The «Empty Forest Syndrome» and the Herpetofaunal Communities in Laos (South-Eastern Asia)

Nowadays, Laos remains one of the scientifically least known countries of Asia in terms of herpetological knowledge. Here, we evaluate composition of species in freshwater ecosystems (main river courses) and terrestrial ecosystems (forests) in two distinct regions using Visual Encounter Surveys along designed transects, examination of fishers’ catches and standardized interviews. In Northern Laos, we recorded only 18 reptile individuals (2 turtle and 1 snake species). Interview surveys demonstrated that in Nam Xam River, fishers are more likely to hunt turtles and we identified one potential site where the world’s rarest turtle, Rafetus swinhoei, could be still present in the wild. In Nam Et Phou Louey National Park, we found 19 reptile species (8 lizard, 10 snake, 1 turtle species) in the different study sites, demonstrating a low species density in all different surveyed habitats. In Central/Southern Laos, we observed 30 species of reptiles (14 snake, 16 lizard, 35 amphibian species). Our study offers preliminary insights into the composition of amphibians and reptiles in Laos. The great majority of the species were non-threatened or not evaluated, and a few were threatened, suggesting that more research is needed to proper understand the conservation status of Laos’ herpetofauna. We highlighted, indirectly by interviews with local fishers, the possible presence of the turtle Rafetus swinhoei, thus providing a new hope for avoiding the extinction of this species. Finally, we observed a relatively low number of species in each habitat type, which is remarkably lower than in tropical forests of other continents or of nearby south-east Asian countries, indicating that the herpetofauna communities in Laos are depleted, reflecting an ‘empty forest syndrome’.

Material Culture of the Horizon of the 10th Century at the Hillfort near Spitsino Village

The article presents the results of research in 2019-2020 of the 10th century settlement on a multi-layered hillfort near the village of Spitsino (4th -5th, 10th centuries). The monument is located at a considerable distance from the main river routes in the region, which excludes its relationship with the Upper Oka section of the Don trade route in the 9th -10th centuries. A significant part of the finds discovered during exploration 2019, are of Northern European origin and date back to the mid. - 2nd half 10th century. There are also a few finds related to steppe antiquities. According to the materials of the excavations, the buildings of two construction periods are identified. The ceramic complex of buildings of the early construction period is represented by fragments of stucco vessels of the Romaine type and redeposited fragments of vessels of the 4th - 5th century. Fragments of early vessels made on a potter's wheel dating from the second half of the 10th century are found in the ceramic complex of the late construction period. Thus, the monument can be attributed to the period of the middle - second half of the 10th century. This period until recently represented a chronological lacuna in the period of Slavic colonization of the region.

Identification of the contributing area to river discharge during low-flow periods

The increasing severity of hydrological droughts in the Mediterranean basin related to climate change raises the need to understand the processes sustaining low flow. The purpose of this paper is to evaluate simple mixing model approaches, first to identify and then to quantify streamflow contribution during low-water periods. An approach based on the coupling of geochemical data with hydrological data allows the quantification of flow contributions. In addition, monitoring during the low-water period was used to investigate the drying-up trajectory of each geological reservoir individually. Data were collected during the summers of 2018 and 2019 on a Mediterranean river (Gardon de Sainte-Croix). The identification of the end-members was performed after the identification of a groundwater geochemical signature clustered according to the geological nature of the reservoir. Two complementary methods validate further the characterisation: rock-leaching experiments and unsupervised classification (k-means). The use of the end-member mixture analysis (EMMA) coupled with a generalised likelihood uncertainty estimate (GLUE) (G-EMMA) mixing model coupled with hydrological monitoring of the main river discharge rate highlights major disparities in the contribution of the geological units, showing a reservoir with a minor contribution in high flow becoming preponderant during the low-flow period. This finding was revealed to be of the utmost importance for the management of water resources during the dry period.

