Groundwater Protection Rule – Nitrogen Fertilizer


Groundwater springs are the lifeblood of our trout streams.  Trout depend upon a steady supply of cold groundwater to keep streams cool enough in summer, and warm enough in winter.  Whether large springs or small seeps, every trout stream relies upon vital inputs of groundwater.


In recent decades the rising demand for permits to remove groundwater from our aquifers has outstripped the finite supply.  Once viewed as limitless, and still mistakenly viewed this way by some, many aquifers are being depleted by excessive and unsustainable pumping.  As aquifer levels drop, the volume of natural springs entering trout streams begins to decrease.  Where unsustainable pumping continues, eventually too little groundwater remains in the aquifers to supply trout streams with the minimal base flow required to support trout and other aquatic life.  For this reason, wild trout are a good indicator of the health and sustainability of our groundwater systems.  Trout are recognized by informed individuals as finny versions of “canaries in a coal mine”, which can warn us of dangerous changes occurring underground.  Minnesota Trout Unlimited continues to fight back threats to sustainable use of groundwater.


In addition to groundwater quantity, pollution of groundwater quality can damage trout, aquatic insects and other aquatic life, not to mention human health.  Elevated levels of nitrate are of particular concern.  Trout streams, because they are so closely tied to groundwater are protected by the same federal drinking water standard of 10 milligrams per liter (10 mg/l).  The Minnesota Pollution Control Agency is still working to develop a water quality standard protective of aquatic life in streams and lakes, but scientific studies suggest that a chronic value (4 day duration) of less than 5 mg/L nitrate is needed for protection of aquatic life in coldwater (trout) streams and lakes.



Attack on Groundwater Protection ActAction Needed April 16, 2018

Bills which would block adoption of a nitrogen fertilizer rule by the MN Department of Agriculture are being heard in the House and Senate on Monday April 16.  Calls and emails needed! Read our blog HERE.