Resources for Meteorologists
Video Links
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| Event | Description | Event Dates | Video Links |
Late Winter/ Spring Conductivity – salt in streams |
Conductivity is a measure of dissolved salts in streams. Conductivity is affected by many things: geology, agricultural, atmospheric inputs, but in urban environments, road salt is one of the key factors. “Spikes” in conductivity often occur during snowmelt or early spring rains, and can have significant impacts on fish and other aquatic organisms. A value of 960 (uS) is the chronic toxicity threshold for brook trout | 1/29/2009 2/17/2009 3/18/2009
12/26/2009 2/4/2010 2/25/2010 |
Tischer |
Summer Temperature impacts to coldwater streams |
Warm summer temperatures can be lethal for brook trout, which have an optimal range of 52-61 F (10-15 C). These graphs show two-week series where afternoon temperatures exceeded the lethal limit of 75 F. The trout probably ‘escaped’ to cooler waters, but such temperatures do stress the local trout populations. | 7/9/2006 7/25/2008 6/30/2010 |
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| Turbidity – Measuring the muddiness of streams | Turbidity is a water quality parameter that refers to how clear the water is. The greater the amount of total suspended solids (TSS; also called total suspended sediment) in the water, the murkier it appears and the higher the measured turbidity. Clay, silt, and sand from soils, phytoplankton (suspended algae), bits of decaying vegetation, industrial wastes and sewage are common suspended solids. Increased turbidity affects a stream and the organisms that live in it in many ways and if the water becomes too turbid, it loses the ability to support a wide variety of plants. It can reduces habitat for fish spawning, reduce their ability to see prey, and clog gills. |
7/18/2009 8/20/2009 |
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| Water main breaks | Duluth averages approximately 150 water main breaks per year, and under certain weather conditions, can have 4 or more breaks in a day. Half of Duluth’s 400 miles of water mains are over 80 years old, and refitting water mains will be a significant investment in the future. These video clips show the response of streams to water main breaks in 2009 |
10/5/2009 |
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