1. Introduction

Water resources in the Aral Sea Basin, whose territory belongs to five states, are mostly used for irrigation and hydropower engineering. These water users require river runoff to be regulated with different regimes. The aim of the hydropower engineering is the largest power production and, accordingly, the utilization of the major portion of rivers annual runoff in winter, the coldest season of the year. Irrigation requires the largest water volume to be available in the summer,

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

during the vegetation period. River runoff regulation is exercised by large reservoirs which, along with hydropower stations, are operated as part of complex purpose hydroschemes. The largest hydropower stations have been constructed in the republics of the runoff formation zone in the upper reaches of the Amu Darya and Syr Darya rivers—in Kyrgyzstan and Tajikistan, while the major land areas to be irrigated are concentrated in the republics in the lower reaches of the rivers—Kazakhstan, Turkmenistan, and Uzbekistan. The problems of water resources use and the appropriate river runoff regulation were solved in the USSR by administrative command methods based on nationwide interests [1]. The situation has radically changed after the collapse of the Soviet Union and the formation of five independent states in Central Asia. The conflict of interests between hydropower engineering and irrigated farming has become evident and acquired transnational significance. What are the causes of the present-day conflict between irrigation and power engineering in the region? The first cause is the excessive development of irrigated farming in the region in the 1960s–1990s, resulting in a strict demand for practically complete regulation of river runoff, both seasonal and over-years, and its complete consumption for irrigated farming [2, 3].

the Soviet Union. In the Soviet period, irrigated farming was a priority in the use of water resources. At the same time, the hydropower engineering that was operated in the regime was unfavorable for the national interests of the countries in the upper reaches of the rivers.

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What are the ways to resolve this problem? Paradoxically as it may be, a radical solution of the conflict between irrigation and hydropower engineering will be their joint rapid development with the construction of new large HPPs with large-volume reservoirs, rather than the restriction or subordination of one of them. In the case of hydropower engineering, this implies the production of economic and clean power. As for irrigation, this implies an increase in the depth of long-term regulation of runoff and water availability for the areas already developed, as well as the potential for the development of new areas. The availability of several hydropower stations with reservoirs will allow the contradictions between hydropower engineering and irrigation to be resolved. Nowadays, the conflict between them arises because there is only one large hydropower facility with a reservoir in the basin of each of the major rivers in the region: the Toktogul HPP in Kyrgyzstan on the Syr Darya and the Nurek HPP in Tajikistan on the Vakhsh River. A single large hydroelectric complex on a river cannot exercise runoff regulation in two regimes simultaneously—irrigation and power ones. The construction of one large hydroelectric complex on each of the two rivers will radically change the situation. In this case, the upstream reservoir will operate in a purely power regime, while the downstream reservoir with the same volume will be able to re-regulate the runoff and even restore its natural regime. Moreover, it will be able to ensure runoff regulation in the interests of irrigation. The availability of more than two hydroelectric complexes with reservoirs will allow

Water relations between Central Asia republics during the Soviet Union time were regulated by "Complex Use and Protection of Water Resources Schemes" in Amu Darya and Syr Darya Basins.

The main purpose of working out basin "Schemes" was to define real volumes situated within the Amu Darya and Syr Darya basins and available water resources for using. It also provided their fair allocation among region republics, meeting all the water users' interests. It should be noticed that a number of important aspects were not considered and included in "Schemes," for the situation has greatly changed after 1980 (years of the last "Schemes" specification and completion of hydraulic range composition). Mainly, it concerns the ecologic acquirements and sanitarian clears thrown into rivers and channels. Overusing basin water in irrigational lands planned as maximum use by "Scheme" resulted in exhausting water resources and new problems: (1) deterioration of ecological condition, sometimes leading to ecological disaster in river lowlands of Aral Basin, (2) great pollution of river water with pesticides, herbicides, other

The Zeravshan River is one of the transboundary tributaries of the Amu Darya River that is formed in Tajikistan and that flows into Uzbekistan. The average flow of the Zeravshan River

The meteorological and hydrological monitoring of the Zeravshan River Basin conditions in the territory of the Republic of Tajikistan is conducted at four meteorological stations and the Dupuly hydrological station. The total area of the glaciers in the Zeravshan River Basin is 437.9 km2

Zeravshan glacier is the largest among the 632 glaciers with a length of 27.8 km and an area of

/sec [6, 7, 8].

