The Rest of the Story on Irrigation Efficiency. Charles M. Burt, Chairman Irrigation Training and Research Center Cal Poly San Luis Obispo, CA

Transcription

1 The Rest of the Story on Irrigation Efficiency Charles M. Burt, Chairman Irrigation Training and Research Center Cal Poly San Luis Obispo, CA 1

2 The Rest of the Story on Irrigation Efficiency Dr. Charles M. Burt Irrigation Training and Research Center (ITRC) California Polytechnic State University (Cal Poly) San Luis Obispo, CA

3 How are we doing with improvement of Irrigation Efficiency? Well, we have much better hardware than before..at least for drip/micro

4 Filters 4

5 Pressure regulators 5

6 5 out of 6 PC drip emitters work great! Eurodrip PC 2 Hose with Emitters 0.5 GPH Jain Clicktif Emitter, Brown Outlet 0.5 GPH Eurodrip Corona 0.5 GPH Jain Clicktif Emitter, Black Outlet 1 GPH John Deere Supertif Brown 0.58 GPH Netafim 01WPC8 Emitter: Green, Big 2 GPH 6

7 Irrigation System Evaluations They aren t all equal. Accuracy requires VERY qualified individuals. 7

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10 Conclusion: Very good overall performance

11 Irrigation Districts are Rapidly Modernizing Example: Merced ID

12 Sprinklers Continue to Improve Slowly How to go broke in Spain 12

13 Surface Irrigation Acreage has Greatly Reduced Yes, it is possible to have efficient surface irrigation if the conditions are right. Yes, there are still significant on-farm inefficiencies. aren t easy/economical to remedy. But they

14 Are surface discharges to the San Joaquin River being reduced as requested by the Regional Board? Yes with lots of recirculation. 14

15 Farmers have minimized weed growth (no water wasted, there)

16 We ve even tried to reduce Pistachio ET

17 We tried Surround on Lerdo Road

18 There has been a great shift to crops with very efficient irrigation systems and management Figure 2. Crop type maps of North Kern Water Storage District, 1990 and (Kimmelshue and Tillman, 2014)

19 We are much better at estimating crop ET ITRC has a special METRIC process February July 19

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21 Large Field of Almonds Poor stand in a portion (Notice the lower ETc in that area)

22 Almonds Uniform stands but different percent cover Notice the lower ETc in the southern fields Still shows some variability in ETc

23 Depth, in. Depth, Non-Water Stressed 0 0 % of area receiving at least this amount Water Stressed 0 % of area receiving at least this amount 100 Stored 4.5 Stored 6 (SMD) 7.5 SMD Deep Perc 6 (SMD) 7.5 DP Under-irr 9 Approximately 55% of the crop non-uniformity is caused by irrigation system distribution uniformity

24 Great advances are being made in volumetric/flow measurement and billing. New GCID Design

25 We are doing such a great job of water conservation, that there isn t enough waste to recharge the groundwater or the rivers. Dr. Charles M. Burt Cal Poly - ITRC

26 A refresher 100% Irrigation Efficiency means that all of the irrigation water is beneficially used. Dr. Charles M. Burt Cal Poly - ITRC

27 So we are beneficially using almost all of the water. The water is being used up Dr. Charles M. Burt Cal Poly - ITRC

28 Slight problem: The water molecules go into the air as Evapotranspiration. The salt molecules stay behind in the soil, and In the groundwater Dr. Charles M. Burt Cal Poly - ITRC

29 0 Soil Depth (m) Distance (m) Almonds are damaged ITRC ECe color scale (ds/m) Cal Poly 2010 Results from ITRC study on salt accumulation typical for drip irrigated 20 yr orchard on west side SJV

30 About 50% of the salt stays behind with drip/micro. Even though there is a standard Leaching Requirement.

31 Leaching salt from under a drip line 31

32 What does this image show you about -Automating an irrigation system based on soil moisture studies? -- Measuring deep percolation? -Measuring changes in soil moisture to quantify ET? -- Soil sampling for nutrition? 0 WWhat Soil Depth (m) Distance (m) ITRC Cal Poly 2015 Results from ITRC study n salt accumulation ECe color typical scale for (ds/m) drip irrigated 20 yr orchard on west side SJV 2015

33 But let s not get buried in technical realities of automating based on soil moisture.

34 We are improving irrigation efficiencies in areas with soils that have high salinity and selenium and introduce additional salinity to rivers - Uncompahgre Valley - Grand Valley - Panoche Fan - Wellton-Mohawk 34

35 So what else is going on even though our irrigation practices are getting better and better?

36 Throughout the world, irrigation expansion has depended on groundwater overdraft Graph From NASA

37 San Joaquin Valley Groundwater Drop in 1 year Source: Calif. DWR

38 Sacramento Valley Groundwater drop in 1 year Source: California DWR

39 LAND SUBSIDENCE Source: Calif. DWR

40 Even better water and nitrogen management will be called for in the future! 40

41 We are much more efficient than 20 years ago. But we are using more water than we have. - The fish/environment? - Golf courses? - Irrigated agriculture? - Poor watershed management/chaparral? - People taking long showers?

42 The real question is: How will the shortages be allocated?

43 Allocation of shortages has just begun and it will likely be traumatic

44 Friday, January 30, Announcement on SURFACE Water Rights REPORT ON RECOMMENDED IMPROVEMENTS TO THE IMPLEMENTATION AND ENFORCEMENT OF WATER RIGHTS DURING DROUGHT CONDITIONS The State Water Resources Control Board (State Water Board or Board) is soliciting written recommendations and information on actions that should be taken to most effectively implement and enforce the water rights priority system in future dry years. Upon request, State Water Board staff is also available to meet with interested persons to discuss recommendations. State Water Board staff will use the information it receives from this solicitation and meetings with interested persons to develop a report to the State Water Board by January 31, 2015, on recommended improvements to implementation and enforcement of water rights during drought conditions.

45 The NEW challenge will be GROUNDWATER PUMPING

46 New Mexico and Arizona did NOT get it right. They restricted GROSS pumping, not CONSUMPTION

47 Facts in the San Joaquin Valley: 1. Most groundwater recharge originates as irrigation district surface water. 2. Many irrigation districts were formed, and imported water, to alleviate groundwater overdraft. 3. Many farms are outside of irrigation district boundaries, but use groundwater.

48 There isn t enough groundwater for both the irrigation districts and the farmers outside of their boundaries. Should groundwater rights (volumes) be tied to the SOURCE OF RECHARGE?

49 Thank you.