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Sound Science for Watershed Decisions
USDA-ARS
Southwest Watershed Research Center
SWRC Mission
• 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
Scope of the research unit
ARS Watershed Locations
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 WaterConservation Society.
Ken won the Tipton Award for foundational contributions such as:
• 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 = RKLSCPA = average annual soil loss from rill and interrill erosionR = climate erodibilityK = soil erodibility measured under a standard conditionL = slope lengthS = slope steepnessC = cover managementP = support practices
Walnut GulchExperimental Watershed
Kilometers
Grassland
Brush
0 2 4 6 8 10
Tombstone
Improved Quantification of Semiarid Water Budget Components
Runoff ‐ Unit Source Area
• 10 watersheds
• .2 ‐ 4.4 ha
• Evaluate the effects of soil, vegetation, rainfall intensity
• Event hydrographs
Flume 103
Runoff ‐ Large Watersheds
• 10 watersheds
• 2 ‐ 150 km2
• Evaluate the effects of channel network, spatial distribution of rainfall
• Event Hydrographs
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 minimumTemperatures. 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 Watershedsby D.C. Goodrich et al. (2011).
1
51
101
151
201
251
301
351
401
1950 1960 1970 1980 1990 2000 2010 2020
SWRC Measured Variables 1953‐2012
WGEW
SRER
USPP
SWRC
Contributions of Walnut Gulch Experimental Watershed and SWRC
UnderstandProcess
ModelProcess
ManipulateProcess
Precipitation
Runoff Rainfall Simulation
Erosion and Sedimentation
Carbon and Water Fluxes
Contributions of Walnut Gulch Experimental Watershed and SWRC
Under‐stand
Model Mani‐pulate
Local / State
Regional /National
World
Precipitation
Runoff
Erosion and Sedimentation
RUSLE
WEPP
RHEM
NRCS Conserv‐ationPrograms
Road designRemed‐iation
Conserv‐ationPrograms
~$3B annually in cons. programs
Forest ServiceRocky Flats
Not Adopted Yet
See Map
?
None
Dave Goodrich, Research Hydraulic Engineer
Active in San Pedro Studies, Kineros model and AGWA tool
National Weather Service is testingKineros 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
– 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
Urban‐rural interface element – combinations of various runoff – run‐on combinations
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
Remote Sensing
• Vegetation
• Temperature
• Soil Surface Roughness
• Soil Moisture & Water Deficit Index
• CO2 Fluxes Dr. Moran
Surface Soil Moisture(m3/ m3 in top 5 cm)
Walnut Gulch boundary
Surface Soil Moisture
Value
High : 0.4
Low : 0.0
Rahman et al. 2005
< 0
0 – 1.99
2 – 3.99
4 – 5.99
6 – 7.99
8 – 9.99
10 –11.99
12 – 13.99
14 – 15.99
16 – 17.99
18 – 19.99
> 20
g m‐2 (12 hrs)‐1
9/30/92 9/17/93
8/30/98 9/26/99
Net Daytime CO2 Flux(g m‐2 (12 h)‐1)
Holifield et al. 2004
From WDI (vegetation & temperature), calculations of instantaneous fluxes, and daily flux measurements
Russ Scott, Hydrologist
Evapotranspiration, Carbon and Energy Fluxes
Micrometeorological and eco‐physiological techniques are used better understand and quantify ecosystem energy, water and carbon dioxide exchanges in order to:
‐quantify riparian water use and improve basin surface andground water budgets
‐understand the interactionsbetween CO2 and water cycles in semiarid regions
‐determine the ecohydrologicconsequences of woody plantencroachment
Fluxes
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.
Creosote Shrubland
Grassland
Riparian Woodland
Savanna
Grassland
Riparian Grassland and Shrubland
Erik Hamerlynck, Biologist
Ecology, physiology, plant water and carbon issues
Date
4/9 4/16 4/23 4/30 5/7 5/14 5/21
Dai
ly s
oil c
arbo
n ef
flux
(g m
-2)
0
2
4
6
8
10
12
14
16
18
Under shrubOpen interspace
Mary Nichols, Res. Hydraulic Engineer
Soil conservation, sediment budgets, photography
Rangeland Soil Conservation Research
loose rock dams
water control berms
To quantify the impacts ofconservation practices on:
sediment retentionsoil moisturevegetation
With respect to:
designlandscape positionrainfall/runoff
Jeff Stone, Hydrologist
Rainfall Simulation, hydrologic modeling
Runoff and Erosion Processes
Variable intensity (25‐180 mm/hr)
Small (0.75 m2) and Large (2x6 m) plots
Semi‐arid grassland, shrub, and oak woodland sites
State and Transition models
Grazing and Fire
Runoff and Erosion
Providing new fundamental knowledge on rangeland hydrologic response and erosion processes
Partial Area ResponseSpatial Heterogeneity
Infiltration and Runoff
Steady state infiltration increases with rainfall intensity
0
2
4
6
8
0.0 0.2 0.4 0.6 0.8 1.0
contributing area
qs (
g/s
)
0
20
40
60
80
100
120
0 50 100 150 200
rainfall rate (mm/hr)
infi
ltra
tio
n r
ate
(mm
/hr)
Undisturbed
Disturbed
Undisturbed
Fire
Heavy grazing
Erosion
Partial area response – raindrop detachment, deposition
Entire area response– potential flow detachment and continuous transport
Mark Nearing, Agricultural Engineer
Erosion and sediment issues, effect of climate change on erosion
Methods: Cesium 137 and Rare Earth Element Tracers
Lucky Hills, WGShrub Area
S
Phil Heilman, Research Leader
Decision Support, Remote Sensing
Cover Comparison: Ground vs SatelliteArizona and New Mexico 2010
Cover:• 5% measured•10% Landsat(ID: 123‐0.022)
Cover:• 5% measured•12% Landsat(ID: 59‐0.030)
Cover:• 17% measured•22% Landsat(ID: 54‐0.094)
Cover:•10% measured•14% Landsat(ID: 115‐0.042)
Cover Imagesi‐cubed 15m eSAT Imagery
2010 30m Landsat
2010 500m MODIS
60%
0%
‘‘ 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”
Dense Gauge Network Confirms Improvement in
TRMM Radar Rainfall Intensity Estimates
Eyal Amitai, Code 612, NASA GSFC and Chapman University
For the first time, instantaneous rainfall rate fields(snapshots) from TRMM Radar (PR) are comparedwith those of a dense gauge network (of 1‐minaccumulations). Instantaneous comparisons avoidsatellite temporal sampling errors. The network,located at the USDA/ARS Walnut GulchExperimental Watershed in south‐east Arizona,consists 88 gauges within 149‐km2 (~10 gauges perPR footprint of 5‐km diameter), the densest gaugenetwork in the PR coverage area for watersheds >10‐km2. All TRMM overpasses in which the PRrecorded rain within the watershed are analyzed(25 overpasses during 1999‐2010).
• Very good agreement between the PR and theinterpolated gauge rain rate fields with high‐correlation and low‐bias values (<10%), especiallyfor the near‐nadir cases (CC>0.9).
• Correlations this high are typically not observedwhen comparing remote sensing observations(e.g., satellite vs. ground radar, gauge vs. groundradar).
• Agreement improves using the new releasedTRMM products (V7) compared to V6.
• Correlation peak occurs several minutes afterthe overpass, as it takes several minutes for theraindrops to reach the gauge from the time theyare observed by the PR.
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 co‐located 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
V6V7
V6 & V7
V7 V6
Earth Sciences Division ‐ Atmospheres