Presentations 2016

Remotely Sensed Crop Mapping Applications for Water Resource Management and Decision Support

Land IQ

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Accurate and current information on constantly changing agricultural acreage and distribution of crops is critical for environmental, economic and resource management applications. Land use, resource optimization, and economic models and planning significantly depend on accurate spatial land use data, specifically crop type and change. It is important to understand the impacts of crop type and distribution, crop change, acreage, permanent crop age and associated production practices on resource issues such as water quality, water supply, groundwater depletion/recharge, and economic factors. Conversely, environmental factors, such as climate change and sensitive habitats, increasingly influence how much and where these crops are grown. For these purposes, as well as many others, a current spatial mapping base layer is integral for effective resource analysis and decision-making. Past efforts to categorize and/or spatially map land use (specifically field by field agricultural production) throughout the Central Valley of California has either been:• accurate, but intermittent and not spatially contiguous (e.g. CA Department of Water Resources crop mapping)• frequent and spatially contiguous, but with marginal accuracy (e.g. USDA Crop Data Layer)• spatially contiguous, but lacking in specific crop granularity (e.g. CA Department of Conservation Farmland Mapping)• detailed, but incomplete and not spatial (e.g. grower surveys)As a result, there is currently no highly accurate, spatially contiguous, field scale agricultural land use mapping product. In response to this need, detailed crop mapping has been completed across the state of California. Methods have been developed to accurately and efficiently map field-scale crop coverage with remotely sensing techniques. Field-scale information is important because it accurately characterizes acreage irrigated and it captures variability in crop production within parcels or operations. The result is an accurate spatial database of individual crops throughout the state of California with accuracies exceeding 95%. These data are being used to inform decisions on water resource management, support and greatly refine models, evaluate groundwater recharge suitability, and better assess the role of agriculture in management and sustainability of surface and groundwater resources. These data are also integral to the assessments that will be needed as future Groundwater Sustainability Agencies respond to the Sustainable Groundwater Management Act requirements. Growers, industry, regulators, government agencies, and commodity groups also benefit from applying spatial data for land use change, crop type, location, permanent crop age, and density for management of environmental resources and proximity to sensitive areas of water quality, air quality, disease/pest vectors, etc. Collectively, remotely sensed crop mapping data are valuable for:• Surface & groundwater modeling and assessments of groundwater pumping• Groundwater Recharge Enhancement • Evapotranspiration estimations and models (remotely sensed and conventional)• Permanent crop age determination to further refine water use assessments • Permanent (“hard” water requirements) vs. annual crops and locations• Economic & land use trend analysis• Drought and climate change impact analysis• Fallowing trends and locations• Water use efficiency & water infrastructure planning