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Fall 1995 |
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Page 5 |
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Inside |
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The Sanctuary's Watersheds |
pg. 5 |
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The Floods of 1995 |
pg. 5 |
For residents of the Monterey Bay area, the winter of 1995 will be hard to forget. Record rainfall in March brought floods which affected 75,000 acres of farmland, washed away bridges, inundated sewage plants, and devastated neighborhoods. What effect did the flood have on the Sanctuary's water quality?
According to Patrick Cotter, Sanctuary Environmental Scientist, "The Sanctuary is the receiving end of everything that flows down the rivers... The biggest immediate concern of the Sanctuary was the raw sewage flowing into rivers due to the loss of production at wastewater treatment plants. Untreated wastewater has all sorts of contaminants in it&emdash;solids, bacteria, organic chemicals, heavy metals...[Another concern] was the topsoil washing off agricultural fields and sediment deposition in Monterey Bay. Fine sediments contain many pesticides such as DDT, chlordane, and other persistent chemicals used in the past and banned today. Sediments washed down the rivers may contain these pesticides. When river water flows into the Sanctuary, these sediments settle on the bottom on Monterey Bay.
From sediment samples taken on the McArthur cruise soon after the flood, scientists were able to detect a fine layer of newly deposited topsoil in the ocean between two and five miles offshore. In addition to sediment, the rivers carried larger debris into the Sanctuary. It could have been far worse, however. The EPA Emergency Response Team found only a small amount of hazardous material, like paint buckets and gas cans, had washed ashore in the Sanctuary after the flooding.
Although there is no ongoing study to assess the flood's
effect on the Sanctuary, the event will be a benchmark for
future research. Much has been learned already. In future
emergencies, the Sanctuary will be linked with the Office of
Emergency Services in Monterey County so it can be informed
of threats to the Sanctuary as they happen. According to
Holly Price, "The flood should provide an impetus to looking
at watersheds as a whole. We need to find better ways to
manage our soils, rivers and wetlands to handle floods while
protecting the natural resources in the watersheds. There's
a lot of overlap between flooding and water quality issues."
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The quality of the water in the Sanctuary is ultimately linked to the quality of the water that drains into it from its adjacent 350 miles of coastline. All of the mountains and valleys on the map below receive rainfall and irrigation water, which runs downhill to streams, rivers, wetlands, and eventually out to the ocean. While this water is moving downhill, it picks up a variety of pollutants which are carried with the water and may ultimately affect Sanctuary resources. This drainage area is called a watershed &emdash; from the tops of the mountains, down to the creek and out to the ocean. Eleven major watersheds (containing over 50 rivers, creeks and estuaries) drain directly to the Sanctuary (see map). These watersheds vary greatly, from the relatively pristine conditions of the Big Sur Coast to the heavily farmed watersheds of the Pajaro, the steep agricultural lands surrounding Elkhorn Slough, and, of course, our largest watershed, the Salinas Valley, with its billion dollar agricultural industry. The Sanctuary also has urbanized watersheds, such as the small communities in Carmel Valley and the North Coast, and the densely populated cities of the Monterey Peninsula. At estuaries, such as Elkhorn Slough, and river mouths, such as the Salinas River, watersheds and the waters of the Sanctuary actually tie together. |
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Last modified on: June 14,
1999