Preface

The hydropower sector has gone through more than 140 years since the world's first hydropower station was established in 1878. Hydropower construction in most developed countries unfolded from the 1920s to the 1960s and entered a stable development stage in the 1970s, with hydropower resources in Switzerland and France almost fully exploited in the 1980s. The upsurges of hydropower construction in Asia, Africa, Latin America, and the United States began in the 1960s. Since then, emerging and developing economies have been leading global hydropower growth, while the hydropower infrastructure of developed countries is gradually aging. The average service life of hydropower stations is close to 50 years in North America and 45 years in Europe. Signs of risks from aging infrastructure are observed all over the world. Examples include the flooding of the Sayano-Shushenskaya Hydropower Station in Russia in August 2009 and the damage to the spillways of the Oroville Dam in the United States in 2017, prompting the evacuation of residents around the dam.

Hydropower has represented a decreasing share of power generation in advanced economies since 2000. Even so, global installed hydropower capacity has increased by 70% over the past two decades. Globally, about half of the economic potential of hydropower remains untapped, with a particular high of nearly 60% in emerging and developing economies. In addition, there are already a massive number of hydropower facilities that have been providing affordable and reliable renewable power on demand for decades. Modern upgrades are needed to ensure that they can contribute to power security in a sustainable manner in the coming decades.

Hydropower is not only a maturely used clean energy source, but it is also a highly flexible energy storage system. Compared with nuclear power, coal power, and even gas-fired power, hydropower is quicker in regulating electricity production, so it can efficiently serve peak shaving in the future when wind power, solar, and other intermittent power sources are applied on a large scale. In 2020, hydropower accounted for 17% of global power generation, the third-largest source of electricity after coal and natural gas. From 2021 to 2030, global installed hydropower capacity is expected to keep expanding by 17% to reach 230 GW, according to a report from the International Energy Agency. In this context, a challenge for global sustainable hydropower development will be to support the healthy and rapid growth of hydropower in emerging and developing economies and assist developed countries in implementing relatively robust upgrades to hydropower facilities.

This book introduces technological innovations in hydropower engineering and their contributions to rapid and sustainable hydropower development. It consists of six chapters, that cover the leapfrog development of hydropower in China, hydropower station operation and intelligent management, research on new methods of hydropower utilization, research on the optimized operation of hydropower stations, case studies of hydropower technology innovations, and sustainability of hydropower generation.

China is undoubtedly the fastest, though not the earliest, in hydropower development in the world. As of the end of 2020, China's installed hydropower capacity

reached 370 GW, ranking top in the world for sixteen consecutive years. Chapter 1 "Hydropower Development in China: A Leapfrog Development Secured by Technological Progress of Dam Construction" reviews hydropower development in China, specifically its post-1970s super hydropower projects, and elaborates on the key support of technological progress in dam construction to hydropower projects. In addition, this chapter explains the problems brought about by rapid hydropower development in China and gives in-depth insights and explorations into the country's future hydropower development. These valuable successful experiences can enlighten other countries as to sustainable hydropower development and utilization.

Russia's Volga-Kama Cascade has been in operation for fifty years. In recent years, changes in the global climate and external environment have not only reduced the efficiency of cascade power generation but have also led to a drop in the guaranteed rate of reservoir water supply. In addition, frequent extreme events also threaten the cascade safety and cause ecological disasters. Chapter 2 "Hydropower in Russia: Case Study on Hydrological Management of the Volga-Kama Cascade," using the Volga-Kama Cascade as an example, warns that old hydropower stations should adaptively transform infrastructure in a changing environment and tries to solve the safety problems and rejuvenate old hydropower stations through the adjustment of operation and management methods. This chapter provides an important reference for the study of old hydropower stations in other countries in the world.

Current hydropower generation methods worldwide generally convert the gravitational potential energy of water into electrical energy, but this should not be the whole of hydropower generation. Chapter 3 "Hydro Power Tower (HYPOT)" proposes a technical method of generating electricity from the horizontal flow of water, which can convert the horizontal kinetic energy of seawater into electrical energy. This method inspires us to tap the undiscovered energy of water resources and explore new ways to harness water energy.

During the process of hydropower generation, hydropower stations are subject to changing external environmental factors, including reservoir inflow changes and electricity load fluctuations. Improving the efficiency of hydropower generation under the influence of many uncertain factors has been a persistent challenge to efficient hydropower development and utilization. Chapter 4 "Improved Memetic Algorithm for Economic Load Dispatch in a Large Hydropower Plant" introduces intelligent algorithms into the operation and management of China's Three Gorges Hydropower Station. Practice or experiment shows that the improved memetic algorithm (IMA) can indeed raise the power generation efficiency of hydropower stations. This offers a new technical solution that optimizes the dispatch and operation of large hydropower stations by using intelligent algorithms.

Hydropower development should not compromise ecological environment. Chapter 5 "Innovative Projects and Technology Implementation in the Hydropower Sector" analyzes the eco-environmental impacts of hydropower development and hydropower station construction. It also introduces some technical methods for improving power generation equipment for the purpose of eco-environmental protection, noting that eco-environmental protection is an important issue urgently to be addressed in future hydropower development. These innovations not only protect the species diversity of river ecosystems but also ensure the realization of the expected economic and social benefits of hydropower stations. They embody the significant research on the application of environmental protection technology in hydropower generation.

**V**

consensus.

JQ21029).

Hydropower is the world's largest clean energy that has realized commercial development on a large scale, making an important contribution to cutting carbon emissions. Chapter 6 "Hydropower and Sustainability" examines the promotion and restraint of global climate change, efficient hydropower development and utilization, and energy structure adjustment. It also highlights that the concept of sustainability should be implemented in all stages of planning, construction, and operation. It is gratifying that sustainability has gradually become a global

This book shares the latest progress in scientific research on hydropower and uses some practical cases to inspire innovative ideas for future hydropower research. This book received support from the Beijing Natural Science Foundation (Grant number:

China Institute of Water Resources and Hydropower Research,

Nanjing Vocational College of Information Technology,

Faculty of Network and Communication,

SANY Construction Technology Co., Ltd,

Architectural Research Institute,

**Dr. Yizi Shang** Professor,

Beijing, China

**Dr. Ling Shang** Professor,

Nanjing, China

Beijing, China

**Xiaofei Li** Professor, Hydropower is the world's largest clean energy that has realized commercial development on a large scale, making an important contribution to cutting carbon emissions. Chapter 6 "Hydropower and Sustainability" examines the promotion and restraint of global climate change, efficient hydropower development and utilization, and energy structure adjustment. It also highlights that the concept of sustainability should be implemented in all stages of planning, construction, and operation. It is gratifying that sustainability has gradually become a global consensus.

This book shares the latest progress in scientific research on hydropower and uses some practical cases to inspire innovative ideas for future hydropower research. This book received support from the Beijing Natural Science Foundation (Grant number: JQ21029).

