Assessing the hydrologic and water quality impacts of climate change in small agricultural basins of the Upper Chesapeake Bay watershed Anthony Buda USDA Agricultural Research Service Monday, March 7, 2016 Westin Hotel Annapolis, MD The Development of Climate Projections for Use 1:40 to 2:00 PM in Chesapeake Bay Program Assessments Today’s presentation Upper Chesapeake Bay climate assessment Upper Chesapeake LTAR A brief overview of the four basins comprising the Upper Chesapeake LTAR location in Pennsylvania. Climate change projections Future climate predictions for the Mahantango Creek basin using statistically downscaled data. Modeling hydrology and water quality An approach to predicting the effects of climate change on hydrology and water quality with the SWAT model. USDA’s LTAR Network serving as a sentinel to changes in climate and hydrology Northern Great Plains Heartland Northern Crescent R.J. Cook Agronomy Farm Northern Plains Great Basin Kellogg Upper Mississippi Upper Chesapeake Bay Biological Station Central Plains Platte River River Basin Eastern Experimental Range High Plains Aquifer Central Mississippi Corn Belt Lower Chesapeake Bay River Basin Eastern Uplands Southern Lower Mississippi Plains Southern Seaboard Walnut Gulch Jornada River Basin Gulf Atlantic Experimental Watershed Experimental Range Southern Coastal Plain Fruitful Rim Plains Archbold Basin and Range Biological Station Prairie Gateway Mississippi Portal LTAR Shared Research Strategy, 2013 Upper Chesapeake Bay LTAR Four basins typifying variable physiography and farming Anderson Creek Watershed Rockton, PA Anderson Allegheny Creek Plateau Spring Creek Watershed Rock Springs, PA Mahantango Spring Ridge & Creek Creek Valley Piedmont Conewago Creek Mahantango Creek Watershed Klingerstown, PA Coastal Plain Conewago Creek Watershed Elizabethtown, PA The Mahantango Creek Watershed an ideal place to assess long-term trends in hydroclimate Precipitation (1968 to present) WE-38 Watershed (7.3 km2) Temperature (1978 to present) Streamflow (1968 to present) Buda et al., 2011a, b (WRR) Significant hydroclimatic trends in WE-38 Steadily rising temperatures and a lengthening growing season are Annual 0.38 C mean temp. per decade consistent with a warming climate. At the basin level, evapotranspiration Annual 37 mm increases represent the clearest change AET per decade in hydroclimate over the past 45 years. More intense rain storms in the fall have led to augmented streamflow during a Tropical Storm Lee time when flows are normally low. Snowmelt runoff events are declining in Flood of winter whereas in summer, low flow 1996 periods are expanding in duration. Climate change in the Upper Chesapeake Using downscaled data to project future climatic conditions Regional models disaggregated to 1/16 Anderson Creek Mahantango Spring Creek Creek Conewago Creek Downscale 9 models from the Mahantango Creek watershed Coupled Model Inter- WE-38 comparison Project Phase 5 (CMIP5) for the business as usual (RCP 8.5) and stabilization (RCP 4.5) emissions pathways. Hayhoe et al., 2007 (Climate Dynamics); Stoner et al., 2013 (International J. Climatology) We obtained climate projections from nine different climate models Climate models recommended by Katharine Hayhoe CCSM4 HadGEM2-CC inmcm4 CSIRO-Mk3-6-0 CNRM-CM5 MIROC5 IPSL-CM5A-LR MRI-CGCM3 MPI-ESM-LR International Centre for Earth Simulation Daily climate variables Mean temp. (C) Max temp. (C) Min temp. (C) Solar radiation (MJ/m2) Precip. (mm) Wind speed (m/s) Mid-century temperatures will be warmer with increases of about 2C relative to 1960-1989 Hadley Centre Climate Model Version 3 (HadCM3) Mean annual temperature 20 Mahantango C) Creek 15 10 5 Temp. ( Temp. 0 1950 2000 2050 2100 Mid-century (2015 to 2044) increase in mean annual temperature F 3.0 3.5 4.0 C 1.67 1.94 2.22 A warmer climate means more extremes daily max temperatures may approach 42C by century’s end 60 C) 50 40 30 Highest daily max Highest daily max Highest daily max 20 temp in 1975 temp in 2025 temp in 2075 35 (3)C 37 (4) C 42 (6) C 10 Annual max value of daily max temp. ( of temp. max daily value Annual max 0 1950 1975 2000 2025 2050 2075 2100 Year Mid-century will be wetter increases will range from 5 to 15% relative to 1960-1989 Hadley Centre Climate Model Version 3 (HadCM3) Mean annual precipitation 2000 Mahantango Creek mm) . ( 1000 0 Precip 1950 2000 2050 2100 Mid-century (2015 to 2044) increase in mean annual precipitation % 5 10 15 Daily rains of 25 mm will be more routine with 5 more such days by the year 2100 25 20 15 10 5 Days per year with rainfall > 25 mm with rainfall per year Days 0 1950 1975 2000 2025 2050 2075 