特枯水年珠江流域东江三角洲压咸调度预演与策略

Simulation and Strategy for Salinity Control Scheduling in Dongjiang Delta of Pearl River Basin in Severe Drought Year

近些年珠江口咸潮上溯呈加剧趋势,影响范围显著增大,2021—2022年枯水期东江三角洲发生有记录以来最严重咸潮上溯。基于2021—2022年东江流域水情、工情、咸情数据,分析了东江水情特征和东江三角洲咸潮上溯规律,采用FVCOM(Finite Volume Coastal Ocean Model)数值模型开展了压咸调度预演,阐明了特枯水年下东江三角洲压咸流量、压咸时机等关键参数。研究发现:2021年,东江流域遭遇特枯水年,上游博罗断面年均流量较多年平均偏少64.5%。东江三角洲咸潮峰值发生在大潮阶段,小潮时咸潮上溯减弱。因东莞市调蓄能力较弱,东江三角洲压咸调度策略应为大潮时期全时段压咸。特枯水年下,为了应对可能出现旱情持续的更不利局面,博罗日均流量按大潮期间不低于280 m3/s、其他时间不低于212 m3/s管控,可基本保障东江三角洲供水安全。研究可为东江三角洲枯水期水量调度和咸潮防控提供一定借鉴。

In recent years,the saltwater intrusion in the Pearl River Estuary has intensified,with a significantly expanded impact range.During the dry season from 2021 to 2022,the Dongjiang Delta experienced the most severe saltwater intrusion on record.Based on the river discharge,pondage,and salinity data of the Dongjiang Basin from 2021 to 2022,this paper analyzed the hydrological characteristics and the saltwater intrusion patterns in the Dongjiang Delta.The numerical Finite Volume Coastal Ocean Model(FVCOM)was used to simulate the salinity control dispatching,and the key parameters such as the river discharge and timing of salinity control dispatching in the Dongjiang Delta in the severe drought year were explored.The research finds that the Dongjiang Basin suffered a severe drought year in 2021,with an annual average river discharge at the upstream Boluo Station being 64.5%lower than the multi-year average value.In the Dongjiang Delta,saltwater intrusion peaked during spring tides and dropped during neap tides.Due to the weak capacity of regulation and storage in Dongguan City,the strategy for salinity control dispatching in the Dongjiang Delta is to release fresh water throughout the duration of spring tides.In order to cope with the more adverse situation that the drought may continue,the average daily river discharge at the Boluo Station should be regulated to not less than 280 m3/s during the spring tides and not less than 212 m3/s during other periods.This will essentially ensure the water supply security in the Dongjiang Delta.This paper provides some reference for the river discharge dispatching and salinity control during the dry season in the Dongjiang Delta.