> **Dr. Yizi Shang** Professor, China Institute of Water Resources and Hydropower Research, Beijing, China

> > **Dr. Ling Shang** Professor, Faculty of Network and Communication, Nanjing Vocational College of Information Technology, Nanjing, China

#### **Xiaofei Li**

Professor, Architectural Research Institute, SANY Construction Technology Co., Ltd, Beijing, China

Section 1

## Hydropower Construction and Renewal

#### **Chapter 1**

## Hydropower Development in China: A Leapfrog Development Secured by Technological Progress of Dam Construction

*Yizi Shang, Xiaofei Li and Ling Shang*

### **Abstract**

It has been over 110 years since China's first hydropower station, Shilongba Hydropower Station, was built in 1910. With the support of advanced dam construction technology, the Chinese installed capacity keeps rising rapid growth, hitting around 356 GW nationwide by the end of 2019, and the annual electricity production exceeds 10,000 TWh. At present, China contributes to 25% of global installed hydropower capacity, ranking first in the world for 20 consecutive years since 2001 and surpassing the combined of the 4 countries ranking second to fifth. This paper reviews China's progress in the context of global hydropower development and examines the role of technological advance in supporting China's hydropower projects, especially dam construction technology. China is currently actively promoting the "integration of wind, solar, hydro, and coal power generation and energy storage" and building a smart grid of multi-energy complementary power generation. New technologies and new concepts are expected to continue to lead the world's hydropower development trends.

**Keywords:** China, hydropower, super hydropower project, installed hydropower capacity, dam construction technology, high dam and large reservoir

#### **1. Introduction**

Hydropower is a clean and renewable energy source among conventional energy sources and has the advantages of low operating cost, simple electromechanical equipment, and operational flexibility [1–5]. Hydropower development has thus emerged as a priority option in most developed countries [6–8]. The utilization rate of hydropower resources in developed countries such as France and Switzerland already hit 97% in the late 1980s. In developing countries, the process of water resource development was slow in the past with a low degree of hydropower development due to political, economic, and other reasons. There has been an evidently rapid increase in the pace and rate of hydropower development and utilization in the recent four decades, especially since the mid-1980s. By the end of 2020, the total installed hydropower capacity in the world has reached 1330 GW, and the installed hydropower capacity in 2020 will increase by 1.6%. The global hydropower generation accounts for 16% of the total global power generation, which is lower

than coal-fired power generation and gas-fired power generation, ranking third in the world. Among them, East Asia and the Pacific have the most hydropower generation, accounting for 37.6% of the global total. Major contributors to the added installed capacity are China, Laos, Pakistan in Asia, Brazil in South America, Angola, Uganda, and Ethiopia in Africa, and Turkey in Europe.

Dam is the principal structure for hydropower generation, so the number of dams speaks for the activity level of hydropower development in a country. A large dam is defined by the International Commission on Large Dams (ICOLD) as any dam above 15 m in height (measured from the lowest point of foundation to top of dam) or any dam between 10 m and 15 m in height impounding more than 3 million m3 . According to this definition, there were 58,713 large dams worldwide in 2020. China embraces 23,841 large dams, the most among all countries and more than the combined of the following United States (9263), India (4407), and Japan (3130) [9]. It ranks the world's first with a share of more than 40%. In fact, in addition to storing water for power generation, dams can alter natural runoff through reservoir regulation to render functions such as water supply from upstream reservoirs, downstream navigation, and river ecological flow maintenance. This helps alleviate the plague associated with flood, drought, electricity shortage, and water environmental degradation. In particular, hydropower development avoids greenhouse gas (GHG) emissions of thermal power generation. In view of this, the United States has incorporated hydropower in many targets of the 17 Sustainable Development Goals (SDGs) published in September 2015 [10]. More than 100 countries have so far made it clear that they will continue to build dams and vigorous develop hydropower. It is estimated that by 2035, global installed hydropower capacity will add by about 480 GW to reach 1750 GW, with annual electricity generation of 6100 TWh and hydropower exploitation rate of 38.6%; and by 2050, global installed hydropower capacity will further grow by 300 GW to reach 2050 GW.

China has set an example for global hydropower development. At the end of 2019, China's installed hydropower capacity hit 356 GW with an electricity output of 1300 TWh, accounting for 27.2% and 30.8% of the global total, respectively (**Table 1**). Such a scale is more than three times that of the United States, and larger than the combined of countries ranking second to fifth. China has grown into a veritable hydroelectricity powerhouse based on many super large dams and reservoirs. Next, China's course and


**Table 1.** *Share of hydropower in China's electricity generation and global hydropower generation.* *Hydropower Development in China: A Leapfrog Development Secured by Technological Progress… DOI: http://dx.doi.org/10.5772/intechopen.103902*

achievements in hydropower development will be reviewed, and potential challenges to China's sustainable hydropower development will be analyzed [11].

### **2. China's course of hydropower development**

It has been completely 110 years since China's first hydropower station, Shilongba Hydropower Station, was constructed in 1910 [12–16]. At of the end of 2019, there were 46,758 hydropower stations nationwide, with a total installed capacity of 332.89 GW. Among them, 22,190 above the designated size provide 327.3 GW and 24,568 below the designated size provide 5.59 GW. Besides, 11 of the world's top 20 hydropower stations are located in China (**Table 2**), and all the super hydropower stations built after 1990 come from China without exception.


**Table 2.** *World's top 20 hydropower stations.*

Those Chinese hydropower stations are at the forefront of the world in terms of technology, representing important milestones in China and even the World's hydropower development. **Figure 1** shows the time points of project construction for China's super hydropower stations and their locations in China are as shown in **Figure 2**.

Shilongba Hydropower Station, the first hydropower station in China, was constructed in 1910 and commissioned in 1912. Its installed capacity was 480 kW upon completion and rose to 360 MW in 1949 when New China was founded. Sanmenxia Hydropower Station, the first large-scale hydropower station built in New China, started construction in April 1957 and operation in April 1961, with an installed capacity of 1160 MW. The multi-year average annual output stands at 6 TWh. It contains a concrete gravity dam with a maximum height of 106 m.

Xin'anjiang Hydropower Station was built at the same time as Sanmenxia Hydropower Station and officially put into operation 1 year earlier. This concrete gravity dam, 105 m tall with a crest length of 466.5 m, enables an installed capacity of 662.5 MW, based on 40,000 tons of metal structures and electromechanical equipment, after 5.8592 million m3 of earth was moved and 1.755 million m3 of

**Figure 1.**

*Time points of project construction for China's super hydropower stations.*

**Figure 2.** *Location map of China's super hydropower projects stations.*

#### *Hydropower Development in China: A Leapfrog Development Secured by Technological Progress… DOI: http://dx.doi.org/10.5772/intechopen.103902*

concrete poured. Xin'anjiang is a milestone in China's hydropower development that marks China has become able to independently design and construct large-scale hydropower stations and manufacture hydropower equipment.

Gezhouba Hydropower Station is the world's largest runoff hydropower station. The construction of the Gezhouba Water Control Project spanned from December 1970 to late 1988, with Phase I completed in 1981 and Phase II starting in 1982. The project consists of ship locks, power stations, spillway sluices, scouring sluices, and auxiliary dams. The dam is a gate dam with a maximum height of 47 m. Two riverbed power stations are located in Erjiang and Dajiang. The former has an installed capacity of 965 MW sourced from two sets of 170 MW generating units and five sets of 125 MW generating units. The latter is equipped with 14 sets of 125-MW hydropower generator units to form an installed capacity of 1750 MW. They make Gezhouba's installed capacity total 2715 MW. The 170 MW generating units of the Erjiang Power Station have a turbine diameter of 11.3 m and a stator outer diameter of 17.6 m.

