TMDL_2010August

Impaired Waters : 

Impaired Waters Waters are classified as impaired when they fail to meet state water quality standards and have been placed on the federal impaired waters list 303(d)

Slide 3: 

Lake Studies

Total Maximum Daily Load(TMDL) : 

Total Maximum Daily Load(TMDL) A Total Maximum Daily Load study must be conducted for lakes, streams and rivers that have been listed as impaired. Total Maximum Daily Load is the extent to which a body of water is able to assimilate or tolerate a pollutant and still maintain its water quality standards. Lake Studies

TMDL Analysis : 

TMDL Analysis A TMDL is the sum of the individual waste loads from point sources, nonpoint sources and natural background, with an additional loading allowance for a margin of safety. This is generally described by the following equation… Lake Studies

TMDL (AC) = WLA+LA+MOS : 

TMDL (AC) = WLA+LA+MOS Where: AC = Assimilative Capacity of the water body to achieve/maintain standards WLA = Waste Load Allocation, quantification of pollutant loads from point sources discharging to the water body LA= Load Allocation, quantification of pollutant loads from nonpoint sources MOS = Margin of Safety, reflects uncertainty in the analysis, a desire to provide an extra margin of protection for beneficial uses, or an allowance for future growth Lake Studies

Impairments for Excess Nutrients : 

Impairments for Excess Nutrients Data must show exceedances of two of the following three standards 1. Total Phosphorus (causal factor) 2. Chlorophyll- a (response variable) 3. Secchi disk (response variable) Lake Studies

WQ Standards (Northern Glaciated Plains) : 

WQ Standards (Northern Glaciated Plains)

WQ Standards (North Central Hardwood Forest) : 

WQ Standards (North Central Hardwood Forest)

Slide 10: 

Lake Water Quality Lake Studies

Why require phosphorus control? : 

Why require phosphorus control? Phosphorus is the limiting nutrient for algal growth in most Minnesota lakes and streams Other limiting factors such as sunlight and temperature cannot be controlled in a lake or stream Lake Studies

Phosphorus = Algae : 

Phosphorus = Algae Lake Studies

Slide 13: 

P P P P P P Sources of phosphorous Lake Studies

Phosphorus Cycle : 

Phosphorus Cycle Lake Studies

Phosphorus reductions needed to meet WQ standard : 

Lake Studies Phosphorus reductions needed to meet WQ standard

Slide 16: 

Lake Studies Lake Leven P Inventory

Slide 17: 

Lake Studies Gilchrist Lake P Inventory

Slide 18: 

Lake Studies Anne Lake External P Inventory

Slide 19: 

Lake Studies Reno P Inventory

Malmedal P Inventory : 

Lake Studies Malmedal P Inventory

Slide 21: 

Lake Studies Strandness P Inventory

Slide 22: 

Lake Studies Pelican Lake P Inventory

Slide 23: 

Lake Studies Lake Emily External P Inventory

Impaired Waters : 

Impaired Waters Lake Studies Tim JamesMinnesota Pollution Controltim.james@state.mn.us 218-846-8103