BMP stands for Best Management Practices and has become public works jargon for good storm water management.
Effluent is typically waste water or sewage, though it literally means anything flowing out. http://water.epa.gov/scitech/wastetech/guide/index.cfm
"Nonpoint source" is defined to mean any source of water pollution that does not meet the legal definition of "point source" in section 502(14) of the Clean Water Act. NPS pollution is caused by rainfall or snowmelt moving over and through the ground... As the runoff moves, it picks up and carries away natural and human-made pollutants.” http://water.epa.gov/polwaste/nps/whatis.cfm
“Point source" means any discernible, confined and discrete conveyance, including but not limited to any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation, or vessel or other floating craft, from which pollutants are or may be discharged.” Section 502(14) of the Clean Water Act
Tailwater occurs when storm water in pipes and ditches encounters seawater, particularly at high tide or during storm surge. http://www.wetlandswatch.org/sea_level/norfolk_city_flooding_pres_2010.pdf
Total Maximum Daily Load (TMDL) gives the hard limits on how much nitrogen, phosphorus and sediment will be allowed in the Chesapeake Bay in the EPA’s “pollution diet.”