. The

the situation to be improved even farther.

harmful elements and increase of water mineralization [1].

is about 5.0 km<sup>3</sup> with an average annual flow of 158 m<sup>3</sup>

There is no doubt that the main water arteries of Central Asia (CA)—the Amu Darya and Syr Darya—are important in the life of the regional population, in the survivability components of the biosphere and are a key factor in the development of two important areas—hydropower and agriculture. The diversity values of rivers' water flow have specific requirements for finding a balanced mechanism for their use excluding drain pollution and ecological imbalance. Such a multifunctional approach to sustainable use and protection of water resources is achieved by the implementation of integrated water resources management.

Transboundary water arteries make special demands for expansion and joint efforts for the development of regional standards and norms for the use of water resources, as enshrined in interstate agreements. Implementation of the interstate agreements aspects on various points of joint use of water resources is largely determined by the level of observation, measurement of meteorological, hydrological parameters, water quality and condition of water bodies and the efficiency of their use.

The Amu Darya is a Transboundary river of Central Asia and flows through four countries (Afghanistan, Tajikistan, Uzbekistan, and Turkmenistan) and is characterized by a length of 2400 km, the basin area of 534,739 km<sup>2</sup> . The main tributaries to the Amu Darya are Vakhsh, Pyanj and Zeravshan rivers.

In the 1990s, the area of irrigated land in the region rose to 9.0 million hectares. A sharp increase was observed in the energy sector. The total installed capacity of all power plants in the region reached by the mid-1990s of the twentieth century to 40 million kWt. Unfortunately, all these impressive results led to the same great negative consequences. The intensity of the disturbance processes of ecological balance in the region has sharply increased, especially in the Aral Sea and the Aral Sea zone, the salinization of lands and their desertification have increased and the quality of water has worsened in almost all sources. At the same time, by the 1970s, the water resources of the Syr Darya River Basin were almost completely depleted. This led to the frequency of water deficit, for example, in 2010, the water deficit in the region was 21.3 km<sup>3</sup> /year and turned into a global environmental problem in the region [4, 5]. The second cause is the severance of economic ties between Central Asian countries after the collapse of

the Soviet Union. In the Soviet period, irrigated farming was a priority in the use of water resources. At the same time, the hydropower engineering that was operated in the regime was unfavorable for the national interests of the countries in the upper reaches of the rivers.

during the vegetation period. River runoff regulation is exercised by large reservoirs which, along with hydropower stations, are operated as part of complex purpose hydroschemes. The largest hydropower stations have been constructed in the republics of the runoff formation zone in the upper reaches of the Amu Darya and Syr Darya rivers—in Kyrgyzstan and Tajikistan, while the major land areas to be irrigated are concentrated in the republics in the lower reaches of the rivers—Kazakhstan, Turkmenistan, and Uzbekistan. The problems of water resources use and the appropriate river runoff regulation were solved in the USSR by administrative command methods based on nationwide interests [1]. The situation has radically changed after the collapse of the Soviet Union and the formation of five independent states in Central Asia. The conflict of interests between hydropower engineering and irrigated farming has become evident and acquired transnational significance. What are the causes of the present-day conflict between irrigation and power engineering in the region? The first cause is the excessive development of irrigated farming in the region in the 1960s–1990s, resulting in a strict demand for practically complete regulation of river runoff, both seasonal and over-years, and its complete consumption

There is no doubt that the main water arteries of Central Asia (CA)—the Amu Darya and Syr Darya—are important in the life of the regional population, in the survivability components of the biosphere and are a key factor in the development of two important areas—hydropower and agriculture. The diversity values of rivers' water flow have specific requirements for finding a balanced mechanism for their use excluding drain pollution and ecological imbalance. Such a multifunctional approach to sustainable use and protection of water resources is

Transboundary water arteries make special demands for expansion and joint efforts for the development of regional standards and norms for the use of water resources, as enshrined in interstate agreements. Implementation of the interstate agreements aspects on various points of joint use of water resources is largely determined by the level of observation, measurement of meteorological, hydrological parameters, water quality and condition of water bodies and

The Amu Darya is a Transboundary river of Central Asia and flows through four countries (Afghanistan, Tajikistan, Uzbekistan, and Turkmenistan) and is characterized by a length of

