基于潮汐时变特征的水质时空双重达标控制标准

潮汐河口水文、水质要素具有日内、月相周期性的时变特征,不适用恒定流的计算方法和评价标准进行水质达标控制,从而无法科学核定河口的水环境容量用于水污染防治管理。本文针对潮汐河口的非恒定往复流特性及水质的时变特征,提出了适用于潮汐河口水质达标控制的时、空双重控制标准;建立了钱塘江河口潮流水质模型,基于水质时空双重达标控制标准核定了各水功能区的环境容量。其中时间控制标准采用1d内超标小时数和月内超标天数两个指标控制,空间控制标准采用功能区空间平均水质、交界断面水质、混合区面积和敏感点水质等4项控制指标进行控制。水质时、空双重控制标准能够更全面更真实的反映潮汐河口水质达标情况,从而有效保护河口水资源水环境质量。其计算思路和方法可供相关水环境研究人员和环境管理人员借鉴。

Timing and spacing double water quality control criterion based on tidal time-varying characteristics

As to tidal estuary hydrology and water quality elements have period time-varying characteristics in a day and a month, the computing method and evaluating standard for steady flow is not suitable for tidal estuary to control the water quality up to standards, so it cannot scientific verify the water environmental capacity for water pollution prevention and management. This paper aimed at tidal estuary unsteady reciprocating flow and time-varying water quality characteristics, proposed the timing and spacing double water quality control criterion, and then verified the environmental capacity of each functional area based on Qiantang estuary tidal water quality mathematical model. Time control criterion used two indexes to control which are the number of hours in a day and the number of days in a month of which water quality exceeds standard; space control criterion adopted four indexes to control which are average water quality of functional areas, water quality of cross sections, area of mixing zones and water quality of sensitive points. The water quality timing and spacing double control criterion can more comprehensively and truly reflect the status of water quality reach the standard of tidal estuary, so can effectively protect the tidal estuary water resources and water environment quality. The computation thoughts and methods can be referenced by environmental researchers and managers.