SSJ Delta Input Data and Processing

Summary of Data

The Open Delta Agricultural Production Model employs data on land use, cost of production, price, yield and applied water to estimate profit-maximizing patterns of Delta crops under varying conditions (Medellin-Azuara et al., 2018). Data for these inputs are available in tabular and shapefile formats from various state and federal agencies and University of California crop Cost and Return studies. The model uses GIS crop acreage shapefiles to generate a tabular dataset of 2014-2017 crop acreages in defined Delta regions. Analysis of raw model input data yields results which may indicate needs for additional quality control. For example, some widely planted commodities such as corn, alfalfa, and pasture crops may produce borderline or negative net returns on farming, whereas some vegetable crops such as cucurbits (gourds) and potatoes show higher marginal profits, yet these represent a relatively small proportion of the total irrigated area in the Delta. These wide ranges in expected returns may be explained by factors not captured by model, such as market behavior or impacts of resolving commodity level data to crop groups. The model is best served for determining economically optimal solutions to cropping distributions, while utilizing observed patterns as a constraint on adaptation to prevent overspecialization. Model outputs include land allocation, water use, net revenues and estimated agricultural land value.

Results show that corn, pasture and alfalfa are the top crop commodities grown in the Delta by irrigated area. Yet these top crops (corn, alfalfa and pasture) make up a relatively small portion of overall value despite dominating the available cropping area. Additionally, these crops consume over 50% of the agricultural water used in the Delta while high value crops yield high returns with a much lower water footprint. Vineyards and tomatoes provide the highest gross revenues, combining to constitute roughly 30-40% of overall value.

Summary of Inputs

The following table summarizes data sources used for defining model inputs for the Washington State model area.

Data	Spatial Resolution	Temporal Resolution	Source
Land use	Field	Annual (limited)	LandIQ and DWR View all years, Statewide downloads 2014 and 2016
Crop water demand	Detailed Analysis Unit (DAU)	Annual	DWR Land & Water Use Estimates
Crop price	County	Annual	USDA National Agricultural Statistics Service (NASS) and CDFA Agricultural Statistics Review
Crop yield	County	Annual	USDA National Agricultural Statistics Service (NASS) and CDFA Agricultural Statistics Review
Crop production costs	County/macro-region	Sparse	UC Davis Cooperative Extension Cost and Return Studies
Supply elasticities		Annual	County Ag Commissioner Reports

Land Use and Crop Groups

Whereas Delta agriculture contains many commodities, modeling crops individually can pose many challenges in data availability and overall performance when evaluating cropping patterns. Especially for crops which are grown in low amounts (small acreage crops), data for prices, yields, production costs and water requirements are often not available. Information for crop water requirements are derived from crop-specific evapotranspiration coefficients which are rarely calculated for uncommon commodities, while data for prices and yields from NASS are reported only for crops with enough production to verify reliability. To reduce the scale of the model and circumnavigate these issues, OpenDAP utilizes a set of 20 crop categories employed by the Department of Water Resources (DWR) in water efficiency and planning documents and datasets. Crops are grouped based on several factors – these include crop biophysics (water requirements, family of crop, etc.), harvest characteristics (how harvest occurs, seasonality considerations, etc.) and most importantly, expected marginal returns (price multiplied by yield).

After grouping crops by category, each category is assigned a proxy commodity which represents the production economics of the crop group. The same proxy is used for price and yield information as well as for production costs. Applied water requirements are reported by DWR at the same category grouping level. The table below summarizes all categories employed along with the included commodities and proxies. For most cases, the assigned proxy represents well the overall economics of the crop group because many of the groups are almost exclusively dominated by a single commodity within the Delta. For example, the “Corn” group contains only a single commodity, and while the “Almonds” group contains also pistachios, pistachios have very few acres grown in the Delta. The most complex groups are “Orchards” and “Vegetables”, each of which contain many commodities and are not overly dominated by a single crop by acreage. In these cases, typically the most dominant crop by acreage is used as a proxy, with the expectation that considerations taken in grouping reduce the variance in production costs and marginal returns between commodities within groups. Use of proxies in these complex categories can lead to over- or under-estimation of total value of crop agriculture in the Delta from all commodities, which should be considered when analyzing economic results from the model. While modeling all commodities individually would theoretically provide the most accurate representation of the system, this poses challenges in data availability and model scale along with introducing new solver infeasibilities where crop groups are too small to effectively allocate land between.

