Examining the Historical Discharge Record of the Salinas River
Abstract
The Salinas River, located in coastal central California, drains an area of 11,000 km2. Most of the volume of water entering the Salinas River comes from the tributaries draining the mountains to the south. This NW-SE trending coastal range receives up to 1000 mm/yr of precipitation. The Arroyo Seco (630 km2) plays a large role in delivery of this orographic precipitation to the Salinas River. The affect of local and global climate patterns on the watershed are seen in the large variability found in the discharge and precipitation. During years classified as El Ni¤o years, the Salinas watershed typically has a higher annual discharge. However, El Ni¤o years do not necessarily result in `wet' years for the basin. The increase in annual discharge from the river is predominantly due to an increase in the number of high flow days, not necessarily large flooding events. Typically rainfall events in this basin are short-lived and intense. The role of the first winter rains on the Arroyo Seco was found to be limited unless the duration is longer than 2 days. After this first event, rainfall events with intensities of > 15 mm/hour will have a large and quick affect on the river discharge, in the form of flash flooding. Hourly precipitation rates < 10 mm have little affect on the hydrograph at the mouth of the tributary due to interception of the precipitation. The quick movement of the storm hydrograph through the basin determines the delivery of sediment to the Salinas River. Looking at longer timescales, the role of the Arroyo Seco in the delivery of water and sediment to the Salinas was investigated as a means of understanding the character of the river prior to the construction of dams on the Nacimiento and San Antonio Rivers. These are the larger tributaries draining the southern mountains, but flow has been obstructed by dams since 1956. By correlating concurrent flows from the Arroyo Seco and the San Antonio and Nacimiento Rivers (above the dams), characteristics of the non-restricted tributaries were synthesized. This allowed for estimation of flows under natural rather than altered conditions for the span of the historical gaging record (1902 - 2001).
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2002
- Bibcode:
- 2002AGUFM.H21C0818F
- Keywords:
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- 1854 Precipitation (3354);
- 1860 Runoff and streamflow