Floodplain - To build or not to build?

Question

Group,

As a commercial GC, I've built many projects in the 100 year flood plain for clients. As an aspiring commercial developer, I tend to look at properties that I believe are GREAT opportunities based on location and price per acre/foot that fall in these flood zones. Aside from additional detention volume, mitigation,  and raising the elevation, what are some other factors I may need to consider that are more technical than moving dirt.

I always plan on engaging with a civil engineer during the due diligence phase so I will know if a property will be suitable for my proposed development.

Henry Clark · Answer

OP not sure on what you mean by more technical.

1.  Keeping water flow into the downstream neighbors property the same.

2.  Do you create a damming effect causing a portion of a neighbors property to now be in a flood zone.  3.  Sewage lift pump.  Do you have enough “fall” across your property, or do you need a lift pump.

4.   Storm drains.  Do you have enough “fall” to connect to the city or reach a storm pond.  5.  Surface coverage versus drainage.  Example.  If you have say 80% building coverage that drains onto a drive say 5%, it will flood your building.  Grew up in LA and TX.  The most unexpected place I saw this was Lubbock TX.  The town would flood because it was so flat and had to much building coverage for the drainage.

Alecia Loveless · Answer

@Brent Thomas The current cost of flood insurance for a building in a flood plain may need to be considered.

I just looked at a 4 plex in a flood plain. The homeowners insurance was about $2500 but the flood policy was $10,000.

This alone was enough to deter me from any further consideration of this property as without factoring in any other information $1000+ per month in insurance ate up any cash flow that there might be otherwise.

Phillip Wilshire · Answer

Hello Brent, I'm in Houston Tx, Phil

Jamie Hora · Answer

The impact of additional design effort & permitting to the timeline of the project.  Modeling the floodplain can be significant work for the civil, and then permitting time with FEMA can be extensive.