2.2. Sediment Sampling Post Harvey
Six deposited soil samples (dried soil left after Hurricane Harvey due to overland deposition) from the banks of Brays Bayou, and five deposited soil samples from the banks of Buffalo Bayou were collected on October 6 and October 9, 2017, respectively (Figure 1T). Brays Bayou is the most urban bayou in Houston, whereas Buffalo Bayou is characterized by its Addicks and Barkers flood control reservoirs that reached capacity during Harvey and released water that exacerbated flooding and significantly affected water quality in the Bayou (Kiaghadi and Rifai, 2019). Most of the stations where deposited soil samples were collected were located in residential areas except station B6 (Figure 1T) that was located in a commercial area. The deposited soil samples were only tested for trace metals and not for Total Organic Carbon (TOC) and grain size due to the dominance of white sand and silt. In addition, no microbial analysis was conducted on deposited soil samples due to their exposed nature to wildlife.
Bed sediment samples in the tidal segments of the HSC-GB estuarine system (referred to as bed sediment samples for the remainder of the paper) were collected from 11 sampling sites (see Figure 1B) during the period from October 6 to October 27, 2017 (6-9 weeks after Hurricane Harvey landfall). The number of samples was determined based on prior knowledge of the HSC-GB while taking into account limitations in budget and sampling logistics. Most of the bayous and streams were back to a normal flow regime at the time of sampling with the exception of Buffalo Bayou. In addition to lower flow rates from the discharging bayous, satellite imagery (see Figure S1 in the SI) showed that sediment transport had largely abated at the time of sampling. Thus, all sediment samples were collected when the system had reached quasi-equilibrium in terms of sediment transport and deposition. The details of bed sediment and deposited sediment sampling and quality assurance are presented in the SI.