Interface data models Model 1 Model 2 Model 3 GIS Geo Database Arc Hydro data model Geographically Integrated Hydrologic Modeling Systems

Arc Hydro — Hydrography

Arc Hydro — Hydrology

Geographic Data Model Conceptual Model – a set of concepts that describe a subject and allow reasoning about it Mathematical Model – a conceptual model expressed in symbols and equations Data Model – a conceptual model expressed in a data structure (Logical data model, physical data model) Geographic Data Model – a data model expressed in a GIS database

Data Model based on Inventory of data layers

Data Model Based on Behavior “Follow a drop of water from where it falls on the land, to the stream, and all the way to the ocean.” R.M. Hirsch, USGS

Flow Time Time Series HydrographyHydro Network Channel System Drainage System Arc Hydro Components

Streams WatershedsWaterbody Hydro Points Arc Hydro Framework Input Data

Arc Hydro Framework Data Model

Hydro Network (NHD) Basins Waterbody (NHD) Arc Hydro Framework For South Florida Hydro Points

Nexrad Radar Rainfall Map

Extended Arc Hydro Framework for South Florida Arc Hydro Framework Extended Arc Hydro Regional Simulation Model Operations Decision Support System Flood Modeling and Management HydroPeriod Analysis Framework for South Florida

1. Define the Data Themes in the Core Model Hydrographic lines Water bodies Drainage areas Structures Gages + …….. Who will produce and verify these data? Will National Hydrography Dataset be used?

2. Define the ODSS GIS Framework Select the ODSS waterbodies and structures from the core GIS framework Integrate water control units in GIS Define drainage area for each WCU Build interface data model for ODSS Build tools for 2-way linkage between ArcGIS and ODSS

Extended Arc Hydro Framework Water body Canal Segment LakeMarsh Tidal HydroEdge HydroJunction Uncontrolled Junction Controlled Junction Structure WCU Schematic Node 1..* Arc Hydro UML for ODSS Subtypes 1 WCU Schematic Link Hydro network Water Control Network MonitoringPoint Basin 1..* 1

3. Define the Flood Modeling Framework Define drainage areas, channels and control structures to be included Define flood simulation model(s) to be used Design ArcGIS interface data model, if necessary Populate models with GIS data (Watershed analyst) Build tools for 2-way linkage between ArcGIS and Flood Models, if necessary

4. Define the RSM GIS Framework Generalize GIS data needed for RSM (linear referencing and event themes) Generate triangular mesh Represent canal segments and pseudocells in GIS Define ArcGIS interface data model for RSM Build tools for 2-way linkage between ArcGIS and RSM

5. Define GIS Functionality for Hydroperiod Define conceptual framework Convert to mathematical form Define data structures needed Build tools to execute model Check against observed points to verify analysis Train the District staff!

6. Build the District Arc Hydro Framework Build the HydroNetwork Connect the drainage areas Connect the structures and monitoring points Integrate other themes (e.g. District RSM mesh?)

7. Define the Water Inputs Connect to the Nexrad data Connect to dbHydro for gage information Satellite information? Climate information? Water quality?

8. Build Information Flows Among Applications Arc Hydro Framework Extended Arc Hydro Regional Simulation Model Operations Decision Support System Flood Modeling and Management HydroPeriod Analysis Framework for South Florida

Regional Storm Water Modeling Program and Master Plan for San Antonio

Regional Watershed Modeling Master Plan Goals Develop new or incorporate existing hydrology, hydraulic and water quality models (“Bring the models together”) Provide GIS-based interfaces for models Provide for maintenance of models and geospatial data Develop standards for modeling and geospatial data Regional Watershed Modeling System to assist in: –flood mitigation planning –capital project prioritization

Modeling System Rainfall Data: Rain gages Nexrad Calibration Data: Flows Water Quality Geospatial Data: City, County SARA, other Floodplain Management Integrated Regional Water Resources planning Capital Improvement Planning Flood Forecasting Water quality planning San Antonio Regional Watershed Modeling System

Arc Hydro and HEC-HMS Arc Hydro Schematic Network HEC-HMS Hydrologic Model Calculates Flows

Arc Hydro and HEC-RAS Arc Hydro Channel Cross Sections HEC-RAS Hydraulic Model Calculates Water Surface Elevations

Flow Change Points Models communicate with one another through Arc Hydro at designated points

Nexrad Map to Flood Map in Model Builder FLO ODP LAIN MAP Flood map as output Nexrad map as input Model for flood flow Model for flood depth HMS

Hydrologic Modeling within ArcGIS Reverse engineer the parameter values from calibrated hydrologic simulation models into the interface data model LibHydro – a library of hydrologic processing functions callable as a dll Schematic network processor to execute functions in the right order

Schematic Network Standard Arc Hydro data structure –Schematic Links –Schematic Nodes Type 1 Nodes and Links for Watersheds Type 2 Nodes and Links for Streams Type 3 for …..

Schematic Network Processes Node processes –Rainfall-runoff and pollutant loads on watersheds –Summing flows or loads on streams –Water quality in water bodies Link processes –Routing flows in streams –Pollutant losses in streams

LibHydro A Fortran subroutine library of hydrologic processes developed from HEC-1 Packaged in LibHydro.DLL for operation under Visual Basic Transforms input time series to output time series More details on GISHydro 2003 CD

Excess Calculation Initial Loss and Constant Loss Rate function Pick up a watershed HydroID = 2346 ImperviousAreaRatio = InitialLoss = 1.6 (mm) ConstantLossRate = 0.38 (mm) Simulation Period: 7/21/97 – 7/23/97 (3 days) Time Interval: 15 minutes Time step: 4 * 24(hour) * 3(days) = 288

Runoff Calculation Snyder Unit Hydrograph Pick up a watershed Watershed area: (km 2 ) SnyderCp: 0.8 SnyderTp: 5.58 (hr) Simulation Period: 7/21/97 – 7/23/97 (3 days) Time Interval: 15 minutes

Outflow Calculation Add Baseflow module Outflow = runoff + baseflow Recession Ratio = 0.95, Threshold value = 2 (m 3 /s)

Looping Through the Schematic Network Get Upstream Features Get Upstream Values Process Upstream Values Process Value to Pass Update Value Collection Topology Collection Value Collection Receive Process HydroID Upstream HydroIDs HydroIDsValues Feature, Values Feature, Value Processed Value Pass Process Processed Value HydroID, New Value See GISHydro2003 CD for details

Schematic Network Process Implementation Geodatabase DLL (MBSchematic.dll) Script (ProcSchematic.vbs) ArcToolbox Script Tool (ProcessSchematic) Process DLL 1Process DLL n GIS Script and DLLs

Strengths of ArcGIS for Modeling Integration with the COM environment, use of Visual Basic, and accessibility of models through dlls is great step forward Network topology a big help for water resources networks Geodatabase design process is important for modeling system architecture Model Builder is great for handling work flow sequences

Limitations of ArcGIS for Modeling No data model and tools for time series in core software Graph plotting is inadequate for displaying time series Relationships are critical in geodatabase design but can’t be created in ArcView – separate toolkits for ArcInfo and ArcView implementation of modeling systems? No scheme for scenario management

Overall Assessment Geographic framework: solid Model connections: good architecture, needs development Time series: being improved with current research Hydrologic Information System