ĐÁNH GIÁ SỰ THAY ĐỔI SỨC TẢI LŨ TRÊN SÔNG SÀI GÒN=ĐÁNH GIÁ SỰ THAY ĐỔI SỨC TẢI LŨ TRÊN SÔNG SÀI GÒN

0 Người đánh giá. Xếp hạng trung bình 0

Tác giả: Nguyễn Bình Dương, Đinh Công Sản

Ngôn ngữ: vie

Ký hiệu phân loại:

Thông tin xuất bản: Tạp chí Khoa học và Công nghệ Thủy lợi, 2018

Mô tả vật lý: tr.36

Bộ sưu tập: Báo, Tạp chí

ID: 488574

Thêm vào giỏ

Bài báo tổng hợp kết quả đánh giá khả năng tải lũ của sông Sài Gòn của đề tài KHCN cấp nhà nước KC08.07/16-20 “Nghiên cứu đề xuất giải pháp nâng cao hiệu quả sử dụng nước, đảm bảo an toàn công trình đầu mối và hạ du hồ Dầu Tiếng trong điều kiện biến đổi khí hậu, thời tiết cực đoan” sử dụng một số kết quả nghiên cứu trước đây, tài liệu khảo sát địa hình và kết quả tính từ mô hình toán (MIKE11). So sánh mực nước và lưu lượng xả lũ tương ứng dọc theo sông Sài Gòn cho thấy khả năng tải dòng chảy của sông Sài Gòn gia tăng vùng thượng lưu và giảm đi ở vùng hạ du. Cụ thể là tại mặt cắt ngang trạm Dầu Tiếng, với mực nước lũ đạt 6,0 m, lưu lượng tải năm 1984 chỉ đạt 650 m3/s, năm 2005 đạt 1.300 m3/s và đến năm 2017 đạt tới 2.200 m3/s, tức là tăng tới 47 m3/năm, tương đương với khoảng 7.2% năm. Dọc theo sông Sài Gòn khả năng tải dọc sông Sài Gòn gia tăng từ Km 0 (chân đập) về đến Km 100. Ngược lại, khả năng tải dọc sông Sài Gòn giảm đi từ khoảng Km100 về hạ du. Nguyên nhân của việc gia tăng sức tải trên sông Sài Gòn ở đoạn thượng lưu chủ yếu là do thay đổi về địa hình. Lòng dẫn sông sẽ có xu thế bị xói sâu hơn do tác động của xói sau công trình, hoặc có thể là do khai thác cát làm cho mặt cắt bị hạ thấp ở đoạn sông thượng lưu đến Km100. Ngược lại, ở đoạn sông từ Km100 về hạ du, đáy sông có xu thế bồi lên và thêm vào đó, có thể là do sông bị lấn chiếm (đô thị hóa), hoặc do đắp đê bao dẫn đến thu hẹp mặt cắt ướt, làm sức tải giảm đi.The aim of this article is to summarize the result of evaluation the flow transport capacity of the Sai Gon River using historical data, topographical survey and results from numerical models (MIKE11) in the state-level scientific research project KC08.07/16-20 "Research and propose solutions to improve water use efficiency, ensure the safety of main works and downstream Dau Tieng reservoir in the conditions of climate change and extreme weather ". The comparisons of water levels and flow discharges correspondingly along the Saigon River showed that the flow transport capacity of the Saigon River increased in the upstream part and decreased in the downstream part. Specifically, at the cross-section of Dau Tieng station, with the flood water level of 6.0 m, the discharges in 1984 was only 650 m3/s, in 2005 reached 1,300 m3/s and reached 2,200 m3/s by 2017, ie increased up to 47 m3/year, equivalent to about 7.2% per year. Along the Saigon River the flow transport capacity increased from Km 0 (the dam site) to Km 100. Conversely, the flow transport capacity of the Saigon River is reduced from about Km100 to downstream. The increase in flow transport capacity on the Saigon River at the upstream part is mainly due to changes in topography. River beds tend to be deeper due to the impact of post-dam construction erosion, or it may be due to sand mining that made river bed lowering from upstream sections to Km100. In contrast, from Km100 downstream, the river bed tends to accret, and in addition, possibly due to due to encroachment (urbanization), or by dike embankments leading to the narrow cross sections, making flow transport capacity reduced.

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