The Sacramento-San Joaquin Delta Model#
The Sacramento-San Joaquin Delta (Delta) occurs at the confluence of the two eponymous rivers and is a crucial cornerstone of water resource management in California. While important in supporting agriculture throughout the state by conveying water to key regions, the Delta itself hosts significant production of select crops, namely alfalfa, corn, pasture, and tomatoes, among others. Challenges facing the Delta align with anticipated climate change impacts rising sea level, saline intrusion, and increasing hydrological variability. The OpenDAP model was developed as a tool to assess economic impacts of changing economic, biophysical, water management and land management conditions in the Delta. It is assumed that changes in these systemwide conditions will likely affect production decisions including total area planted and production factors use, intensity in production factors use, and choice of crops such that returns to farm and management are maximized. The OpenDAP model was embedded in a user friendly web application which runs an economic optimization model in response to user-provided scenarios of land use and water management such that crop profitability is maintained.
The OpenAg/DAP Model#
The OpenDAP Beta Version model was developed using economic and production input data for 2014, 2015, 2016, and 2017, and is calibrated based on average conditions from these four baseline years. Unit of analysis consists of Delta Islands and other agricultural clustered areas within the Legal Delta. The model is calibrated using the economic principles of Positive Mathematical Programming for disaggregate models (Howitt et al. 2012) and its architecture is based on the DAP model employed to study salinity effects in the Delta Agriculture (Medellin-Azuara et al. 2014). The calibrated model predicts decisions of farmers on cropland use and use of inputs including water within an island assuming profit maximizing behavior considering expected prices, subsidies, yields, and costs, as well as restrictions on land, water and crop specific restrictions. This is undertaken by solving the non-linear program described by equations 1 to 5 below.
Commodity Groupings#
Category |
Commodities |
|---|---|
Alfalfa |
Alfalfa and Alfalfa Mixtures | Alfalfa |
Almonds and Pistachios |
Almonds | Pistachios |
Corn |
Corn | Sorghum and Sudan | Corn | Sorghum | Sudan Grass |
Cucurbits |
Melons | Squash and Cucumbers | Cucurbit |
Deciduous |
Apples | Cherries | Miscellaneous Deciduous | Peaches/Nectarines | Pears | Plums | Prunes and Apricots | Pomegranates | Walnuts | Young Perennials | N/A Deciduous |
Dry Beans |
Beans (Dry) |
Field Crops |
Miscellaneous Field Crops | Sunflowers | Sunflower |
Grain |
Miscellaneous Grain and Hay | Wheat |
Onions and Garlic |
Onions and Garlic |
Pasture |
Miscellaneous Grasses | Mixed Pasture | Forage Grass | Pasture | Turf |
Potatoes |
Potatoes and Sweet Potatoes | Potatoes |
Processing Tomatoes |
Tomatoes |
Rice |
Rice |
Safflower |
Safflower |
Subtropical |
Citrus | Kiwis | Olives |
Vegetables |
Bush Berries | Carrots | Cole Crops | Lettuce/Leafy Greens | Miscellaneous Truck Crops | Peppers | Strawberries | Asparagus | Truck Crops |
Vineyards |
Grapes | Vineyards |
Not Included |
Fallow | Flowers | Nursery and Christmas Tree Farms | Idle | Managed Wetland | Urban | Wild Rice | Floating Vegetation | Riparian | Semi-agricultural/ROW | Upland Herbaceous | Water | Wet herbaceous/sub irrigated pasture |
Getting Access#
To get access for additional staff, please contact the WSM Lab.