【摘要】 运用河口湿地来削减氮磷入海通量 ,防止近海水体富营养化。首先对辽河三角洲湿地净化系统进行了理论分析 ,并建立了相应的概念模型 ,然后依靠野外实验数据 ,为湿地的营养物去除功能建立了一个空间模型。该模型包括两大部分 :一是灌渠子系统 ,二是苇田子系统。前者使用的是一个非线性回归模型 ,后者则是以百分率为基础的简单模型。该模型在个别灌区试运行后 ,推广到整个苇田研究区更多还原

【Abstract】 The eutrophication problem of coastal seawater has been a serious hazard in the last two decades in Eastern China.This problem is mainly caused by the nutrients like nitrogen and phosphorous from inland non\|point sources.The purification function of natural wetlands at big river deltas provides a potential solution to cut down nutrient input into the sea.The objective of this research is to develop a model to simulate the ability of nutrient reduction in the wetland system so as to evaluate to what extent the natural wetland can be used as a treatment system for nutrient enriched river water.The study area is in the Liaohe Delta,China,where the world largest reed marsh is located.The natural wetland is a multi\|functional landscape in biomass production and protection,water regulation,soil formation,coastline stabilization and pollutant purification.The reed and canal system has a high reduction rate for many pollutants such as COD,nitrogen and phosphorous.Besides,the reed marsh can also be used as a treatment system for oil drilling water.Therefore,wastewater irrigation in the reed field should be encouraged to solve the water shortage problem in spring,increase reed productivity and prevent coastal pollution.\;Based on the field data collected during 1997～1998,spatial models are designed on a stepwise basis to simulate the nutrient reduction function of the wetland in the Liaohe Delta.A series of analytical models are established to describe the whole process from water input into the system to output into the sea.The general model gives an overview of the system.The conceptual model incorporates the main objects and factors into the system and gives a brief description of the main processes.The data model translates the conceptual model into a workable system that can be realized within GIS.The simulation model contains two major subsystems:the canal system and the reed field.In the preliminary model,a non\|linear regression model is established for the nutrient reducion in the canal system:C (x,y) =-A× ln (dist.)+B\ (A>0,B>0)Where C(x,y) is the nutrient concentration value(in mg/l)of a canal point at a certain distance(dist.)to the pumping station. A and B are linearly related to the nutrient input concentration (inload in mg/l) at the pumping station:A=C 1× inload +C 2 (R 2 N=0.87,R 2 P=0.95,n=24) B=C 3× inload +C 4 (R 2 N=0.78,R 2 P=0.89,n=24)The values from C1 to C4 are obtained for nitrogen and phosphorous according to the retgression of field experimental data.\;On the other hand,the process model used for the reed field part is rather simple.Only a percentage based reduction model is adopted due to lack of field data.In order to be able to make predictions for the total nutrient reduction of the whole reed covered area,water data must be incorporated into the model.Further improvement of the model will be done in the second part of this paper.更多还原