Chloride Levels in the Wingra Watershed
By: Mollie Roach, Nicole Newman, Jenny Gilles, Julie Brania
(From http://www.merlin-net.com)
We measured chloride levels of the Edgewood College Retention Pond and Lake Wingra over a five month period (October-March), paying close attention to the levels in both bodies of water after they thawed. We predicted that chloride levels in both areas would rise over the winter as a result of salt use.
We tested each site approximately once every ten days, as well as after every significant rain or snow fall. Throughout our project we collected samples from specific sites of the Retention Pond and Lake Wingra. We tested the chloride levels of both bodies of water using the Hach test kit and summarized results.
Chloride levels in both the Edgewood College Retention Pond and Lake Wingra increased over the winter. The greatest increase appeared in the Retention Pond after it began to thaw in February. We attributed these very high levels of chloride in the pond to salt used to deice campus and neighboring roads. We also believe that higher chloride levels on specific dates in the retention pond could have been caused by melting events in warm weather, by rainfall, which would have washed the salt into the pond as well as by evaporation of water from the pond, which would result in a greater concentration of chloride.
Iceban- It is an organic liquid made from agricultural by-products.
Advantages- It is a non-corrosive and depresses the freezing point of water. It can also be applied more sparsely.
Disadvantages- It is more expensive then NaCl
Sand or Cinder- Can increase traction
Advantages- It is less expensive. It helps reduce the undesirable environmental consequences.
Disadvantages- Large amounts will clog sewers and drains. Some areas of ice did not melt with sand. Applying sand over and over on roads can create a real problem.
Pre-mix- A 4 to 1 mixture of sodium chloride and calcium chloride.
Advantages: Saving on environmental costs.
Calcium Magnesium Acetate- It is an alternative to road salt in deicing operations.
Advantages- Harmless to plants and animals.
Disadvantages: Can clog spreading equipment; acts more slowly and is less effective then salt in cold conditions.