1 Turn in fire management essays (with graded outlines attached) Tuesday 4/29 Next week – (4/29) Global change – 5/1 Review for Part III unit exam (final exam) Notes 4/24

2 Today’s topic: Water in the Southwest Water stats & cycling Groundwater –Subsidence Colorado River Readings for today: Required General reading: Cadillac Desert

3 Water Information at UA Water Resources Research Center (WRRC) –Campbell, just south of 6th –Free Newsletters Arroyo Arizona Water Resource –Xeriscaping

4 96% of Earth’s water % of Earth’s fresh water is % of Earth’s fresh liquid water is Water water everywhere, not a drop to drink

5 Units: Oceans: Fresh water: surface, subsurface, or evap Water Cycle

6

7

Where do we get our Water? - – – – ( ) 8

9 What Is An Aquifer? Aquifer - - bedrock water table aquifer

10 Depth can be – Filled in with water – – Basin Fill

11

Annual Groundwater Budget Tucson Active Management Area Inflow= Outflow = Balance (OVERDRAFT) = Acre-foot: water 1 foot deep covering 1 acre (43,560 ft 2 ) = 325,851 gal. SRC Pool: ~2 acre-feet

13 Consequences Of Overdraft

14 From over pumping of groundwater Over 15 feet in ~40 years Everything sinks (even trees) Can be general, or with fissures. Subsidence

15 Subsidence Fissuring and Infrastructure -

16 Extent of Subsidence Areas with 1600 ft. of sediments (gray) Areas with serious subsidence (red) –Agriculture areas –Municipalities Conclusion: Best not to deplete groundwater

17

18 How Much Water Left Under Tucson? So, left,

19 Well Hydrograph Pima & Swan

20 Consequences Of Overdraft

21 Colorado River Watershed Seems big, but actually not (m 3 /sec): –Colorado: --- –Columbia: (40x) –Miss.: (104x) –Amazon: (1000x) Surface Water Source:

22 Lee’s Ferry flow: 13.5 maf/yr How many people would that provide for?

23 Whither the Rainfall? Assume avg ppt of 12 in./yr Assume half of CRB above Lee’s ferry CRB receives over 5x more rainfall than it drains Where does 80% of rainfall go?

24 Colorado River Compact, 1922 AZ: W.S. Norviel (2 nd from left) 4 th from left? (hint: It’s not Haury)

25 WY, CO, UT, NM – Upper Basin AZ, NV, CA – Lower Basin –AZ: of basin, of water –Who was left out? 7.5 maf for each basin per year –75 maf to Lower Basin per decade Extra 1 maf for Lower Basin, just to be nice. Colorado River Compact

26 Flow was assumed to 16.4 maf per year Past 300 years: –Average: –Range: How do we know this? Reality Check

27 Navajo Tribe –All within basin –Might claim > 5 maf –Can’t use it, but might sell it Mexico –1944 treaty: 1.5 maf –No flow to delta: water, silt, nutrients Other Parties

28 Colorado River to Tucson? Carl Hayden legacy Begun in 1960s 300+ miles of canals Uphill –Havasu: 482 ft. –Enormous pumps Magnificent project $3.6 billion

29 CAP Pump: – gal./sec. – up Hohokam would be so proud!!

–CAP water unpopular to drink “ –CAP expensive to farm Only 1 profitable crop? –Maybe 2?? Arizona and CAP Water

31 Importing Salts to Southern Arizona CAP water has 580 mg/L salts Where goeth the salts?

32 Groundwater Pumping

33 Fix your faucets all you want … People replace cotton and lettuce, water use  Statewide Use: It’s agriculture

34 Water Summary – SW big rivers –