Down on the Bayou (Part 1)
Regional developers are commonly challenged with developing low-lying land within the floodplain. Unlike stormwater regulations, which mostly defer to Harris County Flood Control Standards (HCFD), floodplain development regulations are unique to all 64 jurisdictions within Harris County alone. These regulations have been adopted by FEMA, and to participate within the National Flood Insurance Program (NFIP) these jurisdictions must have similar regulations, but not always similar interpretations. It can be confusing.
The primary purpose of floodplain regulation is to protect human life. Ancillary to this is the minimization for rescue and relief efforts associated with flooding, prolonged business interruptions, and damage caused by flooding to public and franchise utilities and roadways. To facilitate this intent, communities must restrict land uses that increase risk during floods by controlling the alteration of natural floodplains, stream channels and natural protective barriers that accommodate floodwaters. Responsible jurisdictions will review plans for all projects within the 100-year floodplain, regulating for fill, grading and dredging while preventing construction of flood barriers that divert floodwaters to other lands.
Some jurisdictions have decided to hold new development to a higher standard. This allows every member of that community to receive a discount on flood insurance. For example, Houston has achieved a CRS rating of 5, which gives residents a 25% discount on non- preferred risk flood insurance policies. Harris County has achieved a rating of 7, equaling a 15% discount.Banks require homes purchased in the flood zone to have flood insurance to qualify for a federally insured mortgage. Communities must participate in the NFIP in order to allow residents to purchase flood insurance. Thus, a well written and clearly defined floodplain regulation is required of the community. Not all of them are.
When you discover that you are in a contract to purchase a property within the floodplain, knowing the right civil engineers, land surveyors, and appraisers might be the difference in profit versus loss. Feasibility and risk assessments, defining maximum developable limits and understanding the value impact of floodplain regulation compliance are all actions to be applied prior to acquisition. The right land experts will help you develop an economical building plan that is compatible with floodplain regulation by raising habitable structures, minimizing fill in the floodplain portions of the project, locating items that are high-risk during a flooding event up, while locating items that are low-risk down. As every site is unique, remember that the most important thing an expert can do is to design something uniquely suited for your specific site.
To help understand the value of project implementation or no implementation at all due to increased flood risk, HCFD is working with FEMA to update flood maps to reflect new precipitation data as published by NOAA. To learn more about floodplain development visit https://www.hcfcd.org, or look for my next article on practical construction techniques in the floodplain in Down on the Bayou part 2. Dwayne Culp, PhD., P.E., CFM
Dr. Culp is the most senior hydrologist at Tetra Land Services and has three decades of civil engineering experience. His Ph.D. scholarship studied the effectiveness of structural BMP for the control of storm water pollution in Harris County while performing water quality monitoring and modeling upon selected ponds for the county. Dr. Culp also co-authored the City of Houston stormwater quality management plan. He is one of Texas’s original Certified Floodplain Managers. Recently, Dr. Culp and his staff have developed a series of drainage studies for Industrial and Oil Majors along the Texas Gulf Coast. Dr. Culp is married with two children, and lives on his farm in Southwest Houston.