Why didn't the sand from the Yellow River be used directly when the sand was so expensive in Gai Lou?

Most of the Yellow River sand is not suitable for building sand.

The sand in the Yellow River is useful, but there are few sand and gravel resources that can be used in the Yellow River. Although most of the coarse sand of the Yellow River can't be washed away and is deposited in the river course, which leads to the Yellow River becoming a suspended river on the ground, it should be noted that the so-called coarse sand of the Yellow River is particles larger than 0.05 mm, which is far from the 4.75 mm particles of building sand and is too fine. So a lot of Yellow River sand is not suitable for building sand. The following picture shows all kinds of building sand and gravel that meet the requirements.

Sand mining in the Yellow River is for public welfare and profit.

Due to a large amount of sediment deposition in the lower reaches of the Yellow River, the river channel shrinks and becomes a suspended river on the ground, which reduces the water transport capacity and is prone to minor floods and major disasters. Therefore, the strategy of harnessing the Yellow River is to widen the river course and strengthen the dikes. The so-called "dike consolidation" means constantly heightening and strengthening dikes and improving flood control capacity. The Yellow River Conservancy Commission has raised and thickened the Yellow River levee three times, and most of the reinforcement materials are directly excavated from the Yellow River, with a total sand collection of about 400 million cubic meters.

In addition to strengthening the river bank, the commonweal sand mining has actions in beach management, river regulation and river dredging, and the average annual commonweal sand mining amount is about 654.38+ 1 100 million tons.

In addition to public sand mining, the Yellow River Committee also plans for-profit sand mining, which is what everyone cares about. The scope of sand mining includes the main stream of the Yellow River, 12 tributaries of the Yellow River and the old lake area of Dongping Lake. The total amount of sand mining control in the whole year was 68.24 million tons, including 27 1 1 10,000 tons above Yumenkou, the main stream of the Yellow River, accounting for 39.7% of the total amount of control in the whole basin. Branches account for 56.5% of the total; The area of Dongping Lake accounts for 3.8% of the total area.

However, in the process of mining the Yellow River sand, there are still phenomena of over-exploitation, indiscriminate mining and illegal mining, which have affected the flood control safety. For example, in 20 12 years, the amount of sand mining above Tongguan in the middle reaches of the Yellow River will reach1.93 ~ 295 million tons.

Therefore, the sand of the Yellow River is not forbidden to be mined, but how to mine it in an orderly and planned way, taking into account the safety of the river.