NB/T 10085-2018Code for hydrological forecasting of hydropower projects (English PDF)

Foreword

This document was issued on 29 October 2018 by the National Energy Administration of the PRC and takes effect on 1 March 2019.

It is a NB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

It is classified under ICS 27.140, Chinese classification P59.

This code was formulated in accordance with the requirements of the Notice of the National Energy Administration on Issuing the Second Batch of Energy Industry Standard Formulation (Revision) Plans for 2014 (Guo Neng Ke Ji [2015] No. 12). The drafting group carried out extensive investigation and research, carefully summarized practical experience and, on the basis of widely soliciting opinions, formulated this code.

The main technical contents of this code are: basic data, flood forecasting, runoff forecasting, ice forecasting and tide forecasting, hydrological forecasting during river closure and reservoir impoundment, rating criteria of forecasting schemes, and operational forecasting.

The National Energy Administration is in charge of the administration of this code. China Renewable Energy Engineering Institute proposed it and is responsible for its routine management, and the Energy Industry Standardization Technical Committee for Hydropower Planning and Reservoir Environmental Protection is responsible for the explanation of specific technical contents. Comments and suggestions arising during implementation should be sent to China Renewable Energy Engineering Institute (address: No. 2 Liupukang North Street, Xicheng District, Beijing; postcode: 100120).

Chief development organizations: China Renewable Energy Engineering Institute; PowerChina Zhongnan Engineering Corporation Limited.

Participating development organizations: PowerChina Chengdu Engineering Corporation Limited; Yalong River Hydropower Development Company, Ltd.; China Yangtze Power Co., Ltd.

Chief drafting staff: Yan Zhonglin, Yang Baiyin, Zhang Yang, Gao Jie, Fei Rujun, Liu Jingyi, Wang Tao, Huang Peijin, Yu Hao, Cao Yuanyuan, Li Ming, He Zhaohui, Liu Zhiwu, Liang Jun.

Chief reviewing staff: Wan Wengong, Zhang Min, Zhou Xinchun, Liu Guangbao, Cao Changxiang, Ye Xugang, Xia Jianrong, Zhao Jimin, Yang Zhongmin, Li Xiaowei, Yu Fuliang, Shi Peng, Wang Yuhua, Dong Xianyong, Cai Pin, Piao Ling, Li Shisheng.

Publication data

Energy Industry Standard of the People's Republic of China NB/T 10085-2018, Code for Hydrological Forecasting of Hydropower Projects. ICS 27.140; CCS P 59; filing number J2609-2018. Issued on 2018-10-29 and implemented on 2019-03-01 by the National Energy Administration.

Chief development department: China Renewable Energy Engineering Institute. Approval department: National Energy Administration. Implementation date: March 1, 2019. Published by China Water and Power Press, Beijing, 2019.

Announcement of the National Energy Administration

National Energy Administration Announcement No. 12 of 2018: in accordance with the relevant provisions of the Notice of the National Energy Administration on Issuing the Administrative Measures for Standardization of Energy Industry Standards (Trial) and Their Implementation Rules (Guo Neng Ke Ji [2009] No. 52), and upon review, the National Energy Administration approved 204 industry standards, beginning with Air-cooled Speed-regulating Magnetic Coupling for Mining, comprising 54 energy standards (NB), 8 petrochemical standards (NB/SH) and 142 petroleum standards (SY), which are hereby issued. National Energy Administration, October 29, 2018.

In the attached catalogue of industry standards, NB/T 10085-2018 Code for Hydrological Forecasting of Hydropower Projects is listed as item No. 40, with no standard superseded and no adopted international standard; approval date 2018-10-29, implementation date 2019-03-01.

Remaining chapters (from the official table of contents)

Chapter 5 Runoff Forecasting (pages 8 to 9): 5.1 General Requirements; 5.2 Contents and Methods of Runoff Forecasting Schemes; 5.3 Rating and Verification of Runoff Forecasting Schemes; 5.4 Applicability of Runoff Forecasting Schemes.

Chapter 6 Ice Forecasting and Tide Forecasting (page 10): 6.1 General Requirements; 6.2 Ice Forecasting; 6.3 Tide Forecasting.

Chapter 7 Hydrological Forecasting during River Closure and Reservoir Impoundment (page 11): 7.1 Hydrological Forecasting during River Closure; 7.2 Hydrological Forecasting during Reservoir Impoundment.

Chapter 8 Rating Criteria of Forecasting Schemes (pages 12 to 15): 8.1 Forecast Error, Permissible Forecast Error and Forecast Qualified Rate; 8.2 Rating Criteria of Flood Forecasting Schemes; 8.3 Rating Criteria of Runoff Forecasting Schemes; 8.4 Rating Criteria of Ice Forecasting Schemes; 8.5 Rating Criteria of Tide Forecasting Schemes.

Chapter 9 Operational Forecasting (pages 16 to 19): 9.1 Hydrological Stations Network and Water Regime Information; 9.2 Requirements for Organization and Personnel; 9.3 Software Systems and Forecasting Operations; 9.4 Information Reporting and Dissemination; 9.5 Forecast Accuracy Evaluation; 9.6 Forecast Analysis and Summary.

