Waller Creek Sub-basin

HMS

Review

• Original project idea scrapped• Difficult to find adequate GIS data

• No measured flow data to validate model results

• Selected new study area

New Area

Area Characteristics

• Located on UT campus at 24th and San Jacinto

• Dr. Barrett has a monitoring point at basin outlet

• Very urban and hydrologically restricted

Goals

• Create terrain model in Arcview

• Process terrain model with HEC-geoHMS

• Create working hydrologic model in HEC-HMS

• Calibrate model and evaluate results with measured rainfall and runoff data

Data

• TIN developed by Esteban Azagra

• One-meter DEM (courtesy of Becky)• Vegetation

• Vegetation Removed

• Dr. Barrett’s rainfall and runoff data at outlet

Interesting Questions

• Which data source is best suited for this application?

• How can we use HEC-geoHMS?

• How can we create a hydrologic model of a restricted basin in a meaningful way?

• How will this model interact with other models created in the area?

Story Begins

• It all started with Esteban Azagra’s TIN• Converted TIN to a grid

• Projected grid from State Plane to UTM

• Overlayed grid onto a DOQQ for position verification

Conversion

• TIN • GRID (DEM)

Projected Grid

• Arc-Info

Projected Grid

• Code

Overlayed Grid onto DOQQ

Story Progresses

• Fun with HEC-geoHMS• Familiar with HEC-geoHMS

• Processed terrain data

• Analyzed final result

Familiar with HEC-geoHMS

Familiar with HEC-geoHMS

HEC-geoHMS In Action!

• Fill Sinks • Flow Direction

HEC-geoHMS In Action!

• Flow Accumulation • Watershed Delineation

HEC-geoHMS In Action!

• End Result: Streams!

• Cool, but bad!

• Why?

• Streams are not behaving

• No way to modify!

Uh – Oh! What now?

Pre-Pro In Action!

• Drew in sewer system • Burned into grid

The Plot Thickens!

• Becky provides one-meter DEM of study area (E00 Files)

• E00 files no longer a mystery to me • Import 71

• Becky solves vegetation problems

Enter LIDAR!

• Vegetated • Vegetation Removed

Processing Both Grids in Pre-pro• LIDAR Flow Direction • TIN Flow Direction

TIN Product

LIDAR Product

Comparison of Watersheds

Comparison of Streams

Creation of HMS Schematic

• TIN GIS Model • TIN Schematic

Creation of HMS Schematic

• LIDAR GIS Model • LIDAR Schematic

The Winner Is:

• LIDAR for HMS • Too cumbersome to do both (out of time)

• LIDAR looks better

• Checked soil types via SSURGO

• Developed curve numbers

• Input hydrologic attributes

• Ran model

Intro to HMS

• 3 Parts

Basin Model

• Chose SCS for loss and transform methods

• Chose no baseflow

• Chose lag method for reach routing

• Parameters by Hand (and Arcview)

Getting Soiled With SSURGO

• All for this?• Soil type is Ur (urban)

• Either C or D

• Land use is urban

• Curve numbers are either 94 (C) or 95 (D)

• I went with 95

Hydrologic Parameters

• Sub-basin attributes• Notice SLOPES!!

• Those darned buildings!!!

Hydrologic Parameters By Hand (and Arcview)

• Reach Attributes

• Chose lag transform• Easy

Meteorologic Model and Control Specifications

• User Specified Hyetograph

• From 0:00 to 23:55 10/18/99

• 5 minute increments

RESULTS!!!

• After all of this hard work: I am ready to reap what I have sowed

Comparison to measured data:

Looks good …

• But I’m off by a factor of 10• Units problem?

• Variability in rainfall?

• Another problem?

• ???

I Would Like To:

• Calibrate this model (determine problem)

• Try to use HEC-geoHMS in combination with Pre-pro (burn sewers, process with geoHMS)

• Figure out how to make Pre-pro transfer hydrologic attributes

• Study how this model fits into models already completed

Questions?