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NEMO Nevada (Nonpoint Education for Municipal Officials)

NEMO Photo Gallery

The Problem: Nonpoint Source Pollution?

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Photo by S. Donaldson
NPS, or nonpoint source pollution, comes from a variety of sources. In this and the following photo, rain from a summer cloudburst is flushing pollutants down the storm drain. The pollutants are not just those that have accumulated on the pavement of the parking lot, but also sediment that has eroded from adjacent bare soils.
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Photo by S. Donaldson
 
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Photo by J. Cobourn
Storm drains discharge storm water directly into our local water bodies, with no treatment.
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Photo by UCONN Cooperative Extension-NEMO
NPS can be divided into six major categories. Perhaps the easiest to recognize and understand is debris or trash.
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Photo by UCONN Cooperative Extension-NEMO
Debris is unsightly, and as it decomposes, it can be a source of toxic contaminants.
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Photo by S. Donaldson
Nutrients are substances needed for plant growth, most commonly nitrogen and phosphorus. Excess nutrients in the water results in algae blooms. When the algae dies and decays, it consumes the oxygen in the water, causing fish kills.
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Photo by UCONN Cooperative Extension-NEMO
The fourth category is sediment. Sediment is soil, sand or gravel that has been picked up and moved, usually by water. Sources include new construction sites, poorly constructed sites, bare, unstabilized slopes, and agricultural fields.
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Photo by M. Hefner
In the next two photos, construction of a new home has resulted in exposed, easily eroded soil. After it rains, the soil is washed to the gutter and into the storm drain. The soil shown here came from a single home site.
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Photo by M. Hefner
 
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Photo by H. Segale
This photo of Lake Tahoe shows sediment plumes entering the water carried by storm water runoff after a flood. Nutrients such as phosphorus attach to soil particles, so the sediment is also a source of nutrient pollution.
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Photo by UCONN Cooperative Extension-NEMO
We have all seen the iridescent sheen of hydrocarbons such as oil and gas in parking lots after a rainfall. These substances are in the category referred to as toxic chemicals.
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Photo by Snohomish County Washington Public Works
The next two photos show examples of toxic chemicals being washed into local water bodies by storm water runoff.
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Photo by Snohomish County Washington Public Works
Toxic chemicals include a wide variety of industrial and home chemicals. When misused, these substances may be washed into local water bodies via the storm drain system.
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Photo by Snohomish County Washington Public Works
Both the illegally vented sewage and the happy hog below are sources of pathogens. Pathogens are disease-causing bacteria and viruses associated with the fecal matter of humans and animals. Other sources include failing septic systems and broken sewage pipes.
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Photo by FISRWG
 
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Pathogen pollution may result in beach closures and fishing bans.
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Photo by J. Cobourn
The sixth type of NPS pollutant is thermal stress, or hot water. This photo of Steamboat Creek shows creek banks with very little vegetative cover. The lack of shade allows the shallow water to get hot quickly. Paved parking lots that absorb heat and transfer it to rainfall or irrigation