This document discusses the history and recent advances in hydrologic modeling. It begins with definitions of hydrology and applications of hydrologic models such as water resources planning. It then discusses the historical development of early component models in the 1900s and the creation of integrated watershed models starting in the 1960s. Recent advances include the use of remote sensing, GIS, and handling spatial and temporal variability. The future outlook emphasizes increasing model complexity through linking with other domains and improving reliability.

1. a)(ft G
YDROLOGIC
MODELING
• INTRODUCTION
• HISTORY
• RECENT ADVANCES
• FUTURE OUTLOOK

2. INTRODUCTION
• DEFINITION OF HYDROLOGY
- What happens to the ram?
Occurrence, Movement, Distribution, and
Storage of Water Quantity and Quality
- Spatial, Temporal, and Frequency Domains
(or Characteristics)
- Quality of Water-Physical, Chemical and
Biological
- Spatial Scale-Watershed, Regional (Basin),
Continental, and Global
- Dynamic Interaction between Atmosphere,
Pedosphere, Lithosphere, and Hydrosphere-
Controlling Influences on Hydrology

3. APLICATION OF
HYDROLOGIC MODELS
• PLANNING, DESIGN,
DEVELOPMENT, OPERATION, AND
MANAGEMENT OF WATER
RESOURCES PROJECTS
• WATERSHED MANAGEMENT
• ENVIRONMENTAL PROTECTION
AND MANAGEMENT
• CLIMATE CHANGE

4. APPLICATION OF
HYDROLOGIC MODELS
0
SPECIFIC EXAMPLES
- Flood Protection Projects, Flood Warning
Systems, Reservoir Release Planning, Flood
Plain Management, etc.
Rehabilitation of Aging Dams
Water Supply Forecasting
- Irrigation Water Management
- Wetland Restoration
- Stream Restoration
- Water Table Management
- Drainage Systems Design
- Soil Conservation Practices
- Habitat Modeling
- Hydropower Development
- Consumptive Use and Water Allocation

5. HISTORICAL
PERSPECTIVE
0
THE BEGINNING YEARS:
DEVELOPMENT OF COMPONENT
MODELS
o Surface Runoff Modeling
• Rational Method (Mulvany, 1850;
Imbeau, 1892)
• Unit Hydrograph Method (Sherman,
1932)
• Overland Flow Analysis (Keulegan, 1944;
Izzard, 1944)
• Unit Hydrograph Theory (Nash, 1957;
Dooge, 1959)
o Subsurface Flow Modeling
Subsurface Flow Mechanism
(Lowdermilk, 1934; Hursh, 1936; Hursh
and Brater, 1944; Hoover and Hursh,
1944; Hursh, 1944; Roessel, 1950;
Hewlett, 1961; Nielsen et al., 1959;
Remson, et al., 1960)

6. HISTORICAL PERSPECTIVE
• Determination of Storm Runoff
Amount
SCS-CN Method (1956)
• Theory of Infiltration
Green-Ampt Model (1911)
Kostiakov Model (1932)
Horton Model (1933)
• Theory of Evaporation
Energy Method (Richardson,
1931; Cummings, 1935)
Combination Method (Penman,
1948)

7. HISTORICAL PERSPECTIVE
• Determination of Abstractions
- Interception (Horton, 1919)
- Detention and Depression Storage
(SCS9 1956)
o Base Flow
Darcy Equation (1854)
Hydraulic Conductivity Relation
(Fair and Hatch, 1933)
Well Response to Pumping (Theis,
1935)
Correlation between Ground Water
and Precipitation (Jacob, 1943, 1944)

8. HISTORICAL
PERSPECTIVE
o Reservoir Routing
Puis Method (USACOE, 1928)
Modified Puis Method (USBR, 1949)
o Channel Routing
Muskingum Method (McCarthy,
1934-35)
Modified Puis Method (USBR, 1949)

9. WATERSHED MODELS
• MODELS OF HYDROLOGIC CYCLE
• STANFORD WATERSHED MODEL (NOW
HSPF) (Crawford and Linsley, 1966)
• EXAMPLES OF MODELS
- HSPF-IV (Bicknell et al., 1993)
- USDA-HL Model (Holtan et al.,
1974)
- PRMS (Leavesley et al., 1983)
- NWS-RFS (Burnash et al., 1973)
- SSARR (Rockwood, 1982)
- SWMM (Metalf and Eddy et al.,
1971)
- HEC-HMS (U. S. Army Corps of
Engineers, 1999)

10. WATERSHED MODELS
KINEROS (Woolhiser et al, 1990)
- ANSWERS (Beasley et al., 1977)
- CREAMS (USDA, 1980)
- EPIC (Williams, 1995)
SWRRB (Williams, 1995)
SPUR (Carison et al., 1995)
AGNPS (Young et al., 1995)
- WATFLOOD (Kouwen et al., 1993)
- UBC (Quick, 1995)
- SHE (Abbott et al., 1986)
- TOPMODEL (Beven, 1995)
- IHDM (Calver and Wood, 1995)
- SHETRAN (Ewen et al., 2000)
MI

