AGST 3000 Agriculture, Society and the Natural World

1. Water andIrrigationRead “From Farms to Floodplains & Filtration Systems”…in class writing assignmentRead “Irrigation Drainwater Contamination in the San Joaquin Valley”…Journal Writing Assignment AGST 3000 Agriculture, Society and the Natural World

2. Irrigation "Whiskey's for drinking; water's for fighting over" – Cities, farmers and environmentalists have battled over who will control California's water forever Why? Our Valley Climate! • Irrigated surface water scarce in spite of flooding • Extended summer drought • Southern and western portions quite dry

3. Groundwater supply initially huge • Maybe as much as 750,000,000 acre feet accumulated over thousands of years • Efficient pumps developed around 1920 • Irrigated acreage rapidly expanded several fold • Groundwater levels began to drop rapidly

4. IRRIGATION A. Definition: Supplying water to plants in an artificial manner. (39% of all freshwater in the US is used to irrigate crops) 1. Ancient practice – first irrigation used ditches to divert rivers and streams. 2. California agriculture relies on irrigation. a. Mediterranean climate b. Crop diversification c. Economics

5. Population Water Needs According to U.S. Census Bureau figures, California’s population currently is over 36 million, and is projected to hit 49.3 million by 2025. 1998 California Water Plan update: the state Department of Water Resources (DWR) forecast a gap between water supply and demand ranging from 2.4 million acre-feet during normal years up to 6.2 million acre-feet in drought years by 2020.

6. An acre-foot = An acre-foot of water is about 326,000 gallons – enough to cover an acre of land, about the size of a football field, 1 foot deep and meet the average needs of between one and two residential households

7. Sources of Water • Rain and Snow replenishes the surface water and underground aquifers • Ground Water (aquifers) • Surface Water (rivers, lakes, reservoirs) • Water Cycle Handout

8. Sources of Surface Water California, there are two major arteries serving as the sources of surface water for urban and agricultural areas: • The Sacramento-San Joaquin Delta (Bay-Delta) and • The Colorado River

9. Major Rivers

10. The Delta • Delta serves as a major water source for approximately two-thirds of the state – over 22 million people • The region is fed by two major rivers: the Sacramento from the north and the San Joaquin from the south

11. The Delta • Mixture of fresh water from these two waterways and numerous tributaries combine with salty ocean water from San Francisco Bay to create the largest estuary on the West Coast of North America - The San Joaquin Delta. • Massive pumps at the southern end of this marsh pull approximately 5.5 million acre-feet annually of fresh water southward to Central Valley farmland via the Central Valley Project and ultimately, to the southern California region via the State Water Project.

12. State Projects

13. Federal Central Valley Project • FDR and U.S. Reclamation Service looking for projects, took over CVP in 1935, began construction in 1937 • Eventually completed in 1950’s • Final cost more than $500 million • Distributes more than 3,000,000 acre feet of water • Almost all used for agriculture • No connections to Southern California initially

14. Federal Projects

15. Local Projects

16. All Projects and Rivers

17. The Colorado River • Colorado River winds its way through the southwestern United States before terminating in the Gulf of California in Mexico. • Provides water to seven states including California, with each state's water use determined by the Colorado River Compact of 1922. • California permitted to use 4.4 million acre-feet annually. • For over a decade, California has been using well beyond the 1922 allotment. • As water conditions have tightened in several of the other states, the secretary of the Interior has demanded that California reduce its use of the Colorado River - a major challenge to river water users.

18. Basic Types of Irrigation Flood – Explain used in almonds, peaches, walnuts, rice, alfalfa

19. Flood in the West, Border in the East

20. Flood Irrigation continued… Advantages: • inexpensive • less labor • large amounts of water leach salts • rodent control

21. Flood Irrigation continued… Disadvantages: • land must be leveled or contoured • uses large amounts of water • water loss through evaporation • may cause disease in some crops if applied incorrectly • run off water can cause problems (silt buildup in rivers, may contain pesticides)

22. Furrow Irrigation Used in row crops such as beans, tomatoes, corn, sugar beets other vegetable crops. Similar advantages and disadvantages to flood irrigation.

23. Furrow Irrigation

24. Sprinkler Irrigation Many types micro-sprinklers, solid set, aluminum pipe a. Advantages: use less water, more precise amounts of water can be applied, less run off (tail water), may be used on slightly hilly land b. Disadvantages: expensive (installation, labor, filters, maintenance), salt buildup

26. Better spray version of center pivot for water conservaton

27. Drip Irrigation Used on specific crops, such as grapes, trees (such as almonds, cherries, peaches) a. Advantages: • uses less water • very precise amounts as well as fertilizer b. Disadvantages: • expensive to install, (labor, equipment, maintenance)

28. Drip Irrigation

29. Subsurface Irrigation

30. Questions on Irrigation: 1. Where does irrigation water come from? a. Wells – underground aquifers b. River – “Riparian rights” or water rights c. Irrigation Districts – provide water from large water sources, lakes, reservoirs (dams)

31. What are concerns people have over the use of irrigation in agriculture? a. Overdraft of underground water supplies (aquifers). b. Water pollution – silt, herbicides, pesticides added to irrigation water runs off into lakes, rivers, etc. c. Concerns over water waste – flood irrigation uses a lot of water d. Production of crops in California that are not water efficient – alfalfa and cotton.

32. How has agriculture addressed the public’s concerns over water usage? a. The #1 water user in California is ___________________________. (set the record straight) *California and Texas are the only 2 states that do not have regulations on groundwater pumping.

34. Water Problems Erosion Pollution Waste

35. Erosion • Power of a droplet of water striking the soil surface • Moves tons of soil • Runs off to rivers and streams (siltation) • Tons of soil lost

36. Pollution What types of water pollution? • Underground water supplies… • Surface runoff (erosion and contamination from crop and animal activities) • Soil water (salts) • Pre-ag existance • Ag production induced

37. Water Pollution Mitigation • A couple of Answers • Total containment of runoff or drainage from intensive animal facilities…lagoons • soil polymers – adhere to water particles preventing their runoff • use of IPM and GMO’s (reduce the need for chemicals)

38. Water Waste Caused by evaporation, infiltration, runoff Flood irrigation is the largest waste of water Drip and micro sprinkler use Cost/economics – as the price of water increases, farmers can afford to use less and must become more efficient.

39. Economics Driven Politics For specific types of Agriculture production… Special Treatment, Government Subsidies and Corporate Welfare • Water Projects • Non-point source pollution in the past • Subsidies from government that encourage production of high water use commodities (Cotton and Milk)