Ertan Hydropower Station is China's largest power station built and commissioned in the twentieth century. The construction began in September 1991 and ended in 2000, and the first generating unit started operation in July 1998. Ertan Hydropower Station is located at the junction of Yanbian and Miyi counties, Panzhihua City, southwest border of Sichuan Province, China. Ertan Dam, with a maximum height of 240 m, sits on the lower Yalong River, 33 km away from the intersection of the Yalong River and the Jinsha River and 46 km from Panzhihua City. Ertan is the first of cascade hydropower stations developed in the Yalong River Hydropower Base, with Guandi in the upstream and Tongzilin in the downstream. Given a normal pool level of 1200 m above sea level, the reservoir impounds 5.8 km3 of water, including a regulated storage capacity of 3.37 km3 . The installed capacity totals 3.3 GW with a guaranteed output of 1 GW, and the annual electricity production averages 17 TWh. The project involving 28.6 billion yuan in investment renders comprehensive benefits in addition to power generation.

The Three Gorges Hydropower Station is the world's largest hydropower station and China's largest construction project. It secures an installed capacity of 22.4 GW with an average annual output of 90 TWh by installing 32 sets of 700-MW generating units. The construction started in 1994 and was officially finished in 2006 [17]. The concrete gravity dam, the world's largest of its kind, is 2335 m long, 115 m wide at the bottom and 40 m wide at the top, and 185 m above sea level, with normal storage level of 175 m. It can withstand floods so severe they come only once in 10,000 years owning to the designed maximum outflow of 100,000 m3 per second. The whole project moved about 134 million m3 of earth and stone and used about 28 million m3 of concrete and 593,000 tons of steel. The reservoir is over 600 km in length and 1.1 km in width on average, making a surface area of 1084 km2 . It impounds 39.3 billion m3 of water, including 22.15 billion m3 for flood control in a seasonal manner. Totally, 32 sets of 700-MW generating units are deployed on the back of the dam, with 14 sets on the left bank, 12 sets on the right bank, and 6 sets underground, and in addition two sets of 50-kW power supply units form an installed capacity of 22.5 GW, ranking second in the world and far exceeding that of Brazil's Itaipu Hydropower Station. By 24 o'clock, December 31, 2014, the Three Gorges Hydropower Station generated 98.8 TWh of electricity throughout the year, a new world record that secures its first position in terms of annual output. This is equivalent to a reduction of nearly 100 million tons of carbon dioxide (CO2) emissions from over 49 million tons of raw coal consumption.

Longtan Hydropower Station started construction on July 1, 2001 and was completed and commissioned at the end of 2009. With a designed storage level of 400 m, the 216.5 m high and 836 m long dam has a storage capacity of 27.3 billion m3 , an installed capacity of 6.3 GW, and an annual output of 18.7 TWh. This dam sets three new world records: the highest roller-compacted concrete (RCC) dam (with a maximum height of 216.5 m, a crest length of 832 m, and a concrete volume of 7.36 million m3 ); the largest underground workshop (385 m long, 28.5 m wide, and 74.4 m high); and the tallest ship lift system (with a full length of over 1800 m and a maximum lifting height of 156 m by two steps).

Xiaowan Hydropower Station is built primarily for power generation but also performs functions in flood control, irrigation, and water transportation. With a maximum height of 294.5 m, the world's tallest arch dam also ranks first in key indicators of arch dam construction such as peak ground acceleration, crest length, and water thrust. Construction started on January 1, 2002. River closure was achieved on October 25, 2004, a year ahead of schedule, and concrete pouring for the first dam warehouse began on December 12, 2005. The diversion tunnel was closed for water storage on December 16, 2008. Pouring and capping across the board was completed on March 8, 2010, marking the birth of the world's tallest 300-m-level hyperbolic arch dam. All the six generating units with a combined capacity of 4.2 GW were commissioned on August 22, 2010. Xiaowan Reservoir, the first reservoir of cascade power stations, impounds about 15 billion m3 of water, including nearly 10 billion m3 for multi-year regulation. The power station is equipped with six mixed-flow generators with a unit capacity of 700 MW and thus forms a total installed capacity of 4200 MW with a guaranteed output of 1854 MW. The average annual electricity production reaches 19.06 TWh.

Xiangjiaba Hydropower Station is a super dam with irrigation function, equipped with the world's largest ship lift system. It is only 1500 m away from Shuifu City, located on the lower Jinsha River at the junction of Shuifu City, Yunnan Province and Xuzhou District, Yibin City, Sichuan Province. The construction was formally kicked off in November 2006, and the station was fully put into operation in July 2014. The installed capacity reaches 7.75 GW with an average annual output of 30.7 TWh, including eight sets of 800-MW rectangular turbines and three sets of 450-MW large turbines.

The core-wall rockfill dam of Nuozhadu Hydropower Station is a classic case of China's successful application of gravelly clay core wall to effectively improve the strength of earth-rock dams. It is of great significance as the first successful case. The construction started in January 2006 and ended after final acceptance in May 2016, with the first generating units put into operation in August 2012. The normal storage level of the reservoir is 812 m and the maximum height of the dam is 261.5 m, ranking third in the world and first in China among similar dams. The open spillway is 1445 m long and 151.5 m wide, the largest in Asia. Flood discharge can reach a magnitude of 55.86 GW with a maximum flow rate of 52 m per second, ranking first in the world in both terms. The stratified water intake scheme adopted by Nuozhadu Hydropower Station created a precedent for environmentally friendly design of hydropower generation in China. The project involving an investment of about 61.1 billion yuan realizes an average annual electricity production of 23.912 TWh based on 4088 utilization hours, which is equivalent to saving 9.56 million tons of coal equivalent and reducing CO2 emissions by 18.77 million tons each year.

Construction of Wudongde Hydropower Station was kicked off in 2015. Concrete was poured for dam construction in 2017. The first generating units were commissioned in June 2020, and all the generating units were officially put into operation in June 2021. A concrete hyperbolic arch dam with a crest elevation of 988 m, a maximum height of 270 m, and a base thickness of 51 m is used as the water-retaining structure. The thickness to height ratio of only 0.19 makes it the world's thinnest 300-m-level super high dam. Wudongde Dam is also the world's first super high arch dam poured with low-heat cement concrete. Twelve generating units with a unit

#### *Hydropower Development in China: A Leapfrog Development Secured by Technological Progress… DOI: http://dx.doi.org/10.5772/intechopen.103902*

capacity of 850 MW have been installed in the power station, making a total of 1.02 GW, the fourth largest in China and the seventh largest in the world.

Xiluodu Hydropower Station focuses on power generation but also contributes to flood control, sand retention, improvement of upstream shipping conditions, and cascade compensation for downstream power stations. It is located on the Jinsha River at the junction of Sichuan and Yunnan. The construction started in June 2004 and fully ended in 2015. A total of 18 sets of 770-MW generating units have been installed, forming an installed capacity of 13.86 GW that supports an average annual output of 57.1 TWh. Flood discharge is a major highlight of Xiluodu Dam, with the flow and power of discharge far exceeding the highest level of arch dams in the world. In European and American countries that have led the world in dam construction, arch dams generally do not have drainage holes out of consideration of stability, such as the famous Hoover Dam. In contrast, a large number of holes are opened in the Xiluodu Dam when the spillway tunnels on both sides of the dam are not enough to discharge all the floods. The Xiluodu Hydropower Station project has the characteristics of narrow river valley, high arch dam, huge volume of discharge, multiple generating units, large cavern complex, and high seismic resistance capacity. It has outperformed existing projects in many key technologies, boasting world's highest level of comprehensive technical difficulty.

