Search results for "Drain"

Strategies investigation in using artificial neural network for landslide susceptibility mapping: application to a Sicilian catchment

2013

Susceptibility assessment of areas prone to landsliding remains one of the most useful approaches in landslide hazard analysis. The key point of such analysis is the correlation between the physical phenomenon and its triggering factors based on past observations. Many methods have been developed in the scientific literature to capture and model this correlation, usually within a geographic information system (GIS) framework. Among these, the use of neural networks, in particular the multi-layer perceptron (MLP) networks, has provided successful results. A successful application of the MLP method to a basin area requires the definition of different model strategies, such as the sample selec…

Long-term dynamics of water-borne nitrogen, phosphorus and suspended solids in the lower Don River basin (Russian Federation)

2011

A long-term study (1986–2002) of water-borne nutrient and suspended solids dynamics was undertaken on the lower Don River, which plays an extremely important role in the water supply of the Black Sea and Azov Sea basin. Suspended solids were greatest in spring and summer and were correlated to river discharge. Mean annual nitrogen concentrations increased from 1986 to 1995 and then decreased from 1996 to 2002. Unlike nitrogen, phosphorus concentrations (both phosphates and total phosphorus) gradually increased throughout the study period changing the river from an oligotrophic to upper mesotrophic status. If this trend continues phytoplankton could become nitrogen-limited leading to the dev…

Tropical Andean forest derives calcium and magnesium from Saharan dust

2008

[1] We quantified base metal deposition to Amazonian montane rain forest in Ecuador between May 1998 and April 2003 and assessed the response of the base metal budget of three forested microcatchments (8–13 ha). There was a strong interannual variation in deposition of Ca [4.4–29 kg ha−1 a−1], Mg [1.6–12], and K [9.8–30]). High deposition changed the Ca and Mg budgets of the catchments from loss to retention, suggesting that the additionally available Ca and Mg was used by the ecosystem. Increased base metal deposition was related to dust outbursts of the Sahara and an Amazonian precipitation pattern with trans-regional dry spells allowing for dust transport to the Andes. The increased base…

Climate change impacts on river runoff in Latvia

2011

In order to assess climate change impacts on river runoff patterns at the end of this cen- tury, the hydrological model METQ2007BDOPT was applied to 8 river basins and sub-basins in Latvia, which is a part of the southeast Baltic Sea basin. The climate data we used originate from the PRUDENCE project and were prepared in a separate study. Changes in hydro-climate were analysed using one control run (1961-1990) and 2 IPCC scenario runs (A2 and B2; 2071-2100). For the A2 sce- nario, both annual and seasonal analysis predicted the major significant changes in most cases. For both scenarios, an increase of the mean annual climate data (air temperature, precipitation and evapo - transpiration) i…

2019

Flooding may damage important transportation infrastructures, such as roads, railways and bridges, which need to be well planned and designed to be able to withstand current and possible future climate-driven increases in flood frequencies and magnitudes. This study develops a novel approach to predictive statistical modelling of the probability of flooding at major road-stream intersection sites, where water, sediment and debris can accumulate and cause failure of drainage facilities and associated road damages. Two areas in south-west Sweden, affected by severe floods in August 2014, are used in representative case studies for this development. A set of physical catchment-descriptors (PCD…

Pluvial flooding in urban areas: the role of surface drainage efficiency

2016

2019

Gully erosion is considered to be one of the main causes of land degradation in arid and semi-arid territories around the world. In this research, gully erosion susceptibility mapping was carried out in Semnan province (Iran) as a case study in which we tested the efficiency of the index of entropy (IoE), the Vlse Kriterijumska Optimizacija I Kompromisno Resenje (VIKOR) method, and their combination. Remote sensing and geographic information system (GIS) were used to reduce the time and costs needed for rapid assessment of gully erosion. Firstly, a gully erosion inventory map (GEIM) with 206 gully locations was obtained from various sources and randomly divided into two groups: A training d…

Impact of climate variability, drainage and land-cover changes on hemiboreal streamflow

2017

ABSTRACTThe aim of the study was to determine the effects of climate variability, agricultural land drainage and afforestation of agricultural land on river discharge. The study was conducted in the Vienziemīte stream basin (6 km2), where discharge was monitored on a daily basis during the time period of 1946–2010. In the stream basin, natural afforestation of agricultural land began in the 1950s, and in the mid-1970s artificial drainage systems were installed in all agricultural land (70% of the total basin area). Climate variability and artificial drainage were the main factors observed to be affecting stream discharge. The changes were most evident in annual and seasonal mean, minimum an…

Dual Multilevel Urban Drainage Model

2005

In urban areas, when heavy rains occur, the discharge capacity of sewers is usually unable to transport the effective rainfall reaching the streets. When the runoff flow rate exceeds the capacity of the storm sewer system, the excess flow is conveyed through the street network as overland flow. A dual model is proposed for modeling the system as a double network, formed by an upper network of open channels (street gutters) and a lower network of closed conduits (sewer pipes). What is new in this model is its capacity to take into account the hydrodynamic relationship between the flows in the upper and lower networks. The model is applied to computing the response of a real monitored basin; …

Assessing uncertainties in urban drainage models

2012

The current state of knowledge regarding uncertainties in urban drainage models is poor. This is in part due to the lack of clarity in the way model uncertainty analyses are conducted and how the results are presented and used. There is a need for a common terminology and a conceptual framework for describing and estimating uncertainties in urban drainage models. Practical tools for the assessment of model uncertainties for a range of urban drainage models are also required to be developed. This paper, produced by the International Working Group on Data and Models, which works under the IWA/IAHR Joint Committee on Urban Drainage, is a contribution to the development of a harmonised framewor…