How to write the preface of reservoir danger removal and reinforcement

This is from our own unit for reference! Mainly introduces the background of the project

Basin Overview A certain reservoir is located 2 km south of the urban area of ??** City, *** Province, about 25 km east of ** City, and is located in the ** river system* of the ** river basin In the middle reaches of the ** river tributary, the XX reservoir controls a basin area of ??44.5 km2 below the ** reservoir, with a total storage capacity of 18.85 million m3 and a Xingli storage capacity of 9.1 million m3. It is a medium-sized reservoir. There are four small reservoirs **, **, **, and ** in the upper reaches and one medium-sized reservoir ** in the upper reaches, and there is a ** reservoir (medium-sized) in the lower reaches.

Project Overview: The flood control standard of a certain reservoir is designed for a 100-year return, and is verified for a 2000 return. The design maximum flood level is 155.44 m. The hub project consists of a dam, spillway, water discharge pipe, etc. The dam is a homogeneous earth dam with a dam crest elevation of 156.2 m (Yellow Sea elevation, the same below) and a maximum dam height of 26.4 m. The open spillway on the river bank is located on the left bank of the dam, with an entrance elevation of 149.50 m and a maximum discharge volume of 2000 m3/s. The discharge pipe is set on the right bank of the dam. The discharge pipe gate is a vertical opening and closing flat steel gate with an inlet elevation of 138.00 m and a maximum discharge of 2.0 m2/s.

Project History The construction of a certain reservoir started in 1959 and was completed in 1961. Later, through continued construction and risk removal and reinforcement, the quality and appearance of the reservoir project were improved, and good benefits were achieved. After years of management and application, the reservoir has developed into a reservoir that focuses on flood control, taking into account irrigation, water supply, fish farming, and tourism with significant comprehensive benefits. In particular, the reservoir is located at the urban-rural fringe, with convenient transportation and beautiful environment, and has great potential for developing tourism. The advantage of being unique. At the same time, the National Highway passes through the top of the dam, and the appearance of the reservoir project is directly related to the image of the city's water conservancy industry. Therefore, higher requirements are put forward for the construction and development of the reservoir itself. However, due to the constraints of economic and technical conditions at the time of building the reservoir, the quality of the project construction was not high and the facilities were not complete enough. Although they have been repaired and reinforced, there are still many remaining problems. The most prominent ones are that the spillway has no energy dissipation facilities and the tailrace channel has not been built as necessary. protection, and has limited overcurrent capability, etc.

According to the "Reply on the Hydrology Review of ***** Reservoir" (No. ***), the design flood standard for the spillway of a certain reservoir is once in 100 years, and the design peak flow is 1120 m3/s(* *~** interval), the corresponding maximum discharge flow of the spillway is 980 m3/s; the calibrated flood standard is once in 2000, the calibrated peak flow is 1960 m3/s (Dingdian~Chulou interval), the corresponding maximum discharge flow of the spillway is 1960 m3/s.

Necessity of construction In June 2006, the upstream ** reservoir was in danger and the storage capacity was emptied urgently. The spillway of the XX reservoir passed water for the first time. It lasted for 8 days and the maximum discharge flow was about 4.0 m2/s. Since no energy-dissipation engineering was built behind the steep slope of the spillway, the discharged water caused a deep gully to form from the steep slope of the spillway to the main channel of the river, directly threatening the life and property safety of the spillway project, the dam, the downstream ** Railway and the people of ** City. After the danger occurred, *** reported the danger to the police in a timely manner and organized a consultation with experts. They unanimously agreed that it was necessary to eliminate the danger and reinforce the spillway as soon as possible.

Entrusted by the Reservoir Management Office of ** City, ** Design Institute designed the spillway risk relief and reinforcement project. The main contents include: the stilling pool, sea flood and tailrace channel behind the steep slope of the spillway. .

Design basis On September 12, 2006, *** organized a review meeting on the "Design of Reservoir Spillway Relief and Reinforcement Engineering in ** City" in **. The ** Provincial Department of Water Resources and ** Leaders and experts from the Municipal Water Conservancy Bureau, ** Municipal Water Conservancy Bureau, XX Reservoir Management Office and other units were invited to attend the meeting. The participants listened to the **Design Institute's report on the "Design Report for the Hazard Removal and Reinforcement Engineering of a Reservoir Spillway in ** City" submitted for review, conducted careful discussions, and formed review opinions (Annex 1).

Determination of construction content. This design will be modified and improved based on review opinions. Due to limitations in various aspects such as funds, this design makes an overall plan for the energy dissipation and anti-scour project of a certain reservoir spillway and the tailrace channel project, and implements them in phases.

The main contents of the first phase of the spillway risk relief and reinforcement project of a certain reservoir include: the stilling pool behind the steep slope of the spillway and part of the overflow section. This construction drawing design is mainly for the first phase of the project. The planning, design and implementation arrangements for the second phase of the project shall be determined separately by Party A based on the future operation of the reservoir.