黄河北干流河道泥沙的输移与沉积

Sediment Transportation and Deposit in North Main Reaches of Yellow River

河口镇－龙门区间有２３１６６ｋｍ２面积属于未控区，占河口镇－龙门区间面积的２０％。根据降雨量与输沙模数相关图，推求出来控区产沙量，并按沙量平衡原理得出北干流河道泥沙冲淤基本规律，即洪水期河道淤积，河口镇以上来洪水时，则上段冲刷下段做冲或微淤；府谷至吴堡区间发生洪水时，发生淤积，其下段河道微淤；吴堡以下区间发生洪水时，有淤有冲。ｄ＜０．０１ｍｍ泥沙含量大于１００ｋｇ／ｍ３的洪水有利于冲刷，甚至使壶口以下河道出现揭底冲刷；非洪水期或非汛期河道发生冲刷，上段冲刷量大，下段微冲甚至微淤，当ｄ＞０．０５ｍｍ沙重占５０％以上时，淤积量可达０．５亿ｔ以上。淤积过程全沙淤积量小于ｄ＞０．０５ｍｍ泥沙淤积量，冲刷过程全沙冲刷量大于ｄ＞０．０５ｍｍ泥沙冲刷量。１９６４～１９８８年２５年全沙年均淤积量为０．０９９亿ｔ。

here are uncontrolling area of 22, 313km2 in the region between Hekozhen to Longmen,which.is account for 20%. of the total area. The paper inquired into the sediment yield in the uncbntrolling area on the basis of precipitation and sediment transportation relation curver,and obtained basic erosion and accumulation law of river tunnel of north main reaches according to sediment yield banlance principle, i. e.,accumulation takes place in flood poriods; the upper reaches are eroded and the lowers eroded or deposited sightly when floods come from upper Hekozhen,accumulation occurs when there are flood between Fugu and Wubu,and lower reaches are silted a little;and when. floods happen in lower Wubu,some reaches are silted and some eroded. Floods with d<0.01mm and sediment content over 100kg/m3 are favourable to erosion, even bottom tearing scour in lower Huko reaches. River channel erosion occurs in nonflood seasons or dry seasons,the upper reaches are eroded with much volume,the lowers eroded a little and sometimes deposited. When floods are with d> 0. 05mm and sediment weight of over 50%, accumulation amount may be over 50 million tons. The total sediment accumulation is smaller than that of d>0. 05mm during deposition,and the total sediment erosion is over than that of d>0. 05mm during erosion process. The average accumulation of 25 years from 1964 to 1988 is 9. 9 million tons.