Appendix A Contents of Flood Forecasting Scheme Report (page 20), referred to in clause 4.2.8.

Appendix B Contents of Runoff Forecasting Scheme Report (page 21).

Explanation of Wording in This Code (page 22); List of Quoted Standards (page 23).

Addition: Explanation of Provisions (from page 25), giving the explanatory notes to the clauses of the code.

1 Scope

NB/T 10085-2018 is the Chinese code for hydrological forecasting on hydropower projects, both during construction and in operation. Forecasts are what allow a reservoir to be run safely and profitably: a flood forecast tells the operator how much to draw down before the peak arrives, an inflow forecast sets the generation schedule, and on a construction site a forecast is what decides whether the cofferdam will be overtopped during river closure. The code sets the general provisions, the defined terms and symbols, and the basic requirements on the data, the hydrometric station network and the forecasting system. It then covers the forecasting of each phenomenon: flood forecasting by rainfall-runoff models and by routing, medium and long range runoff forecasting for dispatch planning, ice forecasting where freeze-up and break-up affect intakes and structures, and tidal forecasting for plants near estuaries. Forecasting for construction is treated separately - during river diversion and closure, and during the first filling of the reservoir. The code sets the criteria by which a forecasting scheme is evaluated and graded before it is used, the permitted error of each type of forecast, and the operational forecasting procedure: data collection, real-time correction, issue of forecasts and warnings, and the post-event evaluation of accuracy. The management of the forecasting system and its records close the document.

1.0.1 This code is formulated to standardize the work contents, methods and technical requirements of hydrological forecasting for hydropower projects.

1.0.2 This code is applicable to hydrological forecasting of hydropower projects.

1.0.3 Hydrological forecasting during the construction period of a hydropower project shall be compatible with the requirements of construction flood control, flood passage and reservoir impoundment; hydrological forecasting during the operation period shall be compatible with the requirements of project flood control safety, reservoir operation and the electricity market.

1.0.4 Hydrological forecasting for hydropower projects shall mainly include flood forecasting, runoff forecasting, ice forecasting and tide forecasting.

1.0.5 In addition to this code, hydrological forecasting for hydropower projects shall also comply with the current relevant standards of the nation.

2 Terms

2.0.1 hydrological model: a physical structure, or a mathematical and logical structure, established to simulate hydrological phenomena.

2.0.2 forecasting element: a physical quantity of the hydrological regime at a certain location or in a certain area at a certain time that is to be forecast, including discharge, water level, flow velocity, ice thickness, etc.

2.0.3 forecast lead time: the time interval between the last time of the hydrological data on which a forecast is based and the time of occurrence of the forecasting element.

2.0.4 permissible forecast error: the permissible range of forecast error determined comprehensively from aspects such as the requirements for use of the forecast results and the technical level of forecasting.

2.0.5 deterministic coefficient: an index indicating the degree of agreement between the forecast flood hydrograph and the observed hydrograph.

2.0.6 forecast-based time: the last time of the hydrological data on which a hydrological forecast is based.

2.0.7 qualified forecast: a forecast in which the forecast error of the forecasting element is within the permissible error.

2.0.8 forecast qualified rate: the percentage of the number of qualified forecasts of a forecasting element in the total number of forecasts.

3 Basic Data

3.0.1 The basic data for developing forecasting schemes shall mainly include the following: 1) hydrological and meteorological data, including water level, discharge, precipitation, evaporation, ice regime, tide level, etc.; 2) data on the underlying surface of the basin, including basin topography, vegetation conditions, groundwater level, thickness of the unsaturated (aeration) zone, etc.; 3) data on related projects, including the construction progress of the project and the construction status of upstream and downstream cascades, etc.

3.0.2 The hydrological and meteorological data used for developing forecasting schemes shall meet the requirements of reliability, representativeness and consistency.

3.0.3 The basis stations used for developing forecasting schemes shall be consistent with the basis stations of operational forecasting, and a database shall be established in accordance with the requirements of the hydrological database table structure and identifiers for hydropower projects.

3.0.4 The data series used for developing flood forecasting schemes shall be not less than 10 years and shall include representative years of large, medium and small floods; the number of representative flood events shall be not less than 50 in humid regions and not less than 25 in arid regions, and all floods larger than the median flood peak of the sample shall be used. When data are insufficient, all available flood data shall be used.

3.0.5 The data series used for developing short-term runoff forecasting schemes shall be not less than 10 years; the data series used for developing medium- and long-term runoff forecasting schemes shall be not less than 30 years. When data are insufficient, all available runoff data shall be used.

3.0.6 The number of representative samples used for developing ice forecasting schemes shall be not less than 30. When samples are insufficient, all available ice regime data shall be used.

3.0.7 When developing tide level forecasting schemes, storm surge forecasting schemes shall use tide level data of not less than 10 tropical (extratropical) cyclones, and normal tide level forecasting schemes shall use hourly continuous tide level data of not less than 1 year, including high tide levels, low tide levels and the corresponding tide times. When data are insufficient, all available tide level data shall be used.