OpenAg Crop	Commodities Included	Proxy Crop
Alfalfa	Alfalfa	Alfalfa hay
Almonds & Pistachios	Almond | Pistachio	Almond
Corn	Corn	Field Corn
Cotton	Cotton	Cotton
Cucurbits	Cucumber | Eggplant | Squash | Gourd | Zucchini | Pumpkin | Melon (various)	Watermelon
Dry Beans	Garbanzo Bean | Fava Bean | Pea | Bean (dried)	Dry Bean
Fresh Tomatoes	Tomato (fresh)	Fresh Tomato
Grain	Barley | Oat | Triticale | Wheat	Wheat
Onions & Garlic	Garlic | Onion	Onion
Deciduous	Apple | Apricot | Pear | Cashew | Cherry | Jujube | Nectarine | Peach | Pecan | Persimmon | Plum | Pomegranate | Pomelo | Prune | Quince | Walnut | Stonefruit (various)	Walnut
Field Crops	Oilseed | Sorghum | Sudangrass | Sugarcane | Sunflower	Grain silage
Vegetables	Arugula | Artichoke | Asparagus | Basil | Blackberry | Blueberry | Bok Choy | Boysenberry | Broccoli | Brussel Sprout | Berry (other) | Cabbage | Cactus | Carrot | Cauliflower | Celery | Chestnut | Chive | Cilantro | Collard | Daikon | Dill | Fennel | Herb (other) | Kale | Leek | Lettuce | Mustard | Okra | Parsley | Parsnip | Pepper | Radish | Rutabaga | Spinach | Strawberry | Turnip | Vegetable (other) | Yam	Asparagus
Pasture	Pasture (mixed) | pastureland | rangeland | rye	Pasture
Potatoes	Potato | Sweet Potato	Potato
Processing Tomatoes	Tomato (processing)	Processing Tomato
Rice	Rice	Rice
Safflower	Safflower	Safflower
Sugar Beets	Sugarbeet	Sugar beet
Subtropical	Avocado | Citrus (other) | Fig | Grapefruit | Kiwi | Kumquat | Lemon | Olive | Orange | Papaya | Tangelo | Tangerine	Olive
Vineyards	Grape (various)	Wine Grapes

Region Boundaries and Land Use

Adaptation of Delta Region Boundary Layers

The original Delta island boundaries shapefile provided by the Delta Stewardship Council contained some empty space within the DWR Legal Delta Boundary, in which sections of the Delta not considered “islands” were not covered by polygons. To ensure inclusion of these areas in the agricultural model, polygons are created in each of the blank spaces and aggregated into three separate polygons for southern, middle and northern regions.

Intersecting Delta Regions with Cropped Polygons

The land use shapefiles for each year (sourced from DWR/Land IQ) are clipped to fit within the DWR Legal Delta Boundary. The resulting layer subset is then intersected with the Delta Island Boundaries layer to yield the observed cropping pattern by island. In order to process the data, the area was then calculated via the geoprocessing tool to calculate geometry for each individual polygon. The final shapefile for each year is then exported from a GIS program to a comma separated value (.csv) file for postprocessing.

Land Use

Land use data is obtained by bridging commodities to crop groups and assigning each region in the study area a unique Delta region code. The “ACRES” attribute in the employed Land IQ dataset is then cross-referenced with the calculated area of each polygon to ensure acreage data is not over-projected; if the calculated polygon area is less than the attribute area, then the polygon area is used to prevent discrepancies in the physical land available for farming. Final acres by crop group are aggregated for each region and exported for use as model inputs. When assigning crop groups, care was taken to ensure that crops with prominent acreages and/or revenue were separated into their own respective groups. Turf, eucalyptus and nursery trees were excluded from the totals as they are not considered traditional agricultural products and prove challenging to accurately model (see section 3.3). Double cropping was included in total acreage and revenue, consisting primarily of small grains grown on fields that are typically fallowed.

