application of gis and terrain analysis to watershed model calibration for the chia project
DESCRIPTION
Application of GIS and Terrain Analysis to Watershed Model Calibration for the CHIA Project. Sam Lamont Robert Eli Jerald Fletcher. Background. CHIA: Cumulative Hydrologic Impact Assessment of a mine site Required of WVDEP , for each proposed mine permit - PowerPoint PPT PresentationTRANSCRIPT
Application of GIS and Terrain Application of GIS and Terrain Analysis to Watershed Model Analysis to Watershed Model
CalibrationCalibrationfor the CHIA Projectfor the CHIA Project
Sam Lamont
Robert Eli
Jerald Fletcher
BackgroundBackground
CHIA: Cumulative Hydrologic CHIA: Cumulative Hydrologic Impact Assessment of a mine site Impact Assessment of a mine site
Required of WVDEP , for each Required of WVDEP , for each proposed mine permitproposed mine permit
Surface and groundwater quality and Surface and groundwater quality and quantityquantity
WVU’s RoleWVU’s Role
Ultimate goal: Graphical tool to simulate Ultimate goal: Graphical tool to simulate pre- and post-mining conditionspre- and post-mining conditions
Water quantity: Calibrate watershed Water quantity: Calibrate watershed model (HSPF) to 235 basins in WVmodel (HSPF) to 235 basins in WV
235 Study Watersheds and Their Outlets235 Study Watersheds and Their Outlets
BASINS-GIS FrameworkBASINS-GIS Framework• ArcView based environment for display and analysis of watershed features
• Develops input files for HSPF
- watershed file (landuse, slope, area)
- stream network
- reach attributes
- point sources
• This project: WCMS
HSPF: Hydrologic Systems HSPF: Hydrologic Systems Program - FortranProgram - Fortran
Continuous
Calculates water balance for each time step
R = P – ET – IG – S
where: R = Runoff
P = Precipitation
ET = Evapotranspiration
IG = Deep/Inactive Groundwater
S = Change in soil storage
Surface and sub-surface hydrology
Inputs = Precip, PET, Temp
Output = Simulated flow
Modeled Precipitation GridModeled Precipitation Grid
- Hourly Precip
- 1948 – 2002
- 5 km resolution
How HSPF Represents a WatershedHow HSPF Represents a Watershed
Example:
- 5 Sub-watersheds
- 5 Stream reaches (Storage-Outflow routing)
- Land use typesForest (Steep,Moderate, Mild)
Shrub-land
Pasture/Grassland
Urban
MineBarrenRow CropWetland Surface Water
Outlet point
Watershed boundary
Flow Direction
Stream reach
Legend
WV_Slope
<VALUE>
0 - 15
15 - 25
25+
wvstate_83
WV_Slope<VALUE>
0 - 15
15 - 25
25+
Percent Slope DistributionPercent Slope Distribution
5 Calibration Watersheds5 Calibration Watersheds
Model CalibrationModel Calibration
Trial and error:Trial and error:
1. Run Model1. Run Model
2. Compare output2. Compare output
3. Adjust parameters3. Adjust parameters
4. Repeat4. Repeat
Other software assists this processOther software assists this process
HSPEXP: Calculates error statistics, provides advice, plotsHSPEXP: Calculates error statistics, provides advice, plots
Typical Results: Tygart Valley River at ElkinsTypical Results: Tygart Valley River at Elkins
Further Proposed Terrain Analysis Further Proposed Terrain Analysis for Calibration Improvementfor Calibration Improvement
• Hoes does watershed Hoes does watershed shape and structure relate shape and structure relate to hydrology?to hydrology?
• Searching for an index Searching for an index defining hydrologic defining hydrologic characteristics.characteristics.
Some examples…
Topographic IndexTopographic Index
Beven and Kirkby, Beven and Kirkby, 19791979
TI = ln(a/tanB)TI = ln(a/tanB)
a = areaa = area
B = slopeB = slope
(relative wetness)(relative wetness)
Example: Abes Run, Canaan Valley
Rugosity-Surface Area/Planar AreaRugosity-Surface Area/Planar Area
Drainable VolumeDrainable VolumePercent Drainable Volume vs. Percent Height
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Percent Height
Per
cen
t V
olu
me
Twelvepole Creek Watershed
Tygart Valley at Elkins
Big Sandy
Buffalo
Clearfork
- Volume of watershed above a particular elevation
ConclusionConclusion
Future steps:Future steps:
- Fine-tune calibration: - Fine-tune calibration: Continue searching for patternsContinue searching for patterns
- Validate model- Validate model
- Mine site modeling- Mine site modeling
- Link with WCMS- Link with WCMS
QuestionsQuestions??