Evaluation and space representation of the maximum surface runoff in watersheds

In Cuba, regardless of the advances made in hydrological and hydraulic investigations related to floods, there are limitations with the detailed knowledge of the true maximum surface runoff or maximum flow that characterizes these phenomena in the season of intense rains, for which it is necessary to carry out complex hydrological study that, with the help of professional software and statistical techniques, help to determine and model spatially with certain reliability, the maximum water surface drained in watersheds. The general objective was pursued: To determine and represent spatially with the use of Geographic Information Systems (GIS) and hydrological methods, the runoff or maximum flow produced by the intense rains in a watershed, selecting to exemplify the watershed from the Magdalena River to the south east of the Santiago de Cuba municipality. As a result was obtained in the first instance, that it is feasible to apply this procedure to know in a preliminary way what maximum flow is available at any point of a main river or tributary. This approximation constitutes a significant advance for subsequent work in other watersheds of Cuba or internationally.

The Effect of Urban Drainage on The Determination The Time of Storage In The City Development Area

Increasing development activities in various fields in Surabaya will impact the occurrence of flooding, where the growth of residential buildings changes the function of the drainage area into runoff land. Therefore, there is a need for regional drainage recommendations. This study aims to provide a reference for a safe number that follows the storage needs and the duration of the peak partial drainage required by the region, following the study of water resources science. The data needed are rainfall data, average area, land function, and land slope maps. This study uses a 5-year return period probability. Moreover, the Nakayasu Hydrograph method is also used. It has a grace period starting from the rain surface to the top of the hydrograph, the area of the watershed, and the length of the main river channel. The comparison of the length of time of concentration (Tc) of the area with the length of waiting for time (Tp) of the urban drainage hydrograph shows that the area’s Tc value is greater than the Tp value of the urban drainage.

Impact Des Aménagements Hydroélectriques Sur Le Peuplement Des Poissons Du Lac De Barrage De Buyo Et De La Zone Périphérique (Côte d’Ivoire)

L’objectif de ce travail était de déterminer l’impact des variations des niveaux d’eau sur la distribution des poissons dans le lac de Buyo et le cours principal du fleuve Sassandra. Les campagnes ont lieu de Juin 2018 à Mai 2019. Les changements hydrologiques ont été observés après la mise en eau d’un deuxième barrage sur le fleuve Sassandra. Ces changements hydrologiques ont eu un impact sur la diversité piscicole. Les poissons ont été capturés à l’aide des filets maillants et des nasses artisanales. Ces poissons sont repartis en 6 ordres, 14 familles et 42 espèces. Dans le lac de Buyo, l’espèce Synodontis punctifer domine le peuplement en période de crue alors que Coptodon zillii est prépondérante en période de décrue. Dans le cours principal l’espèce Synodontis punctifer domine le peuplement durant les périodes d’ouverture et de fermeture des vannes du barrage, cette espèce est plus adaptée aux changements hydrologiques. Une bonne organisation du peuplement est observée en période de crue dans le lac. Dans le cours principal, une bonne organisation du peuplement est avérée en période de décrue lorsque les vannes du barrage sont fermées. Le modèle de prévision a montré que dans le lac de Buyo, la richesse spécifique est influencée positivement les cotes de retenue mais négativement par le débit d’apport d’eau et le volume d’eau déversé. Dans le milieu fluviatile, le modèle a montré que la richesse spécifique est influencée négativement par la profondeur et le débit d’eau turbiné mais influencé positivement par la vitesse du courant. The objective of this work was to determine the impact of water level variations on fish distribution in Lake Buyo and the main course of the Sassandra River. The campaigns will take place from June 2018 to May 2019. The hydrological changes are proven after the impoundment of a second dam on the Sassandra River. These hydrological changes have had an impact on fish diversity. The fish were caught using gillnets and artisanal traps. These fish are divided into 6 orders, 14 families and 42 species. In Lake Buyo, the species Synodontis punctifer dominates the population during the flood period while Coptodon zillii is predominant during the low water season. In the mainstream, the species Synodontis punctifer dominates the population during the periods of opening and closing of the gates of the dam, this species is more adapted to hydrological changes. A good organization of the population is observed during the period of flooding in the lake. In the main river, a good organization of the population is proven during the flood period when the gates of the dam are closed. The predictive model showed that in Lake Buyo, the species richness is positively influenced by the impoundment rating but negatively by the inflow rate and the volume of water discharged. In the fluvial environment, the model showed that the specific richness is negatively influenced by the depth and the turbinated water flow but positively influenced by the current speed.

