The January 2018 quarterly report for the Atlas 14 project is available on the NOAA / NWS website.  See these prior posts to learn more about how Atlas 14 is an updated  statistical analysis of rainfall records to adjust our estimate of rainfall depths and likelihoods.

Schedule Change

The progress report indicates the following new schedule:

1. January 2018: Completion of peer review. [No change]
2. April 2018: Revise statistical data. [Was February 2018]
3. July 2018: Documentation and additional calculations. [Was March 2018]
4. October 2018: Web publication of final Atlas 14 data. [Was May 2018]
5. December 2018: Web publication of documentation. [Was June 2018]

Climate Change

The January 2018 report also summarizes the Atlas 14 work regarding how climate change may change rainfall depths in the future. The report uses the term “non-stationary climate” when referring to climate change.  The main tasks include:

1. Selection of non-stationary statistical analysis to determine future rainfall [underway];
2. Testing the feasibility of incorporating future climate projections into precipitation studies [complete by March 2018];
3. Implementation of selected non-stationary method(s) using historical and future precipitation data on a designated project area [not yet scheduled];
4. Assessing the added value of new precipitation frequency estimates
   with respect to traditional NOAA Atlas 14 estimates and recommending an approach for national implementation [not yet scheduled].

After making some posts about other people’s post-Harvey project ideas and after making some posts about policy principles I figured I should get real and specific about what I would suggest we do. Here’s my list.

1. Finish Federally Authorized Projects:  We should finish the currently federal authorized projects that have been underway for a long time, due to the lack of consistent federal appropriations each fiscal year.  These projects include Addicks and Barker Reservoir Dam Safety Work, Cedar Bayou, Clear Creek, Brays Bayou, Greens Bayou, Hunting Bayou, Sims Bayou, and White Oak Bayou.
2. Address Older, Higher Risk Areas:  We should evaluate other channels, creeks, and bayous and invest in conveyance improvements and detention that would remove the highest number of residences from the 1% annual chance floodplain. We have some older areas of our region that have a 5 or 10% chance of flooding each year – risk levels much higher than 1% annual chance — which is our modern standard.  These higher risk areas were built before the adoption of our current standards or they may sit on lower elevation ground.  Using the highest number of residences (instead of property value) in our benefit-cost calculation would help address equity and fairness concerns expressed by some.
3. Make Drainage System Improvements: After the bayous and channels are enhanced, we should upgrade our streets and drainage systems that take water away from buildings and discharge it to our bayous and channels.  This should be done in areas that have the highest risk of flooding and where the work will reduce flooding risks for the highest number of residences.
4. Make Targeted, Contiguous Buy-Outs: We should implement mandatory buy-outs of contiguous properties with the highest risk that won’t be helped by Items 2 and 3 above.
5. Implement Micro-Targeted Wireless Emergency Alerts: We should implement an updated wireless emergency alert system to warn residents of flooding or high rainfall. This system should utilize recently proposed Federal Communications Commission enhancements to the alert system, in particular, the ability to geographically target alerts to within a tenth of a mile. This should be rolled out as soon as possible, after the adoption of the new FCC rule, assuming the proposed rule is finalized and implemented by the wireless industry.
6. Build Traffic Warnings and Barriers:  We should install automatic flashing lights and gate arms (triggered by water level sensors) at all below-grade roadways in the region to reduce the number of driving fatalities and injuries during large rain events.
7. Evaluate Benefit-Cost Curve, Then Build Storm Surge Barrier: We should build an environmentally sensitive storm surge barrier. This would need to address concerns regarding the productivity of Galveston Bay, salinity gradients, currents, fish passage, and many other issues. The length and height of the barrier should be established so that this relationship would hold true:

The Net Present Value (NPV) of
construction costs
plus
costs of 100 years of operations and maintenance
(at a 5% discount rate)
is less than
the product of
the damage estimate
from a hurricane storm surge
multiplied by the
probability of the surge occurring
during the 100 year period.

For example, if the probability of that particular “worst case” storm surge hitting Galveston Bay during the 100 year analysis period was 1 in 500 and the damage estimate for such a surge was $2 trillion dollars, we would be justified in setting aside $2 billion today to fund barrier construction and 100 years of its operation. This relationship could be used to evaluate a range of storm sizes, paths, climate change scenarios, and probabilities until a reasonable balance between the planned investment level, the probability of incurring losses, and the value of potential losses avoided was reached.

This example is merely to illustrate how the avoided damages times the probability of that loss must be used to evaluate our level of investment.  If we don’t do this we can very easily over-spend to reduce risks too much or to avoid damages that have a very low likelihood of occurring, or both.

In summary, I support additional investments to reduce risks to the most people in the most environmentally responsible and sustainable manner, as long as the equity- adjusted benefits outweigh the likelihood-adjusted costs.