In the 1990s, the area of irrigated land in the region rose to 9.0 million hectares. A sharp increase was observed in the energy sector. The total installed capacity of all power plants in the region reached by the mid-1990s of the twentieth century to 40 million kWt. Unfortunately, all these impressive results led to the same great negative consequences. The intensity of the disturbance processes of ecological balance in the region has sharply increased, especially in the Aral Sea and the Aral Sea zone, the salinization of lands and their desertification have increased and the quality of water has worsened in almost all sources. At the same time, by the 1970s, the water resources of the Syr Darya River Basin were almost completely depleted. This led to the frequency of water deficit, for example, in 2010, the water deficit in the region was

/year and turned into a global environmental problem in the region [4, 5]. The second

cause is the severance of economic ties between Central Asian countries after the collapse of

. The main tributaries to the Amu Darya are Vakhsh,

achieved by the implementation of integrated water resources management.

for irrigated farming [2, 3].

150 Achievements and Challenges of Integrated River Basin Management

the efficiency of their use.

Pyanj and Zeravshan rivers.

21.3 km<sup>3</sup>

2400 km, the basin area of 534,739 km<sup>2</sup>

What are the ways to resolve this problem? Paradoxically as it may be, a radical solution of the conflict between irrigation and hydropower engineering will be their joint rapid development with the construction of new large HPPs with large-volume reservoirs, rather than the restriction or subordination of one of them. In the case of hydropower engineering, this implies the production of economic and clean power. As for irrigation, this implies an increase in the depth of long-term regulation of runoff and water availability for the areas already developed, as well as the potential for the development of new areas. The availability of several hydropower stations with reservoirs will allow the contradictions between hydropower engineering and irrigation to be resolved. Nowadays, the conflict between them arises because there is only one large hydropower facility with a reservoir in the basin of each of the major rivers in the region: the Toktogul HPP in Kyrgyzstan on the Syr Darya and the Nurek HPP in Tajikistan on the Vakhsh River. A single large hydroelectric complex on a river cannot exercise runoff regulation in two regimes simultaneously—irrigation and power ones. The construction of one large hydroelectric complex on each of the two rivers will radically change the situation. In this case, the upstream reservoir will operate in a purely power regime, while the downstream reservoir with the same volume will be able to re-regulate the runoff and even restore its natural regime. Moreover, it will be able to ensure runoff regulation in the interests of irrigation. The availability of more than two hydroelectric complexes with reservoirs will allow the situation to be improved even farther.

Water relations between Central Asia republics during the Soviet Union time were regulated by "Complex Use and Protection of Water Resources Schemes" in Amu Darya and Syr Darya Basins.

The main purpose of working out basin "Schemes" was to define real volumes situated within the Amu Darya and Syr Darya basins and available water resources for using. It also provided their fair allocation among region republics, meeting all the water users' interests. It should be noticed that a number of important aspects were not considered and included in "Schemes," for the situation has greatly changed after 1980 (years of the last "Schemes" specification and completion of hydraulic range composition). Mainly, it concerns the ecologic acquirements and sanitarian clears thrown into rivers and channels. Overusing basin water in irrigational lands planned as maximum use by "Scheme" resulted in exhausting water resources and new problems: (1) deterioration of ecological condition, sometimes leading to ecological disaster in river lowlands of Aral Basin, (2) great pollution of river water with pesticides, herbicides, other harmful elements and increase of water mineralization [1].

The Zeravshan River is one of the transboundary tributaries of the Amu Darya River that is formed in Tajikistan and that flows into Uzbekistan. The average flow of the Zeravshan River is about 5.0 km<sup>3</sup> with an average annual flow of 158 m<sup>3</sup> /sec [6, 7, 8].

The meteorological and hydrological monitoring of the Zeravshan River Basin conditions in the territory of the Republic of Tajikistan is conducted at four meteorological stations and the Dupuly hydrological station. The total area of the glaciers in the Zeravshan River Basin is 437.9 km2 . The Zeravshan glacier is the largest among the 632 glaciers with a length of 27.8 km and an area of 132.6 km2 . According to the Agency of Hydrometeorology of the Republic of Tajikistan, there have been significant changes of geometric dimensions and mass loss of Zeravshan glacier during the period 1927–1991. The glacier retreated 88–94 m/year for the period 1991–2001 and its area decreased by 700,000 m2 and it is expected to decrease by 30–35% by 2050 [6, 9]. The next section provides an analysis of the Zeravshan River Basin meteorological condition.

