一、采金船碍洪情况 勉县黄金公司100升采金船,建造于1985年,连续四年都在汉江堤外渡汛、汛后入江作业生产。1989年以来,勉县黄金公司多方寻找借口,擅自决定采金船在江内渡汛。进入汛期后,采金船边采掘边向围堤位置靠近,其作业丢弃的砂石,在河道形成顶宽15米,底宽45米,高5～8米,长100米,体积约2万立方米的堆体,占去河道一半以上断面,形成汉江平川段最大的人为行洪障碍。它使河道水位抬高,主流改向,流速加大,堤基冲刷,严重危及堤防及保护区内人民生命财产安全。 1990年7月6日汉江特大洪水时,该采金船挡水围堤壅水0.5米左右,使上游300米处的“小汉江”回水,20米堤防垮滑约100立方米,造成危局,由于该段堤防堤顶超高近1米,才幸免漫顶决堤;1992年7月14日和8月20日两次较大洪水,由于 First, gold shipbuilding flood situation Mianxian Gold 100 liters gold mining vessels, built in 1985, for four consecutive years in the Han River embankment flood, after the flood into the river operations. Since 1989, Mianxian Gold Company has been looking for an excuse for many reasons and has arbitrarily decided to take gold mining vessels in the river for flood control. After entering the flood season, gold mining vessel side edge to the embankment excavation location, its disposal of sand and gravel in the river to form the top width of 15 meters, the bottom width of 45 meters, 5 to 8 meters high, 100 meters long, the volume of about 20,000 The cubic meters of piles occupy more than half of the river sections and form the largest man-made flood hurdle in the Han River Hirakawa section. It makes the river level elevation, the mainstream of redirection, flow rate increases, embankment erosion, seriously endangering the embankment and the people’s lives and property within the protected area. July 6, 1990 Hanjiang extraordinarily large flood, the mining gold retaining dam embankment water about 0.5 meters, 300 meters upstream of the “small Hanjiang” backwater, 20 meters embankment collapse about 100 cubic meters, resulting in a crisis , Due to the embankment dike near the ultra-high 1 meter, was spared the overpressure burst; July 14 and August 20, 1992 two major floods due to