Cal-SIMETAW (California Simulation of Evapotranspiration of Applied Water)
General Description | Estimates daily soil-water balance to determine potential crop ET and applied water ET for 132 individual crops, 20 crop categories, and four non-crop land-use categories by DAU/county for use in California Water Plan. Model website at: https://water.ca.gov/Programs/Water-Use-And-Efficiency/Land-And-Water-Use/Agricultural-Water-Use-Models |
Model Domain | Water use by crops in California |
Developer | California Department of Water Resources |
Hardware computing requirements | NAN/A. Computer power is dependent on area of analysis. |
Code language | C# & and Oracle Spatial Database |
Original application | Developed from SIMETAW, constrained to CA scenario for California for 20 crops, 4 non-crop land uses use classes and historical data. Designed to estimate daily soil-water balance to determine crop evapotranspiration, (ETc (crop) and ETaw (evapotranspiration of applied water ( ETAW) for California Water Plan updates. |
Public/proprietary and cost | Public by request through DWR |
Physically or empirically based | Empirical |
Mathematical methods used |
|
Input data requirements |
|
Outputs | Format: Oracle database files. Various temporal scales (daily, monthly, yearly).
|
Pre-processing and post-processing tools | NAN/A |
Representation of uncertainty | Model verification vs. CIMIS (R = 0.98), no measure of error and several major assumptions required to run the data. No correction for runoff and runon on the sites. Assumption that rainfall cannot exceed soil water depletion. Uncertain results for longer timescales (currently run on a daily scale). |
Prevalence | Primarily used for California Water Plan updates every 5 years. ETAW and AW data is also used as inputs for irrigated agriculture models (e.g. SWAP, DAP). |
Ease of use for public entities | Requires access to additional data sources (land cover) which can add additional costs to running the model. |
Ease of obtaining information and availability of technical support | Direct contacts for developers available through DWR, technical manuals and model schematics not available online. No help desk or active working group advertised. |
Source code availability | Not immediately downloadable, but accessible through program in C# |
Status of model development | Completed and used for Water Updates every 5 years (DWR). No announcements on new directions/upgrades. |
Challenges for integration | Requires some detailed information of irrigation for crop types. Constrained number of crop typesgroups. Output can only be generated for DAUs and county level, not spatially explicit. |
References:
Medellín-Azuara, J., & Howitt, R. E. (2013). Comparing Consumptive Agricultural Water Use in the Sacramento - San Joaquin Delta. Davis, CA.
...