Preliminary Applications of the HL-RDHM within the Colorado Basin River Forecast Center

1
Preliminary Applications of the HL-RDHM within
the Colorado Basin River Forecast Center
Ed Clark, Hydrologist Presented July 26th, 2007
as part of the WR Field Hydrology Seminar Series
2
NWS Distributed Model(s)
RDHM Research Distributed Hydrologic
ModelObject oriented with SAC-SMA, Snow17, API,
Frozen Ground, Channel Shape, and Routing Curve
sub-routines
Output Grids -- Any parameters states Time
Series Basin Average (any parameter) and Outlet
Discharge.
DHM NWSRFS OperationRequires RDHM to setup
parameter grids. Limited to SAC-SMA model and
routing via the connectivity file. Delivered to
the RFCs in build 8.2.
Output Discharge time-series for display within
NWSRFS
3
Model Structure

• Divides the basin of interest into 4 km2 grids.
  (HRAP)
• Requires gridded Surface Temperature and
  Precipitation (xmrgs from MPE).
• Runs modules the existing models Snow17,
  Sacramento Soil Moisture Accounting Model
  (SAC-SMA) to generate runoff.
• Runoff is routed by solving the Kinematic Wave
  Equations.

4
(No Transcript)
5
Model Concept The HL-RDHM is an object oriented
modeling system consisting of Snow Melt, Rainfall
Runoff, Frozen Ground models and routing methods.
Individual modules are called from within the
RDHM architecture. Invoking any of the modules
allows their parameters and states to be access
by other modules from the three dimensional array
or PixGraph.
Snow17
Surface and subsurface flow
Runoff
6
Evapotranspiration

• Mean Monthly PE and PE_adj grids.
• Mean Daily PE grids derived from point data and
• PE_adj grids derived from Green Vegetation
  Fraction (NCEP global data set) and derived
  through the an empirical relationship with the
  calibration process.

7
Channel and Hill-slope routing
Real HRAP Cell
Hillslope model
Cell-to-cell channel routing
From Yu Zhang, OHD
8
Control and Calibration

• Input card is passed to the model. Defines
  location of data, simulation period, and
  calibration parameters.
• Parameters grids can be calibrated by multiplying
  the by a scalar.

gt1
Gridded Parameter
lt1
9
Model Parameterization

• Snow17 MFMax and MFMin based on DEM analysis,
  provided by OHD.
• SAC-SMA grids provided by OHD and based on
  STATSGO data.
• Routing grids are generated from USGS field
  measurements by defining a relationship between
  channel shape and discharge.
• Other grids written out from the calibrated
  lumped model.

10
Evolution to a Fully Distributed Model
Sac_LZTWM

• Lumped Model. Extensively calibrated for the
  CBRFC with a great deal of forecaster skill.
• Lumped parameter values distributed by elevation
  zone. Used to check the mechanics of the model,
  and increase forecast skill with high intensity,
  convective events.
• Fully Distributed. Parameters based on Statsgo
  data, calibrated by applying a scalar multiplier,
  High Spatial Variability

past
Future
11
Application/Demonstration Basins

• Comparison w/ RTi SNOWDAS.
• Gridded Snow17 Investigation
• Demonstration of gridded soil moisture norms
  and QPE driven small basin hydrograph. Verde,
  Santa Cruz and San Pedro basins.

12
Rapid surface-runoff and near surface soil
moisture

• Does spatially distributing convective
  precipitation help improve our ability to
  simulate hydrographs in arid portions of the
  Southwest?
• Can the gridded Sac-SMA model be used to qualify
  the current conditions of near-surface soil
  moisture?

13
QPE driven small basin hydrograph flash
flooding quantification.
MPE xmrgs and scaled (calibrated lumped to
a-priori basin mean) OHD a-priori sac-sma grids
14
MPE xmrgs and scaled (calibrated lumped to
a-priori basin mean) OHD a-priori sac-sma grids
15
Normalized Soil Moisture

• Generate mean upper and lower tension water
  contents from the lumped model calibration.
• Compare the RDHM output tension water contents to
  this days normal conditions.
• Asks, where are we today compared to where we are
  usually?

16
Seasonal Soil Moisture Simulation in the Upper
Verde River
April 1st, 2007
May 1st, 2007
June 1st, 2007
July 1st, 2007
July 14th, 2007
July 21st, 2007
17
Soil Moisture Percent of Normal
July 1, 2006
Upper Zone
Lower Zone
18
Soil Moisture Percent of Normal
July 25, 2006
Upper Zone
Lower Zone
19
Prototype Upper Zone NormalAug 20th, 2007
20
Prototype Lower Zone NormalAug 20th, 2007
21
Contents at Depth

• Utilizes Victor Korens Sacramento Heat Transfer
  (SAC-HT) model.
• Calculates frozen and liquid contents in a set of
  computational layers at specified depths.
• Outputs as outlet time-series or individual
  grids.

22
Lower Santa Cruz (at Laveen)
23
San Pedro At Tombstone
24
Proposed Soil Moisture Probes in the San Pedro
near Tombstone and Bobacomari Basins.

• NOAAs ESRL has proposed to place 6 sensors
  within the Bobacomari/San Pedro Tombstone Areas.
• Strengths Existing Soil Moisture studies in
  Walnut Gulch. Bobacomari can be treated as
  headwater.
• Will cluster 3 sensors in one HRAP cell to better
  under stand variability.
• Other three will be placed on a cross section of
  the basin.

25
Continued Study

• Increase the number of calibrated basins.
• Increase the region over which soil moisture
  modeling is computed.
• Work with our customers (WFOs, regional
  scientists and land managers) to better publish
  soil moisture simulations and observations.

26
Questions?
Available at http//www.cbrfc.noaa.gov/present/pr
esent2007.cgi