Hydrologic Model Integration

Francisco Olivera, Ph.D., P.E. Texas A&M University

Department of Civil Engineering

Model Integration

Sharing of information between models is necessary to capture the complexity of natural hydrologic processes.

This sharing of information between models in a systematic fashion is called here model integration.

Model Integration

Connection on a two-model basis.Depends on the already connected

models.

Model Integration

Connection on a hub basis.Independent of the already

connected models

HUB

Arc Hydro

Arc Hydro can be used as the hub for connecting hydrologic models.

What it is and what it is not …

Arc Hydro is a standard data model for spatial and temporal hydrologic data.

A data model is a template for organizing data, so that it can be found and retrieved easily.

Arc Hydro is a geodatabase, that is, a relational database that contains geographic information.

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River network

Watersheds Waterbodies

Points

PrePro2002

PrePro2002 is an ArcGIS pre-processor for the HEC Hydrologic Modeling System (HMS) developed by Texas A&M University – Civil Engineering and Dodson and Associates, Inc.

HEC-HMS “is a new generation software for precipitation-runoff simulation that supersedes the HEC-1 Flood Hydrograph Package.” (HEC-HMS User’s Manual)

HUB

HEC-HMS

Arc Hydro

HUB

PrePro2002

PrePro2002 uses the ArcGIS hydrologic functions to analyze the terrain.

67 56 49

53 44 37

58 55 22

PrePro2002

Flow direction codes

1

248

16

32 64 128

The eight-direction pour point algorithm (D-8) assigns a flow direction code to each cell, based on the steepest downhill slope as defined by the DEM.

67 56 49

53 44 37

58 55 22

1 1

60.1522244

00.7

13744

71

56

445369

74

78 72 69

4768

58 55

21

31

67

58

49 46

37 38

64 22

61 16

PrePro2002

DEM

22

2 2 2

2

4 4

4 4

1 1 2 4 8

128

128 1 2 4

128 1 41

128

Flow direction grid Flow network

0 0 0 0 0

0 1 1 2 1

0

0

0 0 0

3 8 5 2

1 1 20 0

1 24

Flow accumulation grid Flow accumulation(> 2 cells)

Watersheds

PrePro2002

Flow direction grid Flow accumulation grid

PrePro2002

Reaches Outlets

PrePro2002

Reaches and watersheds HMS basin file

PrePro2003

PrePro2003 will store the hydrologic elements in seven feature classes: HMSSubbasin HMSReach HMSJunction HMSSource HMSReservoir HMSDiversion HMSSink

PrePro2003

PrePro2003 will calculate the parameters of the hydrologic elements and store them as attributes of the seven feature classes.

PrePro2003

PrePro2003 will store the hydrologic time series in one object class: DSSTimeSeries

PrePro2003

Using XML files, PrePro2003 will prepare a HEC-HMS input file.

Conclusions

Using an standard data model, it is possible to analyze complex hydrologic processes that require the use of multiple models and participation of multiple modeling teams.

The Future