SL 269-2001 in English

1 General Provisions

1.0.1 This code is developed with a view to unifying technical criteria on design of desilting basin in diversion structure of water conservancy and hydropower project, ensuring design quality and promoting the engineering development of the desilting basin.

1.0.2 This code is applicable to the design of Grade 3 desilting basin or above for treatment of suspended sediment in large and medium-sized water conservancy and hydropower projects.

1.0.3 In the design of the desilting basin, the basic data analysis shall be properly carried out. For important projects, combined method of theoretical analysis and model test is applied to determine the main arrangement dimension of the desilting basin.

1.0.4 For the arrangement and design of the desilting basin, technical and economical comparison must be carried out.

1.0.5 For the desilting basin, operation design shall be carried out and shall be consistent with the operation of the hydroproject.

1.0.6 In the design of the desilting basin, sediment prototype observation and safety monitoring designs shall be proposed.

1.0.7 The design of the desilting basin shall not only comply with this code, but also shall meet those specified in the relevant current national and professional standards.

2 Terms and Main Symbols

2.1 Terms

2.1.1 desilting basin

the structure used to settle the suspended sediment whose sediment particle in sediment-laden flow is greater than the design settling diameter and reduce the sediment concentration in water flow

it may be classified into hydraulic flushing desilting basin and non-flushing desilting basin according to operation modes. The former may be sub-classified into continuous flushing desilting basin and periodic flushing desilting basin

2.1.2 continuous flushing desilting basin

the desilting basin that continuously flushes the settled sediment into the downstream watercourse during continuous water supply. The continuous flushing desilting basin consists of upstream connection section, working section, downstream connection section and flush gallery, as shown in Figures 2.1.2-1 and 2.1.2-2

Foreword i
1 General Provisions
2 Terms and Main Symbols
3 Design Data
4 Arrangement Conditions of Desilting Basin and Design Criteria of Sediment Settlement
5 Selection of Position and Type
6 Project Arrangement
7 Determination of Main Dimension
8 Structural Design
9 Operation Design
10 Prototype Observation and Safety Monitoring Design
Annex A Settlement Calculation Method
Annex B Settling Velocity Calculation of Suspended Sediment
Annex C Flushing Calculation of Periodic Flushing Desilting Basin for Water Conservancy Project
Annex D Hydraulic Calculation for Pressure and Non-pressure Sediment Flushing of Desilting Basin at Hydropower Station
Explanation of Wording in this Code