植被恢复与重建过程中小流域降雨及水沙变化特征研究

Study on the changing characters of precipitation,water and sediment in vegetation recovery and rebuilding of small watershed

以女儿寨小流域为研究对象,着重研究了植被恢复与重建过程中小流域系统的降雨和水沙变化特征,并对植被恢复过程中的总体减沙水平做了分析.结果表明:①受大气环流的影响,小流域年际降雨量差异较大;小流域降雨年内时间分布极为不均,集中性很大,主要集中在汛期(4～8月),但年内降雨量的月间分布趋势基本一致.②小流域迳流年际变化很大,迳流年内分配不均,迳流集中是该小流域迳流变化的一个显著特征;小流域的植被恢复与重建对洪峰的出现和洪峰流量具有明显的延缓和削减作用.③径流(Qi)主要来源于降水(Pi),二者呈明显的一元线型关系:Pi=115.7678+2.7386Qi.④小流域的年输沙模数与年迳流量的变化规律基本一致,小流域年内产沙也高度集中,且与降水、迳流关系密切,小流域的土壤侵蚀主要由汛期的强降水引起.⑤随着小流域大面积、高标准的生态环境建设,1990年至2004年间小流域的输沙模数呈锐减之势,植被恢复与重建起到了显著的减沙效应.

Research was performed on the small watershed of the Daughter Stockaded Village, examining the changing characters of precipitation, water and sediment in vegetation recovery and rebuilding of middle and small watershed. The total decrease of sediment level in vegetation recovery and rebuilding analyzed in the paper. The results showed that： ① The obvious difference in annual amount of precipitation of small watershed by influence of air circulation. There was obvious difference in precipitation in a year, the main precipitation distributed in flood reason （April to August）, and the distribution trend of monthly precipitation almost consistence in a year. ② The obvious difference is in annual runoff in small watershed, and the obvious difference is in runoff distribution in a year. The concentrating runoff is the obvious character of the changing runoff in small watershed. There is obvious delay and subduction function for the appearance and volume of flood peak by vegetation recovery and rebuilding of small watershed.③ The main amount of runoff （Qi） is origin of precipitation（Pi）, the obvious one dimensional system is Pi= 115.7678 ＋ 2.7386Qi. ④ The annual sediment transport modulus and the changing law of runoff in small watershed is almost consistence. The sediment is concentrated with precipitation and runoff, and the soil erosion in small watershed is mainly caused by heavy precipitation. ⑤ With the large area and high standard ecological environrocnt constnaction of the small watershed, the sediment transport modulus had been obvious decreased in small watershed in 1990 to 2004. There is the obvious decrease effect of the in sediment transport in vegetation recovery and rebuilding.