Forum on the Caspian, Aral and Dead Seas-Perspective of Water Environmental Management and Politics


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Water Level Change and Agricultural Irrigation in the Aral Sea

Yoshihiro Takano
Desert and Human Geoscience Department, Engineering Division, Shimizu Corporation

The Syrdarya River Basin was surveyed in 1992 and 1993 along with the Japan GIF Research Foundation. Based on field survey and Landsat data analysis, the outline of irrigated agriculture in the area was studied.

1. Introduction

The Japan GIF Research Foundation is contributing towards the environmental restoration of the Aral sea basin and reconstruction of the regional economy under international cooperation.

As a part of this work, the Syrdarya river basin ranging from the midstream to the downstream, the area around Aralsk located at the northern end of the Aral sea and the dried up seabed located at the northeast riverbank of the Aral sea were surveyed from 1992 to 1993. In addition, by analyzing the MSS, the newest Landsat data has been examined. This paper introduces the investigation results, current situation and problems regarding the irrigated agriculture.

2. Water use in the Aral Sea basin

The composition of water demand of the Syrdarya and Amudarya basin in 1987 were summarized based on Dr. Zhu's data (figure 1). The volume of demand water in the Amudarya and Syrdarya basins are respectively 53.55 km³ and 43.77 km³, and 97.32 km³in total.

The agricultural water use covers 81.6% in all, water utilized for the agricultural land was 44.80 km³ in Amudarya , 34.58 km³ in Syrdarya and 79.38 km³ in total.

The composition of planted crops in the irrigated agricultural land of the Syrdarya and Amudarya basin in 1987 and the composition of the water demand for each planted crops are indicated in figure 2. The Syrdarya basin has less cotton fields than the Amudarya basin and is characterized by grassy pasture and paddy rice planting. The volume of water demand per planted area for each crop is indicated in table 1. Paddy rice showed the biggest water demand followed by grass in both basins.

Although drainage water was recycled to irrigation, it is important to understand the actual condition in both paddy rice and grass land which require the largest quantity of irrigation water, in order to consider the water conservation and environmental improvement plan in the future.

3. Land Use and Agriculture Around Kzyl-Orda

The irrigated agricultural land has expanded on both sides of Syrdarya. According to the observed data in 1987, which is analyzed by the MSS, Landsat data, approximately 502 x 103 ha of the irrigated agricultural land has existed around Kzyl-Orda and it deserves 15% of all irrigated area in the Syrdarya basin. The irrigated field consists of 130 x 10³ ha (26%) for the paddy field, 195 x 10³ ha (39%) for the upland field (except paddy rice) and 177 x 10³ ha (35%) for the fallow land.

According to local people, the crop rotation of a eight years period including one year's fallow interval has been introduced for the purpose of evasion of the accumulated cropping obstacles by salinization and the water conservation. If an eight year rotation is practiced in all agricultural land, the fallow land accounts for 12.5%.

However, on the basis of the Landsat data analysis, fallow land accounts for 35%. The causes of this difference are considered to be as follows:
i) The actual crop rotation patterns may have diversification.
ii) The crop rotation is not practiced as planned.
iii) Planted area has decreased due to lack of agricultural materials, and
iv) The increase of the abandoned agricultural land caused by salt damage.

A model figure of a typical division of the irrigated farm land is shown in figure 3, and the outline cross section is indicated in figure 4. The basic plot of paddy fields and upland fields is 2 ha, and operational unit is 20 ha of the field and a basic block for one irrigation unit is developed for 80-140 ha. A farm unit in which some farmers cultivated in joint execution works, managed 1,000 ha on average.

Yield of paddy rice averaged 4.5 tons/ha in Kazakh and 5.2 tons/ha in Kzyl-Orda. While the main agricultural product is rice in Kazakh, its production in 1993 was about 30 million tons. Since domestic consumption is only 7 million tons per year, surplus rice needs to be sold outside the Republics. The government is putting a great deal of effort into the export of surplus agricultural products but export is getting difficult after the collapse of the Soviet Union. Under these circumstances, the government does not intend to increase the irrigated area for increasing rice production.

The problems related to irrigated agriculture are as follows:

i) The rice production in the Syrdarya river basin has a history of war against reed invasion and it still continues today. If we can get rid of the reeds, the yield in the field and irrigation efficiency in the canal will be improved.

ii) The land leveling of the field is rather irregular. For this reason, irrigation water is not used effectively and the irregular growth of rice has occurred.

iii) The maintenance of canals is poor. Though canals have concrete linings around head works and city areas, most canals are unlined and over-percolation has occurred. The surface of the earth canal has collapsed. Many buried canals have been found. Because of a higher level of sub-canals over the main one, the water level of the main canal has risen up to lead water to sub-canals. Some water pumps are out of order and they have not been repaired yet due to financial problems.

The main paddy rice varieties are Kuban-3 and Marjan and both are high yielding varieties with lodging resistant characteristics. A recent released high yielding variety does not require a high level of pesticide application. However, the field operational management has several problems such as many weeds growing and water management.

4. Irrigated agriculture around Novokazalinsk

Around Novokazalinsk irrigated agriculture areas are located at the lowest reaches of Syrdarya. The irrigated agricultural land has expanded on both sides of Syrdarya. According to the analysis of the MSS Landsat data in 1987, the irrigated agricultural land extended about 59 x 10³ ha, of which about 41 x 10³ ha (69%) was for paddy fields, 4 x 10³ ha (39%) was for upland fields (except paddy rice) and 14 x 10³ ha (35%) was for fallow lands. In this area the livestock industry is more important than that of Kzyl-Orda. Livestock feeds are produced in natural vegetation areas of the old delta. There are about 46 x 10³ ha of upland fields in this area utilizing surplus water and drainage from irrigation system where they have produced reed. It is common that crop rotation field introduce alfalfa.

5. Conclusion

Based on further studies on land and water use, we intend to prepare an environmental management plan for the Aral Basin. We consider that the first step has been completed for the preparation of the plan.

Table 1. Water Demands per Irrigation Area of Amudarya and Syrdarya Basin

	Water demand (mm/year)
Planting	Amudarya	Syrdarya
Raw Cotton	940	840
Paddy Rice	2,840	2,690
Grain	840	1,020
Grass	1,110	1,040
Vegetable	920	970
Orchard	870	790

(Calculated by Z. Zhu, 1991)

(larger image)
Figure 1: Water Demands of Amudarya Basin and Syrdarya Basin (1987) in %

(larger image)
Figure 2: The Composition (%) of Planted Crops in the Irrigated Agricultural Land and
the Composition of Water Demands in the Amudarya and Sydarya Basin (1987)

(larger image)
Figure 3: Model Figure of the Irrigated Agricultural Land Block (in meters)

(larger image)
Figure 4: The Model Cross Section of Irrigation Agricultural Land (unit: meters)

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