On July 4, 2002 (May 24, 2002 in the lunar calendar), the Yellow River diverted water and sediment for the first time. On July 4, the Yellow River conducted its first water and sediment regulation test. At 9:00 a.m. on July 4, 2002, with an order, multiple gates of the Xiaolangdi Reservoir of the Yellow River were slowly raised in turn, and huge water gushed from the diversion tunnels at different levels rushed to the riverbed of the lower Yellow River. The Yellow River's first large-scale water and sediment regulation test has officially begun. This is by far the largest artificial prototype test in the history of world water conservancy. This test is to control water and sediment through the Xiaolangdi Reservoir, change the imbalance of water and sediment into a balance of water and sediment, and form a water potential that is conducive to river bed scouring. It provides scientific data for the long-term operation of the Xiaolangdi Reservoir and the reduction of sedimentation in the downstream river, thereby achieving the goal of "not raising the river bed". The Yellow River flows through the Loess Plateau, and as much as 1.6 billion tons of sediment enters the lower reaches of the Yellow River every year, of which 400 million tons are deposited on the river bed, causing the lower reaches to be silted and raised at an average rate of 10 centimeters per year. A suspended river is formed in the lower reaches of the Yellow River. Reducing sediment deposition has always been the goal that experts in Yellow River control have been pursuing throughout the ages. Years of research have shown that floods in the lower reaches of the Yellow River greater than 2500 cubic meters per second, coupled with other related factors, can scour the downstream river bed, thereby reducing sedimentation in the Yellow River and even achieving a balance between erosion and deposition, thereby fundamentally stopping the river bed. Rise. Water and sediment regulation of the Yellow River is an extremely complex systematic project. It is necessary to fully predict water conditions such as reservoir water storage, river water, and future weather forecast. It is also necessary to consider scouring, silting, and engineering accidents of nearly a thousand kilometers of river beds from the Xiaolangdi Dam to the estuary. Work conditions such as water diversion, evaporation, flooding, scouring and silting on both sides of the river during the water and sediment regulation process, a lot of scientific analysis and calculations and active cooperation from all parties are required. To this end, after years of research by scientific researchers, the flow and sediment concentration control indicators for this water and sediment control test have been determined to be 2600 cubic meters per second for Huayuankou section and 2300 cubic meters per second for Aishan section. The sediment concentration does not exceed 20 kilograms per cubic meter. According to reports, according to this indicator, after 10 days of testing, about 24.4 million tons of sediment can be washed out in the Lijin section from the downstream Tiexie to the estuary. In order to conduct the Yellow River water and sediment regulation test, the Yellow River Water Conservancy Commission of the Ministry of Water Resources has made comprehensive arrangements and arrangements. Through scientific dispatch, the Xiaolangdi Reservoir has stored water to 4.3 billion cubic meters without affecting water use on both sides of the river, providing a reliable guarantee for the test. The scope of this test includes more than 900 kilometers of river sections from Xiaolangdi Reservoir to the estuary in Shandong, and 161 fixed sedimentation test sections have been set up on more than 900 kilometers of river courses. For this reason, Shandong and Henan provinces have closed all Yellow River Diversion Gates to avoid water loss; thousands of embankment workers have been organized to make preparations such as materials and emergency rescue to cope with sudden dangers. Shandong has also demolished more than 40 floating bridges on the river to ensure smooth water flow and accurate measurement data.