China - Yangtze Basin Flood Control Project : environmental impact assessment (Vol. 2 of 3)

E-291 VOL. 2 DESCRIPTION OF PROJECT/2000 FOR YANGTZE DYKE STRENGTHENING PROJECT MARCH 2000 Research Institute for Yangtze Water Resources Protection With assistance from: Hunan Water Conservancy & Hydropower Survey & Design Institute Hubei Water Conservancy & Hydropower Survey & Design Institute  YBFCP/EIA FINAL REPORT CHAPTER 2: PROJECT DESCRIPTION CHAPTER 2 PROJECT DESCRIPTION TABLE OF CONTENTS: TEXT 2.1 Project Background 2.1.1 Yangtze River and Flooding 2.1.2 Master Plan for Yangtze Basin Development 2.1.3 Need for YBFCP 2.2 Project Components 2.2.1 Dyke Rehabilitation 2.2.2 Resettlement 2.3 Environmental Protection Measures 2.4 Construction Program 2.4.1 Construction Layouts 2.4.2 Construction Methods for Main Items 2.4.3 Construction Schedule 2.4.4 Summary of Construction Program 2.5 Comparison of Altematives 2.5.1 Non-project Alternative 2.5.2 Other Alternatives Considered 2-.6 Economic Analysis of Project 2.6.1 Introduction 2.6.2 Project Budget 2.6.3 Benefit-Cost Analysis 2.7 Project Management 2.7.1 Introduction 2.7.2 Establishment of Institutions 2.7.3 Project Management 2.7.4 Technical Management 2.7.5 Financial Management 2.8 Summary and Conclusions FIGURES Figure 2.2-1 Project Area Figure 2.2-2 Sub-project in Hubei Figure 2.2-3 Sub-project in Hunan Figure 2.2-4 Typical Resettlement Area in Hunan Figure 2.4-1 Sketch-map of Typical Dyke Section Figure 2.7-1 Sketch-map of Project Management System TABLES Table 2. 1-1 Condition of Dykes Involved in Project Table 2.2-1 Project Components and Protected Area Table 2.2-2 Summaries of the Main Quantities of Work of Project Table 2.2-3 Sunmmary of Property Losses Result from Relocation 2-i  YBFCP/EIA FINAL REPORT CHAPTER 2: PROJECT DESCRIPTION Table 2.4-1 Construction Schedule Table 2.6-1 Summary of Economic Analysis of Project Table 2.8-1 Sunmmaries of Project Characteristics ANNEX A REFERENCES Reference reports and documents 101 "Report on Key Points of Comprehensive Utilization Planning for the Yangtze Basin", CWRC, December, 1988 103 "Recommendation on Yangtze Main Dyke Rehabilitation in Hubei", Hubei Instituie for Survey and Design of Water Conservancy and Electric Power Project, May, 1999 104 "Recommendation on Yangtze Main Dyke Rehabilitation in Hunan", Hunan Institute for survey and design of water conservancy and electric power project, March, 1999 105 "Implementation Program of Yangtze Main Dyke Rehabilitation Project of Hubei Province in Application for Loan from the World Bank (draft)", Hunan Institute for Survey and Design of Water Conservancy and Electric Power Project, June, 1999 106 "Study Report on Feasibility of Rehabilitation of the Yangtze Main Dyke in Hunan" and its attachment, Hubei Institute for Survey and Design of Water Conservancy and Electric Power Project, May, 1999. 107 "Study Report on Feasibility of Rehabilitation of the Yangtze's Main Dyke in Jiangxi" and Its Attachment, "Drawings Book", Jiangxi Institute for Planning and Design of Water Resource Project, May, 1999 111 "Study Report on Feasibility of Rehabilitation of the Yangtze's Jingnan Main Dyke in Hubei", Changjiang Academy, CWRC, December, 1998 123 "Implementation Program for Resettlement of the Yangtze River Dyke Rehabilitation Sub-project in Hunan", Hunan Institute for Survey and Design of Water Conservancy and Electric Power Project, June, 1999 130 "Implementation Program of Yangtze Main Dyke Rehabilitation Project of Hubei Province in Application for Loan from the World Bank", Hunan Institute for Survey and Design of Water Conservancy and Electric Power Project, March, 2000 131 "Resettlement Action Plan of Yangtze Main Dyke Rehabilitation Project of Hubei Province in Application for Loan from the World Bank", Hunan Institute for Survey and Design of Water Conservancy and Electric Power Project, March, 2000 132 "Findings of benefit-cost analysis of project", Mr.Colin Green, the World Bank economic expert, March, 2000 412 "Cost Composition and Calculation Standard for Budget Estimation of Water Resources and Hydropower Development", Ministry of Water Resources of P.R.C., January, 1998 4 13 "Ration for Costs Per working Day of Machines Used in Construction of Water Resources and Hydroelectric Power Project", Ministry of Energy & Ministry of Water Resources of P.R.C., 1991 2-ii  YBFCP/EIA DRAFT FINAL CHAPTER 2: PROJECT DESCRIPTION 2 PROJECT DESCRIPTION 2.1 Project Background The Yangtze River, 6,300 km in length, with its basin covering 1.80 million km2 of acreage, is the biggest river in China. It annually discharges 960 billion m3 of water into the East sea. The Yangtze basin covers the East, Central and Southwest China, with a favorable climate and rich resources. With gross output value of industry and agriculture accounting for about 40% of the Nation's total, the basin is one of the most economically developed and most important regions of China. Flooding is frequent in the Yangtze river basin. Flood disasters are usually widely distributed in the basin. Especially, the 