设计洪峰流量

7.3 Design Peak Flow Estimation设计洪峰流量预测

Analysis of reports published by the Sierra Leone Roads Authority (SLRA) identified the Regional Rational Method as most appropriate for predicting peak design flows in Sierra Leone (SLRA, 2006).The Road Drainage Manual (2006) produced by The South African National Roads Agency Limited recommends that the Rational Method be applied to catchment areas smaller than 15 km2. Due to the limited number of methods available for the determination of flood peaks in Sierra Leone, the Rational Method has also been used in catchment areas larger than 15 km2. Intensity Frequency Duration (FDI) data for determining design rainfall intensities were adapted from design storm profiles published in 'Climate Studies for Tonkolili, Sierra Leone: Stage 2 – Climate assessment and data analysis' (UK Met Office, 2010) in combination with daily rainfall records for Freetown. The IFD data adopted for design are presented in Appendix A.

塞拉利昂公路局(SLRA)公布的分析报告中指出，“区域性推理法”是预测塞拉利昂地区洪峰设计流量的最恰当的方法 (SLRA,2006)。南非国道代理有限公司编制的公路排水手册(2006)建议该推理法可应用于小于15平方公里的集水区。但出于可用于确定塞拉利昂洪峰流量的方法有限，该推理法也同样被应用于大于15平方公里的集水区。强度频率时间（IFD）数据是根据“塞拉利昂，唐克里里的气候研究：阶段2—气候评估和数据分析” (英国气象局，2010)上发布的暴雨设计剖面图，并结合弗里敦日常的降雨记录获得的，用以确定设计降雨强度。设计中采用的IFD数据在附录A中。

Runoff coefficients were estimated using regressions performed on curves found in the Urban Stormwater Management Manual for Malaysia (2000). These curves relate runoff coefficients to rainfall intensities and soil type, and were considered to be applicable to the Sierra Leone region, in the absence of sufficient information on land/soil conditions. This information can be used to estimate design flows using the Rational Method up to the 50 year ARI event. Flood frequency analysis was performed on extreme flows estimated for various sites in Sierra Leone, published in Lahmeyer International’s Sewa Dam Project report. The results of this flood frequency analysis were used to develop frequency factors, which were applied to Rational Method design flows, to calculate design flows in excess of the 50 year ARI. The frequency factors adopted for design are presented in Table 7-2 Frequency Factors below.

径流系数是通过对马拉西亚城市雨水管理手册（2000）中的曲线进行线性回归来预测的。这些曲线表示的是径流系数与降雨强度和土壤类型之间的关系，在当前关于土地/土壤情况的信息不足的条件下，这些曲线被认为可以应用于塞拉利昂地区。在用推理法预测最高50年平均复发间隔（ARI）事件的设计流量时，可以用到这些信息。洪水频率分析是针对雷米尔顾问公司Sewa水坝项目报告中发布的塞拉利昂各个地区的预测极限流量进行的。洪水频率分析结果用来开发频率因素，应用于推理法设计流量中，以计算超过50 年ARI的设计流量。设计采用的频率因素在下面的表格7-2频率因素中。

Table 7-2 Frequency Factors表格7-2 频率因素 ARI (yrs) 2 5 10 50 100 200 500 1000 10,000,000 CY/C2 1 5 8.0 10.1 10.8 11.6 12.8 13.8 26.2

It is good practice in the determination of design floods for bridges or large culverts to use more than one method for estimating peak flows and if historical streamflow data is available, it should be analysed as well. In the absence of additional published methods for determining peak flows in Sierra Leone, flood frequency analysis of streamflow data presented in the Hydrological Yearbook of Sierra Leone (UNDP, 1976) and in the Power Sector Master Plan for Sierra Leone will be used to confirm design flows. However the use of flood frequency analysis may be limited by the extent and duration of available streamflow records.

在确定桥梁或大型涵洞的设计洪水时，使用多种方法来预测洪峰流量是很好的做法。如果历史流量数据可以获得，也可以对其进行分析。在没有其他可行方法来确定塞拉利昂洪峰流量的条件下，对塞拉利昂水文年鉴（UNDP, 1976）和塞拉利昂电力领域中的水流数据所进行的洪水频率分析将被用来确认设计流量。然而，可以获得的水流记录的范围和持续时间可能会洪水频率分析的使用。

汉译英翻译

设计图纸Design drawing

1. 用地范围的区域位置；

Site scope regional setting;

2. 用地红线范围（各角点测量座标值、场地现状标高、地形地貌及其它现状情况反映）；

Property line scope (Coordinate value measured on each angular point, existing site evaluation, topography conditions and reflections on other existing situations)

3. 用地与周围环境情况反映（如用地外围城市道路；市政工程管线设施；原有建筑物、构筑物；四邻拟建建筑及原有古树名木、历史文化遗址保护等）。

Reflections on the situations of the land and surrounding areas (Such as urban roads surrounding the site; Municipal engineering pipeline facilities; Original buildings and structures; Proposed buildings around as well as existing ancient and original trees, historical and cultural sites protection, etc. )

4. 总平面布局，其功能分区、总体布置及空间组合的考虑；道路广场布置；场地主要出入口车流、人流的交通组织分析（并应说明按规定计算的停车泊位数和实际布置的停车泊位数量）；以及其它反映方案特性的有关分析；消防、人防、绿化等全面考虑。

General floor plan, including considerations on function

organization, overall layout and space combination; Roads and squares layout; Traffic organization analysis on the vehicle flows and human flows at the main exits and entrances (in which the number of parking units calculated according to regulations and the number of them actually arranged should be pointed out); Other relevant analysis that can reflect the scheme feathers; Considerations on Fire control, civil air defense, Greenland building and other aspects)

5．根据项目特点和招标人的要求提供的功能分析图、交通分析图、环境绿化景观分析图、日照分析图、内部流线分析图等

Function analysis diagram, traffic analysis diagram, environment landscaping analysis diagram, sunlight exposure analysis diagram and interior streamline analysis diagram, etc., provided according to the project characteristics and requirements of the tenderee.