Flood Management of Douglas County, Kansas

Liz Coffey, Emmy Edie, & Morgan Frehe

Fall 2009
ES351 Introduction to Geospatial Analysis
Dr. James S. Aber, Instructor

Table of Contents
Overview
Introduction
Concerns/Problems
Role of GIS
Conclusion
References

Overview

Fig. 1. Locator map of Douglas County, KS with a red-shaded area for population density. Image courtesy of google.com.

Douglas County is located in the northeastern zone of Kansas. It is 1227 square kilometers of both rural and farm lands. With its population just shy of 115,000, it is the second fastest growing county of the State. The county also has many water bodies such as the Kansas River, Clinton Lake, Lone Star Lake, Douglas County Lake, and many creeks. With that, Douglas County has many flooding problems. Flooding occurs when there has been an extended period of rainfall that causes rivers and streams fill up and spill out into the surrounding areas. Floods are a common problem not only in this county, but state wide. Many projects such as building dams, levees, and reservoirs are important to helping protect from floods.

Fig. 2. Image of damages to homes during the 1951 flood in Lawrence, KS. Image courtesy of Douglas County.

Fig. 3. Bridge over the Kansas River is nearly flooded by the 1951 flood water. Image courtesy of Douglas County.

Some of the most substantial floods were the 1951 which extended to over half of the state severely damaging the Douglas County area. With each flood many thousands of dollars are spent in cleaning up and in some cases rebuilding in the same areas. With the use of an areas history and technology, reducing flood damages can be managable. According to US Geological Survey (USGS),

"Nationwide, the benefits of reducing flood damages or of improving the efficiency of measures designed to prevent damage and loss of life greatly exceed the cost of collecting the data through NSIP."

The National Streamflow Information Program (NSIP) is made up of scientists that collect and analyze data from GIS into useful information. The use of GIS can not only save time and money rebuilding, but also peoples lives.

Introduction

In the discussion of the flood areas in Douglas County, there are two types of causes for the floods that would concern those who hold property in the high and low risk areas. The first cause of a flood occurs when extended amount of rainfall over several days. (NOAA 2009) So with this type you need to be prepared for when the weather is calling for a lot of rainfall over a span of a few days. The second cause of a flood is a swift influx of rainwater to the rivers. Flash floods are characterized as occuring where the flood occurs within six hours of the raining event. Another cause of a flash flood would be a dam or levee failure. (NOAA 2009) In Douglas County it is the Kansas River that rises and floods surrounding areas.

Concerns/Problems of Douglas County Flood Areas

Household concerns include flooding of basements, structural damage of foundation, and loss of property. Other concerns include disease festering from overfilled sewage drains, pesticide leakage into surrounding sediment and waters, and lack of preparation and awareness.

How to prepare for a flood: There are many concerns associated with a flood area. Douglas County is a flood zone because of the Kansas River located in the area. People living in Douglas County must be prepared for flooding and know the hazards involved. First, you should always be prepared for the worst. Keep at least three gallons of water for each person in the household and also a supply of non-perishable foods. Along with these have a radio to keep you updated on the flood and also things such as batteries, extra clothing, and blankets. (Koch 2009) One major concern with floods is pesticides getting into the environment. You should store household cleaners and pesticides out of the way of a flood area of your home, if your basement floods you should be sure to not store these products there. (Koch 2009) You also want to pump out your basement gradually to avoid structural damage. (Health 2009)

Floods can be very dangerous and people need to be aware of the hazards involved. During heavy rain and/or rainfall over a few days make sure to prepare for floods. In Douglas County, KS when the river reaches a flood stage the national weather service will issue a category for the severity of the flood. There are three categories, minor flooding, moderate flooding, and major flooding. (NOAA 2009)These categories are based on the property damage and public threat.

Role of GIS in Flood Management

Data of real-time streamflow is a great resource for the numerical values of discharge and percent of normal (median and mean), stage in feet, and it also gives a value for the flood stage height. When the stage height is increasing to the flood stage height there is an increasing risk of flood. A map found the usgs.gov site can be utilized to find these values.

According to ESRI, floodplain management can only be made effective with the combination of corrective and preventive measures for reducing flood damage. Measures require a great amount of data integrated from different sources including but not limited to: zoning, subdivision, building requirements, and special-purpose floodplain ordinances. There are three specified programs that can be utilized for flood management in any area. The first is a program that was created to compile source information and find ways to work with the derivation of new hydrologic and landscape information. ArcGIS Spatial Analyst: Hydrologic Analysis provides tools to generate a flood forecasting model to identify high and low risk areas for damage.

Fig. 4. Example of data set analysis for San Antonio,Texas in 2004 using ArcGIS Spatial Analysis. Image courtesy of ESRI.

Another tool that can be using for flood management is the Arc Hydro tools that are effective in capturing a 3-dimensional nature of a channel with its physical properties, terrain modeling, riverbed characteristics, and vegetation. Lastly, ArcGIS Tracking Analyst allows time-related data to be analyzed for exploration of trends and phenomena. Historical analysis, "what-if" scenarios, and occuring events like rainfall can also be tracked using the Tracking Analyst.

Conclusion

In Douglas County, floods are the main concern for those living in the greatest population density in Lawrence near the Kansas River. Flooding of the Kansas River has a historical basis with the 1951 flood that incurred a great deal of problems that had to be dealt with. Problems with flooding include but are limited to: property damage, structural damage to homes and businesses, insecticide leakage, lack of awareness, waste management, and loss of life. GIS is essential in flood management because the integration of seperate data sets can be used for future flood forecasts. Douglas County has already mapped areas of high and low risk for flooding using GIS and can now apply this information for its residents.

References

"After the Flood - Health Concerns". Charlotte Fire Department. December 3, 2009 .

Flood: Are You Ready for a Flood or Flash Flood? American Red Cross, National Weather Service, and Federal Emergency Management Agency, Aug. 1998. Web. 29 Nov. 2009. .

"Flood Safety". NOAA, National Weather Service. December 6, 2009 .

"GIS for Water Resources - Flood Management". ESRI. December 8, 2009.

Hester, Gary, comp. Flood Managements of USGS Streamgaging Program. National Hydrologic Warning Council, 19 Oct. 2006. Web. 29 Nov. 2009. .

"Kansas: Definition from Answers.com." Answers.com: Wiki Q&A combined with free online dictionary, thesaurus, and encyclopedias. Answers Corporation. Web. 29 Nov. 2009. .

Koch, Becky. "Pesticide Storage Concerns During a Flood". NDSU. December 5, 2009 .


EB/ES 351 Introduction to Geospatial Analysis.

Emporia State University (2009).