Baihetan Hydropower Station is designed primarily for power generation but also plays a role flood control, sand retention, improvement of downstream shipping conditions, and development of navigation in the reservoir area. Equipped with 16 sets of 1-GW Francis turbine generators, Baihetan ranks second in the world in terms of total installed capacity and first in terms of unit installed capacity. The project was officially kicked off in 2013 and is expected to be completed in 2022, with the first group of generating units formally put into operation in July 2021. The underground cavern complex has a total length of 217 km, the largest in the world. For the first time, the power station uses all Chinese-made GW-level turbine generators. This is another historic leap for China's major hydropower equipment after the localization of generating units in the Three Gorges Hydropower Station and 800-MW generating units in Xiangjiaba Hydropower Station.

#### **3. Super technologies underpinning super projects**

Taking into account the historical background of hydropower development, China's super hydropower projects are underpinned by its unique super dam construction technologies, as shown in **Figure 3**.

Since the founding of New China in 1949, substantial progress has been made in the construction of gravity dams [18–21], arch dams [21–24], and earth-rock dams [25–27].

**Figure 3.** *China's super hydropower stations by world indicators.*

Such advancement of dam construction technologies provides the basic guarantee for China's super hydropower projects.

#### **3.1 Super gravity dams**

Concrete gravity dams with simple structure and clear stress can integrate various spillway combinations to ensure high reliable resistance to flood hazards [28, 29]. They are well adapted to terrain and geological conditions by arranging flexibly various types of power plants. In the early 1930s, the 221-m high Hoover Dam was built on the Colorado River in the United States, marking the arrival of a rapid development period of dam construction. In the 1980s, a group of ultra-high gravity dams (higher than 200 m) embodying the dam construction technology of the twentieth century was commissioned to play an important role in river flow regulation, flood control, power generation, irrigation, and water supply. The 285-m high Grand Dixence Dam built in Switzerland in the early 1960s remains to be the world's tallest concrete gravity dam.

In China, the construction of gravity dams in the modern sense began after the founding of New China. In the 1950s, two slotted gravity dams, namely Xin'anjiang and Gutian-I, were constructed to meet the needs of economic and social development. In the 1960s, another two slotted gravity dams, i.e. Yunfeng and Danjiangkou, and two solid gravity dams, i.e. Liujiaxia and Sanmenxia, were added. Hunanzhen trapezoidal gravity dam was completed in the 1970s and Wujiangdu arch gravity dam in the early 1980s. There were over 20 gravity dams taller than 70 m in the country by the 1980s. In this stage, efforts were made to explore ways to reduce dam engineering volume and save project investment, which makes possible the design and construction of many new and lightweight gravity dams.

Dam construction technology, including concrete gravity dams, made notable progress after the 1980s. Following the gravity dam projects in Shuikou, Geheyan, Wuqiangxi, and Yantan, a number of high gravity dam projects such as the Three Gorges Dam, Longtan, Guangzhao, Jinanqiao, and Xiangjiaba were successively launched at the turn of the century, constantly setting records in terms of dam height and project scale. Longtan Dam on the Hongshui River is currently the highest gravity dam in China, with a designed height of 216.5 m and a concrete volume of 7.5 million m3 . In this stage, the height of concrete gravity dams in China grew from 100 m to 150 m and further to 200 m. The number of solid gravity dams also increased due to construction efficiency improvement because such simple structures are more suitable for mechanized construction. A series of new energy dissipation works were commissioned, solving the problem of high-head and large-flow flood discharge and energy dissipation. In addition, RCC gravity dams tend to gradually replace normal concrete gravity dams. China has technologically reached the international advanced level in the construction of high concrete gravity dams and high RCC gravity dams [30, 31]. The most representative examples are undoubtedly the Three Gorges Dam (normal concrete gravity dam) and Longtan Dam (RCC gravity dam).

The Three Gorges Dam is the most concrete incorporated gravity dam in the world. The dam with a height of 181 m and a crest length of 2309.47 m uses 16 million m3 of concrete among the project total of 28 million m3 . Two famous dams comparable to the Three Gorges Dam are the 168 m high Great Coulee Dam on the Columbia River in the United States (with a concrete volume of 7.26 million m3 ) and the 162 m high Guri Dam on the Caroni River in Venezuela (with a concrete volume of 6.71 million m3 ). Longtan Dam as RCC gravity dam represents the highest level of RCC dam construction in the world. Built on the Hongshui River, the dam has a designed height of 216.5 m and a concrete volume of 7.5 million m3 . In order to solve the constraints of high temperature and rain and shorten the time *Hydropower Development in China: A Leapfrog Development Secured by Technological Progress… DOI: http://dx.doi.org/10.5772/intechopen.103902*

of dam construction, China developed the world's most advanced technology of RCC construction under special climates. This technology effectively controls the initial setting time of concrete and realizes the quick coverage by improving concrete production and transportation capacity and silo capacity. It is integrated with unique interlayer treatment technology to enable construction in high temperature and rainy conditions. In addition, the pioneering anti-seepage scheme that combines second-grade RCC and distorted concrete also represents the world's highest level.

#### **3.2 Super arch dams**

Arch dams are water-retaining structures curving upstream on the plane, where water thrust is transmitted partially or fully through the arch to the bedrock on both sides of the river valley. The stability of arch dams is largely supported by the reaction of the bedrock of arch side to water pressure, rather than dam weight as in the case of gravity dams. Axial reaction force at the section of arch ring can take advantage of the strength of dam materials. Therefore, arch dams perform well in terms of economy and safety [32–34].

In the 1980s, RCC began to be applied to arch dams. In 1988, the world's first RCC arch dam, Knellpoort, was built in South Africa. In 1993, China completed its RCC gravity arch dam called Puding by using new dam construction technologies. Thereafter, a group of hydropower stations such as Longyangxia, Ertan, Xiaowan, Laxiwa, Jinping-I, and Xiluodu have been gradually put in place. Baihetan Hydropower Station is still under construction, expected to be completed in 2022. Longyangxia Hydropower Station is the first large-scale cascade power station on the upper Yellow River. It consists of barrage dam, waterproof structures, and powerhouse. The dam is 178 m high, 1226 m long (including the 396-m-long main dam), and 23 m wide. The project can not only block all the annual flow of 130,000 m3 from the upper Yellow River but also forms an reservoir with a surface area of 383 m2 and a storage capacity of 24.7 billion m3 .

Ertan Hydropower Station is the largest hydropower station built and commissioned in China in the twentieth century. The 240-m high dam, whose construction took 10 years, was the tallest arch dam in Asia at that time. The double-curvature arch dam, China's tallest dam, ranks third among dams of its kind in the world, topping in terms of crest length and flood discharge capacity. Laxiwa Hydropower Station is the largest hydropower station and clean energy base on the Yellow River. The dam is 250 m high, but only 49 m wide at the bottom. It is deemed as a thin dam as the ratio of width to height is 0.196, lower than the national standard 0.2. Nevertheless, it renders the largest installed capacity and electricity production in the Yellow River Basin, in addition to the highest dam. Xiaowan Dam with a maximum height of 294.5 m is the world's highest arch dam under construction. It outperforms in this category worldwide in key indicators such as peak ground acceleration, crest length, and water thrust.

Jinping-I Hydropower Station contains a double-curvature arch dam with a height of 305 m, the tallest of its kind in the world. Wudongde Hydropower Station features a super high arch dam, the world's thinnest at the 300 m level and the world's first poured with low-heat cement concrete throughout the whole dam.