Costs of Production

Production costs are broken into five major cost categories: land rental, labor, supplies, establishment (if applicable), and water. Proxy crops are assigned to each crop group and costs are obtained from UC Davis Cost and Return studies pertinent to that proxy group (see Table A3 of the appendix). Costs are inflated or deflated from the study year to 2015 dollars using Equation (1):

(1)\[C_{2015} = C_n(1-I_n)\]

where \(C_{2015}\) is the cost in 2015 dollars, \(C_n\) is the nominal cost in the study year, n, and \(I_n\) is the cumulative inflation rate between year n and 2015.

Costs in the current model version draw information from several studies and employ an average cost for each major cost type based on the post-inflation value across all studies utilized (see Table A3 of the appendix for a full list of all studies by crop group). Water is assumed to cost $10/AF as a baseline. Current cost assessments do not include annualized establishment costs; however, data is available to include this category in future economic modeling that considers annualized capital costs.

Crop Prices and Yields

Price and yield information for the selection of crops in the model are obtained by bridging commodities to crop groups and bridging from island to county. County level data for price and yield by year from the National Agricultural Statistics Service (NASS) is then assigned to each crop by island based on the bridging procedures. In cases where county-specific data was unavailable for the proxy crop, an average value for other counties intersecting the study region was substituted. For complex crop groups such as deciduous fruits and truck crops, a proxy crop is chosen to represent the group (see Table A2 of the Appendix). Prices are shown in 2015 dollars following methods analogous to those used for costs ((1)).

For crop categories for which the sum of all costs exceeds the gross crop revenues, price is assumed to have an implicit subsidy such that net returns are roughly 5 percent above the total costs. While negative net returns are sometimes a reality for farmers, it is assumed that in the average most farms operate within the aforesaid profit margin. The adjustment is shown in (2) below:

(2)\[p = 1.05(\frac{\omega_{land} + \omega_{supply} + x_{water}\omega_{water}}{y})\]

where \(\omega\) refers to the cost associated with each input ($/ac), \(x_{water}\) is the applied water requirement per acre of land (AF/ac) and y is the yield (ton/ac). This correction allows for a 5% profit margin in final production calculations, yet it can be adjusted or eliminated or updated as better production cost information becomes available. Prices and derivative values (such as gross returns and profits) represented here reflect base values prior to corrections to the subset of crops.

Applied Water

Applied water data is provided at the detailed analysis unit and county level (DAU-Co) and is aggregated to individual island regions by applying a weighted average using Equations (3) and (4) below:

(3)\[AW_{ik} = \frac{\sum_{w=1}^{n}l_{iw}AW_{iw}}{\sum_{w=1}^{n}l_{iw}}\]

(4)\[AW_{ij} = \sum_{k=1}^{n}f_{jk}AW_{ik}\]

where \(i\) is the crop index, \(k\) is the DAU index, \(w\) is the county index for each DAU, \(j\) is the district index, \(l\) is irrigated acreage and \(f\) represents the vector of area fractions of DAU’s for a given island. Prior to integrating data at the island level, missing data for individual DAU’s by crop group are patched with the average applied water value for all other DAU’s across the study area. Applied water data for 2015 is used for all model years (2014-2017) due to a relatively low inter-annual variability across the study region.

