Storm-Surge Induced Water Level Changes in the Odra River Mouth Area (Southern Baltic Coast)

The Odra River mouth area is a region of the Southern Baltic coastal zone especially prone to the influence of storm surges. In the present study, the height and extent of the Baltic storm surges, and temporal offsets of the respective maximum water level occurrences in the Odra River mouth area were explored using cross-correlation, cluster analysis and principal component analysis. The analyses were based on hourly water level readings retrieved from water gauging stations located along the lower Odra reaches and at the coasts of the Szczecin Lagoon and the Pomeranian Bay during storm surge years 2008/2009–2019/2020. The analysis of mutual relationships between water levels during storm surges indicated that the extent of marine influence on the lower Odra River and within the Szczecin Lagoon was variable during the studied surge events, and dependent on meteorological conditions (the strongest during the sustained occurrence of wind blowing from the northern sector), discharge from the Odra River catchment (the strongest at low discharge), ice conditions on the lower Odra (suppressing the storm surge propagation upstream), and general sea level in the Pomeranian Bay (stronger at high sea levels). The strongest correlation between sea levels at Świnoujście and water levels in the Szczecin Lagoon and the lower Odra was found at a 6–7 h offset. The extent of storm surges usually reached 100 km up the lower Odra channels, less frequently reaching 130 km away from the sea.

Hydrodynamic and hydrochemical evolution of the Bajo Guadalhorce Valley alluvial aquifer (Málaga, S Spain) in the last 40 years

<p>Groundwater flowing through coastal aquifers is increasingly impacted by human pressures as consequence of a growing demand on drinking water, tourism and agriculture, among others. Thus, groundwater availability very often depend on its quality since water salinization and pollution are the main challenges for water management because of seawater and freshwater interaction. Therefore, it is crucial to monitor the availability of groundwater and its quality under changing scenarios where this water resource can be specially threatened.</p><p>This study aims to assess the spatial distribution and time evolution of groundwater levels and hydrochemistry of the alluvial aquifer of the Bajo Guadalhorce Valley (Málaga, S Spain) for the evaluation of its quantitative and qualitative status. To that, groundwater level, electrical conductivity and Cl<sup>-</sup> and SO<sub>4</sub><sup>2-</sup> concentrations of water have been measured in a field sampling campaign carried out in the alluvial aquifer of the Bajo Guadalhorce Valley (Málaga, S Spain) in April 2017. Additionally, historical data from the last 40 years have been compiled.</p><p>Results show that groundwater generally flow towards the Guadalhorce River, where gaining relationship remains more patent in its lower river stretch, and the Mediterranean Sea. Some negative groundwater elevations close to the coastal fringe are observed in several piezometers because of pumping during the study period. Electrical conductivity values were, generally, lower than 4 mS/cm in all samples and the major changes in groundwater mineralization were determined in the Guadalhorce River Mouth. In this aquifer sector, substantial increases in groundwater mineralization were identified, up to 50% in some observation points. Cl<sup>-</sup> and SO<sub>4</sub><sup>2-</sup>concentrations in groundwater (the more concentrated solutes of all) evolve similarly in time to that of electrical conductivity, with maximum recorded values up to 10000 mg/l and 2000 mg/l, respectively, the coastal area in 2017.</p><p>Changes in EC and Cl<sup>-</sup> and SO<sub>4</sub><sup>2-</sup> concentrations in the river mouth area could be related to the land use changes that took place here between 1997 and 2003, where channelization works resulted in the splitting of the river in two branches. This could have affected to the aquifer hydrodynamics, due to the reduced groundwater discharge to the river mouth area between both branches. This could have favored the mixing among surface water, sea water and groundwater. Also, the urbanized area has increased over the years, reducing the recharge area of this part of the aquifer, but also flowing groundwater has increased because of pumping reduction (up to 7 hm<sup>3</sup>/year). The presence of Cl<sup>- </sup>in the aquifer, as well as SO<sub>4</sub><sup>2-</sup>, is due to evaporite dissolution and the interaction with the Mediterranean Sea in the coastal area. An extra input of SO<sub>4</sub><sup>2-</sup> comes from of the fertilizers used in agriculture.</p><p>The availability of long-term hydrogeological data in a coastal aquifer (1976-2017) has allowed to check a remarkable salinization in the coastal area, caused by land use modifications. So, the monitoring of hydrogeological data is a very important tool to be used by land managers in coastal aquifers, where groundwater can be seriously endangered by human activities.</p>

PHÂN TÍCH BIẾN ĐỘNG ĐƯỜNG BỜ KHU VỰC BỜ BIỂN CỬA SÔNG HẬU BẰNG TƯ LIỆU VIỄN THÁM

Multi-temporal Landsat data are used for this study over the period of 1989 to 2016 with imageries of 1989, 2001, 2009 and 2016. Band rationing method and threshold technique are applied for the coastline extraction. The Digital Shoreline Analysis System ENVI 5.1, eCognition and ArcGIS 10.3 are used to calculate shoreline rate-of-change statistics from multiple historical shoreline positions. The results show that shoreline change in the Hau river mouth area has a trend of deposition between 1989 and 2016 (27 years) with the accretion area ranging from 162.68 ha to 1,210.83 ha. Meanwhile, the erosion area only ranges from 0.002 ha to 183.53 ha. The results obtained from this study set a stage for new studies to understand the morphological changes of the river mouths in the Mekong Delta and coastal areas of Hau river.

PENGADAAN ECO-LIBRARY BERBASIS PENGELOLAAN SAMPAH DI DESA KILENSARI KECAMATAN PANARUKAN KABUPATEN SITUBONDO JAWA TIMUR

This activity was aimed to solve the problems related to the lack of awareness and understanding of the community in Kilensari Village, Panarukan Subdistrict on proper waste management. Based on preliminary observations, people dump garbage around the river mouth area. It caused environmental degradation, threats to aquatic organisms, and risks to human health. To overcome this, the proposed establishment of eco-library as a means of education and socialization to the community for better waste management. The establishment of an eco-library involves NGOs engaging in environmental literacy, Greenbooks.org. This NGO acts as an online instructor on environmental education activities provided. Based on interviews with Head of Kilensari Village, there has been a plan for making temporary garbage collection (TPS) in Kilensari Village which will be built in 2018 with total area of ± 3Ha. The socialization of eco-library was held on 15 November 2017 at Kilensari Village Hall, Panarukan Sub-district. Communities participating in the socialization activities were quite enthusiastic about the establishment of an eco-library and a plan of cooperation with Greenbooks.org for environmental learning for children. It is hoped that socialization and training activities related to waste management can continue, so that people understand and implement waste management properly. Initially, the eco-library was proclaimed to have a collection of waste management-based books targeting children's readers aged 6-18. But as the program progresses, the books are not specially discussed about waste management, but still themed environment and living creatures. Cooperation with Greenbooks.org will begin with registration of eco-library in Kilensari Village.