The concrete double-curvature arch dam at Xiluodu Hydropower Station has a maximum height of 278 m, a crest elevation of 610 m, and an arc length of 698.07 m, which enables it to withstand 15 million tons of water thrust. The arch dam of Baihetan Hydropower Station has a crest elevation of 834 m and a maximum height of 289 m. The arch dam of Laxiwa Hydropower Station is 250 m high at the most.

#### **3.3 Super earth-rock dams**

Earth-rock dams refer in general to water-retaining structures built by dumping and compacting locally available earth, rock, or mixture. Earth dams are made up mostly of earth and gravel, and rockfill dams are made up mostly of gravel, pebbles, and crushed stones. Earth-rock dams as the oldest type of dams contain both two kinds of materials. Modern technology for earth-rock dams has been developed since the 1950s, which enables the construction of several high dams. Earth-rock dams are now among the most widely used and fastest-growing dam types in the world owning to strong adaptability to complex geological conditions, local availability of materials, and small investment [26, 35].

The United States, Canada, and the former Soviet Union has made rapid progress in earth-rock dams since early twentieth century. A number of 200 m–300 m-level high dams have been built, as Oroville (235 m high) in the United States, Boruca (267 m high) in Costa Rica, and Nurek (300 m high) in the former Soviet Union. China has seen rapid development of high earth-rock dams thought it started construction relatively late. It is now at the forefront of the world in terms of the number and height of high earth-rock dams (200 m level) built and under construction. Examples include Tianshengqiao, Xiaolangdi, and Nuozhadu with designed 300-m-level high dams, Shuangjiangkou (314 m high), Rumei (315 m high), and Lianghekou (295 m high). Earth-rock dam construction technology will make a huge breakthrough.

Tianshengqiao Hydropower Project was officially launched in April 1991, realized water diversion on December 25, 1994, and put into operation the first generator in December 1998. The dam has a maximum height of 178 m, a crest length of 1137 m, and a crest width of 12 m. The reservoir submerged 4539 hectares of arable land and relocated 44,300 people. Xiaolangdi Hydropower Project is huge with construction spanning 11 years. It adopts an inclined core-wall rockfill dam with a designed maximum height of 154 m, a crest length of 1667 m, a crest width of 15 m, and a maximum width of 864 m. Upon completion, it inundates an area of 272.3 km2 and controls a drainage area of 69.4 km2 . Earth amounting to 518.500 m3 is used, and 1.2 m thick and 80 m deep, concrete cut wall is built, both setting new records in China.

The earth-rock dam for Nuozhadu Hydropower Station is 261.5 m high, the tallest of its kind in China and the third tallest in the world. It replaces the 160-m high Xiaolangdi Dam to be China's tallest dam by crossing the line of 100 m in height. As the theory, technology, experience, and specifications for dam construction applicable at that time cannot meet the construction requirements, the project systematically proposed, for the first time, a complete set of technologies for super high core-wall rockfill dams, which uses artificial gravel mixed with earth, as well as soft rock for rockfill materials. This encompasses the static and dynamic constitutive model for rockfill materials, the method for measuring hydraulic fracturing and fractures, a complete set of design criteria, and a comprehensive safety evaluation system for super high core-wall rockfill dams. Nuozhadu Hydropower Station has made and applied a number of innovative results with China's independent intellectual property rights, bringing China's rockfill dam construction technology to a new level.

#### **4. Discussion**

Hydropower development at the river basin level contributes to green and harmonious development by way of efficient use of hydropower resources.

#### *Hydropower Development in China: A Leapfrog Development Secured by Technological Progress… DOI: http://dx.doi.org/10.5772/intechopen.103902*

Multi-objective cascade hydropower development was first proposed in Tennessee river basin development plan in 1933. The model was then successively implemented in the rivers of Cumberland, Missouri, Columbia, Colorado, and Arkansas after Tennessee in the United States. At the same time (1931–1934), the former Soviet Union drew up and put into practice the cascade development plan for the Volga River. In the next 40 years, fast progress was made in cascade development of hydropower. Most developed countries highlighted hydropower in energy strategies and exploited the majority of superior hydropower resources. While developed countries moved toward a steady period of hydropower construction in the 1970s, an upsurge with rapid cascade development took place in some Latin American developing countries in the 1960s. In the 28 years from 1958 to 1986, Brazil carried out a series of cascade development projects on the Paraná River and its tributaries, which encompasses 17 cascade power stations with a total storage capacity of 17.922 billion m3 and a total installed capacity of 39.58 GW. This raised its world ranking in hydropower to 5th from 12th in 1950 with a scale of 1.54 GW.

The continuous deployment of hydropower projects not only provides a steady stream of power to ease the pressure on power supply but also drives economic development. However, dam construction along with water conservancy and hydropower projects has aroused some controversies. On the one hand, dams make abundant water available for agricultural irrigation that facilitates people's lives. Flood regulation and control by dams is also very important to largely avoid the loss of life and property. But on the other hand, dams slow down water flow, which easily leads to water pollution. The United States has begun to demolish some early built dams, and many problems have arisen during the demolition process, including the impact on the river basin and on the topography and geology. China has about 98,000 reservoirs and dams, the most among all countries. As this number increases, the impact on river ecosystems has drawn growing social attention. Such impact is manifested in two aspects. First, the ecological environment of rivers is fragmented by cascade development. For instance, there are 11 hydropower stations built and under construction in the 1326-km mainstream section of the middle and lower Jinsha River, and 10 large hydropower stations sitting on the mainstream alone of the 1060-km long Dadu River. Impoundment of these reservoirs and dams has changed the natural runoff and sediment transportation process of rivers, and especially water temperature. Fish migration channels have been blocked, affecting the survival and development of aquatic ecosystems to varying degrees. Second, the minimum ecological flow of rivers cannot be guaranteed. Construction of dams and reservoirs on rivers inevitably sparks conflicts between economic water use for water supply and power generation and ecological water use within rivers. If the relationship between household, production, and ecological water use is not handled well, the excessive emphasis on water storage to secure household and production water supply will often compromise the ecological flow of rivers. For example, there are many small and medium hydropower stations early built on small- and medium-sized rivers in southern China. They typically do not contain spillway facilities to discharge ecological flow and thus are unable to ensure sufficient ecological flow during the dry season. Diversion hydropower stations have even more impact on the ecological flow of rivers. Flow of small- and medium-sized rivers is naturally limited except during the flood season and varies widely between high- and low-flow periods. As a result of water diversion for power generation, flow is frequently deprived of the section between the barrage and the power station, bringing obvious damage to river ecosystems.

The concept of circular economy provides a new path for the development of hydropower. The circular economy has the characteristics of saving resources, protecting the environment, and promoting economic development, which

coincides with the concept of sustainable development of hydropower. Circular economy mainly affects the power industry in two aspects: one is that circular economy can improve the conversion efficiency of energy and reduce the waste of natural resources; pollution of the surrounding environment caused by electromagnetic fields. As a kind of clean energy, hydropower has relatively little pollution to the natural environment but has a great impact on the ecological environment of the river basin. Hydropower stations should not only consider the benefits of power generation, but also comprehensive benefits such as shipping, flood control, and irrigation. How to improve the current operation mode of hydropower station on the basis of circular economy, so as to achieve the state of nature-society virtuous circle, there is still a lot of research space.

