USDA-ARS Southwest Watershed Research Center SWRC Mission Sound Science for Watershed Decisions To develop knowledge and technology to conserve water and soil in semi arid lands ARS Research In General 1. Problem solving, as opposed to curiosity driven 2. Long term, as opposed to 3 year grant cycles 3. Regional and national, as opposed to local and state level 4. High risk and high impact Selected Accomplishments from Walnut Gulch Precipitation Analyses Flood Frequency Transmission Losses Hydrologic Instrumentation Erosion and Sediment Transport Developing Natural Resource Simulation Models Data and Data Access
ARS Watershed Locations Scope of the research unit Ken won the Tipton Award for foundational contributions such as: In 2012, Ken Renard won 2 national lifetime awards, the Tipton Award by the American Society of Civil Engineers, and the Hugh Hammond Bennett Award from the Soil and Water Conservation Society. Hydrology Handbook. Manuals and Reports on Engineering Practice No. 28, ASCE Task Comm. on Hydrology Handbook of Manage. Group D, 784 p. Urban Subsurface Drainage Manual. ASCE Manual of Engineering Practice, Final Draft, Prepared by the Urban Drainage Standards Committee, Codes and Standards Activities Comm. (CSAC), Technical Activities Comm. (TAC), 195. Soil and Water Quality: An Agenda for Agriculture, J. Overton (ed.) Comm. on Long Range Soil and Water Conservation, Board on Agric., National Res. Council, National Academy Press, Washington, DC, 516 p. Rangeland Hydrology. Range Science Series No. 1, 2nd Ed., Soc. for Range Manage., 352 p. Runoff. Chapter 2 In: USDA SEA, Agric. Handbook 224, pp. 75 214.
Ken won the Hugh Hammond Bennett Award for: Establishing and running the Walnut Gulch Experimental Watershed Leading the development, over a decade, of the Revised Universal Soil Loss Equation (RUSLE). A = RKLSCP A = average annual soil loss from rill and interrill erosion R = climate erodibility K = soil erodibility measured under a standard condition L = slope length S = slope steepness C = cover management P = support practices Grassland Brush Tombstone Walnut Gulch Experimental Watershed 0 2 4 6 8 10 Kilometers Improved Quantification of Semiarid Water Budget Components Runoff Unit Source Area Runoff Large Watersheds 10 watersheds.2 4.4 ha Evaluate the effects of soil, vegetation, rainfall intensity Event hydrographs 10 watersheds 2 150 km 2 Evaluate the effects of channel network, spatial distribution of rainfall Event Hydrographs Flume 103 Flume 6
Percentage Difference Between 1999 2010 Gage Mean and Watershed Mean Cochise County temperature trend indicates an increase of.25 degrees C per decade in maximum temperatures and.29 degrees C per decade in the minimum Temperatures. Results are based on 10 stations (Bowie, Douglas Intl Airport, Coronado Nat Mon, Chiricahua Nat Mon, McNeal, Portal, San Simon, Willcox, Y Lightning Ranch, and Tombstone). From Utilizing Long Term ARS Data to Compare and Contrast Hydroclimatic Trends from Snow and Rainfall Dominated Watersheds by D.C. Goodrich et al. (2011). 401 SWRC Measured Variables 1953 2012 351 301 251 WGEW 201 SRER USPP SWRC 151 101 51 1 1950 1960 1970 1980 1990 2000 2010 2020
Contributions of Walnut Gulch Experimental Watershed and SWRC Precipitation Runoff Erosion and Sedimentation Carbon and Water Fluxes Understand Process Rainfall Simulation Model Process Manipulate Process Contributions of Walnut Gulch Experimental Watershed and SWRC Precipitation Runoff Erosion and Sedimentation Model RUSLE Understand Manipulate NRCS Conservation Programs Local / State Regional / National ~$3B annually in cons. programs World See Map WEPP Road design Remediation Forest Service Rocky Flats? RHEM Conservation Programs Not Adopted Yet None
Dave Goodrich, Research Hydraulic Engineer Active in San Pedro Studies, Kineros model and AGWA tool National Weather Service is testing Kineros for small watershed flood forecasting in Tucson, AZ; Pittsburgh, PA; La Crosse, WI; Kansas City, MO; Binghamton, NY; and Portland, OR. Improved Watershed Modeling Capabilities Urban rural interface element combinations of various runoff run on combinations Surface Water Hydrologic Modeling Incorporation of Remotely Sensed and GIS Data into Hydro Models Improved modeling of water quality and Best Management Practices (BMP s) Integration of Research with Elected Officials and Decision Makers The AGWA (Automated Geospatial Watershed Assessment) Tool The AGWA delineation of buffer strip BMP model elements in KINEROS2 Susan Moran, Hydrologist Irrigated Crops, soil moisture, remote sensing Vegetation Temperature Soil Surface Roughness Soil Moisture & Water Deficit Index CO 2 Fluxes Remote Sensing Dr. Moran
