Effect of soil and water conservation on the runoff on the Loess Plateau

The effects of soil and water conservation measures on runoff and water balance were analyzed and formulated with the data of rainfall, runoff and the land usage condition of Xichuan River Basin since the soil and water conservation measures have been taken after 1990. The relationship between runoff coefficient and the level of soil and water conversation was presented. The results showed that the soil and water conservation measures could improve the infiltration and runoff during rainfall period and weaken the hydrological cycle on basin scale, and reinforce the hydrological cycle at field scale. The engineering measures have greater holdup of effect on runoff than those of vegetative measures. The hydrologic effects of the forestry and grassland measures have the laggard characteristics.