After more than 140 years of development, hydropower has received attention in many countries in the world and has become an irreplaceable and important part of today's clean energy. With the increase of the dam's operating time, its hidden problems have gradually emerged. Due to the different geographical environments and policies of different countries, countries have different ways to deal with the problems arising from the construction of new dams and the operation of old dams. However, there are still some problems that have not yet found a good solution, which has become a common problem faced by hydropower construction in the world. China's hydropower construction is at the world's leading level, and its dam construction technology, management, and operation methods are of great reference value for dam construction and for solving problems in dam operation.

#### **5. Conclusion**

In fact, humans have harnessed water for thousands of years. Due to the late invention of electrical technology, it was not until 1878 that the world's first hydropower station was constructed in France. In the next 100 years, hydropower gradually became the second largest source for power generation after thermal power by virtue of low operating cost, simple electromechanical equipment, and operational flexibility. Super hydropower stations born after 1990 are all from China, in contrast to foreign ones built before 1990. In particular, 11 of the world's top 20 super hydropower stations and 4 of world's top 5 hydropower stations are located in China. The Grand Coulee hydropower station from the United States, the oldest in the ranking, was commissioned in 1942 with an initial installed capacity of 1.97 GW, the largest at that time. It was expanded in 1967 and completed in 1980. China's Jinsha River, originating from the Qinghai-Tibet Plateau, renders the strongest power generation capacity secured by four super hydropower stations. This is attributed to large height difference, water abundance, and perfect terrain with towering mountains on both sides.

Along with rapid economic and social development, household and production water use has squeezed the natural runoff of rivers. Therefore, ecological water requirements that guarantee and maintain the stability of river and lake ecosystems are essential to the sustainable development of human society. Ecological flow is related to the life of rivers and lakes and considered an important indicator to express the ecological water requirements of rivers and lakes. Hydropower development imposes huge negative impact on the ecological flow of rivers. While the United States has begun to dismantle some of the dams built in early days, power generation will be the top priority in the future because the use of electricity as an alternative to oil will be multiplied amid the growing trend of substitution. In recent years, hydropower construction is recovering worldwide. Not only China has *Hydropower Development in China: A Leapfrog Development Secured by Technological Progress… DOI: http://dx.doi.org/10.5772/intechopen.103902*

started construction of more than a dozen large-scale power stations at the same time, but also Africa and the Americas are building large-scale power stations.

However, hydropower station construction is an extremely expensive project involving a series of environmental, geological, and ecological issues. Past dam construction plans largely place emphasize on construction and operation phases and pay little attention to potential problems related to demolition and reconstruction. As the vision of ecological civilization has been widely accepted, it is increasingly recognized in recent years that rivers are a vibrant community of life with biological resource attributes such as water quantity, water quality, shoreline, hydropower, and aquatic organisms. Hydropower developers must not only integrate the conservation of river ecosystems as an important task in the planning, design, and construction phases but also assume responsibility for improving the quality and stability of river ecosystems during the operation phase. In this sense, a major research topic of hydropower development is to minimize the adverse impact of dams on the environment through environment-friendly reservoir construction and operation, and meanwhile, to make full use of reservoirs to rebuild the environment toward a sound situation of ecological improvement featuring harmony between man and water.

#### **Acknowledgements**

This work was supported by Beijing Natural Science Foundation of China (Grant No. JQ21029), and besides, the authors would like to thank Mr. Zeyang Zhao from North China University of Water Resources and Electric Power for doing a lot on the collection and collation of the relevant information and data.

#### **Conflict of interest**

The authors declare no conflict of interest.

#### **Author details**

Yizi Shang1 \*, Xiaofei Li2 and Ling Shang3

1 State Key Laboratory of Simulation and Regulation of Water Cycles in River Basins, China Institute of Water Resources and Hydropower Research, Beijing, China

2 SANY Construction Technology Co., Ltd, Beijing, China

3 Nanjing Vocational College of Information Technology, Nanjing, China

\*Address all correspondence to: yzshang@foxmail.com

© 2022 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.

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#### **Chapter 2**

## Hydropower in Russia: Case Study on Hydrological Management of the Volga-Kama Cascade

*Pavel N. Terskii, Galina S. Ermakova and Olga V. Gorelits*

#### **Abstract**

The capacity of hydroelectric power plants (HPPs) in the Russian Federation (RF) exceeds 50 GW. It is about 20% of the total capacity of all power plants in the country. The Volga River basin is the biggest in Europe with the catchment area of 1 360 000 km<sup>2</sup> . It covers the most populated and most industrialized part of the European Russia. The largest cascade of reservoirs in Russia and Europe is the Volga-Kama cascade (VKC) constructed in 1930–1980. It consists of 12 great water reservoirs and HPPs with total capacity about 12 GW. The main peculiarity for the VKC management is the combination of different requirements by various economy sectors: safety, energy, navigation, water needs for domestic and industrial services, agriculture and fishery, recreation and ecological rules. These sectors often make conflicting demands for the VKC operation. The VKC management principle is to balance and satisfy all of them taking into account the changing climate and economical effectiveness. Modern decisions for the VKC management are based on two principles. First is the constant optimization of the whole VKC management rules, taking into account both climate change and the Strategy of the country development. The second is the constant technical modernization of the VKC equipment to achieve the best economical effectiveness and safety for ecosystems and population.

**Keywords:** Volga-Kama cascade, reservoirs, hydroelectric power plants, water resource management, water budget and regime, efficient operating, climate change

#### **1. Introduction**

Hydroelectric power plants (HPP) produce 16–17% of all electricity capacity in Russia. Currently in Russia there are [1]:


Company "RusHydro" is one of the largest power generating companies in Russia. It is the leader in the generation based on renewable sources. "RusHydro" develops power generation based on the energy of water flow, sunshine radiation, wind power and geothermal energy [2]. There are several cascaded reservoirs constructed on the Great Russian Rivers – Angara and Yenisei cascade, Zeya and Bureya cascade, Lower Don cascade, Moscow river system cascade etc. The largest cascade of reservoirs in Russia is located on the rivers Volga and Kama.

The Volga River basin is the largest in Europe with catchment area about 1 360 000 km2 (including Kama River basin). The total Volga River basin area is 40% of European territory of the Russia. The basin covers most populated and most industrialized part of European territory of Russia. It is populated with 58 mln. There are 7 cities with more than 1 mln population.

The Volga River is the longest river in Europe, its length from the source to the Caspian Sea is 3530 km. There are hundreds of tributaries along the main Volga River, the largest are Oka River (right tributary) and Kama River (left tributary). The Lower Volga region, including the unique ecosystems of Volga-Akhtuba Floodplain and Volga Delta – is the only natural part of the Volga River that is not affected by the backwater of anthropogenic HPPs dams. Annual average Volga water runoff (1881–2020) at the terminal gauging station "Volgograd" is 253 km3 . Maximum year runoff – 389 km3 (1926), minimum year runoff – 160 km3 (1975).

The largest cascade of reservoirs in Russia is the Volga-Kama cascade (VKC) constructed in 1930–1970s. The main reservoirs of VKC were fully completed by the beginning of 1960s. The VKC is the largest energy and transportation water system in the Europe (**Figure 1**).

