1. Hydrologic Modeling for Watershed Analysis and River Restoration
David Tarboton

2. Learning Objectives Review what you learned yesterday
be familiar with the sources for hydrologic, hydrographic and watershed data useful for watershed analysis
be familiar with hydrologic models and geographic information system tools useful for watershed analysis
be familiar with geomorphologic models for landslides, erosion and calculation of sediment inputs
questions to ask when applying or looking at results from a watershed model

3. The role of watershed processes in runoff and sediment production
Short time scale water balance P ET Q
Gout
Gin S
Retention
How do watershed land use changes impact retention?

4. SCS Curve Numbers to Quantify Retention
CN=100 90 80 70 60 50 40 30 20

5. Grid based terrain flow data model4 5 6 3 7 2 1 8
Eight direction pour point model D8
Grid network 1 4 3 12 2 16 25 6
Drainage Area

6. Key Take Home Message
The GIS grid based terrain flow data model enables the representation of flow processes at and near the earth surface and derivation of a wide variety of information useful for the study of hydrologic processes.

7. What you learned in the exercise
ArcGIS, Bare Essentials
To learn more see
Watershed delineation using TauDEM
To learn more see

8. GIS provides an effective way to organize and synthesize multiple data sources and compute watershed attributes

9. Some Cub River GIS Watershed Analysis Findings
Watershed Area x 106 m2 = 57.4 mi2 (c.f. USGS gauge area 53.7 mi2)
PRISM Mean Annual Precipitation 650 mm = 25.6 in.

10. More Cub River Watershed Analysis Findings
USGS Mean Annual Streamflow based on 12 years of data, : cfs

11. More Cub River Watershed Analysis Findings
StreamStats Regional Regression
Hortness, J. E., and Berenbrock, C, 2001, Estimating Monthly and Annual Streamflow Statistics at Ungaged Sites in Idaho: U.S. Geological Survey Water Resources-Investigations Report , 36 p.
Uncertainty !!

12. We did not get to
Flow distance to streams

13. We did not get to
Raster Calculation
[cubiddist] < 200

14. We did not get to
Land Cover tabulation in buffer zone

15. Roles for Hydrologic Models
Make predictions (of the future)
Quantify and test theories
Evaluate potential outcomes from management alternatives

16. Watershed restoration limitations
Human population growth
Land use
Topography
Climate

17. Realistic Watershed management / alteration / restoration options
Best management practices
Buffer strips
Zoning
Flow (de) regulation

18. Data Sources for Quantification of model inputs and management alternatives
Climate
Geospatial

19. Hydrology Data Layers Streams Drainage Areas Hydrography Channels
Terrain Surfaces
Rainfall
Digital orthophotos

20. National Hydro Data Programs
National Elevation Dataset
(NED)
National Hydrography Dataset
(NHD)
NED-Hydrology
Watershed Boundary Dataset

21.
DEMs
NLCD
NHD
Topographic Maps

23. National Land Cover Dataset
Get the data:

24. USGS National Water Information System
Web access to USGS water
resources data in real time

26. 1:250,000 Scale Soil Information

27. SSURGO (Soil Survey Geographic Database) developed, maintained and available online (soildatamart.nrcs.usda.gov ) by the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS)

34. Regional Watershed Information Systems

35. Specialized data collection e.g. LIDAR
3-D detail of the Tongue river at the WY/Mont border from LIDAR.
Roberto Gutierrez University of Texas at Austin

37. Models for Hydrology and Runoff
Rational Formula Q = C I A
Unit Hydrographs - HECHMS
Continuous Water and Sediment Simulation - EPA BASINS (HSPF and SWAT)
TOPMODEL
DHSVM

39. HEC-HMS Assumptions and Methods
A basin model is constructed by connecting elements comprising
Precipitation Input
Subbasin
Runoff Volume (Infiltration model, e.g. SCS CN, Green-Ampt)
Direct Runoff (Unit Hydrograph)
Baseflow
Reach
Junction
Source
Sink
Reservoir
Diversion

41. HSPF
Comprehensive time series based simulation system designed to accommodate a wide variety of simulation modules

42. Soil and Water Assessment Tool (SWAT)
Continuous time Daily Water Balance Simulation
Developed to predict the impact of land management practices on water, sediment and agricultural chemical yields
Physically based
Includes
Climate - weather generator
Snow
Soil temperature
Canopy storage
Infiltration
Evaporation
Erosion (MUSLE)

43. TOPMODEL
Beven, K., R. Lamb, P. Quinn, R. Romanowicz and J. Freer, (1995), "TOPMODEL," Chapter 18 in Computer Models of Watershed Hydrology, Edited by V. P. Singh, Water Resources Publications, Highlands Ranch, Colorado, p
“TOPMODEL is not a hydrological modeling package. It is rather a set of conceptual tools that can be used to reproduce the hydrological behaviour of catchments in a distributed or semi-distributed way, in particular the dynamics of surface or subsurface contributing areas.”

44. TOPMODEL Key Ideas
Surface saturation and soil moisture deficits based on topography
Slope
Specific Catchment Area
Topographic Convergence
Partial contributing area concept
Saturation from below (Dunne) runoff generation mechanism

45. DHSVM http://www.hydro.washington.edu/Lettenmaier/Models/DHSVM/
Distributed Hydrology-Soil-Vegetation Model
Physically based hydrologic model
Grid-based (DEM)
Two layer canopy for vegetation
Hydrologic effects of vegetation change and forest roads

46. Sediment Production
USLE, MUSLE, RUSLE2, … (
SINMAP (
SHALSTAB (

47. USLE The Universal Soil Loss Equation A = RKLSCP, where,
A = soil loss per unit area (t/ha)
R = Rainfall-Runoff erositivity (Mj*mm/ha*h*yr)
K = Soil erodibility (t*ha*h/ha*Mj*mm)
L = Slope length factor
S = Slope steepness factor
C = Crop (land cover) factor
P = Practice (erosion controls) factor

48. SINMAP - Terrain Stability Mapping
With Bob Pack.

49. Questions to ask about models (What it does)
Are the physics representative of processes in my watershed?
How were the parameters obtained?
Calibration
Out of sample validation (split sample or cross validation)
Reference (lookup based on other attributes)
What are the inputs?
What are the outputs?

50. Questions to ask about models contd.. (Error)
What are the sources of error
Model structural error (differences between physical reality and model equations)
Input data errors
Parameter errors
What is the uncertainty in the inputs?
How does input uncertainty propagate through to the results?
What is the uncertainty in the outputs?

51. Questions to ask about models contd
Questions to ask about models contd.. (Sensitivity, Scale and variability)
How sensitive are the model results to changes or uncertainties in the inputs?
What are the basic model elements
Are the model results sensitive to the size of basic model elements
How does the model account for variability within model elements

52. Are there any questions ?
AREA 1
AREA 2 3 12
This material online: