Difference between revisions of "Carmel River Watershed: Robinson and San Clemente Creeks Flow Duration Analysis"

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Robinson Creek joins Carmel River relatively low in the watershed. It is approximately 14 km2 in area. Its aspect is to the north and lies in a narrow steep canyon. Robinson has a higher higher soil erosion index than San Clemente1. San Clemente Creek is located relatively high in the Carmel watershed, above San Clemente dam. It is approximately 40 km2 in area and has an east-northeast aspect. San Clemente has a more diverse slope content than Robinson<ref>[[Maps of the Carmel River Watershed]]</ref>. Locations of the two watersheds are in Figure 2 below.
 
Robinson Creek joins Carmel River relatively low in the watershed. It is approximately 14 km2 in area. Its aspect is to the north and lies in a narrow steep canyon. Robinson has a higher higher soil erosion index than San Clemente1. San Clemente Creek is located relatively high in the Carmel watershed, above San Clemente dam. It is approximately 40 km2 in area and has an east-northeast aspect. San Clemente has a more diverse slope content than Robinson<ref>[[Maps of the Carmel River Watershed]]</ref>. Locations of the two watersheds are in Figure 2 below.
  
[[Image:Rob.SC.map.jpg|200px]]
+
[[Image:Rob.SC.map.jpg|200px|right]]
  
 
Figure 2. Location of Robinson Creek (top highlight) and San Clemente Creek (lower highlight) within the overall Carmel River watershed.
 
Figure 2. Location of Robinson Creek (top highlight) and San Clemente Creek (lower highlight) within the overall Carmel River watershed.

Revision as of 08:55, 5 March 2009

FlowDurationCurveRCSC.png

Hydrologic setting

Robinson Creek joins Carmel River relatively low in the watershed. It is approximately 14 km2 in area. Its aspect is to the north and lies in a narrow steep canyon. Robinson has a higher higher soil erosion index than San Clemente1. San Clemente Creek is located relatively high in the Carmel watershed, above San Clemente dam. It is approximately 40 km2 in area and has an east-northeast aspect. San Clemente has a more diverse slope content than Robinson[1]. Locations of the two watersheds are in Figure 2 below.

Rob.SC.map.jpg

Figure 2. Location of Robinson Creek (top highlight) and San Clemente Creek (lower highlight) within the overall Carmel River watershed.

Analysis

Robinson Creek’s flow duration curve (FDC) indicates there is flow about 45% of the time. Overall, the smooth FDC indicates a natural, unregulated flow regime. While smooth, the FDC does curve steeper than the classic straight unregulated FDC, which may just be an indication that no specific flow lasts for a long time in the steep, narrow channel. There is a steeper part of the curve during very uncommon flows, from 4-7 m3/s, that indicate some flashy runoff response when large flow occurs. There is a slightly flat section of the curve from one to 4 m3/s, in the top 1% of flow magnitudes, indicating these size flows last for a while as the large amount of water is transported. The steep drop in the low flow section indicates the stream rapidly loses flow as the season is ending, one can infer no huge amount of baseflow entering the stream once active storms go away. San Clemente Creek’s FDC shows there is flow almost year round. The smoothness and relatively flat line shows a natural, unregulated flow regime. There are some anomalies at very high flows in the 7 to 11 m3/s area. The very flat section around 7 m3/s may indicate gage failure, estimated data, or some other unnatural phenomena. The very steep part around 10 m3/s and then flat part around 10.5 m3/s indicates unusual flow regimes. Perhaps at these flows some other flow path becomes available or there is some type of structure influencing flow like a culvert or bridge. The two curves show San Clemente Creek experiences consistently higher volume flow and maintains flow through the year much more than Robinson Creek. This makes sense as it has a larger area and lies higher in the watershed where more rainfall occurs. Overall, San Clemente Creek exhibits more of a natural unregulated FDC as seen in the flatter line. Low flows do not last long in Robinson, and they change more gradually in San Clemente indicating longer runoff/collection time or baseflow.

Summary

Comparison of the two curves show much longer flow regime at higher creek in watershed (San Clemente), and flow only half the year at Robinson. Both curves indicate some process occurring at very high (0.1% exceeded) flows. Neither stream shows strong sign of management or control structures.

References

  1. Maps of the Carmel River Watershed