**Figure 1.** *Volga river drainage basin and VKC reservoirs.*

#### *Hydropower in Russia: Case Study on Hydrological Management of the Volga-Kama Cascade DOI: http://dx.doi.org/10.5772/intechopen.100427*

Nowadays VKC includes 12 great water reservoirs with 12 Hydroelectric Power Plants (HPPs) and several small reservoirs without HPPs (**Figure 1**). Active storage of the VKC reservoirs is 80 km3 , total VKC storage – 175 km3 . Total design capacity of VKC HPPs is about 12 GW, actual capacity now is about 10,5 GW, annual hydropower generation – 35-40 billion KWh [2]. The HPPs of the VKC covering the peak part of the electricity consumption schedule are the backbone of the Unified Energy System of Russia, because it can increase electricity generation faster than other energy sources, such as nuclear or thermal power plants. The Volzhskaya HPP in the city of Volgograd – the downstream object of the VKC – is the largest HPP in Europe, with a total installed capacity of 2671 MW (**Figure 2**).

Construction of the Volga-Kama cascade was released as part of the great project "Big Volga", which was developed in the Soviet Union in the beginning of 1930s and was implemented from 1935 to 1960s. The "Big Volga" project assumed simultaneous solution of several serious problems of the European part of Russia economic development in 1930s: water transport, cheap energy, industrial and domestic water supply, agriculture and irrigation of arid regions, fisheries. There were several main purposes of the VKC construction. First was to create the transit waterway with guaranteed navigable depth about 4,5 m throughout the Volga River from upstream to the Caspian Sea, which connects the main industrial centers and raw materials regions. Second was to obtain huge amount of cheap energy. Third was the irrigation and industrial water supply.

Construction of three reservoirs in the upper stream of Volga river – Ivankovo, Uglich and Rybinsk – was the first step of the "Big Volga" project. It was started in 1930s - Ivankovo reservoir was built in 1937, but then the construction was suspended due to the Second World War. Uglich and Rybinsk reservoirs were completed only in 1955. The next step – creation of the Gorky, Kuybyshev, Kama and Volgograd (former Stalingrad) reservoirs – was fully completed by 1965 (**Figure 3**).

**Figure 2.** *Volzhskaya HPP in the city of Volgograd.*

**Figure 3.** *Uglich HPP (a) and Kama HPP (b).*

Votkinsk, Saratov, Lower Kama and Cheboksary reservoirs were built on the last stage of the construction.

Total head of Volga River from the source to the mouth – Caspian Sea – is about 256 meters. Total head of Volga River between the headwater of Ivankovo reservoir and tailwater of Volgograd reservoir is 135 meters, so it gives 8400 MW total actual capacity of the Volga hydroelectric power plants. Total head of Kama River between the headwater of Kama reservoir and tailwater of Lower Kama reservoir is 55 meters, so it gives 2150 MW total actual capacity of Kama hydroelectric power plants. The main characteristics of the VKC are shown in the **Table 1**, **Figure 4**.

**Figure 5** demonstrates spatial heterogeneity of local catchment areas and local water inflow to reservoirs of the VKC. The 75% inflow is generated inside the biggest local catchments of Cheboksary, Kama, Lower Kama and Kuybyshev Reservoirs. Contribution of other reservoirs is less than 10% (for each of them).


*F - fisheries;*

*I - irrigation;*

*R - recreation.*

**Table 1.** *Main characteristics of the VKC [1, 3].*

*Hydropower in Russia: Case Study on Hydrological Management of the Volga-Kama Cascade DOI: http://dx.doi.org/10.5772/intechopen.100427*

**Figure 4.** *VKC water surface profiles (based on materials [1, 4]).*

**Figure 5.** *Local catchments of the VKC reservoirs (a) and contribution of the local inflow to the VKC total inflow, % (b).*

#### **2. Natural and manmade changes in the water budget and regime**

Volga River basin and all reservoirs of the VKC are located on the southern slope of the East European Plain. The basin has some unique geographic features. From Middle Ages till present days Volga River system with its hundreds tributaries were located within the borders of one state – Russia. This feature distinguishes the Volga River basin from the basins of major European rivers and determines the features of its economical and cultural development. For example, Danube River basin partially covers the territories of 19 European countries, Rhine River basin – 6 countries, basins of the Dnieper, Daugava, Neman, Maas, Oder Rivers – partially covers the territories of 3 countries.

Volga River runs into the largest inland water body in the World – into the Caspian Sea. This unique feature defines a unique ecosystem of the river basin and the Sea and allows us to investigate the hydrological regime of this huge ecosystem *Hydropower in Russia: Case Study on Hydrological Management of the Volga-Kama Cascade DOI: http://dx.doi.org/10.5772/intechopen.100427*

in the framework of single hydrological cycle, which is determined by climatic changes, the anthropogenic influence and the VKC operation.

Climate changes in the Volga River basin – is the most important challenge of the last quarter of XX Century and the beginning of XXI Century. Against the background of a general increase in air temperature these increase in the European territory of Russia reached 0.5°C over 10 years. The main increase of temperature occurred in the winter period of the year, together with increase of humidity years [5, 6].

These climate changes significantly affect the water inflow to VKC. The temperature and humidity changes are resulted in the total annual inflow increase to VKC by 13% in last 40 years. Mean annual inflow to VKC for the period 1946–1977 is 248 km3 , while for the period 1978–2020 it is about 280 km3 (**Figure 6**) [7, 8]. But between the sub-periods 1978–1995 and 1996–2020 there are significant positive changes in Evaporative Index end Dryness Index in the Volga basin, which caused a decrease in the inflow to the cascade from 295 km3 (1978–1995) to 268 km3 (1996– 2020). The nowadays sub-period of 1996–2020 shows decreases in local inflow to VKC reservoirs and consequently decreases in water runoff through the Volzhskaya HPP into the unique ecosystems of the Lower Volga wetlands in the past couple of decades. Such climate-induced changes in the parameters of hydrological regime could explain only a part of the observed runoff decreases and changes in evaporative loss. The remaining, unexplained part is most likely related to the considerable changes in land-use at the agricultural regions of the Volga River catchment and other anthropogenic pressures [9].

Although climate changes much more strongly affects the seasonal inflow redistribution during last 40 years. The main feature of seasonal redistribution is alignment of intra annual unevenness of water inflow: great increase (about 63%) of winter water inflow because of warm and humid winters, increase (33%) of summer-autumn water inflow and slight decrease (2%) of spring flood period water inflow (**Figure 7**).

Significant intra annual water inflow redistribution caused the changes in the VKC operation. The winter water runoff and winter generation increased strongly.

**Figure 6.** *Total annual inflow to the VKC (based on materials [7, 8]).*

**Figure 7.** *Redistribution of the intra annual water inflow (based on materials [7, 8]).*

#### **3. Management principles**

All of the VKC reservoirs are integrated-purpose water bodies. The complexity of the reservoir operation problem depends on purposes compatibility. If the purposes are more compatible - less effort is needed for coordination [10]. The main peculiarity for the VKC management is the combination of many requirements of various sectors of the economy: technical safety, energy, navigation, water needs for domestic and industrial services, agriculture and irrigation, fishery, recreation and ecological requirements. These sectors usually make conflicting demands to the VKC operation. The VKC management principle is to balance water users and consumers' demands and satisfy all of them taking into account the current conditions of a changing climate and the changed regime of local inflow to the VKC reservoirs and resulting total runoff downstream the cascade to the Lower Volga and Caspian Sea [5, 11].

There are several types of water consumption: domestic water supply, industrial and agricultural water consumption, irrigation. The largest water consumers are concentrated in the certain places associated with large cities. However, smaller ones are widely distributed along the lateral tributaries.