Life-Long Learning Know-How Transfer Centers for Flood Risk Assessment in Romania and Hungary

The sector affected by surplus or scarcity of water requires proper understanding of river and landscape system behavior, what is possible to be done to prevent potential damages and losses need skilled professionals, who are familiar also with the newest IT based hydroinformatic tools and technological achievements to find the best possible solutions. An extensive programs of Water Authorities in Romania and in Hungary have been running to provide flood risk maps in all the main river basins including also those which across the both countries. The obtained results will be contribute to the better understanding and general prediction of flooding on the major river systems and assist the governments to act (in real time and space) in accordance with contingency planning based on flood risk management plans, moreover future development plans of regions and cities will get a proper guidance and platforms for future feasibility studies. However Flood Directive implementation has been ongoing in Romania and Hungary, `bridging and direct trainings` for relevant sectors as it is planned in this project have not been provided and have not been planned for future in Romania and Hungary. Based on these needs in 2011 was initiated and organized an international cooperation project financed by the European Union with the theme: “Development of knowledge canters for life-long learning by involving of specialists and decision makers in flood risk management using advanced Hydroinformatic tools” [1]. In this paper we give a brief overview of the main objectives proposed, a description of the partners and some aspects of the activities developed in the project and some of the results obtained

The effect of land-use change on river watershed quality (case study: Cimahi Watershed, West Java, Indonesia)

Increasing population growth is one of the impacts of the growth of a city or district in an area. This also happened in the Cimahi watershed area. As the population grows, so does the need for land which increases the land-use change in the Cimahi watershed. Land-use changes will affect the surrounding environment and one of them is the river, especially river water quality. As a watershed area, there is one main river that is the source of life as well as the Cimahi watershed, whose main river is the Cimahi River. The purpose of this study was calculated the relationship between land-use change in the Cimahi watershed and the water quality parameters of the Cimahi River. The correlation between the two was calculated using Pearson correlation. Water quality parameters can be seen based on BOD and DO values. BOD and DO values are the opposite because good water quality has high DO values and low BOD values. The correlation between land-use change and BOD was 0.328 is in the area of settlements area. In contrast, to DO values, an increase in settlements/industrial zones will further reduce DO values so that both have a negative correlation, which is indicated by a value of -0,535. The correlation between settlements with pH and temperature values is 0.664 and 0.812. While the correlation between settlements with TSS and TDS values are 0.333 and 0.529, respectively. In this study, it can be seen that there is a relationship between the decline in water quality and changes in land use.

Fish Fauna of Ilisu Area on the Tigris River, Before Impoundment of the Ilisu Dam (Turkey)

The Ilisu Dam is a large hydroelectric power plant that started to collect water in 2019 on the Tigris River in Turkey. This study was done during the period 2010 to 2014 to determine fish fauna of the Tigris River and its tributaries related to the potential reservoir area of the Ilisu Dam before its foundation. 35 fish species belonging to 10 families have been identified in the main river and its tributaries to be covered by the dam reservoir. One of these species, Glyptothorax steindachneri was recorded for the first time from the Turkish part of the Tigris River. 22 species were found widely distributed. At least 16 species were found to be endemic to the Tigris and Euphrates basins. Three species were already recommended with some level of international protection as per IUCN Red List. Cobitis kellei and Paraschistura chrysicristinae species, whose type localities were reported as upper Tigris, were not recorded.

Sequential Damming Induced Winter Season Flash Flood in Uttarakhand Province of India

204 persons were killed while two hydropower projects located in close proximity at Rishiganga (13.2 MW), and Tapoban (520 MW) were damaged in Dhauliganga flood of February 7, 2021 in the Indian Himalaya. This incidence occurred during the winter season when the discharge of the glacier fed rivers is minimal, and no rain was experienced in the region around the time of the flood. Despite discharge of the main river, Rishiganga, not involved in the flood due to damming upstream of its confluence with Raunthi Gadhera, based on field evidences massive volume of around 6 million cu m water involved in this flood is attributed to sequential intermittent damming at three different places; (i) Raunthi Gadhera was dammed first in its upper reaches, (ii) Rishiganga river was then dammed to the north of Murunna, and (iii) finally Dhauliganga river was dammed around Rini village to the upstream of its confluence with Rishiganga river. Lacking warning system only enhanced the flood-induced devastation. Legally binding disaster risk assessment regime, together with robust warning generation, and dissemination infrastructure are therefore recommended for all major infrastructure projects.