2100 Year More frequent 20-yr storms (127 mm/d) with a 3-fold increase in frequency expected by 2100 Northeast By late century, events that recurred once in 20 years may happen three to four times as often. Future change multiplier 1 2 3 4 5 6 7 Wuebbles et al., 2014 (BAMS); US National Climate Assessment, 2014 Paradoxically, the future also could be drier Evaporative demand is likely to overwhelm inputs from rain Longer dry spells Increased risk of drought Northeast Change in max consecutive dry days (%) Standardized soil moisture (0-30 cm; deviations from 20th century mean) for 2090 to 2099 using the RCP 8.5 emissions scenario (Cook et al., 2015; Science Advances). More than 80% of climate Take home point: more rain is needed models suggest that successive to keep pace with rising evaporative dry days will rise by 5 to 10%. demand (Sherwood and Fu, 2014). US National Climate Assessment, 2014; Sherwood and Fu, 2014 Implications for the Upper Chesapeake Simulating potential climate change impacts in small basins 30 ) • Emissions scenarios RCP 4.5 and 8.5 yr 25 20 • Three time frames 15 1. Early century (2015 to 2034) emissions 10 2 2. Mid century (2045 to 2064) CO 5 3. Late century (2081 to 2100) 0 (billion (billion tons/ metric 1950 1975 2000 2025 2050 2075 2100 Topo-SWAT (Easton et al., 2008) Improved simulation of variable source area (VSA) hydrology in agricultural watersheds of the humid Northeast. Climate change and watershed hydrology How will the water balance change with climate change? 1400 1200 1000 Precipitation 800 600 400 Streamflow 200 Precipitation or streamflow depth (mm) or streamflow Precipitation 0 1950 1975 2000 2025 2050 2075 2100 Year Climate change and watershed hydrology How will climate change affect runoff generation patterns? Using Topo-SWAT to identify variable source areas (VSAs) Runoff (mm) 400 500 600 700 800 Mattern Watershed runoff 22,000 L 90 L well drained soil Mattern poorly drained soil (restrictive layer) SWAT images courtesy of Tamie Veith and Amy Collick Climate change and watershed hydrology How will the frequency of floods and low flows change? 100 10 Will the flow duration curve ) shift with climate change? cms 1 0.1 Mean daily flow Mean flow ( daily 0.01 High flow Low flow 0.001 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Percentage of time equaled or exceeded Climate change and water quality Effects of current climate and land use on water quality Converted Converted ConvertedForested Forested Grass Current land management basedForestedGrass on farmer surveys None GrassNone NoneConverted PerennializationConverted ForestedCGAA Forested CGAAGrassCPSTForested buffer GrassGrass buffer CPSTNone NoneNone GRFL ConservationGRFLCGAA Cropping CGAA CPSTDGABCover crops CPST DGAB No till EGAB GRFL DGABEGABConservation tillage EGAC EGAB EGAC BaselineFGAC land use EGACDGABEGABFGAC LU_WE38_currentNo change in mgmt. FGAC EGACLU_WE38_current LU_WE38_currentEGABFGAC EGACLU_WE38_current SimulateFGAC N, P, and sediment losses in runoff LU_WE38_current Images courtesy of Tamie Veith and Amy Collick Climate change and water quality None Relative effects of climate and land useGrass change on water quality Converted ConvertedForested ConvertedForested ForestedConverted ForestedGrass Land mgmt. and BMP allocation usingGrassLU_WE38_manureinj PA’s WIP (thru 2025) None GrassNone LU_WE38_CoverCrops Converted NoneConverted Farm InfrastructureConvertedForestedLU_WE38_GravelRoads ForestedCGAA ForestedLU_WE38_FarmStrcBarnyard runoff CGAAGrassCPST GrassLU_WE38_NoTill PerennializationCPSTNone NoneLU_WE38_MinTill Converted GRFLGrass/forested buffer GrassGRFLCGAA Forested buffer CGAAGRFL Forested CPSTDGABGrass buffer CPST None LU_WE38_scenarios DGAB None EGAB LU_WE38_manureinj GRFLTree planting DGABEGAB EGAC LU_WE38_CoverCrops ConservationEGAB EGAC Cropping LU_WE38_GravelRoadsFGAC NoneEGACDGABEGABFGAC LU_WE38_FarmStrcLU_WE38_currentCover crops GrassFGAC EGACLU_WE38_current LU_WE38_NoTillNoneNo till ForestedLU_WE38_currentEGABFGAC LU_WE38_MinTillGrassConservation tillage ConvertedEGACLU_WE38_current Forested Manure/NutrientLU_WE38_covercropsFGAC Management GRFLConverted LU_WE38_manureinjLU_WE38_currentManure injection LU_WE38_scenariosLU_WE38_manureinj LU_WE38_NoTill Urban StormwaterLU_WE38_CoverCropsManagement LU_WE38_MinTill LU_WE38_GravelRoads Gravel road improvement LU_WE38_FarmStrc BaselineGRFL land use LU_WE38_NoTill LU_WE38_scenariosNo change in mgmt. Images courtesy of Tamie Veith and Amy Collick LU_WE38_MinTill GRFL LU_WE38_scenarios Acknowledgments Ray Bryant, Peter Kleinman, Amy Collick, Gordon Folmar, Sarah Goslee, Tamie Veith, Al Rotz Anne Stoner Katharine Hayhoe.