Climate, Drought, and Wildfire Effects on Water Quality

1. Climate, Drought, and Wildfire Effects on Water Quality

2. Recent Conditions and Short-Term Forecast http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/01_temp_cond.html

3. http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/02_prec_cond.htmlhttp://www.ispe.arizona.edu/climas/forecasts/oct2005figs/02_prec_cond.html

4. http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/03_drought_monitor.htmlhttp://www.ispe.arizona.edu/climas/forecasts/oct2005figs/03_drought_monitor.html

5. http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/05_az_resvr.htmlhttp://www.ispe.arizona.edu/climas/forecasts/oct2005figs/05_az_resvr.html

6. http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/08_temp_outlook.htmlhttp://www.ispe.arizona.edu/climas/forecasts/oct2005figs/08_temp_outlook.html

7. http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/9_prec_outlook.htmlhttp://www.ispe.arizona.edu/climas/forecasts/oct2005figs/9_prec_outlook.html

8. http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/12_enso_outlook.htmlhttp://www.ispe.arizona.edu/climas/forecasts/oct2005figs/12_enso_outlook.html

9. http://www.ispe.arizona.edu/climas/forecasts/oct2005figs/12_enso_outlook.htmlhttp://www.ispe.arizona.edu/climas/forecasts/oct2005figs/12_enso_outlook.html

10. Historical Drought in the Southwest • Palmer Drought Severity index • Soil moisture availability • Incorporates • Precipitation, most important • Temperature • Soil conditions • Includes time lags • If it’s been dry for months, a single rainstorm will not change drought to wet • Negative PDSI = dry, positive PDSI = wet

12. Pacific Decadal Oscillation • Regular pattern of high and low pressure systems over the northern portions of the Pacific Ocean. • 20- to 30-year time scale, and correlates with relatively wetter or drier periods in the western portion of North America. • Positive PDO phases tends to enhance El Niño conditions and weaken the effects of La Niñas. • Negative PDO phases enhance the effects of La Niñas and weaken the effects of El Niños

14. http://www.ispe.arizona.edu/climas

18. Less Snow, Less Water: Climate Disruption in the West.Rocky Mountain Climate Organization, 2005 “What this work shows is that, even with a conservative climate model, current demands on water resources in many parts of the West will not be met under plausible future climate conditions – much less the demands of a larger population and a larger economy” Dr. Tim Burnett, “The Effect of Climate Change on Water Resources in the West: Introduction and Overview”

19. Likely Effects of Climate Disruption in the West • More Heat • Likely to be greater in winter than summer • Smaller Snowpacks • Winter precipitation may be more likely in the future to fall as rain rather than snow. • Earlier Snowmelt • Warming earlier in the year may melt snowpacks sooner • Increased evaporation • Increased soil dryness and evaporation from rivers and reservoirs

20. It’s Not Just the Drought, it’s the Heat

21. Snowpack Losses in the Colorado River Basin • Predicted losses of 24% by 2010-2039. • Up to 30% by 2040-2069. • Snowpack has been below average for 11 of the last 16 years.

22. What About Last Winters Precipitation? • Brought a slight reprieve from sustained drought conditions in water year 2005. • Shortage risk has been “rolled back” by about one year. • System reservoir storage is currently about what it was in 2003. • The entire Colorado River storage system decreased from 55.7 (95% capacity) to 29.7 (52% capacity) MAF from October 1, 1999 to October 1, 2004.

23. In Light of All This… • The sky is not falling. • Climate is highly variable with the only constant being variability. • Evidence of drought and climate change are likely occurring at a faster-than-anticipated rate.

24. This puts added importance on cohesive, comprehensive, and pro-active planning by water resource management agencies to ensure adequate water supplies for the foreseeable future.

25. Effect of Climate and Drought on Wildland Fires • We initiated this project prior to the Rodeo-Chedeski fire in 2002. • We were the ones to mention, and predict, long-term impacts to downstream reservoirs. • Most of these predictions have proven to be true and the reservoirs still suffer from this “re-setting” event.

26. Pre- and Post-fire Nutrient Loading

27. Increasing Hypolimnetic Anoxia in Roosevelt

28. Heat and Drought Effects on Vegetation

30. Not All Wildfires are Created Equal… • The amount of suspended sediment delivered to a river or reservoir following a wildfire depends upon several factors including local topography and vegetation type. • Some vegetation types have adapted to wildfire and require it as part of its natural succession. • Others, such as the Sonoran Desert, have likely never experienced wildfires like we have seen the last few years.

31. Cave Creek Complex and Rodeo-Chedeski Fires • Different type and amount of fuel consumed. • Rodeo-Chedeski: Huge amount of ground fuel built up for decades. • Intense, high heat fires volatilize nutrients and destroy roots, tubers, and rhizomes beneath the surface. Re-vegetation will take years – decades even with intense re-seeding efforts. • Cave Creek Complex: Oak, chaparral, brushes and grassland vegetation have evolved with frequent fire and require it for succession.

35. Wildfire and Invasive, Non-Native Plant Species • The Cave Creek Complex Fire started in the Sonoran Desert. • The Sonoran Desert never saw fire until the 1970’s when invasive plants began filling in spaces between native species. • Cave Creek Complex Fire was carried by red brome and started in an area that had previously burned the year before!

36. Native desert plants have no adaptation to wildfire. • Native plants, even when a wet winter increases their numbers many fold, lack the biomass of invading, non-native species and rarely burn. • The spread of non-native, invasive plant species is exacerbated by increasing drought, warm winters, and increasing heat and climate change.

37. Increased frequency of fire in the Sonoran Desert, kills native species and non-natives are quick to fill this niche. • The Sonoran Desert will likely look very different in a few decades and more closely resemble a savannah.

38. Watershed and Water Quality Implications • From a water quality standpoint, the real danger lies in having fires start with increased frequency at lower elevations and then spreading into higher elevations consuming more biomass and increasing in intensity. • Watershed vegetation is the “sponge” that keeps water flowing in streams and rivers and, eventually, flowing into reservoirs.

39. Summary • There will likely be changes in both water quantity and quality delivered to the Valley in the future. • The best way to ensure we have the tools needed to document these changes is through continued data acquisition. • Climate change and drought are linked to biological, physical, and chemical factors which directly affect water quantity and quality delivered to the Valley.

40. Questions?