Sibirskoye
Total	1,464,000	9.29

H. LAKE UTILIZATION

H1 LAKE UTILIZATION (6)

Source of water, navigation (230,000 persons in 1983) and transportation (4,200,000 tons in 1983), sightseeing and tourism (120,000 persons in 1981), recreation (swimming, sport fishing), fisheries, electric power production and timber rafting (4,100,000 m3 in 1981).

H2 THE LAKE AS WATER RESOURCE (6) (1983)

	Use rate [1.0E+6 m3 yr-1]
Domestic	755
Irrigation	14.4
Industrial	320
Power plant	89,770
Special compensation flow for transport	2,600

I. DETERIORATION OF LAKE ENVIRONMENTS AND HAZARDS

I1 ENHANCED SILTATION

• Extent of damage: Not serious.
• Supplementary notes
  Erosion of the banks at a part of the reservoir: 20 45 m during 10 years.

I2 TOXIC CONTAMINATION

• Present status: Serious.
• Main contaminants, their concentrations and sources

Mean for the whole reservoir, 1990
Name of contaminant	Concentration in water [mg l-1]	Main sources
Phenol	0.001	Submerged trees
Oil products	0.13	Navigation
BOD	1.16	Submerged trees
pH	8.6	Submerged trees
NH4	0.03	Industry
NO2	0.002	Industry
Cu	0.001	Industry
Zn	0.006	Industry
Methylmercaptan	0.003
Formaldehyde	0.034

N. SOURCES OF DATA

17. Questionnaire filled by Dr. T. P. Gronskaya, Ms. T. E. Litova and Ms. I. Varfolomeeva, State Hydrological Institute, St. Petersburg, Russia.
1. Reference Book of the USSR Reservoirs, Part 1 (1988) 324 pp. Moscow.
2. Hydrometeorological Regime of the Bratskoye Reservoir (1976) 166 pp. St. Petersburg.
3. Proceedings of the USSR Hydrobiological Society, 25 (1983) 145 pp. Moscow.
4. Formation of Plankton and Hydrochemistry of the Bratskoye Reservoir (1973) 142 pp. Novosibirsk.
5. Primary Production of the Bratskoye Reservoir (1983) 110 pp. Moscow.
6. The Reservoirs of Siberia (Angara-Enisei Drainage Basin) (1987) 280 pp. Krasnoyarsk.
7. Atlas of the USSR (1984) 260 pp. Moscow.

* Publications cited were printed in Russian. The titles are tentatively translated into English.