Nearshore Hydrography along the Coast of Doha, Central Arabian Gulf

Aboobacker, V.M; Hasna, V.M.; Al-Ansari, E.M.A.S., and Vethamony, P., 2024. Nearshore hydrography along the coast of Doha, central Arabian Gulf. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 422-426. Charlotte (North Carolina), ISSN 0749-0208. Doha, the capital city of the State of Qatar has undergone substantial growth in population and infrastructure in the past few decades. Extensive land reclamation has resulted in changes in coastal morphology, especially on Doha Bay, the Pearl and the Lusail. Doha Bay is a semi-enclosed water body in the central east coast of Qatar. The characteristics of hydrography in the Doha Bay and adjacent regions are not well studied. This study presents the analysis of temperature, salinity, density, dissolved oxygen (DO), pH and chlorophyll-a collected off Doha (<15 m depth locations; 7 stations in all seasons; 4 other stations in 2 latest seasons) during October 2021, December 2021, June 2022 (pre-FIFA-2022), and March 2023 (post-FIFA-2022) using SeaBird CTD. The analysis reveals that the seasonal variations in temperature, salinity, density, DO and pH are statistically significant, while the horizontal variations are not significant. The chlorophyll-a has significant horizontal variability, while seasonal variability is not significant. There are four outfalls in Doha Bay, which discharges non-storm waters including groundwaters in limited quantity (0.114-1.241 m3/s). However, the changes in hydrographic parameters in the vicinity of the outfalls are marginal, except for DO. This has been verified when analysed the parameters during pre-FIFA-2022 (with discharges) and post-FIFA-2022 (no discharges) conditions. The sea surface temperature off Doha ranges from 27.8-29.0°C, 22.5-23.7°C, 28.0-29.2°C and 20.6-22.2°C, respectively, during the four seasons. The sea surface salinity ranges 39.3-40.6, 39.4-40.3, 37.3-39.2 and 40.6-42.0, respectively. The lowest salinity is obtained during summer, while the highest is obtained during winter; the latter is due to the relatively higher evaporation induced by winter shamal winds. The DO ranges 5.9-6.4, 6.5-6.8, 5.9-6.7 and 7-7.3 mg/l, respectively. The temporary closure of outfalls during FIFA-2022 has resulted in significant increase in DO, in addition to the well-mixing due to winter shamal winds. The pH ranges 7.80-7.90, 7.97-8.02, 7.86-7.99 and 7.70-7.77, respectively. The chlorophyll-a ranges 0.22-0.91, 0.17-1.45, 0.15-1.69 and 0.22-1.0 µg/l, respectively.