Construction of dam system has close relation with control of slope. Control of slope has the effect of retaining and blocking flood, and can lessen the amount of dams and reservoirs, the height of each single dam necessary for relative stability of dam system, then reduce engineering scale of dam system, shorten the time of dam system to reach relative stability and increase the use rate and stable yield ensuring rate of dam system.
The paper analyused the law of annual variation of dam land area and food harvest ratewith different composition of soil-saving dam,and put forward the method of determining initial use,year of dam land . Furthermore,this paper ascertained the formula of calculating economic benefit of soil-saving dam by means dynamic economic method,and presented the calculating example.
Taking the effects of deepth of drowning water, drowning duration and thickness of silted sediment on crop yield into consideration, this paper holds that the standard of flood control and production security of damland in high coarse sediment area should be 5 % flood probability and 80 % crop harvest security.
Based on benefit analysis of single warping dam,a mathematic model for designing dam height was established, taking the maximal economic benefit of single dam as object function.