Even though facilities like irrigation ponds and canals are present, they are not sufficient and the farmers depends on groundwater. Why?
Answers
Answer:
Farm ponds have great potential to improve agricultural water security through the capture, storage, and provision of water for irrigation in all regions of California. Farm ponds can also supply a water source for frost protection, recharge groundwater, and provide a wide range of additional economic and environmental benefits.
Ponds can be filled by rainfall, as is common with farm and ranch ponds that are sited at a low point and serve to collect runoff from higher in the watershed. Alternatively, farm ponds can be filled with tailwater from irrigation, which can then be recycled. Ponds can also be filled by diverting water from streams at peak winter flows, offsetting water withdrawals during the dry season when higher instream flows are needed.
Ponds can recharge groundwater, which keeps more water in the system for longer, providing greater quantities for use in the watershed and allowing seepage into streams later into the summer. Devoting more land to ponds in valleys that are overdrafting groundwater would help minimize impacts and would contribute positively to overall watershed management.
Ponds can also be used to trap, filter, and store tailwater from irrigation. Sediment can be settled and returned to the fields; water can be re-used in subsequent irrigations, reducing the need to divert or pump more irrigation water. Pumping from a pond uses much less energy than pumping groundwater. A common approach is to construct a smaller sediment trap that then flows into a pond.
Ponds are common on farms and ranches, however the vast majority of ponds are currently constructed for fish farming, fire protection, stock watering, or simply landscape beautification. Their usefulness as irrigation and watershed management tools have not been sufficiently appreciated or exploited in the West, probably because farmers have largely been able to rely on organized irrigation districts and their reservoirs to store and deliver irrigation water. As water supplies become more uncertain in California, it will behoove farmers and water regulators to make more concerted efforts to institute on-farm ponds.
Obstacles
The regulatory context for constructing new farm ponds is currently challenging. A significant obstacle to using ponds to manage watersheds is the system of water rights. As the State Water Resources Control Board attempts to permit and regulate farm ponds, they are faced with dilemmas in trying to rearrange water rights to accommodate in-stream flows and fish. The Department of Fish and Game, the Environmental Protection Agency, and county governments also have jurisdiction and their own laws and rules that govern when and how such ponds can be filled. The cost and time involved in such permitting is often discouraging to the farmer.
The cost of constructing the pond can be an issue. A tailwater return pond can easily cost $20,000-$40,000 plus $1,000 a year to maintain, although the federal government (through NRCS) will often share the construction cost, and ponds provide a long-term offset for the cost of purchased water.
Another obstacle to creating more farm ponds in intensively farmed areas is simply the opportunity cost of removing land from production. In the Central Coast, for example, where land can rent for $2,000 per acre per year, and most of the land is not owned by the people farming it, this is a barrier. The recent rise of often irrational food safety concerns in such areas as the Salinas Valley has also slowed or reversed the creation of ponds, as frogs are associated with salmonella bacteria by some in the food industry.
Ponds can attract wildlife and increase populations of endangered species such as red-legged frogs or the San Francisco garter snake. However, the National Fish and Wildlife Service has developed “safe harbor” agreements that allow the development of such ponds and limit any subsequent Endangered Species Act consequences for the farmers
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