Water

 The data on water pollution and water use are taken from the yearly report made by the RA National Statistical Service.

WATER SUPPLY NETWORK OF YEREVAN

N

System description

Flow Rate   m3/sec

D (mm)

L (km)

1

Katnaghbyur

Waterline 1

Waterline 2

Waterline 3

Waterline 4

2.49

0.015

0,875

1,1

0.5

 

150

900

900

700-100

 

15,5

18

26

31

2

Arzni

Waterline 1

Waterline 2

1,55

0.85

0.7

 

900

900

 

25

26.5

3

Arzakan

Gyumoush

1,1

700-800

1400

25

4

Aparan

1,05

700

61

  5

Garni

1,2

700-1000

35

6

Shor-shor

0,8

500

18

7

Arinj

0,13

500

3

8

Tsaravaghbyur

0,20

400-500

2

9

Dzoraghbyur

0,26

400

1

10

Yerevan Thermal Power Plant

0,24

400

1

11

Araratian

Shaft 1

Shaft 2

Shaft 3

Shaft 4

6,8

1,3

1,7

1,8

2,0

 

1200

1200

2x1000

2x1000

 

28

33

30

25

(The width of the alienation zone is 10m)     

According to the data acquired from the statistical reports made by water-supplying organizations, the water transit losses are very high. The daily amount of water supply per capita was 178 liters. Water losses in the water supply system are still very high. In 2000 the losses made 72,4% of the volume supplied to the consumers. The main cause for water loss is deterioration of water pipelines. Reportedly, it is necessary to replace 762,3 kilometers of pipe lines in the city of Yerevan. There have been recorded 1322 break-downs in the water supply system in 2000.

>

=

Waste Water Disposal

The waste waters disposed of in 2000 amounted to  126,913 million cubic meters, 20.3 % of which flowed into surface water intakes. In 27% of waste waters having been disposed of, the pollution level exceeded the sanitary standards, 99% of these being not purified at all, and the rest being partially purified.

 

The pipelines of the capital?s sewage management system and the biological treatment plant (BTP) need repair. About 270 km of pipelines (24% of the total 1,120 km) were laid in the 1930-ies and even earlier. The first stage of BTP was put into operation in 1972, designed for the treatment of 40% of the sewage. Current deterioration of the BTP is a serious hindrance to the sewage treatment. The second stage of the BTP with a 700,000 m3/day capacity, designed for the treatment of the remaining 60% of the sewage, is unfinished, as a result of which the sewage flows into Hrazdan river without any treatment.

 

(go to "Monitoring")

Natural Streams and Reservoirs of Yerevan

Hrazdan (Zangu) is a left-hand tributary of Arax. The length of Hrazdan is 141 km; the river basin (without Lake Sevan) occupies an area of 2,560 square kilometers, starts from Lake Sevan, flowing from the north-east to the south-west. Middle Hrazdan is meandering through a narrow, 120-150 m deep canyon alternating with V-shaped valleys. The river valley is 10-11 kilometers wide, marshy in some places, with terraces and landslides. There are picturesque columnar basalt formations on the vertical valley sides. The Lower Hrazdan Valley is gradually widening and the river flows through the Ararat Valley into Arax River at an elevation of 820m. The overall stream gradient is 1,100m; the average density of the river basin?s stream system is 0,49 km/km2. There are numerous creeks in the river system, 25 of which are longer than 10 km. Hrazdan is fed mainly by underground flows.  High flooding is in spring, with high-water periods in summer and autumn. The average stream discharge is 22,6m3/s, the maximum stream discharge is 138 m3/s, and the minimum stream discharge is 9 m3/s, making an annual flow of 712 million cubic meters. Hrazdan became of an exclusive importance for the national economy of Armenia after creation of the system of power plants and irrigation canals (Sevan-Hrazdan Cascade).

Getar is a left-hand tributary of Hrazdan. Getar is a mudflow stream, 24 km long, with a river basin occupying an area of 158 km2. Getar starts from the western slopes of Geghama Range, at 1,570 m elevation, flows through Yerevan into the Hrazdan River. It is fed by atmospheric precipitation and underground waters. High flooding is in spring. The annual average stream discharge is 14,4 l/sec, with the minimum in winter and the maximum is spring.

Yerevan Lake  is a men-made reservoir located in southwest Yerevan. It was built in the Hrazdan River`s Canyon in 1963-1966. Its elevation is 908 m, surface area - 95 ha, average depth - 8 m, maximum depth - 18 m, volume - 4.8 million cubic meters. The reservoir is fed by Hrazdan River. The water canals starting from the Yerevan Lake are irrigating the cultivated lands in Echmiadzin and Masis regions of Armenia. The Yerevan Lake is great significance in terms of creating landscape and microclimate, also for the townspeople`s rest zone situated in the Hrazdan Canyon. (go to map)