The important water users are hydropower engineering, water transport, fishery and recreation. To meet the requirements of these users, it is necessary to fill the reservoirs and not to exceed regulated water levels during the spring flood period. Reservoirs of the VKC serve to moderate both the flood risk and risk of summer droughts.

The reservoir operation is the water resource management, which regulates the water regime in interannual, seasonal, weekly and daily scales (sub-daily regulation also exists). The methods of reservoir operation are divided into operating curve method and rational operation [12]. Operating curve method makes possible the reservoirs functioning without detailed hydrological information and without enough range of hydrological forecast. The regulation procedures are being made depending on the operating curve, which represents the linkage between the day-by-day upstream water level and the discharge through the dam. The operating curve preparation is the goal of the water regime calculations based on stochastic programming for the optimal discharge planning.

*Hydropower in Russia: Case Study on Hydrological Management of the Volga-Kama Cascade DOI: http://dx.doi.org/10.5772/intechopen.100427*

Nevertheless, the operating curve cannot provide the reservoir regulation in case of emergency hydrological situations and in case of rapid change in the water management plans. Rational reservoir regulation begins to be implemented by applying the multiple forecast calculations of local inflow. In case of moderate situation (without rapid change in inflow forecast), rational regulation does not require excluding the operating curve from regulation. Rational regulation is prior to the operating curve method in case of complicated hydrological situation and changing inflow forecast.

This combination of the VKC regulation methods is based on the assessment of the forecast and hydrological situation (forecast-situational regulation). This kind of regulation is applied for different water seasons – spring and rain floods and flashes, summer and winter low water periods.

It begins with the hydrological forecast of the VKC distributed lateral inflow, compared to the water consumption plans and initial water level conditions for all reservoirs. Then different scenarios between the lowest and the highest water inflow are calculated and these results are used for the operation. If the real inflow begins to differ from the chosen plan, the scenario is being changed to fit the real inflow.

The main operating method for the low-water season is the compensatory regulation. Upstream reservoir storage gives the guaranteed discharge to provide the uninterrupted discharge through the downstream reservoir. The capacity of the VKC in the low-water season depends on the cascade regulation in the spring flood season. There are three main optimization tasks to operate the reservoirs: to choose the most rational regime of the spring flood transit, to choose the regime of water use during the low-water season or period, to optimize the cascade regulation using the operating curves. There is special software to meet this challenge. WATER RESOURCES and CASCADE systems serve the goal of choosing the VKC operating regime. ECOMAG is the distributed hydrological model with integrated operating curve method. It is used to calculate the distributed water inflow to the VKC [13, 14].

#### **4. Problems and modern decisions**

Multiple purposes of the VKC use leads to several types of conflicts between main users. According to [9] these conflicts are: conflicts in space, conflicts in time, conflicts in discharge. These conflicts have to be resolved in the most effective way by the reservoirs operation.

The main problems of the VKC operation are as follows:


To solve these problems the strategic and tactical planning has to be used. Strategic planning attended to solve the long term goal choice problem, i.e., the preferable realizable set of the values of water availability for its users and the key parameters of the VKC functioning. Tactical (annual) planning with decisions made at the level of Interdepartmental Working Group with the aim to take into account the specific hydrological and water-management conditions of the current year. These goals can be achieved by constructing the wide range of attainable probabilities. The final compromised decision is based on Pareto boundary for these multiple attainable probabilities by the consolidated negotiations between the main water users [14].

Modern decisions for the VKC management are based on two branches. First is the constant scientific-based optimization of the whole VKC management rules, taking into account both climate change and the Strategy of the country development.

One of the optimization perspectives is the change in the VKC operation by using the variable (against planned one) forecast-based water release in the spring flood period in the highest and lowest zones of inflow probability curve. It looks possible with help of long-range hydrological forecast (about 1 month). In case of estimated high water inflow reservoirs should release additional water volume. In case of low water forecast – reservoirs should decrease water discharge. It allows to decrease subsequent water volume, needed to fill reservoirs, and to increase water capacity for the Lower Volga supply. This kind of operation is mentioned for the pre-flood period in the Rules [14], but real methodology and legislative basis are not developed yet. Moreover it will require the revisions of the Rules.

The second is the technical modernization of the VKC to achieve the best effectiveness and safety. It should provide the required energy supply based on lower winter discharge. Filling the Cheboksary and Lower-Kama reservoirs up to projected levels can provide the ability to operate the effective and total storage of VKC in more efficient way [15].

#### **5. Conclusions**

The main environmental effect of river regulation in general and hydropower reservoir operations in particular is the alteration of the stream flow regime at various time scales, including seasonal, monthly, daily and sometimes hourly. This effect is fully manifested in the only natural area of VKC - the Lower Volga, including the unique ecosystem of Volga-Akhtuba floodplain, where the UNESCO Biosphere Reserve is located, and Volga Delta. The change in the spring flood regime led to a serious change in the landscapes and water bodies of the whole Lower Volga and the steppe formation of the northern part of Volga-Akhtuba floodplain. This negatively affected the state of the entire ecosystem of the Lower Volga, including Volga Delta and Northern part of the Caspian Sea [11].

The main results of VKC operation to the beginning of XXI Century are as follows:


*Hydropower in Russia: Case Study on Hydrological Management of the Volga-Kama Cascade DOI: http://dx.doi.org/10.5772/intechopen.100427*


VKC management and operation improvement is the governmental goal of whole institutes. Authors only may suggest some general vectors to solve main problems of the VKC operation. First - to increase the density of hydrological gauging network in the VKC catchment to have the basis for improvement of the stochastic description of the water inflow. Second - to develop more effective medium and long range hydrological forecasts. Because of problem of water inter annual and long-term temporal distribution these improved forecasting methods should support the decreasing of water losses during flood periods and save it for the deficit periods by dynamical storing it in the VKC. Finally - to develop the legislative basis for new implementation of variable operating rules of water management of the VKC.

#### **Acknowledgements**

The chapter is based on materials and data collected under the State contract #10-GK/FCP-2013 "Water management complex of the Russian Federation in 2012-2020" realized by Zubov State Oceanographic Institute (SOI) with significant contribution of Russian Academy of Science Water Problem Institute (WPI), Kostyakov All-Russian Research Institute for Hydraulic Engieneering and Land Reclamation (VNIIGIM), Caspian Research Institute for fishery, Hydrometeorological Research Center of Russian Federation (Hydrometcenter).

#### **Conflict of interest**

The authors declare no conflict of interest.

#### **Notes/thanks/other declarations**

Authors are thankful to members of Automated Methods lab in SOI and personally to Igor Zemlyanov (PhD, head for the lab, vice director of the Institute) for the overwhelming support, Aleksander Buber (VNIIGIM), Mikhail Bolgov (WPI) and Vladimir Kryzhov (Hydrometcenter) for consultations.

*Technological Innovations and Advances in Hydropower Engineering*

#### **Author details**

Pavel N. Terskii1 \*, Galina S. Ermakova<sup>2</sup> and Olga V. Gorelits2

1 Faculty of Geography, Lomonosov Moscow State University, Moscow, Russia

2 N.N. Zubov State Oceanographic Institute, Roshydromet, Moscow, Russia

\*Address all correspondence to: pavel\_tersky@mail.ru

© 2021 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.

*Hydropower in Russia: Case Study on Hydrological Management of the Volga-Kama Cascade DOI: http://dx.doi.org/10.5772/intechopen.100427*

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### Section 2