126,000 km2 of plains area in the middle and lower basins frequently suffer from serious flood and waterlog damages as the ground elevations there are commonly several to more than 10 meters lower than the flood water levels. These flood disasters occur with the frequency of once in every ten years. These historical deluges have caused huge losses to people's property and lives, serious damages to the local ecology and environment, which seriously restricts the development of economy. For this reason, flood control has always been the first task for the basin improvement and development. The characteristics of the Yangtze flooding phenomena are rather complicated. The maximum flood peak discharge is not only related to the scope, intensity, moving direction of the rainstorm, but also the timing and distribution of local floods in various parts of the river systems. The regional composition of floods is quite different in different years because of the variation of rainstorm distribution. There are mainly two types of floods that usually cause damages in the basin. Flood of the first type occurred in 1860, 1870 and 1935. These are caused by extra-high rainstorms in some reaches of the mainstream and some tributaries. This type of flood is usually huge in discharge and high in peak level. The second, such as occurred in 1931, 1954 and 1998, is caused by basin-wide rainstorm where floods in the tributaries are similar to that of the mainstream. In order to solve the flood problem in the Yangtze middle and lower reaches, Changjiang (Yangtze) Water Resources Commission (CWRC) of the Ministry of Water Resources of PRC compiled a report, "Summary Report on Comprehensive Utilization Planning for the Yangtze Basin" [Ref.102], in 1990, which was subsequently approved by the State Council. The Report points out that flood control in the middle-and-lower reaches of the Yangtze should follow the principles of considering flood release and storage at the same time. Releasing ranks first because this is beneficial to flood control both in the rivers and the lakes, both the banks, and both the upstream and the downstream. These measures include: properly raising and rehabilitating the bodies of the dykes; hamessing the river channel; planning and constructing diversion areas; and constructing reservoirs on the Yangtze mainstream and its tributaries. In addition, the provinces along the Yangtze, mainly Hunan and Jiangxi, have been carrying a special program for enlarging the diversion capabilities of the "flood storage lakes", such as Dongting Lake and Poyang Lake, and for 2-1  YBFCP/EIA DRAFT FINAL CHAPTER 2: PROJECT DESCRIPTION alleviating flooding damages to some 900,000 "Embankment People", i.e., those people living and farming in area in the Lakes and outside the dykes (between dykes and embankments), which are subject to serious flooding. This program includes provisions for permanent resettlement of some of these peoples and for other temporary resettlement at time of flooding with provision for them to continue farming in the flood-hazard areas at times of no-flooding. After these measures are taken, flood control for the middle and lower reaches can be properly solved, with the Yangtze Three Gorges reservoir playing the role of the backbone, adding the reservoirs, diversion works, river channel improvement and non-engineering flood control measures. In the overall system, dyke construction is one of the most important measures to tackle the flood problem in the Yangtze middle and lower reaches. As shown in Figure 2.1-1, Hubei, and Hunan provinces are located in the Yangtze middle and lower basin. The Yangtze main-stem dykes in the two provinces have existed for thousands of years. For example, the Jingnan main dyke of the sub-project of Hubei was originally constructed about 300 AD. However, these provisions for flood prevention has not been very adequate, although raising and rehabilitation of levees have been implemented several times. Although flood emergency measures were implemented during the 1998 deluge, heavy costs have also been paid. The 1988 deluge revealed that there are many obvious and hidden defects in the bodies and bases of dykes, which need urgent treatment. Just after the 1998 deluge, a series of policies were timely put forward in State Council for needs for flood control improvements learned from the deluge, among which is this project. In order to implement the policy, the State Commission of Planning has put this project into its executive plan, including an application to the World Bank for a loan to support construction of the project. the Government and WB have agreed to reduce the scope of Bank financing. The main changes in Bank financing are as follows: a. Jiangxi province is no longer included; b. Project underwater components, such as cut-off wall, bank protection works, are no longer included because responsibility for these works has been shifted from provincial government to the CWRC (Changjiang Water Resources Commission); c. More dyke sections in Wuhan have been included and some dyke sections in other areas in Hubei province are no longer included, and d. As a result of above changes, World Bank financing participation is reduced from US$300 million to US$ 235 million. 