Buffalo Bayou Hurricane Hike
Stop 6 // MANAGE //Sustainable Resilience?
North Bank of Buffalo Bayou South of Lee and Joe Jamail Skate Park
Figure 6.1. Google Earth image of the Jamail Skate Park area on September 2,2017, near the end of Hurricane Harvey’s early adjustment phase, approximately 2 days after the end of the flood phase. The sandbar (yellow) is presumed to be growing on a bench on the bayou designed to catch sediment.
Jamail Skate Park Sandbar
At this location (Fig. 6.1) an engineering attempt has been made to manage the storm and flood impact, resulting in intended and unintended consequences that are used here to spark a discussion about what is sustainable resilience. When considering storms and flood should we wait and pay or anticipate and accommodate?
In the 1950’s this bend in Buffalo Bayou was modified to collect sediments before they could flow downstream into the Houston ship channel. The design is very effective. Tons of sediment have been trapped in this man-made catchment. The 2019 Hurricane Imelda deposits (Fig. 6.3) sit on top of 2017 Hurricane Harvey deposits (Fig. 6.2) which sit on top of 2015 Memorial Day flood deposits, which in turn overlie older deposits. The good news is that approximately 2000 cubic meters of sediment that accumulated on the designed bench was prevented from being carried (Fig. 6.4) downstream into the ship channel. The bad news is that 2000 cubic meters of sediment was stranded in Buffalo Bayou Park, increasing local flooding potential and disrupting park use.
Figure 6.2. View looking southeast (downstream) of the skate park sandbar and the downtown skyline. The red line on the bridge marks the high water level at the end of the flood phase of Hurricane Harvey. The red line on the sandbar marks the base of the corresponding scour surface from the Hurricane Harvey flood into the 2015 Memorial Day flood deposit.
Figure 6.3. Hurricane Imelda Sand Peel Sculpture site November 15, 2019, just before the Skate Park sandbar was removed. At the base of the peel are Harvey deposits. This image shows the second phase of making a peel when cheesecloth is laid over the exposed sand and a plastic polymer is painted on to the cheesecloth.
Storm over Storm
Figure 6.2 shows the site of Sand Peel Sculpture X in the Skate Park sandbar and its relationship to the peak Hurricane Harvey water level. This portion of the Skate Park sandbar was forming during the middle adjustment phase of Harvey (Figure 6.1). Below the Hurricane Harvey deposits are deposits from the May, 2015 Memorial Day Flood.
Two years after Hurricane Harvey, on September 19, 2019, Hurricane Imelda flooded the Jamail Skate Park area reworking and depositing another package of sediment as seen in Figure 6.3 and the site of Sand Peel Sculpture Imelda. This stacking of multiple storm event archives illustrates how the coastline we live on is a composite stack of many millennia filled with storm events. Storms are what make the land we live on in Houston; we need to be better at adapting to them.
Figure 6.4. View looking south of the skate park sandbar ~100 days after Harvey during the recovery phase, two years before it was removed.
Figure 6.5. View looking down stream on October 2019 during the GeoGulf field trip, of the skate park sandbar as it was being removed during the Hurricane Harvey recovery phase.
Two months later, in November 2019, the 2000 cubic meter Skate Park sandbar was trucked out (Fig. 6.5). Figure 6.6 shows the partially removed Skate Park sand bar and the slope re-contoured to catch future storm sediments. A sustainable resiliency discussion needs to be had: is it better to catch the sediment here and increase the risk of central Houston flooding, or allow the sediment to flow downstream and fill the ship channel?
Figure 6.6. View looking up stream on October 2019 during the GeoGulf field trip, of catchment bench with the half-removed skate park sandbar. Approximately 2000 m3 of deposits from Hurricane Imelda, Hurricane Harvey, Memorial Day and other storms are being removed and the slope recontoured to catch future storm sediments. A sustainable resiliency discussion needs to be had on, if it is better to catch the sediment here, and increase the risk of central Houston flooding, or allow the sediment to flow downstream and fill the shipping channel?
Anticipate and Accommodate
The questions of sediment collection in the ship channel vs flooding in downtown illustrates how storm mitigation designs do not make the problems—too much water, too much sediment—disappear, but primarily shift them to somewhere else. There needs to be a continuous discussion of resiliently sustainable choices in how and where we shift the impacts of storms. In 2019, the 2000 cubic meters of sediment on the Skate Park bar were trucked out and the park recontoured. The 1950’s design worked but at the cost of increased flooding in the heart of Houston and disruption of a major recreational asset. When did or will the value of at-risk assets along the Bayou surpass the cost of dredging the ship channel? Would it have been more cost-effective and efficient to redesign the bench so sediment is allowed to flow to the ship channel? These are the types of discussions that need to occur so resilient choices can be made. We need to “change the paradigm from wait-and-pay to system-wide anticipate-and-accommodate” (HuRRI 2020).
Figure 6.7 Composite image of storm deposits at the Lee and Joe Jamail skate park. Three storms over four years are recorded in ~ 1-2 meters ( 3-6 feet ) of sediments.
Two months later, in November 2019, the 2000 cubic meter Skate Park sandbar was trucked out (Fig. 6.5). Figure 6.6 shows the partially removed Skate Park sand bar and the slope re-contoured to catch future storm sediments. The sand peels from this location (Fig.6.7) are achieves of storm events stacked over storm events, just waiting for the next storm. A sustainable resiliency discussion needs to be had: is it better to catch the sediment here and increase the risk of central Houston flooding, or allow the sediment to flow downstream and fill the ship channel?