广州市帽峰山两种主要林型的暴雨水文特征

Hydrological Features of Rainstorms in Two Forest Types in Maofeng Mountain of Guangzhou

为了探索不同森林类型暴雨水文特征的差异,于2013年12月—2014年12月,在暴雨条件下对广州市帽峰山杉木林和常绿阔叶林的林外降水、穿透水、地表径流和集水区总径流进行水文量与水化学量的对比测定。结果表明,(1)2014年发生9场暴雨,暴雨雨量为655.0 mm,占全年降雨量(1 882.4 mm)的34.8%。(2)杉木林林冠层对暴雨的平均截留率为8.2%,集水区暴雨日的平均产流率为19.1%;常绿阔叶林冠层对暴雨的平均截留率为14.5%,集水区暴雨日的平均产流率为21.2%。(3)杉木林集水区全年产流714.8 mm,产流率为38.0%,其中雨季的产流率为44.4%,雨季产流量占全年的98.1%;常绿阔叶林集水区全年产流802.0 mm,产流率为42.6%,其中雨季的产流率为44.6%,雨季产流量占全年的87.9%;体现了常绿阔叶林对全年降雨的调蓄作用更大。(4)两种林分的冠层淋溶都表现为正淋溶,杉木林和常绿阔叶林穿透水的淋溶系数均以K最大,分别为4.10和7.88。(5)两种林分地表径流的化学含量显著高于降雨,地表径流中增加最小的N含量为降水的3.03倍,增加最大的Ca含量为降水的14.25倍,说明暴雨形成的地表产流是森林生态系统养分流失的重要原因。两种林分集水区总径流中C、NH_4^+-N和P的迁移系数为负值,表现为吸储效应。

The paper explored the hydrological features of the rainstorms in two forest types:Chinese fir(Cunninghamia lanceolata)forest and evergreen broadleaf forest in Maofeng Mountain of Guangzhou.Hydrological amounts and chemical concentrations in therainfall,throughfall,surface runoff and catchments runoff were monitored from December2013to December2014.The resultsshowed that:(1)Rainfall from nine rainstorm(655.0mm)accounted for34.8%of the total rainfall(1882.4mm)of the year.(2)Forthe Chinese fir forest,the average interception rate of the canopy was8.2%,and the average runoff rate of catchments was19.1%.Bycomparison,the average interception rate of the canopy of evergreen broadleaf forest was14.5%,and the rainstorm average runoffrate of catchments was21.2%.(3)The annual runoff of Chinese fir forest catchments was714.8mm with an annual runoff rate of38.0%.The runoff in the rainy season makes up98.1%of the total runoff of the year with a runoff rate of44.4%in the rainy season.The annual runoff of evergreen broadleaf forest catchments was802.0mm with an annual runoff rate of42.6%.In the rainy season,the runoff rate was44.6%,and the runoff was accounted for87.9%of the annual value.This result indicated that broadleaf forest hasa stronger impact on the annual rainfall compared with the Chinese fir forest.(4)Both types of forest displayed the positive canopyleaching,the maximum canopy leaching coefficients were for K,which were4.10and7.88for Chinese fir forest and evergreenbroadleaf forest respectively by.And(5)chemical concentrations of surface runoff were significantly higher than rainfall.Chemicalconcentration of N in runoff was3.03times of that in rainfall,while Ca in runoff can be as high as14.25times that in rainfall.Thisimplied that the most significant nutrient loss in forest ecological system was from the surface runoff during the rainstorms.Themigration coefficients of C,NH4+-N and P in two types of forest catchments total-runoff were negative due to the absorption effects.