Additional Tables

Region names and associated IDs

Region Name	ID	County
Atlas Tract	DAP001	San Joaquin
Bacon Island	DAP002	San Joaquin
Bethel Island	DAP003	Contra Costa
Big Break	DAP004	Contra Costa
Bishop Tract/Dlis-14	DAP005	San Joaquin
Bixler Tract	DAP006	Contra Costa
Bouldin Island	DAP007	San Joaquin
Brack Tract	DAP008	San Joaquin
Bradford Island	DAP009	Contra Costa
Brannan-Andrus	DAP010	Sacramento
Browns Island	DAP011	Contra Costa
Byron Tract	DAP012	Contra Costa
Cache Haas Area	DAP013	Solano
Canal Ranch Tract	DAP014	San Joaquin
Central Stockton	DAP015	San Joaquin
Chipps Island South	DAP016	Solano
Clifton Court Forebay	DAP017	Contra Costa
Coney Island	DAP018	Contra Costa
Dead Horse Island	DAP019	Sacramento
Decker Island	DAP020	Solano
Dlis-01 (Pittsburg Area)	DAP021	Contra Costa
Dlis-02 (Antioch Area)	DAP022	Contra Costa
Dlis-03 (Lower Sherman Island)	DAP023	Sacramento
Dlis-04 (West Island)	DAP024	Sacramento
Dlis-05 (Donlon Island)	DAP025	Sacramento
Dlis-06 (Oakley Area)	DAP026	Contra Costa
Dlis-07 (Knightsen Area)	DAP027	Contra Costa
Dlis-08 (Discovery Bay Area)	DAP028	Contra Costa
Dlis-09 (Byron Area)	DAP029	Contra Costa
Dlis-10	DAP030	Contra Costa
Dlis-12 (Paradise Cut)	DAP031	San Joaquin
Dlis-15	DAP032	San Joaquin
Dlis-16 (Lodi)	DAP033	San Joaquin
Dlis-17	DAP034	San Joaquin
Dlis-18	DAP035	San Joaquin
Dlis-19 (Grizzly Slough Area)	DAP036	Sacramento
Dlis-20 (Yolo Bypass)	DAP037	Yolo
Dlis-21	DAP038	Solano
Dlis-22 (Rio Vista)	DAP039	Solano
Dlis-23 (Georgiana Oxbow)	DAP040	Sacramento
Dlis-62	DAP042	Solano
Dlis-63 (Grizzly Island Area)	DAP043	Solano
Dlis-64	DAP044	Contra Costa
Drexler Pocket	DAP045	San Joaquin
Drexler Tract	DAP046	San Joaquin
Dutch Slough	DAP047	Contra Costa
Egbert Tract	DAP048	Solano
Ehrheardt Club	DAP049	Sacramento
Empire Tract	DAP050	San Joaquin
Fabian Tract	DAP051	San Joaquin
Fay Island	DAP052	San Joaquin
Franks Tract	DAP053	Contra Costa
Glanville	DAP054	Sacramento
Glide District	DAP055	Yolo
Grand Island	DAP056	Sacramento
Hastings Tract	DAP057	Solano
Holland Tract	DAP058	Contra Costa
Holt Station	DAP059	San Joaquin
Honker Lake Tract	DAP060	San Joaquin
Hotchkiss Tract	DAP061	Contra Costa
Ida Island	DAP062	Sacramento
Jersey Island	DAP063	Contra Costa
Jones Tract (Lower And Upper)	DAP064	San Joaquin
Kasson District	DAP065	San Joaquin
King Island	DAP066	San Joaquin
Kings Island	DAP067	San Joaquin
Libby Mcneil	DAP068	Sacramento
Liberty Island	DAP069	Solano
Lisbon District	DAP070	Yolo
Little Egbert Tract	DAP071	Solano
Little Franks Tract	DAP072	Contra Costa
Little Mandeville Island	DAP073	San Joaquin
Long Island	DAP074	Sacramento
Lower Roberts Island	DAP075	San Joaquin
Maintenance Area 9 North	DAP076	Sacramento
Maintenance Area 9 South	DAP077	Sacramento
Mandeville Island	DAP078	San Joaquin
Mccormack-Williamson Tract	DAP079	Sacramento
Mcdonald Island	DAP080	San Joaquin
Mcmullin Ranch	DAP081	San Joaquin
Medford Island	DAP082	San Joaquin
Merritt Island	DAP083	Yolo
Middle & Upper Roberts Island	DAP084	San Joaquin
Middle Delta Extra	DAP085	Contra Costa
Mildred Island	DAP086	San Joaquin
Mossdale Island	DAP087	San Joaquin
Netherlands	DAP088	Yolo
New Hope Tract	DAP089	San Joaquin
North Delta Extra	DAP090	Solano
North Stockton	DAP091	San Joaquin
Palm-Orwood	DAP092	Contra Costa
Paradise Junction	DAP093	San Joaquin
Pearson District	DAP094	Sacramento
Pescadero District	DAP095	San Joaquin
Peters Pocket	DAP096	Solano
Pico-Naglee	DAP097	San Joaquin
Prospect Island	DAP098	Solano
Quimby Island	DAP099	Contra Costa
Randall Island	DAP100	Sacramento
Reclamation District 17	DAP101	San Joaquin
Rindge Tract	DAP102	San Joaquin
Rio Blanco Tract	DAP103	San Joaquin
River Junction	DAP104	San Joaquin
Rough And Ready Island	DAP105	San Joaquin
Ryer Island	DAP106	Solano
Sherman Island	DAP107	Sacramento
Shima Tract	DAP108	San Joaquin
Shin Kee Tract	DAP109	San Joaquin
South Delta Extra	DAP110	San Joaquin
Stark Tract	DAP111	San Joaquin
Staten Island	DAP112	San Joaquin
Stewart Tract	DAP113	San Joaquin
Sutter Island	DAP114	Sacramento
Terminous Tract	DAP115	San Joaquin
Twitchell Island	DAP116	Sacramento
Tyler Island	DAP117	Sacramento
Union Island East	DAP118	San Joaquin
Union Island West	DAP119	San Joaquin
Upper Andrus Island	DAP120	Sacramento
Veale Tract	DAP121	Contra Costa
Venice Island	DAP122	San Joaquin
Victoria Island	DAP123	San Joaquin
Walnut Grove	DAP124	Sacramento
Walthall	DAP125	San Joaquin
Webb Tract	DAP126	Contra Costa
West Sacramento	DAP127	Yolo
Wetherbee Lake	DAP128	San Joaquin
Winter Island	DAP129	Contra Costa
Woodward Island	DAP130	San Joaquin
Wright-Elmwood Tract	DAP131	San Joaquin
Yolano	DAP132	Solano