2-2  YBFCPIEIA DRAFI FMNAL CHAPTER 2: PROJECT DESCRIPTION 2.2 Project Components 2.2.1 Dyke Rehabilitation This project area is located in the hinterland of China, involving Hubei, and Hunan provinces as shown in Figure 2.1-1. Totally 30 cities (or counties, townships, embankment areas) are involved. In Hubei sub-area, the involved and project- protected areas include 22 counties (or cities, townships) under the jurisdiction of Wuhan, Jingzhou, Xianning,Ezhou, and Huangshi cities respectively. In Hunan sub- area, the areas include 8 counties (or cities, districts, embankment areas) under the jurisdiction of Huarong, Junshan, Qianlianghu, Yunxi, Linxiang, Yueyang City, Yueyang County, Huanggaihu, respectively. See Table 2.2-1. According to the proposal report and the feasibility reports for the Project, the Project is composed of 5 separate dyke sections on the both banks. The main construction items of the project components are briefly described in Sections 2.2.1.1 and 2.2.1.2 . 2.2.1.1 Sub-project in Hubei (See Figure 2.2-2) This sub-project is composed of following main-stem dyke sections: Jingnan, Wuhan, Huanggang, and Ezhou Bapu. Among these dykes, Jingnan, Wuhan (Wuchang Section), and Bapu are on the south bank, while the rests are on the north bank. This sub-project will involve rehabilitation of 24 segments. The main construction items include bank raising and strengthening, dyke body grouting by prick exploration, seepage interception by concrete wall, filling-up the platforms inside and outside, filling-up ponds to rehabilitate the dyke basis, revetrnent, rehabilitation and reformation of culverts in the dyke body, dyke-top-road pavement, planting for bank slop protection. The dykes to be improved are approximately 280km in length and 49 culverts and pump stations will be reconstructed or strengthened. The work quantities are: earth 55.82 million mi3; concrete of 503thousand mi3; steel bar and rolled steel of 3092 t. 2.2.1.2 Sub-project in Hunan (See Figure 2.2-3) This sub-project involves the dykes of 8 embankment areas of Yueyang City. The main construction items include: bank raising and widening; dyke body grouting by splitting and prick exploration; dyke basis treatment, filling-up pond to consolidate the dyke basis, maintaining and prolonging of buildings in the dyke body, construction of dyke management facilities, equipment and resettlement. The dyke to be rehabilitated is 136 km in length. 1.4 km flood prevention wall and 4.21 km earth dyke will be newly constructed. Some 65 structures (culverts) through the dyke will be rehabilitated or strengthened. 62 sinks and nets will be built for snail control (nets will be placed at the outlets of diversion culverts or gates to collect snails; sinks will be built under the nets to make escaped snails settle). The work quantities are: earth 20.14 million m3; building rock 367 thousand m3; concrete and steel bar reinforced concrete 172 thousand m 3; steel bar and rolled steel 2,353 t. 2-3  YBFCP/EIA DRAFT FINAL CHAPTER 2: PROJECT DESCRIPTION 2.2.2 Resettlement It is proposed to resettle a total of estimated 36,256 people; 1,770,770 m2 houses need to be relocated;3 1404 mu land occupied, of which 1 6050mu are farmland. In Hunan province this involves 52 villages, with a total of approximately 4,460 families and 19,200 resettlers. Majority of the people to be resettled are rural and earn their livelihoods from farm/agricultural incomes. The Resettlement program of the project has been prepared to take into account all socio-economic and environmental impacts to both the resettled population and the host communities. Detailed compensation provisions have been worked out for land acquisition, loss of income form change of livelihood, loss of income during transition, budget provision for resettling people in both agricultural and non- agricultural modes of production as well as encouraging new livelihoods in secondary and tertiary industries. Provisions have been made for providing the resettlers with farm subsidies, tax incentives and other financial and support measures that will allow both the resettlers and the host population to reap benefits from the program. Ii Hunan province, for instance, on completion of resettlement period (2001), there will be an estimated increase of 53% in total net income from land resources and 57% from other secondary and tertiary industries. The resettlement villages will be equipped with adequate housing types and spaces), yard, amenities including water supply, excreta and solid waste management, drainage, power supply, telecommunications, schools and clinics. All resettlement will be carrned out according to the national policies, laws and regulations with cooperation from local authorities. In brief the following measures are to be taken. (a) Compensation will be made in advance to the people to ensure smooth progress of the