MONITORING THE EFFECTS OF CLIMATE CHANGE ON SPRINGS, SEEPS AND OTHER WATER RESOURCES IN THE MOJAVE NATIONAL PRESERVE Boris Poff and Debra Hughson Mojave National Preserve, California
CLIMATE CHANGE Predictions of anthropogenic climate change are based on General Circulation Models (GCM). GCMs (later called Global Change Models) Incorporate processes such as the carbon cycle and ocean chemistry Solve primitive fluid transport equations subject to solar radiation and rotation of the earth by finite difference, finite element, or spectral methods. The Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report included results from 22 different GCMs.
CLIMATE CHANGE
CLIMATE CHANGE Modeled changes in annual mean precipitation minus evaporation over the American Southwest (125{degrees}W to 95{degrees}W and 25{degrees}N to 40{degrees}N, land areas only), averaged over ensemble members for each of the 19 models, from R. Seager et al., Science 316, 1181-1184 (2007)
CLIMATE CHANGE Results of 15 GCMs from the IPCC Fourth Assessment Report show areas of the southwestern United States and northern Mexico as the most persistent hotspots for climate change. Responsiveness of the southwestern hotspot comes from increased variability in precipitation it ti from one year to the next. (not from progressive warming or a long-term rise or fall in precipitation) Diffenbaugh, N. S., F. Giorgi, and J. S. Pal (2008), Climate change hotspots in the United States, Geophys. Res. Lett., 35, Richard A. Kerr Science 15 August 2008 321: 909 (in News Focus)
MOJAVE NATIONAL PRESERVE LOCATION
PRECIPITATION PAST
PRECIPITATION FUTURE Global Climate Models generally agree Drying trend in the desert southwest is already under way Will continue through the 21st century Drought duration is predicted to increase Intensity of droughts is predicted to increase Proportion of precipitation that comes from extreme events is predicted to increase What is now considered a drought is likely to become the new normal An increase in extreme weather patterns will exacerbate fire conditions and stress ecosystems
DESERTS CAN BURN
HACKBERRY FIRE 2005 Mon nthly Total Pr recip (inches ) 5 4.5 4 3.5 3 2.5 2 1.5 1 0.5 0 2004-2005 Average Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Record winter precipitation 2004 2005 followed by 2 dry summer months resulted in abundant fuel. Lightening strikes ignited the Hackberry Complex Fire June 22, 2005 that burned 70,736 acres of the Mojave National Preserve.
WATER RESOURCES SEEPS & SPRINGS
WATER RESOURCES PERCHED AQUIFERS
SAGAMORE MINE
MAIL SPRING
WATER RESOURCES - FACTS Currently 250 recorded spring & seep locations in Mojave National Preserve (includes spring complexes) About half of these are developed (118) All but 2 or 3 are mountain-front type springs discharging from perched aquifers Unlikely l to be affected by groundwater pumping from local basin aquifers Sensitive to variable precipitation p and like to go dry in a multiyear drought Springs and seeps are the only natural water sources in a 1.6 million acre park for 321 bird and 50 mammal species
SPRING ASSESSMENT Collecting Baseline Data Discharge (if any) Dissolved O 2 ph Salinity Conductivity GPS Photo Points Flora (exotics) Fauna
DEVELOPED SPRINGS & SEEPS dams, 6 excavation, 5 gauging station, 1 wells, 17 drinkers, 33 diversions, 29 qanats, 27
HENRY SPRING
CASTLE PEAK SPRING
GOLDSTONE CANYON
PIUTE SPRING Faulting and erosion cause discharge from the east side of the local Lanfair Valley aquifer at Piute Spring that creates a narrow riparian corridor a couple kilometers in length. Recharge to the aquifer comes from precipitation in the New York Mountains and Castle Peak.
MC SPRINGS The Mojave river flows north from the San Bernardino Mountains to the closed basin of Soda Lake playa. At the edge of the playa are several seeps and small springs, the largest of which is the last refuge for the endangered Mohave tui chub. These springs are fed by seepage from a local limestone aquifer to the west.
MORNING STAR MINE
WILDLIFE IN THE MOJAVE DESERT
WILDLIFE IN THE MOJAVE DESERT
SPRING SURVEYS Mid-September to mid-november Least available surface water Started in 2004 Mostly volunteers Wet Hand test
WET AND DRY SPRINGS & SEEPS 2005 2006
WET AND DRY SPRINGS & SEEPS 2007 2008
SPRING SURVEYS RESULTS 250 Not Surveyed Dry 200 Wet 150 100 50 0 2004 2005 2006 2007 2008
ADDITIONAL INFORMATION GATHERED 60 50 60 Flowing Tamarisk Burros 40 30 20 35 35 10 4 5 16 3 14 12 0 2006 2007 2008
PRECIPITATION & WET SPRINGS/SEEPS Precipitation (inches) Percentage wet springs 30 90.0 25 20 15 10 5 0 2004 2005 2006 2007 2008 85.0 80.0 75.0 70.0 65.0 60.0 55.0 50.0
CONCLUSION Based on this small sample, springs and seeps in Mojave National Preserve appear to respond rapidly to annual rainfall and generally have aquifer storage capacity to persist through about two dry years. Future looks dry for springs and seeps in the Mojave National Preserve Unreliability of natural water resources will make it harder for wildlife species to hang on (already fringe habitat for some species) Poses challenges for park management
QUESTIONS???