UC Davis cost and return studies utilized in characterizing costs of production

Crop Group	Study Commodity	Study Year	Study Region	Study Link
Alfalfa	Alfalfa hay	2014	Sacramento Valley	link
Alfalfa	Alfalfa hay	2015	Sacramento Valley	link
Alfalfa	Alfalfa hay	2008	Sacramento Valley	link
Almonds	Almond	2016	Sacramento Valley	link
Almonds	Almond	2019	Sacramento Valley	link
Almonds	Almond	2012	Sacramento Valley	link
Corn	Field corn	2008	Sacramento Valley	link
Corn	Field corn	2015	North/South San Joaquin Valley	link
Cotton	Cotton	2012	North/South San Joaquin Valley	link
Cucurbits	Watermelon	2003	Imperial County	link
Cucurbits	Watermelon	2000	Imperial County	link
Dry Beans	Dry bean	2014	Sacramento Valley	link
Dry Beans	Dry bean	2014	Sacramento Valley	link
Fresh Tomato	Fresh tomato	2007	North/South San Joaquin Valley	link
Grain	Wheat	2016	Sacramento Valley	link
Grain	Wheat	2009	Sacramento Valley	link
Onions	Onion	2006	South San Joaquin Valley	link
Orchards	Walnut	2018	Sacramento Valley	link
Orchards	Walnut	2015	Sacramento Valley	link
Orchards	Bartlett pear	2010	Sacramento Valley	link
Field	Grain silage	2013	South San Joaquin Valley	link
Vegetables	Asparagus	2013	North San Joaquin Valley	link
Pasture	Pasture	2015	Sacramento Valley	link
Pasture	Pasture	2015	Sacramento Valley	link
Pasture	Pasture	2003	Sacramento Valley	link
Potato	Potato	2015	Klamath Basin	link
Potato	Potato	2008	Klamath Basin	link
Processing Tomatoes	Processing tomato	2017	Sacramento Valley	link
Processing Tomatoes	Processing tomato	2014	Sacramento Valley	link
Processing Tomatoes	Processing tomato	2014	Sacramento Valley	link
Rice	Rice	2015	Sacramento Valley	link
Safflower	Safflower	2011	Sacramento Valley	link
Sugar Beets	Sugar beet	2003	Southeast Interior	link
Subtropical	Olive	2016	Sacramento Valley	link
Subtropical	Olive	2011	Sacramento Valley	link
Vineyards	Wine grape	2013	Sacramento Valley	link
Vineyards	Wine grape	2008	Sacramento Valley	link
Vineyards	Wine grape	2016	North San Joaquin Valley	link