热分层对水库水质的季节性影响-以西安黑河水库为例

J．LakeSci．(湖泊科学)，2014，26(5):698-706http://www．jlakes．org．E-mail:jlakes@niglas．ac．cn2014byJournalofLakeSciences热分层对水库水质的季节性影响———以西安黑河水库为例*卢金锁，李志龙(西安建筑科技大学环境与市政工程学院，西安710055)摘要:深水水库作为城市的重要供水水源，通常由于热量在垂向水体上的不均匀分配形成热分层．热分层会阻碍垂向上水体交换引发水质分层现象，在冬季水库发生“翻库”之后，水体混合导致水库的整体水质下降．结合热分层指数可以客观、直接地表达水库热分层的稳定程度．综合水库的气温、水体更新率和水质参数(溶解氧、pH、总磷、氨氮)的年度变化，对陕西黑河水库20082010年的热分层状况进行研究．研究表明:水库的热分层形成会直接恶化底部水质尤其会加速底部水体中溶解氧的消耗;热分层的年度变化主要受气温控制，但在特定时期较大的水体更新率可以在一定程度上弱化水体热分层，减缓底部水质恶化．该结果可使水库管理者在水库分层最稳定、水质恶化最严重时期以人工调节水体更新率的方式弱化热分层，为保证水质安全提供参考．关键词:深水水库;黑河水库;热分层指数;溶解氧;水体更新率Seasonaleffectsofthermalstratificationonthewaterqualityofdeepreservoirs:AcasestudyofHeiheＲeservoir，Xi'anCityLUJinsuo＆LIZhilong(SchoolofEnvironmentalandMunicipalEngineering，Xi'anUniversityofArchitectureandTechnology，Xi'an710055，P．Ｒ．China)Abstract:Asamajorsourceofwatersupplyforcities，deepreservoirsusuallyformthermalstratificationduetotheunevenverticalheatdistribution．Thermalstratificationcanhindertheverticalwaterexchange，thuscausewaterqualitystratification．Inwinter，thewatermixingcausedbythe“turnover”ofareservoirleadstothedeteriorationofoverallwaterquality．Withtheapplicationofthermalstratificationindex，thereservoirthermalstratificationstabilitycanbeobjectivelyanddirectlyexpressed．Integratedwiththeannualchangesofreservoirtemperature，waterrenewalrateandwaterqualityparameters(dissolvedoxygen，pH，totalphos-phorous，ammonianitrogen)，thispaperstudiedthethermalstratificationconditionsofHeiheＲeservoir，ShanxiProvince，in2008-2010．Studiesshowedthattheformationofthethermalstratificationcoulddirectlydeterioratethewaterqualityandparticularlyac-celeratetheconsumptionofdissolvedoxygen，inthebottomwater．Althoughannualchangesofthermalstratificationaremainlycontrolledbythetemperature，atcertainperiodsthehigherwaterrenewalratecanweakenthethermalstratificationtosomeextent，andmitigatethedeteriorationofthebottomwaterquality．Theresultsshowthatduringtheperiodsofthemoststablethermalstrati-ficationmanagersofthemostseriousdeterioratingwaterqualityreservoirscanmanually