resettlement program, so the resettlers will be able to adapt as soon as possible to regain their former condition of production and living, and Resettlement villages/townships can be constructed and completed according to the construction schedule. (b) The Local Governments will cooperate for processing programs to assist the resettlers with tax privileges, loans and credit. (c) Resettlement of non-rural people: For resettlement of the non-rural people, the local governments will designate land in the same cities or towns for them to build their new houses. The original facilities for water and electricity supplies and communication will be relocated to the new residential areas by the local relevant departments. Some new facilities will be built. Conveniences for medical care system and schools will also be provided. Livelihood will be re-arranged for those whose income sources of life are affected and some economic compensation be made to them, so they will not lose financially because of their resettlement, including loss of income during the transition period. (d) Resettlement of rural people: The project will occupy rural land including farmland, vegetable land, and forestland, fishing ponds and residential land. For people whose houses need to be relocated, new housing areas will be delineated for them in locations as close as possible to their original areas. For people whose 2-4  YBFCP/EIA DRAFT FINAL CHAPTER 2: PROJECT DESCRIPTION production lands are occupied, land allocation will be made in their village to provide them with proper areas of production land, and economic compensation will be made for them. Economic compensation, privilege credit and technical training will be provided for the resettlers so that they can pursue other production activities, such as tertiary industry or other agricultural and sideline occupation when land resources are limited. (e) Compensation and budget allocation has also been made for rehabilitating the socially and economically weaker sections of the resettled population. Figure 2.2-4shows typical resettlement areas in Hunan Province. Table 2.2-3 gives summary of substance losses incurred from relocation. 2.3 Environmental Protection Measures Aiming at flood control, this project itself is an environmental protection project. It will markedly improve economics and quality of life in the protected area by greatly reducing flooding episodes. Besides the direct environmental benefits, the project will also gain the following additional environmental protection benefits: (a) Water and soil conservation: Forest and turf planting have been included in the project plan. Once the engineering work is finished, planting will begin. More than 500,000 m2 of wave-break forest and 13,300,000 m2 of turf will be planted. The total costs are more than 2million and 45 million yuan, respectively. This will not only benefit dyke protection, but also beautify the landscape and conserve water and soil. (b) Control of snails and schistosomiasis: Killing snail is an effective measure for schistosomiasis control as the snail is the necessary interim host of schistosomiasis. Snail control has been included in the construction program. For example, the sub- project in Hunan has planned to set up sinks and nets at 62 sites for snail control. (c) Improving the production and living conditions of the resettles: Dyke rehabilitation needs to relocate some local residents. A special resettlement program has been made to deal with the resettlement. Refer to literature reference [Ref.123, 124, 125] for details. According to resettlement program, some 30000 people are to be properly resettled. See Chapter 4 for details of other environmental protection measures. 2-5  YBFCP/EIA DRAFr FINAL CHAPTER 2: PROJECT DESCRIPTION 2.4 Construction Program 2.4.1 Construction Layouts Construction of the Project will be characterized by the following points: construction can only be carried out in dry season before the flood period; there are many construction items which are scattered in areas along the dykes, and a wide region will be involved. The construction layouts will be made according to the local conditions and the principles of beneficial to production, convenient for living, easy for management, safe and reliable, economic and reasonable" [Ref. 107]. The construction sites will include a main work construction area, construction material exploitation area, and management center. The construction accesses will include waterways and highways. Waterways in the Yangtze River, Dongting Lake and many types of docks along them can be used. Existing highways, village highways and rural tractor roads can be used for land transportation. Some temporary roads will also be built to connect the construction material grounds and other highways, roads and main construction area. Sand and rock processing systems will be located near the construction material grounds. Electric power supply will be obtained from nearby power networks. Water supply for production will come from the Yangtze, lakes and ponds; while drinking