Evapotranspiration rates and crop coefficients for a restored marsh in the Sacramento–San Joaquin Delta, California, USA

✍ Scribed by Judy Z. Drexler; Frank E. Anderson; Richard L. Snyder

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 751 KB
• Volume: 22
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/hyp.6650

✦ Synopsis

The surface renewal method was used to estimate evapotranspiration (ET) for a restored marsh on Twitchell Island in the Sacramento-San Joaquin Delta, California, USA. ET estimates for the marsh, together with reference ET measurements from a nearby climate station, were used to determine crop coefficients over a 3-year period during the growing season. The mean ET rate for the study period was 6 mm day 1 , which is high compared with other marshes with similar vegetation. High ET rates at the marsh may be due to the windy, semi-arid Mediterranean climate of the region, and the permanently flooded nature of the marsh, which results in very low surface resistance of the vegetation. Crop coefficient (K c ) values for the marsh ranged from 0Ð73 to 1Ð18. The mean K c value over the entire study period was 0Ð95. The daily K c values for any given month varied from year to year, and the standard deviation of daily K c values varied between months. Although several climate variables were undoubtedly responsible for this variation, our analysis revealed that wind direction and the temperature of standing water in the wetland were of particular importance in determining ET rates and K c values.