Impacts of hydropower on the habitat of jaguars and tigers

The rapid expansion of hydropower across tropical landscapes has caused extensive habitat loss and degradation, triggering biodiversity loss. Despite known risks to freshwater biodiversity, the flooding of terrestrial habitats caused by dam construction, and associated impacts on terrestrial biota, have been rarely considered. To help fill this knowledge gap, we quantified the habitat loss following inundation of hydropower reservoirs across the range of two iconic species, jaguars and tigers. To do so, we compiled existing and planned dams intersecting the distribution of these apex predators. We found 164 dams intersecting the jaguar range, in total flooding 25,397 km2. For tigers, we identified 421 dams, amounting to 13,750 km2. As hydropower infrastructure is projected to expand in the decades ahead, these values are expected to increase greatly, particularly within the distribution of jaguars where the number of dams will nearly quadruple (429 planned dams). Despite the relatively few dams (41) planned across the range of tigers, most will intersect priority conservation areas for this species. We recommend a more cautious pursuit of hydropower in topographically flat regions, to avoid extensive habitat flooding which has occurred in the Neotropics, and avoiding dam construction in priority conservation landscapes for tigers.

Modeling the effects of land-use and climate change on the performance of stormwater sewer system using SWMM simulation: case study

Flooding of stormwater drainage systems represents a major problem in developing urban areas that could be influenced by land-use and climate change. Flooding problems can be assessed using simulation models such as the stormwater management model (SWMM). In this study, the generation of intensity duration frequency curves (IDF) that integrates climate change effect was conducted for Al-Najaf Governorate in Iraq for the first time. In addition, the effects of land-use and climate change on the stormwater sewer system of Al-Ameer District was simulated using SWMM. The results indicated that by increasing the sub-catchment area from 50 to 100%, an increment in total surface runoff from 20,380 to 37,350 m3, and total flooding from 10,513 to 26,032 m3 have occurred, respectively. As a response to climate change, changing the return period from 2 to 5 years has increased the total surface runoff from 14,120 to 27,110 m3 (representing 48% of raise), and total flooding increased from 5,914 to 17,591 m3 (accounting 72% of increment). To conclude, flooding locations and magnitude were identified, whilst the system failed to discharge surface runoff at critical conditions, whereas the effect of climate change on the stormwater drainage system was more adverse than the effect of land-use.

Flood and Contain: An Optimized Repeal-Based Flooding Algorithm for Wireless Ad Hoc and Sensor Networks

Flooding is a simple yet reliable way of discovering resources in wireless ad hoc networks such as mobile ad hoc networks (MANETs), ad hoc sensors, and recently, IoT networks. However, its operation is resource-intensive, especially in densely populated networks. Several approaches can be found in the literature to reduce the impact of flooding. Many of these approaches follow a repeal-based operation, chasing and stopping further propagation of flooding packets once the target is found. However, repeal-based protocols might end up transmitting even more packets than the original flooding. This work characterizes a maximum repeal-flooding boundary beyond which it is counterproductive to chase the original flooding. We present the Flood and Contain (F&C) algorithm, a method that can quickly establish the maximum repeal-flooding boundary for each node while making no assumptions on the underlying network. F&C’s packet overhead increases linearly with the hop count up to the maximum repeal-flooding boundary, in which case there is no attempt to chase the original flooding. In this latter case, F&C generates only as many packets as the original flooding. Simulations show that, on average, F&C reduces the total flooding overhead (compared to traditional flooding) up to 35 percent once considering all possible destinations, with only a slight increase in resource discovery latency, and it outperforms all other repeal-based protocols, particularly for longer routes.

Modelling of noise reduction for Datacentre buildings fire protection with inert gas systems

Regarding INERGEN Clean gas Total Flood Fire Suppression System, these systems are specifically engineered for total flooding application in either unoccupied or occupied areas, but against its design, or their proved long term efficiency and global scale usage, since INERGEN agent is stored as a gas, it discharges as an invisible gas that can have a more destroying impact than the fire itself. Since 2008 up to now, there have been recorded on yearly basis several reports about INERGEN gas discharges conducting to faults in hard discs (HDD) operating in Data Centres protected by such a solution from fire due to the level of noise produced. The paper shows an analysis of this problem as hard disks damaging source detection and optimization by modelling of nozzle placement in the space choice as a technical solution to avoid these fire extinguisher side effects.

Flood Risk in Szeged before River Engineering Works: A Historical Reconstruction

Szeged situated at the confluence of the Tisza and the Maros Rivers has been exposed to significant flood risk for centuries due to its low elevation and its location on the low floodplain level. After the Ottoman (Turkish) occupation of Hungary (ended in 1686), secondary sources often reported that the town was affected by devastating floods which entered the area from north, and a great part of the town or its whole area was inundated. Natural and artificial infill reduced the flood risk to some extent after the town had been founded, but in the 19th century flood risk was mitigated by river engineering and the reconstruction of the town. The town relief was raised by a huge amount of sediment, which makes it difficult to determine the elevation of the original relief as well as the exact flood risk of the study area. However, some engineering surveys originating from the 19th century contain hundreds of levelling data in a dense control point network making possible to model the relief of the whole town preceding its reconstruction and ground infill. Based on these data, we prepared a relief model which was compared with the known data of the 1772 flood peak, from which we deduced that 60% of the town must have been inundated before it was filled up. As there could have been 50-100 cm thick natural or artificial ground infill since the 11th century, the original natural relief can be gained by deducting these data. Based on this deduction, the extent of inundation centuries ago could reach 85%, which means almost total flooding.