Susanna Glaze, Bobby Creel, and Christopher Brown New Mexico State University AWRA Spring Specialty Conference 4-6 May 2009 Anchorage, Alaska

Transcription

1 Susanna Glaze, Bobby Creel, and Christopher Brown New Mexico State University 2009 AWRA Spring Specialty Conference 4-6 May 2009 Anchorage, Alaska

2 Outline Introduction to general water resources issues in Las Cruces, NM Info on climate change and New Mexico Area of investigation and research questions Data and methods Anticipated results

3 Background Water resources in the American Southwest On the whole, an arid region Sensitive to droughts and shortages Water often overallocated Population growth creating further demand

4 Las Cruces, NM Population 86,268 (as of 2006) Increase of 17.3% since 2000 Arid receiving only 8-8½ annually Most precipitation occurring during summer monsoon Prone to summer floods Primary culprits: Rio Grande (tamed by the Rio Grande Project of mid 1900s) Side channels and arroyos

5 Climate Change Increasing carbon dioxide levels are causing warming and drying in the American Southwest Process is already underway Added stress placed on water resources Profound impacts will occur in many areas

6 Climate Change From the University of Arizona Department of Geosciences Environmental Studies Laboratory.

7 Climate Change From the University of Arizona Department of Geosciences Environmental Studies Laboratory

8 Climate Change in New Mexico Rising temperatures Changes in snowpack Changes in water volume Earlier peak flows Warmer winters Hotter summers Increase in evaporation and evapotranspiration More precipitation occurring as rain, less as snow less as snow Increase in intensity of extreme weather events

9 Climate Change and Flooding When it rains it pours! Increased frequency and intensity of summer monsoon storms More precipitation falls in a shorter time span Larger amounts of runoff Flashier, more severe urban flooding

10 Climate Change and Flooding Hatch, NM 2006 From sarcher.nmsu.edu

11 Climate Change and Flooding Compounding Factors Urban Development Impervious surface Causes higher peak runoff Higher volume of runoff Faster flow Aging Infrastructure Sediment From Leopold 1968

12 Climate Change and Flooding 100-year and 500-year flood levels may need adjustment Currently based on historic climate data Flood control structures may require upgrade Some already degraded due to age

13 From NM WRRI

14 From City of From City of Las Cruces

15 Research Questions How will rainfall intensity and periodicity change in Las Cruces under climate change? If there is an increase in rainfall intensity, how will it affect flooding dynamics? Will we see more flood events, higher stages, storm hydrographs exceeding channel capacity, or all of the above? Can the current flood infrastructure accommodate potential future increases in runoff due to climate change and land-use change? What changes or improvements should be made to allow infrastructure to accommodate projected future flood flows?

16 Methods & Data Based on a framework created by Catherine Denault, Robert G. Millar, and Barbara J. Lence in 2006 Assessment of Possible Impacts of Climate Change in an Urban Catchment. Journal of the American Water Resources Association 42(3):

17 Methods & Data Analyze past rainfall intensity for trends Data needed: Rainfall intensity it data for different durations (5min, 10min, 15min, 1hr, etc) for Las Cruces Data should cover enough time to ensure statistically significant results Only summer monsoon data will be used Linear regression will be used to test for trends

18 Methods & Data Extrapolate to the future Any trendlines of statistical significance will be used to create future Intensity-Duration- ti Frequency (IDF) curves Linear regression will be used to extrapolate to two future years, 2025 and IDF curves will be used to create future synthetic storms to be modeled in SWMM

19 Methods & Data SWMM5 EPA s StormWater Management Model Used to model storm runoff in an urban setting Uses topography, sewer system layout, soil attributes, slope, and land use change data Can model single events or long term changes

20 Methods & Data Synthetic storms created from trendlines found will be used in SWMM Simulations will be ran SWMM will pinpoint which structures will be able to accommodate increases, which will fail

21 Anticipated Outcomes Trendlines of statistical significance are expected to be found Future rainfall scenarios will cause flashier floods Some structures will pass, some will fail

22 Acknowledgements Funding provided by Vice President of Research, New Mexico State University Graduate Research Enhancement Program and NM Water Resources Research Institute

23 Questions or Feedback??