water will be drawn from treated tap water, or groundwater will be used following treatment. Total quantity of excavation is about 4.16 million m3, and that of filling is 44.17 million m3, thus a great quantity of fillings is needed for dyke body and dyke basis raising and strengthening. Needed rock materials will be purchased from special quarries. Earth materials mainly come from construction excavation sites on the dykes and from selected borrow grounds on the river beaches or on hills of the dyke- protected areas. Farmlands have been avoided as borrow grounds as much as possible. Construction spoils have been planned to be used as filling materials for rehabilitating the dykes and filling the borrow pits. For few borrow pits without enough filling materials to fill, they are to be reformed into fishing ponds at the request or agreement of farmers. In a word, there is no construction spoil needing special treatment for this project. Figure 2.4-1 shows a typical dyke cross-section and explains typical dyke stability problems. 2.4.2 Construction Methods for Main Items (a) Dyke raising This item will include base clearing, slope cutting, filling, concrete grouting, rock scattering, and planting turf and wave-break forest. Base clearing and slope cutting will be carried out by artificial methods. But auto- machines such as excavator and self-unload truck will be used to replace of manpower where the construction is intensive. Construction spoils will be transported by 2-6  YBFCP/EIA DRAFT FINAL CHAPTER 2: PROJECT DESCRIPTION manpower to dyke filling sites. Filling and construction will be carried out jointly by bulldozer, excavator, self- unloading automobile and compactors. Mixers will be used for concrete and reinforced concrete production; man-driven rubber-wheel carts used for transporting the concrete into the bar; shaking machines used for compacting. Aggregate will be produced in the rock exploitation grounds and sand produced in sand exploitation grounds. Rock laying construction includes masonry and dry-laid rock construction. The rock materials will be purchased from nearby exploitation grounds. The original need-to-be-removed masonry will be directly cleared with excavator and transported to filling sites with self-unloading trucks. Turf pavement and wave-break forest plantation will be planted artificially. Turf will be dug out nearby and plant seeds will be purchased. Self-unloading automobiles are to be used for transportation. (b) Treatment of the hidden defects in dyke body Grouting for the dyke body: Mainly hole grouting will be adopted. The holes will be arranged according to design, and the diameter of each hole will be plainly marked. After grouting, each hole will be filled with mud and compacted. Grouting for the dyke basis: Triple-tube spray method will generally be applied. Before construction, tests should be made in lab and on the spot. Ratio of all materials is to be tested in lab, and technical parameters of construction are to be determined in the on-the-spot tests. Fixed drillers will be used for drilling the holes. Seepage interception wall: Cement-soil seepage interception wall and flexible- concrete seepage interception wall will be used in the Project construction. The former will be mainly used for dykes of rural areas, for example, the Jingnan Dyke [Ref. 1 11]; while the latter for urban dykes such as the Jiujiang Dyke [Ref.107]. (c) Revetment Revetment aims at rehabilitating the banks where there exists serious erosion due to river flow scouring. Measures include scattering rocks, slope paring, rock-laying and aggregate paving for basis. For scattering rocks, underwater laying method will be adopted, i.e. rock will be transported by trucks from exploitation ground to the site, then orientation boats are used for locating, after that, open-body boats will be used for direct laying, or deck boat, or man-power is used for laying. Paring slopel: Slope paring will be done by men-power or by reverse excavators. The paved materials will be transported with self-unloading trucks to spoil grounds or to the inner platform for filling. ' Pare a cetain layer of earth away from the original dyke slope to meet requirement of the newly designed dyke slope. 2-7  YBFCPIEIA DRAFT FINAL CHAPTER 2: PROJECT DESCRIPTION Rock-casting Rock-casting construction includes loose stone and masonry laying. Rock mainly comes from the nearby exploitation ground. Before laying, the bases must be treated with gravel. Crossing-dyke structures: Construction for crossing-dyke structures will involve removing wasted old and risky gates, prolonging and rehabilitating existing culverts and gates, as well as building some new culverts and gates. Construction activities will include earthwork excavation, deep-layer mixing piles of the gate base, concrete removal, masonry removal, concrete placement, paving of loose stone and earth refilling. (d) Construction of dyke-top roads After the dyke body is raised to design elevation, sand and aggregate will be paved and compacted with rollers, then concrete is placed for