Impacts of changes in climate and land use on hydrology of the Flint River

Transcription

1 Impacts of changes in climate and land use on hydrology of the Flint River Geospatial Research and Education Center (GREC) USDA NIFA Anil Acharya Department of Mechanical and Civil Engineering Alabama A&M University (Sep. 10, ) 1

2 Introduction Study Area Methods Results Future Work 2

3 Introduction Climate change around this globe is expected to have higher impact on water resources Increase in the frequency of floods and droughts. Varying Intensities. Various studies have been conducted at different parts of the world which relates to impacts of climate change on water quantity/quality (streamflow/runoff/groundwater recharge/extreme events), irrigation, agriculture, energy, food production/ security, industry/domestic use, ecology/biodiversity, environmental, and economic aspects. Evaluate individual and combined impacts of climate change and land use change in the Flint River (FR). 3

4 Study Area WLW drains approximately 2876 sq. miles to the Tennessee River (TDEC, ) Flint River Watershed Alabama Mesonet Stations in the upper regions of the watershed and in operation since ALMNet: Also a part of USDA NRCS Soil Climate Analysis Network (SCAN) and operated by AAMU. Only one stream gage station located at Brownsboro (USGS ) 4

5 Impact Evaluation Methodology WCRP CMIP5 ensemble that consists of 234 downscaled climate projections from four emission scenarios and 37 GCMs. 5

6 Results: Observed vs GCM Modeled Average monthly temperature in the range of 4.8 C to 25 C. Monthly and Total annual precipitation from GCM output almost similar for all scenarios. Modeled precipitation comparatively higher than observed precipitation for all months except August, Oct and Dec. Modeled precipitation is in the range of mm/day while the observed precipitation is in the range of mm/day. 6

7 Results: Future Climate Pattern Range of change of temperature ( C) calculated to be (2030s), (2050s), (2070s), and (2090s). Range of change of precipitation (%) calculated to be to 6.94 (2030s), to (2050s), to (2070s), and -6.49% to 22.19% (2090s). 7

8 Results: Model Calibration Model calibration and validation ( ) at a monthly time steps. (r = 0.97/0.86; R 2 = 0.93/0.73; Bias (%) =19%; RMSE = 5.6/8.9 cms). 8

9 Results: Monthly Streamflow Increasing streamflow pattern during Feb-June and decreasing pattern for other months (Feb- max increase; August max decrease). Change in monthly streamflow from +23% to -46%, +29% to -48%, +40% to -48%, +38% to -48% for scenarios RCP 2.6, 4.5, 6.0, and 8.5 respectively. Average change in monthly streamflow for the entire year shows a decreasing pattern in the range of -5% to -11%, -3% to -7%, +1% to -5%, and -+1% to -5% for scenarios RCP 2.6, 4.5, 6.0, and 8.5 respectively. 9

10 Results: Annual Total Streamflow Change in total annual streamflow in the range of +7% to -28%, +13% to -17%, +17% to - 13%, +18% to -15% (RCP 2.6, 4.5, 6.0, and 8.5). Average change in total annual streamflow based on all emission scenarios: +10% to -16%, +12% to -14%, +11% to -15%, and +13% to -14% for periods 2030s, 2050s, 2070s, and 2090s respectively; Average change for all scenarios shows a decreasing pattern in the range of -0.3% to -1.2% for future periods except during 2090s which shows a slight increase of 0.17% for the annual total streamflow. All scenarios except RCP 2.6 shows an increase in annual total streamflow from 1% to 4.2% during 2090s. 10

11 Results: Land Use Change NLCD land cover classification for the FRW during 2006 and 2011 Legend reclassify11 Value Land Use/Land Cover 1 Water/Wetlands 2 Urban 3 Barren/Mining 4 Forest 5 Upland/ShrubLand 6 Agriculture/Cropland 7 GrassLand 8 Agriculture-Pasture 11

12 Results: Monthly and Annual Streamflow Land Use Change Scenarios For change from RNGE to Urban High Residential (For RCP 2.6 and 2030s) Change in monthly streamflow from -0.25% to 0.45%, -0.35% to 0.7%, and -0.8% to 1.2% for 3%, 5%, and 10% change in land cover. Average change in monthly streamflow for the entire year as 0.07%, 0.12%, 0.24%. Annual maximum and minimum change from to 0.46%, to 0.77%, and to 1.5% for 3%, 5%, and 12 10% change in land cover.

13 FUTURE WORKS More realistic hypothetical land use change scenarios for future periods. Extend similar analysis on hydrological impact evaluation to other subwatersheds within the wheeler lake watershed. ACKNOWLEDGEMENTS USDA-NIFA Dr. Wubishet Tadessee and Dr. Dawn Lemke Kyle Majors (UG/Graduate Student at Duke), Chadz Taylor (UG) 13

14 Questions??? 14

15 15

16 16