Author: jrt

The flooding in Houston associated hurricane Harvey was primarily due to release from the Addicks and Barker reservoirs which flooded the Buffalo Bayou river.

The dramatic change in water level in Buffalo Bayou is best illustrated by photos taken above the Barker Reservoir flood control station before and immediately after the hurricane struck.

Our project is driven by the need to determine the water depth over roadways.  The impact of the Barker flood release on the local infrastructure is illustrated by the flooding over Hwy 6 which is adjacent to the Barker flood control station and passes over Buffalo Bayou.

Our problem specifically involves developing a metric that we can use to determine whether a road is passable or not.  While a quantifiable metric would be most desirable, we expect quantification to be difficult.  We have considered a metric involving a set of classes: dry, wet, flooded; however, these are still difficult classifications to develop from purely optical data.

One idea that we have kicked around is that we can see road markers in relatively shallow water and as the water depth increases, the opacity of the water rapidly increases due to the turbidity of flood waters; however, our intuition suggests that this approach will encounter difficulties because as water settles, the sediments will ultimately obscure road markings regardless of the depth.  The following pictures are close-ups of the Hwy 6 area around Buffalo Bayou.

We can clearly see where the water line is in the above pictures, and we believe that this is information that we can train on with a human in the loop.

When Nick found out that my background is computer simulation, he proposed that we use elevation models (DEM or LIDAR data) to simulate water movement in an area.  I was not too receptive to the idea because water simulations can be really complex problems dependent on Computational Fluid Dynamics (CFD) which may require massive computing resources.  The important consideration from this discussion though was the potential inclusion of DEM data into our training regime.

We believe that we can incorporate the elevation data with optical data to determine water depth based on the assumption that the "localized sea level" is roughly constant.  If we locate the water line in a number of locations, we can use that elevation to define the localized sea level and can then determine depth of features throughout the local area.

Some infrastructure may be of particular interest.  For example, the central span of bridges are level for structural reasons.  The following image shows the Park Row bridge over the Addicks reservoir outlet.

I now have access to all of the satellite platforms that will be used with the GCA project and I have begun familiarizing myself with the platforms.  I will be attending training seminars for two of the platforms, today and tomorrow, to get a deeper understanding of the systems.

I also have a meeting with Nick Tom at DZYNE today to discuss the metric in preparation for the Phase 2 kickoff meeting presentation scheduled for March 12 and 13.  We also have a government meeting scheduled for Monday March 4.  These appointments are reflected in the GCA calendar.

Robert and I discussed the metric that was proposed in preparation for meeting with Nick over the metric.  Our current plan is for me to focus this upcoming week on gathering data to support the presentation of that metric at the Phase 2 kickoff meeting.  At this point, the data we are looking for is a range of images that support classification of traversability of a road, e.g. dry, wet (no accumulation), 2" deep, 6" deep, undrivable (boating depth).

Last week Robert and I met to discuss the project.  While we are funded under the overall grant, our category is more freely categorized as "suggest your own".

The primary team has a general focus on hurricanes; however, we are all keenly aware of the limitations that local and potentially long-term weather that a hurricane will impose on imagery.  Much of the primary team is looking at other spectrums to try to peer through clouds in order to make observations of the ground, structures, and infrastructure.

Given our less constrained task, Robert and I have been considering other extreme events that avoid the problem of weather.  The two best candidates are tornadoes and tsunamis.  For tornadoes, the fronts are fast moving and do not typically linger for days.  For tsunamis, the triggering event is generally an earthquake and is not subject to weather events.  These classes of disasters suggest that we can deliver a product that focuses on the heart of the problem and is not subject to the broad number of ancillary problems associated with hurricanes.

We met this Nick at Dzyne and posed this alternative.  We will be searching for imagery in these areas using the available databases.

The onboarding process is proceeding.  I have been given access to a number of imaging databases and we have scheduled a number of training sessions with the different services.  We will have a large training meeting next Thursday.

As far as future schedule, the next government tag-up is scheduled for Monday (2/25) at 2:30p and Phase 2 Kickoff is scheduled for March 12-13.

I think Robert and I will need to discuss what can be posted publicly due to the nature of this research, so this post reflects only part of the information shared in the GCA meeting held this week.

Phase 2 kickoff will scheduled for March 12 or 13th.  At this point meetings will become bi-weekly rather than monthly.  The proposed schedule for meetings is every other Monday at the same time as the monthly tag-ups.

Phase 1 has been pulling data from Digital Globe and Descartes Labs.  These data sets include data covering typhoon and hurricane affected areas.  Some of these data sets contain significant cloud cover.

There is consideration of using radargrammetry via Radar Sat data as a low resolution filter so that only optical data from areas of interest will need to be processed.

This is primarily a test post.  However, on Monday I will attend the first meeting with DZYNE and the remainder of the disaster relief project and I should have more of a basis to report in future discussions.