摘要:
西南岩溶区的地下河数量及总流量是有关职能部门和专业技术人员关心的两个重要数据。20世纪80年代对西南6省进行统计,结果为2836条,流量1482 m3/s;20世纪90年代对西南8省进行统计,并经过近年的数据库校核为2523条,总流量1321.7 m3/s;其中流量大于2000 L/s 有120条,合计流量699.7 m3/s,占总流量的52.94%;流量在50~500 L/s 地下河最多,有1 311条,占总数的5 1.55%,其次为流量小于50 L/s 的有723条,占总数的28.43%。文章针对上述统计方法存在岩溶地下河流量重复统计、与岩溶大泉流量交叉重复统计两种问题,以大小井和寨底地下河系统为例,给出了具体重复统计量。基于1∶20万水文地质普查资料,大小井和寨底地下河重复统计量分别占总出口流量的57.1%、7.1%;而基于最新调查资料,重复统计量则分别可增加到134.3%,86.1%。因此,随着1∶5万水文地质调查面积越多,所发现的地下河出口越多,按传统的统计方法其重复统计量则越大。引起上述重复统计问题主要原因是把地下河系统和子系统混合在一起。文章最后讨论了地下河系统的空间属性,提出避免重复统计措施,对西南岩溶区地下河流量正确统计以及具有相同特征的岩溶大泉流量统计有一定指导意义。
Abstract:
In the karst areas of eight provinces in southwestern of China,the number of underground river and their total discharge are two important parameters that draw mauch attention.The statistics in the 1 980s yielded 2 836 underground rivers and total discharge 1 482 m3/s.Whereas in the 1 990s,the statistics for all the 8 provinces,corrected by the database in recent years,shows that there are 2 523 underground rivers with total discharge about 1 321.7 m3/s.Of them,there are 120 underground rivers with single discharge more than 2 000 m3 L/s,and their discharge sums 699.7 m3/s accounting for 52.94% of the total.The un-derground rivers with discharge between 50 -500 L/s is the most,occupying 5 1.55% of the total;next is those less than 50 m3 L/s which is 723 in number and accounts for 22.43% of the total.This paper points out that the statistics above are problematic with over-estimation in karst underground river discharge and large-discharge karst springs.Taking two examples of the Daxiaojing and Zhaidi underground river systems,this paper presents the specific amount of double counting.Based on the old 1 ∶200 000 hydrogeological survey data,the total re-statistics account for 57.1% and 7.1% separately for the total outlet discharge of the Daxi-aojing and Zhaidi river systems,respectively.While these values can be increased separately to 134.3% and 86.1% using the latest survey data.It can concluded further that with increasing coverage of 1 ∶ 50 000 hydrogeological surveys,more outlets will be counted,the amount of the bouble counting by the traditional methods will be greater.The primary reason for such an overestimation problem lies in mess of the under-ground river system and sub-system.Finally,this paper discusses the spatial attributes of karst underground river systems and proposes countermeasures to metigatye the problem of double counting.It would help es-tablish realistic statistics of discharge of underground rivers and major springs of karst areas in southwestern China.
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