The South Fork Merced River

July 15, 2014 Posted by: KL - Park Ranger (Wawona)
Water flows over rocks on the South Fork Merced RiverIf you have ever spent time in Wawona, chances are you have fond memories of splashing around in one of the area’s many marvelous swimming holes, or spending a lazy afternoon reading a book with your feet in the water. Here in Wawona, we are lucky to be located along the South Fork Merced River, which not only offers many great places to swim, but also serves as the main source of our drinking water. The South Fork originates high in the eastern Sierra Nevada before flowing southwest through the Yosemite wilderness, into Wawona, and over the park’s western boundary through Sierra National Forest, until to it joins the main fork of the Merced River west of El Portal.

Like the main stem of the Merced River, the South Fork is a Congressionally designated Wild and Scenic River, which means that it enjoys the protection of the Wild and Scenic Rivers Act. This legislation was created to “preserve certain rivers with outstanding natural, cultural, and recreational values in a free-flowing condition." One important feature of the South Fork watershed, along with its many wild and recreational values, is that it is habitat for Sierra sweet bay (Myrica hartwegii), one of Yosemite’s rare and fragile plants.

This year, however, has been grim for the South Fork. With several exceptionally dry years in a row, the South Fork is currently extremely low. The river is fed by snow that falls and then melts off at higher elevation. This year, Yosemite got a little less than 20% of its usual snowpack, which means there wasn’t much snow to feed the park’s rivers. As of July 15, 2014, the river was flowing at a rate of 2.15 cubic feet per second (CFS), which is one of the lowest flow rates on record for this time of year. Last July, it was flowing at 9.2 CFS. At its peak, the South Fork often flows at nearly 1,000 CFS. (One cubic foot of water is equivalent to 7.48 gallons. If you have a hard time imagining a cubic foot of water, think of a basketball. One cubic foot is about the size of one basketball, so 1 CFS would be like one basketball passing by every second. Imagine 1,000 basketballs passing by every second! That’s how much water is flowing in the South Fork during its peak spring runoff.)

With so little water left in the South Fork, and with a long, dry summer ahead, Wawona’s visitors and residents alike are working hard to conserve water. No matter where you live, it’s a good idea to practice water conservation. Here are a few tips for saving water in your home:

  • Take shorter showers.
  • Catch the water you use for washing produce, and use it for watering plants.
  • Don’t let the water run while you brush your teeth.
  • Keep a pitcher of water in the refrigerator so that you don’t have to run water from the tap while it goes from warm to cold. 
  • Water your lawn in the early morning to minimize evaporation.

KL, Water-Rock-Wind, Wawona

Last updated: July 18, 2014

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