Every Builder’s Concern
Harris County is in the process of issuing new flood maps based on Atlas 14 rainfall amounts showing an increase in rainfall by 20%. The net result is that for most buildings in the Houston area floodplains, the water surface elevations will be increasing. Every building owner needs to review the preliminary maps to determine how they impact the properties they own.
Developers may review the preliminary proposed elevations before they become effective by contacting the esteemed Mr. Todd Ward (346-286-4000) at Harris County Flood Control District. These preliminary proposed elevations can be used now to allow the development to raise their finished floor elevations and fill portions of their land before the new flood elevations require mitigation of this fill. Tetra Land Services has one client within the Buffalo Bayou Watershed that is doing floodplain fill to raise the property. Had they waited until the new maps were published, they would have had to mitigate for 6 more feet of fill than they do today.
For properties within the proposed floodplain change, a survey will determine if the buildings and surrounding land are elevated enough to be protected from the new floodplain elevation. If you are higher than the new floodplain elevations, and are shown as within the floodplain, you can protest the map elevations during the review period. FEMA cannot charge money for the review of protests, so you may save significant amounts of capital by not waiting until the maps are published and having to implement a LOMR or LOMR-F.Properties that are within the preliminary new flood plain may have a short window of time in which fill may be done without the necessary offsetting floodplain mitigation. An engineer can help you understand this process before the proposed maps are adopted. The window to take advantage of this opportunity will be approximately one year, during which a properly engineered site grading plan must be prepared, reviewed, approved, and construction commenced. For commercial buildings in the new floodplain, the review period may also be the time to implement floodproofing methodologies as described in my previous article, “Down on the Bayou Part 3.” The mitigation cost of a permanent berm system around a structure could be significantly reduced by implementing a plan in advance of the adoption of the new maps.
For new home or commercial building buyers, reviewing proposed elevations or preliminary maps can save on floodplain insurance over the mortgage term. Existing homeowners in the new floodplain zone should buy insurance now, before the maps are published, to benefit from grandfathering and lower costs. Remember that all federally backed mortgages require flood insurance for homes within the 1% floodplain and may require it for homes in the 0.2% floodplain. Waiting to purchase flood insurance until you are contacted by the bank will forfeit the potential for the grandfathering. My next article will discuss implementing modern detention methods to increase buildable land and profit.
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.