1.1 	A bill for an act
1.2 	relating to environment; modifying Clean Water Legacy Act;amending Minnesota 
1.3 	Statutes 2018, section 114D.15, subdivision 10.
1.4 	BE IT ENACTED BY THE LEGISLATURE OF THE STATE OF MINNESOTA:

1.5 	Section 1. Minnesota Statutes 2018, section 114D.15, subdivision 10, is amended to read:
1.6 		Subd. 10.Total maximum daily load or TMDL. "Total maximum daily load" or 
1.7 	"TMDL" means a scientific study that contains a calculation of the maximum amount of a 
1.8 	pollutant that may be introduced into a surface water and still ensure that applicable water 
1.9 	quality standards for that water are restored and maintained. A TMDL also is the sum of 
1.10 	the pollutant load allocations for all sources of the pollutant, including a wasteload allocation 
1.11 	for point sources, a load allocation for nonpoint sources and, a load allocation for natural 
1.12 	background, an allocation for future growth of point and nonpoint sources, and a margin of 
1.13 	safety to account for uncertainty about the relationship between pollutant loads and the 
1.14 	quality of the receiving surface water. "Natural background" means characteristics of the 
1.15 	water body resulting from the multiplicity of factors in nature, including climate and 
1.16 	ecosystem dynamics, that affect the physical, chemical, or biological conditions in a water 
1.17 	body, but does not include measurable and distinguishable pollution that is attributable to 
1.18 	human activity or influence. A TMDL must take into account seasonal variations.