HMS-PreProA GIS Preprocessor for Extracting Geospatial Dataand Preparing HEC-HMS Hydrologic Models

Cynthia V. CastroFebruary 10, 2016

Manual HEC-HMS Model Input

Complex,Time-consuming,Expensive!

Hydrologic Modeling GIS Preprocessors

CRWR Pre-Pro(Olivera, 1998)

WRAP Hydro(Gopalan, 2003)

AGWA(EPA/USDA, 2002)

HEC-GeoHMS(USACE, 2003)

BASINS(EPA, 2001)

Over 50 User-Steps Required (Errors)Manual Data Processing

HEC Geo-HMS

Preprocessing Project Setup Obtain Data ArcHydro FDR, FAC Basin Processing Batch Points Calculate Slope Hand Select Outlets Longest Flowpath Basin Centroid

CN Grid Precipitation Grid Name Objects Convert Units Select HMS Process TR55 Parameters

Hand-draw points Muskingum-Cunge

User-input parameters Kinematic Wave

User-input parameters

Trending toward “Data as a Service”Providers host large datasets on remote servers and provide standardized methods to search and download specific sets of interest.

Allows data to be gathered automatically as part of a larger workflow.Industry-wide interoperability.

Improved access to geospatial information.

COH GIMS

USGS National Map Viewer 1:24K USGS Grids > 50,000 in U.S.

Accurate runoff estimates depend on theaccuracy of the data provided!

USGS NED DEM (3m, 10m, 30m, LiDAR) NLCD Land Use/Impervious USDA SSURGO Soils (HSG) NHDPlus v2.1 National Hydrography Dataset

Database Development

NHDPlus V2.1 Living Atlas

Geodatabase Output

GIS Preprocessor Toolbox

Database Development

Data Processing

Terrain Preparation

Watershed Delineation

Parameterization

Model Pre-Processing

All data processing options are included in one toolbox window.

HEC-HMSMethodology

Canopy Method SCS Curve Number Green & Ampt SCS Unit Hydrograph Clark Unit Hydrograph Snyder Unit HydrographMuskingum RoutingMuskingum-Cunge Routing

Output: .BASIN File

A text file serving as the HEC-HMS input that summarizes hydrologicelements, basin attributes, and connectivity within the model.

HEC-HMS Model

SCS Curve Number Method

(USDA, 1986)

SCS Curve Number

𝐶𝐶𝐶𝐶 =∑𝐶𝐶𝐶𝐶𝑖𝑖𝐴𝐴𝑖𝑖∑𝐴𝐴𝑖𝑖

1 – Lookup Table2 – Reclassify Land Use3 – Union Soils/LU4 – Individual CN5 – Composite CN

Example:Onion Creek

Onion Creek – FloodPro, austintexas.gov

FEMA Effective Subbasins

> 400 subbasins

Geodata

HUC-12

110 NHDPlusSubwatersheds

HEC GeoHMS

FEMA Effective Model 2008

SCS Curve NumberSnyder Unit HydrographModified Puls + Muskingum-Cunge

HEC GeoHMS

HMS PrePro

SCS Curve NumberSnyder Unit HydrographMuskingum-Cunge

FEMA Effective

Qp (cfs) V (in)

FEMA 101,929 6.88

HEC GeoHMS 99,788 6.77

HMS-PrePro 99,871 6.76

HMS-PreProHEC-GeoHMSFEMA

Conclusion

Data Services may be used for hydrologic modeling. Seamless data Authoritative Limited manual processing

NHDPlus subbasins and reaches provide a national framework consistent with HUC basins.HMS-PrePro may be used to initialize hydrologic

models in NHD format.

Thank you!

Questions?