A Flood Alert System for Columbus, Indiana

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In June 2008, heavy rainfall occurred in the upstream reaches of Haw Creek, a small stream that flows through the center of Columbus, Ind. A sudden flash flood occurred through the middle of Columbus which took the town by surprise since the rain was upstream. Many homes and more than 70 businesses were damaged in Columbus, including $125 million in damage to the Columbus Regional Hospital and $100 million in damage to a diesel engine manufacturer research and development center. Unfortunately, during the 2008 flooding in Columbus, there were no streamgages on Haw Creek, nor were than NWS flood forecast points. USGS streamgages and collocated National Weather Service (NWS) flood forecast points can provide early warning of impending flooding. 

We will be developing two rainfall-runoff models in cooperation with the NWS for flood forecasting on Haw Creek. The existing Columbus flood response plan will be updated to integrate the new models and related products.

Flooding causes more deaths and damage than any other weather-related phenomena, and three-quarters of all federal disaster declarations are due, at least in part, to flooding.

Flooding in Columbus, Indiana, June 2008

Flooding in Columbus, IN, June 2008

Flood damages in Indiana are increasing:

  • From 1955 to 1989, total recorded flood damages were estimated at $419 million (in today’s dollars);
  • From 1990 to 2003, total recorded flood damages were estimated at $701 million.
  • From January 2008 through March 2009, six severe flood events resulted in the loss of life and property damage in the hundreds of millions of dollars.

One Indiana community in particular, Columbus, suffered severe flood impacts in June 2008. Haw Creek is a small stream which runs through the center of Columbus.  Heavy rainfall occurred in the upstream reaches of the Haw Creek watershed which caused a severe flash flood as it moved downstream through Columbus. Many homes and more than 70 businesses were damaged in Columbus, including $125 million in damage to the Columbus Regional Hospital and $100 million in damage to a diesel engine manufacturer research and development center. We are working cooperatively with the National Weather Service to develop a flood alert system for Columbus, Indiana, including two rainfall-runoff models; updates to the current Columbus Flood Response Plan; and the ability for local officials to detect, track, and respond to future flood events.

Unfortunately, during the 2008 flooding in Columbus, there were no streamgages on Haw Creek, nor were than NWS flood forecast points to help alert the town. USGS streamgages and collocated National Weather Service (NWS) flood forecast points can provide early warning of impending flooding. Emergency management officials can

  • monitor the real-time data from a USGS streamgage, available through the Web, to detect the start of floods, and 
  • monitor the NWS flood forecast at that streamgage – flood levels are forecast up to five days in the future.

We installed two streamgages in 2010 on Haw Creek with real-time data telemetry:

June 2008 flooding in Columbus, IN

Flooding in Columbus, IN, June 2008

To further assist Columbus, the Indiana Office of Community and Rural Affairs (OCRA) funded an Indiana Silver Jackets (ISJ) project to a develop a flood inundation map library for selected sites across Indiana, including for Haw Creek in Columbus. The library provides a series of inundation maps, accessible through the Web, that show the depth and extent of flooding for different water recorded at the Haw Creek near Clifford streamgage. The City of Columbus also contracted with Christopher Burke Engineering LTD. to develop a flood response plan for the community – this plan uses the streamgage data and other information to provide a comprehensive plan of actions to safeguard life and property for different flood levels.

How We Are Helping

We are working cooperatively with the NWS to develop two rainfall-runoff models:

The NWS model will be used in a “site specific application” for the agency’s Advanced Hydrologic Prediction Service (AHPS).

  • NWS will be able forecast floods for the Haw Creek at Clifford streamgage site through AHPS Web services.
  • Haw Creek at Clifford streamgage site will be designated as a NWS flood forecast point. 

Our model will be an independent model developed using a rainfall runoff model called TOPMODEL for a local application that can be used for

  • validation of the NWS model,
  • running event scenarios for both response and future mitigation planning, and
  • as a redundant system to the NWS site specific model prior to or during floods.

Data and information from both models will be provided to the city of Columbus for updating the current City of Columbus Flood Response Plan. These models will form the base of the flood alert system.

The flood alert system will have the following functions:

  1. Event detection: Local officials are alerted to the potential for heavy rainfall 3 to 5 days out using forecast precipitation products from the NWS Hydrometeorological Prediction Center.
  2. Event monitoring: Local officials can monitor precipitation and AHPS flood forecasts as they are refined (3–5 day forecasts have a high level of uncertainty).
  3. Response: Based on NWS observed rainfall, Haw Creek stages from the streamgages, and the NWS flood forecast, local officials will be able to respond to flooding using their flood response plan. Observed and predicted flood stages at the Haw Creek at Clifford streamgage/flood forecast points can be used in conjunction with the Haw Creek flood inundation map library to estimate the current and forecast extent and depth of flooding in the community. Also, as part of response, officials will be able to use the USGS watershed response model to run various scenarios.
  4. Recovery: The system will archive actual rainfall, stream stages, and other pertinent information so that local officials can assess the magnitude of the flooding and use that information for post flood assessments. Officials will also be able to assess the effectiveness of the system and flood response plan and recommend adjustments to system components.
  5. Planning: Community planners will be able to run various storm scenarios to assess the flooding potential in the community – this can be used to make future development more resilient to flooding.

Model and Application Development

We are developing a calibrated watershed response model, using a version of a rainfall runoff model TOPMODEL, for the watershed of Haw Creek upstream of the Haw Creek at Clifford streamgage as well as an associated application for local officials.  

  • Hydrologic response is simulated using a combination of physical characteristics (geology, soils, topography, and land-cover) as sampled from a GIS database.
  • Data inputs for the Haw Creek watershed will include a digital elevation model derived from LiDAR, soils data, and land-cover/land-use data.
  • Output from the model will be simulated streamflow hydrographs (graphs of streamflow versus time) for various landscape and climatic conditions.
  • Stages for corresponding streamflows using the Haw Creek at Clifford rating (relation between stage and streamflow developed for the streamgage) will be computed.
  • A stage hydrograph will be provided for each model generated streamflow hydrograph.
  • Users will then be able to access the flood inundation maps corresponding to various stages from the Haw Creek flood inundation map library.
  • Users will be able to simulate the extent and depth of flooding through Columbus, from Haw Creek for various storm scenarios.
  • NWS predicted precipitation and observed radar-estimated precipitation and output streamflow and stage data will also be available in the application.

How does the City of Columbus use the Resources Being Developed?

A workshop will be developed to train local officials, interested Silver Jackets partners, and other stakeholders on the use of the flood alert system resources. Workshop topics will include:

  • NWS flood watch, warning, and forecast products and resources
  • USGS streamgage data, WaterAlert, and other flood-related resources
  • Use of the NWS Haw Creek at Clifford flood forecast point
  • Use of the USGS WATER application
  • The Columbus flood response plan
  • “End-to-end” flood monitoring – a summary of putting all of the resources together