Myth #1: If we have three 100-yr floods in the space of 3 years, development and bad engineering must be to blame!

The 100-yr flood is the average period between rain events of certain size. There is a 1% chance of that size rain occurring EVERY year.  There is a 26% chance of that size storm occurring during a 30-yr mortgage.

Myth #2: Development makes flooding worse.

New development must include places to store water and must prove that flood levels in the area are not increased. New development does not increase flooding levels.

Myth #3: If you live somewhere for 30 years without a flood and you get flooded, something on the ground changed to cause it.

Flood waters come from rain. If you avoided flooding for 30 years it likely means that no large rain events occurred in your area.  A flood in your area probably resulted from an abnormally large rain event.

Myth #4: The streets in my area flood because of incompetence and mistakes.

Our flat terrain does not provide many places for the water to go, so we use the streets.  The streets are designed to flood above a certain size rain event to avoid flooding homes and business.

Myth #5: They are using outdated and old approaches to address drainage and flooding.

We use lasers to map the ground surface, we use advanced computer models to predict where water will flow and how high it will get.  We are now using “natural drainage” systems and “natural channel design” approaches in many projects.

Myth #6: Fill dirt used to raise a property for a new building causes flooding.

Site changes must be planned by a professional engineer. Places to move and store water must be provided. The engineer must prove that flood levels in the area are not increased. New development does not increase flooding.

Myth #7: Preserving greenspace will prevent flooding.

Preservation plays a role and can help, however new development is required to mimic the pre-development conditions. It is important to remember that Houston was flood prone prior to any development.

Myth #8: Widening and deepening all the bayous will prevent flooding.

It can help, but existing homes and businesses are frequently in the way and may be lower than the bayous banks.  Houston’s flat terrain limits how deep we can dig.  In many cases the issue is getting the water to the bayou.

Myth #9: Flooding is terrible because none of these new developments are following the rules!

Registered professional engineers must make all plans and follow regulations. Local governments must approve all plans. Inspectors check that construction is done according to these plans.

Myth #10: We can just rebuild all of the storm pipes and channels and everything will be fixed.

We are making new investments in drainage and flooding systems every year, but there are many pipes and channels that were built before the 1980s. To reduce the risk of flooding for everyone to less than 1% each year would take about $29 billion.