Surface Soil Moisture (m 3 / m 3 in top 5 cm) Walnut Gulch boundary Surface Soil Moisture Value High : 0.4 Net Daytime CO 2 Flux (g m 2 (12 h) 1 ) From WDI (vegetation & temperature), calculations of instantaneous fluxes, and daily flux measurements Low : 0.0 < 0 0 1.99 2 3.99 4 5.99 6 7.99 8 9.99 9/30/92 9/17/93 10 11.99 12 13.99 14 15.99 16 17.99 18 19.99 > 20 g m 2 (12 hrs) 1 Rahman et al. 2005 8/30/98 9/26/99 Holifield et al. 2004 Russ Scott, Hydrologist Evapotranspiration, Carbon and Energy Fluxes Fluxes Micrometeorological and ecophysiological techniques are used better understand and quantify ecosystem energy, water and carbon dioxide exchanges in order to: Savanna Creosote Shrubland quantify riparian water use and improve basin surface and ground water budgets understand the interactions between CO 2 and water cycles in semiarid regions Grassland Grassland determine the ecohydrologic consequences of woody plant encroachment SWRC operates an array of eddy covariance towers placed throughout southern Arizona to address a number of issues related the functioning of ecosystems in semiarid areas. Riparian Woodland Riparian Grassland and Shrubland
Erik Hamerlynck, Biologist 18 Ecology, physiology, plant water and carbon issues Daily soil carbon efflux (g m -2 ) 16 14 12 10 8 6 4 2 0 Under shrub Open interspace 4/9 4/16 4/23 4/30 5/7 5/14 5/21 Date Mary Nichols, Res. Hydraulic Engineer Rangeland Soil Conservation Research To quantify the impacts of conservation practices on: sediment retention soil moisture vegetation With respect to: design landscape position rainfall/runoff water control berms loose rock dams Soil conservation, sediment budgets, photography Jeff Stone, Hydrologist Runoff and Erosion Processes Variable intensity (25 180 mm/hr) Small (0.75 m 2 ) and Large (2x6 m) plots Providing new fundamental knowledge on rangeland hydrologic response and erosion processes Semi arid grassland, shrub, and oak woodland sites State and Transition models Grazing and Fire Runoff and Erosion Rainfall Simulation, hydrologic modeling
Partial Area Response Spatial Heterogeneity Infiltration and Runoff Steady state infiltration increases with rainfall intensity Erosion Partial area response raindrop detachment, deposition Entire area response potential flow detachment and continuous transport infiltration rate (mm/hr) 120 100 80 60 40 20 0 0 50 100 150 200 rainfall rate (mm/hr) Undisturbed Disturbed qs (g/s) 8 6 4 2 0 Undisturbed Fire Heavy grazing 0.0 0.2 0.4 0.6 0.8 1.0 contributing area Mark Nearing, Agricultural Engineer Erosion and sediment issues, effect of climate change on erosion Methods: Cesium 137 and Rare Earth Element Tracers S Lucky Hills, WG Shrub Area
Phil Heilman, Research Leader Decision Support, Remote Sensing Cover Comparison: Ground vs Satellite Arizona and New Mexico 2010 i cubed 15m esat Imagery Cover Images 2010 30m Landsat 60% Cover: 5% measured 10% Landsat (ID: 123 0.022) Cover: 5% measured 12% Landsat (ID: 59 0.030) Cover: 10% measured 14% Landsat (ID: 115 0.042) Cover: 17% measured 22% Landsat (ID: 54 0.094) 0% 2010 500m MODIS Upper San Pedro Partnership (USPP) USPP Goal: Assuring an adequate long term groundwater supply is available to meet the reasonable needs of both the area s residents and property owners (current and future) and the San Pedro National Riparian Conservation Area
For the first time, instantaneous rainfall rate fields (snapshots) from TRMM Radar (PR) are compared with those of a dense gauge network (of 1 min accumulations). Instantaneous comparisons avoid satellite temporal sampling errors. The network, located at the USDA/ARS Walnut Gulch Experimental Watershed in south east Arizona, consists 88 gauges within 149 km 2 (~10 gauges per PR footprint of 5 km diameter), the densest gauge network in the PR coverage area for watersheds > 10 km 2. All TRMM overpasses in which the PR recorded rain within the watershed are analyzed (25 overpasses during 1999 2010). Very good agreement between the PR and the interpolated gauge rain rate fields with highcorrelation and low bias values (<10%), especially for the near nadir cases (CC>0.9). Correlations this high are typically not observed when comparing remote sensing observations (e.g., satellite vs. ground radar, gauge vs. ground radar). Agreement improves using the new released TRMM products (V7) compared to V6. Correlation peak occurs several minutes after the overpass, as it takes several minutes for the raindropstoreachthegaugefromthetimethey are observed by the PR. Earth Sciences Division Atmospheres Dense Gauge Network Confirms Improvement in TRMM Radar Rainfall Intensity Estimates Eyal Amitai, Code 612, NASA GSFC and Chapman University V7 V7 V6 V6 & V7 V6 Figure 1: The rain rate field over the Walnut Gulch watershed as observed by the TRMM PR on 4 Oct 2001 @ 0129 UTC based on version 7 (upper left) and version 6 (upper right) rainfall retrieval algorithms. The watershed interpolated gauge rainfall rate field at 10 min after the overpass (left panel). Each PR footprint is illustrated schematically by a 5 km diameter circle. Each of the 88 gauges is marked by a red dot. Figure 2: Correlation coefficients (red curves) between the TRMM PR footprint and the colocated interpolated gauge (G) area average rain rate. The PR/G ratio of average rain rate is also shown (blue curves) for every minute during an hour