太行山片麻岩山地生态工程综合效益评价

APPRAISAL OF COMPREHENSIVE BENEFIT OF ECOLOGICAL ENGINNERING IN THE GNEISS MOUNTAINOUS REGION OF TAIHANG

通过对太行山片麻岩区生态工程综合评价认为，生态工程具有较高的保水效益，保水率可达６０％～９３％，以隔坡梯田最高，最大保水量相当于４４０．４ｍｍ的降水；生态工程可防止土壤侵蚀，使土壤侵蚀模数减少到１８４．２～３６１．２ｔ／（ｈｍ￣２·ａ），相当于荒坡的１／１６～１／７；生态工程可使洪水历时减少７０％，洪峰最大流量减小８０％，从而使下部农田免受损失，损失率减少９８％以上。山地生态工程的直接经济效益为４０００元／ｈｍ￣２以上，间接可计算经济效益３７７５．２３元／ｈｍ￣２，合计为７７７５．２３元ｈｍ￣２以上。此外，生态工程促进了山区农民的脱贫致富及荒山绿化，在大灾之年成了山区农民的“保命工程”，具有显著的社会效益。

Comprehensive appraisal of ecological engineering in the gneiss mountainous re-gion of Taihang showed that the water-holding benefit of ecological engineering is high,the rate of water-holding is 60%～93%.The water holding benefit of terraced andtrenched fleld on sloped is the highest,corresponding to 440.4mm of rainfall.Ecological en-gineering can prevent soil erosion,the soil erosive modulus decreases to 164.2～361. 2t/hm2·a),equal to 1/16～1/7 of the soil erosive modulus of slope land,the du-ration of flood decreases by 70%,the maximum flood peak by 80%,and the rate offarmland loss by flood by over 98%.The direct beneflt of ecological enginecring in moun-tainous region is more than 4000 vuan/hm2,the indirect benefit that can be calculated is3775.23 vuan/hm2,it amounts to 7775.23 Yuan/hm2.In addition,ecological engineeringhas helped mountainous farmers get rid of poverty.It is a life guard engineering for themin calamitous years.Therefore,it has a high soical benefit.