Let's review the facts before this teachable moment fades away.

We live on a very flat coastal plain — much of it only a four-foot drop over a mile. And much of it with very clayey, slow-to-drain soils. We also live in the region of highest-intensity rainfall in the continental U.S. So it is going to flood. Mother Nature will continue to deliver floods no matter what we do. Don’t count her out.

Flooding does not occur uniformly across the region. There are floodplains, and areas near the floodplains. There are low areas and there are higher areas. We need to know where these are. Obviously! — and yet we don’t seem to know.

But humans have screwed things up royally.

First, we have placed development in harm’s way — in low-lying areas, including floodplains. Incredibly, we continue to do so. Arbor Court Apartments — so much in the news with the heart-rending pictures of rescued families — is in the floodway of Greens Bayou. The floodway is the deepest part of the floodplain. The flooding at this point was inevitable — but the human tragedy was not. This was a disaster by design. Not Mother Nature’s fault!

And it’s not just lower-income housing: Wimbledon Champions Estates, at the confluence of Cypress Creek and Spring Gully, was also in the news this week. How would you not expect flooding at this location? Did the homebuyers understand the risk? This area was mapped as the 500-year floodplain — could the risk have been underestimated for this development? Whether or not there was some intentional manipulation of the lines, we should perhaps recognize that what we call the 500-year floodplain should be treated as a high-hazard zone, and not just the 100-year floodplain. In other words, don’t build there! But we have built in these kinds of areas all over the metro region. These, for the most part, are where the rescues have been taking place this past week.

We have also screwed up by paving over vast areas of land without mitigating the damage through appropriately-sized detention basins or by building green stormwater infrastructure (things like swales and rain gardens). In this, we have enlarged harm’s way by pouring more water into already overburdened waterways, and thus expanding the floodplains. But even worse, we have destroyed thousands of acres of depressional wetlands on our prairies and in our forests. These wetlands detain stormwater — stormwater that becomes floodwater.

We are currently in our last hard drive to destroy what’s left of those wetlands. The Grand Parkway is opening up vast new lands for development. You think it’s bad now — let’s see what happens with another 20 years of development on our periphery.

Another fact: Half of the built environment in the Houston of 2040 has yet to be built. This means that where and how we choose to build could have a major impact. It means there are choices to be made. It is not about not developing. Three to four million more people are coming our way. We will need developers to accommodate these folks. But perhaps we should do it differently.

We have been telling ourselves that Houston just cannot regulate anything. Our laissez-faire banner proclaims: Only the market rules! We have to get over this. Houston can no longer be about the quick turn of the dollar, about the quick-flip-of-a-subdivision-and-we’re-outta-here. This has to change. We must now build for the future, not the quick profit.

There are ways that we can control our future development through market-based solutions, if we would just exercise both a little political will and our imaginations. Paving over the prairie and its wetlands has a cost in terms of flooding damage, but that cost, possibly many thousands of dollars per acre, is not figured into the cost of development. That is not free market — that is a market distortion. Somebody always has to pay. Just because the developers, and the buyers of houses in the development, don’t have to shoulder the cost of damages doesn’t make it free. A tax that reflects the true cost would be an automatic incentive to look for places where development results in lower damages.

There are other methods. A Transfer of Development Rights system, for example, allows a landowner to move development rights from a location where development might be harmful to a location where development might be preferred. There are many ways such a system could be configured. Details are less important right now than just making sure that these kinds of things are on the table.

One final fact: A prominent urban demographer has calculated that the existing supply of single-family detached homes is greatly in excess of what the market will call for in another decade or two. This is because of changing demographics: Graying baby-boomers want a low-maintenance lifestyle, and millennials prefer walkable, dense urban environments, whether inside the Loop or in suburban centers. Single-family detached homes are exactly what we are building as we eat up the prairies to our west and the forests to our north. What will happen to the home values of the subdivisions when the market is no longer there for this quantity of homes? Does the short-term gain from these developments outweigh the flood-detention benefits the destroyed natural areas would have provided?

So, Mayor Turner, thus starts your watch. What better time to make changes, difficult though they may be? We need serious leadership on this. I think that’s what we elected you for.

John Jacob is board chair of Galveston Baykeeper when he has his advocacy hat on, and professor and extension specialist with the Texas A&M AgriLife Extension Service and Texas Sea Grant when he has his scientist hat on. Whichever hat is on, the opinions expressed here are his own. Jacob directs Texas A&M’s Texas Coastal Watershed Program in Clear Lake.

Read more Gray Matters. It's not the quick-flip-of-a-subdivision-and-we're-outta-here.