Utilizing the U.S. Army Corps of Engineers HEC-RAS River Analysis Program in conjunction with AutoCAD Civil 3D, D.L. Howell and Associates can now determine flood levels more quickly and accurately than ever before. HEC-RAS is a computer program that models the hydraulics of water flow through natural rivers and other channels.

When the modeling program is used with a three-dimensional surface in AutoCAD Civil 3D, cross sections and base plan data can be entered in a fraction of the time with much greater accuracy. Another time saving tool is the ability to export the calculated flood water surface right from HEC-RAS back into the site plan for quick and easy display of the flood limits.

With the latest technology associated with flood analysis and hydrologic software, D.L. Howell can very efficiently help a property owner determine whether or not their property or home is located within the floodplain. As it seems that FEMA is constantly updating their maps and more and more property owners are required to pay expensive flood insurance premiums. For this reason it is important for D.L. Howell to stay on pace with the changes and maintain the ability to accurately determine the actual flood elevation where FEMA has not. Many communities located in southeastern Pennsylvania are within areas designated as Zone A. In these Zone A areas, flood delineations are “estimated” by FEMA and can vary by up to as much as 100 feet in some instances from the actual calculated or “modeled” flood boundary. In addition to requiring flood insurance, most municipalities have specific standards for building or developing in an approximate flood area. This is where D.L. Howell can help. Our project experience ranges from an analysis for a single family house to large scale community planning.

Services provided by D.L. Howell are listed below:

• Floodway Modeling
• Flood Insurance Elevation Determinations
• Elevation Certificates
• FEMA Letter of Map Amendments (LOMA)
• Letter of Map Revisions (LOMR)
• Local permitting assistance.

If you would like to discuss your specific project or have any other flood related questions, please contact Andrew DeFonzo or Dave Gibbons at our West Chester Office (610-918-9002).