the road surface, after that, the road shoulders are paved to the concrete surface level. See Figure 2.4-1. (e) Illustration Seepage interception walls in (b) and scattered rocks in (c) are to be built according to former layout, but they will be implemented with domestic fund not with WB fund. 2.4.3 Construction Schedule According to the project proposal reports of the three provinces, the overall construction period lasts for 3 years, in which, 3 years (1998.10-2001.6) for Hunan sub-project and 3 years (2000.8-2003.6) for Hubei sub-project. For Hubei, Jingnan dyke, Huanggang dyke and Wuhan dikes need 3 years to be completed and Bapu Dyke needs 2 years. Most of the project construction items can be carried out only from October to March except for a few items due to flood influence. Therefore, the construction of the Project reflects seasonal characteristics. Scheduling for each dyke should be made in consideration of its importance and degree of risk. Key dykes and dykes of highest risks will be given priority attention. 2.4.4 Summary of Construction Program Construction of the project is characterized with seasonal performance, extensive involvement, and high degree of mechanization. The construction will be laid out according to the following principles: keeping in coincidence with the local condition, being beneficial to construction, convenient to living of the constructor, easy management, safe and reliable, economical and reasonable [Ref.107]. Construction methods to be adopted are the commonly used ones in China for rehabilitation of dyke. The overall schedule is shown as Table 2.4-1. 2-8  YBFCP/EIA DRAFT FINAL CHAPTER 2: PROJECT DESCRIPTION 2.5 Comparison of Alternatives In the feasibility study stage, several alternatives have been studied. Their main points are discussed below: 2.5.1 Non-project Alternative Because the dykes have existed for a lonig time, although maintenance of the dykes has been carried out quite often, they still fail to reach the design standards [Ref. 103, 104, 106, 107, 111,130]. Main problems of these dykes are as follows: (a) Because the dykes were built many years ago, the soil texture is complicated, and the dyke body is often not of good quality. There exist conumon leaking phenomena. As the dykes are thin and low, sub-dykes often need to be built temporarily in a hurry when deluge comes, which usually consumes a large quantity of man-power and materials, and seriously affects the industrial and agricultural production in the areas. In addition, damage by termites, by making their homes in the dyke-body, is Very serious in many dyke sections and is often the main cause for bank-burst risk. (b) Geological condition of the dyke basis is rather poor, being usually of dual structure. The upper layer is usually thin and impermeable, while the lower layer is thick and highly permeable with the composition of silt sand and cobblestone. Besides, there are a lot of ponds that usually have close contact with the outside river. For these reasons, piping can often be seen during flood season. (c) River channels of some local sections, such as the Jingjiang section of the Jingnan dyke, are not stable. When deluge comes, flood flow usually erodes the bank and causes serious collapse. As a result, the beaches become narrower and narrower, and even disappear, which hides many dangers and seriously threaten the safety of the dykes. (d) There are many culverts of various sizes and gates in the dykes, most of which were built from 1950s to 1970s. Metal structures of many culverts and gates become eroded, the open and close facilities are aged. Besides, the bodies of gates are caved in to different degrees, and there exist many hidden defects such as decline, cracking, and culvert pipes not properly joined because of contraction and expansion. The above-mentioned problems show that if the dykes are kept in the present condition, they will not be able to defend against the 1954 or 1998-type floods. When the floods occur again, much higher cost will have to be paid. In the light of 1998 price levels, the annual loss incurred by flood is estimated to be higher than 100 billion yuan with this project not implemented. It is concluded, therefore, that rehabilitation of the dykes is urgently necessary in order to protect the local people's lives and properties, and improve the regional ecology and environment. The dykes are of primary importance in the overall flood control program as noted in Table 2.1-1. 2-9  YBFCP/EIA DRAFT FINAL CHAPTER 2: PROJECT DESCRIPTION 2.5.2 Other Alternatives Considered (a) Diversion and Storage Project The Yangtze flood is usually high in flood peak level, huge in volume, but the river channels in middle and lower reaches are limited in discharge capacity. Diverting and storing the extra floodwater is an effective measure to protect important areas. However, it is difficult for diversion and storage projects to solve the flood problem in the middle and lower basin alone. The planned diversion and storage projects, with a total storage capacity of 50 billion m3 [Ref