11. WATERSHED MODELS
- WBNM (Boyd et al., 1979)
- RORB (Laurenson and Mein, 1995)
- THALES (Grayson et al., 1995)
LASCAM (Sivapalan et al., 1996)
- Tank Model (Sugawara, 1975)
- Xinanjiang Model (Zhao et al., 1980)
- HBV Model (Bergstrom, 1976)
- ARNO Model (Todini, 1988)
- TOPIKAPI Model (Todini, 1995)
- HYDROTEL (Fortin et al., 2001)

12. CLASSIFICATION OF
WATERSHED MODELS
0
CRITERIA FOR CLASSIFICATION
- Process Description
- Dynamics and Simplification
Time Scale
- Space Scale
- Method of Solution
- Land Use
- Model Use
- Model Complexity

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15. MODEL CONSTRUCTION
• MODEL ARCHITECTURE AND
STRUCTURE
• WATERSHED REPRESENTATION
• HYDROLOGIC PROCESS
- Precipitation
- Storage Abstractions
- Evaporation and Evapotranspiration
- Infiltration
Soil Moisture Accounting
- Runoff Production
Snowmelt Runoff
- Surface Runoff Routing
- Channel Flow Routing
- Interflow
- Groundwater Flow
- Stream-Aquifer Interaction
- Water Quality

16. MODEL CONSTRUCTION
• MODEL CALIBRATION
• GOODNESS-.OF-TEST
• MODEL VALIDATION
• MODEL ERROR ANALYSIS
• MODEL RELIABILITY

17. RECENT ADVANCES
o
HYDROLOGIC PATA NEEDS
- Hydrometeorologic
- Topographic
- Geomorphologic
- Pedologic
- Land Use
Lithologic
Hydraulic
HYDROLOGIC PATA ACQUISITION
- Remote Sensing
- Satellite Technology
Radar Technology
- Digital Terrain and Elevation Modeis
- Chemical Tracers
o
PATA PROCESSING AND MANAGEMENT
- Geographical Information Systems (GIS)
- Pata Base Management Systems (DBMS)

18. RAINFALL VARIABILITY
• STORM MOVEMENT
• SPATIAL VARIABILITY
• TEMPORAL VARIABILITY
• RAINFALL FIELD
DESCRIPTION
• RAINFALL FORECASTING

19. VARIABILITY IN
WATERSHED
CHARACTERISTICS
0
SPATIAL VARIABILITY OF
HYDRAULIC ROUGHNESS
- Effect 011 Runoff Dynamics and Hydrograph
- Formation of Shocks
SPATIAL VARIABILITY OF
INFILTRATION
- Hydraulic Conductivity
Steady Infiltration
- Mean Infiltration
Effect on Runoff Hydrograph

20. SCALING AND
VARIABILITY
• SPATIAL SCALING
- Spatial Heterogeneity in Watershed
Characteristics
- Spatial Variability in Processes
• PHYSICAL SPATIAL SIZE
- Representative Elementary Area
- Hydrologic Response Units
- Computational Grid Size
• TEMPORAL SCALING
- Time Interval of Observations
- Computational Grid Size
- Temporal Variability of Processes

21. LIN NG HYDROLOGIC
MODELS
• GEOCHEMISTRY
• ENVIRONMENTAL BIOLOGY
• METEOROLOGY
• CLIMATOLOGY
• OCEANOGRAPHY
• SOCIAL SCIENCES
• ECONOMICS
• DECISION MAKING

22. MODEL CALIBRATION
9
PARAMETER ESTIMATION
ALGORITHM
Obj ective Function
Optimization Algorithm
- Termination Criteria
- Calibration Data
• HANDLING DATA ERRORS
• DETERMINATION OF DATA
NEEDS-QUANTITY AND
INFORMATION-RICHNESS
REPRESENTATION OF
UNCERTAINTY OF CALIBRATED
MODEL
• ARTIFICIAL NEURAL NETWORKS

23. FUTURE OUTLOOK
• INCREASING SOCIETAL DEMAND
FOR MODELS
• INCREASING EMPHASIS ON
LINKING MODELS TO
ENVIRONMENTAL AND ECO-
SYSTEMS
• EMPHASIS ON USER-
FRIENDLINE SS
• INC ORPORATION OF
INFORMATION TECHNOLOGy,
COMPUTER-BASED DESIGN,
ARTIFICIAL INTELLIGENCE, AND
SPACE TECHNOLOGY
• MODEL UNCERTAINTY AND
RELIABILITY
• MODEL COMPETITIVENESS