December 19th, 2008

After receiving less than 0.1” of rain during the first thirteen days of December, 0.49” of rain were recorded in Santa Rosa from Dec 14th-15th. No rain was recorded for December 16-17. A second weather system moved in on Thursday, December 18 dropping 0.17” of rain from 14:00-20:00. Rainfall began again around midnight on the 18th. Over the course of the next four hours approximately 0.23” of rain was recorded until the storm had passed through around 4AM on December 19. Runoff sampling began that morning with the first sample collected at Copeland Creek at 08:20 and the last sample collected at 16:10 at Prince Memorial Greenway.

 


Sampling Events

The following sites were sampled on this day:

  • Atascadero Creek at Bodega Hwy was a cloudy green color with no visible direction of flow.

  • Atascadero Creek at Green Valley Road also exhibited no visible flow; the water was murky green with a low dissolved oxygen content.

  • Runoff was observed in the form of cloudy water at Copeland Creek.

  • Runoff was observed in the form of cloudy water at Foss Creek.

  • The Laguna de Santa Rosa east of Sebastopol at Laguna State Park was a murky brown with no visible direction of flow, although it is a wide and deep body of water at this point. Numerous dog droppings were visible around the pathway above the Laguna.

  • The Laguna de Santa Rosa downstream of the confluence with Santa Rosa Creek (114LAGU02), called Santa Rosa Flood Canal at this location in the DeLorme Atlas-Gazeteer. The water in the Laguna was a murky brown and no flow was visible, although due to the wide and deep nature of the stream channel a small amount of flow would not be noticeable.

  • Runoff was not visible in terms of water clarity at Lower Dry Creek. Trash present.

  • Runoff was not visible in terms of water clarity at Lower Green Valley Creek.

  • Runoff was not visible in terms of water clarity at Mill Creek. However, Wallace Creek, a tributary entering Mill Creek, approximately 20 feet above the sample collection point, was a milky green color. The Mill Creek sampling location we used was the same site where previous samples have been collected by the NCRWQCB. The water at this location is too close to the confluence of the two streams to be considered well-mixed. This may explain the large difference in Total Coliform counts between the primary and duplicate samples collected at this site; 4,611 MPN & 10,462 MPN, respectively. Trash present.

  • Prince Memorial Greenway had about 10 cfs of flow. The water had a slight yellow tint with excellent clarity. It was hard to say how much runoff was present here.

  • The water was colorless at Upper Mark West. However, this stream was running at about 3-4 cfs on December 19th, 2008, but had been dry during the November 13th, 2008 scouting. The water in this stream may have consisted primarily of groundwater recharge from the December 14th-15th, 2008 rainfall. However, I suspect that some runoff from the early morning rain was still present when we sampled this site at 14:50

  • The water was colorless at Upper Santa Rosa Creek. However, the stream was running at about 3-4 cfs on December 19th, 2008 but had been dry during the November 13th, 2008 scouting. The water in this stream may have consisted primarily of groundwater recharge from the December 14th-15th, 2008 rainfall. However, I suspect that some runoff from the early morning rain was still present when we sampled this site at 15:30.