Input Response Model’s Construction And Study On Change’s Sensitivity Of Water Quality Of Second Songhua River’s Trans-boundary Section

In recent years, with economic development, population’growth and improvedliving standards, a large amount of industrial wastewater and domestic sewage hasflowed into the water basin, causing serious pollution to the water environment. Atthe same time trans-boundary water pollution problems and trans-boundary pollutiondisputes often occur, which seriously affects basin downstream sustainable economyand society development and people’s living standards. Therefore, The trans-boundarysection water pollution control and governance has drawn increasing attention of therelevant departments.Based on pollution characteristics of the main section in researched river,analysis of impact factor of water quality in Songlin Section, input response principleand the principle of conservation of mass, using one-dimensional steady-state riverwater quality model and Kara Wu She fu reservoir model, this paper establishes amulti-river water quality model—input response model,which illustrates the effect ofupstream runoff, discharge along the river, Yinma River’ tributaries, groundwaterrecharge and Hadashan impoundment on Songlin Section of the Second SonghuaRiver. What’s more, this paper simulates COD concentration of2010,2011and2012,compared with the historical monitoring data,error is small. Therefore, that modelcan be used to simulate Songlin Section’ water quality of the second Songhua River.Using constructed input response model,this paper researches on the contribution ofwater quality factors on COD concentration of Songlin Section and researches onchanges of COD concentration on sensitivity of changes in water quality,waterquantity, storage capacity and other changes, eventually this paper provides ascientific basis for water pollution control and management in Songlin Section. Based on the analysis, PH, dissolved oxygen, selenium and fluoride do notexceed standard in White Flag, Songhua River Station and Songlin Section, althoughCOD, CODMnand BOD5do not exceed standard, the pollution is very serious. Inaddition, the absolute value of comprehensive weight coefficients of PH, COD andfluoride are large, which are the main environmental factors of water quality inSonglin Section. According to contribution rate of each factor in wet season, normalseason and dry season, the difference of relative contribution rate of the same factorsat different water season is large, which shows that each factor’ contribution rate toCOD concentration in Songlin Section is not only relevant to water quality itself andwater quantity but also to the overall amount of water in river. According to thesensitivity of changes in water quality to changes of each factor in Songlin Section,the sensitivity of water quality changes in section to upstream runoff water’ qualityand quantity changes is relative high in wet season, normal season and dry season. Inaddition, controlling water quality of Yinma tributaries, water quality of groundwaterrecharge and regulation of Hadashan reservoir storage is also crucial.