Application of GIS and Terrain Analysis to Watershed Model Calibration for the CHIA Project

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??