Changes

* U.S. EPA (2002). [https://nepis.epa.gov/Exe/ZyNET.exe/P10053D9.TXT?ZyActionD=ZyDocument&Client=EPA&Index=2000+Thru+2005&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYear=&QFieldMonth=&QFieldDay=&IntQFieldOp=0&ExtQFieldOp=0&XmlQuery=&File=D%3A%5Czyfiles%5CIndex%20Data%5C00thru05%5CTxt%5C00000021%5CP10053D9.txt&User=ANONYMOUS&Password=anonymous&SortMethod=h%7C-&MaximumDocuments=1&FuzzyDegree=0&ImageQuality=r75g8/r75g8/x150y150g16/i425&Display=hpfr&DefSeekPage=x&SearchBack=ZyActionL&Back=ZyActionS&BackDesc=Results%20page&MaximumPages=1&ZyEntry=1&SeekPage=x&ZyPURL Collection Systems Technology Fact Sheet]. Sewers, Conventional Gravity. 832-F-02-007. U.S. Environmental Protection Agency, Washington, D.C., US. (Good description of the technology, including more detailed design criteria and information on operation and maintenance)

===Acknowledgements===

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