2. Objects and methodology

rological stations were used.

Figure 1. Amu Darya River Basin [32].

phases of the low and high duration cycles [6].

The object of study is the Vakhsh River and its tributaries—Surkhob and Obikhingou—by use of water discharge data corresponding to rivers from Hydroposts: on the Surkhob-Garm Hydropost; Obikhingou river—Tavildara-Yozgand; on the Vakhsh river—Darband for the period 1960–2012. For estimation of the meteorological conditions of the Kyzilsu, Obikhingou and Vakhsh rivers Basin, the meteorological data of the Lyakhsh, Tavildara and Garm meteo-

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The differential integral curves of average annual discharge are used to identify periods with high and low water run-off. The differential integral curve takes into account the fluctuations of the flow over relatively short periods. It is defined by summing the deviations of modular coefficients from the middle, that is, the ordinates are calculated as Σ (K1). Thus, the ordinates of the curve at the end the cumulative sum of the annual modular coefficients gives the deviations from the long-term average (K = 1). The use of differential integral curves gives a vision of cyclical fluctuations without the effect of the boundaries displacement between the

The Dehavz station meteorological data for the period 1931–2011 were used as it is close to the Zeravshan glacier and Iskanderkul in the Yagnob River Basin. Water flow of the Zeravshan

The problem of the water quality change and development of mechanisms of its control is still actual and concerns not only the separately taken country of Central Asia (CA) but also all the states of the region. Nowadays one of the most polluted rivers of Central Asia is Zeravshan River. The capacity of this water is changed under the influence of collector drainage water of irrigating basin zone and wastewater of Samarqand, Kattakurgan, Navoi, and Bukhara cities. Mineralization of water exceeds from origin to estuary: from 0.27–0.30 to 1.5–1.6 g/l. The most exceed of maximum permissible concentration (MPC) among heavy metals is observed in Cr and Zn. Moreover, in Zeravshan River high amounts of antimony was found and its phenol pollution composes 3–7.5 MPC [1]. The problem of water quality in transboundary river basins, in particular in the Zeravshan River Basin, is compounded by the fact that up to now there is no network sharing of information regarding the quality of the waterways between the neighboring states of Central Asia. Herewith, a uniform standard for assessing of the anthropogenic load degree on geoenvironmental systems (maximum permissible concentration) is not developed. The problem of water quality of the Zeravshan River is mostly associated with its pollution by wastewater of the Anzob mountain-concentrating combine—the mining enterprise for extraction and enrichment of mercury-antimony ores of the Dzidzikurut deposit [10–18].

The Vakhsh River is the main river of the Republic of Tajikistan and one of the tributaries of the Transboundary Amu Darya River in Central Asia. It has a length of 691 km and the area of the basin is 39,160 km<sup>2</sup> . The Vakhsh River originates when the Surkhob and Obikhingou Rivers merge at a height of 1151 m. The right inflow to the Vakhsh Rivers, the Surkhob River has a length of 81 km, and the basin covers an area of 1760 km<sup>2</sup> at an average altitude of 3140 m. There are 246 glaciers in the Sorbog River Basin covering a total area of 105.6 km2 . The left component of the Vakhsh, the Obikhingou River, is 196 km long by basin area of 6660 km<sup>2</sup> [6].

The Pyanj River is one of the tributaries of the Transboundary Amu Darya River in Central Asia by a length of 921 km and a basin area of 114,000 km2 . The average value of the water flow is about 1032 m<sup>3</sup> /s. The total area of glaciation of the Pyanj River Basin is 3767 km<sup>2</sup> [19].

It is quite natural that the formation of the basic characteristics and the water quality of the main river runoff is the result of the imprint of the properties and parameters of its tributaries with prehistory meteorological conditions and the condition of its feeding sources (ice, snowice, rain, etc.). Therefore, the monitoring of hydrological characteristics, the study of the chemical composition of the main rivers tributaries and thus the creation of a database on the river basin meteorological conditions, hydrological parameters and degree of contamination are the pledge for preparation of the reliable information about the main river.

This chapter presents the results of many years' studies of the hydrological parameters, hydrochemical and meteorological conditions of the basins of the Vakhsh, Zeravshan and Pyanj rivers—the main tributaries of the Amu Darya.
