潜水质量安全评价指标体系的研建:以西安为例

Establishment of Index System to Evaluate the Safety of Phreatic Water Quality:Taking Xi'an as an Example

把潜水作为被保护的目标主体,评价和研究在环境作用下潜水自身质量上的安全程度,特别突出污水入渗对潜水安全的威胁;创建了潜水质量安全评价指标体系——DRAUGHTS体系,建立了相应的计算公式。创建的潜水质量安全评价指标体系包含潜水埋深等级分量、大气降水净补给量等级分量、含水层介质的类别等级分量、渗透系数等级分量、包气带介质的类别等级分量、污水补给质量等级分量、污水补给数量等级分量以及土壤介质的类别等级分量共八大因子,其中既含有制约潜水抗污染能力的多项内在因子,又含有对潜水水质作用强度的多项外界因子,特别强化了外界对潜水水质的作用。按照潜水质量安全指数,由小到大划分出5个安全等级,从1级到5级,其安全程度由好到差。最后,以西安市平原区作为干旱半干旱地区大都市的案例,将DRAUGHTS体系应用到案例区的潜水质量安全评价研究中。结果表明:案例区的潜水质量安全程度与渗漏补给潜水的污水质量和数量密切相关,与实际情况吻合,证明创建的DRAUGHTS体系在案例区的应用是成功的,结果是可信的。该评价指标体系是可行的,可以推广应用到类似条件地区的潜水质量安全评价中。

Phreatic water was taking as the main subject to be protected, and the safety of phreatic water quality under the influence of environment was evaluated and studied, especially the threat of sewage infiltration to phreatic water safety~ an index system to evaluate the safety of phreatic water quality （DRAUGHTS system） was established, and the corresponding equation was built. DRAUGHTS system had eight evaluation factors, including buried depth of groundwater table, precipitation infiltration rate, lithological character of aquifer, hydraulic conductivity, lithological character of aeration zone, quality of sewage supply, quantity of sewage supply and soil type grade components. Some internal factors restricted the anti-pollution ability of phreatic water, and some extrinsic factors influenced the quality of phreatic water, and environment effect on phreatic water quality was emphasized especially. Safety indexes of phreatic water quality were divided into five grades from the small to the large, and when the indexes were from 1 to 5, the safety was from best to worst. Finally, taking Xi＇an as an example of the arid and semi-aridregion, DRAUGHTS system was applied to study the evaluation of phreatic water quality safety. The results showed that the safety of phreatic water quality was closely related to the quality and quantity of sewage from phreatic water percolating recharge in the case, which coincided with the actual situation; the application of DRAUGHTS system was successful, the result was believable. In general, DRAUGHTS system was feasible, and could be popularized in the similar regions.