Projected Impact of Sea Level Rise on Nigeria’s Coastal City of Calabar in Cross River State

This study projects the impact of sea level rise on Nigeria’s coastal city of Calabar in Cross River State. Data for the study were obtained from both secondary and primary sources through the use of the internet and questionnaire administration respectively. The data were analysed using the geographical information systems (GIS), frequency tables and percentages. The results revealed that at 0.3 m rise in sea level, about 4.56% of the total land area will be covered with flood water. This would affect 159 houses, with approximately 1,431 persons. Further, at 3.0 m rise in sea level, about 10.10% of the area will be flooded, affecting 2012 houses with an estimated population of 18,108 persons. Again, the resilience of the residents to the vagaries of flooding by sea level rise is generally low due to very low income and lack of awareness. The study concluded that Calabar City is vulnerable to the impact of sea level rise which is primarily caused by climate change. Therefore, awareness campaign on the impact of flooding by sea level rise on coastal communities should be carried out by the appropriate agencies of government in the State.

La dinámica oceanográfica frente al Humedal Nacional Térraba-Sierpe y su relación con la muerte del manglar / The oceanographic dynamic in front of Térraba-Sierpe National Wetland (HNTS) and its relation with the mangrove's death

Resumen Se estudió la dinámica de las mareas y el oleaje frente al Humedal Nacional Térraba-Sierpe (HNTS) y su relación con los procesos de erosión y la muerte del manglar en esta región. Se encuentra que un aumento relativo del nivel del mar, ya sea generado por el basculamiento de las costas, o por calentamiento global, es el responsable de crear una nueva plataforma para el oleaje y está modificando el perfil de la costa y cambiando el tipo de sedimento sobre el cual crece el manglar. Una mayor deposición de sedimentos sobre la región norte de este delta, mantiene el equilibrio de este sistema en esta zona, donde más bien hay una ganancia de sedimentos en la isla al frente de la desembocadura del Río Grande de Térraba. Un menor aporte de sedimentos del Rio Sierpe está generando una migración tierra adentro de este sistema estuarino frente a esta región, lo cual es un síntoma de un aumento relativo del nivel del mar. Los escenarios futuros sobre una mayor energía del oleaje, y de un continuo aumento del nivel del mar, no permitirán un equilibrio en la dinámica de los sedimentos, especialmente sobre la parte sur de este delta, por lo que continuará perdiendo la cobertura del manglar en este sistema estuarino.

Abstract The Térraba-Sierpe Reserve has the largest mangrove in Costa Rica but has suffered from changes in sea level. I used published data to analyze the area and found that sea level rise, generated by coast subsidence or global warming, created a new platform for waves and changed the beach profile and sediment type. Increased sediment deposition on the north maintains the balance of this system, with a sediment gain on the island in front of the Térraba river mouth. A lower sediment output from the Sierpe river is generating a landward delta migration, especially in the southern part, a symptom of local sea level rise. Future scenarios of greater wave energy and additional sea level rise will not allow a dynamic sediment balance, especially on the southern part of the delta, and will generate a loss mangrove cover. Rev. Biol. Trop. 63 (Suppl. 1): 29-46. Epub 2015 April 01.

Response Characteristics of the Perdido and Wolf Bay System to Inflows and Sea Level Rise.

The Perdido and Wolf Bay system in Alabama, USA, is an estuarine system linking the freshwater from the Perdido and Wolf Bay watersheds and the tidal saltwater from the Gulf of Mexico through Perdido Pass, Dolphin Pass, and the Gulf Intracoastal Waterway. A three dimensional hydrodynamic model using Environmental Fluid Dynamics Code (EFDC) was developed and used to analyze complex and dynamic flow, salinity, and temperature distributions in the system. The external driving forces for the model include the river discharges from natural and urban watersheds, atmospheric winds, and astronomical tidal elevations at the open boundaries where flow exchange takes place. Simulated water surface elevation, temperature, and salinity were compared against the field data at several observation stations in 2008 and 2009 with good agreement (coefficient of determination R2 = 0.92 between the measured and the modeled water surface elevations). The calibrated EFDC model was used to examine responses of the system to high, mean, and low inflows from streams and the sea level rise in the open boundaries under climate change. The concept of the age of water was applied to understand pollutant transport in the system. The age of water reveals dynamic and complex interactions between tides from the Gulf of Mexico and inflows from the streams. The age of water is less than 20 days under the 2-year high inflows and up to 160 days under 7Q10 low inflows. Under mean inflow conditions, the age of the tracer released from Wolf Bay is 50–70 days in the lower Perdido Bay and larger than that in the upper Perdido Bay, indicating a strong interaction between tides and inflows, which results in recirculation of flow and pollutants. The age of water is projected to increase up to 60 days under estimated sea level rise scenarios.

Assessing Effects of Climate Change on Biogeochemical Cycling of Trace Metals in Alluvial and Coastal Watersheds.

Assessing the impacts of climate changes on water quality requires an understanding of the biogeochemical cycling of trace metals. Evidence from research on alluvial aquifers and coastal watersheds shows direct impacts of climate change on the fate and transformation of trace metals in natural environments. The case studies presented here use field data and numerical modeling techniques to test assumptions about the effects of climate change on natural arsenic contamination of groundwater in alluvial aquifers and mercury bioaccumulation in coastal salt marshes. The results show that the rises of sea level and river base during the warm Holocene period has led to an overall increase in groundwater arsenic concentration due to the development of reducing geochemical

Sea-land limits: a case study

The limits between sea and land were estimated at "Pulso" beach located in the Southeastern Brazilian shelf (φ = 23°33/17.4886"S; Λ = 045° 13'13.0504"W - WGS84), between the island of São Sebastião and the city of Ubatuba, SP, Brazil. The relative sea level of the year 1831 at "Pulso" beach, as per Brazilian law Number 9760 dated from 1946, was estimated and materialized. The retro-estimation allowed the demarcation of the Legal Sea-Land Limits at "Pulso" beach as per the terms of the law. The accuracy of the procedure for the transference of the long-term sea level from the research station of Ubatuba to "Pulso" beach was assessed by parallel work of geometrical leveling referred to the IBGE (Brazilian Institute of Geography and Statistics) geodetic network. The motivation, the hypotheses (Brest, Cananeia and IPCC) and the methods here used are described, together with a short history of the Legal Sea-Land Limits. The results indicated that the legal Sea-Land Limits at "Pulso" beach are well within the beach area. They were determined as per law 9760, and there is the need to reactivate the national network of sea level gauge.

Os limites entre mar e terra foram estimados na praia chamada Pulso, localizada na costa sudeste do Brasil (φ = 23°33'17, 4886"S; Λ = 045°13'13, 0504"W) entre a Ilha de São Sebastião e a cidade de Ubatuba, no Estado de São Paulo, SP, Brasil. O nível relativo do mar do ano de 1831 na praia do Pulso, ou "Praia do Pulso" (PP), foi estimado e materializado, de acordo com a Lei brasileira Número 9760 de 1946. A acurácia do procedimento foi acompanhada por trabalho paralelo de nivelamento geométrico referido ao sistema nacional de geodésia do IBGE (Instituto Brasileiro de Geografia e Estatística). A motivação, as hipóteses (Brest, Cananeia e IPCC) e os métodos utilizados são descritos, acompanhados por um breve histórico dos "Terrenos de Marinha". Os resultados indicaram que os limites em (PP) estão bem dentro da área da praia. Eles fora deterinados de acordo co a Lei No. 9760 e há a necessidade de reativar a rede nacional de medidores do nível do mar.